Help...Vinyl to CD...How many MB's?

[paul]

Ouch :o
That's a little pricey for me right now. I know you're gonna tell me you get what you pay for :D

[Bernie]

Paul, not sure if this helps, but Graham's audio card is listed for under $100. at...
M-Audio

[BrunoRepublic]

Failing that, Sam Ash has it for $150 US.

[paul]

Thanks Bernie. I'll let you know I lucky I am.

[paul]

Well, good news and bad. First the bad. I got out bid on the M-Audio. I guess they are really popular and good and perhaps I'm a little cheap :oops:
The good news. Wallowing in my saddened state after seeing I was out bid, I had an epiphany. I decided to check my soundcard configuration on the computer. I had the mic box checked. So the reason I was only getting one channel is I was using the mic input before. Once I checked the line input and connected my tape deck to line in, voila :D

[Mixmachine]

This card's price apparently hasn't drop much in the last two years when I paid 150.00 at Midi-store.com. they still have it for this price.

[geo__]

I Will explain how much space is needed for 1sec.

The standard for audio cds is 16 bit 44,1Khz

This means that I take 44,100 samples per second and I encode every sample with 16 bits.

1 Byte=8 bit, so 16Bits=2 Bytes

so it's 44100X2=88200 Bytes. That is for mono.

For stereo is 88200 X 2 = 176400 Bytes

Now 1Kbyte=1024 Bytes so 176200/1024 is 172.265Kbytes

and 1Mb=1024 Kbytes so it's 0.168Mb
That's what you need for 1 second of stereo recording.

Now why 44,100 samples? There's Nyquist's theorem which says that if I sample an analog signal at twice its maximum frequency I can reconstruct it without loss.

So we assume that the maximum hearable frequency is 22,050Hz. In reality it is about 16Khz only. If you don't believe go to an acoustics labs and test your ears.

I think that the 96Khz sampling rate that some cards often is way too high and you won't find any difference in sound quality. Of course it reduces aliasing (which theoritically is 0 at Nyquist's rate, but this isn't a perfect world), but still I think is unecessary and I wouldn't be surprised if one day in the future music labels offer audio cds with these characteristices just to find a way to charge us more than we have to pay.

George

[BrunoRepublic]

Originally Posted by geo__

So we assume that the maximum hearable frequency is 22,050Hz. In reality it is about 16Khz only. If you don't believe go to an acoustics labs and test your ears.

Very true, however...

1 - the actual maximum is slightly less than half of the Nyquist frequency. Open up almost any commercial CD in a wave editor with spectral view, and you'll find that there is almost nothing above 20k.

2 - Most people can only hear up to about 17KHz (myself included), however there are a few with "golden ears" who can hear up to 24KHz or even higher.

3 - Although most of us cannot hear any signals above 20KHz, these signals do alter our perception of how the audible ones sound.

The 16/44.1 standard was based on what was considered state-of-the-art in 1983. There's no reason why we can't do better than that today. It doesn't really have anything to do with killing off the CD, as the buying public has already demonstrated considerable indifference to the format in favour of lossy audio codecs (and even those with average hearing could tell the difference if they were to compare on a decent system).