Off topic - PLS HELP ME WITH MY COMPRESSOR!

[sepdrums]

I recently purchased a used Alesis 3630 compressor/limiter/gate to use on my PA system mix. I am having serious feedback problems and hope someone here that has PA experience can point me in the right direction...

I think it is limited to my compressor settings because when I bypass it, the feedback stops and the mix sounds 300% better...

1.) (dumb question BTW) - Does it matter what order on the efx. rack I put this thing - I.e. - before or after the equalizer?

2.) How the *(&Q#$ does one balance the compresor threshhold with the output? It seems that whenever I turn the output up, I get massive feedback UNLESS I turn up the gate threshhold to end the signal...that can't be right. But when the output is turned down, the volume level is way too low. Adjusting the outs on the mixer does the same thing that adjusting the output on the compressor does - big feedback.

3.) What is the difference between hard & soft knee compression...???

Sorry for so many questions. Unfortunately I got this thing used and with no manual.... If anyone can help I would very much appreciate it...

Thanks!
Erik

[This message has been edited by sepdrums (edited July 13, 2001).]

[studioVjeff]

You can Download the entire 19 page Manual here if you would like to have it... http://alesis.com/downloads/manuals/index.html

Jeff

[sepdrums]

Thanks!!!

Erik

[rus]

Originally posted by sepdrums:
I recently purchased a used Alesis 3630 compressor/limiter/gate to use on my PA system mix. I am having serious feedback problems and hope someone here that has PA experience can point me in the right direction...Thanks!
Erik

[This message has been edited by sepdrums (edited July 13, 2001).]

So, what religion is your compressor?

AH, HA, HA, HA, HA, HAAAAAAAAA!
man, I'm bored.

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\oo/_ gotta find a new face _\oo/

[ToBiMaN]

[Steveo the Devo]

Eric, I had a 3630 for years and although they are known mostly for their poor quality of compression, they can be useful.

ToBiMan hit the nail on the head when he said that compressors should generally be used as limiters when used over the total signal of a front of house mix, or foldback mix or whatever.
To use a compressor as a limiter it should be in 'hard knee' mode (although some like to set it in soft knee so the compression is less obvious), with the ratio set ~:1 (sorry, no 'infinity' key on my keyboard). You will want to run it with a very fast attack and a relatively quick release. The 3630 also should be set in 'peak' mode. The threshold should be set then at a point just below the level where your amplifier starts to clip (or where your speakers are being overdriven). When you use the compressor as a limiter it should be the last step in the chain before the amps. There are certainly other schools of thought out there as to some of this but that should see you out of trouble. With the compressor set up like this, the noise gate is an optional extra if you want to cut down on floor noise when there is no program signal.

The thing to do is play with it heaps, sort out what each thing does. Generally CD's arn't so good for this as they generally don't have the wide dynamics that you need to experiment with this stuff. Try it with someone talking, singing, screaming etc,

Your feedback thing is interesting. This can happen when a signal is highly compressed and then the output is booted up. By doing this, even the soft signals are made loud which will increase the likelyhood of feedback. As stated, it is best (generally) when compressing the whole of the signal like FoH that it be used as a limiter. This means that most of the time the compressor won't actually be compressing at all. Only on the very loudest of the vocal screams or snare hits - and even then only for a few milliseconds. The idea is to stop your speakers from selfdestructing.

Now when it comes to compressing a single signal (like a snare drum), that is a different story (and shall be told another day)....

[Drumsonly2002]

That's great info on compression. What would you recommend for compression just for drums? For example, you have a rack, with drum module, eq's, exciter, mixer, reverb, and a compressor, but this is only used for the drum monitor? Any tips appreciated, thanks.

[sepdrums]

TobiMan & Stevo & all....thanks a ton for the tips! I downloaded the manual and checked over the basics... On the back of the unit there are 2 switches for +4 & -10 on each channel...I had one at +4 and one at -10 so it was the first part of my problem... I have messed with the dials at the expense of the rest of the band's hearing. Some of the feedback I was experiencing was definitely related to compressor settings.
Stevo - I have heard that the Alesis is not as good as the dbx unit.... I will investigate that as well...

When I add a Sonic Maximizer to the chain, I assume it needs to be before the compressor...??

I am farting around with it and learning more each time... hopefully I will have it down for our gig in a few weeks. For now, our recordings are sounding much better without the compressor than with.

One thing I am learning is how sound settings can really wreck a decent band, & vice versa

Erik


[This message has been edited by sepdrums (edited July 16, 2001).]

[kv968]

Erik
Since the maximizer enhances the highs and lows, and the compressor sets limits for them the logical place to put it is before the compressor. I don't have either and don't really know (and I'm sure I'll hear it if I'm wrong) but that seems right to me.

Post back with your Alesis/DBX comparison too. I'm sure I'll be buying one soon and every bit of info helps. Post which DBX model you check out also.
Kevin

[Steveo the Devo]

Hi Drumsonly,

I'm not exactly sure what you mean. If you are referring to placing a compressor over the whole of your drum fill/monitor then I would recommend using it as a limiter (described above). When it comes to compressing my drums I generally use a separate compressor for each track I want compressed.
That is, if I want to compress my snare I use a compressor dedicated to compressing my snare. I then use a different compressor to compress my kick drum. The key to this is again to play around with it. Different compressor settings can give anything from a weird 'pumping' or 'breathing' effect (which is not good) to a tight killer sounding snare or kick sound. You would be suprised how a lot of the awesome drum sounds you hear are the result of compression. I have on occasion compressed the 'whole' of the drum kit (by inserting a compressor over the drums subgroup on the mixing desk). I did this to keep the drums 'punchy' but the result is not as good as the separate approach (all depends how many compressors you have!).

The compressors in the TD-10 (not expanded) are all but useless. I have been told that they work a lot better with the TDW-1. My preference however is for 'outboard' compression and effects. I know that this is an expensive way of doing it but I'm a bit too perfectionist to put up with the factory FX on the TD-10 (I know I will get flamed for this ).

IMHO, there is no comparison between Alesis and dbx. Dbx wins hands down. Compression is also something that is hard to compare unless you have been using compressors for a while. It is best to learn all you can with what you have got and develop an ear for it first.

Eric, you said you are using the compression to record your band? What are you trying to achieve by using the compressor? If you are trying to add 'punch' try - Threshold - midrange (between -10 and 0db); Ratio lower midrange (about 2:1); Attack low mid (between 5 and 50ms); Release low mid (150 - 500ms); Output high mid (say about +10db). This will of course depend on the style of music you are playing (and more importantly the output level of your mixer), but you should be able to get a decent result by slightly adjusting these settings.

One thing is certain - any piece of equipment you add to the signal chain has the potenetial to ruin the sound. When all else fails just bypass it. Better to have a decent sound that a rack full of colourful lights!

[Cyberjam]

A little OT.

Anyone try the Behringer MDX2200 compressor yet?

I have the opportunity to buy one for a decent price. I am looking to compress both my drums (TD-10 unexpanded compressor does not work very well, but what do I know?) and my vocals (need all the help I can get).

I will be making the purchase real soon. Any help on the subject of compression would be greatly appreciated.

TIA

[szvook]

If you have some $ to spend, I would recommend - http://www.focusrite.com/products/platinum/p3.html

I love what my Compounder does to my kick and snare.

This would be your only purchase that you would need to get the best, unless you want to try - http://www.drawmer.com/dl251.htm

Those are the cream of the crop.


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szvook

[This message has been edited by szvook (edited July 18, 2001).]

[This message has been edited by szvook (edited July 18, 2001).]