# multi-channel (>2) compressors

#### jkowtko

##### Well-Known Member
We are discovering the benefits of vocal compression in a live band environment. We currently have a DBX 266xl ... works rather well but we are constantly patching the insert between vocal channels during the show and cannot pick up the ensemble as well as the leads.

For our analog sound system setup I would like to outfit the theater with 8 channels of compression in as little rack space as possible. With the DBXs we're looking at 4 rack spaces. I can live with this requirement if DBX is the best way to go. However there are at least a couple other options that I've found:

* The Presonus ACP88 looks like it has 8 channels in 2 rack spaces.

* The Behringer MDX4600 has 4 channels in 1 rack space.

Q: How does the Presonus compare in quality against DBX? Their price appears to be about 2x per channel on average.

Q: I don't expect the reviews on the Behringer unit will be very positive, but if anyone has had good experiences with these in live theater let me know. A friend two uses them locally said they work great for him (he has a two-channel unit). The MDX4600 is very inexpensive and price appears to be about 1/2x per channel compared to DBX.

DBX units are still fairly available used and I can pick them up for a modest price, but again I am interested in saving on rack space if I won't pay for it in sound quality.

Thanks. John

#### mbenonis

##### Wireless Guy
I'm a big fan of the ACP88, because it's quality is reasonable and it's size is right. It's probably not as good as the highest-end dbx compressor out there, but at the same time it's likely quite a bit better than the B-word compressor. We have two ACP88's in our theatre and they work well (although one has a bad channel).

#### avkid

##### Not a New User
Fight Leukemia
If you can I would try to find some used Drawmer.

#### SHARYNF

##### Well-Known Member
The Presonis is quite good, I agree the Drawmer is better it will take 4 rack U to get 8 channels.

Sharyn

#### jkowtko

##### Well-Known Member
For $250 a unit for 2 channels for the Drawmer vs$80 for the DBX 266XL, I think I would stick with the DBX if I was going to stay with 2 channels / rack unit. However if the difference in quality is that great, I will at some point in the future I may want to invest in one "good" unit for the theater to have on hand for lead vocals.

Mike or Sharyn, how would you say the Presonus compares to the DBX 266xl?

Right now using the DBX unit, I'm running at about 4x compression (to control the vocal peaks) with threshold of 0db, and it's averaging 3-4 LEDs of gain reduction (up to 10db?) during the vocal peaks. I can kind of hear where the threshold of the settings on the unit are on the verge of the compression being smooth vs. it being very noticable. I have noticed no popping, dips or cutouts, or distortion of any kind with the DBX unit. However we are running over PA with a loud band upstage, so you can't hear too much detail anyway. Is the Presonus going to sound noticably better in any of these areas?

I don't know exactly what separates good from cheap compressors (other than them physically breaking), so a little education/advice would be much appreciated here.

Thanks. John

#### mbenonis

##### Wireless Guy
I'll leave this one to to Sharyn. I'm not much of a studio person, and thus haven't really listened too closely to the compressors I use (to compare, at least). I just know that the Presonus works quite well.

#### SHARYNF

##### Well-Known Member
I guess it all comes down to the sound you are trying to get the Presonus is decent quality, but in a studio environment the drawmer just sounds better, tends to be less obvious. Once you get into the area of rack effects and processing etc, it really comes down to the sound you are looking for, it is sort of like different brushes an artist might select.

In general I try to be careful with using too much compression on live sound, what you wind up with is taking a live performance and starting to make it sound like a cd if you are not careful.

In my opinion, you are running the risk of adding and adding more and more effects and tweaking stuff when getting back to more basics would probably give you a better sound. Again personal preference, but what you can do in a studio, using stored automation etc is very different from what you tend to do in a live environment, Plus on your 01v96 you will have a fair amount of processing available on your inputs

From the earlier picture of your speaker layout things are still far from ideal. Since you are dealing with an odd layout, an other alternative is to use more smaller speakers, with proper alignment delay and better frequency response .

