When should a noise gate be applied?

Question

I produce a weekly podcast and I'm slowly trying to improve my mixing and editing skills to make it sound as good as possible.

The podcast is recorded with me and my co-host in the same room, which results in some background noise from the other person being picked up by the mics, as well as normal background noise from air conditioning, computers etc.

Normally, I apply a noise reduction (I'm using Reaper to record and edit) after recording when I'm editing the show by looping a section without talking and using an automatic reduction to mostly get rid of hiss and other background noise.

Recently, however, I've been pointed at the idea of a Noise Gate to further help with background noise and it seems like it would help with mics picking up the other person talking, knocking the table etc.

I understand the concept of a noise gate, but I'm struggling to work out at which point I should apply it, during recording, or after during editing.

I can see pros and cons for both methods so I wanted to get an idea of what some more experienced people thing.

For the record, my master track effects generally end up like:

• EQ (using a male vocal preset to reduce the low end a bit)
• Compressor
• Limiter

Answer 1

I can see two reasons why you'd use a gate while recording instead of in editing : 1. You're broadcasting live. 2. You're using outboard equipment.

A gate should, generally, be first in your audio chain but in your case you might want to put it after your noise reduction. You never want to put it after the compressor!

If you do it in editing you have quite a few benefits : 1. You can carefully set it up according to what you recorded 2. You can find the optimal place in your signal chain 3. You will have unaltered audio so that if in the future you want to re-release your episode and have better noise cancelling equipment you are probably better off... In Reaper you have the quite excellent ReaGate that should handle all your gating needs but there are of course a multitude of other options.

One thing to think of is that if you still have noticable noise after your noise reduction a noise gate may actually make things worse. The human brain is pretty good at masking uniform sounds but if they go on and off all the time whenever the gate opens and closes it may get more noticable. But for handling cross talk it's certainly the simplest way, unless you want to do a lot of manual editing.

In parallel you should of course also work on improving your recording technique to get the source sound as separated and noise free as possible. Try alternative mic positions. But that would be a different question...

Good luck!

Answer 2

Definitely use the gates on the editing phase, rather than the recording.

I am using gates to avoid crosstalk on a 5-person podcast, all recorded around a table, to 5 separate tracks in Logic Pro. Using dynamic mics

The first time I cleaned up ALL the audio on a 1-hour show myself it took around 10 hours, but now I can do it in under an hour. (Someone else is doing the editorial stuff, of deciding what to keep, my job is just to get a clean recording.)

1. Try to get a consistent volume from each person
2. Try to position everyone across from each other around the table, rather than at one end. And consider putting the loudest voices nearest each other, and vice versa (to maximise separation on each channel)
3. If there is a big variation in level from one part of the track to another (perhaps you changed the gain on a track to avoid clipping, or the person changed their speaking position) fix this with a gain stage ahead of the noise gate, then vary the gain using track automation to compensate- then you can keep a constant setting for the gate.

Listen through carefully, and only worry about fixing the noticeable things (like a cough or a mic stand knock) It doesn't all have to be perfect, as long as it sounds natural, and the law of diminishing returns sets in very quickly. If the gate opens from laughing loudly nearby, but is drowned by the sound from that person's mic, don't worry.

If gates opening and closing are too obvious (perhaps due to background noise, only only some sounds bleeding onto other channels), consider setting up all the gates to always allow a bit of the sound through

Answer 3

During recording and editing(in case you need to record again). There should be three red lights on the mic channel.

Answer 4

I use noise gates in the field for recording depositions. It seems like a great idea for blocking out crosstalk, but you'll run into a snag once you start using them in the field that you didn't anticipate.

In order to block all crosstalk from other speakers in an "inactive" mic, you'll have to set the threshold so high that you'll chop off single-syllable answers /comments for that speaker. The human voice has a very wide dynamic range, and the quietest parts are lower than crosstalk from loud speech. You'll find that you can use gates in the field to block background noise (when nobody is talking) and some crosstalk, but you'll have to accept all mics being on during loudest talking.

Loud rooms are tricky. You have two choices there. First is to back off from the amount of attenuation you use in quiet rooms (I use 12db to 16db there) to something less, so that the gate transitions are less noticeable (I use 6db to 10db at most there with longer release times for more gentle taper). The second way is to use MORE attenuation, but you have to use much more aggressive timing to close the gates faster. Even so, you might still hear some background noise while the gates are open. Loud a/c can sound like a constant rubbing sound while they are talking.

Answer 5

Noise gates obviously are used to help lower noise, during "quiet" passages, for better recordings and to limit feedback.

Also, they limit erroneous material from triggering compressors/limiters and ambiance processors (delays, reverbs).