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Church and H.O.W. Forums for HOW Sound and AV - Your Displayed Name Must Be Your Real Full Name To Post In The Church and HOW Forums => Church Sound => Topic started by: Trevor Crowe on February 07, 2016, 04:31:43 pm

Title: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 07, 2016, 04:31:43 pm
Hi All,
I just wanted to share my experience with our new JBL SRX835p pair.

For reference, our church is a 500 seat auditorium with corner stage in a big square layout.

Our previous speakers were 4 QSC K12's spread across the bulkhead. The reason we switched was the QSC's struggled in the midrange clarity when pushed. They were great for low level, but that was it. We rarely go over 90db.

My theory was that a 3 way would provide better midrange clarity by having a dedicated driver for mostly vocals, while it frees the woofer to only have to go up to 500hz and the compression driver only has to do 2khz and up. Also, the drivers are working in their optimal bandwidth, so dispersion is very even at 60 deg.

By clustering 2 to cover 120 deg, the sound is very even across the room, and cuts off sharply near the walls.

The result so far is superior vocal clarity. Which is important for the sermon and worship music. A surprise bonus is amazing mid bass that the QSC's couldn't do. The JBL's have a nice hump around 60-120hz, where the dual 18" sub on the floor and take over the 40-80hz range. So the bass actually sounds like its coming from the mains which is nice.

I'm a little dissappointed by the highs, even after alot of EQ'ing. They don't seem to extend to the extreme top end. I was hoping for a little more 'delicacy' and detail in the highs, but maybe they just need some break in hours?

So the speakers can effortlessly project 100+db volumes for such a large auditorium. I'm very impressed. With the trade in on the 4 QSC's, the $2000 difference made a huge improvement.

I will post an update after our service tomorrow. (Mostly rock type worship)
(http://uploads.tapatalk-cdn.com/20160207/7870e43805def5c2eeb619a06a1cbb8e.jpg)(http://uploads.tapatalk-cdn.com/20160207/eb739562e089cd38353b56688b92796f.jpg)(http://uploads.tapatalk-cdn.com/20160207/d0252c14e8cb4c9b616a21dcc9a01fb8.jpg)
Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Holtzman on February 07, 2016, 11:40:11 pm
I am sure some more knowledgeable riggers will comment,  some safety issues with your flying if my eyeballs serve me right.

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Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Carneval on February 08, 2016, 12:04:10 am
It looks like you have both speakers pointing straight ahead and not splayed. That will affect the HF as you've described.

Is that dog chain rated for overhead lifting?


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EDIT: After looking at this again on my computer, it looks like the speakers are splayed a little bit. I haven't used the 835 but I did get some hands-on time with the 815, and I thought the HF was a little bright for my taste. This was pre-recorded playback, so if you're using live instruments your mileage may vary. Are you not getting enough HF, or do you just not like the way it sounds? Have you noticed this 'issue' in several spots throughout the venue or were you listening in just one spot?

I also missed this on my phone...the load is suspended at a 90 angle on the eyebolts. This reduces their Working Load Limit considerably. Some manufacturers go so far as to forbid loading at 90, while others reduce the rating by as much as 80%. I'm not saying they can't safely be suspended this way, but I hope you got the rig certified by a structural engineer. This is a life safety issue and is not to be taken lightly. That's a 300lb speaker array and it will kill someone if it falls on them.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Irvin Pribadi on February 08, 2016, 11:20:00 am
From the way it is splayed, I can imagine the front rows would miss out on some HF.

How was the splay angle determined?
Title: Re: JBL SRX835p for FOH Mains review
Post by: David Allred on February 08, 2016, 12:51:03 pm
A question to smart folks.
With the 2 cabs strapped together with angle iron (top & bottom), is the center rigging supporting a 1/3 share (100 lbs) or a 1/2 of each cab share (150 lbs)?  I say the latter, unless the angle iron went all the way across and serves as the suspender.  Am I correct?
Best safe practice is to have each rigging point capable (rated) of 300 lbs min.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 08, 2016, 05:11:51 pm
The speakers are 85lbs each. It was reviewed and approved by two different engineers.

The speakers are splayed just enough to avoid a dead spot. The specs show about 30deg per side, so they are about that, maybe less. I played with them on the stage and got the angle right before hoisting using RTA. The despersion is very even both vert and horz. But there is a dead spot to the far right for about 10 seats total. We were considering adding a 3rd to the cluster but that would provide too much hitting the side walls.

Anyway, I'm more concerned about the highs. It's not an EQ thing, but quality. I was expecting more refinement. I'm an audiophile and have Altec Vott with tube power at home, so that is my reference. Is it just that the newer higher power handling stuff compromises on quality? (Stiffer sourrounds, heavier cones, plastic horns, etc)
I bypassed the DBX 260 to see if it was the culprit, and even hooked my laptop directly to the speakers, and the highs are the same- somewhat shrill and harsh sounding in the 2kz-20khz. This is both live, and recorded mastered live stuff.


