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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Cameron M Gunn on July 27, 2019, 08:59:35 pm

Title: Looking to upgrade my subs
Post by: Cameron M Gunn on July 27, 2019, 08:59:35 pm
Hi all, I'm looking into upgrading my subwoofers and wanted to get some advice.

I stepped away from running sound for a few years and sold off most of my PA a while back. I've been getting back into it and have been getting by with the leftovers I had sitting in storage. Mainly doing shows of 150-250 with my gear and renting for anything larger. My subs are the weakest link in the system. I have 2 very old PAS Toc T2840b dual 18 subwoofers I got from a church that upgraded running off an I Tech 4000. I believe these are similar to Yamaha's SW218v. They work in terms of output for what I do, but only sound okay at best.

I normally run around 105dBC at FOH and 115-120dBC at the front row.

I'm looking at replacing them with the JBL SRX828sP. I have an opportunity to buy one new in box for $1300 from an install that fell through. I'd be starting out with 1 and adding a 2nd a few months down the road. Would 1 of the JBL's be able to get close in output to the 2 subs I have now? I don't mind taking a slight hit on output for a few months if it can get close. Right now I have nothing usable below 50Hz and if these are anything like my old SRX728s subs, that alone would be worth the switch.

Thanks!
Title: Re: Looking to upgrade my subs
Post by: Luke Geis on July 27, 2019, 11:28:53 pm
I think what you can hit those numbers. I feel that the box is truly capable of around 130db, so given the typical losses, you should be able to get right around those digits without working the sub too hard.
Title: Re: Looking to upgrade my subs
Post by: Roland Clarke on July 28, 2019, 05:57:12 am
Iíd second what Luke says.  The 828 is the best in its price range
Title: Re: Looking to upgrade my subs
Post by: Tim Weaver on July 28, 2019, 09:58:14 am
Yes.

The PAS Target series were not the greatest. A single passive 828 running from a bridged IT4000 would slay what you have now.

Also the powered 828 version would very much beat the PAS subs as well.


PAS had a "pro" series called the RS which was kinda OK for the time, but even then they were way down the list of what people wanted to use. They made some pretty decent Coaxial drivers and when put into a stage monitor they were pretty good. The mains were just so-so, and the subs were just not the greatest
Title: Re: Looking to upgrade my subs
Post by: Tim McCulloch on July 28, 2019, 12:09:23 pm
PAS had the right ideas about time but transducer technology of the era has nothing on today's big cone woofers.  Either JBL product mentioned will be significantly better in both output and LF extension.
Title: Re: Looking to upgrade my subs
Post by: Cameron M Gunn on July 29, 2019, 12:50:16 am
Thanks for the responses! Would there be a noticeable advantage in getting the passive version and using my I-Techs over the powered version? I do have a second I-Tech for when I add more subs. I'm able to get the powered version the same price as the passive version, so I'm considering going that route so I can leave the amp rack behind unless there's a good reason to stick with the passive/I Techs.

Yes.

The PAS Target series were not the greatest. A single passive 828 running from a bridged IT4000 would slay what you have now.

Also the powered 828 version would very much beat the PAS subs as well.


PAS had a "pro" series called the RS which was kinda OK for the time, but even then they were way down the list of what people wanted to use. They made some pretty decent Coaxial drivers and when put into a stage monitor they were pretty good. The mains were just so-so, and the subs were just not the greatest

I agree that the PAS subs aren't great. But they were free and served their purpose. One SRX being able to replace the 2 PAS subs is what I was hoping for. Normally I wouldn't hope to replace 2 lower end subs with a single higher end MI grade sub, but those PAS subs were pretty weak even 20 years ago when they were new. A clean 120dB from just 3ft away was a big ask for them...
Title: Re: Looking to upgrade my subs
Post by: Dave Garoutte on July 29, 2019, 01:18:56 am
Go for the powered.
Title: Re: Looking to upgrade my subs
Post by: Matt Graumann on July 29, 2019, 11:44:29 am
Throwing this out there (passive), these are NEW (even though the STX was discontinued a year or two ago), and they will sell them to you for $500 each, SHIPPED (I just got two more). 

Call them up and be nice...or, there is a listing by PSSL on FleaBay, too.  Make the offer, and buy them that way.   :D

I think they still have around 160+ in their warehouse.

