Metallic ring? after high compression using SC4

Hi – Thanks to all those who support us new audio editors. I’m editing voice, and we have a hearing impaired end user who has asked for maximum amplification. I’m using SC4 in Beta, which I love. I have it running at the rails, minimum attack & release times, 8:1, -17dB threshold. Once I’m done I do a hard limiter to say -15dB or -17dB, then amplify fully all the way up to zero. Finally I do light noise reduction, get a few seconds of silence, sounds like hiss, then do a very light noise reduction. The final recording is nice and loud, and the end user is very happy with the compression and the volume. The problem is that I get a sound that is hard to describe, kind of a ringing or a tinny metallic sound that I haven’t figured out how to eliminate. It seems to come out most when the voice says the letters “s” and “u”, not with consonants. I’m not sure which of the things I’m doing is the culprit. I tired plotting the frequencies and noticed a ~7K peak, but supressing that didn’t seem to help. If I can fix this I’m in good shape.

Thanks again to all those helpers like stevethefiddle and alatham, you are very dedicated, and I’m very sincerely grateful to all the time this takes to respond and help us out. These talks go on I-tunes as a Buddhist Zen podcast, so I hope they serve mankind. I fold my hands and bow in sincere gratitude!

Thanks again, Glenn Harvey

Note – I tried adding the sound clip, this foruc doesn’t look like it allows that, seems funny for an audio editing forum. Anybody know what to do or what I’m doing wrong? Thanks, Glenn

It’s difficult to be sure without hearing it, but I suspect that your “metallic ringing” is the result of artifacts generated by the Noise Reduction process.

When you compress the hell out of a recording, the quiet sounds, including any hiss, become considerably louder, and trying to remove relatively high levels of noise is prone to causing metallic ringing sounds. You will probably get better results if you do gentle noise reduction before the compression - the final result may have a little more his, but will hopefully be a “cleaner” sound overall.