I like the Mackies, but tend to use them over time more for monitors, or some vocal reinforcement, but you need to recognize that they are still on the modest end of the spectrum.

Again everyone has their own perspective, but I tend to go with higher quality, simplicity, and try to use speaker placement, room treatment to fix the fundamental design problems with the venue especially if you are there for a long time. It is one thing when you are dealing with a new venue every few weeks, quite another when you are dealing with the same place.

Anyway all a matter of preference

Sharyn

#### mixmaster

##### Active Member
My dbx 1064s do well for me. It's 4 channels in one rack space with the usual controls for threshold, ratio, output (make-up) gain and a simple limiter. Two meters show the amount of gain reduction and either input or output levels. I have a pair of them in my drive rack so I have 8 channels of comp in 2 rack spaces. I don't think I would want to take them into the studio, but for taking the edge off the vocals in my live concerts they work fine. I have no idea what the prices were when they were purchased but I'm sure they were cheaper than Presonus. I'd definite take them over the Beringer units. I've used Beringer comps before and thought they left something to be desired. I didn't think they were very smooth and they didn't seem to have as much input headroom or output gain as I preferred. The dbx units I have can handle a hotter signal and seem to have more output gain. I've not used the Presonus units so I can't comment on them.

#### jkowtko

##### Well-Known Member
(I assume you mean the DBX 1046 ...)

I'm glad to hear you're happy with the DBX units, and yes I would mainly be using them for vocals -- either (as you said) taking the edge off, or boosting the lows a bit so they can be heard better in a theater that's got a bit of ambient noise (light dimmers weren't installed in the right place).

It's also good to hear what the audible difference would be with a Behringer unit. I can definitely understand headroom and smooth response issues -- after all, these units just have a VCA in them, so it's theoretically the same as you manually riding the faders, except that the unit should react faster than the human ears and eyes can, with less fatigue ...

I have listened to the board recordings with the DBX266xl inserted with 4x compression soft knee and auto attack/release, that was working constantly throughout our songs, and I find it very hard to detect any volume fluctuations as the singers reached their peak notes and phrases. (and these guys were belters -- could get very, very loud) No pumping or popping at all. So I'm happy with what 266xl was able to do.

I imagine for drums and guitars this is a whole different ballgame, and also where gating comes strongly into play, but for vocals I'm thinking the basic good quality compressors work pretty well, even without the frills.

Having a limiter on top of the compression might be nice, but I don't think I would use them both simultaneously. I could see putting a limiter on an output channel to set a ceiling on house volume, but not on an input vocal channel unless I'm trying to use it in conjunction with a lower compression ratio to emulate a larger knee (such as the 01v96, which has adjustable knees that can be set very large).

#### jkowtko

##### Well-Known Member
I guess it all comes down to the sound you are trying to get the Presonus is decent quality, but in a studio environment the drawmer just sounds better, tends to be less obvious. Once you get into the area of rack effects and processing etc, it really comes down to the sound you are looking for, it is sort of like different brushes an artist might select.
In general I try to be careful with using too much compression on live sound, what you wind up with is taking a live performance and starting to make it sound like a cd if you are not careful.
In my opinion, you are running the risk of adding and adding more and more effects and tweaking stuff when getting back to more basics would probably give you a better sound. Again personal preference, but what you can do in a studio, using stored automation etc is very different from what you tend to do in a live environment, Plus on your 01v96 you will have a fair amount of processing available on your inputs
Sharyn, yes I have the 01v96 now so I am going to try to use that whenever possible. But I wanted to have some extra channels around for analog board use.

I think the use of these extra analog units would primary be vocals ... if we ever do mic the band I'll pull in the digital board for sure so I have enough adjustment capability to figure out how to make it sound right.

