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Title: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on March 26, 2015, 01:40:33 pm
Hi everyone,

I am wondering who all has heard the new JBL SRX818SP and SRX828SP. I have been looking into getting some smaller subs that I can carry by myself for smaller gigs (smaller wedding DJs, some bar gigs, etc) and am looking for something in the $1k-$1500 range for price (though I plan on getting a pair). I have previously been thinking about the KW181 as I have some K12's that I use for some smaller gigs. I have 4 SRX728s that I use for larger gigs and have really enjoyed those subs-though I wish they extended lower than they do.

Anyways, what I am interested to know is how the SRX800 series stack up against their predecessors in the SRX700 series. Perhaps a fair comparison could be the SRX818SP vs the VRX918SP (which is basically the SRX718 powered from what I understand).

Does anyone have any experience with these subs? How do they sound? How do they match up against a similar line like the KW series, etc.

Thank you all in advance for any input you may have.  :)
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on March 26, 2015, 01:42:00 pm
To add, I am also interested in everyone's thoughts of the SRX828SP vs the SRX728S. Though I am more interested in the smaller single 18 at this point.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Robert Piascik on March 26, 2015, 02:09:34 pm
There's a long thread going on in the Lab Lounge about Danley TH118 and how people love them. I have eight and do events similar to what you mentioned. They're a little more expensive than you stated but they far exceed anything I've ever used and they're reasonably sized. Check them out if you want the best.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on March 26, 2015, 07:21:59 pm
There's a long thread going on in the Lab Lounge about Danley TH118 and how people love them. I have eight and do events similar to what you mentioned. They're a little more expensive than you stated but they far exceed anything I've ever used and they're reasonably sized. Check them out if you want the best.

From what I have heard, they are great subs but I need a single 18 that I can carry by myself-not just roll in by myself. I often times have gigs that are on second floors or up stairs and having a 160lb sub will not work for me to lift by myself.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Jamin Lynch on March 26, 2015, 07:38:36 pm
Hi everyone,

I am wondering who all has heard the new JBL SRX818SP and SRX828SP. I have been looking into getting some smaller subs that I can carry by myself for smaller gigs (smaller wedding DJs, some bar gigs, etc) and am looking for something in the $1k-$1500 range for price (though I plan on getting a pair). I have previously been thinking about the KW181 as I have some K12's that I use for some smaller gigs. I have 4 SRX728s that I use for larger gigs and have really enjoyed those subs-though I wish they extended lower than they do.

Anyways, what I am interested to know is how the SRX800 series stack up against their predecessors in the SRX700 series. Perhaps a fair comparison could be the SRX818SP vs the VRX918SP (which is basically the SRX718 powered from what I understand).

Does anyone have any experience with these subs? How do they sound? How do they match up against a similar line like the KW series, etc.

Thank you all in advance for any input you may have.  :)

I haven't heard the new SRX800 series yet, but I do have the VRX918SP subs. These are really good sounding little subs that I use for small events. They go pretty low and can get reasonably loud.

If you look at the spec sheet only the SRX818sp is a little louder than the VRX918sp. The cabinet looks real similar to the STX style

I have 4 that I use for club bands for about 150 or so folks. Since I have 4 it makes my small club rig modular. Some places 2 and some places 4. I'm real happy with them. They do have their limitations though.

I mounted casters on the back side and have covers with hard tops. So I can load stuff on the top without pushing the grill down. Real easy to move around.

Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Scott Carneval on March 27, 2015, 11:13:15 pm
I haven't heard the new SRX800 series yet, but I do have the VRX918SP subs. These are really good sounding little subs that I use for small events. They go pretty low and can get reasonably loud.

If you look at the spec sheet only the SRX818sp is a little louder than the VRX918sp. The cabinet looks real similar to the STX style



One thing to note about the spec sheet on the VRX918 is it's measured in full space.  The SRX818 doesn't specify, but I would assume it's measured in half space to get it's 1w1m number, and then calculated from there.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on March 30, 2015, 03:24:05 pm
So it sounds like no one really has any real world experience with these subs yet. If anyone does in the future, it would definitely be interested to hear of their findings!
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Lee Buckalew on March 30, 2015, 07:56:16 pm
So it sounds like no one really has any real world experience with these subs yet. If anyone does in the future, it would definitely be interested to hear of their findings!

I am scheduled to demo some on Friday but don't know how in depth I will be able to get. Most likely it will be listening in a limits way and no measurement. 
If I can get more in depth than that I'll let you know what I find.

Lee
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on April 01, 2015, 02:28:01 pm
I am scheduled to demo some on Friday but don't know how in depth I will be able to get. Most likely it will be listening in a limits way and no measurement. 
If I can get more in depth than that I'll let you know what I find.

Lee

That would be awesome, Lee!   :D
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Lee Buckalew on April 04, 2015, 09:29:58 pm
That would be awesome, Lee!   :D

Demo was postponed until this coming week.
I'll see how in depth I can get.

Lee
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on April 22, 2015, 05:28:52 pm
Demo was postponed until this coming week.
I'll see how in depth I can get.

Lee

Have you gotten a chance to demo them yet?
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Lee Buckalew on April 22, 2015, 06:10:01 pm
Have you gotten a chance to demo them yet?

Unfortunately the only box that the rep brought in was the two-way, 15".  I have not had the chance to hear anything else yet.

Lee
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Drew Tronvig on May 20, 2015, 04:25:39 am
So has anyone seen the SRX818SP yet? The easiest question is probably how it compares acoustically to the PRX618S-XLF, which aside from the DSP and networking looks pretty similar.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Mike Santarelli on May 28, 2015, 09:58:02 am
So has anyone seen the SRX818SP yet? The easiest question is probably how it compares acoustically to the PRX618S-XLF, which aside from the DSP and networking looks pretty similar.

I was able to listen and compare the srx818 to the qsc kw181 last night but not the PRX.

While the kw181 sounds great, the srx818 was much deeper and fuller.  I think overall volume was close but the jbl was much fuller. 
I've never had a complaint about the w181 for live music use but I am really wanting to get the new srx828sp.  They srx835 and 815 were also incredible.  Much smoother than everything else in that market at the moment. 

I'm curious to see how qsc responds with their next series.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on June 20, 2015, 11:32:07 pm
I was able to listen and compare the srx818 to the qsc kw181 last night but not the PRX.

While the kw181 sounds great, the srx818 was much deeper and fuller.  I think overall volume was close but the jbl was much fuller. 
I've never had a complaint about the w181 for live music use but I am really wanting to get the new srx828sp.  They srx835 and 815 were also incredible.  Much smoother than everything else in that market at the moment. 

I'm curious to see how qsc responds with their next series.

Were you able to hear the srx828 yet?
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Mike Santarelli on June 22, 2015, 12:44:30 am
Were you able to hear the srx828 yet?

Not yet but I have srx828's on the way.  I should have them this week and I'll report back.  I did get the srx835's and I can without a doubt say that after 4 gigs with them, my kw152's are not in the same league. The 835's also will run away from the  kw181.  I'm hoping I'm as blown away with the subs as I am the mains.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Mike Santarelli on June 25, 2015, 08:35:53 pm
I received one of my srx828's. 

I would 100% recommend going with the 828 over two kw181's if you can transport them.  I just did some small testing in my garage and the srx sounds much cleaner even when pushed.  I think it would take 3 kw181's to equal one Srx828.  The srx hits deeper and has an overall better sound quality.

The 181 is no slouch and I will still use them for small shows.  I can't wait until my other 828 comes. On back order now.

I had to run the 181's nearly flat out to get anywhere close to the 828, and the 828 was as still a good bit louder and could be felt more. 

I will use the 828 live this weekend and report back.  As of now it's a great sounding sub and worth the size vs price of two separate subs IMO.   

I think the srx728 with proper power packs a little more  punch but I'll take trade off of low power consumption and built in amps for the majority of my gigs.  I should be able too compare the 728 and 828 in the next few weeks but it gets tough comparing active and passive gear.