Title: Re: JBL SRX835p for FOH Mains review
Post by: Irvin Pribadi on February 08, 2016, 11:25:56 pm
Well in that case it may just be the speakers. idk I don't have experience with JBL 800 series.
If you like try powering and listening to just one speaker at a time to see the issue is repeated by each speaker independently at low to moderate volumes.
You can also run a measurement just to see if there is no narrow spike or dip in the frequency response that can be fixed.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Holtzman on February 08, 2016, 11:42:55 pm
Well in that case it may just be the speakers. idk I don't have experience with JBL 800 series.
If you like try powering and listening to just one speaker at a time to see the issue is repeated by each speaker independently at low to moderate volumes.
You can also run a measurement just to see if there is no narrow spike or dip in the frequency response that can be fixed.

Since the speakers are not splayed very much you have a lot of destructive interference in the overlap zone.  That could be zapping your HF response.

Just what measurement did you obtain with the RTA and how did you apply that to your positioning of the speakers or adjustment of the system?

Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 09, 2016, 08:12:13 am
Here is the gated response I did at 1m using REW and MiniDSP Umic with cal file. As you can see the 3 way has a pretty narrow beam width compared to the more traditional 2 ways. (60 deg vs 90) So I believe the splay is correct. Any more, and there was an audible hole in the centre isle.
I've tried to bring up the dip at 2.5k and drop the peak at 12k. But that 12k peak could be the culprit. This week I intend to RTA and EQ around the room with my mic and laptop, and get it flatter. This is using the DBX 260, but I wondering if I would get better results with the new JBL iPad app for EQ, Just need to run a network cable up to the speakers.
Keep you posted.
(http://uploads.tapatalk-cdn.com/20160209/e7fa06386be30186586ae62585352552.jpg)
Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Carneval on February 09, 2016, 09:07:08 am
The speakers are 85lbs each. It was reviewed and approved by two different engineers.

You've also got the weight of the hardware, which probably isn't much, but then the weight of the chain, which will be a considerable amount. If it's lightweight chain it's probably not rated. If it's rated chain it's probably not lightweight. Not trying to bust your balls here, but this isn't something to be taken lightly (pun not intended). If an engineer certified the rig, fine, but it needs to be mentioned for the sake of others reading this post.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Carneval on February 09, 2016, 09:16:52 am
Here is the gated response I did at 1m using REW and MiniDSP Umic with cal file. As you can see the 3 way has a pretty narrow beam width compared to the more traditional 2 ways. (60 deg vs 90) So I believe the splay is correct. Any more, and there was an audible hole in the centre isle.
I've tried to bring up the dip at 2.5k and drop the peak at 12k. But that 12k peak could be the culprit. This week I intend to RTA and EQ around the room with my mic and laptop, and get it flatter. This is using the DBX 260, but I wondering if I would get better results with the new JBL iPad app for EQ, Just need to run a network cable up to the speakers.
Keep you posted.
(http://uploads.tapatalk-cdn.com/20160209/e7fa06386be30186586ae62585352552.jpg)

That dip you're seeing is probably a cancellation due to either a reflection (maybe off of the metal ceiling) or interference from the other box. You said you got a hole when you splayed them further than 30 degrees...could it have been cancellation causing a dip in HF instead? Are they splayed 30 total, or 30 per box?

RTA is really not the correct tool for this. You need a multi-channel measurement system so you can run a transfer function.
Title: JBL SRX835p for FOH Mains review
Post by: Samuel Rees on February 09, 2016, 09:33:16 am
Multichannel measurement is definitely recommended here rather than an RTA. Try using level measurement to determine the splay angle and see what that comes up with compared to what you have now. Measure one box out to -6 and then place and measure the other box such that it reaches -6 at the same spot. You may be splaying them too narrow in an attempt to get perfect coverage in the overlap area which isn't really going to happen when splaying two fairly wide boxes. I think the reason everyone here suspects splay is the boxes look pretty close in the pictures and too much overlap could very easily produce unappealing peaks and valleys in the high frequency, which fits your complaint well.

My other thought is that your preferences based on your home listening environment don't necessarily correlate to a specific measurement or tuning outcome. If you like more HF, add it, or don't.
Title: Re: JBL SRX835p for FOH Mains review
Post by: David Sturzenbecher on February 09, 2016, 10:15:21 am
The OP should also post back if he like the HF of just one box, and if it gets worse or better with the second box turned on.


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Title: Re: JBL SRX835p for FOH Mains review
Post by: Cailen Waddell on February 09, 2016, 01:27:45 pm

You've also got the weight of the hardware, which probably isn't much, but then the weight of the chain, which will be a considerable amount. If it's lightweight chain it's probably not rated. If it's rated chain it's probably not lightweight. Not trying to bust your balls here, but this isn't something to be taken lightly (pun not intended). If an engineer certified the rig, fine, but it needs to be mentioned for the sake of others reading this post.

And to further play devils advocate - engineered drawing or not, if you use a manufacturers product in a way other than it was designed and it fails... Good luck with any liability suit against the manufacturer for a failure of their product.


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Title: Re: JBL SRX835p for FOH Mains review
Post by: Jonathan Johnson on February 09, 2016, 01:52:47 pm
The speakers are 85lbs each. It was reviewed and approved by two different engineers.

Was the review of the design or of the installation? Did the review include the mounting to the structural steel? Was the hardware used as specified by the engineer? Not all eye bolts are created equal.

