Multiple PX setup
Burstwurst
Posts: 10
I've just added three Driverack PXs to my PA system. I have stereo FOH using Mackie 1530z tops and Mackie SWA2801 subs. I run four monitor mixes into six Mackie Thump (TH15a) monitors. The monitor groups are split as follows : aux 1 - front of stage left (2 cabs), aux 2 - front of stage right (2 cabs), aux 3 - rear left (Kybd player) and aux 4 rear right (drummer). In this fashion, the front and rear monitors can be thought of as stereo pairs. Therefore, I've split a driverack across the front monitors and another across the rears.
Now, with any one of these systems (fr. mon, rear mon or FOH), I can get improved sound and level before feedback. However, my problem occurs when I bring up all systems together. I've set up each system using the wizard and all seems well until the other systems are introduced. It seems that one system induces feedback into another.
Are there recommended techniques when using multiple units together. For instance, it seems it might be helpful to run through the wizards for each unit with the other units off first. Then, bring up all systems and run the wizards again? Or, perhaps one should run the filter setup for each unit with all systems up and cranked to near feedback levels. With a single unit, I'm able to affect great improvement. But, once all systems are up, I'm seeing no more gain before feedback than with my prior graphic EQ system.
I'm sure that with a little guidance from folks who've wrestled with this same thing, I'll get on the right track. What are you fellows with multiple units having success with?
Thanks,
Bill
Now, with any one of these systems (fr. mon, rear mon or FOH), I can get improved sound and level before feedback. However, my problem occurs when I bring up all systems together. I've set up each system using the wizard and all seems well until the other systems are introduced. It seems that one system induces feedback into another.
Are there recommended techniques when using multiple units together. For instance, it seems it might be helpful to run through the wizards for each unit with the other units off first. Then, bring up all systems and run the wizards again? Or, perhaps one should run the filter setup for each unit with all systems up and cranked to near feedback levels. With a single unit, I'm able to affect great improvement. But, once all systems are up, I'm seeing no more gain before feedback than with my prior graphic EQ system.
I'm sure that with a little guidance from folks who've wrestled with this same thing, I'll get on the right track. What are you fellows with multiple units having success with?
Thanks,
Bill
0
Comments
What methods are you using for eq setup, crossover/filter setup (and what HPF for the monitors)
In other words, since you have PX, you obviously have the mics, so go through your Auto Eq setup for us...(be specific...)
In the mean time, have you read the gain structure/setup thread here?
viewtopic.php?f=61&t=959
Or read up on the pertinent threads on auto eq here in the FAQ section:
viewforum.php?f=60
Note that there are some threads on page 2 of the FAQ section that refer to Auto Eq.
There is so much to this that we suggest you read up before continuing.
Best regards
Gadget
I've read the supporting material and have great luck with any unit used alone. It's only when using multiple systems together I'm having trouble.
Mics : I use only Shure SM58s for vocals and have seven singers. 5 mics are evenly spaced across the front of the stage. Also, both the drummer (in the rear) sing as well. The drummer and B3 are grouped together in the center of the stage at the rear. They both have SM58s as well. I use SM58s or MD421s on guitar amps, one on each side of drummer. Bass is DI. Drums, Beta 52, SM57, MD421s and KM84s overhead. SM57s on the Leslie.
Monitors : I use 6 Tapco (Mackie) Thump TH15a powered monitors. These monitors have a 15" and horn and are self powered. These monitors have volume and EQ controls. I disable the EQ and prefer to keep the monitor gain controls at their center (detent - recallable) position if possible. Four monitors are across the front of the stage with the leftmost two monitors being fed by the driverack's (DR#2) left channel. The rightmost two monitors are fed by the same DR's right channel. The drummer and B3 player each have a single monitor. Their monitors are essentially back to back, facing up and towards the sides of the stage. These two rear monitors are fed by another driverack, left and right channels. Monitor system driveracks are fed by the mixer's aux sends 3 through 6.
