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  • JBL VRX & PRX Series speakers and subs

    Hello!

    I'll be getting a new installed PA system for a smaller venue soon. The venue is about 100 people max, and the system is usually run at lower volumes of about 90dB at the FOH desk.

    There is currently a QSC GX5 that will be used with the new system, everything else will be new. The goal is to fly the speakers and sub(s), so that limits my options. For this reason I was looking at the JBL VRX and PRX series, specifically 2x PRX412M speakers running on the QSC GX5 amp, and 1x VRX915S or VRX918S sub running on another amp. The original plan was to bridge a Crown XLi 2500 amp for a single sub, which will fly in the center between the two speakers. I figure two subs aren't needed for the smaller room, and after doing some research on sub positioning it seems that the best location for subs is probably flying in the center to avoid dead spots and cancellation issues. I'm thinking the VRX918S may be overkill for our situation, and if I could save some money and not hang 80lbs worth of sub woofer by getting the VRX915S I'm all for it.

    Just looking for some feedback on this setup. We currently use a pair of 700W (program) EV Eliminator i speakers on poles with the GX5 amp and run the dials around 9 o'clock with plenty of volume for us. So we don't need massive volume, but want good and clear sound. I was looking at this setup because it fits our budget, and the speakers and subs have flying mounts. It also seems these have superior drivers to the SRX or other cheaper JBL series.

  • #2
    I was just looking at the specs for both subs and while I'm not a gotta have 18"s guy, the additional performance of the 18" in this case is easily worth the few extra bucks. (Especially since you're planning on only running one.)

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    • #3
      First thing I would suggest is to get a pro involved, not that knows the math. For a typical application where ~90dB SPL is needed, the GX5 alone with those speakers would be plenty. Use the internal crossover and assuming you are ok with mono (in a small room usually mono works out better anyway) you are good to go. I would also suggests the 18" version. The 2500 amp bridged is WAY more power than you need or than I would recommend for the sub. But, since you are looking at new gear, I would strongly recommend going with the powered vrx or PRX as the onboard processing is well executed and in general it's a better solution in every regard.

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      • #4
        Is there no stage... or another compelling reason that you couldn't center-cluster a pair of subs (or just a single sub) on the ground under the front of a stage? Getting 90dB at the back of a small room shouldn't be much of a challenge. I'm certainly no fan of the VRX line array tops... maybe if they'd offered a 10" woofer model, I dunno. Where are you located?
        Where the Mississippi River runs west...

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        • #5
          For a small room, I don't see any problem with (properly deployed) VRX.

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          • #6
            Just a reminder. Getting 90 dBSPL to the back doesn't speak at all to the quality of the sound, only to the sound pressure level. I would also recommend using the self powered versions if possible. Unless you posses the equipment and skills to dial it it you will get much better sound quality using the self powered versions. It is also likely they will be much more reliable and easier to install.
            Don Boomer

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            • #7
              Originally posted by WynnD View Post
              I was just looking at the specs for both subs and while I'm not a gotta have 18"s guy, the additional performance of the 18" in this case is easily worth the few extra bucks. (Especially since you're planning on only running one.)
              The speaker itself is only a few more bucks, but running at 4ohms you'd need to put a chunk of change more into a bigger amp.

              I've gone with unpowered speakers because they seem the easiest to connect and flip the whole rack of gear on with a single switch, for our setup anyway. We also run them 50-100hrs a week and would prefer to replace an amp rather than a full powered speaker.

              I'll add that we have a Driverack PA+ as a crossover and we use it for room EQ, and if necessary a 31-band GEQ on the mixer.

              What amp would you get to pair with the 918S or 915S? I was thinking the 1500W in bridged mode would come close to the 1600W program rating of the 915S, so if needed we can push it harder to keep up with 2 speakers and 1 sub. The 915S can produce 126dB SPL, and the 918S at 130dB. Do you still think there's a need to get the 18"?