What stands out to me is the eye bolt going into the side of the roof purlin. It appears that most of the force is downward, meaning that there is a bending moment on the shaft of the bolt. This places a twisting force on the purlin; the force on the purlin is not evenly distributed around the hole, but rather is concentrated at the top (outward) and bottom (inward) with almost no force applied at the sides.

From my non-engineer "armchair engineering" viewpoint, I would have expected to see the eye bolt inserted into the flange of the purlin, placing the stress more axially along the bolt shaft rather than radially as it is now. It appears that all other suspended items are supported by the flange rather than the side of the purlin.

The rule-of-thumb margin of safety for overhead suspended loads is 10:1. (For loads not suspended overhead, it's generally 3:1.) If your load is 180 pounds (170 pounds for speakers plus another 10 for hardware), the suspension system must be rated for 1800 pounds. The failure of a single link should not result in catastrophic failure resulting in collapse. The loads need to be analyzed to determine the dynamic loading (including angles, which will change in a failure) on the other links should any one fail.
Title: Re: JBL SRX835p for FOH Mains review
Post by: David Allred on February 09, 2016, 03:54:13 pm
For load rated hardware a design factor of (typically) 4x is used.  Meaning that an eye-bolt with a SWL, WLL, SL, etc of 400 lbs will not fail until 1600 lbs (if used properly).  I am not suggesting going beyond 400 lbs, but rather that 400 lbs is guaranteed (and twice on Sundays).  90 degrees loads on eyebolts is outside their design parameters.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 09, 2016, 05:05:46 pm
There are 5 mounting points. The eyebolts are m10 mcmaster carr rated at 1600 lbs verticle. Assuming 20% for side load that is 360lbs each. 170lbs total divided by the 3 main front mounts(the 2 back are mainly for tilting). But I do agree, they should have been mounted on the bottom of the flange, with 2" washers on both sides.
Title: Re: JBL SRX835p for FOH Mains review
Post by: g'bye, Dick Rees on February 09, 2016, 05:05:54 pm
Agreed. 

Sound here is WAAAY down the list after dealing with the safety (and liability) issues. 

First:  make it safe
Second:  make it safe
Third:  make it safe

Edit:

Chain is not acceptable for flying loads overhead.

Where are the safeties?
Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Carneval on February 09, 2016, 05:53:55 pm
There are 5 mounting points. The eyebolts are m10 mcmaster carr rated at 1600 lbs verticle. Assuming 20% for side load that is 360lbs each. 170lbs total divided by the 3 main front mounts(the 2 back are mainly for tilting). But I do agree, they should have been mounted on the bottom of the flange, with 2" washers on both sides.

McMaster Carr rates their M10 eyebolts for up to 45 side loading. They are also de-rated to 20% at 45.

http://www.mcmaster.com/#eyebolts/=111zhgo

20% of 1600 is 320lbs.

You're still forgetting to include the weight of the hardware, as it is also suspended from the eyebolts.

I looked on the JBL website and my 01/2016 JBL dealer price sheet, I don't see any sort of splay/cluster brackets available for the SRX835. Did the ones in your picture come from JBL? If not, do they have a PE stamp?







Title: Re: JBL SRX835p for FOH Mains review
Post by: Jonathan Johnson on February 09, 2016, 06:14:16 pm
Quote from: everybody
...blah blah engineering blah blah...proper rigging...blah blah...life safety...blah blah

Lest you get discouraged, please understand that the folks here want you to have a safe installation above all else. We're happy to help, but anything that looks like a potential physical hazard WILL get addressed before any technical issues.

Of course, no one here can MAKE you do things right; we just want to make sure you to understand the risks of not doing things right. We're also trying to help you make wise judgement so you, yourself can be better able to spot when something's not right.

Sometimes it seems the folks here are hard on newbies. Try not to take it personally. Take heart, we really DO want you to get the best sound possible out of your system. Safely.

But if you refuse to acknowledge unsafe situations, then you will receive no mercy.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 09, 2016, 07:58:49 pm
Guys, the engineers who designed the building reviewed and approved it. (Bel Con Engineering)
I guess I could get them to take a 2nd look based off the comments regarding the eye bolts.
Title: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 09, 2016, 08:13:30 pm
I've put in a request to have the engineers take a second look. Based on the comments I said the eye bolts shouldn't be loaded sideways. I'm persoanally not worried so much about them breaking, but the torque of them pulling out of the galvenized trusses. I recommended they be moved on saturday to the bottom of the truss with thick 2" washers and vertical loading, and then have the PE sign off in writing.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Irvin Pribadi on February 10, 2016, 12:18:20 am
Good move on bringing the engineer back and fix things.

For the REW measurements you intend to do, make comparisons between one, the other and both speakers powered on at a few set distances along the center aisle. This should reveal any splay angle concerns.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Carneval on February 10, 2016, 09:49:35 am
I've put in a request to have the engineers take a second look. Based on the comments I said the eye bolts shouldn't be loaded sideways. I'm persoanally not worried so much about them breaking, but the torque of them pulling out of the galvenized trusses. I recommended they be moved on saturday to the bottom of the truss with thick 2" washers and vertical loading, and then have the PE sign off in writing.

