RTA and Driverack

[heath_eld]

Was doing sound on a youth camp this week and had some hassles. Massive feedback problems, very echoey room combined with people who like it loud. Led to FOH feedback at a level I probably have never heard before. Also wasn

[Unalaska]

A driverack while is cool is it's own way but can be a real can of worms. For honesty I have 2 in different amp racks, configured to run any combination of mains in tri-amp or biamp modes (full range I don't use a DRPA generally). The DRPA's stay in the amp racks and are only really tweeked before they go out on a job. This keeps the number of returns needed on the snake down to a minimun and it's out of sight out of mind.

 

Some basics first though. Each Main out (LEFT/RIGHT) needs a 31 band eq as does each monitor mix. Cut not boost here. Mixer-eq-amp-speakers. That's it, no BBE, aphex, whatever. Even if you get a DRPA you still need the eq's. Yes its a few channels but it's a needed tool for the job.

 

I'd suggest the DRPA live in the amp rack. Since you want to use it witha speaker on stick app, you'll have to have it removed and placed post mixer somewhere in the room. If it were me I'd bypass the DRPA on SOS gigs and only use it for the passive stuff.

 

On the new DRPA+ the RTA can be run anytime vs the original (I have and not use the mic at all). It's pretty cool though and I can see where it would be nice to see the stuff going on. I don't know how much I trust it. The one experience I had with it I was only the monitor guy and I didn't trust the FOH to get it right.

 

Not sure on the PX being for powered boxes only. I'd say if you're not sure then get the DRPA, it isn't that much more.

[heath_eld]

What do you mean by a SOS gig?

 

So are you saying basically, i'd need a separate FOH EQ? Thats fine, i already have a DBX 231.

[Shaster]

SOS - Speakers On Sticks, as opposed to "pro" monster PA gigs - although the line blurs sometimes.

 

A Driverack is like a multitool, but it's not a magic box IMO. It's a combination of several pieces of gear that traditionally were "separates" - Graphic EQ, limiter, crossover, parametric EQ, analyzer...

 

Some people have had success using the RTA to tune their PA, I have not, and never use the function YMMV.

 

The DRPX is designated as a powered speaker unit because it only has high and low outputs. That is to say you don't need (or could you even use) separate EQ's, limiters, crossover points etc. for a powered box because it's all done for you (in the powered speaker itself). So you just need two sets of processing, one for your subs, and one for your tops.

 

BTW, IF you're running your passive boxes full range, you could use a DRPX, but you may or not regret the purchase down the road, if you wanted to bi-amp or tri-amp your boxes.

 

Have you downloaded a feedback trainer... so you can learn to identify errant frequencies? And if you haven't done so, I would also set your system up "at home" and iron out some of the bugs before gig time. Maybe you're way beyond all that, if so I apologize for giving you, "been there done that" advice.

 

Happy mixing!

[heath_eld]

WHere would i find a feedback trainer?

 

Good question about setting up the system at home. Certainly did to start with, but am constantly adding new parts that dont always get tried.

 

I do run my passive boxes full range. The MRX dont bi-amp, but i will probably one day move them to foldback duties and replace them with something biampable.

[jwlussow]

I used to use an external EQ when I ran the DRPA because it was a PITA to get to the EQ screen and make quick changes. Now that we use 260s we've dumped our EQs and use the PC interface to tweak the EQ. The 260 is a much more capable unit. I use the RTA "Wizard" but only as a starting point. I can only recall a couple of shows that the Wizard was right on without some minor tweaking. I still find the RTA very useful. Withe the 260, you can keep the RTA active and switch between input and output to see how the freqs are being adjusted. Very nice feature.

[agedhorse]

If you are having massive feedback with MRX-512's as mains, you must have something very wrong going on with your PA elsewhere. I have installed quite a few of these and I would have to say at that price point they are one of the easiest speakers to work with, and not feedback-prone at all.

 

What were you doing with the channel and main eq's?

 

Were you using monitors (foldback)?

 

Were you using compression?

 

Were you using effects?

 

What were you using for mics?

 

All of the above can have more impact on feedback than your main speakers IME.

[jwlussow]

My question is speaker location. Were the MRXs behind or right next to the performers?

[snoggin]

I have never really been able to use my RTA because the pink noise is too obnoxiously loud if there are any patrons in the room and there always are..

 

What do you do about that?

 

 

 

I used to use an external EQ when I ran the DRPA because it was a PITA to get to the EQ screen and make quick changes. Now that we use 260s we've dumped our EQs and use the PC interface to tweak the EQ. The 260 is a much more capable unit. I use the RTA "Wizard" but only as a starting point. I can only recall a couple of shows that the Wizard was right on without some minor tweaking. I still find the RTA very useful. Withe the 260, you can keep the RTA active and switch between input and output to see how the freqs are being adjusted. Very nice feature.

