Why ? DAC digital audio converters - AVS Forum
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post #1 of 22 Old 02-13-2013, 04:01 AM - Thread Starter
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I always thought a digital sound would be superior to analog sounds. Isn't that why we have optical out's from our devices. If so, why do we use DAC's because it converts dig to analog which I thought (i may be wrong) was a de-grade. please help me understand.

This is NOT for a PC - I am thinking of Hi Fi systems at home
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post #2 of 22 Old 02-13-2013, 04:41 AM
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Quote:
Originally Posted by darrelsilva View Post

I always thought a digital sound would be superior to analog sounds. Isn't that why we have optical out's from our devices. If so, why do we use DAC's because it converts dig to analog which I thought (i may be wrong) was a de-grade. please help me understand.

This is NOT for a PC - I am thinking of Hi Fi systems at home

A basic explanation, analog waveforms are needed to drive the amps and speakers. Some still prefer the sound of a high quality turntable or reel to reel tape over digital, as they represent a more accurate or full resolution of the original analog waveform, plus no need for the extra circuitry for converting. But at the expense of higher noise floor and other types of distortion.

If someone could explain in more detail, it would be interesting.
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post #3 of 22 Old 02-13-2013, 06:22 AM
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Sound waves are analog. Digital representations must be converted to analog in order to produce sound we can hear.
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post #4 of 22 Old 02-13-2013, 08:13 AM
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Quote:
Originally Posted by darrelsilva View Post

I always thought a digital sound would be superior to analog sounds. Isn't that why we have optical out's from our devices. If so, why do we use DAC's because it converts dig to analog which I thought (i may be wrong) was a de-grade. please help me understand.

This is NOT for a PC - I am thinking of Hi Fi systems at home

We really don't have any truly digital Hi Fi speakers.

A truly digital speaker would convert signals in the digital domain directly into sound waves without any conversion to analog.

An example of this would be a speaker with 16 different diaphragms whose size ranged over an approximate 32,000:1 range in binary steps (doubling in size starting from very small). They would then be driven by the corresponding bit in the 16 bit musical waveform. These diaphragms would have to respond with excellent precision 44,100 times per second. Just a little problem actually making such a thing! ;-)

The closest we get is speakers with, you guessed it, DACs inside.
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post #5 of 22 Old 02-13-2013, 08:22 AM
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Originally Posted by arnyk View Post

An example of this would be a speaker with 16 different diaphragms whose size ranged over an approximate 32,000:1 range in binary steps (doubling in size starting from very small). They would then be driven by the corresponding bit in the 16 bit musical waveform. These diaphragms would have to respond with excellent precision 44,100 times per second. Just a little problem actually making such a thing! ;-)

OK, that's 16 bits of frequency information, what about dynamics? How is that encoded?
I know, I ask you a lot of questions, sorry, but you seem to be a fountain of information.

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post #6 of 22 Old 02-13-2013, 08:53 AM
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I always thought a digital sound would be superior to analog sounds.
There's really no such thing as digital sound. What you are talking about is digital storage of sound, which really is better than analog storage. But that digital information has to be converted to an analog signal in order to drive speakers. That's what a DAC is for.
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This is NOT for a PC - I am thinking of Hi Fi systems at home
Doesn't matter, the principle is the same. Most audio/video systems have multiple DACs: in your computer's sound card, your CD player (or DVD or Blu-Ray player), your TV, your receiver. Whenever you hear sound (or see video) that was stored in digital form, one (or more) of those DACs is doing the necessary conversion work.

If you're asking why you'd need a separate, outboard DAC, the answer is you don't. It would be redundant.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #7 of 22 Old 02-13-2013, 12:10 PM
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Originally Posted by JD in NJ View Post

OK, that's 16 bits of frequency information, what about dynamics? How is that encoded?
I know, I ask you a lot of questions, sorry, but you seem to be a fountain of information.

16 bits of dynamic information. frequency limit is set by the sampling frequency. CD 44.1KHz gives you a practical extension out to 20KHz (allowing for a very steep filter to keep sounds above 1/2 the sampling frequency out of the system so you don't get weird artifacts.