Trevor,

I'm glad to hear you're taking this seriously. If the engineers did in fact design this rig, and it was done exactly as they specified, then they should be liable for whatever costs are incurred to correct it.

Title: Re: JBL SRX835p for FOH Mains review
Post by: Ryan Detlefsen on February 10, 2016, 12:47:48 pm
I just installed them as mains as well with the dual 18" on the floor in a small bar.  Sound is amazing.  These things rock(http://uploads.tapatalk-cdn.com/20160210/2e1b2ee0b59b5730a00bdef11d12ad86.jpg)(http://uploads.tapatalk-cdn.com/20160210/b2ceb56021cd0eba459d48cb17bb0943.jpg)


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Title: Re: JBL SRX835p for FOH Mains review
Post by: Doug Fowler on February 10, 2016, 01:16:19 pm
I just installed them as mains as well with the dual 18" on the floor in a small bar.  Sound is amazing.  These things rock(http://uploads.tapatalk-cdn.com/20160210/2e1b2ee0b59b5730a00bdef11d12ad86.jpg)(http://uploads.tapatalk-cdn.com/20160210/b2ceb56021cd0eba459d48cb17bb0943.jpg)


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Read the rules, fix your display name.

Thank you for your cooperation.
Title: Re: JBL SRX835p for FOH Mains review
Post by: g'bye, Dick Rees on February 10, 2016, 06:01:46 pm
I just installed them as mains as well with the dual 18" on the floor in a small bar.  Sound is amazing.  These things rock(http://uploads.tapatalk-cdn.com/20160210/2e1b2ee0b59b5730a00bdef11d12ad86.jpg)(http://uploads.tapatalk-cdn.com/20160210/b2ceb56021cd0eba459d48cb17bb0943.jpg)


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I can't tell much from the photo, but those don't look to be 835's and if they are it looks pretty ridiculous for the apparent size and orientation.

Are you sure those are the right pics?
Title: Re: JBL SRX835p for FOH Mains review
Post by: Kent Thompson on February 10, 2016, 09:13:15 pm
I just installed them as mains as well with the dual 18" on the floor in a small bar.  Sound is amazing.  These things rock(http://uploads.tapatalk-cdn.com/20160210/2e1b2ee0b59b5730a00bdef11d12ad86.jpg)(http://uploads.tapatalk-cdn.com/20160210/b2ceb56021cd0eba459d48cb17bb0943.jpg)


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Its a matter of reference. Compared to what?
Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 11, 2016, 09:23:06 am

Quote
I can't tell much from the photo, but those don't look to be 835's and if they are it looks pretty ridiculous for the apparent size and orientation.

Are you sure those are the right pics?

Man you guys are nasty to newcomers. You wouldn't say that in person, or maybe you do, in which case, I rest my case.

That setup looks awesome. Congrats on your new 835's.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Cailen Waddell on February 11, 2016, 10:34:59 am

Man you guys are nasty to newcomers. You wouldn't say that in person, or maybe you do, in which case, I rest my case.

That setup looks awesome. Congrats on your new 835's.

The orientation is non-typical.  Doesn't mean it doesn't work, just different than what you usually see.  I'm sure people are interested in how the orientation was chosen, was it modeled, what the measured response is like in the room, etc.


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Title: Re: JBL SRX835p for FOH Mains review
Post by: Guy Graham on February 11, 2016, 10:41:47 am
Man you guys are nasty to newcomers. You wouldn't say that in person, or maybe you do, in which case, I rest my case.

That setup looks awesome. Congrats on your new 835's.

If someone told me they were 835s in person, I would ask why they don't look like that particular cabinet?

If I saw that room, I would query the unusual setup and in particular the potential acoustic problems.

I wouldn't say these things rudely, but they're pretty obvious points for anyone with an inquisitive mind.



Sent from my GT-I8160

Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Hofmann on February 11, 2016, 11:07:54 am
Agreed. 

Sound here is WAAAY down the list after dealing with the safety (and liability) issues. 

First:  make it safe
Second:  make it safe
Third:  make it safe

Edit:

Chain is not acceptable for flying loads overhead.

Where are the safeties?

If chain is not acceptable for flying loads overhead, what do you make of chain motors for arena rigging and trim chains on theatre battens?
Or did you mean to say that the chain as pictured is not acceptable?
Title: Re: JBL SRX835p for FOH Mains review
Post by: g'bye, Dick Rees on February 11, 2016, 11:18:32 am
If chain is not acceptable for flying loads overhead, what do you make of chain motors for arena rigging and trim chains on theatre battens?

I believe there are several issues here:

APPROVED chain is OK for lifting, but I believe once the load is in place there needs to be additional suspension and safeties in place to bear the load.

The chain in the picture appears to be plain old hardware store chain which should have a label on it stating "not for overhead lift".  The point is, it's worth checking.

Lastly, I've seen "engineering firms" do the most outrageous stuff.  One, when called back to add safeties to an un-rated OSB box suspended by plain old eye bolts in the SIDES of the cabinet,  simply added hardware store chain looped through the handles of the cabinet. 

I would suggest the OP have their insurance company verify anything these engineers are approving.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Jamin Lynch on February 11, 2016, 11:43:32 am
Disclaimer: I'm not a professional rigger.