Just wanted to mention I did the test in srx top mode as well as 100hz to be fair to kw181's. 
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Steve Garris on June 26, 2015, 03:29:48 pm
Mike, are there speaker pole cups on those 828sp's? I'm looking at the images and don't see any, but the description states pole/tripod mounts.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Mike Santarelli on June 26, 2015, 07:49:14 pm
Mike, are there speaker pole cups on those 828sp's? I'm looking at the images and don't see any, but the description states pole/tripod mounts.

No pole mounts.  If there is one recommendation I could make it would be add like cups.  I did stand the sub vertical and put an 835 on top.  It is very stable as long as the ground is flat.  Puts the speaker height decent enough for most gigs.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Ivan Beaver on June 26, 2015, 08:21:36 pm
No pole mounts.  If there is one recommendation I could make it would be add like cups.
Pole cups are a VERY INTERESTING situation.

Some people would love to have pole cups, and understand the usefulness.

But others INSIST that if a product has a pole cup on it, they WILL NOT EVEN CONSIDER using it-because to them a pole cup means MI to them.

Both sides are very passionate about their feelings and refuse to see the other side (kind of like politics)

The only way to satisfy both sides is to offer it as an option.

 
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on July 13, 2015, 02:08:43 pm
I received one of my srx828's. 

I would 100% recommend going with the 828 over two kw181's if you can transport them.  I just did some small testing in my garage and the srx sounds much cleaner even when pushed.  I think it would take 3 kw181's to equal one Srx828.  The srx hits deeper and has an overall better sound quality.

The 181 is no slouch and I will still use them for small shows.  I can't wait until my other 828 comes. On back order now.

I had to run the 181's nearly flat out to get anywhere close to the 828, and the 828 was as still a good bit louder and could be felt more. 

I will use the 828 live this weekend and report back.  As of now it's a great sounding sub and worth the size vs price of two separate subs IMO.   

I think the srx728 with proper power packs a little more  punch but I'll take trade off of low power consumption and built in amps for the majority of my gigs.  I should be able too compare the 728 and 828 in the next few weeks but it gets tough comparing active and passive gear.

Just wanted to mention I did the test in srx top mode as well as 100hz to be fair to kw181's.

Mike, have you had a chance to compare the SRX828 vs SRX728?

Also, I'm curious what the 818 vs the kw181 turns out to be. I'm more interested in a single 18 at this point because I need a system that I can carry by myself and take up stairs at some gigs. My 728s are great when I have roll-in access or help but for smaller gigs I'd like the portability of a single 18.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Mike Santarelli on July 14, 2015, 09:58:21 am
Mike, have you had a chance to compare the SRX828 vs SRX728?

Also, I'm curious what the 818 vs the kw181 turns out to be. I'm more interested in a single 18 at this point because I need a system that I can carry by myself and take up stairs at some gigs. My 728s are great when I have roll-in access or help but for smaller gigs I'd like the portability of a single 18.

With an itech 12000hd, the srx728 may have a little more punch but it's very close.  I will know for certain next weekend. My second 828 just arrived and I've only run the 728's in pairs. .  Sound quality is very close. I think I prefer the overall sound of the 828.  If I were starting from scratch I'd go with the srx828 but if you already an srx728 with quality amp I'd stay put. For value an quality the srx800 is hard to beat.  I did get into the limiters last gig but sound quality remained intact.  I have heard the srx728 get farty at times but not so much from the 828. I'm sure the DSP has a lot to do with it.

When I compared the srx818 vs kw181 in store the 818 was much better.  I do a weekly gig outdoors in an area about 150 long by 75ft wide. I was using two kw181's center clustered up until a few weeks ago when I got my srx828.  One 828 smashes two kw181's.  The bottom end is much more defined and has the punch you can feel and hear.  The kw181 bass can be heard but not felt IMO.  The kW is a great sounding sub but the srx is much better.

The owner of one of the bigger sound companies in my area was at the show Sunday night and at show a last month for the same band when I used the kw181's.  He immediately noticed the bottom end.  Said it was more defined, punchier, and clear.  I agree. I could still feel the bass 50-75ft from the stage which I could not with the 181.  I think it's going to be insane with the second 828.  Honestly, one works just fine for this venue and styles of music but a second will be the icing on the cake. 

My initial interest started with a big sounding box with little current draw.  I have run into shoddy power using itechs before even though they were on 20 amp lines.  I have no such worries with the srx800.

I would take the srx818 over any similarly priced competitor and even some higher priced boxes like the vrx.  They do have their limits but if used as intended I think most users will be more than happy. 

I'll get back to you once I use both subs Sunday.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Debbie Dunkley on August 13, 2015, 06:25:12 pm
With an itech 12000hd, the srx728 may have a little more punch but it's very close.  I will know for certain next weekend. My second 828 just arrived and I've only run the 728's in pairs. .  Sound quality is very close. I think I prefer the overall sound of the 828.  If I were starting from scratch I'd go with the srx828 but if you already an srx728 with quality amp I'd stay put. For value an quality the srx800 is hard to beat.  I did get into the limiters last gig but sound quality remained intact.  I have heard the srx728 get farty at times but not so much from the 828. I'm sure the DSP has a lot to do with it.

When I compared the srx818 vs kw181 in store the 818 was much better.  I do a weekly gig outdoors in an area about 150 long by 75ft wide. I was using two kw181's center clustered up until a few weeks ago when I got my srx828.  One 828 smashes two kw181's.  The bottom end is much more defined and has the punch you can feel and hear.  The kw181 bass can be heard but not felt IMO.  The kW is a great sounding sub but the srx is much better.

The owner of one of the bigger sound companies in my area was at the show Sunday night and at show a last month for the same band when I used the kw181's.  He immediately noticed the bottom end.  Said it was more defined, punchier, and clear.  I agree. I could still feel the bass 50-75ft from the stage which I could not with the 181.  I think it's going to be insane with the second 828.  Honestly, one works just fine for this venue and styles of music but a second will be the icing on the cake. 

My initial interest started with a big sounding box with little current draw.  I have run into shoddy power using itechs before even though they were on 20 amp lines.  I have no such worries with the srx800.

I would take the srx818 over any similarly priced competitor and even some higher priced boxes like the vrx.  They do have their limits but if used as intended I think most users will be more than happy. 

I'll get back to you once I use both subs Sunday.

Update??
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on September 15, 2015, 11:28:32 pm
With an itech 12000hd, the srx728 may have a little more punch but it's very close.  I will know for certain next weekend. My second 828 just arrived and I've only run the 728's in pairs. .  Sound quality is very close. I think I prefer the overall sound of the 828.  If I were starting from scratch I'd go with the srx828 but if you already an srx728 with quality amp I'd stay put. For value an quality the srx800 is hard to beat.  I did get into the limiters last gig but sound quality remained intact.  I have heard the srx728 get farty at times but not so much from the 828. I'm sure the DSP has a lot to do with it.

When I compared the srx818 vs kw181 in store the 818 was much better.  I do a weekly gig outdoors in an area about 150 long by 75ft wide. I was using two kw181's center clustered up until a few weeks ago when I got my srx828.  One 828 smashes two kw181's.  The bottom end is much more defined and has the punch you can feel and hear.  The kw181 bass can be heard but not felt IMO.  The kW is a great sounding sub but the srx is much better.

The owner of one of the bigger sound companies in my area was at the show Sunday night and at show a last month for the same band when I used the kw181's.  He immediately noticed the bottom end.  Said it was more defined, punchier, and clear.  I agree. I could still feel the bass 50-75ft from the stage which I could not with the 181.  I think it's going to be insane with the second 828.  Honestly, one works just fine for this venue and styles of music but a second will be the icing on the cake. 

My initial interest started with a big sounding box with little current draw.  I have run into shoddy power using itechs before even though they were on 20 amp lines.  I have no such worries with the srx800.

I would take the srx818 over any similarly priced competitor and even some higher priced boxes like the vrx.  They do have their limits but if used as intended I think most users will be more than happy. 

I'll get back to you once I use both subs Sunday.