              And yes, there is no stage and one cannot be built.
              Last edited by spargo; 08-06-2014, 08:14 PM.

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              • #8
                You didn't look at the 1 watt specs. The 18" is 4 db louder. That counts as much as a doubling of power for free! Yes the 18" will handle more power. Yes it's 4 ohm, but on most amps that immediately a higher power output than if it was 8 ohms. I don't see a down side to spending the few extra bucks for the 18".

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                • #9
                  Originally posted by WynnD View Post
                  You didn't look at the 1 watt specs. The 18" is 4 db louder. That counts as much as a doubling of power for free! Yes the 18" will handle more power. Yes it's 4 ohm, but on most amps that immediately a higher power output than if it was 8 ohms. I don't see a down side to spending the few extra bucks for the 18".
                  Woops, yes you are correct. However, the 918S is 8ohm and the 915S is 4ohm. So I'd need roughly 1600W @ 8ohms for the 918S.

                  Now, for an amp...normally I am violently opposed to Behringer gear, but I've been reading some surprisingly good reviews on the iNuke NU3000 amp. It's only $230 and will output 1500W bridged. Tests show the actual output is closer to 1100W at 8ohms, but seems hard to beat for the price. Any thoughts on that? Especially since we will run these amps a lot, replacing a $230 amp down the road sounds appealing.

                  Comment


                  • #10
                    You know what sounds even more appealing than replacing a $230 dollar amp? Spending your money one time and getting something you're less likely to need to replace. Chasing after the most-watts-for-least-amount-of-money is a fool's errand more often than not.

                    I'd suggest what others have: go with the powered versions and then spend less time worrying about what you'll need to replace down the road.



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                    • #11
                      Originally posted by guido61 View Post
                      You know what sounds even more appealing than replacing a $230 dollar amp? Spending your money one time and getting something you're less likely to need to replace. Chasing after the most-watts-for-least-amount-of-money is a fool's errand more often than not.

                      I'd suggest what others have: go with the powered versions and then spend less time worrying about what you'll need to replace down the road.
                      So you're talking a VRX918SP, and 2x PRX712?

                      My question is how to go about running long power cables along the ceiling and down to a power source. And does the VRX918SP have a powercon connector? I assume you need to find some long 3 prong to powercon cable?

                      Comment


                      • #12
                        Remember my comment about finding a professional to help you develop and understand a proper solution? Your comments about how to run and switch power further reinforce my suggestion. No self respecting professional would consider handing power for a powered speaker in the manner you suggest. It would also be helpful for you to understand the math behind power and spl calculations, you have plenty of sub spl and too much power (or power you won't be able to use). The point of diminishing returns before power compression becomes a major issue as just a little over the continuous power rating of the speaker. I rarely recommend more then 1.5x the continuous rating because I understand how many manufacturers rate their speakers. We have discussed this on the forum before and there is a lot of good info a search can return.

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                        • #13
                          Back up a sec, prx412 with a vrx918? A 400 series mid/high with the 900 series sub? Seems a bit unbalanced right? Here is where using a powered speaker can really help, and you can still use the gx5 on monitors. The drpa can used or not depending on what you're looking for. If you must go passive at least get something better than bottom of the barrel jbl.
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                          • #14
                            Don is clearly correct in that powered speakers are the way to go here. OP, you simply don't know enough about how these systems work to set it up reliably. It can of course be learned, but if results are needed in a short span of time, you'll be wise to let the pros who design systems do that homework for you...that work is built into powered speakers.
                            .....

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                            • #15
                              With the small size and reasonable volumes, why not just fly 2 JBL PRX735 boxes and call it a day? In addition to saving you a bundle, the sound will be articulate with no need to balance out tops and subs. At +/- 3 dB down to about 40 hz, there should be plenty of low end, and it will likely look better versus flying subs in a small venue. So, easy, cost effective, quality sound, and good aesthetics.
                              www.nextexitrocks.com

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