Tweaking Audio CD Specification

[apakhira]

Hi
just like the specifications of VCD SVCD were tweaked to get higher quality and XVCD and XSVCD were born, can we do the same to audio CDs to get higher sample rate, etc?
And i also want to know if there's an app which can author Audio CDs outside the Audio CD Redbook Standard.

[mats.hogberg]

The specifications aren't tweaked, they are ignored. Neither XVCD nor XSVCD is a standard, it's just another way of saying "non standard". Depending on the good will of the hardware used to play (S)VCD this may work or not.
I'd guess the same goes for audio CD's, but I doubt you'll find audio CD harware as forgiving as video CD players...

/Mats

[Heavensent]

unless your source is better, how would you create a
better qulity audio cd ?
you cant create qulity if its not there.

there are just a few ways you can do it,

*if the source is dvd (its 48000) - you may be able to get away with a 48000 wav.

*if the source is a digital camera.

what you CAN do is make the wav sound better in YOUR ears,
up the bases or treble, and clean the source noise a bit.
thats about it.

[apakhira]

Yes, my source is a 48 khz. DVD audio(AC3) file.I have converted it into a 48 khz. wave file.But how will i make the audio cd with 48 khz. sample rate?

[RabidDog]

burn it, and see if it works. Like newton, Experiment.

[apakhira]

But softwares like NERO Burning ROM don't let you burn audio cds out of specification.They just re-encode the file to 44.1 khz.I have NERO Express 5.5.1.0.

[OldeSquide]

Yes, my source is a 48 khz. DVD audio(AC3) file.I have converted it into a 48 khz. wave file.But how will i make the audio cd with 48 khz. sample rate?

Don't get so hung-up on sample rate. Yes, 44.1 is a stoopid, arbitrary number (that 'they' thought would make it more difficult to 'copy' - back when CD Audio was first established...) But it still holds way more info than our ears can distinguish when used properly.
Consider that you're coming from AC3, which has already thrown away data - worrying about re-sample to 44.1 is not likely going to downgrade it any. If, however, it sounds like shit in AC3, then expect the same effluent regardless of the sample rate you end with.
Better off getting the source files and mastering so that they sound as intended, and then 44.1 will be plenty good enough.
Oh... and if you want CD audio, it will be 44.1

Too OldeSquide

[vitualis]

Considering that an audio CD has the data in uncompressed PCM, if you put a 48 kHz audio onto it, a CD player won't know and just play it at 44.1 kHz sampling rate. That is, everything will sound lower and slower.

Regards.

[apakhira]

For your information, OldeSquid, if you have good ears, you will notice a slight difference between an Analog audio tape and a normal CD.The same track played in an analog tape has more detail and higher frequency response than a CD.

[Cornucopia]

For your information, OldeSquid, if you have good ears, you will notice a slight difference between an Analog audio tape and a normal CD.The same track played in an analog tape has more detail and higher frequency response than a CD.

Unless he has access to 1" or 2" Multitrack reels, there is NO WAY any analog tape would sound better than a CD.

Just start by looking at simple numbers:
Cassette: 40-16,000Hz, ~60db SNR, .1% wow/flutter
CD: 20-20,000Hz, 96db SNR, wow/flutter imperceptible

Audiophiles talk about analog sounding better than CD, but when they do, they're refering to pristine LP's and Studio master reels, not cassettes.

****

If the original poster is starting with compressed AC3, uncompressing and SampleRate converting won't undo the damage already done.
You want better sound? Find a SACD, DVD-Audio, or studio master reel and convert to CD with High Quality SRC and Dither.
One other option if your DVDplayer and Surround Decoder supports it, Make a AC3 or DTS CD. Do a google search for info on how to set this up.

Scott

[Cornucopia]

Here's the link:

http://www.kellyindustries.com/diy_5_1.html

Be forewarned, files must also be in 44100Hz not 48!

Have fun!
Scott

[apakhira]

Cornucopia, u were right.I did a mistake by saying that analog audio tapes were good. i was trying to tell about the LPs.A question has cropped in my mind-
increasing which will increase the quality of an audio file?-
1)the no. of bits?
2)the sample rate?

Thanx

[Cornucopia]

A question has cropped in my mind-
increasing which will increase the quality of an audio file?-
1)the no. of bits?
2)the sample rate?

Thanx

Both...

<<Below assumes Linear PCM>>

16bit PCM audio is ~96db Signal-to-Noise/Dynamic Range
20bit is 120db,
24bit is 144db (rule of thumb is 6db added for every 1bit)

144 is actually better than just about EVERY analog-to-digital converter is capable of, including the best professional mastering studio converters.

8 more bits= 1 1/2 x file size

This makes most difference with reverb, transparency, detail.

44.1kHz audio has Frequency response range from
0Hz(really 20Hz)--22.05kHz (really 20kHz)
48kHz range is 20-24kHz
88.2kHz range is 20-44kHz
96kHz range is 20-48kHz
176.4kHz range is 20-88kHz
192kHz range is 20-96kHz (basically, like Nyquist theorem says, response= 1/2 sample rate, minus any LowPass filtering requirements)

20-22kHz is said to be the upper limit of human hearing. This is an AVERAGE (some can hear more, many will hear less--old folks and people with loudspeaker hearing damage ). Also, hearing isn't the same as perceiving. The higher rates are said to provide better stereo/binaural/surround imaging, are more "open" and "scintillating". Having heard some A/B trials, I would agree.

Cost?
88/96 is 2 x filesize of 44/48
176/192 is 2 x filesize of 88/96, or 4 x filesize of 44/48

Whether it's worth it is your own decision.

For me, it depends on the program material.

HTH,
Scott

[Cornucopia]

If you want better audio, you must start with better audio master. Just like with video better DVD/(S)(X)VCD quality comes from better video masters--DV, BetacamSP, Digibeta, Uncompressed, HD, etc.

If you want an audio CD that will be compatible with most players, you're stuck with standard audio quality, unless you want to spend the time and $$$ to get your material mastered at a qualified HDCD studio. Then you would have ~20bit audio as opposed to 16bit, and it would still be compatible with standard players, although the full quality wouldn't be realized unless you had a HDCD-capable player.

Other routes to go would be higher rez PCM audio muxed with Pix slideshow on DVD-Video disc (not playable on std Audio CD players), or true DVD-Audio (not playable on std AudioCD or std DVD-Video players).

At this time, home authoring/burning of SACD's isn't possible.

The AC3-CD or DTS-CD link that I gave is still an option, but the benefit is more because of multichannel capability, not so much increased resolution.

Scott