Not Passing ACX Check Analyzer Issue #2

[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

I posted an issue a couple of weeks ago With similar issue. I have set for hours trying to get the Peak level up and RMS to comply with ACX.
ACX requires the file measure between -23dB and -18dB RMS and have -3dB peak values and a maximum -60dB noise floor.

I would sincerely appreciate knowing the mastering that passes ACX.

Thanks again.
Ted

[kozikowski]

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

That's not quite correct. Yes, you have to hit RMS (Loudness) between -18dB and -23dB, the other two are open-ended extremes.

Noise no louder than -60dB when you stop talking and no peak louder than -3dB—ever. ACX-Check is correct.

Are you using SetRMS? Depending on how old these posting are, we changed the recommended process. We never had a good way to force RMS values where we wanted them. Steve wrote a tool that does that, so the process is a good deal shorter than it used to be.

The golden chalice is to read in a very quiet, echo-free room with a terrific microphone and not need any processing past overall volume. I can do that and we recently had a poster who could do that. Live reading will always need a little volume adjustment because the specifications for reading and posting are different.

If you're not using SetRMS, it's still possible to hit it with the other older tools, it may just take a bit longer.

I need to drop out for a bit. It may be easier if you post a sample of your work on the forum.

http://www.kozco.com/tech/audacity/Test ... _Clip.html

You may not have to change anything since you've been shooting for the wrong standard.

Koz

[Ted R Brown]

Thanks Koz for your willingness to assist.

I have tried to follow your instructions in setting up SetRMS. I still can't meet the ACX Requirements.

[Ted R Brown]

I don't see the file I uploaded.

03 Dedication Forum.wav

Sample

(780.05 KiB) Downloaded 67 times

[kozikowski]

It's not quite that easy. I'm working in the field right this second, and I think I'm missing one of my software tools... [email protected]#$%.

You have a distortion problem on top of ACX-Check conformance troubles.

Nice voice, though.

As we go.

I need to write a summary of this instead of dumping you straight into the comments, but this is the AudioBook Mastering document I wrote. Chew on that while I get back home. It's in blocks, so scroll down.

http://kozco.com/tech/audacity/ACXMaste ... ering.html

Koz

[Ted R Brown]

Thanks again...I'm getting ready to watch some basketball...be out the rest of the night.

I look forward to ruminating on your Mastering file.

Ted

[kozikowski]

The submitted clip is AudioBook compliant just as it is. But there is something wrong with it and I suspect the AudioBook people will flag it right away. See where none of the blue waves ever get taller than 0.5 up and down?

Screen Shot 2017-02-04 at 17.25.59.png (9.17 KiB) Viewed 1570 times

That's sound distortion. If you zoom into the waves, you'll see the tops and bottoms get cut off. The waves toward the right in this pix are normal, but ones on the left have distortion. That's called clipping for what the waves look like.

Screen Shot 2017-02-04 at 17.24.21.png (5.22 KiB) Viewed 1570 times

If you do that enough, the voice starts sounding harsh, gritty and crunchy. ACX will bounce that in a heartbeat. That's one of the reasons your Peak volume numbers are so low. They pass, but they're lower volume than they're supposed to be because of the distortion.

Didn't we go through this once?

Koz

[flynwill]

While Koz hikes in from right field I pulled down the sample and had a listen.

Measurement wise it passes the ACX requirements with flying colors.

I would almost say it's too quiet -- did you use one of the noise reduction tools? I don't hear any side effects, but the noise floor is quite good.

But there is something in your process that is clipping. Particularly noticeable in the test clip at "God". So so the first question is: Where are the peaks in the original recording. If they were at "0 db" then it is just a matter that you need to back off the gain knob on your Scarlett. When recording it's good to keep one eye on the recording level meters, occasionally hitting the yellow is good, hitting the red is bad.

If the peaks in the raw recording are at the same -6dB or lower then not only do you need to back off the gain knob on the Scarlett, there probably is a gain knob in the windows control panel that you need to turn up to 100%.

[kozikowski]

We're baaaaack.

Your test for this overload problem is yell (Do Not Blow) into the microphone.

WOOOOOOF!!

A normal microphone system will create tall blue waves all the way from 1.0 up to 1.0 down. The sound meters should bounce all the way to the right and turn red. You are intentionally stressing the system just as a test. It doesn't cause permanent harm.

I bet yours doesn't do that. I bet yours creates a solid block of blue that never gets any taller than 0.5. That's wrong and it can harm your show.

Koz

[kozikowski]

Does that problem go away if you record in stereo? Give that a shot. You may be one of those lucky people that has to record in stereo, delete one track and convert to mono later.

If that's it, then that reduces us down to straight voice quality and ACX issues.

Koz