ACX Dang that noise floor

THANK YOU!!!
I’m going to try to group responses so this doesn’t sprawl all over the place.

1. Oh no! OK, you won’t believe this. Before I submitted the files I went through and processed them to clear the ACX Check. But I did not go back and listen to the results. I listened just now to what I sent them, and it’s awful! The spaces where I’m not talking are utterly silent. It’s terrible!

Sample of the overprocessed mp3s I sent ACX (this sample is from my MD home office):

2. About using the Audiobook Mastering Tools…sigh. I did not do any mastering, at first. I finished recording in March, and sent all the wav files for processing to a musician friend who has a high-level home studio. He did this for my previous 6 books, and they were all accepted right off the bat (I didn’t know that was unusual).

So, last March, I got the mp3s from him and submitted them. That time through, the ACX review email said that the RMS was too low and the noise floor too high. My friend re-processed them, but I decided to hold off on re-submitting, because I’d rather have it go on the market around January-February.

Then I decided to divide the chapters a different way, so I opened the mp3s he’s sent me, split em up, and saved them again as mp3s–not ideal, but I didn’t have the processed wavs, only the raw files and his processed mp3s.

But before sending the files, as I checked them. Even though my friend had processed them, there were problems. The files were failing the ACX check. Some of the opening and closing silences weren’t the right length.

So that’s when I started this forum thread, a few weeks ago. Then I processed all the files to clear the ACX check, and got this review email a couple of days ago. Its lenient, though, and passed the robot only. A human would say that the files sound pretty bad.

3. Original wavs
The original wavs I sent my friend sound pretty good to me. Here are samples, recorded, in the two houses (both on the Behringer C-1U)


4. Windows mic settings Yes, I had the Windows mic gain/boost setting as high as possible, and the Audacity gain as well (perhaps the two are correlated, I don’t know). Even with both set as high as possible, my soft voice was still failing the ACX check. I Amplified it, and then tried to suppress the peak and room noises.

5. Zoom H2 I also have a little hand-held Zoom H2, and last week gave that a try, wedging it in the desk mic stand (w spider shock mount). I think it sounds better than the C-1U, and it gives more options in terms of gain; there’s a 3-way switch on the mic itself. This recording is set on Medium:

Zoom H2 sample wav

6. Publicans Thanks for creating the comparison clip. It’s so much better. It’s funny; my original sounds like the HVAC is blowing air in the background, but I had turned it off for the duration.

7. Here’s the review email I just received from ACX:

ACX Review
Hello,

The ACX Quality Assurance Team has reviewed your recently-completed audiobook, "The First Fruits of Prayer: A Forty-Day Journal through the Canon of St. Andrew ". We have found 2 issues that must be corrected before we are able to process your audiobook for retail sale.

Below, we have listed the requirements not met, the files affected, and our recommended solutions:

Issue: All files contain excessive background/ambient noise and do not meet our noise floor requirement. Please revise all files.

Requirement: a maximum -60dB noise floor

Solution: In post-production, you may use noise gating or reduction to help reduce the noise floor. Please be mindful that incorrect use of this kind of software can lead to poor sound audio. The best way to go about lowering your noise floor is to identify and eliminate the source of the noise. Often it could be the microphone picking up a loud sound from within the room or it could be a gain staging Issue with your recording equipment. Please be sure that any noise emanating appliances (air conditioner, computer fan, fluorescent lights, etc.) are turned off or isolated so the microphone does not pick up the sound. Our recent ACXU seminar Studio Gear Series goes over the importance of sound proofing your recording area. The Mastering topic in our Video Lessons & Resource section contains samples of what a noise floor should sound like.

Issue: Several files contain noise at the start and/or tail end. Please revise all files to be sure none of them contain any noise, loud breaths and/or mouse clicks at the start (before narration begins) and at the end (after the last spoken word).

Requirement: files free of extraneous sounds

Solution: Please remove any extraneous sounds that are found in these files. We have several resources on how to do Editing and QC passes on a production. Learn the Audible Studios method for Quality Control of extraneous sounds and watch a tutorial on audio editing for assistance. Learn Editing and Spacing with Alex the Audio Scientist. Visit our Recording & Editing page to learn about cleaning up your recording.

After you have corrected the issue(s) above, follow these steps to submit the project for review:

Log into your ACX account, navigate to the In Production tab, and select Title from your list of projects.
Select “Edit” next to the files listed above to delete, replace, and upload corrected .mp3 files.
Confirm the files appear in the order they are intended to be heard.
Click “I’m Done”.

