Limiter confusion
bsaller
Posts: 13
Hi All
My first time on the board! bear with me.
After reading \"start here\" and reading my DRPA manual I'm confused about the limiters in the DRPA. The manual says they are PeakStop limiters, but from what I've read on the forum, these limiters will not protect my speakers ( Not brickwall limiters). :roll:
Anybody care to give a rational explanation?
Thanks
My first time on the board! bear with me.
After reading \"start here\" and reading my DRPA manual I'm confused about the limiters in the DRPA. The manual says they are PeakStop limiters, but from what I've read on the forum, these limiters will not protect my speakers ( Not brickwall limiters). :roll:
Anybody care to give a rational explanation?
Thanks
0
Comments
Gadget
My dyslexia must be getting worse. I read PeakStop not Peak Plus!
Soooo my next question is: can I use a Symetrix 525 Comp/Limiter as a peak stop and should it be before or after the DRPA? Do I set the Threshold at +0db and the ratio at 20?
Thanks,
BTW Your avatar says it all!! 8)
If you must I'd place it AFTER the DRPA... and start @ +20 and slowly bring it down till it JUST starts to limit...If, of course, I was going to use it...at all
G
I do have my system gain structure set as per the info iin the \"Start Here\" section. My power to the speaker components are slightly under the \"Reccommended Max Power\" by about 100W per cab. The system sounds good with the DRPA since my amps and cabs are all in the DRPA. Setup is a snap.
I guess I'll keep the Symetrix Comp/Limiter for individual channel insert.
Thanks again for your help!
Beau
http://www.thebritishinvasion.us
You should be fine...
Good lookin bunch! Floyd RULES!~I enjoyed your songfiles!
Gadget
I'm the guy with the silver hair.
Those songs where recorde straight from the board. The soundtech at that club is the best I personnaly have ever worked with, but we can't get him to leave his club gig!
Know anyone in central PA with good ears. Doesn't need any equipment.
We have a JBL/Crown system and a large community system that none of us will carry!
We outsource our sound.
Anyway I took me JBL/Crown system and set it up today in my buddy's big garage. Tweaked some things and played with the limiters and re-did my gain structure. Also added 2 more JRX 118's and another 800wpc amp
Must admit it sounds pretty good and should handle 150-250 people.
Maybe I'll quit drumming and become a soundtech. Scary though!
Take care and you'll propably see me on here again,
Beau
Send me your email and I'll send you some of my song files...
G
tzone42@paulbunyan.net
trshot
http://www.breakingpoint.biz/
G
DRA
I did know this tamburine player...but that's for another forum :P
Kepp up the good work DRA & Gadget! I think I visit the RMF for some more DRPA and sound lessons!
Trshot
G
Then ya sit on the stage and wonder if the sound guy knows what he's doing, cause the last one only took 5 min. to do your drums and this guys taking 10 min. on the BD!
I must admit our keyboardist has me beat. His trailer is 14' and all keyboards and a couple amp stacks!
Hey Gadget, if you read this those songs where great and I'll email ya as soon as I get a chance!
My trailers are bigger.. my load is bigger AND heavier.. and my clout is ominous... 8)
G
Glad you liked them..
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As a newbie to this forum (and relative newbie to the DRPA), I had similar wants with respect to the compressor funtion (I'd like to have a Peak stop on the DRPA vs. a Peak plus - at least I think that's how this thread started).
Is there any value in using the \"LR\" compressor function set to inf:1 with a knee of 1 and threshold of 20db (and maybe a -db gain) to tame potential clipping on the input side of the DRPA (and corresponding output side)? My take is there isn't much value in this approach since the compressor function \"lives\" after the input stage but before the Xover stage in the DRPA.
The issue we're having is that my band uses a A&H WZ3 16:2 mixer which has headroom up to about 26-28db. Although I have set my gain structure according to the manual and tips that I've read on this board, the WZ3 will still clip the inputs of the DRPA if pushed much above 0db on the master faders. Most of the time our drummer runs the mix from stage and he's not terribly attentive to clipping the inputs while playing.