Hey Mike, have you had a chance to compare them yet?
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Steve Garris on September 21, 2015, 12:53:44 pm

When I compared the srx818 vs kw181 in store the 818 was much better.  I do a weekly gig outdoors in an area about 150 long by 75ft wide. I was using two kw181's center clustered up until a few weeks ago when I got my srx828.  One 828 smashes two kw181's.  The bottom end is much more defined and has the punch you can feel and hear.  The kw181 bass can be heard but not felt IMO.  The kW is a great sounding sub but the srx is much better.



I'm curious, when you did the 818 to KW118 comparison in the store, had the sales rep's  used the volume knobs to match the output of these two speakers? Or perhaps they went in to the networking to increase the gain?

I just purchased (2) 818's, and out of the box they do not match the level of my PRX sub's. I've used KW118's and loved them, so I cannot imagine how the 818's could be louder without the networking changes.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Mike Santarelli on September 25, 2015, 11:24:37 pm
I'm curious, when you did the 818 to KW118 comparison in the store, had the sales rep's  used the volume knobs to match the output of these two speakers? Or perhaps they went in to the networking to increase the gain?

I just purchased (2) 818's, and out of the box they do not match the level of my PRX sub's. I've used KW118's and loved them, so I cannot imagine how the 818's could be louder without the networking changes.

Overall volume was as close as we could get it with the constraints involved.  I did use an spl meter on my phone but I don't really trust it anymore since I used a real meter and found my phone was a good bit off.   The kw181's get very loud for such a small box. Kind of scary.  I don't feel the 818 was necessarily louder volume wise, just much fuller and robust. Lower bottom end.  The kW sounds very flat in comparison.  I found it similar at home when I tested the two kW's vs one 828.  The 828 was definitely louder and sounded much better.  I tested at 100hz to be fair.

I love my kw181's but know they are not in the same league as the srx800 in terms of overall sound. 

I love the prx618 and 718 subs as well but I never compared them to the srx800 but feel they would close.  The 800 should be more refined and I'd imagine would sound better in a live setting.  I didn't play with the makeup gain on the subs but did with the mains and it was a huge difference in output.  If you haven't used them live I'd wait until you do to make a final call.  The 618 and 718 are great subs so the 818 might not be a big upgrade but should better overall. 

In response to other questions I have used the 828's enough now to trust that I prefer them to the 728. I did kind of like the box size more on the 728 but it's no biggie.  Output is close but I give the edge to a properly powered 728. Sound quality I prefer the 828.  They are also more responsive in smaller settings. They don't need to be worked as hard to give up the goods.

If I alredy had 728's of my own with a great amp like an itech or similar I'd probably stay put as the speakers are close in performance.  If I were looking into my first set of dual 18's and buying from scratch  I'd go with the 828. I think it wins In sound quality and is probably pound for pound untouchable.

Steve, just thought of this.  I have been running my subs on a mono master channel.  I only send low Frequency instruments to them. I've been using a soundcraft si and the LR and mono master buses work great for this. I have some flexibility and can boost my overall level to the subs if needed.  How are you running your 818's? 
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Steve Garris on September 28, 2015, 01:18:04 pm
Overall volume was as close as we could get it with the constraints involved.  I did use an spl meter on my phone but I don't really trust it anymore since I used a real meter and found my phone was a good bit off.   The kw181's get very loud for such a small box. Kind of scary.  I don't feel the 818 was necessarily louder volume wise, just much fuller and robust. Lower bottom end.  The kW sounds very flat in comparison.  I found it similar at home when I tested the two kW's vs one 828.  The 828 was definitely louder and sounded much better.  I tested at 100hz to be fair.

I love my kw181's but know they are not in the same league as the srx800 in terms of overall sound. 

I love the prx618 and 718 subs as well but I never compared them to the srx800 but feel they would close.  The 800 should be more refined and I'd imagine would sound better in a live setting.  I didn't play with the makeup gain on the subs but did with the mains and it was a huge difference in output.  If you haven't used them live I'd wait until you do to make a final call.  The 618 and 718 are great subs so the 818 might not be a big upgrade but should better overall. 

In response to other questions I have used the 828's enough now to trust that I prefer them to the 728. I did kind of like the box size more on the 728 but it's no biggie.  Output is close but I give the edge to a properly powered 728. Sound quality I prefer the 828.  They are also more responsive in smaller settings. They don't need to be worked as hard to give up the goods.

If I alredy had 728's of my own with a great amp like an itech or similar I'd probably stay put as the speakers are close in performance.  If I were looking into my first set of dual 18's and buying from scratch  I'd go with the 828. I think it wins In sound quality and is probably pound for pound untouchable.

Steve, just thought of this.  I have been running my subs on a mono master channel.  I only send low Frequency instruments to them. I've been using a soundcraft si and the LR and mono master buses work great for this. I have some flexibility and can boost my overall level to the subs if needed.  How are you running your 818's?

Thanks for the info Mike. I found that I could get the added volume I need for the 818's by simply using both inputs (added about 3 db). I feel the system is better balanced now with my PRX615 tops. I've got the 818's set using the 100 Hz pass filter. I run my tops in "Main" mode which is full-range. I'm going to experiment with the new subs at my gig this coming weekend, trying the 80 Hz filter as well. If you saw my thread on the Lounge forum, I retested the subs using more input signal and much louder than my first test. The db meter showed a higher output and yes, I could hear that lower extension everyone is talking about. I wish I had room for the 828's!
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Debbie Dunkley on September 28, 2015, 01:26:44 pm
I am finding it very interesting that there are a number of posts on various threads here at PSW that refer to  'manipulating' DSP and configuration in order to get higher SPL on the SRX818 and 828. Surely we shouldn't have to do any of this - isn't one the main reasons for choosing powered boxes so that we don't have to overthink things and we can just plug and play (for the most part) ?
Before these SRX threads, I hadn't heard of using compression make-up gain or using both channel inputs in order to get more gain from the system. Does this seem odd to anyone else that we should even have to go there?
My understanding in the past has been that in order to balance the lows to the highs, we would simply use the level pots on the back of the units till balanced. Why is this not sufficient anymore?
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Jamin Lynch on September 28, 2015, 01:38:03 pm
I am finding it very interesting that there are a number of posts on various threads here at PSW that refer to  'manipulating' DSP and configuration in order to get higher SPL on the SRX818 and 828. Surely we shouldn't have to do any of this - isn't one the main reasons for choosing powered boxes so that we don't have to overthink things and we can just plug and play (for the most part) ?
Before these SRX threads, I hadn't heard of using compression make-up gain or using both channel inputs in order to get more gain from the system. Does this seem odd to anyone else that we should even have to go there?
My understanding in the past has been that in order to balance the lows to the highs, we would simply use the level pots on the back of the units till balanced. Why is this not sufficient anymore?

Give that lady an award

I said a long time ago that it seems more like "you don't have enough rig for the gig". Then I got jumped on. Oh well. I'm glad Debbie could figure it out too
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Lyle Williams on September 28, 2015, 04:08:40 pm
Maybe there has been a bad design assumption, like "line level signal peaks are +22dB" or something like that.

Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Steve Garris on September 28, 2015, 04:56:23 pm
I am finding it very interesting that there are a number of posts on various threads here at PSW that refer to  'manipulating' DSP and configuration in order to get higher SPL on the SRX818 and 828. Surely we shouldn't have to do any of this - isn't one the main reasons for choosing powered boxes so that we don't have to overthink things and we can just plug and play (for the most part) ?
Before these SRX threads, I hadn't heard of using compression make-up gain or using both channel inputs in order to get more gain from the system. Does this seem odd to anyone else that we should even have to go there?
My understanding in the past has been that in order to balance the lows to the highs, we would simply use the level pots on the back of the units till balanced. Why is this not sufficient anymore?

For me, it is because I would have to turn my tops down to the point of having to run my board fairly deep into the red in order to get the same output. That 3db of volume I got from using both inputs made a huge difference.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Debbie Dunkley on September 28, 2015, 05:18:06 pm
For me, it is because I would have to turn my tops down to the point of having to run my board fairly deep into the red in order to get the same output. That 3db of volume I got from using both inputs made a huge difference.