I've read, devices designed for lifting loads, such as chain hoists,  must use load rated grade 8 chain.

I believe load rated grade 5 chain is ok for static loads.

Maybe a pro rigger will school us.

I would argue properly rigged chain and suspension hardware for a static speaker suspension would be safer than cable. I've seen one fail before.
Title: Re: JBL SRX835p for FOH Mains review
Post by: David Allred on February 12, 2016, 06:47:12 am
If someone told me they were 835s in person, I would ask why they don't look like that particular cabinet?

If I saw that room, I would query the unusual setup and in particular the potential acoustic problems.



Sent from my GT-I8160

Looks to be horns in.  More energy on the floor (people) than on the walls.  Given the box (room) probably the most advantageous.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Guy Graham on February 12, 2016, 01:03:46 pm
Looks to be horns in.  More energy on the floor (people) than on the walls.  Given the box (room) probably the most advantageous.

Apologies - I clearly posted in haste. I couldn't see key details on my phone, such as the SRX8xx characteristic cabinet shape.

Whilst JBL don't specify how wide a frequency bandwidth the 60 x 40 pattern control covers, I guess that deployment and with those mounting points in that room, is probably the best - given the limited information we have to go on.

From the details on their website, I think JBL have been remarkably clever with the SRX835p loudspeaker. They might have used the unpowered STX835 as a platform, with a rotatable mid / high section providing increased versatility, when mounted in different orientations.

However the powered box really saves a lot of weight: 38.6kg, vs 58.1kg for the more expensive and unpowered STX alternative!

Looking at the specs - JBL appear to have done something quite impressive, way beyond any phenomenal weight-saving achievement. Of course one assumes that in good faith, their specs are all true, and of course are all measured consistently across their different product lines (to allow potential customers to make fair and valid comparisons).

The quoted peak SPL figure for the STX835 is 134dB. The cheaper powered SRX835p is rated at 137dB peak SPL. Increased output capability, whilst decreasing many beneficial metrics.

If we assume JBL flattered the STX specs by measuring when biamped with ideal iTech HD power amps - the powered SRX box manages to get louder whilst also getting lighter and using fewer drivers.

In that light, the lack of facility to rotate the mid and high driver sections can surely be forgiven?

Likewise the SRX828p has benefited from a similar witchcraft-like sprinkling of JBL magic. Not only is the powered box cheaper than the STX equivalent, it goes down lower, is lighter and has a peak rated SPL that is 3dB higher!

Having glanced at the dimensions, I think JBL haven't just beaten their own competition - they're going after Hoffman's iron law as well...


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Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 12, 2016, 06:16:28 pm
I personally didn't take the claimed 137db rating very seriously. This weekend I will tweak the onboard DSP and see if I can remove the harsher highs. It's likely just a break in issue as well. That said, the 3 way clarity in the midrange is phenonminal. It went way beyond volumes the old 4 QSC K12's could do with no sign of compression.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Ivan Beaver on February 12, 2016, 07:39:38 pm
I personally didn't take the claimed 137db rating very seriously. This weekend I will tweak the onboard DSP and see if I can remove the harsher highs. It's likely just a break in issue as well.
You must remember that the "peak" rating is just that. And at 1M

Average music has a dynamic range of 15dB or so.

So when any loudspeaker is producing "peak" output, the average SPL you would measure or perceive is quite a bit lower.

And then as you get a little bit away-the level drops even more.  33' is a 20dB loss.

So running at maximum output and you are 20' away the "average" level would be closer to around 100dB.

So the peak specs are not "lying" but they are not telling you what you "expect".

This goes for any loudspeaker.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 12, 2016, 11:02:22 pm
In our 500 seat church, the 4 old QSC's would audibly compress at around 90db from the sound board, at the back(~90 feet) and turn to mush!
The two srx play cleanly past that, with dynamics to spare. Instruments remained seperated. For me, that's what I'm listening for, not 'how loud it will go', which seems to be what all the user reviews in the pro audio world talk about.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 13, 2016, 04:33:57 pm
Got it sounding really good today. Went around the room with REW. Noticed there is a huge tonal shift towards the lows in the stock setup. Sounded muffled and bass heavy. The Rew brought it back, but corrected to be a little too bright (like it was showing 6db down in the highs, when it really is around 3db correction.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Carneval on February 13, 2016, 07:17:24 pm

(http://uploads.tapatalk-cdn.com/20160209/e7fa06386be30186586ae62585352552.jpg)

You had some peaks and dips that seemed to change as you moved across the axis of the array. Were you able to correct that?

I also have to ask, did the engineering firm correct the rigging issues?
Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 13, 2016, 10:09:54 pm
That plot is a gated response from 1m with a single unit, with no dsp or room effects. The dips and peaks did still present themselves in the RTA throughout the room however. The 22band EQ on the dbx driverack took care of most of it. This was the end result:

(http://uploads.tapatalk-cdn.com/20160214/9e1f3476ff42fdbd97ae38e39e6f9624.jpg)
Title: Re: JBL SRX835p for FOH Mains review
Post by: Ivan Beaver on February 13, 2016, 11:13:39 pm
That plot is a gated response from 1m with a single unit, with no dsp or room effects. The dips and peaks did still present themselves in the RTA throughout the room however. The 22band EQ on the dbx driverack took care of most of it. This was the end result:

(http://uploads.tapatalk-cdn.com/20160214/9e1f3476ff42fdbd97ae38e39e6f9624.jpg)
You REALLY REALLY need to use a smaller scale.

