dvidos Posted April 21, 2008 Share Posted April 21, 2008 Hello, please excuse my ignorance, but do compressors work with mic level signal as well ? I am asking this because our audio mixer does not have insert points. So I thought of plugging each mic into a compressor channel and from there take each output signal to a mic channel of the mixer. I am thinking of the Behringer MDX4600 Multicom. I know it is not the best quality, but that's all we could afford. I suspect it does work with mic level, as the usual is to compress vocals, but I wanted to make sure. In the back there is a switch for selecting +4dBu/-10dBV: This is what confused me. Thank you,Dimitris. Link to comment Share on other sites More sharing options...
Bobbsy Posted April 21, 2008 Share Posted April 21, 2008 Short answer: No. You might get some sound through the unit but it will almost certainly be excessively noisy. The switch between +4/-10 effectively lets you select between "professional" balanced sources on XLR or TRS jack and "domestic" unbalanced sources, usually on phono jacks. The two specified levels represent the nominal "zero" level used by these two systems. Although different in absolute terms, both are forms of "line" level and well above anything a microphone can output. The level coming from a microphone (before a mic pre-amp) will likely be arriving at between 40 and 70 dB less than the line level your compressor is expecting...and cranking things up to correct this will result in muchos noise. Bob Link to comment Share on other sites More sharing options...
dvidos Posted April 21, 2008 Author Share Posted April 21, 2008 Short answer: No.I though so too. Bummer... Ok, plan B: Do compressors in general work with line level and not mic? If not, it means I can search for another one in the same price range. If yes, I can get a two-channel compressor and process the main output of my mixer. We mostly use it for voice reinforcement anyway... Thanks for the quick reply Bob. And a question arises: If compressors in general process line level signals, how do people connect them up for mic process? Using Insert only? I can understand group or matrix or main output, but for single mic channel? Link to comment Share on other sites More sharing options...
paulears Posted April 21, 2008 Share Posted April 21, 2008 compressors, limiters, gates, graphics - everything you see in the foh rack is line only. Connection is always by insert. In the studio, it's more common to wire them via a patch bay so they can be swapped around to where you want them, most connections are still via inserts - although you can wire them directly in to outs and ins if you wish. Mic connection simply isn't what they were designed to do - they'd have to have preamps, phantom power, gain controls etc - making them much more expensive and complicated. It does also make me wonder if you really need a compressor? If your system uses a non-insert capable mixer, what kind of quality is it? many systems that I see don't use the compressors because they aren't really of the kind of quality that would make their use worthwhile. I've got a rackfull of the things, but would own up to not using them very often unless the source material was suitable. Link to comment Share on other sites More sharing options...
Bobbsy Posted April 21, 2008 Share Posted April 21, 2008 To take your last question first, the norm is to use inserts. You haven't specified what mixer you're using but it's quite unusual for any unit used in live sound not to have inserts....even inexpensive ones like Behringers and the Yamaha MG series pretty well all have inserts. Indeed, that might be a direction for you to look--a new Behringer mixer with inserts might well cost less than a new compressor! On your other question, I don't personally know of any dedicated compressors with mic level input--but I'm sure if there are any, other Blue Roomers will dive in. However, what do exist are a number of models of mic pre amp that have basic compression built in. I'll stop short of recommending any specifically since I've not used them personally. Again, others may jump in with experiences. Bob Link to comment Share on other sites More sharing options...
