I have a stereo compressor/limiter/De-esser which I was given by a fellow musician with the words "What! You're not compressing the vocals??? Awh dude, you have to use compression on vocals!"

The reason I've never used it is because I have never really understood how they work or what they do, however I have been reading up up them over the last week and thought, right I will stick it in the rack and have a go.

The other point on them that I am still unsure about was whether to use it and insert to the channel or use it on the Left and Right Inserts and effect the entire mix.

Obviously using a compressor per channel gives more control but to compress every channel would requires 8 stereo compressors. Surely this is not the way other soundmen are operating.

Plus, on the compressor I have the connections are XLR in and out on the back. I was expecting to see jacks. XLR would lead me to believe that it was designed to work in the signal path i.e

Desk - Compressor - Graphic EQ - Amp.

I was reading the Soundcraft guide to mixing and it lead me to believe that anything used in the L&R Inserts produces the same overall result as just putting it in the signal path to the amps anyway!

My longwinded question is....is it better to compress one channel at a time or just compress the whole mix!

If I do one channel at a time I need a stereo jack to 2 XLR Y cabel. I don't think I have ever even seen one of those before!

Quote Scatamonkey:

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I have a stereo compressor/limiter/De-esser which I was given by a fellow musician with the words "What! You're not compressing the vocals??? Awh dude, you have to use compression on vocals!"

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No.

You CAN use compression on vocals, and it is one of the most common places to use it, but just because you can, doesn't mean you have to.

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The reason I've never used it is because I have never really understood how they work or what they do, however I have been reading up up them over the last week and thought, right I will stick it in the rack and have a go.

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This is a good reason not to use it, and also as you discovered a great reason to learn how to use it. A compressor used incorrectly can kill a mix exceedingly well.

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The other point on them that I am still unsure about was whether to use it and insert to the channel or use it on the Left and Right Inserts and effect the entire mix.

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Really depends on your situation. In your case it is most liekly to be most beneficial inserted into individual channels, but that is not a guaranteed.

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Obviously using a compressor per channel gives more control but to compress every channel would requires 8 stereo compressors. Surely this is not the way other soundmen are operating.

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Again depends. If I am running a full scale musical theater show, you better believe I have a compressor per channel. I may not use them, but I have them.

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Plus, on the compressor I have the connections are XLR in and out on the back. I was expecting to see jacks. XLR would lead me to believe that it was designed to work in the signal path i.e

Desk - Compressor - Graphic EQ - Amp.

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Bad assumption. Some desks have balanced insert points anyways, no reason you couldn't use it. XLR is just a more stable connection is all.

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I was reading the Soundcraft guide to mixing and it lead me to believe that anything used in the L&R Inserts produces the same overall result as just putting it in the signal path to the amps anyway!

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Similar but not quite identical. If it is inline instead of inserted, your fader position will control how hard you are driving the compressor. If it is inserted it will directly affect the level going to the amp(Or whatever is next in your signal chain).

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My longwinded question is....is it better to compress one channel at a time or just compress the whole mix!

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My short version of the answer is again, it depends on your specific situation. Given you don't seem to be compressing anything I suspect you will get the most benefit compressing individual channels if they are needed.

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If I do one channel at a time I need a stereo jack to 2 XLR Y cabel. I don't think I have ever even seen one of those before!

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Yes that is likely what you would need, however the jack is called TRS, not stereo. Specific reason is in this case it sounds like you have unbalanced insert points, and the cable is not carrying a stereo signal, but rather two distinct mono signals (And in opposite directions no less).

To give a few examples of how I have used compression on vocals...

Seperate Preamp/Compressor/Limiter/DeEsser/etc.
I run into the external pre first and then come into the console. This compresses the signal before it ever reaches the console and thus the compressed signal is sent everywhere.

Inserted Compressor per channel:
Pretty much what it says above. On most consoles this compresses the signal before it gets sent anywhere, so your monitors and effects get a compressed signal as well. Allows you to compress each channel differently to match the voice if needed.

