Hi, I have an M-audio 2 channel USB recording interface, an MXL recording mic and a Behringer Pro-XL Autocom MDX1600 Compressor/limiter. I am also using Sonar X1 Producer Expanded. My question is how should I route my mic signal? Should I go to the Behringer first then the M-audio, or should I go to the M-audio first then the Behringer? Thanks.

the compressor should come after the preamp and since your preamp is inside the m-audio usb soundcard, it's not easy to include it in the signal path.  doing so would include A/D then D/A then A/D conversion and you'd be hurting your signal by doing that.

I would advise just leaving the compressor out of the signal path in this situation.  you can record at 24 bit, just turn the gain down on the mic input so that you're not clipping when you record and you can add compression in Sonar after the recording.

I would go to the Behringer first so you can do any compression/limiting you want to do and then to the MAudio device as its an audio interface between whatever audio device you have and the PC. 

The Behringer doesn't have a mic preamp. Cannot plug mic directly into Behringer.  Use M-Audio insert or what Beagle said: Plug mic into the M-audio and don't use the Behringer. Add compresssion to the track after it has been recorded using a plugin.   

Thanks for your reply. One more thing I guess I should have added earlier; my M-audio interface is the FastTrack Pro and it includes the ability to do "Inserts" on the unit. I have never used these "Inserts" before. Would this be a case where I could run the signal from the preamp, through the Behringer then back into the m-audio before any conversion? I have historically done as you suggested but I was hoping to make it easier to record vocals and get a better signal by adding this compressor/limiter. Thanks.

I have a Fastrack Ultra 8R.  Do you have the MAudio Control Panel with yours?  I think the routing can be done in the Control Panel (I've never tried it). 

I've done some limiting (before my audio recording interface unit) but not Compression.  If I wanted to do Compression I would do it within Sonar with a VST plug-in.   My 2 cents is do as little to the signal as you can when recording and then do whatever after its been recorded.  If its recorded with, for example compression, and after its recorded you find out there is too much the only real option is to re-record the track.

I just looked up the Fastrack pro. 
Yes, it has inserts and this would be a good way to connect the Behringer into the M-Audio. You would need a cable that has one TRS (tip,ring,sleeve 3 conductor) 1/4 inch plug on one side and two TS (tip,sleeve 2 conductor) 1/4 inch plugs on the other side. This type of cable is usually called an "insert cable" or "insert breakout cable". 

Plug the mic into the M-Audio. Connect the TRS plug to the M-Audio "insert jack". Connect the other two 1/4 inch TS plugs to the appropriate "line in" and "line out" jacks on the Behringer.

The insert cable you need looks like this:
http://www.sweetwater.com/store/detail/STP201/

I will respectfully disagree a little with my colleagues here.

plugging a mic into this compressor will, IMO, likely cause noise and distortion after sending the output of the compressor to the input of the m-audio.

the reason is because the input to the Behringer MDX1600 is either +4dBu or -10dBV, both of which describe LINE level inputs (either consumer or pro audio).  The microphone level is very low comparatively. 

from Sweetwater definition of Mic Level:
The level (or voltage) of signal generated by a microphone. Typically around 2 millivolts. Compare this with the two normal line levels (1.23 volts and .316 volts), and it becomes apparent just how much amplification is going on in a microphone preamp, and why it is essential that preamps be of as high quality as possible!

So the output of the microphone is so small compared to the input level expected on the compressor that the result will likely cause noise/hiss or distortion to be added to the signal.  So I never use a compressor BEFORE the preamp since the output of the preamp is LINE level and is designed to be sent to the compressor.

All this to say this is only a consideration for dynamic mics anyway.  A condenser mic won't even work at all if you plug it directly into the compressor because the compressor does not have phantom power available on it and the preamp will not send phantom power THRU the compressor to the mic.

you could use an external phantom power device to power the mic BEFORE the compressor if you want, but that adds another expense of buying the phantom power supply and you still will have the problem of having a MIC level signal being input into the compressor expecting a LINE level signal.

I would not recommend plugging the mic directly into the compressor at all.  I'm sure there are people who have more experience and knowledge than me who would disagree with me, but my recommendation still stands.

the use of the INSERTS on the m-audio would be something you could do.  you would simply connect the compressor inputs and outputs to the appropriate send/receive I/O on the m-audio. 

the only problem with that would be figuring out the routing in the m-audio software, as Fireberd said, but it is do-able.

however, I would still just leave the compressor out of the loop completely in your case and add compression in sonar after the fact.  just keep an eye on your levels and make sure you don't record too hot or you'll have to re-record because compression won't fix digital overs.

if you want to use the compressor in a traditional gain staged scenerio, you'd need to purchase an external standalone preamp to plug the mic into, then to the compressor, then to a LINE input on the m-audio.  that would be the ideal way to connect it.

Beagle is correct about not plugging the mic into the behringer compressor -- you can't do that.
The Behringer doesn't have a mic preamp. It is line level only. I thought it had a mic preamp,  my bad.

Try the insert method previously outlined  if you are keen on using the Behringer.
Again, as Beagle pointed out, it is better in the long run to just plug into the M-Audio and add your compressor, de-ess, etc later as a plugin.


The inserts are standard analog hardware ports and don't need to be configured. From the manual:


"28. Inserts 1 and 2 (Insert 1 / Insert 2) – These 1⁄4” TRS jacks are configured to connect to an analog outboard effect (compressor/limiter, delay, reverb, etc.), inserting the effect between the preamp and the A/D converter. These inserts are only active when a connector is inserted, and are otherwise bypassed. The TRS jack is configured as follows: Tip=Send; Ring=Return; Sleeve=Ground."

mikedocy



The inserts are standard analog hardware ports and don't need to be configured. From the manual:


"28. Inserts 1 and 2 (Insert 1 / Insert 2) – These 1⁄4” TRS jacks are configured to connect to an analog outboard effect (compressor/limiter, delay, reverb, etc.), inserting the effect between the preamp and the A/D converter. These inserts are only active when a connector is inserted, and are otherwise bypassed. The TRS jack is configured as follows: Tip=Send; Ring=Return; Sleeve=Ground."

good info there!