dvidos Posted April 21, 2008 Author Share Posted April 21, 2008 Thank you Paul, Bob.That clarifies things. As for the system we have. I have to give you a little background. The system as I found it, was an 1980's cheap party mixer (pre dj-mixers era) a bit rusted from the humidity. It had two unbalanced mic inputs. Along were some cheap unbalanced condenser mics having a 1/4" phone plug, and a couple of (unbalanced!) extension cables of 3-5 meters. Can you imagine noise and interference? This plugged into a semi-pro, semi-domestic, unbranded, same era, amplifier providing something like 2x125W RMS, then into two domestic speakers with 100W 8" drivers and piezo tweeters. I think the drivers are the car audio style... Now, I came into the picture. My knowledge of pro audio is mostly from the amateur/hobby side, back from when I played in a band. I am not a pro by all means. They asked me to improve the sound system. If possible, to make the distance from microphones to the amplifier longer. The budget I was given was 800 EUR, around 550 GBP. So I purchased a cheap (yes, I regret it now: low quality preamps, no inserts) mixer, having 6 balanced mic inputs, lots of balanced mic cable, XLR plugs, two balanced dynamic cardioid mics and connected it all together. The distance became 30 meters. It was quite acceptable. I could mix from FOH now, and the amp need not be by the feet of the spokesman. But the amplifier and speakers remained problematic. Inadequate amp power vs need for louder voice, led to amp clipping, burning the tweeters. When I was not there, people would turn up the volume, the clip LED would be almost constantly on!. So this year I managed to get the same budget and purchased two 12" full range speakers capable of 300W RMS and a 2x450W amplifier. Balanced input in the amp, proper speaker cables with speakon plugs, speakers on sticks. Much better! The thing is, when a budget is given to me, I should do the best with it, covering the most problematic part. I may not be given any more budget next year. We also got a few Parcans 64, a donated CD player. So I was thinking, half-decent mixer, good amplifier, good mics, well, what's next for better sound? A compressor. Just to clarify, "them" is the council of my village's local organization. A group of people who decided to make something good for the village and indeed managed to do so. Among other works, an open theatre was built. And somehow this rusty party mixer became its console.... and then they saw I knew how to connect it... and one thing led to another... and here I am asking you about compressors! ;) Sorry for the long post. I had to get it out of me! Back on topic,I understand that compressors (and the rest of processing equipment) work on line level. So for now I will leave it as is. Maybe in the future I will add dynamics processing to the main mix output. Thanks again,Dimitris Link to comment Share on other sites More sharing options...
Lufty Posted April 21, 2008 Share Posted April 21, 2008 checkout the behringer shark , it has mic level input , compression & phantom power Link to comment Share on other sites More sharing options...
paulears Posted April 21, 2008 Share Posted April 21, 2008 Dimitris - I really wouldn't bother - processing on the output will inevitably make the thing sound 'louder', not help feedback control at all, and stress your system even more. If you have some more funds coming, save them for other areas - better mixer with more comprehensive eq, better sounding loudspeakers, more mics. signal processing just won't make it better till the overal system quality is high enough to benefit. To honest, the only thing worth putting across the output until you have a topc class system is an eq. Club systems often add gadgets to give "big bottom" - but unless you are into that kind of thing - forget it! Link to comment Share on other sites More sharing options...
dvidos Posted April 21, 2008 Author Share Posted April 21, 2008 If only I had discovered this forum two years earlier!!! ;) Cheers! Link to comment Share on other sites More sharing options...
MarkPAman Posted April 21, 2008 Share Posted April 21, 2008 To answer the simple question that this tread started with, there are some units e.g. like this one, that do have a mic preamp in. So you could run a mic directly into this. Ive got a pair of these & find them very useful , not usually for that purpose but as a lot of gear in a small box - you can patch in and out of each part & so it makes a very flexible tool. However, what Bobbsy & Paul have said is all true. Link to comment Share on other sites More sharing options...
jamesperrett Posted April 21, 2008 Share Posted April 21, 2008 Compressors really need to be used by someone who knows what they are doing - they can easily have the effect of reducing the gain before feedback. If you really need to tame a particular source it might be better to buy an all in one channel strip with decent eq and compression and feed this into a line input on your existing mixer. Cheers James. Link to comment Share on other sites More sharing options...
weatherhead Posted April 23, 2008 Share Posted April 23, 2008 The vast majority of compressors that have a mic level input are either going to be problem solving boxes like the SHARC or uber expensive studio channels. I think you should be considering the mixing stage... as others have commented there's not much point in going for dynamics processing at the stage you're at. Having said that, I have behringer compressors both in our band's live rig and my own collection... and like other behringer gear in this category (rackmount generic live audio gear stuff), I've never had any problems with it, it's great for the price, and has a lot of features Link to comment Share on other sites More sharing options...
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