JBL STX818s single 18" subwoofer  https://www.pssl.com/JBL-STX818S-18-Inch-Bass-Reflex-Subwoofer (https://www.pssl.com/JBL-STX818S-18-Inch-Bass-Reflex-Subwoofer)
Title: Re: Looking to upgrade my subs
Post by: Michael Storey on July 29, 2019, 01:20:14 pm
Thanks for the responses! Would there be a noticeable advantage in getting the passive version and using my I-Techs over the powered version? I do have a second I-Tech for when I add more subs. I'm able to get the powered version the same price as the passive version, so I'm considering going that route so I can leave the amp rack behind unless there's a good reason to stick with the passive/I Techs.

One thing to note (since you desire more LF extension) ...

According to the spec sheets, the passive SRX 828S has a much higher -3dB point than it's powered sibling. I find it odd as the cabinets and drivers are mostly identical, but I spoke to a JBL tech about it and he seemed confident that the numbers were correct. It would seem to imply an exuberant amount of EQ was implemented in the powered version to get down to 35Hz, which doesn't seem practical.

SRX 828SP (Powered): Frequency Response (- 3dB): 35Hz - 120Hz
SRX 828S (Passive): Frequency Response (- 3dB): 47Hz -120Hz
Title: Re: Looking to upgrade my subs
Post by: Chris Grimshaw on July 29, 2019, 01:33:26 pm
One thing to note (since you desire more LF extension) ...

According to the spec sheets, the passive SRX 828S has a much higher -3dB point than it's powered sibling. I find it odd as the cabinets and drivers are mostly identical, but I spoke to a JBL tech about it and he seemed confident that the numbers were correct. It would seem to imply an exuberant amount of EQ was implemented in the powered version to get down to 35Hz, which doesn't seem practical.

SRX 828SP (Powered): Frequency Response (- 3dB): 35Hz - 120Hz
SRX 828S (Passive): Frequency Response (- 3dB): 47Hz -120Hz

It's almost certainly the case that EQ is applied, and probably quite a lot of it, too. Not a huge problem so long as the limiters are set sensibly.
If you were to do a set of measurement sweeps at increasing levels, I'd expect the bottom end to show limiting while the 60Hz+ range keeps getting louder.

It's not how I like my systems to work, but that's where JBL's engineers have decided to compromise.

Chris
Title: Re: Looking to upgrade my subs
Post by: Luke Geis on July 29, 2019, 01:58:33 pm
I think the biggest reason for the difference is the Ohm's rating between the two options. The powered model is likely using a 2 ohm or lower speaker. This was a trick they employed years ago for the PRX line and the dual-element speakers. They design the amp to run at those low impedances hence getting good power to weight ratio out of them. The passive models use typical impedance drivers which may alter the characteristics to a more traditionally expected result.

The upside to the powered version is that ALL processing is done within it. Another plus that may improve the performance is that the length of wire between the amp and the speaker is only a foot or so long. This may improve the damping factor characteristics of the amp enough to improve its low-end reproduction ability? Perhaps they found a way to get a lower tuning and maintain output with low impedance, short speaker leads and clever EQ?

Where the passives tend to win out is that you can use an amp that will flog the shit out of the drivers with power and work the things to a very quantifiable performance standard. If you know you can push 6000 watts at the thing so you sling 4,800 at it, you know pretty much exactly what output you can acquire. Given the known sensitivity of the speaker, it is not hard to do. While the passive may not actually acquire more total SPL, at least what you are getting can be left unadulterated from processing. The lack of processing means a frequency response that may have humps that appear to have more output although it actually doesn't. It isn't that they don't perform well ( they do ) it is that you get a very predictable output.
Title: Re: Looking to upgrade my subs
Post by: Cameron M Gunn on August 01, 2019, 10:29:27 pm
I went ahead and ordered a JBL SRX828sP early this week. It came in this afternoon... And one of the magnets had busted off the driver in transit... So it looks like I'll be waiting for another week while that is sorted.
Title: Re: Looking to upgrade my subs
Post by: Luke Geis on August 02, 2019, 02:31:23 am
That sucks!!!! Definitely had to take a pretty good hit for that to happen. I had an instance once where I had ordered 4 Cerwin Vega coaxial monitors ( back story later ) and upon arrival 2 had been damaged during shipping to the degree that the magnets were literally knocking around in the boxes when then guy sat them down..... Of the other two that did work, one blew its HF driver safety fuse after only a few minutes of testing to see what the things could do. Needless to say, they were all back on a truck the next day......