I had never heard of this practice before now Steve and would never have thought of doing such a thing till I read about it here. Do you not get the levels you want from simply reducing the gain slightly on the subs to match the tops instead?
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Jamin Lynch on September 28, 2015, 05:45:55 pm
For me, it is because I would have to turn my tops down to the point of having to run my board fairly deep into the red in order to get the same output. That 3db of volume I got from using both inputs made a huge difference.

So you have to turn down the tops, run the mixer in the red and squeak out every extra dB you can get from the subs so they will keep up?  :o
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Steve Garris on September 29, 2015, 12:05:28 am
So you have to turn down the tops, run the mixer in the red and squeak out every extra dB you can get from the subs so they will keep up?  :o

Yes. The volume on the subs is all the way up. My tops are at their usual setting of 12 o'clock. By plugging into both inputs on the subs, I feel the system is now balanced. First gig with them is next weekend.  I'll report back here after that.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Luke Geis on September 30, 2015, 01:27:50 am
It doesn't sound like it makes sense until you use them and go " ok where is all that SPL at "?

Should we be able to get the level needed without DSP manipulation? The answer is yes you can and will, but you have to run the mixer pretty hot. Here is my findings as to why.

1. The input metering is the dbfs representation of the analog signal sent to the speaker.

2. The metered input when scaled against the output metering on the speaker is almost identical. I.E. what goes in is about what comes out. I am referring to available headroom on the input vs. the output.

3. In order to get the SPL that is indicative of a rock show, you have to be sending signal that is around -10dbfs or less of clipping. This is above unity gain on most mixers. The issue isn't so much the need to run the mixer hotter, but that the peaks can sometimes creep very close if not all the way to clipping on the speakers inputs and it's output section, as well as the mixer. 

It has something to do with the speakers input sensitivity. It is different from most powered speakers and amps. It is almost like they scaled it so that the output always matches the input in terms of headroom. This makes sense as you can look at the input metering and know how close you are to limiting and clipping. Most powered speakers simply show a clip light and produce whatever level of volume they produce. The input level knob is simply for attenuation. With the SRX you can adjust the DSP sections output level from ∞ to +12db. It has a unity gain.

So where is the breakdown? The input of the speaker shows a level from ∞ to +12db as well. So when you set the input and the master output level both to unity or 0db, there is a 12db deficiency in potential level from the speakers input. There is also a potential 12db of gain that you could add back with the output. I think this was done so you could maximize the gain structure with just about any mixer.

What most are not understanding of is that the speakers SPL output is pretty relative to its metered input and of course its metered output. So you have to be running pretty close to +16dbu if you want rock show SPL levels. This means that many mixers will be between unity and clipping and likely closer to clipping if you plan on getting close to the speakers potential output.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Tim McCulloch on September 30, 2015, 08:32:06 pm
THERE IS NO SUCH THING AS "UNITY" AS AN OPERATING LEVEL.  Kindly purge the word, as used in this context, from your vocabulary.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Luke Geis on October 01, 2015, 12:35:41 am
As an operating level no, but as a reference level yes....... The point I was making above was not that I ( or anyone else ) want to set it up so the mixer, speakers and everything else are OPERATING at their respective " UNITY " gains, but more that you will be running the mixer hotter than you're used to and it may be rather close to clipping. Unity is not the problem ( and in digital doesn't technically exist at all ), it's the lack of available headroom in the mixer once SPL is achieved.

The tricks as prescribed in other threads simply allow you to get a little more, while running both the mixer and the speaker at a safer metered level; I.E. not close to clipping.........
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: David Sturzenbecher on October 01, 2015, 10:34:13 am
There is one other place to adjust gain inside this SRX828SP.   It is the processing output fader.  This fader does not appear on any of the stock control panels JBL gives you.   If you create a new custom panel, then find CH1 and CH2 processing output, the first parameter listed will be the "fader" control.  It appears to allow for an additional 12 dB of gain. Just grab those parameters and drag them to your custom panel, and then launch.  The common output fader as seen in my screenshot tracks the fader on the stock panel.

Also note, there are about 500 other parameters in this "venue explorer" list that can be placed on custom panels and monitored or adjusted. Use this at your own risk...it's not my fault if you change the limiter settings and blow your stuff up.

Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: drew gandy on October 12, 2015, 12:16:41 pm
As an operating level no, but as a reference level yes....... The point I was making above was not that I ( or anyone else ) want to set it up so the mixer, speakers and everything else are OPERATING at their respective " UNITY " gains, but more that you will be running the mixer hotter than you're used to and it may be rather close to clipping. Unity is not the problem ( and in digital doesn't technically exist at all ), it's the lack of available headroom in the mixer once SPL is achieved.

Luke I think you've got this figured out but you have an issue with terminology.  And it's partly the fault of manufacturers.  Unity, as it pertains to audio equipment, means that the device doesn't amplify or attenuate the signal at all.   The level that goes in is the level that comes out.  Unity tells us about how much 'gain' that particular stage or piece of equipment is applying to the signal.  With an audio device like a mixing console or distribution amplifier, if you set all the level controls to unity then you should be able to completely bypass the device (cable right around it) and the sound level won't change. 

+4dBu on the other hand is a reference level.  It represents approximately 1.23v RMS of signal level.  Some powered speakers may be calibrated to achieve "maximum output" with this input signal level (allowing something like 12dB or more of "headroom" on your mixer output) but other speakers may be calibrated to something else like full output at -10dBV or perhaps even +20dBu!

If we look at a power amplifier by itself (no speaker) then we can analyze the amount of gain offered.  Most pro amps are on the order of 30dB of voltage gain with their input controls turned all the way up.  It's fairly simple.  Unfortunately, a powered speaker is somewhat of a black box.  We have input circuitry, a crossover and EQ section, an amplifier and then speakers.  Very few manufacturers give us information about what is going on in these various stages.  And if they do, it's usually marketing oriented (intended to impress) and it is moistly meaningless because it's just one tiny cog in the greater machine.  The only way to really analyze the gain of this black box is to look at the amount of electrical signal going in and compare that to the SPL coming out. This can give us useful information for designing a sound system but very few manufacturers give this info.  So, to use this kind of info for comparison means we would likely have to measure every speaker we want to compare. 

Some manufacturers put some kind of scale on their powered speaker level controls that make us think that they are referenced to some kind of standard.  In my experience, this is generally not the case.  It's entirely up to the manufacturer and it seems that many err on the side of more gain rather than less. 

I'll say it out loud.  One of the main advantages (to manufacturers) of the powered speaker is that it puts the magic back in the product.  Since it's a system of itself, many parameters are obscured and it makes comparing the product based on the spec sheets alone, difficult.  Comparing from spec sheet has always been risky, especially with speakers, but with powered boxes we are removed at least another step from where we were with separates. 

The other useful parameter is how loud the black box can get before it reaches it's limit (or sounds bad).  Many manufacturers publish a number that is supposed to reflect this parameter but of course, it's a simple answer to a complex question.  Very often it is a useless column on the spec sheet.  As is always recommended, we need to measure and listen (in context if possible) to really make a comparison.  Even then we are likely to be fooled by some aspect of the system. 

Looking at the spec sheet for the JBL SRX828SP I see a spec for "Line Input Gain".  This is listed as 21dB.  I have no way to be sure about how this relates to the system as a whole but it sounds like it's supposed to be telling me the total electrical gain in the system.  21dB sounds pretty low to me, especially for what is supposed to be a haystack subwoofer.  If we look at the math...  The maximum input level is 20 dBu (7.75v).  If that is then amplified by 21dB in the amplifier circuitry we have 87v RMS.  Into an 8 ohm load we get almost 950 watts. This implies that we need about 19dBu of input to saturate the (750w) amplifier.  David's suggestion that you can possibly apply 12dB more gain buried in the dsp might be a good way to make it match up with other products!  Of course, I'm reading between the lines here. 
 
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Luke Geis on October 13, 2015, 03:57:32 am
I don't even think it's a terminology thing..................  I never really brought up unity and when I did, it was more for reference, not an operational standard. I only mention that the SRX-800 has a unity gain setting. The metering is in dbfs however and unity for digital technically doesn't exist.