Inserted Compressor on Group:
This compresses all signals in the group at once. This means if you have one person that starts singing much louder than your other vocals, that you other vocal volume can get pushed down by that one person. This could be a good thing in the case of vocalists that have very good control over themselves and balance their leads vs background singing well. It could be a bad thing when you aren't working with the above, as it means one person can cause your mix to shift dramatically with no notice.

This method also doesn't compress the send to the monitors. That means that hopefully you don't have as many issues due to feedback from the monitors, but it also means your vocalists isn't hearing necessarily what is happening in the FOH which could be bad depending on who you are dealing with.

But the reason I truly enjoy using this method is because when dealing with a strong singer with good control over their dynamics, this doesn't compress the signal going to the effects unit. And then when the singer gets nice and strong, my reverb kicks in to leave a nice tail after they finish, which in many cases is nothing short of ideal for reverb effects as when they are quite it gets so quiet as to be not noticeable, meaning I can clearly hear and understand what they are singing even quiet with little riding of the fader necessary to rebalance the dynamic shift.

Compress the Master Out:
You are compressing your full mix, so when your vocalist kicks in your instruments will get a bit quieter assuming your mix is anywhere close to decent. But this also means that an unbalanced mix can get made much worse much faster as well and is harder to control. But this won't compress the send to the monitors so a little better for feedback, but it will compress the effects as well as the vocals, and usually when your vocals aren't going your effects tend to be louder as a result.


Between these options I will typically compress either on the group or the channel(Or both), and have a separate compressor on the master outs maybe, but usually I just use that for a limiter for protection, not really to compress the overall mix, that is my job of riding the fader personally and if I am riding a dynamic build I don't want the compressor to get in the way.

Seablade

A compressor makes loud bits softer. If you make the loud bits softer and then turn up so that the loud bits are the same level as they were before, the soft bits will be louder.

If you only want this on one vocalist or one drum, then an insert on that channel is the way to go. And yes, you may want 8 compressors! (In real life you'll rarely have 8 compressors in your rack, which is where a digital desk with compressors and gates on every channel has major advantages.) You may specifically want to use it on multiple instruments/vocalists together, so use an aux output or an insert on a group. I do this a lot with vocals, bcos I feel that it holds lead and backing vocals together nicely.

Usually in live sound you wouldn't compress the whole mix. (Although see last month's SoS about big gigs where the big boys *do* use a compressor across the whole mix to meet noise regulations when they're working on stadium-sized gigs.)

Thanks Seablade and Grab - very informative answers. The compressor scares me a little cause I have heard that used incorrectly it can destroy the "Live" sound that a live band should have.

I like your suggestion Grab - I have 3 auxiliaries, 2 Pre and 1 Post. I could use the Post for all the vocal channels (1 Lead and 3 backing) together into one side of the compressor and back into a spare channel. And then just Insert into the Kick channel on the other!

I am mostly concerned about using it for the first time. How do you practice using it? I suppose I could hook it up and set it for NO compression to begin with and then ease it in?

As with anything in the production world, there is no hard rules. Vocals are normally the most "important" part of the mix, so are well worth keeping a little less dynamic... So a compressor on the lead vocal is nearly always essential for me. As well as keeping things dynamically in control, the attack and release settings can help sit everything a little better, controlling how things pop through the mix.

90% of the time I use the compressors as inserts, but sometimes use "parallel compression" by putting the compressor on a group, as well as routing the channels to the Mix. This means you can get extra volume, with a bit more punch, but doesn't affect the dynamic of the individual tracks as much. This kind of technique works great on string sections where Dynamics are important, but it can be hard to get enough volume too...

I also tend to group backing vocals together, and put a compressor on the group to help make sure no-one is especially loud etc...

A master compressor is also useful on the whole mix in bigger venues. This is simply down to the fact crowds like music up loud sometimes. And by compressing it, you don't have to batter peoples ears with random loud hits... it keeps it all glued together and less offensive

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I think I will test drive it on the lead vocal channel all by itself using the insert - can one of you give me some basic starting off settings. a 2:1 compression ratio seems to be the trend but the attack and release I'm a little unsure of.

