Increase RMS while holding down peak levels?

Selek

New member
Hi all,

A family member has finished recording an audiobook for ACX, using a home studio set up for him by professional audio engineer. Most of the chapters comply with ACX requirements, but a few need adjustment. In particular, he needs to increase the RMS level of the chapter without unduly increasing the peak levels. (He used a limiter while recording in Studio One, and the limiter was set to keep the peak below a certain level; mostly that worked, but in a few cases not.) He can come close to doing this, using Izotope RX 7's leveler, but when he gets RMS to the proper level, the peak level is a little too high -- -0.5 db, say, which is slightly higher than ACX requires. Is there more he can do to adjust the peaks, short of re-recording entire chapters?

I did some audio editing years ago, and I dimly recall directly editing peaks to "quiet" them down -- just scrunching the peaky part of the waveform with my mouse. But I was using Sonar, which I'm not sure even exists any more. Any suggestions on what he can do?
 
You can use iZotope's Ozone's Maximizer with True Peak checked. But, if you're trimming a lot at the top to get peaks down, you probably want to be sending the stream through a bit of compression first so the limiting is more natural.
 
Thanks for your helpful reply. Hmm, I'm not sure he owns Ozone, but I'll ask. In any case, I'll pass on that info. Thanks again.
 
I’d say the same thing about any limiter, meaning if the limited waveform exhibits a real flat-top, clipped look (though not “clipping”), it might sound better if it’s smoothed out and level adjusted with a compressor before limiting. There may be genres where just the limiter is what you want, of course.

If the peak after limiting is too high lower the limit so it ends up where you want it. Some besides Ozone may have a true peak option.
 
I’d say the same thing about any limiter, meaning if the limited waveform exhibits a real flat-top, clipped look (though not “clipping”), it might sound better if it’s smoothed out and level adjusted with a compressor before limiting. There may be genres where just the limiter is what you want, of course.

If the peak after limiting is too high lower the limit so it ends up where you want it. Some besides Ozone may have a true peak option.

Many thanks! So far using a compressor seems to be helping a LOT! Most of the files are now in acceptable format. I really appreciate the help!
 
Slap me if I am being silly here but...IF the peaks are just 0.5dB too high in places why not just drop the level of the whole thing by say 0.7dB?

Dave.
 
Slap me if I am being silly here but...IF the peaks are just 0.5dB too high in places why not just drop the level of the whole thing by say 0.7dB?
That would take care of the peaks but also lower the integrated LUFS, which was, IIRC, what the target was. Of course if the target is -14.0 and you end up at -14.5 (to get the peaks down) that might be fine in many cases.
 
That would take care of the peaks but also lower the integrated LUFS, which was, IIRC, what the target was. Of course if the target is -14.0 and you end up at -14.5 (to get the peaks down) that might be fine in many cases.

Yes, I did understand that Kieth and thank you for being gentle with me! I just thought "HALF a dB?! cannot see that being crucial?

Dave.
 
ACX is stringent with its specs:
"Each file must measure between -23dB and -18dB RMS.
Each file must have peak values no higher than -3dB.
Each file must have a noise floor no higher than -60dB RMS.
Each file must be 192kbps or higher 44.1kHz MP3, Constant Bit Rate (CBR), Mono."

Their algorithm is pretty strict and unforgiving.
Dale
 
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