Odd microphone hiss during Podcast

Report · Aug 03, 2017

Hi All,

I've scoured the forums and discussions to see if anybody is having the same issue as me but I can't seem to find any. I'll try to explain it and see if anyone can help.

I recently got some new equipment to setup a podcast at my work. I'm no audio engineer but I was able to set it up and successfully record our first podcast. I have 4 Audio Technica BPHS1 Studio headsets that I use as mics. I feed those into a Tascam US-4x4 Audio interface that then feeds via USB into Audition to record.

I was able to record 4 guests speaking just fine, no problems there. Audio sounded great. My problem is playback. When I playback the audio I get a strange hiss that only comes up whenever someone talks- its not a background hiss (like an AC unit) or constant hum- it's almost like it's attached to the vocals themselves. When I was recording it was crystal clear, but on playback and on the mixdown .wav file, the hiss is there.

So at first I thought I had a bad mic and I started soloing some tracks to identify which mic was making the noise. Here's the thing- when I solo a track the hiss is gone. Each mic independently sounds amazing but when they are played at the same time, I get that weird hiss that comes in and out as they speak.

Is this a hardware issue? A playback issue? A mic setup issue? Like I said the audio sounded perfect during recording.

Settings for Audition record if interested: Device class is set to ASIO and sample rate is at 4800 Hz

I feel like there is something that I am overlooking but I just don't know what.

Any help would be appreciated!

Report · Aug 03, 2017

How far up do you have to turn the input gain on the Audio Interface? I notice that the headset mics you use have dynamic capsules which often require the mic pre amp to be turned up pretty high for normal levels. Having 4 identical mics all turned up could add a cumulative amount of hiss.

The other thing I wonder about is whether the headset has some form of noise gate--the blurb says it's designed to be a communications headset and, while I can't fine mention of noise gating in the spec, this is not unusual on comms headsets. If so, the mics would be completely quiet until the mic picks up some noise.

Report · Aug 04, 2017

https://forums.adobe.com/people/Bob+Howes wrote
The other thing I wonder about is whether the headset has some form of noise gate--the blurb says it's designed to be a communications headset and, while I can't fine mention of noise gating in the spec, this is not unusual on comms headsets. If so, the mics would be completely quiet until the mic picks up some noise.

But each channel sounds fine on its own, and the spec doesn't mention anything about a built-in squelch control...

Any chance that you can provide a link to a small section of the combined result, illustrating the problem? Preferably in the form of an uncompressed wav file. Putting the file in Dropbox, and getting the public link to it and posting that would be fine.

Report · Aug 04, 2017

Hi Steve,

Here is a link to an audio sample. It's about a min long. Obviously listening with headphones is the best way to hear what I'm talking about. The hiss is on the whole clip but it's really obvious at :57- when the speaker's sentence ends, this hiss clearly drops out, then comes back as he speaks again.

Dropbox - Podcast audio clip.wav

Let me know if that works.

Report · Aug 04, 2017

There is no hiss that I can see or hear anywhere in the audio clip that you have provided even when playing back with the clip amplified and played back at very high volume. It is a very clean recording. So it is a bit of a mystery as the noise doesn't appear to be actually recorded into the audio file. It must be something in your monitoring chain. How are you listening to the output of Audition? What audio interface are your headphones plugged into?

Report · Aug 05, 2017

Actually it is there at the 57sec point - but it's a very small drop. Audition's behaviour is absolutely linear, so whatever is causing this (assuming no processing of any sort is taking place) is possibly in the Tascam, although there's no obvious reason that I can see unless there's noise modulation in the preamps. But if there was, that would show up on an individual channel, so it's unlikely to be that either.

Can you tell us exactly how you've got Multitrack configured to make these recordings and play them back?

Report · Aug 04, 2017

I actually only have the input gain up halfway on all channels- if I go any higher it's way too loud.