Please be aware that the ACX QA review is not an end to end review of your production and you should always do a full edit, QC, and mastering pass before submission. This is important because errors in the audiobook could garner negative reviews on Audible, Amazon, or iTunes which could result in fewer sales.


Regards,
The ACX Team
Visit ACX.com



The H2 recording is far better than the C-1U: much lower noise-floor.
Here I’ve mixed the H2 recording down to mono, DeEssed, DeClicked, & expanded

It passes ACX no problem.

[ I’m nitpicking now:
there is a metallic resonance on “hoping that this”, like the springs on those mic boom arms ringing ]

springs

My Opinion the reason they went to good lengths to explain what was happening was you are an old and valued client. First time readers get more abbreviated comments if for no other good reason there are usually multiple problems and it’s not their job to troubleshoot someone’s studio.

I bet they’re listening to your stuff, looking at each other wondering what on earth happened.

You fell into two other known conditions.

Once you get something working, hold onto it with white knuckles. Now you know why.

If you have continuing problems recording on the computer, stop recording on the computer. As a test, I announced into a Zoom H1n and cranked out an audiobook compliant sound track with no noise reduction, and no processing other than Mastering.

That’s my photo studio. My sound studio is unphotographable—but it is super quiet.

You should know that ACX Check requires 3/4 second of clean background noise to work. If you edited a chapter into chunks, then each chunk needs some clean background sound and that’s even above ACX requiring background noise before and after each chapter.

You should stop posting Maryland stuff. Neither of us lives there any more.

I just got back and am catching up.

Koz

Is your H2 one of these?

https://www.youtube.com/watch?v=7LSbDdZLr1w

If it is, you win the lottery.

Josh recorded the whole first third of his music career on that thing.

https://www.youtube.com/watch?v=QcVec_RPwuc

https://www.youtube.com/watch?v=w5SC1uIxXhk

It’s an H2 and not an H2n, right? Those are going for new equipment prices on eBay.

Koz

TN house wav raw wav won’t work with AC Check. There are moving around and breathing noises at both ends of the performance. There is no clean background noise or room tone.

http://www.kozco.com/tech/audacity/TestClip/Record_A_Clip.html

Use your own words. You don’t have to struggle through contented cows.

Koz

One more. The volume is low. The blue waves should reach more or less half way, to 0.5 every so often. Yours are tiny.

Koz

Two more.

Issue: Several files contain noise at the start and/or tail end.

Thanks for posting the complete ACX messsage. We don’t have any direct relationship with Audible/ACX, so the only way we know what they’re thinking is copies of the field reports like yours.

Koz

We may still be able to pull this out (but maybe not your original readings). Do burn a proper test. We’re on the edges of our seats.

It’s super good to know if you did read it again, it would succeed. Wouldn’t it be a kick in the head if it didn’t?

Koz

Trebor, thanks for producing that comparison of “laryngitis”. I have never used De-Ess or De-Click. I see “click removal” in my Audacity 2.3.3, but not De-Ess. That’s a plug-in, right?

I am wary of tinkering with Dynamics. This sounds good, sounds bigger. But I’m not sure I should apply it like wallpaper over 9 hours of audio–

Koz, thanks so much. Yes, I have a real H2, not a H2N. I was surprised to find that I bought it back in 2010! Handy little guy. It’s so excellent in noisy rooms. I was interviewing someone tall (I’m short) in a noisy room, and had to hold it up to him to record his replies to my questions. I couldn’t hear what he was saying, but the H2 grabbed it just fine.

Here’s the contented cows. I don’t know if it’s a good representative sample as far as my voice goes, since I still have some laryngitis. But of course the room noise etc would be the same.

The mic gain was .58. (ignore the 51 in the file name, my mistake). It still failed the ACX check for RMS–it was 24.4. I am seeing green waves that look healthy, but they must not be quite enough.

I tried an earlier sample at .50, and sat real close to the mic, but that also failed (just barely, 23.3, but there was too much breath & mouth sound).

And I tried the gain at .81, and spoke beside the mic rather than at it, but the peaks were too high, and even the RMS was too high.

I would really like to take those original raw wav files (some recorded in MD, some in TN), and start over, editing them for ACX. Do you think it can be done? The MD files should be OK, since they accepted them before. Should I attempt to use the TN files, or are they hopeless?

Cows (Contented).

It’s perfect.

I applied simple Mastering and it exactly fits the ACX requirements.


Screen Shot 2020-01-09 at 9.24.09.png

Nobody can read RMS (loudness) and Peak to match at the same time. It’s Mastering’s job to get them together. If Noise passes after Mastering does its thing, you win. That’s all three.

