CD drives

**RedGTiVR6** · 09-21-2006, 11:43 AM

I know that there are the basic drives available out there.

The Panasonics, the Pioneers, the TEAKs, the LiteOns, etc.

However, I can't find any frequency information on any of these units.

Anyone know of any other cd players out there that they can recommend? I'm not looking for the cheapest thing out there btw!

**Jahntassa** · 09-21-2006, 07:55 PM

Okay, you got me confused.. what 'frequency information' are you looking for?

**RedGTiVR6** · 09-21-2006, 09:44 PM

responses

I'm guessing that most of these drives can't go up to 20k.

**seanshine** · 09-21-2006, 10:06 PM

Were you thinking of just taking the audio signal straight off the back of the drive? The dacs on consumer level computer drives......well,just plain out suck,lol.
I'm thinking you can get much better response from just letting the ide bus do it's job and transfer that signal to your cpu,then to to the sound card.

**RedGTiVR6** · 09-21-2006, 10:11 PM

no, not straight off of the drive.

If the signal isn't there in the first place, letting the computer do it's thing won't do anything.

**seanshine** · 09-21-2006, 10:40 PM

Ahhhh,I see where you're going here.....The reason you're not finding any frequency response specs on these drives is that they simply transfer what the laser is reading,i.e.,zero's and one's,and then it's processed by the cpu to more of the same to the sound card.
Just think of the drive as a pit and land reader,and having other hardware and software interpret the meaning of what that drive has read......that's where you're going to get the response numbers you're looking for is from how well it's processed and of course the quality of the hardware doing it.

**Jahntassa** · 09-22-2006, 12:51 AM

Yeah, that's why I was confused. Unless you're using the Audio output on the back of the drive (or headphone jack on the front, if it has one) the audio processing is done in either software or hardware. It's played digitally, I believe, straight to the soundcard, which then does the D/A conversion.

You'd really need to do research on how CD Audio works in newer systems, just to confirm that it does go digital via the IDE bus down through to the soundcard, maybe getting processing added on by whatever player you're using.

**RedGTiVR6** · 09-22-2006, 07:28 AM

Originally Posted by seanshine

Ahhhh,I see where you're going here.....The reason you're not finding any frequency response specs on these drives is that they simply transfer what the laser is reading,i.e.,zero's and one's,and then it's processed by the cpu to more of the same to the sound card.
Just think of the drive as a pit and land reader,and having other hardware and software interpret the meaning of what that drive has read......that's where you're going to get the response numbers you're looking for is from how well it's processed and of course the quality of the hardware doing it.

I have a hard time believing that you can't improve upon the quality of the drive....

**Jahntassa** · 09-22-2006, 11:58 AM

What quality do you want?

The way this stuff works nowadays is the drive reads the disc, and sends that digital data to the system to do with it what it needs. The only 'quality' standard nowadays is the speed at which it can do that.

**ruzzmon** · 09-24-2006, 06:08 PM

Just wanted to add to what the previous posters have said:

CD Audio is stored digitally in 16 bits and sampled at a rate of 44.1KHz. When converting to digital data, you need to 'sample' the input audio at a rate more than twice the highest frequency to ensure that you can recreate the original audio signal, which is part of where this 44.1KHz originates from. The 16 bits indicates how precise the digital version of the original analog (audio) signal is.

I think, when you said the drives can't go to 20k, you are referring to 20KHz, which would be the typical max audio range? The problem with making this comparison is that the sampling rate (44.1KHz) is not compareable directly to the audio frequency response - the typical bottleneck is the DAC (digital analog converter), aka your sound card. Look for 24 bit, 48KHz sampling rates or better. The higher the bit rate, the less the noise in the signal, so the higher the SNR. The higher frequency sampling rate, the more likely all frequencies were captured, including those that we can't hear but still may have some effect.

You can use other data formats and store much better audio, ie DAT audio can go upto 24 bits. Also, if you use the CD as a data storage device, you could store files that are encoded at higher bit rates and sampled at higher frequencies, it would just take more space on the disc itself.

Hope that clarifies some things and makes sense why there is no need to 'improve the quality of the drive' other than increasing the maximum storage (ie go to dvd). I'm pretty sure about most of this, but maybe others know more and can shed even more light on the technical details.