Trying to meet ACX specifications

[chuckyocum]

Alice2raw102918.wav

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Attached is a raw clip using a Toshiba TECRA A50-A, 64-bit, running Windows 7. Boom-mounted Blue Yeti connected directly to the computer. Recording done in a Whisper Room SE2000 series, with computer outside the room. Whisper room located in a totally-enclosed, windowless internal office on 9th floor of an office building. Whisper room DOES contain metal music stand draped with towel, and an undraped wooden table on which is located a computer keyboard and mouse. Thanks to you, I was able to load the ACX plug-in. When I tested the raw clip with the ACX check, with recording level at one-quarter, peak level was -20.0 dB (passes), RMS failed at -39.1 dB, and noise floor passed at -61.6 dB. I did several clips at recording level set at midpoint, but the RMS AND floor test failed. And at high recording levels, the RMS passed but the noise floor really failed. So I would sincerely appreciate your analysis and any suggestions.

Thanks very much!

Chuck Yocum

[kozikowski]

Burn the chair.

That is without question the loudest chair I've ever heard.

"Chapter one" [SCRAAAK]

I can hear chair noises all throughout the performance and it's killing the noise measurement.

Burn the chair. Just take it out back of the house and set fire to it.

Then make a new test recording. If you're following the test clip process, it's not kidding about freezing and hold your breath for that two seconds.

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

Koz

[Trebor]

Alice2raw102918.wav (1.68 MiB)

Your signal is WAY too quiet.

recording level at one-quarter, peak level was -20.0 dB (passes)

That explains why it's quiet : the maximum peak value permitted by ACX -3dB , not "-20.0 dB".

The RMS value permitted by ACX is in the range -18dB to -23dB , (i.e. about -20dB).



Once you turn up your recording level so you have peak volume values of about -6dB that should solve a lot of your problems , ( the signal-to-noise ratio should become better ).

[kozikowski]

Do that after you burn the chair. That screeching noise is not going to go away with Audacity adjustments.

Koz

[chuckyocum]

WOW! Thanks very much! I will have a chair-burning ceremony today. And should I drape the wooden table?


Chuck

[kozikowski]

And should I drape the wooden table

I would. Reflections from the table can affect the timber of your voice. The drape also suppresses table thumping and script shuffling noises.

In addition to suspending the microphone, do you have a "spider" vibration isolator and pop/blast filter?

This is a fully outfitted "studio."



There's a moving blanket on the table and that white spider thing prevents vibrations from the floor from getting into the microphone.

The black tennis racket suppresses breath sounds and "P" pops.

This is a little Hollywood because you would never place the microphone that low and that arrangement only works with quiet Macs. That design is after an actual instructional video on the ACX web page. They were using a soundproof room somebody built in their house. Also, no studio I ever saw had the cables arranged that neatly.

Starbucks is optional. Coffee Bean and Tea Leaf works , too.

Koz

[kozikowski]

computer outside the room.

The regular Yeti is a USB microphone. How long is the connecting cable? Audio doesn't like going down long USB cables. If you have troubles with clicking, popping, snapping or small sections of sound actually missing, that cable is the first place to look.

Koz

[kozikowski]

Missed a step. We publish Audiobook Mastering 4 which is basically three tools that push your presentation into ACX technical compliance—except for noise. There is another whole series of postings what to do if you fail noise.

viewtopic.php?f=64&t=96103

Also note after all this fuss, you only have achieved technical compliance. An ACX submission still has to pass Human Quality Control where your submission may die if can't read.

There is also one slightly more exotic failure. USB microphones may have a failure I've called The Yeti Curse (turn the volume up a bit).

http://kozco.com/tech/audacity/clips/US ... neClip.mp3

That can prevent you from passing ACX Noise and it can kill Quality Control Acceptance. It doesn't submit to Noise Reduction well and it's difficult to get rid of.

Also note that plain ordinary Yeti and Professional Yeti are the same thing. Yeti Pro® is a completely different microphone (at twice the cost) and as far as we can tell, doesn't have that noise problem.

Koz

[chuckyocum]

Thanks very much, Coz! I'll start with the chair and table drape, then rerun the ACX test. (I'll also substitute Folgers Black Silk for the Starbucks...)


Chuck

[chuckyocum]

coz, this was done with new chair, draped table, boom mic "spider", fully-draped stand. Still doesn't pass ACX noise floor. Should I go to pedestal mic on table? Might use a shorter USB cable... Anyway I sure would appreciate your comments.


Chuck

Alice4raw11162018.wav

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