I always used to tell my trainees: just because you have something in your rack it doesn't mean that you have to use it.

Personally my preference was to have compressors on vocals, but with the threshold set high enough that they only cut in if the singer did some serious yelling; bass guitar as you get some big level fluctuations there; and acoustic guitars, set up the same way as the vocals, just for that nasty bit where one string goes TWANG!

And, yes, I did have eight compressors in my rack (and eight gates too, but that's another story)

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Gear List: reverse only.

Quote Scatamonkey:

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I think I will test drive it on the lead vocal channel all by itself using the insert - can one of you give me some basic starting off settings. a 2:1 compression ratio seems to be the trend but the attack and release I'm a little unsure of.

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You may find this helpful:

Compressor quick set guide

but there's no substitute for trying the different settings - clearly not at a gig! - and listening to what they do.

Ideally you'd practise outside of the gig, but this may not always be possible. So if you've got time (and your bandmates will play along), practise a bit in the soundcheck. If you can't quite get the hang of it, turn it off for the gig. Rinse and repeat until you *do* have a handle on driving it.

My "default" setting on our vocal bus is about 2.8:1 and threshold set so that the lead vocalist takes about 3dB off when she belts. This slight bite on the compressor helps her voice, and then when all the backing vocals come in, the compressor takes a much bigger chunk off the signal. It's very much a case of using your ears though. As a quick guide:-

* If it's sounding harsh when they belt, you need the threshold down some more.
* If there's no significant change in level when they move around volume-wise in their normal range, you've got too low a threshold.
* If there's no significant change in level when they belt, you've got too much ratio.
* If it all sounds a bit meh, you've got the attack set too fast.
* If it sounds strange when they finish a note, you've got the release set too fast.

It's very easy to overdo compression. If you can definitely hear it working, you've probably overdone it - recordings these days are all compressed to death, so a live show's USP is that you get to hear what things actually sound like! You *can* get good results by taking large chunks off the signal (see above; I do the same trick with horn sections too, for the same reason), but you'd better be aware what you're doing and why.

Quote Dave Gate:

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And, yes, I did have eight compressors in my rack (and eight gates too, but that's another story)

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Nine gates including you!

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I cant remember a time when we ever had a proper sound check, if we're starting at 11 o clock in a bar gig I am there from 9.30 setting up and the band normally arrive @ 10.55, plug in and start playing - expecting it all to work and sound great from the word go.

I line check everything and play some music through but the luxury of an actual sound check is something I only dream about!

There are a couple of top notch soundmen in Derry, I think I will ask one of them to come to the next bar gig and walk me through the compressor on the fly!

I'm too nervous about using it for the first time in a gig without some expert guidance.

Quote Guy Johnson:

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Quote Dave Gate:

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<snip>
And, yes, I did have eight compressors in my rack (and eight gates too, but that's another story)

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Nine gates including you!

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I always left a few units empty at the bottom for crawl space during particularly cringeworthy gigs . . .

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Gear List: reverse only.

Quote Dave Gate:

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Quote Guy Johnson:

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Quote Dave Gate:

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<snip>
And, yes, I did have eight compressors in my rack (and eight gates too, but that's another story)

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Nine gates including you!

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I always left a few units empty at the bottom for crawl space during particularly cringeworthy gigs . . .

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Hmm I like this idea, I will have to start incorporating it into my compressor racks from now on!

Seablade

/me glances at his racks which have anywhere between 8 and 20+ compressors in the racks depending on which you talk about, need to find room for a crawlspace...

There's a good guide on audio compressors here:

How Compressors Work

...and there are a few good ones from SOS as well

eg. Compression Made Easy

Seablade has pretty much nailed it there, very informative.
On a basic level, I'd say the first port of call for the use of a compressor is when you've got a vocalist with a massive dynamic range, or more likely, bad to no mic technique at all. One of the first shows I ever did included a kid quietly talking, and then screaming in a fury at the top of his lungs. I was having to ride the fader massive amounts to maintain any kind of respectable balance. This inspired me to learn how to use them!