Also, many thanks to all the time you, Dra (and others) contributed in providing info on this board. The insight has been much appreciated as I've familiarized myself with the DRPA.
thanks,
Are you clipping (or at least close to clipping) the outputs? Or the amps?
Are you seeing the word \"Clip\" on the DRPA, or the compression led ingiting?
Regardless, lay out in detail the process you did to set your gain structure. Start with .... 1- pink noise to get board output meters barely into red. DRPA input meters at.....
DRA
I synched the gain stages of the board and the amps (QSC PL3402 for lows, QSC GX5 for highs) without the DRPA in the signal chain, so I'm pretty confident that I've got the sensitivity on the amps set correctly. (with the WZ3 output at 9db and no clips on the WZ3, the 3402 is will clip at approximately 22db, the GX5 is a little higher, around 26db if I remember correctly).
To synch the amps I used the pink noise file that was linked to from this site (20 min pink noise) - thanks for making this available. I set the pink noise input channel to fader to unity and set the trims so that the PFL level indicated around 6db. I then set the master faders so that the WZ3 would output about 9db (highest yellow light on the meter, with a very infrequent clip on the board (the red light might blink faintly once every 30 seconds or so). I then set the power amps one notch detent on the \"volume\" knob below the clip level (20db for the 3402, 24db for the GX5). With this setting, the amps would not clip as long as the WZ3 wasn't clipping.
The WZ3 level meters indicate clipping at 16db. The spec sheet for a WZ3 board indicates headroom of 26db at the outputs, and 23db of internal headroom. Generally, you can run the board well into the top of the yellow region of the meters (9db) without clipping the board. When the 9db meter is continually lit, some transient lows will clip the board (16db). At any rate, this board has a ton of headroom, more than any board I've ever used.
When I add the DRPA into the chain, a 9db level on the WZ3 (no clips on WZ3) will clip in the input stage of the DRPA (with transient peaks in source material). (It also would clip the lows on the output stage if the input levels stay above the clip point). And yes, the LCD display of the DRPA will blink \"clip\" in the upper left hand corner. The red light on the DRPA input meter blinks as well. I have the gain button on the back of the DRPA set at +4.
My concern is that when the WZ3 indicates output well into the 9db range, it will clip the input of the DRPA. Our drummer gets a little over zealous occasionally when tweaking the volumes, and I'm just trying to figure out a way within the DRPA to prevent clipping when the master faders get pushed a little to high. I was thinking that I could use the LR compressor as a limiter (inf:1 ratio) with a hard knee, but because of where the compressor sits in the signal chain within the DRPA, this won't help much on the input signal, but could help keep the output level from clipping.
My band normally plays at pretty reasonable (low) volumes (which is why a lot of bar & grill owners like booking us - patrons can carry on a coversation while we're playing and we don't chase the \"dinner crowd\" off), but we do occasionally get caught up in the groove and push the volumes up. I'm trying to figure out a safety valve for this reason. Right now, the safety valve is \"don't push the master faders above the shaded \"unity zone\" on the board or you'll clip the DRPA.\"
Any suggestions would be greatly appreciated. I guess maybe we should have gone with the 260 instead of the DRPA unit.
I guess that's one way to claim more headroom. But, when did -0- become = to +4?
Maybe running the channels at -4db (faux Unity on PFL) by reducing the channel gains. The problem is... the output meters reflect output. You may be able to max (travel) them out but you can still overdrive the DRPA inputs.
Sounds like self control is needed.
Gadget, got any ideas?
Some kind of pad between the board and the DRPA? :? :?
DRA
Beau - Won't Get Fooled Again file is out of phase...
Scooter...
