compressor placement

does it matter where i put my compressor

i’ve been using ntrack 3.3 for quite a while with pretty good results. i finally switched back to using it after switching to anther program for a while. anyway, now that i’m back to using it i have quite a bit of hissing in the signal that i record from my condenser mic. when i used ntrack in the past i had my condenser mic going to my pre-amp to my soundblaster sound card. at that time, i had hiss in my recorded signals but it was very minimal and easily taken care of with a noise gate. now that i’ve switched back to ntrack i’m using the same condenser mic and pre amp, but now i’ve added a tascam us-428 and a behringer hardware compressor (the autocom pro). now my recorded signals have a significant amount of hiss in them. i have minimal experience with hardware compressors and wanted to know if it matters where i place the compressor? currently the compressor is sitting right beside my PC. could it just be the compressor settings that is causing the problem? thanks for the help.

Well I guess the simplest test would be to remove the compressor from your signal chain and see what the difference is.

If it is adding hiss it may just be a setting… I have a Berry Autocom (I think the model is 1440 or something liek that) and it doesn’t seem overly noisy to me…
Maybe a dodgy connection in the unit though… not sure what your hissing is like…

Also does the tascam have gain controls on the inputs? It maybe that you have the gain set too high on them which may give you some hiss.


My experience has been that if I have any noise (and I mean ANY noise), that a compressor only amplifies it, and most times, significantly. I’ve done a closed track (kick drum) and found that the noise of the cables, which wasn’t even apparent at the time of the recording created enough hiss that if I over compressed the track (say 5:1 or better) then I could hear significant hiss.

My suggestion would be along the lines that Rich describes:

1. Identify the source of the hiss (I’d take a hard look at the pre-amp – I was able to reduce hiss by about 10db+/- by removing mine altogether)
2. Clean the track up before compressing (although it would seem that you’re really interested in compressing it on the way in). Look into a de-noiser.
3. Perhaps try the compressor as a side chain instead.
4. Lastly, if you’re recording open (meaning you’re capturing the room noise), examine your room: Loud computer? Air vent too close to the mic?
5. Check your mic settings, if applicable. Do you have a pad on the mic? The idea being that you want the mic to be hot enough to pick up the source with as little room noise as possible.

My two cents… :;):

It all depends on how you’re using the compressor.

The location of a compressor in the signal chain is very important, but for hardware compression, you have it in the typical location. The physical location can matter too, but if you were getting noise due to location, it would be buzz more than hiss or white noise.

In general, I feel that an outboard compressor is unnecessary and counterproductive when recording digitally with a decent 24-bit soundcard. Now, there are significant exceptions to this, but most involve limiting, not compression.

There are 2 reasons to use compression:

1) Aesthetic reasons: because it makes the track sound better, disregarding technical issues like S/N ratio.
2) to keep the signal in the green range while recording, to maximize the S/N ratio.

The first purpose can be served by either outboard compressors or plugins – but you can’t undo what an outboard compressor does, so generally it’s better to do this using a plugin. The second purpose can only be done using an outboard compressor, but it’s no longer necessary in most situations (especially for the home studio).

In the old days of tape recording where a 60dB S/N ratio was reasonable (early 70’s), outboard compression was pretty important to get a good S/N ratio in the playback signal, especially for parts with a wide dynamic range (e.g., piano solo, or vocal part with both very loud and very soft passages). Engineers who recorded back then and for the next 10 or 20 years often used outboard hardware compressors because they were necessary, and by the by learned that some compressors, when set up correctly, also imparted a very good tone to the recording.

As a result, there are a number of engineers and home recordists who like outboard compressors even when recording in 24 bits – they LIKE the sound of their compressors, and know how to use them. I have no argument with these people: they know what they want and how to get it.

But with today’s recording S/N ratios of 100dB or so, compressors are just not necessary to preserve the detail in a dynamic performance. Limiters or compressors set up for primarily limiting purposes, still serve a very useful purpose in recording, to handle cases where the engineer didn’t leave enough headroom – to save a great performance that would otherwise be a “do-over”. Or to record a never-to-be-repeated performance or a live act.

These days, in the home studio especially, outboard compressors can be handy but they’re not necessary by any means – and they can cause problems as you’ve seen. Proper compressor setup can help avoid this. But I suggest you simply remove the compressor and record without it. Learn to recognize situations when it would be helpful and use it then. This is especially true if you’re recording yourself: you should learn to control and use dynamics in your performances in a way that records well, and then adjust as desired using plugin compressors. When recording others, especially untrained vocalists, it’s another matter, and judicious use of limiting can save a good performance. But use of an external compressor shouldn’t be a matter of habit. (Except, of course, for those folks who know & love their compressors and know – by experience – when to use 'em and when not to, and how to set 'em up for a given purpose.)

I agree completely with what Rich and Bill said, as well. You may have a source of noise here. If it’s nice clean hiss, it’s usually a gain-stage problem: not running each piece in the signal chain in its “green” range. Either that or just overusing the compressor.

Finally, when you use a compressor and noise gate, the noise gate generally has to be in front of the compressor, so that silent parts are silent. In cases where it’s an outboard compressor and a plugin limiter, though, that’s not possible. The crucial question is this: is the noise audible just in the gaps between phrases, or is it audible during the phrases?

If it’s only audible in the gaps, then you’re probably just compressing too much: lower the ratio and re-adjust the threshold. If it’s audible during phrases, then you have a real noise problem – most likely a gain-stage issue.

HTH :)

Quote (RichLum @ Dec. 06 2005,23:32)
Also does the tascam have gain controls on the inputs? It maybe that you have the gain set too high on them which may give you some hiss.


That was the problem. The sound is flawless now. Thanks for all the help.