FOH : Each side has a Mackie 1530z (1x15", 1x6" and a horn). These are self powered with their own non-adjustable x-over system. The 1530z has no controls at all. Additionally, each side has an SW2801 subwoofer (2x18"). I am using the full range input and leaving the gain control at the center detent, again for recallability. Another Driverack PX serves these. Full range outputs to L&R 1530s and L&R sub outs to subs.\ L&R.
DR#1 (FOH) : DR#1 feeds the left and right tops and subs as you'd expect. I set this up first and certainly hear a worthwhile improvement in sound. I'm pretty sure I have considerably more subwoofer than I need (this because I have a second pair of 1530zs, that are seldom used). The DR keeps them (the subs) under control much better than I had been doing. I placed the RTA mic in the center of the room as far back as the room allowed, about 20 feet from the front line and 20 feet from the rehearsal room's rear wall.
DR#2 (front monitors) : I've placed my RTA mic centered and as far away from the monitors as possible. This puts it between the drums and B3 at the center-rear of the stage, facing forward.
DR#3 (rear monitors) : With these two monitors on the floor and basically back to back, the only apparant logical location for the RTA mic seemed directly above them. This turns out to be the same place the RTA mic for the front monitors ended up. So, I used the same mic to set up both monitor systems.
I selected curve "C" for my FOH EQ and flat for my monitor mixes and ran wizards for all three systems, in order. FOH -> Fr Mon -> Rr Mon. I selected "music high" filters all around for the AFS. Each system now works great, separately, with AFS doing a good job and not butchering the sound. But, when I bring up all three systems, I begin to experience feedback that none of the Driveracks seems to be able to control.
I assumed that the driveracks were setting the x-over frequency and perhaps adjusting it during the auto eq setup. I've simply stepped through the wizards auto eq. I've been using 6 or 8 fixed filters on the "music high" filter setting. I'm using no High Pass filter with the monitors. After seeing the interaction between systems, I figured that there must be already established methods for using these things in multiples. I'll be re-reading the materials you suggested and look forward to your suggestions.
My thoughts at this point are that during setup, it's seems that I need to let all DR units hear and set filters on freqs that any of the three systems tends to feed back at. This would mean doing the "raising the gain to induce feedback" stage of the AFS setup for all three units simultaneously? Could this be helpful. Since my speakers are all powered, the PX seemed the best choice. Is there another (multi-channel) unit that sorts out these multiple chain issues?
Thanks
Bill
Would he benefit from reversing the phase on half (strategically) of the mixes?
Burst,
Do the "new" feedbacks tend to be high, mid, low, etc.?
It is possible that the room (stage) has reached IT'S max level and just can't take any more energy.
Are you using the PEQ's?
If not, you should be.
Are you lo-passing the the monitors at all? You should be. And more than you think. Either use the high shelf, or the filter on the low output for this.
Does that raise questions? It should.
DRA
Dennis
You may have read the material, but you are clearly missing the point...Placing the mic like that is a recipe for cancellations...lots of them. As is clearly stated in ALL the threads, indoor auto eq is difficult at best, frustrating, and technically not a good idea... especially with the PX, The DRPA+ is another story, but the methods still hold, one stack only...strait out from the speakers.. mic on the floor about 20' or so if possible on something soft like a towel...but better results are to be had with Dennis's ground plane measurement technique, or the outdoor method (for FOH). I also prefer to use flat and then do my own "to taste" rather than use the "curves" unless I set them up as a preset I can pick form for any given room, but that feedback problem could be in no small part because of the "C" curve in combination with the monitors and room buildup...
Again, not recommended...I find the best results placing the mic about where the singer would be in a correctly placed monitor for an SM58 mic, which is, monitor at the base of the mic stand, mic in the "erect" position...The max null spot for the sm58 is to aim the mic connector at the speaker...the measurement method that has yielded the best results for me is to place the mic like this:
1. set the HPF for the monitors @130-150hz HPF (eliminates a LOT of unwanted LF crap on stage...