 

[Craig Vecchione]

 

I have never really been able to use my RTA because the pink noise is too obnoxiously loud if there are any patrons in the room and there always are.. What do you do about that?

 

 

I din't pink the room. You should baseline your system outdoors before you ever use it, and use that RTA info to set the basic EQ. Then you don't have to pink a venue room. Just use the baseline and make adjustments the old fashioned way...by ear...and not worry too much. The RTA in the Driveracks is not very sophisticated, and can't accurately account for time-based problems (build ups and cancellations), so its recommendatoins are just that..recommendations you should review before setting the EQ.

[jwlussow]

 

I have never really been able to use my RTA because the pink noise is too obnoxiously loud if there are any patrons in the room and there always are.. What do you do about that?

 

 

The first time we do a room we let the owner know what we need to do. We might do it the night before after closing or early enough that no one is in the bar.

 

We save presets for each venue so we only have to do it once and can recall the settings the next time we play there.

 

We NEVER run the pink noise when people are around. It is obnoxious.

[Unalaska]

I never have run the pink noise, I don't even own the mic. I would like to play with it a bit this week. A 1" HF diaphragm in one box is sounding weird, the other 3 seem ok but I need time and good weather to do this.

 

Question then: if I use the pink noise in the DRPA, will the signal be pre-Graphic/crossover/Delay/PEQ/Level? I don't need to blow horns doing this...

[jwlussow]

I believe it is post everything. You can hear the changes as the system adjusts the EQ.

[Craig Vecchione]

Yes, it's post-every. Has to be.

[heath_eld]

The MRX were right next to the performer but it had much more to do with the room. It was just "one of those" rooms, where you couldnt hear someone talking across the room for the echo. Where the sound was just "noise". You wouldnt get that in a room even vaguely designed for music, but it was just a dining hall at a camp site.

 

Its not a common problem with the MRX.

 

I use decent mics, Shure Beta 58s, SM58s and 57s, beta 52, etc.

 

We killed the monitors in the end to get it to sound reasonable.

 

I'm just curious about the DR because i think it had the potential (or at least, it claims to) be able to really measure the room well to help with this problem. I have a friend who says he used the Behringer equivalent to really help with feedback.

[Craig Vecchione]

You could use the FBK in the DRPA to kill feedback, but you'll also kill the tone. The RTA would absolutely freak in a glossy room like that...it would be a mess. As I wrote earlier, it doesn't handle time-based issues at all, and the brighter the room (the more reflective it is), the more likely you'll have extensive problems with cancellations and build-ups.

 

The best defense is exactly what you did...lowered volume by killing the monitors. The lower the overall level, the less sound will reverberate around the room, and more intelligible it will be.

[snoggin]

t^HANKS FOR THE RESPONSES

[heath_eld]

Thanks for the suggestions... seems like not too big a wrap for the DRPA.

 

Cheers

 

Heath

[jwlussow]

 

Thanks for the suggestions... seems like not too big a wrap for the DRPA. Cheers Heath

 

 

It's a good crossover/compressor/limiter/EQ/FBK. It's not a miracle worker. It is a single rackspace unit that replaces other single rackspace units. I wouldn't think of pulling our 260 from our rig but I also understand what it can and can't do.

 

The room you were in was untamable. A DR in your rig probably would not have helped at all in that situation.

[Craig Vecchione]

Exactly. There's no tool that can correct bad acoustics. Time-based anomalies are localized events; they appear in some areas of a room, but not everywhere. So your analysis at a single point (the RTA mic) can only generate a correction for that point. 5 feet away, there could be all hell breaking loose. You can take multiple measurements in the room, write the measurements manually, and then decide on some form of averaged setting.

 

Or just do the best you can by ear, and save yourself the trouble.

[Unalaska]

In reality it replaced a crossover. That's it. But it does mean the graph is flat to start and I have better control over what's happening.

[dennis a]

 

In reality it replaced a crossover. That's it.

 

 

With delay on each output, the ability to time align the components within your system make it much more than a crossover. Proper alignment can get you a lot closer to "flat" without touching your EQ(s).

 

Dennis

[Unalaska]

true, delay helps but that wasn't something in the rack I had already. I'm not running a hornloaded system either, the Rane SAC23B's were excellent and very simple to use. The AC23B's have a delay adjustment on some outputs though there was no "wizard" to help with that. I do use delay a little on the mid-ban outputs, not much though.

[agedhorse]

 

With delay on each output, the ability to time align the components within your system make it much more than a crossover. Proper alignment can get you a lot closer to "flat" without touching your EQ(s). Dennis

 

 

Assuming you have the tools and the understanding of what's REALLY going on to do the alignment correctly.

[dennis a]

 

Assuming you have the tools and the understanding of what's REALLY going on to do the alignment correctly.

 

 

Correct. The original question(s) was/were about what various DriveRack models are capable of. The fact that advanced tools and training are necessary to take advantage of these features is a topic for another thread.

 

Dennis