Noise isn’t one tool or setting. Noise is the college course.

So that’s the answer to the question of could you read it all again if you had to. Yes, certainly.

You have WAV copies of everything, right? You can’t edit an MP3 without increasing distortion. Your archives and safety backups should all be in perfect quality WAV.

I changed your submission from stereo (two blue waves) to Mono (one blue wave). Select the stereo track with the Select button left > Tracks > Mix > Mix Stereo down to Mono. ACX doesn’t require mono, but it makes them happy.

Do you have any way to post work outside the forum? Our services are nice and all, but here, you’re limited to ten seconds stereo. A file posting or archive service? Something?

============

I like the voice. That’s Lauren Bacall to Humphrey Bogart in “To Have and Have Not.”

“You know how to whistle, don’t you Steve? You just put your lips together and blow.”

How long can you stay exactly that sick?

Koz

Koz: Lauren Bacall, LOL. I wish I could cultivate it, like an actor cultivates exactly 2 days’ worth of chin stubble.

Didn’t they get Andy Williams to dub a song for her? I forget which movie.

Yes, I can easily put these files into my Dropbox and send you a link. Would you be able to take a look at them and see whether they are salvageable? That is my first hope.

(How should I send you the link? Email? Text? Just paste it in here?)

If I have to re-record–sigh, it can be done. My vocal weakness is that, often enough, after an hour or so of reading I get a frog in my throat that won’t go away. (Only when recording, not when giving a speech. Go figure.) But if I have to record one hour a day for 9 days, it’s not impossible.

On my mental calendar: our Lent begins March 1, and the book is designed to be read for the 40 days of Lent (40 short chapters), so it would be great if it could be available before that. Which is why I sent it to ACX on December 3. :frowning:

If seeing ACX comments is useful to you, I’ll paste in below the review letter I got from ACX earlier this year, when I sent in the files in February (and missed last year’s Lent). However I no longer have the files that this letter is based on, since I re-saved my recent edits under the same file names.

So here’s ACX’s review of the submission last February:

[You’ll notice that the noise floor evaluation says it applies to “all” of the files, but the RMS evaluation applies to “17 files.” They attached a “graph” showing which files. I opened it. It was not a graph, but a simple Courier-font list–of all the files. ]

<<Hello,

The ACX Quality Assurance Team has reviewed your recently-completed audiobook, "The First Fruits of Prayer: A Forty-Day Journal through the Canon of St. Andrew ". We have found 2 issues that must be corrected before we are able to process your audiobook for retail sale.

Below, we have listed the requirements not met, the files affected, and our recommended solutions:

Issue: All files contain excessive background/ambient noise and do not meet our noise floor requirement. Please revise all files.

Requirement: a maximum -60dB noise floor

Solution: In post-production, you may use noise gating or reduction to help reduce the noise floor. Please be mindful that incorrect use of this kind of software can lead to poor sound audio. The best way to go about lowering your noise floor is to identify and eliminate the source of the noise. Often it could be the microphone picking up a loud sound from within the room or it could be a gain staging Issue with your recording equipment. Please be sure that any noise emanating appliances (air conditioner, computer fan, fluorescent lights, etc.) are turned off or isolated so the microphone does not pick up the sound. Our recent ACXU seminar Studio Gear Series goes over the importance of sound proofing your recording area. The Mastering topic in our Video Lessons & Resource section contains samples of what a noise floor should sound like.

Issue: 17 files have a low RMS and are too quiet: Please see attached document for a graph of affected files.

Requirement: files measuring between -23dB and -18dB RMS

Solution: Please raise the overall RMS level of each file to within our requirement. For example, if a file’s RMS is -30dB RMS, it must be raised +8dB to be within our -18dB to -23dB RMS requirement range. Learn Mastering with Alex the Audio Scientist.

After you have corrected the issue(s) above, follow these steps to submit the project for review:

Log into your ACX account, navigate to the In Production tab, and select Title from your list of projects.
Select “Edit” next to the files listed above to delete, replace, and upload corrected .mp3 files.
Confirm the files appear in the order they are intended to be heard.
Click “I’m Done”.

Please be aware that the ACX QA review is not an end to end review of your production and you should always do a full edit, QC, and mastering pass before submission. This is important because errors in the audiobook could garner negative reviews on Audible, Amazon, or iTunes which could result in fewer sales.>>

an actor cultivates exactly 2 days’ worth of chin stubble.

That’s not the hard part. The hard part is maintaining that growth through five days of shooting. Makeup gets a warning if you’re planning on shooting out of order. Today, we’re going to shoot the establishing scenes from the beginning of the show.