So around 100 dB of dynamic range potential and in essence zero to 20KHz frequency range . . .
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post #8 of 22 Old 02-13-2013, 12:16 PM
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Thank you for that. Between your post and a bit of additional reading I did I believe I now have a much better understanding of the A/D and D/A conversion algorithms.

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post #9 of 22 Old 02-13-2013, 12:21 PM - Thread Starter
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I still find ot hard to understand, perhaps lack of knowledge. Why are we very particular when we shop to buy devices (for example a DVD PLAYER and an AMP) that have toslink outputs ans toslink inputs.
If analog is the key, why wouldnt we just get the old DVD players and amps that have left and right banana type audio cables only.
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post #10 of 22 Old 02-13-2013, 12:38 PM
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Quote:
Originally Posted by JD in NJ View Post

Quote:
Originally Posted by arnyk View Post

An example of this would be a speaker with 16 different diaphragms whose size ranged over an approximate 32,000:1 range in binary steps (doubling in size starting from very small). They would then be driven by the corresponding bit in the 16 bit musical waveform. These diaphragms would have to respond with excellent precision 44,100 times per second. Just a little problem actually making such a thing! ;-)

OK, that's 16 bits of frequency information, what about dynamics?

The dynamics are in the 16 bits.

16 bits is sufficient to encode about 96 dB worth of obvious different loudnesses, and in addition sounds that are smaller then the smallest bit can be encoded below the residual noise level. If you do everything right the perceived effect of 110-120 dB can be encoded in 16 bits.

My hypothetical digital speaker would then have at least 96 dB dynamic range and would ideally sound like it had 110-120 dB dynamic range.
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post #11 of 22 Old 02-13-2013, 01:16 PM
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Quote:
Originally Posted by darrelsilva View Post

I still find ot hard to understand, perhaps lack of knowledge. Why are we very particular when we shop to buy devices (for example a DVD PLAYER and an AMP) that have toslink outputs ans toslink inputs.
Do you understand that Toslink is a digital transport medium? If you have a CDP/DVDP/BRP playing a CD, then Toslink is transporting a serial digital signal of about 1.4Mbits/sec.
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Originally Posted by darrelsilva View Post

If analog is the key, why wouldnt we just get the old DVD players and amps that have left and right banana type audio cables only.
The signal encoded on the disc is digital, and it must be converted to analog at some point. You can do it via a DAC inside the player, or send it via digital link (Toslink, coax, HDMI) to some other device.

If you send it digitally to some devices such as an AVR where the AVR can then process that signal in a DSP to provide EQ, room correction etc. If you sent it analog, then it has to be re-digitised before processing.
It's my experience that external DACs offer little to no improvement over the internal DACs in most players and PCs.
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post #12 of 22 Old 02-13-2013, 01:27 PM
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Hi Darrel,
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Originally Posted by darrelsilva View Post

. . . If analog is the key, why wouldnt we just get the old DVD players and amps that have left and right banana type audio cables only.
Analog really isn't the "key", it is simply a necessary step: A step that some of us prefer to to as late in the audio chain as we can.

My philosophy is to try to keep everything digital for as long as I can. That typically means that the digital-to-analog converter is directly before the power amplifier. Music comes off the storage digitally, across the network, into the AVR. The AVR can then do the room-correction and volume digitally within its DSP and, when all processing is done, the music is converted to analog in order to drive the power-amp and speakers.

Digital processing is very precise, while analog processing is less so. There is also so much more you can do digitally. But eventually, the music needs to become analog.
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post #13 of 22 Old 02-13-2013, 01:32 PM
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I still find ot hard to understand, perhaps lack of knowledge. Why are we very particular when we shop to buy devices (for example a DVD PLAYER and an AMP) that have toslink outputs ans toslink inputs.
If analog is the key, why wouldnt we just get the old DVD players and amps that have left and right banana type audio cables only.
Well, you could use analog connections, and the sound quality would probably be equivalent.