The only point I am trying to make is that the SRX series will likely have most users wanting to find more SPL sooner so it matches their current operational standards. There is nothing wrong with the SRX powered line at all. The way it works is simple:

The max input before clipping is 21dbu, at which point the output of the amp will be clipping as well.

The level metering is different than most all are used to. It is in dbfs ( digital scale ) and has no relation to analog metering levels.

The SPL produced by the speaker is pretty linear to its input. The ratio of input to output makes sense, but is not akin to the way other equipment seems to work. Many are used to having the SPL needed by about the time unity gain is hit on the mixers output buss. These speakers will not start producing that same relative level until you are producing right around 16dbu. This leaves about 5-6dbu of headroom in the speaker. Many lower end mixers will be nearly out of headroom by then. In essence the output of the mixer will be close to clipping right about the time the speaker is.

The +12db available at the speakers master output is the quick and easy way to get you more SPL quicker ( by +12db of course ), but is only giving you exactly what it says. The little cheat dubbed the " make up gain technique " allow you to acquire +14-16db of gain before clipping at the same point as simply turning up the master level to +12. More for less; no more, no less.......

Forget that I ever mentioned unity. I know what it is. It is not relevant to the way these speakers operate other than for reference.





Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Tom Bryant on October 13, 2015, 03:27:15 pm
I don't even think it's a terminology thing..................  I never really brought up unity and when I did, it was more for reference, not an operational standard. I only mention that the SRX-800 has a unity gain setting. The metering is in dbfs however and unity for digital technically doesn't exist.

The only point I am trying to make is that the SRX series will likely have most users wanting to find more SPL sooner so it matches their current operational standards. There is nothing wrong with the SRX powered line at all. The way it works is simple:

The max input before clipping is 21dbu, at which point the output of the amp will be clipping as well.



The level metering is different than most all are used to. It is in dbfs ( digital scale ) and has no relation to analog metering levels.

The SPL produced by the speaker is pretty linear to its input. The ratio of input to output makes sense, but is not akin to the way other equipment seems to work. Many are used to having the SPL needed by about the time unity gain is hit on the mixers output buss. These speakers will not start producing that same relative level until you are producing right around 16dbu. This leaves about 5-6dbu of headroom in the speaker. Many lower end mixers will be nearly out of headroom by then. In essence the output of the mixer will be close to clipping right about the time the speaker is.

The +12db available at the speakers master output is the quick and easy way to get you more SPL quicker ( by +12db of course ), but is only giving you exactly what it says. The little cheat dubbed the " make up gain technique " allow you to acquire +14-16db of gain before clipping at the same point as simply turning up the master level to +12. More for less; no more, no less.......

Forget that I ever mentioned unity. I know what it is. It is not relevant to the way these speakers operate other than for reference.
I played outside this weekend and had my 2-818's on on each side about 20ft apart with +15 comp make up gain and the volume on the back at 7.  The level indicators on the the back were only hitting about 80 to 90% during a loud drum solo, with the kick real loud and chest pounding kick.  I think this technique is great to get the most spl out of the subs and I had more to give on the master volume on the mixer!   I had my 812 top at +10 comp and the volume on the back at 0.  The system sounds great, balanced and had lots of compliments on the sound Sunday!  I like the sound of my new SRX800's for FOH better that my old SRX718's with a Itech4000.
 
Thanks for the help on dialing in my new SRX818's.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Scott Holtzman on October 16, 2015, 03:02:04 am
Interesting point is since the processing is in the digital domain  no power is added it's just a shift to the right.  The a/d converter is where the power is made.  Being an analog device it will have an output power rating and a signal to noise ratio.  In a powered speaker gain staging past the input is irrelevant to the user. 

Sent from my SM-T800 using Tapatalk
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Marjan Milosevic on October 16, 2015, 01:04:59 pm
I wonder how they come up with the 141db peak if the amp is 2000W peak.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Ivan Beaver on October 16, 2015, 01:49:21 pm
I wonder how they come up with the 141db peak if the amp is 2000W peak.
Since 2000 watts is a gain of 33dB, then that would mean the sensitivity HAS to be 108dB with 1 watt applied (at some freq----) for a sub.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Luke Geis on October 17, 2015, 04:44:09 am
I will put it simply...... The SRX line will not produce the stated peak SPL ever....... Period. They will get very close and sound good doing it though. Looking through the deep editing features it almost seems possible to bypass a couple of the safety features, or at least augment even further than what has been done thus far. This may yield the results they spec., but I doubt it?
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Jamin Lynch on October 26, 2015, 03:14:00 pm
I will put it simply...... The SRX line will not produce the stated peak SPL ever....... Period. They will get very close and sound good doing it though. Looking through the deep editing features it almost seems possible to bypass a couple of the safety features, or at least augment even further than what has been done thus far. This may yield the results they spec., but I doubt it?

So is JBL lying, misleading the facts, incorrect, or don't know what they are doing? What are you implying?
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Luke Geis on October 26, 2015, 10:21:25 pm
I don't think they are lying. I think they did the test in a way that gets the number. A pink noise burst with a 3db crest factor perhaps? I don't know. What I am saying is that not You, Me, nor anyone else, will never see that spec come to life in real world use. As far as I can tell the speakers will produce an at best peak of about 3-6db below the stated peak spec. This is a short term allowance though. The true output that is practical for these speakers is closer to 6-9db lower than the stated peak. Still not bad though when you consider that your sitting at about 130db in SPL that can actually be produced! If you get that loud I don't want to be around.

I took some time to play with the panels that Audio Architect has. It offers some deep editing and more metering options. I didn't find any way to alter the output production beyond what is available in the normal editing window, but did find some other interesting things I will note below:

1. You can see the metering for just about everything. Temperature, incoming voltage, output voltage; RMS, peak and channel gains. If you want to see the meter for something, you can probably set it up to monitor it.

2. You can edit the amps output channels independently for gain, EQ, limiting and a couple other options. You can turn off the lows or the highs if you want.

3. There is auxillary EQ, guest EQ and other options for settings that you allow for multiple uses.

4. You can use different EQ's for each input channel and adjust limiting and other features independent of the other channel.

While I was not able to get more from the speaker it was neat to see what it was doing. Some things I noticed. The temperature meter stays pretty stable once up and running. There is a lot of thermal room in these amps as far as I can tell. The limiting of the outputs did not actually show up for me even though I was showing limiting in the UI. It leads me to believe that the limiting you do see is in the digital realm and not necessarily at the amps? Still not confirmed with that though....... I have still yet to see the limit light in the UI change from green to yellow. How can you be clipping at the amps and not have any limiting? I think the UI is designed to scare you a little. There is more in there for sure, otherwise why would they give you the ability to do so? The EQ has the option to use an all pass filter in which you can add gain........ Another option I have not played with yet. So to cap things up, JBL is probably not lying at all, but the product they have provided will require some user tweaks to get close to the stated specs. I stand by my statement that the speaker will not produce the stated peak number though. You would not want or hopefully need to though. They sound real good all the way to the point where they are more than loud enough for their intended use. I can get 116db C at 26' from the speakers at the point when the UI says they are limiting. This is 6db more than I thought I would get and 16db more than the venue wanted to produce. That is also 3 generations away from the speakers! The power is there, they just need a little push is all.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: David Sturzenbecher on October 26, 2015, 11:22:46 pm
The limiting of the outputs did not actually show up for me even though I was showing limiting in the UI. It leads me to believe that the limiting you do see is in the digital realm and not necessarily at the amps? Still not confirmed with that though....... I have still yet to see the limit light in the UI change from green to yellow. How can you be clipping at the amps and not have any limiting? I think the UI is designed to scare you a little.

