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Im running a show that I will do a little Kj/Dj and run sound for a BAND during the night. I have run sound one time in my life for a Band. I will be using 2 JBL PRX535's and 2 QSC 18 powered subs. My question is will my Mackie CFX 16 mixer be able to run sound for a band? I think they need 12 inputs but I also will be connecting 4 monitors. Thanks

Your mixer only has two pre-fader auxes, so that's only enough for two monitor mixes. Check with the band and see if they will accept that or not. If not, tell whoever is hiring you that you need to rent a mixer with more auxes to make the band happy and get some money for it.

IMO if the band is happy with two monitor mixes, they better be only 2 guys plus a drummer who doesn't sing, or else that band probably sucks anyway and will take any gig they can get regardless of the PA or pay situation.

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Jeff Wheeler, moonlight DJ/KJ

Thanks, Do you think I will have enough as far as sound? PRX is 650 each and QSC is 700 watts each. Thanks

Depending on the room size, you should be fine with that set-up - CFX16 has 12 XLR inputs & 2 stereo inputs (good for keys or effects returns).
Like said you will only be able to do 2 individual monitor mixes so find out which is most important to the members. Usually singer wants their vocals and some of the other instruments except drums & drummer wants - most likely kick, bass & a little guitar (from my experience). I have ran setups where the front 3 monitors were the same with mostly vocals & guitars & the drummer had their own mix.

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Thanks, the room is pretty large, its very long but I DJ there every Friday using 2 PRX 535's and 2 QSC Subs with one JBL Eon looped out and its pretty loud. Now the only thing is Im putting 2 PRX 525's with 2 PRX 535's (total 4 tops) and 2 QSC subs and 2 JBL PRX Subs (total 4 subs) hopefully this wont matter. I might even run 2 JBL EONS down the side of the bar to add more sound. The only thing I noticed is not a whole lotta of headroom on the CFX 16.

You might not be happy with all those overlapping top boxes. Before the gig I suggest you do a playback test with just the 535s on, and with both sets of speakers on. Walk around the room and listen in multiple places. Use whichever configuration you think sounds better.

With the subs, I would do the A/B listening test with a couple dance tracks and something with a prominent kick drum. Try all the subs clustered together, and the QSC subs on one side of the room with the JBLs on the other side. One way will sound better (I do not know which) and go with whichever way that is.


This is user error. Adjust the gain knobs, channel and master faders, gain trim on your EQ or processor, and on your speakers. Google about "gain structure." This recent post on djforums.com is worth reading as well: http://www.djforums.com/forums/showthre ... ost2279444

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Jeff Wheeler, moonlight DJ/KJ

You mention the room is large but not how large, your idea of large might not be the same as my idea of large so I can't be real specific. Generally speaking it isn't a good idea to mix different cabinets in your frontals, this often causes frequency cancelling because of the different wave forms the cabinets generate. This could be part of your "lack of headroom problem). If you do decide you have to use un-matching cabinets try to keep the matching cabinets on the same side of the stage. The 525's on one side and the 535''s on the other. As far as the "headroom" problem, this usually occurs from a lack of power, assuming your gain structure is in order. (this gets back to just how large of an area you are trying to cover, room lay out and how high the ceilings are). Another thing to keep in mind is the way it sounds empty is going to change dramatically once bodies are in the room. If you're having headroom problems with the room empty, it's just going to be compounded when the crowd arrives.

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Quickness of mind will deceive the eye

Thanks, If its going to cause problems using the 525 and 535's together I wont do it. I just thought it wouldnt be that big of a difference given one is a 3-way and the other is a 2-way but both JBL PRX. I felt there would be more to gain then lose by adding the additional speakers and would still produce good quality sound. But if the sound is going to suffer and be noticable I wont do it. Thanks

Not necessarily. I have been in situations where i've had to run different sets - brands and all - of speakers that have sounded fine together. Being these are all the PRX series there shouldn't be that much of a conflict. But as suggested is a good idea to do an A/B comparison with one set - then the other - then both together to see if there is any real sound loss.
The CFX as far as headroom is actually lower than other boards i've worked, but still can achieve very satisfactory sound once set correctly. Where do you have the faders set normally? You want them as close to unity as possible (different channels may need to be lower) then you have a little play upwards if needed - set the gain to where it's JUST blinking the zero level light then back it down a touch, or use the PFL and use the meter in conjunction with the zero level light, but on this board if you are close to zero level on that light, you are pretty close.
Use the master as the main volume control. I only say this because I have seen guys in the past that believe strongly that the master should be up at unity & the faders just up enough to start producing signal.

