ACX lab report - question about beginning and ending silence

Hi - I’ve recorded my audiobook and mastered it to fit the ACX specifications. When I upload it to the ACX lab, it says there are no problems. But when I download the report, one of the columns says “Found beginning/ending silence.” The answer it gives is “False.”

I’m not sure what this means, especially since I have other audiobooks accepted by ACX that were done by a professional reader. I ran chapters from two of them into the ACX lab and they both said false too.

When I record, I allow extra silence and just then cut it off after mastering to be the correct amount.

Am I doing something wrong or is there a problem with the report?

Thanks!

They want at least one second of near-silence (“room tone”) at the beginning and end.

They will reject you for “dead digital silence” (but they don’t say how quiet is too-quiet) or for excessive room noise (above -60dB).

ACX Requirements:

Hi - thanks so much for your reply. Sure do appreciate it!

I have the required amount of silence at the beginning and end. I leave a good bit of silence on both ends before recording. Then I master the whole thing and cut off what I don’t need from the beginning and the end. So the silence there is mastered.

My noise floor is generally between -70 and -73 after mastering.

Am I supposed to take off that mastered silence and substitute a recording of unmastered room tone from my recording area? Haven’t ever seen anyone in the videos doing that.

Also, why would my professionally done audiobooks which were accepted by ACX previously also get the “false” reading on the spreadsheet?

Is there any chance that false actually means something else - like okay - on this sheet? It’s all very confusing!

Has anyone else gotten this info from ACX AudioLab on the spreadsheet download?

Lisa

A note about the wording. you do not have silence. You have Room Tone or background sound if you did it right. They, and Audacity ACX-Check, will flag if you actually did put silence in there.

Do you use a Noise Gate? That can create actual silence within a theatrical reading.

Another note. Last I checked, ACX Lab does not check noise. Did they on your evaluation?

Another another note. The audiobook you listen to at home is different from the one that the author sent. ACX applies a processing step—and sometimes they mess it up.

What are your actual steps between reading and creating the MP3 for submission.

Koz

Yes. They will reject you for dead silence. Digital silence is minus infinity dB but like I said I’m not sure how low you can go. -80 or -90dB might be OK but I’m just guessing.

…You probably haven’t seen videos of people adding pure-digital silence either. :wink:

I dunno! It confused me too!

Hi friends - thanks so much for your responses!

Here are my steps after recording -

Normalize
Noise reduction
EQ filter
De clicker
De esser
Compressor
Normalize

With these steps I am at -3, approximately -20, and approximately -70 for every file.

I do this to each entire file. Then I cut off from the beginning and end to make it the right length. I also have some of this “tone” from that area in my copy buffer and use it between sentences if needed.

On the report that I downloaded from ACX - you are right - they don’t list the noise floor. Here are the columns they do list -

Run Time (hh:mm:ss)
RMS (dB)
Peak (dB)
Bit Rate (kbps) VBR
Sampling Rate (kHz)
Found Beginning/Ending Silence
MP3 as WAV File Type Check

It’s the “Found beginning/ending silence” one that is false. Since I didn’t use actual silence but the mastered room tone instead, maybe it is false because it isn’t actual silence.

This would make sense considering my other professional audiobooks, which also registered false. I have the files that she uploaded to ACX, which I used for this test. Not sure about any process ACX might have done afterward to them.

So what do you think? Is the issue that I don’t have silence, which I’m not supposed to have anyway?

Thanks!!

Lisa

I understand they send the chapters to some dark, forbidding place where someone actually does apply Blackness of Space noise reduction.

None of the audiobooks I bought have Room Tone back there.

Koz

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