Your vertical scale is over 250dB.  ANYTHING would look flat on that scale.

Maybe shrink it down to 30dB total vertical or something.

As it is-it is pretty worthless.  Sorry.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Carneval on February 13, 2016, 11:34:07 pm

You REALLY REALLY need to use a smaller scale.

Your vertical scale is over 250dB.  ANYTHING would look flat on that scale.

Maybe shrink it down to 30dB total vertical or something.

As it is-it is pretty worthless.  Sorry.

I noticed it was ruler flat and my first thought was smoothing but it looks like it's set to 1/12 octave. I didn't even think to check the scale.

Plus even with smoothing it should have SOME dips/peaks.

I also feel like it would have too much HF for my taste, being that flat to 20k.


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Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 14, 2016, 09:56:31 am
Realized the scale after I posted. Still though, after +-3 db ajustments, it was sounding alot better. You're right scott, I initially tried to get it flat out to 20k, but knew it wasn't going to sound good. The result was way too much HF.
There is a tab in REW for "House Curve" that would be interesting to learn more about.

But I think the purpose of the REW is to find WHERE the problem areas are, not how much compensation is needed, as that really has to be done by ear, while using the plots as a reference from my experience.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Ivan Beaver on February 14, 2016, 11:12:11 am
I noticed it was ruler flat and my first thought was smoothing but it looks like it's set to 1/12 octave. I didn't even think to check the scale.

Plus even with smoothing it should have SOME dips/peaks.

I also feel like it would have too much HF for my taste, being that flat to 20k.


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There is also no reason to go down to 2Hz and out to 30KHz.

That just makes the curve look a lot smoother than it really is.  But only if you pay attention to such things---
Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 15, 2016, 09:47:30 am
I forgot the set the range before exporting, I didnt work that way. I went to repost a better range, But didn't save the final plot.
Ivan, scott, please share some of your results with before/after EQ'ing.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Ivan Beaver on February 15, 2016, 12:35:57 pm
I forgot the set the range before exporting, I didnt work that way. I went to repost a better range, But didn't save the final plot.
Ivan, scott, please share some of your results with before/after EQ'ing.
I don't totally understand your question, but my opinion is that the loudspeaker system should be as flat as possible-within its capabilites.

Then any tonal adjustments need to be made on the console on a channel by channel basis.

NOT tuning the system so that it sounds "right" with a specific input.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 15, 2016, 02:39:35 pm
I'm not talking about theory, I'm asking what your experiences with RTA calibrations versus how they sound after. So 100% flat using RTA calibration is always the best? Or do you not listen to the final result?
Title: Re: JBL SRX835p for FOH Mains review
Post by: g'bye, Dick Rees on February 15, 2016, 03:05:59 pm
I'm not talking about theory, I'm asking what your experiences with RTA calibrations versus how they sound after. So 100% flat using RTA calibration is always the best? Or do you not listen to the final result?

Trevor...

I think you're missing the point that RTA is not the proper tool for system tuning, the chief drawback being it is "time blind".  You're asking people who use things like SMAART, EASE and SysTune to model and adjust systems to different rooms/environments how to use a simple, less effective tool to accomplish what it simply cannot.

Attempting to use RTA  in place of SMAART is somewhat akin to using an abacus in place of a computer.

BTW, what grade of chain is in that hang anyhow?  If you bought it at your local hardware store you should take the speakers down NOW.  Here's a link to your typical hardware store chain.  Note that although it is billed as "high test" and rated for a maximum load of almost two tons it is "Not intended for overhead lifting!"  The exclamation point is theirs.

http://www.menards.com/main/tools-hardware/material-handling/chains-accessories/5-16-high-test-chain/p-1444437045479-c-12174.htm?tid=-9075872613418166711
Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Carneval on February 15, 2016, 03:30:09 pm
I'm not talking about theory, I'm asking what your experiences with RTA calibrations versus how they sound after. So 100% flat using RTA calibration is always the best? Or do you not listen to the final result?

It depends what I'm tuning the system for. If it's a venue where a live human being skilled operator will be running the show, then tuning the system for flat makes sense. But if it's a nightclub, where a DJ is usually patching directly into the DSP, then I will tune the room for what sounds the best to me. This may not sound the best to everyone, but there's usually no one around to argue.

Here's a capture from SMAART on a nightclub I tuned last week. This is a pretty old club, it has 4x EV MTH1's and 4x MTL1 subs. This is the final measurement with all the speakers on, as it's the only trace that was left in the program when I opened it just now. The speakers and subs are spread throughout the room, so it's not very pretty through the crossover region. But the final curve has the subs about 10-15dB hotter than the mains, and the mains taper off by about 8dB or so. There are plenty of peaks and dips, but you would spend all day trying to correct that and you would probably end up creating more issues than you fix. I believe I used 4 or 5 bands of a parametric EQ.

Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 15, 2016, 04:19:26 pm
Thanks Scott. Glad my experience mirrors yours. I wasn't sure if it was either A: REW isn't setup properly, or B: don't expect a flat response.

My biggest thing is getting the response "somewhat" horizontal. As in, if I placed a ruler on top, how tilted is it?

Also, I find it interesting to compare the Gated Response to the in-room response. Does anyone use this method to determine actual room effects?

(Still trying to convince the key people in the church  we need to redo it, they think I'm overeacting, there are other players involved, making it difficult. Unfortunetly, I'm not in control, so you don't need to continue to convince me)
Title: Re: JBL SRX835p for FOH Mains review
Post by: Irvin Pribadi on February 15, 2016, 06:31:07 pm
Trevor,
In REW there is a function called waterfall graph.

This shows the time element of the FR sweep and gives a better picture of what's going on vs RTA alone which doesn't have the time element shown.
This will help identify trouble frequencies due to room modes and guide you in doing EQ work.

Another thing to read up is the equal loudness contour or Fletcher Munson curve. It helps explain why a stronger low end is more pleasant sounding thus going for a "ruler flat" room FR should not be the goal.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Ivan Beaver on February 15, 2016, 08:18:38 pm
I'm not talking about theory, I'm asking what your experiences with RTA calibrations versus how they sound after. So 100% flat using RTA calibration is always the best? Or do you not listen to the final result?
How does it sound using WHAT? an a source?

Live music? prerecorded? etc.

It is much easier to mix on a flat system.

But if you are not mixing-then it depends on the quality of the source  material and how/where it was recorded.

Different recording sound different-ESPECIALLY on the lower freq


Dick has already answered about using an RTA as being the wrong tool
Title: Re: JBL SRX835p for FOH Mains review
Post by: Ivan Beaver on February 15, 2016, 08:23:30 pm
How does it sound using WHAT? an a source?

Live music? prerecorded? etc.

It is much easier to mix on a flat system.

But if you are not mixing-then it depends on the quality of the source  material and how/where it was recorded.

Different recording sound different-ESPECIALLY on the lower freq


Dick has already answered about using an RTA as being the wrong tool
And just to add-how you eq a system for playback material will differ with  how loud you are listening to it.

As the level goes up-the preferred curve will change

With a live mix it is far easier to make the changes needed on a per channel basis.  With playback, the only tool you have is overall system eq

Yet another reason live is different than DJ
Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 17, 2016, 09:30:05 pm
Thank you very much Irvin.

Ivan, I'm using HQ prerecorded live material with no compression. Tracks I'm fimiliar with (blue rodeo live in massey hall, and Swell Season Live)
I understand how live verses prerecorded can differ, but if it sounds wrong, like shrill highs despite the software saying it's flat, on the recorded, then it usually presents itself on live as well.
I realize the term "RTA" might have been wrong, but my question still stands in regards to any room correction software and how it compares to "real life" listening.

I got the gohead to redo the hanging with:
-grade 80 1/4" chains
-2" washers on eye bolts through the bottom of the metal trusses so the load is vertical.
-grade 80 connecting links.

Anything else while I'm ordering hardware?
Title: Re: JBL SRX835p for FOH Mains review
Post by: Cailen Waddell on February 17, 2016, 10:38:52 pm
Grade 8 I think....   

The eye bolt washer and chain should all be us made.  The eye bolt should be a forged shouldered eye bolt.   No quick links.  Shackles that have been moused only.    Make sure you use grade 8 or grade 10 nuts and washers too. 


Sent from my iPhone using Tapatalk
Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Carneval on February 18, 2016, 09:05:14 am
Yes grade 8, not 80. But what you're really looking for is something that is rated for overhead lifting. Grade 8 does not necessarily mean this.

I would use aircraft cable instead of chain. It's going to be lighter and easier to work with, and probably cheaper. If you've never worked with it, and you're not comfortable fitting your own swages, go to a crane supply company and see if you can get it pre made to your desired length(s). I have a local company called Carolina Chain and Cable that is great for this. They can probably ship to you if you can't find anything local.

JBL has a very good white paper on rigging. I believe it's called something like 'Principles for Suspending Loudspeaker Arrays' or something like that. I'm on my phone or I would post a link.


Sent from my iPhone using Tapatalk
Title: Re: JBL SRX835p for FOH Mains review
Post by: Chrysander 'C.R.' Young on February 18, 2016, 10:47:08 am
The link you seek:

http://www.jblpro.com/pub/technote/tn_v1n14.pdf
Title: Re: JBL SRX835p for FOH Mains review
Post by: Trevor Crowe on February 18, 2016, 05:37:05 pm
Thank you for the links.
I ordered grade 80 1/4" dia chain, grade 80 connector links, and grd 8 fasteners.
The eye bolts were already U.S. Made, shouldered.
Everything is U.S. made.
Too late for cables.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Joel Mevis on August 22, 2016, 03:49:14 pm
Hi All,
I just wanted to share my experience with our new JBL SRX835p pair.

For reference, our church is a 500 seat auditorium with corner stage in a big square layout.

Our previous speakers were 4 QSC K12's spread across the bulkhead. The reason we switched was the QSC's struggled in the midrange clarity when pushed. They were great for low level, but that was it. We rarely go over 90db.

