question about audio DAC's

[daviethek]

Basic question.

I noticed several relatively cheap DVD players boast good audio DAC's. ( 24/196 ) . Why don't cheap CD players ( like your basic Best Buy multi disc jobs) have the same Audio DAC's. The DAC chips don't seem to be cost prohibitive since they are in cheap DVD players so it doesn't seem to be a question of cost. Also, if DAC chips are relatively inexpensive, why are external DAC devices so expensive?Just wondering. Thanks, dk

[Cincy2]

The DAC chip is only part of the equation. The power supply, shielding, chassis etc. add cost in proportion to the quality of the sound produced. Separates (DAC and CD transport) have double the cost for these same common components. Having said that, there are relatively affordable separates available that produce exceptional sound. They cannot however be found in the big box audio stores. Try the online stores at Music Direct and Audio Advisor for a variety of almost "budget" systems that sound fantastic. Also, go to stereophile.com and browse the back issues. They publish reviews of affordable equipment as well as the stratospherically priced stuff. The Absolute Sound, another audiophile magazine had an issue earlier this year that featured recommended systems at all price points.

Bottom line: You can beat the brand names in price and quality by doing some research.

Good hunting
Cincy2

[hermanv]

I think 24/96 is the default audio mode for movies, so all DVD players will have 24/96 D to A converters.

That's nice, most of them still sound awful. As Cincy2 said the DAC might be the least of the questions.

1. A DAC specified for 24 bit 96KHz conversion may only have 16 bit accuracy. Actually this is a very difficult test so maybe they don't do even that well.
2. Power supply noise is a big issue.
3. It turns out that the analog circuits are tougher to get right than the digital ones. The better analog solutions using first rate capacitors and such probably wouldn't even fit in the modern DVD chassis.
4. Most people decode the audio stream in their receiver so the question becomes moot.

Don't believe specs, they are written by people trying to sell you something, believe your ears.


...Why don't cheap CD players ( like your basic Best Buy multi disc jobs) have the same Audio DAC's. Redbook CD are all recorded at 16/44.1 so you can't just add a24/96 DAC you also need to upsample. Many years have been invested in making 16/44.1 sound better with some very good results, adding a faster DAC without the support it needs to shine, might actually make things worse.

[Sir Terrence the Terrible]

I think 24/96 is the default audio mode for movies, so all DVD players will have 24/96 D to A converters.

Actually the default audio for movies is 24/48khz. The reason 24/96khz chipsets are used is for DVD-A, two channel DAD's, and the ability to upcovert most sources to 24/96khz using standard(those algorythms marketed by other companies), or proprietory(algorythms designed inhouse) upsampling techniques.




That's nice, most of them still sound awful. As Cincy2 said the DAC might be the least of the questions.

Actually if properly implemented they sound quite good. But they(because cheap high quality chipsets are pretty cheap in large lots) are often mated with components of lesser quality, are often to blame for poor sound.


1. A DAC specified for 24 bit 96KHz conversion may only have 16 bit accuracy. Actually this is a very difficult test so maybe they don't do even that well.

This USED to be a problem amoung DAC's, but not anymore. Most DAC's nowadays come pretty close to their rated bit rate. What usually kills the sound quality in components that use these chips is the quality of parts downstage of the DAC's



2. Power supply noise is a big issue.
3. It turns out that the analog circuits are tougher to get right than the digital ones. The better analog solutions using first rate capacitors and such probably wouldn't even fit in the modern DVD chassis.
4. Most people decode the audio stream in their receiver so the question becomes moot.

I agree with you here.


Redbook CD are all recorded at 16/44.1 so you can't just add a24/96 DAC you also need to upsample. Many years have been invested in making 16/44.1 sound better with some very good results, adding a faster DAC without the support it needs to shine, might actually make things worse.

Actually I don't think they even market those kinds of DAC's for CD playback. I think it is more towards DVD-A, upsampling DD and Dts, and the ability to use filters that are alot less steep. If CD was the main reason for the use of 24/96khz, the it would make more sense to market a 24/88.2khz DAC.

[hermanv]

Hi Sir Terrence;

When I said 24/96 was a standard rate for movies I should have said for DVD, I believe all are recorded at 24/96.

I don't design or buy components for DVD payers so I can only guess....

I see players selling for $60. Based on my experience, that means they bought them for $30 and based on further experienece that means they built them for $15.

The transports cost about $5-6 in huge volumes, the pretty painted and lettered box is going to run you $2-5, leaving a whole $4 to $8 for all the rest of the electronics. Subtract another $1 or 2 for the fancy display (yes I know it sounds high but they are) and you can not afford a first class D to A.

I agree they are better than they were, but true 24 bit performance is still limited to a select few devices. 24 bits is a largest to smallest step range of 144dB or 0.0000059%. I've never even used a piece of test equipment that good.

[Sir Terrence the Terrible]

Hi Sir Terrence;

When I said 24/96 was a standard rate for movies I should have said for DVD, I believe all are recorded at 24/96.

The standard bit rate for DVD's is 24/48khz, not 24/96khz. The sample rate of the elements that make up the soundtrack have sample and bit rates all over the map.



I agree they are better than they were, but true 24 bit performance is still limited to a select few devices. 24 bits is a largest to smallest step range of 144dB or 0.0000059%. I've never even used a piece of test equipment that good.

The object is not to create a source with a dynamic range of 144db. It is more of having the dynamic range of the chipset being able to handle all volume levels, and not be a hinderance to the source.

[JohnMichael]

Basic question.

I noticed several relatively cheap DVD players boast good audio DAC's. ( 24/196 ) . Why don't cheap CD players ( like your basic Best Buy multi disc jobs) have the same Audio DAC's. The DAC chips don't seem to be cost prohibitive since they are in cheap DVD players so it doesn't seem to be a question of cost. Also, if DAC chips are relatively inexpensive, why are external DAC devices so expensive?Just wondering. Thanks, dk

The Marantz 5001 cd player is the lowest cost cd palyer I have seen with the 24/196 DAC. It is available for $300.00 from Audio Advisor and Music Direct.