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I'm not sure why you would assume that just because they are from the same series that you would think there is less of a chance for conflicts. After reading the specs on the PRX525 and PRX535 I am even more convinced that they are far less than ideal to be paired up with each other. (especially clustered one each per side). The 525 has a 70X70 dispersion with a crossover @ 1.6k, the 535 has a dispersion of 90X50 and crosses over @ 430 and 2.6k and to complicate things even further it uses a horn loaded mid(probably to keep the mid in phase with the horn). This is not a recipe for success. I maintain that if you must use them together because you need the coverage and or power, you will stand a much better chance of a decent out come if you pair them together 525's on one side, 535's on the other. I am assuming you are running in mono.

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Quickness of mind will deceive the eye

Here's the issue with combining top speakers within the same coverage area, even ones of the same model. You can gain at most 6dB of output by doubling the speakers and power. However, cancellation is infinite. Different frequencies have different wavelengths, and at some wavelengths the drivers will be an appropriate distance apart to couple (and gain >0dB to 6dB) while at others they will cancel (and gain <0dB to -infinity.) This creates the harsh "comb filtering" sound you may be familiar with.

Try it in the room and see. If it doesn't sound better with the extra speakers, don't be surprised.

One better speaker will always give you better results than two lesser ones.

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Jeff Wheeler, moonlight DJ/KJ

Thanks, What if I run 2 535's and 4 Subs on stage and run one 525 down each wall about 40 feet?

You aren't going to hurt anything by trying it out. If it doesn't sound good with all the speakers, then you use 1 set - if it sounds good with both sets then you use both sets. Again I have used completely different sets of speakers simultaneously with great results - other times not.

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If you setup some delays toward the back of the room, don't forget to delay them. Most mid-range speaker processors will do 40 feet of delay, as will the inexpensive Behringer DCX2496.

Also remember that arrival times between the main PA and delay speakers will still differ as you walk around in the delay coverage area. It will differ a lot less if you delay them to the main PA though.

Do you know what your desired SPL is at the front and back of the room? If the furthest spot you care about is 80 feet from the main PA and your PRX535s are capable of 125dB SPL at 1 meter, then your sound field will look something like:
1 meter 125dB SPL
2 meters 119dB SPL
4 meters 113dB SPL
8 meters 107dB SPL
16 meters 101dB SPL
32 meters 95dB SPL

I would decide if the above is enough for you, and if so, use the 535s and worry less!

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Jeff Wheeler, moonlight DJ/KJ

Thanks Guys, This thing is really stressing me out but I think im just going to take your advice and try it with both sets if it doesnt sound right go with just the 525's and 4 subs. The place is rectangular about and im guessing 30w x 150'L . I usually dj in the back with 2 525's and 2 QSC subs with one EON out about 40 feet and I cover at least half the bar. If Im able to at least get good sound halfway down then that would be great. Thanks

ah, that shape sucks, because reflections off the walls reduce intelligibility as you get further from the PA. Delay speakers will help with that but you're looking at a balancing act between perceived directionality, which way the ear/brain thinks the sound is coming from (main PA/stage area, or delay speakers) and intelligibility. If you do delay speakers, like every other suggestion you have heard in this thread, adjust the delay time until it sounds the best to you. A slightly earlier arrival from the main PA will make the ear think the sound is coming from the stage even if the loudest sound is from the nearby delay speakers, but if you have too much mush from wall reflections, you are limited in what you can do.

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Jeff Wheeler, moonlight DJ/KJ