My theory was that a 3 way would provide better midrange clarity by having a dedicated driver for mostly vocals, while it frees the woofer to only have to go up to 500hz and the compression driver only has to do 2khz and up. Also, the drivers are working in their optimal bandwidth, so dispersion is very even at 60 deg.

By clustering 2 to cover 120 deg, the sound is very even across the room, and cuts off sharply near the walls.

The result so far is superior vocal clarity. Which is important for the sermon and worship music. A surprise bonus is amazing mid bass that the QSC's couldn't do. The JBL's have a nice hump around 60-120hz, where the dual 18" sub on the floor and take over the 40-80hz range. So the bass actually sounds like its coming from the mains which is nice.

I'm a little dissappointed by the highs, even after alot of EQ'ing. They don't seem to extend to the extreme top end. I was hoping for a little more 'delicacy' and detail in the highs, but maybe they just need some break in hours?

So the speakers can effortlessly project 100+db volumes for such a large auditorium. I'm very impressed. With the trade in on the 4 QSC's, the $2000 difference made a huge improvement.

I will post an update after our service tomorrow. (Mostly rock type worship)
(http://uploads.tapatalk-cdn.com/20160207/7870e43805def5c2eeb619a06a1cbb8e.jpg)(http://uploads.tapatalk-cdn.com/20160207/eb739562e089cd38353b56688b92796f.jpg)(http://uploads.tapatalk-cdn.com/20160207/d0252c14e8cb4c9b616a21dcc9a01fb8.jpg)

Trevor, did you find that by simply pushing the boxes together you got 120 degrees of coverage? Or did you space them out further? I am wondering if the boxes were designed this way?  We are seriously looking in to these for our church.
Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Holtzman on August 23, 2016, 06:32:35 pm
Trevor, did you find that by simply pushing the boxes together you got 120 degrees of coverage? Or did you space them out further? I am wondering if the boxes were designed this way?  We are seriously looking in to these for our church.

I might as well be the first,  that rigging looks to have multiple issues.  You might want to bring back in the guy who put up the batten bar.

Those more versed will be able to give you a detailed explanation but the chain is generally frowned on and requires inspection, the side load eye bolt.  Safety is job 1. 
Title: Re: JBL SRX835p for FOH Mains review
Post by: Ray Aberle on August 23, 2016, 07:58:30 pm
I might as well be the first,  that rigging looks to have multiple issues.  You might want to bring back in the guy who put up the batten bar.

Those more versed will be able to give you a detailed explanation but the chain is generally frowned on and requires inspection, the side load eye bolt.  Safety is job 1.
Scott, those photos are from the OP back in February. :)

Ray
Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Holtzman on August 23, 2016, 11:11:34 pm
Scott, those photos are from the OP back in February. :)

Ray

Ooops, sorry
Title: Re: JBL SRX835p for FOH Mains review
Post by: Ray Aberle on August 23, 2016, 11:27:11 pm
Ooops, sorry
Hehee no worries. We've had several zombie threads lately. Haha.

-r
Title: Re: JBL SRX835p for FOH Mains review
Post by: Scott Holtzman on August 24, 2016, 12:07:47 am
Hehee no worries. We've had several zombie threads lately. Haha.

-r

Speaking of zombie threads,  I am sure you saw the thread on humorous band names.  I always wanted to put together an all girl metal band called the zombie vaginas.  That one never got off the ground, or shall we say the gutter.

Ducking and running as usual.

Title: Re: JBL SRX835p for FOH Mains review
Post by: Vitalii Shalamov on March 30, 2021, 09:58:47 am
That dip you're seeing is probably a cancellation due to either a reflection (maybe off of the metal ceiling) or interference from the other box. You said you got a hole when you splayed them further than 30 degrees...could it have been cancellation causing a dip in HF instead? Are they splayed 30 total, or 30 per box?

RTA is really not the correct tool for this. You need a multi-channel measurement system so you can run a transfer function.

hello.
I have the same loudspeakers (jbl srx835). and I have very similar frequency response. dips: 300hz and 2500hz. peak 14000hz. did you get information about the origin of these dips?
thank you
Title: Re: JBL SRX835p for FOH Mains review
Post by: Vitalii Shalamov on March 30, 2021, 09:59:35 am
Here is the gated response I did at 1m using REW and MiniDSP Umic with cal file. As you can see the 3 way has a pretty narrow beam width compared to the more traditional 2 ways. (60 deg vs 90) So I believe the splay is correct. Any more, and there was an audible hole in the centre isle.
I've tried to bring up the dip at 2.5k and drop the peak at 12k. But that 12k peak could be the culprit. This week I intend to RTA and EQ around the room with my mic and laptop, and get it flatter. This is using the DBX 260, but I wondering if I would get better results with the new JBL iPad app for EQ, Just need to run a network cable up to the speakers.
Keep you posted.
(http://uploads.tapatalk-cdn.com/20160209/e7fa06386be30186586ae62585352552.jpg)
hello.
I have the same loudspeakers (jbl srx835). and I have very similar frequency response. dips: 300hz and 2500hz. peak 14000hz. did you get information about the origin of these dips?
thank you