I’m not sure where to go with this. We don’t know what Maryland Pro did to your first six books and we can’t take them apart to find out. That’s why we insist that you post uncorrected, clean work for inspection on the forum.

I suspect we can master what you did to passing for submission, but there’s little chance they’re going to match the older work. That’s going to come up. That’s their phrase “… you should always do a full edit, QC, and mastering pass.” Everything needs to match.

I need to drop for a while.

Koz

Koz: Oh, so that’s why you went to California!

Thanks, everyone, for all your help.

that’s why you went to California!

I took a wrong turn in Arizona. Wait. What is this warm place with palm trees and surfers?

I’m sending you high quality MP3s of your test clips. I used the classic DeEsser…

…according to these settings.


Screen Shot 2020-01-09 at 17.14.06.png
I used the mastering tools like this.




From here.

The two states are different. Only Tennessee needs the DeEsser.

Here’s how mastering goes.

====================

Maryland/Tennessee Matching
2019-01-09


FF MD

Audiobook Mastering
Effect > Noise Reduction 9, 6, 6


FF TN

Audiobook Mastering
Effect > DeEsser -20.0, 10.0, 2500.0, 8000.0, 10, 5.0
Effect > Noise Reduction 9, 6, 6

======================

The two groups more or less match with TN being slightly more noisy than MD. Both pass. We hope nobody will notice. You can’t just crank up the Noise Reduction because that may affect your voice.

Koz

I don’t remember, have you ever used Noise Reduction? It works in two swipes.

Drag-select some portion of clean background noise. Quarter Second? Half Second? No shuffling, breathing, coughing, etc. Just background sound.

Effect > Noise Reduction > Profile.

That lets Noise Reduction “sniff” the noise like a good dog.

Then you select the whole track and Effect > Noise Reduction: 9, 6, 6 > OK.

That’s the actual reduction part. Gentle Noise Reduction is considered 6, 6, 6, noise reduction of the beast. You need a little more of a push than that so 9, 6, 6 is stiffer reduction. If you go too high, the noise will go down, but your voice will start to sound like you’re talking into a wine glass.

I posted the abbreviated version of Mastering in yellow highlight. If you look at the exhaustive writeup instead, it will tell you how to get the tools you don’t already have.

So yes, if that’s close enough for ACX, you can mix MD and TN readings. Quick word, if you can’t restrain yourself and want to apply additional filters and corrections, you will have to apply them to all the chapters and make sure they don’t conflict with the unique Tennessee settings.

Koz

You weren’t expecting a one-button-push solution were you?

This is less terrible than it looks because many of the tools hold their settings. For example, if you set up Effect > Limiter once, the second time, it’s Effect > Limiter > OK. I can whip through Mastering a short test in about 12 seconds. DeEsser holds its settings, too, but not so Noise Reduction. If you close Audacity anywhere in the process, Noise Reduction’s eyes will roll up and it will forget its profile.

There is a one-button Mastering published. but I’m not fond of it because the first step, Effect > Filter Curve is not unconditionally stable. You won’t know if it gets it wrong—it will just start producing bad chapters.

There is an up side. If all the chapters are of that quality, this is one known process to make them pass.

Koz

You were never exposed to the full glory of Mastering and voice corrections. Now you know why we strongly recommend a well-behaved microphone and studio. With my Zoom H1n or your H2, it’s possible to record in a dead quiet, echo free room, transfer it to the computer, cut it down, master it and submit it.

No other corrections.

Go make coffee.

Koz

Yes, you can get a DeClicker plugin specifically for Audacity here … Updated De-Clicker and new De-esser for speech
( Some store-bought DeClicker plugins work in Audacity, they are simpler to use & faster, but co$t).


I used the louder end of the ACX specifications for both RMS & peak.
For the the best signal-to-noise ratio for the consumer, the RMS volume should be close to the loudest permissible value.
Could maintain RMS near maximum permitted, but reduce the peak from -3dB to -6dB if you prefer less dynamic-range …

Wonderful, thanks so much. Now I know what to do. I lean toward doing the least tinkering possible, but it was helpful to know that you can’t have perfect ACX Noise Floor and RMS right from the raw take. It will always need a little help.

I have my work cut out for me this weekend–2 Introductions, 40 short chapters, and 3 Appendices. But at least I know what to do! Thanks so much for showing me the way out of the thicket. I’ll be back after I’ve done some work on it (and if I run into anything confusing).

–F

It should all be confusing. There are only three people on earth trying to match two different studios.

Koz