VO-BB - 20 YEARS OLD!

Steve Knight · Posted: Sat May 12, 2012 9:23 am Post subject: Sample rates question...

OK here's an email I got from a client the other day....

"One of our Go to V.O. guys suggest recording at: 160k mono or 320k stereo for best results.
What are your thoughts on that? His stuff just tends to be much louder than most."

#1. I've always been uncer the impression that 44.1 was the industry standard,..at least it has been for folks I've done work for..

2. I use AA 1.5, which has a top sample rate of 192k...

Can anyone out there make any sense of this...or is my client mis-informed?

Bish · Posted: Sat May 12, 2012 10:23 am Post subject:

The beams have been crossed!!! There are two specifications being jumbled here...

You are perfectly correct that 44.1kHz is the standard sampling rate for CD quality audio. It had become the de-facto standard for high-quality audio except in some video production situations where 48kHz is preferred. In situations where quality is not critical (such as telephony) lower sampling rates can, and are used. The sampling rate is the number of times per second that you "look" at the waveform and... er, sample it. Most applications will allow for sampling rates higher than 48k (96k, 192k etc.). In this encoding, we would also select the bit depth... am I recording at 16 or 24-bit? This gives us our raw audio (wav or aiff). Stick to your 44.1 unless specifically asked to deliver a 48k raw file.

Now, to encode as an MP3 files, we have to decide on the amount of data compression we use (and hence the quality of the compressed files compared with the original). This is the 160kbps/320kbps being quoted at you. Personally, I record all my stuff at 320kbps mono, but this is too high for some, and they will require 160kbps mono (or 320kbps stereo). Others will want 256kbps... some sites will re-compress down to 128kbps mono. Generally speaking, the higher the mp3 bit-rate, the closer it will be to the original files, with fewer compression artifacts and losses

The suggestion of 160 mono or 320 stereo is fairly standard. The comment about volume is bogus... it has nothing to do with the sampling rate or encoding quality, but everything to do with the original VO's settings on recording level, normalization and stuff like that... adjustments during or after recording, not during encoding.

Others will probably make it clearer than I have Smile

Cheers
Peter
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heyguido · Posted: Sat May 12, 2012 11:05 am Post subject:

Bish is on the mark.

CD quality (44.1) is fine for most projects, unless film is involved.

And less compression when converting to mp3? Less squashed = less trashed.

As for your client's perception of higher volume? Again Bish is correct. Higher volume has nothing to do with recording bitrate or mp3 file compression.
It's simply a function of input levels during the original recording.

Everything else is file conversion.
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Steve Knight · Posted: Sat May 12, 2012 11:45 am Post subject:

OK,...I checked my MP3 commpression settings and they were indeed too high..something like 18kbps 1600hz...I don't remember
the highest quality setting AA has is 128kbps which works out to a 5.5:1 ratio...this is a technical area I have very little knowlege of, so bear with me..

As far as the loudness issue goes, I usually send my tracks with only a little compression, or none at all by request,..if they want it loud then I use the "Barricade" hard limiter plug

Bill Campbell · DC Joined: 09 Mar 2007 Posts: 621

You can record in AA 1.5 in stereo and save as 320kbps.
It has nothing to do with loudness, though.

Use the hard limiter in AA if you want perceived loudness. It works well and sounds fairly clean. Set the peak to -1 and add 3,4,5 however many db you want to increase.
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Lance Blair · M&M Joined: 03 Jun 2007 Posts: 2281 Location: Atlanta

Related to this, should one have 128kbps 44.1kHz mono files on one's website/promotional links for quicker upload, or is it worth it to have higher quality mp3s with slower (how much slower?) downloading? Thanks in advance for any and all responses!
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Lance Blair · M&M Joined: 03 Jun 2007 Posts: 2281 Location: Atlanta

I did a test that partly answered my question: 320kbps stereo (VBS) sounds so much better!

http://lanceblair.net/sharing/EasternBank128Mono.mp3
http://lanceblair.net/sharing/EasternBank320Stereo.mp3

I just recorded the voice quickly 48/32 mono in AA3 with lip smacks and all left intentionally to hear it. Wink

Sennheiser Mk4>Focusrite ISAOne>MAudio Fast Track Ultra (going INSERT in to bypass the preamps).
Then added the stereo music track, mixed them and put the AA3 multiband compressor and hardwall limiter in the "Broadcast" setting on the Master out. Then I converted them to a 128/44.1 Mono and a 320/44.1 Stereo files.

But people still want the smaller files for downloading and sharing, right?
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Frank F · Posted: Mon May 14, 2012 10:16 am Post subject:

Yes, 320 kbps ,mp3 does sound "better" than the usual 128; the reason is simple - it is less compressed and therefore loses less in conversion. The 320 baud rate in actual size is very close to that of a wave file.

A 128 kbps .mp3 file with input at 44. kHz stereo is considered to be near CD quality audibly. This misnomer is why the higher baud rate is often requested by production houses.

Mp3 is a lossy format. Specifically lows and highs are acoustically thrown out during conversion with higher compression rates (not audible compression, but data compression).

In Adobe Audition, record at 48k, convert your file to stereo, then save at the higher .mp3 baud rate. The result is a two-track mono file with less data compression.

Frank F
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Jeffrey Kafer · Posted: Mon May 14, 2012 11:07 am Post subject:

I think your 320 sample sounds better only because it's in stereo. Do a more apples-to-apples comparison with both of them in mono at different compression rates. Less of a difference, and unnoticeable to most human ears.

Heck, ISDN, which is the "standard" is compressing down to, what, 64 kbps?
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Jacob Ekstroem · Posted: Mon May 14, 2012 2:16 pm Post subject:

Frank F · Posted: Mon May 14, 2012 4:58 pm Post subject:

Not everyone has broadband. I am stuck with dial-up due to my location at present. And, it sucks.

Frank F
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Lance Blair · M&M Joined: 03 Jun 2007 Posts: 2281 Location: Atlanta

Jeff's definitely right in that it sounds better because it's in stereo - the music sounds better and the voice sits better in the mix. So there is something to be recommended about going with that.

So, following Jeff's suggestion, I recorded this quick clip 48/32 mono and saved as a .wav and then converted it to 128kbps 44.1 kHz mono with a Constant Bit Rate and as a mono mp3 that is 150-240 Variable Bit Rate. It's not a huge difference, but definitely I hear a difference in the high end on words like "sources" but I'm sure most people will not be able to tell the difference. However, the people who hire based on listening to countless demos probably can hear the difference. Mr. Everyman can't hear the difference, sure, but we're not trying to impress him, no?

http://lanceblair.net/sharing/SolarTest128CBRMono.mp3

http://lanceblair.net/sharing/SolarTest150-240VBRMono.mp3
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bransom · DC Joined: 06 Nov 2008 Posts: 650 Location: St. Louis, MO

I record everything at 48k which keeps the video guys happy. (Avid systems used to refuse to import anything less than 48k so it became a sort of habit.) Then I down sample as necessary. Usually deliver mp3's at 192k.
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D Voice · Been Here Awhile Joined: 26 Jun 2010 Posts: 232

Frank F · Posted: Wed May 16, 2012 8:59 pm Post subject:

Douglas, yes. I just inadvertently sent a file at recorded at 48k (and converted to .mp3) which had been requested at 44.1kHz to a client. Lucky for me, they were OK with it. Although I have sent them the 44,1k file also.

The up record/down conversion goes back to my "old school" ways with analog tape. Back in the day we recorded at 15 ips (inches per second) and mastered at 7.5 ips, the reason being there was less audible tape hiss at the higher speed of tape.

Frank F
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