So about those Cerwin Vega monitors. You have to keep in mind I have been doing this a while and this was back in a time when Cerwin Vega was still having good success and selling Pro Audio gear at Guitar Center and whatnot. I was privy to the fact that coaxial designs were better than conventional 2-ways and really wanted to get the jump on the technology before it was mainstream. At the time I didn't have Radian Microwedge money ( and this was just after the Microwedge was released ) so my options were little. There were only three companies that had coaxial designs that I could get a hold of, Cerwin Vega, FBT and P.A.S. I really wanted the FBT, but they had a very small presence in the USA and the P.A.S company was already on its way to closing and I wasn't going to afford gear that I knew would be unsupported, or hard to acquire support. Cerwin Vega for whatever reason was the only company in the USA with any kind of reputation ( be it good or bad ), had the support and had an affordable option. Needless to say, the venture was short-lived... After opening the things up to inspect the damage I got to see why they were so affordable. MDF, rat-fur covering, and stamped steel baskets with a magnet that was only glued on; poorly. After returning the speakers, I opted for a set of Renkus Heinz CFX-121M's which was the best, affordable and USA made speaker I could get. They still make and sell those same speakers today and the ones I have left are still kicking but and out on a show as I type this. In hindsight, a part of me wishes I invested in the FBT's. They eventually gained traction in the USA and have expanded that line fairly well. I think I did well either way though, as I am still making money with my old RH stuff and I have 8 RCF NX12SMA's also working away for me!

Don't be discouraged by your JBL purchase, The SRX line is still the best speaker for the money you can buy. You won't be dissapointed. Just turn the master volume all the way up to +12db and never look back. 
Title: Re: Looking to upgrade my subs
Post by: Cameron M Gunn on August 03, 2019, 03:16:44 am
Don't be discouraged by your JBL purchase, The SRX line is still the best speaker for the money you can buy. You won't be dissapointed. Just turn the master volume all the way up to +12db and never look back.
It definitely wasn't JBL's fault. I'm actually surprised the cab didn't show any visible damage considering it took a hit hard enough to break a driver. My dealer is sending a replacement and it should be in on Wednesday.

For laughs, I swapped out the OEM drivers in the PAS subs with some JBL 2258HPL drivers I had sitting in the garage this afternoon. Despite the enclosure and ports not being ideal, they still hit pretty hard and sounded noticeably better - just one of the subs was 6dB louder than both with the OEM drivers. Now I'm really looking forward to seeing how the SRX performs once it comes in.
Title: Re: Looking to upgrade my subs
Post by: Debbie Dunkley on August 03, 2019, 10:54:15 am
It definitely wasn't JBL's fault. I'm actually surprised the cab didn't show any visible damage considering it took a hit hard enough to break a driver. My dealer is sending a replacement and it should be in on Wednesday.

For laughs, I swapped out the OEM drivers in the PAS subs with some JBL 2258HPL drivers I had sitting in the garage this afternoon. Despite the enclosure and ports not being ideal, they still hit pretty hard and sounded noticeably better - just one of the subs was 6dB louder than both with the OEM drivers. Now I'm really looking forward to seeing how the SRX performs once it comes in.

I had 2 SRX828's arrive damaged/defective. The first was DOA but cosmetically perfect and the second worked but had cabinet damage. The third is the one I still own and has been FANTASTIC. It is worth the wait.
Title: Re: Looking to upgrade my subs
Post by: Rob Spence on August 20, 2019, 11:20:37 am
I think the bottom line here is the delivery people (usps, fedups, ups etc) are very rough on packages. Aside from very light weight stuff like usb memory, pretty much every package that is in a box arrives here with corners mashed, gashes in the sides or, like last week, a box of replacement batteries for an APC UPS arrived with all the tape seams burst and the cardboard ripped. The mess was just dumped in my package box.
Most people canít complain because the package was delivered while no one was home and the only recourse for a customer is to refuse delivery. The delivery companies wonít take your complaint as they say they are working for the shipper

Bah humbug