Because the gain structure will work for ANY mixer-amp-processor combo we need to first understand that Pink noise has a crest factor which limits the dynamics of the process and renders it only semi usable...transient peaks from drums can easily exceed the crest factor of pink noise so some \"live\" music smarts need to be implemented here...For instance, My gain structure had the mixer master gains @ about +4 db over unity gain...with pink noise for a clip signal, when I run live my master faders RARELY get pushed to -30db BELOW unity for about 115db @ 10 meters! The board I have also has +28 db headroom, the DRPA has +22 however so your far better off having MORE than 12 db of headroom for transient peaks...Incidentally my output meters rarely ever hit -0- vu on the meters...for the aforementioned 115db
Remember, it's more important to set the input channels up so that unity gain and proper signal level are maintained on the input channels where the majority of the noise can be compounded in the system...Use of the PFL and master meters to properly set the input channels is critical...ESPECIALLY with dynamic sources like drums! (NO CLIPPING)
Perhaps a less \"amp sensitivity\" and more driverack for dummies approach here would be in order...instead of trying to hit amp sensitivity perhaps if you followed the setup in 'start here\"
http://www.dbxpro.com/forum/viewtopic.php?t=959
section. Where we are more interested in keeping unity gain in the entire system than trying to match amp sensitivity settings...
Otherwise, boost the gain of the xover sections to have the amps clip at a lower volume on the mixer and duct tape a max fader level on the master faders
BTW with my mixer peaks of +28 correspond nicely with the DRPA and I do NOT get peaks on the DRPA...
No the compressor won't help since its post input stage.. and well into the digital stage..but if you read this:
http://www.dbxpro.com/forum/viewtopic.php?t=1488
you can smooth the mix even further if you want...BUT beware... it only takes a little bit of action on the threshold to start into the gain reduction.. the meter may not even start flickering...
Gadget
In short, be less worried about specs and more interested in what you need to do to get the equipment to play nice together.
Thanks so much for the input, I'll try re-working the gain structure a bit and try to see the forest for the trees.
After my last post, I realized I neglected to differentiate between the pink noise and live music, but I figured you would catch on to the fact that much of the transient peak problem we have is with live inputs or using MP3s for testing (since pink noise does not have such peaks). We use e-drums to keep the ambient noise level down at the places we play, which produce quite a few transient peaks.
I've tried many of the pointers in the \"start here\" and DRPA user manual sections, but will give that another try. I figured it might be a bit more accurate to take the DRPA out of the chain to get clip points and such and then subsequently re-insert the DRPA into the chain. I can't really say that this has helped.
I'm curious Gadget how you don't get peaks in your DRPA with peaks of +28 coming off your board. If you're talking about not peaking the output levels of the DRPA, I can understand how to get there. But if you're saying that you don't get peaks on the input gain of the DRPA with a +28 signal, I'm very curious how you're acheiving that. Is there another peice of equipment between your board and your DRPA? Until I can figure that out, I think I'll go with the piece of duct tape across the faders at +5db. The sound we get from the DRPA (and peripherals) is excellenct, I'd just like to protect it from \"heat of the moment\" volume tweaks.
Just for reference, we (my band) generally play audiences of 200-250. We're over-40, weekend warrior musicians who play a different venue every night (most without house sound), thus, we need a very portable system (or more like, our backs need the portablity). We have a host of JBL, Peavey, and Mackie cabinets and various amps in our gear arsenal but usually play with (and I'm almost embarrased to write this), EV SB122s for the bottom end and EV ZX-1s for the tops with a JBL PRX518 powered sub. Outside of the sub and the amp rack, it's an easy system to haul around, sets up in about 15 minutes, and can carry any of the rooms we play (albeit getting pushed really hard at times). Since our volume varies from pretty soft to occasionlly really pushing the system, I'd like the system to be safe to run across the entire gain spectrum, so that we don't make any dumb mistakes that will require new speaker drivers. There are times that those little EVs get pushed pretty hard, particularly when our drummer's harmonica-playing neighbor sits in for a few blues tunes. In short, it's a pretty minimal setup, works well for the venues we play, and we don't have to haul trailers full of gear. It just needs a peice of duct tape at the +5 level on the mixer.