Luke,
I do not have one of these speakers so I cannot test the following, maybe you can.    The green limit light on the stock UI is derived from the "common output" object.   This is the first series of devices where I have seen this specific block. It's possible this object is just an aggregate of the individual limiter blocks from the entire amp.    You may try placing the "gain meter" from within the peak limiter, rms limiter, thermal limiter, or processing output objects onto a custom panel meter and check limiting that way?   Those are the usual suspects for limiting on most crown amps I have come across. You could also temporarily adjust the limiter voltage so something very low (10V) and check to see if that trips the LED indicators.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on October 19, 2016, 11:31:19 pm
So my real question from all of this: do I keep my iTech 8000s and SRX728s or sell them and go for the SRX828sp? I am currently debating between buying another pair of 728s or selling it all to go with a powered solution. I currently have 4 SRX728s and 3 iTech 8000s so I could easily add another pair of subs off of the 3rd iTech.

What are peoples' thoughts now that the SRX828 has been out on the market for a while and in use?
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Art Welter on October 20, 2016, 09:54:41 am
So my real question from all of this: do I keep my iTech 8000s and SRX728s or sell them and go for the SRX828sp? I am currently debating between buying another pair of 728s or selling it all to go with a powered solution. I currently have 4 SRX728s and 3 iTech 8000s so I could easily add another pair of subs off of the 3rd iTech.

What are peoples' thoughts now that the SRX828 has been out on the market for a while and in use?
I have no actual use of the SRX828, but the drivers it uses are not as good as the neodymium magnet structure differential drive drivers in the SRX728, and have no more Xmax, so from a technical standpoint the SRX828 are a step down, not up.

And the SRX peak figures are hogwash, but industry standard hogwash.

Here is an explanation of how the hogwash works:
David Gunness wrote on 4/10/14, post # 18:

https://soundforums.net/threads/9905-Compact-Power-Subs-for-Stick-mains

"OK, here we go. Once more into the breach. The reason I hate this is that in the process of explaining how our industry does specs, it appears that I am justifying practices that I actually don't agree with.

One of the reasons I don't like peak SPL specs is that "SPL", at least in textbooks, is defined as the RMS sound pressure (referenced to 2x10-5 pascals). So theoretically, there is no such thing as "peak SPL". OK, maybe that's too pedantic: we could interpret it as "peak sound pressure, expressed in units of SPL". Let's go with that.

The point is that "Peak SPL" as it is treated in the professional loudspeaker industry, is peak pressure, not "highest reading of an SPL meter" (SPL meters only measure RMS; even if there is a peak hold function, it is the "highest rms reading observed", and that includes the selected averaging time). Anyway, peak pressure is calculated using the peak voltage of the amplifier. With non-powered systems, the assumption is that a user will supply an amplifier with twice the power rating of the loudspeaker, and that the peak voltage of the amplifier is 3 dB higher than that, because amplifiers are rated with sine waves. Hence, the peak pressure should be 6 dB higher than the maximum continuous SPL.

Keep in mind that maximum continuous SPL is a survival rating, not a useability rating. Of course what would be more useful is "maximum useable SPL", but that would be signal dependent and would have to be subjectively determined. So we're stuck with a calculated value that serves only as a point of comparison: "This one's red line is 2 dB higher than this one's red line."



Art
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Mark Wilkinson on October 20, 2016, 10:35:20 am
So my real question from all of this: do I keep my iTech 8000s and SRX728s ?
I am currently debating between buying another pair of 728s ....
I currently have 4 SRX728s and 3 iTech 8000s so I could easily add another pair of subs off of the 3rd iTech.


That's what I'd do, for sure....too easy and low $ vs cost of a lateral change...
I could see a jump to TH-118's or Orbit Shifters or something in that vein, but why spend very much money for any move less than that..

Here's a good review of the 800 series, that you'll need to put in google translate..http://www.production-partner.de/test/jbl-srx-800-im-test/
It's mostly about the 835 and 815, but it does provide some info about the 828..


edited for more clarity
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on October 20, 2016, 09:25:10 pm
That's what I'd do, for sure....too easy and low $ vs cost of a lateral change...
I could see a jump to TH-118's or Orbit Shifters or something in that vein, but why spend very much money for any move less than that..

Here's a good review of the 800 series, that you'll need to put in google translate..http://www.production-partner.de/test/jbl-srx-800-im-test/
It's mostly about the 835 and 815, but it does provide some info about the 828..


edited for more clarity

Thanks Art and Mark! I agree that I will probably just stick to the 728s and just add more.
Now to get the limiter settings dialed in! If anyone has any advice here, I would be very grateful. I've been reading a lot on the subject and scoured the Internet quite a bit and all I seem to find is conflicting information. I have even contacted JBL Pro and Crown to no avail. The person at JBL Pro gave me peak voltage based on the 3200 watt continuous rating and 3.1 min ohm and the outcome was very different than what was previously mentioned in this post and also was different than a post I found on a crown forum where the peak voltage was 140v (which would put peak wattage at 4900 if I am correct). I also found another Crown tech saying it should be 113v. Crown tech support has yet to contact me back from posts on their site and submitting contact forms. The same forum showed that the RMS limiter should be set to 400watts which doesn't make sense to me if the actual continuous rating is 1600watts. Another thing I am shaky on is the attack and release time for both peak voltage and RMS. Clearly I have a lot to learn. Any wisdom/clarification on the subject would be much appreciated.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Ivan Beaver on October 20, 2016, 09:47:49 pm
Thanks Art and Mark! I agree that I will probably just stick to the 728s and just add more.
Now to get the limiter settings dialed in! If anyone has any advice here, I would be very grateful. I've been reading a lot on the subject and scoured the Internet quite a bit and all I seem to find is conflicting information. I have even contacted JBL Pro and Crown to no avail. The person at JBL Pro gave me peak voltage based on the 3200 watt continuous rating and 3.1 min ohm and the outcome was very different than what was previously mentioned in this post and also was different than a post I found on a crown forum where the peak voltage was 140v (which would put peak wattage at 4900 if I am correct). I also found another Crown tech saying it should be 113v. Crown tech support has yet to contact me back from posts on their site and submitting contact forms. The same forum showed that the RMS limiter should be set to 400watts which doesn't make sense to me if the actual continuous rating is 1600watts. Another thing I am shaky on is the attack and release time for both peak voltage and RMS. Clearly I have a lot to learn. Any wisdom/clarification on the subject would be much appreciated.
There are a number of different "correct" limiter voltages.

Which one depends on how you run the system, type of music, how many limiters you have available, what parameter are available within the limiters etc.

Some times setting it for 1/4 continuous power is wise.  Other time setting it 8 times higher (peak power) is correct.

There is no simple single answer-but rather one that depends on a number of different variables.

Without knowing all the variables, it is nothing but a wild guess as to what would be proper for you.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on October 20, 2016, 10:16:21 pm
There are a number of different "correct" limiter voltages.

Which one depends on how you run the system, type of music, how many limiters you have available, what parameter are available within the limiters etc.

Some times setting it for 1/4 continuous power is wise.  Other time setting it 8 times higher (peak power) is correct.

There is no simple single answer-but rather one that depends on a number of different variables.

Without knowing all the variables, it is nothing but a wild guess as to what would be proper for you.

Sorry, Ivan, I thought I had specified more. I am using Crown iTech 8000s (so limiters are peak voltage and RMS with attack and release times on each). Running 1 amp per 2 subs at 4ohms a channel. 4 subs total at present. I am either doing live music or EDM at most events these days. The specific event I am gearing up for is an EDM show and I want to make sure that I have my gear set to get the most out of it but also be protected. This will pretty much be my first gig using all 4 subs since having the iTechs and I previously had XTi amps which did not really have limiters worth using. So I am trying to make sure that I have the correct understanding of what I should expect to see from both the amps, speakers and limiters. Not really having used limiters before I am weary of how far to push things and if I am ok running into limit and if I do, how much is ok?

I hope this provides some more needed info! Any help on the subject is much appreciated :)
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Ivan Beaver on October 21, 2016, 09:47:58 am
Sorry, Ivan, I thought I had specified more. I am using Crown iTech 8000s (so limiters are peak voltage and RMS with attack and release times on each). Running 1 amp per 2 subs at 4ohms a channel. 4 subs total at present. I am either doing live music or EDM at most events these days. The specific event I am gearing up for is an EDM show and I want to make sure that I have my gear set to get the most out of it but also be protected. This will pretty much be my first gig using all 4 subs since having the iTechs and I previously had XTi amps which did not really have limiters worth using. So I am trying to make sure that I have the correct understanding of what I should expect to see from both the amps, speakers and limiters. Not really having used limiters before I am weary of how far to push things and if I am ok running into limit and if I do, how much is ok?

