Someone hit a very sesitive topic..... my 2 cents again for those contemplating audio compression. Plus a little understanding towards 192 vs 224Kbps+.
192Kbps employs the joint stereo encoding method, not independent bandwidth for each channel like 224, 256 and 320Kbps (like a cd player or even cassette tape record). I have one song in particular that changes phase 180 degrees left from right sources, kinda like a fancy flange, and with any bitrate lower than 224 (non-joint stereo) the phasing effect puts the song in a completely 'swishy-under water' sound, worse than a low bitrate internet stream (I use this for evaluating encoders, a 90's pop song). True there's not many songs like that around.... however it can be avoided. Bitrates below 224, have a large 'centre' or mono storage track as I understand reserved where everything common between left and right is stored. Two tiny tracks with limited bandwidth are then left for the subtle stereo differences between left and right. If there's to much stereo activity like a phase effect, it pushes the encoder to use only its limited stereo' difference' tracks, hence it simply runs out of space to make it sound like a standard 192 file and fails to encode anywhere near cd quality, I've even found this to happen in Fraunhofer's engine.
I've taken note of any station or software I've had to do work with in the sense of what are they doing, most use 256Kbps Layer-II. Understandably you get better sound at lower rates on MP3, however, unless your codec allows to specify indepedent stereo at 192, you'll may soon find a favourite song one day that doesn't sound favourite once it's been encoded joint. Other audio compression schemes that employ mpeg such as Video CD's and DVD's without dolby also only allow 224kbps - 320Kbps to keep a decent stereo image.
These days with radio going digital around the world, I can not see how programme directors are ever going to get away with using lower than 256Kbps Layer-III, as DAB uses something cronic like 112Kbps Layer-II and that's in stereo.... kinda like how the wolf sounded on Sky, some Internet streams can sound better. DAB also talks heaps about 32KHz sample rate, use that with already mp3'ed or mp2'ed files, and you have about as much crispness to your high frequencies as a potatoe chip being eaten with a pillow covering your mouth. About 12-13KHz wide. They say it's 15KHz wide, most codecs drop dead at 14KHz at 32000 sample, or are replacing the high hat with a squished snare sound.
Drives with a 3 yr waranty and uncompressed files should last?, people do DV cam video work these days on home computers requiring 50 times more head wear. I've done that much wear editing uncomrpessed files on two western digital drives at home it should equate to a few years or more of on-air playback of PCM files.
When you hear a cd played on-air through analogue or high-end digital audio processors, there's something about how 'clean' and open it sounds that simply leaves everyone else on the dial sounding what a lot of people now deam to be a bad term, 'digital'. They all sound squished and not just their volume, but the quality of the audio compression. According to RCS, there are a few now getting in to the market of PCM uncompressed audio for pre-DAB delivery and simply because it's an easy way to strive in a Californian market that all sounds 'digital'. I would say drives these days are getting pretty cheap for the extra storage.. and listener fatigue is the worse turn off.
Just my 2 cents of innovation vs followers.
Cheers,
Gavin
----- Original Message -----From: Richard PhelpsTo: LPFM_Radio@...Sent: Monday, November 17, 2003 11:41 AMSubject: Re: [LPFM] Poll results for LPFM_RadioEd you mad bugger!?!?
Why such a high setting for mp3? 192kbps is the same as uncompressed
wave in terms of kbps - anything above like 320kbps is wasting space
on your drive my friend.. Not to mention radio is prone to
interference - moreso LPFM. It's a highly debatable subject in terms
of quality vs coverage.
My 'On Air' files are 192kbps/44.1/16bit - and the quality is good. I
have backups of every song as full wave, and these backups were made
and recorded to CD prior to mp3 conversion for airplay. That way, I
have a high quality backup standing by if my harddrive decides to
pack its bags. It hasnt happened yet, and according to my CPU
monitor, I dont have to worry until August 2008 before my machine
exits the computing world. Y'know - just.. yeah, anyway..
Im gonna put a compression test on the net, once thats up, I will put
a link up through the messageboard here, and conduct your own
experiments.
All the best mate - hope them transmitters aint giving you too much
hard timez..
If TLC Radio are lurking (and reading) - I'm curious about your
settings! Mono something I know.. but just what??
R.
> Perhaps the question should be more about the compression used, not
> the file format.
>
> Anyway, the compression I use is MP3, 44.1 kHz, Stereo, 320 kbps
CBR.
>
> > perfer uncomrpessed wave here, if mp3, real stereo not joint
stereo 224kbps and up.
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