Not Passing ACX Check Analyzer. I need help with Effects

[Ted R Brown]

Audacity 2.1.2
Windows 10, 64 bit
Not Passing ACX Check Analyzer. I need help with Effects


Equipment:
Audio Software: Audacity 2.1.2
Audio Interface: Scarlett 2i2
High Pass Filter: Shure A15HP
Mic: Blue Spark
Acoustic Treatment: Kaotica Eye Ball

[Trebor]

Not Passing ACX Check Analyzer. I need help with Effects

I don't speak ACX , but how about amplifying it by +6dB ...

try +6dB or +7dB or +8dB

amplify by +6dB in Audacity.png (5.98 KiB) Viewed 797 times

[steve]

You need to apply a little bit of compression and then Normalize to a peak level of -3 dB (or slightly under -3 dB. "Under" -3 dB means "more negative", for example -3.5 is under -3).

[Ted R Brown]

ACX requires the file measure between -23dB and -18dB RMS and have -3dB peak values and a maximum -60dB noise floor.

I have down sized my home and in so doing, I sold my recording booth. (Big Mistake). I cannot get sufficient gain to be recording between -23dB and -18dB RMS. In Mastering the file, my chain was: (1) Equalization, (2) Normalization, (3) Compression. But in using these effects, I haven't found the combination that meets the requirements of ACX.

[steve]

ACX requires the file measure between -23dB and -18dB RMS and have -3dB peak values and a maximum -60dB noise floor.

Your first post shows RMS = -27.6 dB, which is 4.6 dB below the minimum required by the ACX specification and 9.6 dB below the maximum.
Your first post shows -6.9 dB peak, which is 3.9 dB below the ACK specification.

So what you need to do is to increase the RMS (average) level by around 6 dB while increasing the peak level by (only) 3.9 dB.

Make a backup copy before you proceed.

The simplest way to do that is to first amplify the track with the default settings (up to 0 dB, which in this case will amplify by 6.9 dB) which will bring the RMS level up within range, but your peak level will now be too high, so apply the "Limiter" effect with default settings to bring the peak level down to -3 dB. The default settings for the Limiter can be seen here: http://manual.audacityteam.org/man/limiter.html

If you want the peak level a little under -3 dB (could be a good idea because MP3 encoding is likely to push the peak level a little higher, apply the Amplify effect again with a little negative amplification (say around -0.2 to bring the peak level to -3.2 dB).

Most important: How does that sound?

I cannot get sufficient gain to be recording between -23dB and -18dB RMS.

Set your recording level to get a maximum peak level of around -6 dB. If you can't do that then you probably need to get closer to the mic.
-6 dB peak should be close enough to be able to tweak the levels in post production, while still allowing a reasonable safety margin for unexpectedly high peaks that would otherwise ruin the show.

[Ted R Brown]

Thanks Steve...this worked.

This procedure (for this specific case) will eliminate me from applying my usual EQ, Normalization, and Compression? Correct?

And if I can record in the RMS limits required by ACX, then perhaps then I could return to the mastering chain I was using. Correct?

Could you recommend an online class for engineering/mastering? I know there are videos, but is there a teaching program?

Thanks again.

[steve]

In my opinion, the best teacher is "experience" (coupled with reading widely about the subject).