Audacity Forum

I can't do it, either. [Record] Blammo! Crash City.

It doesn't give you additional headroom. It gives you better footroom and you can move your show further down without hitting the mud. Keeping in mind that broadcast uses 48000/16 and their "natural" sound level is -20, not -12 like DV or higher. Zero VU tone at -20 (it's marked on our DVRs) and the average peak show levels around -12 or -10.

No broadcast show ever had headroom or noise problems that I know of.

But, you're right. It's broken and there is 0.000% chance of it being fixed. 1.3.x is out now and it will coexist with 1.2.x (just don't run them both at the same time). 1.4.x is in the wings.

Koz

Just wanted to make sure it wasn't a problem with my unit specifically. However it does record 44/24 on a widows xp machine.
So you are saying it won't be fixed for 1.2, or at all? Would it be possible to record 44/24 when 1.4 comes out?

<<<So you are saying it won't be fixed for 1.2, or at all?>>>

Not in 1.2.x. Not unless you personally want to fix it. The code is available. The Audacity developers are hell-bent on getting the documentation and program version 1.4.x out the door as the stable version of the 1.3.x beta software. We're using at least two version old software depending on how you count. Are you still using Windows 98?

What is your fascination with 44100? You know that was the compromise scan rate that they used 30 years ago so they could push audio CDs out the door without violating too many physical rules. Using a graceful Nyquist transform, you can't get an audio CD frequency response much beyond 17 KHz. FM broadcast is 15KHz. 48000 will take you out to 18.5KHz. with a few tricks to make it to 20 KHz., the generally acknowledged upper end of human hearing.

Audio CDs are the only ones still using 44.1. DAT, DVD-PCM, Broadcast, DV, all dropped 44.1 like a hot rock in favor of 48. 16 bit stereo audio is generally considered to have a dynamic range of high 80s or better, I think 96 is the theoretical limit. What are you doing that needs better than 20 dB headroom and 65 dB noise floor? That's enough to have silent speakers in a quiet room and still be able to knock over a vase with a drum beat. Most analog audio amplifiers won't go beyond that. I did a live vocal performance at 48K/16 and my microphone amplifier and room noise killed me long before I hit the digital limits.

iTunes will accept 48 KHz/16 just fine and convert to excellent quality 256-AAC (custom rates available out to 320) for your iPod and back out to 44.1 for recording audio CDs. The audio CD will be the lowest quality thing in that whole chain.

Koz

Koz,

I hope you don't mind, but I have taken the liberty of posting part of your last reply here to the thread I started a while ago in the "Audio Processing" forum on "Any recommendations for compression quality settings" http://audacityteam.org/forum/viewtopic.php?f=28&t=2581- as it sheds some interesting light on that thread.

WC

We'll see if I get any arguments over my numbers. I regularly get into it with other engineers about actual implementation of some of that technology. I picked AAC because that compression is generally regarded as twice as good as MP3, another million year old technology. So again, depending on how you count, 256 AAC is the rough equivalent of 512 MP3--essentially (but not actually) uncompressed.

CD Audio is the same problem. With very aggressive Nyquist work, expensive filters, adding noise and dithering signals, you can force CD audio, kicking and screaming, out to 22 KHz frequency response, but do you really think you want to be listening to music while it's doing that?

Koz

kozikowski wrote:We'll see if I get any arguments over my numbers. I regularly get into it with other engineers about actual implementation of some of that technology

I shan't argue with your numbers koz
You stated that the theoretical numbers are more impressive than real world numbers, which is quite true. CD manufacturers may claim 20 Hz to 20 kHz, but if you work out the mathematics with a 44.1 kHz sample rate it gets very "iffy" above 16 or 17 kHz.

kozikowski wrote: I picked AAC because that compression is generally regarded as twice as good as MP3, another million year old technology. So again, depending on how you count, 256 AAC is the rough equivalent of 512 MP3

I will argue with that though
Not all mp3 encoders are equal and often there is a trade off between sound quality and processing speed. To my ear, LAME produces the best sounding mp3's at given bit rates compared to other mp3 encoders (160 kbps VBR and above), but that's hardly surprising since LAME is the only that I know of that is still being actively developed. There's been quite a bit of discussion about this on the Hydrogen Audio forum, and their most recent listening test indicate that there is very little to choose between AAC and LAME mp3 (or Ogg Vorbis).

Interestingly there was a post from one of the main LAME developers, dated 2004, where he claimed that AAC had the potential for higher quality than mp3 is capable of, however it seems that while the LAME developers have squeezed some excellent performance out of the mp3 format, AAC has still not achieved significantly better results than are possible with mp3.

Another subjective personal note about this - most of the AAC recordings that I've heard (iPod) have been rather poor quality. (I've also heard some really appalling quality mp3's as well), which I think indicates that it's not just a matter of the format. Simply using a high definition format does not mean that it will sound good.

(Apologies for being off topic)

Oh, no. Not thread wander!

MPEG 1, Audio Layer III only became an ISO standard in 1990, but I think the design goes back to 1988. Yes, because of the way lossy compressors work, you can get better and better at it by throwing (newer) technology and being careful how you work. It's an effort and time problem. Dual Pass makes everybody work better at the expense of time.

It wouldn't surprise me that you could perform all the tricks with lame and come out with a result that's the equivalent of a simple, quick pass through AAC. Are you willing to go to all that effort every time given that top grade AAC is available with a couple of key clicks in iTunes setup.

There is one other point that people miss. Destructive compressors pretty much without exception only work their best when presented with perfect uncompressed shows. That's why my scenario works so well. There's only one compression step and one sub-sampling.

It doesn't make any difference whether you're talking about video or audio. If you present a compressor with damaged, compressed, or marginal performances, you have doomed your show to substandard quality--worse than you think--and it doesn't matter which coder or how many passes you use.

44.1 is considered a barely adequate delivery format and nobody thinks you should be doing production in it. That's just asking for trouble.

Koz

kozikowski wrote:
That's why my scenario works so well. There's only one compression step and one sub-sampling.

Koz

Koz,

but if you record/edit in Audacity and then use LAME to create a good MP3 - and then import this MP3 direct into iTunes/iPod - then surely there is also only one compression sub-sampling step in that process too?

WC

kozikowski wrote:Oh, no. Not thread wander!

Koz

And that's exactly why I pointed you to my other thread ........

WC

Ok, ok. I'm going, I'm going.

Koz