Fyi, I did NOT get to mic the band for Smokey Joe's as I had originally hoped. The Music Director simply did not want to, and although the band sounded great (very talented musicians) they played at night club levels and there was really nothing I could do to help it. Extensive sound checks and volume settings proved somewhat futile as the adreline rushes during performances led to harder strumming. The keyboard player had a gas pedal that obviously overrode his amp settings. And the atmospheric changes affected the mid-bass resonance from night to night. All of which would have been pretty well controllable from a board ... but oh well, this is not a pro house and this is not my day job, so with the little time I had to work on this the only major thing I was able to accomplish without the MD's full cooperation was to figure out that compressors gave my vocalists a fighting chance !!

So, my use of compressors was primarily to pull the vocals up in volume at or slightly above band levels, but keep it limited under the pain threshold for the theater. There was only a small volume range I had to work with here ... and you could really tell the difference whenever the band paused and you could hear how loud the vocals were actually playing in the room, whereas with the band in full swing you could barely hear the vocalists at all.

And, after many complaints from patrons ("this show is too loud!") I basically rold told the artistic director that I'm not doing this again -- either get a different Music Director who doesn't have an ego, or I'll sit out on that production ... I am now a firm believer in micing the band for level and balance control (and yes, I don't need 8 mics on the drums ... 2 or 3 may be just fine -- I'll leave the attempt at Jersey Boys sound for some other day)

From the earlier picture of your speaker layout things are still far from ideal. Since you are dealing with an odd layout, an other alternative is to use more smaller speakers, with proper alignment delay and better frequency response .
I like the Mackies, but tend to use them over time more for monitors, or some vocal reinforcement, but you need to recognize that they are still on the modest end of the spectrum.
Again everyone has their own perspective, but I tend to go with higher quality, simplicity, and try to use speaker placement, room treatment to fix the fundamental design problems with the venue especially if you are there for a long time. It is one thing when you are dealing with a new venue every few weeks, quite another when you are dealing with the same place.
Anyway all a matter of preference
Sharyn
As for speaker placement, that's still a budget, time and effort issue. If these speakers were half the size and weight and had 2-way yokes on them, it would be relatively easy to adjust and reposition for each production. But they aren't, they don't, the theater has no money (or understanding) to work on this issue, and I don't have much time for each production to mount and fashing hanging brackets and to try to tweak their positions. I pulled down the two upstage "orchestra" speakers for the next show because the set's in the way, and I don't know where I'll put them up again for the next musical. I do know that where they were provided the most balanced sound I've ever had in that theater. What it sounds like though is that for the next step I should pick up a ref mic and do a little RTA around the theater to start understanding where the problems are, and invest in some insulation for sound dampening and bass traps.

But for speaker placement, take a look at our theater layout with the zero pit depth and highly raked seating area, and the need to have FX speakers in each corner of the theater. If you have any good suggestions on how to arrange 6 speakers to cover these needs I would love to hear your ideas.

#### howlingwolf487

##### Active Member
We have an ACP88 in our touring rig but our install rig has a Rane C4. The Rance is absolutely beautiful! Give one a listen and fiddle around with it sometime, if you can. The ACP88 hasn't been of any troulbe to my knowledge and I haven't noticed it too much during shows.

The OP could also try compressing subgroups for the ensemble as compared to individuals (if they haven't already).

#### herr_highbrau

##### Member
Dunno if you get this stuff over in the states, but Klark Teknik have their "Square 1" range. This is 3u, and 8 channels of either gateage or compression. I can't say the response to the graphic has been great but good things have been said about the dynamics!

If you want to go more expensive, KT also do a 4 in 1u compressor/de-esser. We've got em at work and I like them!

Have a look at this if you wish http://www.ktsquareone.com/

#### avkid

##### Not a New User
Fight Leukemia
Oh yeah we can get KT in the states.
It's a tad above the specified price range though.

#### herr_highbrau

##### Member
Always worth a double check, Square 1 has opened KT up to a lot of lower end venues over here! Just worth considering