I hope this provides some more needed info! Any help on the subject is much appreciated :)
As a side note-I often respond with questions that may not be specific to the particular question, but rather so that others might learn as well and get a better understanding to their systems, which might be different than the actual system in question.

This forum is about learning and sharing information as well as getting specific answers.  At least I feel that way.


Anyway, Since you are using all Harmon gear-why no use their presets?  I would think that would be a good starting point.

But based on your answers, I would set the thermal limiter to around 1/4 to 1/3rd the continuous rated power.

I would set the continuous limiter for the continuous rated power.  This is not the "program" power rating.

The peak is up for debate, but in my opinion, especially with "abusive" music styles, I often set my peak power for either the limit of the amp or the program rating of the loudspeaker-whichever is lower.

The extra 3dB that you could possibly get is simply not noticeable and the average "event goer" will not realize it, but that extra power could put some additional strains on your speakers-not so much in term of power, but rather in terms of excursion.

I believe the Itechs also have a "amp clip eliminator" that is not located in the limiter sections, but rather in the "amp" section or an output block.  I don't remember exactly as it has been awhile since I was inside one.

I would always turn that ON (there are no adjustments-just on or off), no matter what.  The extra dB or so that you might get out of the amp with it off is simply not worth the possible extra distortion that you might get.

I am a firm believer that if any amp offers clip protection, then ALWAYS use it.

It offers one more level of protection.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on October 27, 2016, 02:03:56 pm
As a side note-I often respond with questions that may not be specific to the particular question, but rather so that others might learn as well and get a better understanding to their systems, which might be different than the actual system in question.

This forum is about learning and sharing information as well as getting specific answers.  At least I feel that way.


Anyway, Since you are using all Harmon gear-why no use their presets?  I would think that would be a good starting point.

But based on your answers, I would set the thermal limiter to around 1/4 to 1/3rd the continuous rated power.

I would set the continuous limiter for the continuous rated power.  This is not the "program" power rating.

The peak is up for debate, but in my opinion, especially with "abusive" music styles, I often set my peak power for either the limit of the amp or the program rating of the loudspeaker-whichever is lower.

The extra 3dB that you could possibly get is simply not noticeable and the average "event goer" will not realize it, but that extra power could put some additional strains on your speakers-not so much in term of power, but rather in terms of excursion.

I believe the Itechs also have a "amp clip eliminator" that is not located in the limiter sections, but rather in the "amp" section or an output block.  I don't remember exactly as it has been awhile since I was inside one.

I would always turn that ON (there are no adjustments-just on or off), no matter what.  The extra dB or so that you might get out of the amp with it off is simply not worth the possible extra distortion that you might get.

I am a firm believer that if any amp offers clip protection, then ALWAYS use it.

It offers one more level of protection.
Thanks for the info! I didn't realize the iTechs had that clip protection. It is now enabled on all my amps.

As for the presets, I have yet to find a preset that actually includes limiter settings. I have only found tunings from JBL and the support person I spoke with didn't have any info limiter settings and said to contact Crown (whom I have yet to hear from).

I have not seen a thermal limiter in the 8000. Or least not one that can be set.
As for the continuous RMS limiter, I found that having it at 1600 watts (the continuous rating of the speaker) that I wasn't even hitting the limiter section but was clipping the input before the limiter on the output. (I had to put the sensitivity to the +37db if I recall correctly). When I put the RMS limiter to 800watts then it was actually doing some limiting. Am I missing something? Seems like I should be able to get more out of it than that.

I had the peak voltage set to the level I had seen posted on a Crown forum to 140v. From your recommendation it sounds like I should set it to 99.599v.

Attached is a formula I was provided on this forum. According to that, the Vrms is what you recommend for me to set the peak voltage to, correct?

Thanks again for all your wisdom and advice!
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: David Sturzenbecher on October 27, 2016, 07:40:06 pm

I have not seen a thermal limiter in the 8000. Or least not one that can be set.
As for the continuous RMS limiter, I found that having it at 1600 watts (the continuous rating of the speaker) that I wasn't even hitting the limiter section but was clipping the input before the limiter on the output. (I had to put the sensitivity to the +37db if I recall correctly). When I put the RMS limiter to 800watts then it was actually doing some limiting. Am I missing something? Seems like I should be able to get more out of it than that.



If you look closely at the "RMS Power" limiter in the original iTech, you will see that the shortest that the attack time can be set to is 1sec.    That is far too slow for an RMS limiter as talked about on this forum.    A limiter with an attack time of 1 second or longer really falls into the "thermal" limiting realm.

With an itech, it's a ok idea to ignore the peak limiter, as there is a good chance the peak power capability of the speaker is far above what the amp can produce (especially on subs), then place the itechs "peak voltage" limiter to cover what would typically be the RMS limiting functions, and then use the "RMS power" limiter for thermal limiter duties as described above. 

Another note, if you are clipping your amp input before reaching full amplifer output (common with internal amplifier crossovers)  simply add more "bandpass gain".   Don't be afraid to add 10dB or more if needed.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Ivan Beaver on October 27, 2016, 08:05:23 pm
 I would set the "long term" limiter (RMS or thermal or whatever it is called) at around 1/3rd the constant power.

I would set the "program or  average or whatever" at the constant power.

Then the peak at the peak-or a little lower.

As David said-don't be afraid to add some gain inside the amp.

I have noticed that often the input overloads before hitting the limiters-especially when used on subs
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on October 28, 2016, 04:15:21 pm
I would set the "long term" limiter (RMS or thermal or whatever it is called) at around 1/3rd the constant power.

I would set the "program or  average or whatever" at the constant power.

Then the peak at the peak-or a little lower.

As David said-don't be afraid to add some gain inside the amp.

I have noticed that often the input overloads before hitting the limiters-especially when used on subs

Thanks so much for the info! One question I have is if I take David's method of using the peak limiter in the iTech for RMS limiter and the RMS limiter for the thermal limiter, will that affect the actual peak output? (Because then the amp will only be giving 3200 watts max to the sub, right?) Please forgive my ignorance on the subject.

I am attaching a pic of what I believe would be the correct settings based on Ivan and David's info. The only question I now have is what I should be setting the attack and release times to (seeing as I am using the limiters for something differently than maybe initially intended). And what would I set the peak limiter to if I was still using the actual peak voltage of 140v? I have read some documentation from powersoft on limiter settings but am unsure of what to set attack and release time for the different types of limiters. Any help would be much appreciated!
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Ivan Beaver on October 28, 2016, 04:49:53 pm
Thanks so much for the info! One question I have is if I take David's method of using the peak limiter in the iTech for RMS limiter and the RMS limiter for the thermal limiter, will that affect the actual peak output? (Because then the amp will only be giving 3200 watts max to the sub, right?) Please forgive my ignorance on the subject.

I am attaching a pic of what I believe would be the correct settings based on Ivan and David's info. The only question I now have is what I should be setting the attack and release times to (seeing as I am using the limiters for something differently than maybe initially intended). And what would I set the peak limiter to if I was still using the actual peak voltage of 140v? I have read some documentation from powersoft on limiter settings but am unsure of what to set attack and release time for the different types of limiters. Any help would be much appreciated!
I would use the 1600 watts at the continuous rating-NOT the program rating.

So that would be 80V.  I would also change the attack time to 20-30ms.

Remember that the peaks are generally short, so they will pass before the attack time start to dramatically limit them.

You MUST weigh getting that little extra dB or so out of a cabinet-vs burning them up.

What is most important?

To me-having the cabinet working at the end of the night is MUCH more important than trying to squeeze an extra dB or so out of the cabinet-that NOBODY would every notice.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Andrew Brubaker on October 28, 2016, 05:10:43 pm
I would use the 1600 watts at the continuous rating-NOT the program rating.