2. sm58's aren't made for this type of application (monitors spread out all across the front), you should be using hyper cardioid mics that have their null points @ 3 and 9 oclock
3. set up a PEQ @160-180 hz with a @ of about 8-9
4. set up a PEQ @ 500hz with a Q of about 1
5. set up a PEQ @ 3k5 with a Q of about 2 or possibly a high shelf with a slope of 6db/ octave
these hold for the FOH as well (except for the HPF of course
the amount of cut (or boost in a few cases but NEVER the 500 hz one) will depend on the room, and the volume of the system.
LF should not be auto eqed indoors! Standing waves will render it inaccurate and usually very poor sounding (usually cut a LOT)
You might try placing the monitor speakers with the horns together (one set per side) like one big speaker and see if that helps.. if possible, maybe in a slight V formation with the woofers forming the top of the But the horns need to be as close together as possible. that way the horns couple and you don't get all that interacting horn pattern crap... which will be part of what is causing your problems...
Additional gain can be achieved by using your hand and placing it flat against the mic and cupped around the ball and increase the volume till it feeds and then .. if you can identify the offending frequency (the DRPA+ and 260 make it easy with the stand alone RTA function) and using the GEQ to cut those...
Also additional gain can be achieved by using the AFS.. but try using music medium as the filters will be wider.
AFS the monitors first and mains last with the monitors running at volume.
Use the PEq's I suggested (especially the 500 hz) to cut out room resonances , and in the case of the 3K5 for clarity purposes...
Try those things and report back
G
When you put the mic in the speakers nearfield what your actually doing is making the sound hitting the mic far louder than any reflection could possibly be.
The monitor technique also works well because the mic is in the position of the listener... and the mic that will be re-producing the sound. I generally start out with an Auto pass @ -o- flat high precision. I then take the mic and see how it sounds, and responds to my flat hand against it and cupped over it. I try and make it as loud as I think it will ever need to be (ya right...muso's are all DEAF!
If your referring to using the PEQ's to flatten the response, with the PX and DRPA you just don't have the number of filters available to do the job right, so, I have just been setting up those filters @ the points I specified, allowing the RTA to do it's job and then using the filters to mitigate the affect of the sound in the rooms.
G
Initial EQ setup :
FOH
Set up the RTA mic 4-6 feet in front of the top cabinet, aimed at the "center" of it's driver components. In my case (Mackie 1530z) this results in aiming at the midrange driver. This should be the only cabinet powered up. Flatten the GEQ. Run EQ setp (hold EQ button to start). Run RTA/pink. Review resulting GEQ curve (pressing next in the GEQ window lets you scan across the spectrum to see boost and cut amounts and locations in the spectrum. Now, apply PEQ that corrolates to the GEQ results. Then, flatten the GEQ and run RTA again. Your new GEQ results should be less extreme if you did any good with the PEQ. This will take several passes and will become tedious and fatiguing. Concentrate and expend PEQs first in the 170 - 700 range first as it's where the PX can do the most good. Document settings for this cabinet.
Sub EQ simply must be done by ear. Indoor results will not be helpful.
Monitors (EQ)
Set up RTA mic where the singer's mic would be, pointing directly at the "center" of it's driver components. Set up PEQs as we did for FOH tops. Also set high pass filters for monitors at 130-150 hz. Gadget has suggested freq centers for the PEQs that will improve monitor mixes are : 160-180hz / Q8-9, 500hz / Q1 and 3-5khz / Q2. I find doing this with PEQs at odds with using the PEQs to create a "flat system" PEQ preset. I'm thinking it's best to get the system flat using what PEQs I must before proceeding. I could use some clarification here.
Upon arriving at a new venue : (in this order)
Frontline monitors
If given the opportunity, set up RTA mic where the singer's mic would be, pointing directly at the "center" of it's driver components. Run RTA and review GEQ results. If there is a remaining PEQ, adjust for room response and re-run the RTA and again review GEQ results. Apply recommended EQ with remaining PEQs or with GEQ if out of PEQs. If the system is properly set up, is this venue "pinking" worthwhile?
Rear Monitors
Follow same procedure as for front monitors?
