High noise floor, hiss, high beep sound

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High noise floor, hiss, high beep sound

Permanent link to this post Posted by chrisauda » Tue Apr 11, 2017 1:40 am

I have been recording books for ACX ok, besides the occasional QC issues (which seem to be flagged inconsistently project-to-project even with passing ACX plug-in).

I recently submitted a sample to Deyan Audio and they wrote back:

The room tone is too loud and there is a noticeable hiss in it and every couple of lines has a beep.
It sounds like the Noise Floor is too high, the difference between the volume when you are speaking and when you are silent is not great enough. There are a number of things that could cause this but sometimes simply adjusting input gain/levels can go a long way.

I am attaching a sample, if anyone can suggest re: the beeping (which I don't have in every recording) and suggestions on the hissing and loud room tone, etc.

I am using Windows, Audacity 2.1.3, AudioTechnica AT2020 USB+. Thanks.
Attachments
Sample.mp3
High noise floor, hiss, high beep sound
(517.35 KiB) Downloaded 8 times
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Re: High noise floor, hiss, high beep sound

Permanent link to this post Posted by kozikowski » Tue Apr 11, 2017 2:30 am

Do they use ACX Technical Standards? You don't have to. ACX Noise Standards, while rough to meet are not all that strict.

Is that a Yeti microphone, by any chance?

I applied a custom filter called "YetiCurse" to the supplied clip and the beeping went away. I set the RMS (Loudness) using another custom tool and then brought the blue wave peaks back to standard with Audacity > Effect > Limiter.


Screen Shot 2017-04-10 at 19.23.37.png
Screen Shot 2017-04-10 at 19.23.37.png (41.58 KiB) Viewed 205 times


Before I ride off in all directions, was that your raw performance? No processing? We strongly recommend against laying multiple effects atop each other.

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Re: High noise floor, hiss, high beep sound

Permanent link to this post Posted by kozikowski » Tue Apr 11, 2017 2:52 am

It's also strongly recommended not to use MP3 anywhere in the production process. MP3 creates sound distortion and you can minimize it, but you can't make it go away. Export WAV (microsoft) 16-bit for your archive, production and capture files. The company may require you to submit MP3, but that should be the first time you downconvert the work WAV > MP3.

Let us know.

I'm only concerned with the technical specifications. You may still get bounced for theatrical problems. The clip you posted may be a little sharp and crisp. One of the other elves may drop in with a way to help with that.

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Re: High noise floor, hiss, high beep sound

Permanent link to this post Posted by chrisauda » Tue Apr 11, 2017 3:53 am

Koz, thanks for your reply.

The clip is not raw. I did Equalize, Normalize, Limiter, Amplify, and Normalize to meet ACX standards. I export my audacity files to mp3 only after editing final.

My mic is Audio Technica AT2020.

I thought about Deyan's feedback, adjusting the input gain. My current input gain usually generates around -25 on the Contrast test (then I edit to get to the ACX -18 to -23 range). When I increased the gain, I was peaking too much. If I lower the gain, I'm afraid the sound will get distorted with all the editing to make it louder.
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Re: High noise floor, hiss, high beep sound

Permanent link to this post Posted by kozikowski » Tue Apr 11, 2017 4:33 am

OK, stop, stop, stop.

So we both applied multiple different filters, possibly conflicting with each other.

Shoot a mono sound test and post it. Shoot it like you shoot everything else, just like normal, but export a WAV sound file before you do anything to it. I need a clean sound clip.

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

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Re: High noise floor, hiss, high beep sound

Permanent link to this post Posted by Trebor » Tue Apr 11, 2017 11:51 am

chrisauda wrote:... every couple of lines has a beep ...
ATTACHMENTS Sample.mp3 High noise floor, hiss, high beep sound

I don't know what's causing the intermittent faint beep , but you can get rid of it by using this notch-filter code in Audacity's nyquist prompt.

Code: Select all
(setf *track* (notch2 *track* 3000 50))
(notch2 *track* 4000 50)

what the code looks like when pasted into audacity's Nyquist prompt.png
what the code looks like when pasted into audacity's Nyquist prompt.png (9.41 KiB) Viewed 191 times
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Re: High noise floor, hiss, high beep sound

Permanent link to this post Posted by kozikowski » Tue Apr 11, 2017 1:54 pm

I don't know what's causing the intermittent faint beep

It's a USB microphone?

Even thousand cycle tones suggest strongly USB negotiation data leaking into the sound. It's a version of Yeti Curse and it reacts positively to that "standard" set of notches.

The custom suite is a subset of the larger suite.

(notch2
(notch2
(notch2
(notch2 *track* 4000 50)
3000 40)
2000 30)
1000 20)


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Re: High noise floor, hiss, high beep sound

Permanent link to this post Posted by kozikowski » Tue Apr 11, 2017 3:19 pm

I suspect if the tones were louder, you'd be needing the rest of the notches.

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Re: High noise floor, hiss, high beep sound

Permanent link to this post Posted by chrisauda » Wed Apr 12, 2017 3:45 am

Trebor, your Nyquist filter removed high beep on my edited clip. Thanks for sharing.

Koz, am attaching a raw .wav.

Re: changing the input level to get a bigger difference between the noise floor and speaking volume. Does anyone have any experience with this?

Thanks everyone for your help.
Attachments
Sample 2.wav
Unedited
(1.66 MiB) Downloaded 8 times
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Re: High noise floor, hiss, high beep sound

Permanent link to this post Posted by kozikowski » Wed Apr 12, 2017 6:47 pm

Does anyone have any experience with this?

Yes. The goal is to announce so your peak sound meters poke up around -6dB or so. This can mean you need to pay attention to the meters and the script at the same time. The meters can be made much larger so they're easier to see. Click and drag. The latest Audacity design has the meters changing color when you get close making them even easier to see.

Image

-6dB is usually low enough so you don't go over (0dB) on expressive phrases and it's still reasonably loud not to have background hiss noise problems. It is a juggling act.

Many people have trouble making it up that high with a USB microphone because they tend to record low volume as a design goal. That's one of the problems with cramming all the microphone bits, parts and services into one small package.

Thank you for the clip. I'll get back to it.

As we go.

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