But modern receivers offer some processing features that can only happen with a digital signal. If you send them an analog signal, they must convert that signal back into digital to do that processing, and then convert it back to analog again to drive the speakers. All this conversion and re-conversion doesn't really do any harm, but it adds unnecessary steps. It makes more sense to keep the signal digital until that processing is done.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #14 of 22 Old 02-13-2013, 02:25 PM
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As I read it, this is what is being asked:
Quote:
Originally Posted by darrelsilva View Post

why do we use DAC's

I assume you are asking if adding an external third-party DAC will improve the sound quality compared to simply using the analog output of your current CD / DVD / Blu-ray player. Is this correct? If so, the answer is most likely No. Of all the things you could upgrade, a DAC is at the very bottom of the list.

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post #15 of 22 Old 02-13-2013, 02:44 PM
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. . . Of all the things you could upgrade, a DAC is at the very bottom of the list.
Right alongside the cables. wink.gif
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post #16 of 22 Old 02-13-2013, 02:45 PM
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Quote:
Originally Posted by darrelsilva View Post

Why are we very particular when we shop to buy devices (for example a DVD PLAYER and an AMP) that have toslink outputs ans toslink inputs.
If analog is the key, why wouldnt we just get the old DVD players and amps that have left and right banana type audio cables only.
If you want discrete multichannel audio, then left and right banana type audio cables aren't enough. Toslink digital can carry encoded DD 5.1 and DTS soundtracks. Analog transmission would require one cable for each channel. Besides, that merely changes the place where the DAC is done. The vast majority of media is digital and has to be converted to analog somewhere along the way. As others have already explained, it makes sense to do it later in the process.
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post #17 of 22 Old 02-13-2013, 04:21 PM - Thread Starter
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Thank you all- It has helped me. I heard crisp sound at a friends place and he said it was because of the DAC fitted. I now feel a DAC is not a requirement if you have already have good digital systems which anyway will by the machine itself do the the conversion before it goes to speakers.


Cheers
Darrel
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post #18 of 22 Old 02-13-2013, 05:38 PM
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I heard crisp sound at a friends place and he said it was because of the DAC fitted.
Lots of people believe that a DAC can make a real difference, but when you put them to the test it seems they can't really tell one from another. Best not to bring this up with your friend, however. He's happy with his system. Just let him be.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #19 of 22 Old 03-18-2013, 05:47 PM
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[quote name="MarkHotchkiss"




url="/t/1457987/why-dac-digital-audio-converters#post_22961542"]
Right alongside the cables. wink.gif[/quote]
Sorry to disagree..when I added my DAC with upgraded power supply using hi-end straight wire crescendo interconnects,a straight wire silver-link digital cable all using upgraded power cables by pangea..my sound quality was as close to heaven as never before..major,major sound improvement.. And that's using parasound halo amps and anthem prer-pro..with paradigm studio 100 speakers!
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post #20 of 22 Old 03-18-2013, 05:53 PM
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Sorry to disagree..when I added my DAC with upgraded power supply using hi-end straight wire crescendo interconnects,a straight wire silver-link digital cable all using upgraded power cables by pangea..my sound quality was as close to heaven as never before..major,major sound improvement.. And that's using parasound halo amps and anthem prer-pro..with paradigm studio 100 speakers!
Sure, but if we switched them back without your knowledge, you'd never notice the difference.

If you can't explain how it works, you can't say it doesn't.—The High-End Creed

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post #21 of 22 Old 03-18-2013, 07:05 PM
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Hi Esh,
Quote:
Originally Posted by esh516 View Post

Sorry to disagree..when I added my DAC with upgraded power supply using hi-end straight wire crescendo interconnects,a straight wire silver-link digital cable all using upgraded power cables by pangea..my sound quality was as close to heaven as never before..major,major sound improvement.. And that's using parasound halo amps and anthem prer-pro..with paradigm studio 100 speakers!
OK, I won't argue with that.

But if you really want better sound, I have a bridge I can sell you. Just owning it will improve your sound-system 1000%. And it won't cost that much more than all of those wires. PM me.
esh516 likes this.
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post #22 of 22 Old 03-19-2013, 03:16 PM
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I know that bridge you're talking about. I tried it in my system once. The midrange was sooo beautiful, I cried.

Too bad my budget wouldn't let me keep it.

For every new thing I learn, I forget two things I used to know.
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