Front of house
Where the opportunity exists, Is it worthwhile to run the auto EQ with the the RTA mic perpindicluar to the floor and 1/8" away from it? If so, would the mic be out front on what would likely be a dance floor? Where?
AFS setup - use 6 fixed "music medium" filters all around.
Run the AFS setup on the front monitors first. Run AFS setup on the rear monitors next, with the front monitors at level. Finally, run AFS setup on FOH with all monitors at level.
I figured it'd be best to have a roadmap so I've typed this out. Gadget, please correct me where I may be wrong. You have my permission to simply edit my post if it needs corrections.
Ok, here's the deal... I just set up the monitors I use at the casino using Crown XTi amps and using them I had a hipass , a filter and 16 PEQ's ... and I used them ALL...
With only 3 PEQ's on the hi outs and 2 on the Low and mid outs (DRPA) and only 2 on the PX low outs I have found that I like to reserve the PEQ'a on those platforms for commonly re-occurring room issues. Midrange buildup is a biggie in my book especially in monitors. That's the reason for the 500 hz PEQ especially...Normally if I have the PEQ's I usually find something around 250hz as well as 500hz so when I don't have a lot of PEQ's to work I set up a broader one @ around 350 hz and try and cover both..with one PEQ.
The thing is, if you get that muddy thick sound happening it's usually a combination of the 160-180hz and the ones I spoke of before. It's going to be VERY obvious in the monitors.. especially the 250-500hz areas...
So, essentially why I use the PEQ's like that is for those typical area's where I find room interactions..
Now, as for the FOH Auto Eq, as I have stressed It's really not a useful "repeatable" tool...If you have a good "FLAT" preset and a you want to see what the room is doing to the sound, then compare them, but understand that if your putting the mic out in the room where multiple arrival times are going to happen you need to be aware of this and realize that room auto equalization is not a repeatable feature... unless you have the DRPA+ with it's new auto EQ algorithm.. and then only if you follow a pretty strict process of 20-25 feet out, on the floor on a towel or other soft non reflective surface, one speaker/ stack only.
If you want to leave the subs on you might as well turn them down a bit because the Driverack will do it for you...I usually just turn it down 3-6dB or so, then EQ by ear.
A PEQ is a pretty cool tool for finding problem frequencies, Simply set a cut of about 4-5 dB with a Q of about 5-6 and then sweep it up and down till you find something that is of interest, you can then narrow or expand the Q to affect more or less of the spectrum, and increase or decrease the dB to further fine tune the process.
Do I Auto Eq each venue, No. Do I recommend Auto Eq'ing each venue NO (way too painful a process on the ears). Once the system is set up and tuned properly very little equalization is usually necessary. Do I monitor the the system with the RTA? Sometimes, but it's usually when I sense a problem I'm having trouble identifying (this is not possible with the DRPA or PX only the DRPA+ and 260.
I have also found that the DRPA and PX won't let you get loud enough to really get the system tuned to LOUD live music.. it is a good thing because what it's doing is preventing the front end of the driverack from clipping...
1. I'll set the hi-pass filter at 45Hz. I'll also set the x-over point as low as possible, probably also at 45Hz.
2. Place cabinet on something to slightly elevate them and point into plowed cornfield.
3. Place RTA mic 20 feet in front of cabs.
4. Disable all EQ, both GEQ and PEQs.
5. Run Auto EQ
6. Set up PEQs attempting to emulate the GEQ curve the ayto-EQ created.
7. Flatten the GEQ and re-run the Auto-EQ
8. Re-adjust (fine tune) PEQs to further flatten resulting auto-EQ results
9. Repeat - ad nauseum
10. Save settings as 1530z flat W/O Sub
11. Adjust x-over to 120Hz and save as 1530z W/Sub
Once I've done the best I can with the three PEQs, does it make any sense to use the GEQ to target any remaining trouble spots, saving those as well into the preset? If I don't plan to use auto-eq at venues, might this be reasonable?
