New (overwhelmed) user with Frankenstein PA

threeXseven

I am indeed new to this forum and new to the DR PA. This seems to be a board of extremely knowledgeable users with a lot of experience so it's the obvious place to start my intelligence gathering mission. I hope that someone will be willing to stick with me and offer some insight that I seem to be desperately lacking.

I better start at the beginning.

A little while back it was suggested to our band that we should get a Drive Rack PA + RTA mic to \"simplify\" and \"optimize\" our self described Frankenstein FOH setup. We were using a dbx X/O with a rack full of stuff running on the main inserts in order to get a better FOH sound and it sounded OK but definitely not up to the standard that we would prefer. From the description of the DR PA I thought we were getting something that really would solve all our problems quickly and easily. At this point I realize the great improvements this thing can give us but I didn't realize just how difficult it would be to set it all up. I've looked all throughout these message boards, read and re-read the manual and talked to friends who are more knowledgeable than I in this area and now I'm just completely overwhelmed by this thing. Any help/suggestions will be greatly appreciated.

Gear:

Mackie CFX 20 mixer with onboard fx (usually just delay on vocals or reverb on the main mix) and 9 band graphic EQ

DBX Driverack PA with RTA mic

QSC RMX 2450 poweramp

2 Behringer EP 2500 poweramps

2 home made passive 18\" subs (specs unknown, we had been powering these with the QSC and they never once acted like they couldn't handle all the watts we could throw at them)

2 Seismic Audio SAP 18S passive 18\" subs (frequency resp. 30Hz-500Khz, 500w, 8 ohm)

2 Mackie SWA 1501 15\" active subs (frequency resp. 36Hz-120Hz, 500w, hi pass X/O at 120Hz)

2 Mackie SR 1530 active 3 way full range tops (frequency resp. 38Hz-20Khz, 300w low, 100w mid, 100w hi, X/O specs unknown)

2 Peavey SP-2 TI passive 2 way full range tops still surviving from the '80's (frequency resp. unknown, X/O 800Hz, 300w, 8 ohm)

2 Peavey SP-2 G passive 2 way full range tops still surviving from the '80's, these were powered by daisy chain from the SP-2 TI's (frequency resp. unknown, X/O 1800Hz, 300w, 8 ohm)

We are a four piece rock band from Western Kansas with a growing understanding of the world of audio beyond a guitar and an amp and are greatly willing to learn. Right now we are recording so this is the best time to overhaul our setup and we don't have a clue what would be our ideal setup for what we have. Previously we sent the main outs from the board to the Mackie subs and looped full range out back to the crossover then to the power amps and passive speakers. At this point all I know is that we want to run from the main outs directly into the DR PA and be running our PA in stereo. I don't understand how to tweak the DR PA or what the ideal signal flow for our amps and speakers would be. As I said before I am completely overwhelmed at this point and I need someone to calm me down and get me on the right track.

Thanks in advance for any and all help and suggestions.

Paul
3X7

www.myspace.com/3x7music

kpippen

Hello Paul,

Welcome to the DBX Users Group Forum!... You know how Mondays are... Maybe I can offer you some assistance this evening...

Kevin

Dra

Getting all those different speakers to play together is going to be difficult at best. Something to consider... figure out which subs you like best and sell the rest, then take that money and buy more of what you kept. Do the same with the top cabs. Something else to consider... use the 15\" subs as low mids (more headroom for subs and tops amps).
Did you read the \"Read me first\" section? Tons-o-info there.

DRA

threeXseven

Thanks kpippen, I can't wait to hear your ideas.

Dra, I was kind of expecting a response of that sort and honestly that is what we would do if we could afford it. Another set of Mackie tops and a set of 18\" Mackie subs is on the list for '08. But right now we are saving up money to get our cd pressed and selling off our other stuff would barely get us started paying for more Mackie stuff.

Thanks for the quick responses guys.

Just so you guys understand a little better, the setup I described earlier is the setup we use when playing outside and we don't play many outside shows. For indoor shows we usually just bring the Mackies, the SP-2 G's and the 18\" Seismic Audio subs. Maybe that would be an easier place to start.

Gadget

What Dra was TRYING to tell you was that if you put speakers that have different coverage patterns, and different configurations together you will most likely end up with SONIC CHAOS! At the very least you will end up with comb filtering, nulls and modes that will ensure that much of the audience will be missing whole sections of the sonic spectrum...Some will get BLASTED with bass and some will get NONE AT ALL! Some will hear the vocals and some ...won't. It's an unfortunate fact of physics and we cannot shortcut it...The best you can hope to do is use the different speakers to cover different parts of the audience. The Peaveys could conceivably cover the middle and the Mackies, the outsides, but overlapping coverage is a SERIOUS no no. I am not the one to talk to about mackie, jbl or bose.. I think they are the most arrogant, useless, user unfriendly companies that think they are above criticism, and reproach...and their product quality has gone down the tubes as well...NOT good!