So that would be 80V.  I would also change the attack time to 20-30ms.

Remember that the peaks are generally short, so they will pass before the attack time start to dramatically limit them.

You MUST weigh getting that little extra dB or so out of a cabinet-vs burning them up.

What is most important?

To me-having the cabinet working at the end of the night is MUCH more important than trying to squeeze an extra dB or so out of the cabinet-that NOBODY would every notice.

Having my gear intact at the end of the night is obviously the more important thing here. Would having the peak voltage at the program rating really be that likely to harm the subs? I appreciate your wisdom and insight on this matter, Ivan!

Please see the attached revision. Do the release and attack times for the RMS (thermal) limiter look in line with what they should be?
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: David Sturzenbecher on October 28, 2016, 05:15:43 pm
Andrew, if you look at some attack times that JBL uses on their itechHD presets for their own subwoofers, they are in the 4-7 second range. I know Ivan recommends a little shorter 1-2 seconds. Kinda all how cautious you want to be. 


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Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Ivan Beaver on October 28, 2016, 06:16:46 pm
Andrew, if you look at some attack times that JBL uses on their itechHD presets for their own subwoofers, they are in the 4-7 second range. I know Ivan recommends a little shorter 1-2 seconds. Kinda all how cautious you want to be. 


Sent from my iPhone using Tapatalk
For those woofers-I would probably go with 2-3 seconds.

Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Ivan Beaver on October 28, 2016, 06:28:04 pm
Having my gear intact at the end of the night is obviously the more important thing here. Would having the peak voltage at the program rating really be that likely to harm the subs? I appreciate your wisdom and insight on this matter, Ivan!

Please see the attached revision. Do the release and attack times for the RMS (thermal) limiter look in line with what they should be?
It is not the limiter settings that will harm the subs, but rather the program content.

For example-if you want to "squeeze every watt" out of any loudspeaker, then tell me what SONG you want to play.

I can analyze it and come up with some settings to "get the most" out of the loudspeaker.

You DO NOT get to play any other song-because the settings will be different for the different song.

Different styles put different strains on different parts of loudspeakers.

How long the system is operated and under what conditions also affects the limiter settings.

A system that is run 24hours a day for 3 days with no break MUST have lower limiter settings than one that plays for 45 minutes and takes a 15 min break.  And has breaks between songs that there is some talking.

At best-limiter setting is a guess/estimate, based on experience with a particular loudspeaker, and how a particular DSP reacts.

The limiters on different DSPs (just like the eq and crossover settings) ARE NOT the same from model to model.

It is best to "tighten up" on the limiters (setting them lower than specs would indicate)-just in case.

There is no "simple answer" to the VERY COMPLEX question of setting limiters.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Chris Grimshaw on October 31, 2016, 05:20:46 am
For example-if you want to "squeeze every watt" out of any loudspeaker, then tell me what SONG you want to play.

I can analyze it and come up with some settings to "get the most" out of the loudspeaker.


Okay, here's one that I know is particularly evil for subs (caution - NSFW lyrics): https://www.youtube.com/watch?v=UnQY3swM4tA
I believe its basically a compressed 36Hz sine wave with a peak-to-average ratio of less than 3dB.


One thing that isn't addressed is the frequency dependance of power handling. For instance, if you've got a cabinet that tunes to 36Hz and play that track, the woofer will barely be moving. Most bass drivers rely on forced air movement to keep the motor cool. No cone movement = no cooling, so now you're going to need to severely de-rate your thermal power handling.
What would you set for that track and a TH115?

For what its worth, most music isn't as bad as this. Live rock, for instance, has most of the LF power in the kick drum (ie, very peaky), so you're in more danger of over-excursion than burning the drivers.

Chris
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Ivan Beaver on October 31, 2016, 06:12:39 am

I believe its basically a compressed 36Hz sine wave with a peak-to-average ratio of less than 3dB.



What would you set for that track and a TH115?


If that is your "reference and want to reproduce the 36 Hz tone loud, then I would not use a TH115-because 36 Hz is below the -3dB point.

But if you did want to use the TH115-then I would raise the HP filter a bit to maybe 35Hz, put some out of band eq down low to get a steeper slope without as much phase shift as a steeper filter would produce.

The actual limiter settings would depend on what particular settings were available.

But if you were talking sine waves below specs, then I would go for 1/4 power.  So if using the 4 ohm version, then 31 V with a 2  second attack,  would be a good number to start with.
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Chris Grimshaw on October 31, 2016, 06:43:18 am
Hi Ivan,

I was under the impression that the TH115 has a 36Hz tuning frequency, but (as with most tapped horns I've seen) rolls off slightly before that. Perhaps the TH118, then?

Either way, just curious about how cautious you'd be with music that approximates sine waves, and the worst-case where the sine wave happens to be at a frequency where there's not much driver cooling. You've certainly tested more speakers than me, so any insight into what happens when the going gets really tough would be appreciated.

Cheers
Chris
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Ivan Beaver on October 31, 2016, 01:32:22 pm
Hi Ivan,

I was under the impression that the TH115 has a 36Hz tuning frequency, but (as with most tapped horns I've seen) rolls off slightly before that. Perhaps the TH118, then?

Either way, just curious about how cautious you'd be with music that approximates sine waves, and the worst-case where the sine wave happens to be at a frequency where there's not much driver cooling. You've certainly tested more speakers than me, so any insight into what happens when the going gets really tough would be appreciated.

Cheers
Chris
If you want to only use 1 song, then there are all sorts of options you can do for limiting-such as using a side chain on the limiter that is tuned for the "particular freq".  Actually study the freq, the durations etc in the song to get a better idea of how it would heat up and cause excursion issues.

But you would also have to study the impedance graphs of the sub, the excursion plots etc to come up with the "ultimate limiter" for that song.

But play a different song and now it is different.

So the best you can come up with is decent guess that would cover a wide range of material.

It is a waste of time trying to come up with the proper settings for one song-unless that is all you are going to play.

BTW-we do have some large systems (think multiple Jerichos for each install) and all they will ever play their entire life is part of ONE song.  Usually 30 seconds or less.

So in that case you could make the argument for spending the time.  But since they are not run at max capability, squeezing out every last dB is not that important.
Title: Re: limiters
Post by: Art Welter on October 31, 2016, 02:25:10 pm
I was under the impression that the TH115 has a 36Hz tuning frequency, but (as with most tapped horns I've seen) rolls off slightly before that. Perhaps the TH118, then?
Chris,
Both TH-115 and 118 are basically the same box, with the same Fb. At Fb, the excursion is at minimum as well as the impedance being at minima.

Therefore, the driver consumes the most power at the frequency where there is the least cooling- the coil is not pumping the heat out of the magnet assembly like it will just 1/3 octave above Fb where excursion is greatest, but impedance much lower.

Since the TH power specs are just reprints of the AES driver free-air rating based on a nominal 4 ohm driver with a given voltage (not wattage), the actual in-cabinet power dissipation due to the much lower impedance of the TH loading is much greater, hence Ivan's  advice "if you were talking sine waves below specs, then I would go for 1/4 power".

Otherwise, it's like the old song:
"Burn, baby Burn,
Disco Inferno"


Cheers,
Art
Title: Re: JBL's New SRX800 Series Subs - How do they compare?
Post by: Chris Grimshaw on December 12, 2016, 07:51:35 am
That's what I'd do, for sure....too easy and low $ vs cost of a lateral change...
I could see a jump to TH-118's or Orbit Shifters or something in that vein, but why spend very much money for any move less than that..

Here's a good review of the 800 series, that you'll need to put in google translate..http://www.production-partner.de/test/jbl-srx-800-im-test/
It's mostly about the 835 and 815, but it does provide some info about the 828..


edited for more clarity

Just read through that. Thanks for the great link.
I'm going to see if I can do some similar testing with my own speakers - with all the unobtainable max.SPL figures that manufacturers are pushing out, having some solid numbers (this box will produce this SPL in this range with a maximum of 10% THD) is really useful to compare.

Cheers
Chris