Also, if I plan to use my monitors with a 120-150Hz hi-pass, should I use this hi-pass while EQing the monitor systems?
Finally, while wrestling with the indoor techniques, I find I'll often see what appears to be a clearly recognizable curve in the auto-EQ curve, but, it'll have a single discontinuity (within that curve) with a wildly out of line freq. Should I expect much more predictable results outside, with fewer discontinuities doing this outdoors? Also, are you aware of any libraries of user settings for specific speakers? My 1530z speakers are quite common. Surely someone's already done what I'm about to do.
Thanks!
Good luck naming the presets so they are concise. I never have enough characters. Learn to abbreviate (a lot).
Do the monitor full range (hi-pass at their -3db point). That way when you need to use them full range you already have the data in a preset.
DRA
I'm starting to wonder if I may be better served if one of my three units weren't a PA+. I need to understand how it's RTA functions are more useful. Can the RTA function be used while the unit is otherwise processing? If the unit I used for FOH were a PA +, how might I benefit. Could the PA+ be used to assist in monitor setup, or to find trouble spots in all three systems? My sales guy is more than happy to let me trade up. I need to better understand the PA+ benefits over the PX.
Ok, both have the ability to do either powered, or passive speakers... the PA+ adds a mono sum capability for the subs, and mid outs...but the really useful things are:
A much faster and more user friendly Auto Eq algorithm that will almost without fail provide a better sounding setup
mute buttons on all outputs
Stand alone RTA
Why is the latter a big deal? because when you are trying to ring out the monitors it's a really nice deal to be able to see what frequencies are feeding back... As I said, with only a couple PEQ's to use per output isn't enough to do much good on most speakers...So I recommended you use them for room/tonal tweaks.
Once you have a good pass with the Auto Eq ... ok first off lets look at the Measurement mic...I assume that you have 3 of them now? here's the deal... cheap measurement mics have a couple of dark secrets...
1. They are LESS accurate in the LF and HF regions...
2. They are not consistent from one mic to another.. less duplicatable...
These inconsistencies make it imperative that you verify your findings and ring out the monitors. This process involves the flat and cupped hand technique...tweak and listen, rinse and repeat at higher volume till you get the desired results.
I have postulated many times that you can never get the monitors loud enough... because once you get the monitors up then the volume wars begin... that and listening fatigue set in...and the process starts all over again...
That said, using this very technique, the monitor in the picture achieved 121+ dB and I could literally take the mic and hold it 1 foot from the horn... aimed directly into it! Now, I don't want to sound like I'm bashing your speakers, BUT, the monitors I have there are VERY good to begin with... those plastic box things have some very difficult hurdles to overcome in the first place..that coupled with the fact that, as (even really great speakers) you get louder they change drastically in frequency response...
That, and the DRPA+ and PX don't let you get loud enough to really approach that level you are attempting to achieve...So you need to implement the ring out techniques...I just did this with the DRPA+ and a REALLY crappy set of Grund Audio 12" 2 ways... really light weight! (in more ways than weight :roll: ) I then transferred the setup to Crown XTi amps.. using only PEQ's ... but there were 16 of them...
It's always a struggle, but it can be done, I suggest you consider that the louder the stage volume is.. the louder you'll need to be @ FOH, and that ever escalating battle will be not be acceptable to many places we play in today...
Hope that answers your question...
G
Yes you can monitor the RTA display in real time, this means when you hit the [RTA] button the display will pop up... you can choose line or mic input.
yes you can induce feedback and the display will show where it is
Yes you pretty much need to be monitoring the display... it does have a slow decay however
Yes you can monitor the RTA display while mixing, or whatever...
yes you can use the results to set up the PX and then move it to FOH...
Yes you'll LOVE how fast the Auto EQ sequence is in the DRPA+
Yes you can probably call Northern sound and light and find that the DRPA+ is $390..and then if you bought your PX @ Guitar center get it price matched
No you can't induce a burst of pink noise from the DR but you could with the CD provided in the "Start here" thread... through the mixer...
I presume you have not read the "start Here" thread ?