So let me get this strait... your running ALL THOSE SPEAKERS off three amps?(sans the mackie's of course) I guess we better start with what you do when you set up those speakers...

G

threeXseven

Wow, now I realize why we've always had people coming up to us between sets telling us we need to turn things up or down usually contradicting the things another person in a different part of the room told us needed turned up or down. Now I feel like an idiot. I always knew our FOH sound wasn't very good but now I see why.

So would I be correct in assuming that our biggest problem is in the mids and highs? We've never had any problems getting our low end to sound/feel good.

Most of the time our main set up consists of the Mackies, the 18\" Seismic Audio subs and the SP-2 G's (we compared the SP-2 G's and the TI's and decided the G's sound better). With that setup our stacks have the Mackie tops sitting on the 18's, the Mackie subs on the inside of the 18's and the SP-2 G's on speaker stands above the Mackie subs. The SP-2 G's get pointed so that they form a triangle on the far wall and cover the middle of the room while the Mackies get pointed straight ahead. Is this a good setup? Could we use those same speakers but set them up differently to get a better sound?

You'll have to forgive my ignorance on this subject as I'm just starting to get beyond the \"just plug this in here\" stage.

kpippen

Hi Paul,

Sorry,...but I've been extremely busy (it's a good thing) these past couple of days...:D

Anyways,...if you click here you can get a visual idea of what Dra and Gadget are talking about...and of what you have been experiencing... It takes a moment to load and the red dots may represent your speakers... You can add more and/or move them about (try putting two right next to each other...:shock:)... This should give you a visual understanding of sound wave propagation and mutiple source interference (aka..comb-filtering)... The black areas may represent dead spots...

One of the most knowlegable people in \"SR\" turned me on to this!...

Cheers,

Kevin

Gadget

You still haven't answered my question about amp power...I believe the only difference in the Peavey speakers is the older ones most likely have the aluminum diaphragms, you can verify this by removing a horn and looking at the cap on the driver. 22xt is the better titanium VC and the 22A is the aluminum one.

If you need wider coverage use the Peavey's and splay them so that the horns coverage patterns don't overlap this would require placing them as close together as possible and angling them outward...this configuration would NOT use the mackie tops. The correct way to get 90 degree coverage with 2 peaveys on each side would be to set one upside down on top of the other so the horns would couple... this configuration would also not use the mackie tops. Thus in this same line we could add an additional 90 degrees of coverage with the mackies, just make sure that they don't overlap coverage with the Peaveys. I would use the peavey's to cover the center and the mackies outsides because the peavey horns throw well. You could also use the mackie tops and not the peaveys. Using both to cover the same area would cause the sonic chaos I spoke of, and that you have experienced.

Next you need to read all the info provided in the \"Welcome read me first\" section at the top of the forum. Those posts will go a long way toward getting you started and up to speed on setup, tuning, and gain structure, as well as getting a flat preset. The New indoor method will help get the 2 different peavey's to play nice together (although about $70 should get you a pair of 22xt diaphrams...which I would definately do if I found the 22a's...

As for the subs... I might be tempted to put the 18's on one side and the Mackies on the other, make sure that the phase is correct on all subs so they are not working against each other...a 9 volt battery and a + to + and - to - should (on most every speaker except some JBL's) elicit an outward motion of the cone...If you stand between the subs and the bass disappears, one or the other is reverse polarity...whatever the configuration the crossover points need to be the same between the subs and the tops. Depending on the amp question you will need to go closer to 120 hz with the sub/tops crossover if you have insufficient power...


Good luck..

Gadget

threeXseven

Sorry I guess I don't know what info you're wanting on amp power. I'm starting to understand everything else though.

thanks Gadget,

Paul

kpippen

QSC RMX2450 and EP2500

Both channels driven:
500 watts 8-ohms
750 watts 4-ohms
1200 watts 2-ohms

Bridge-Mono:
1500 watts 8-ohms
2400 watts 4-ohms

Additional info for Dra:
Damping: >10000 @ 8-ohms
THD: 0.00001 @ full power 2-ohms
Distortion: <0.000002

Kev

Gadget

No no no.. you have 3 amps and 8 passive speakers correct? You list the RMX as powering the homemade 18's.. is that stereo? bridged? one of the EP2500's run the other seismics.. same question..., and one running the 4 Peaveys stereo I presume? I asked that question in my first post...

\"So let me get this strait... your running ALL THOSE SPEAKERS off three amps?(sans the mackie's of course) I guess we better start with what you do when you set up those speakers...\"


:roll:
G

threeXseven

Yes, they are all in stereo and all four Peavey cabs are run on one of the EP 2500's. Sorry I missed your inquiry.