Importance of DAC

theredcommando

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I have a very basic (and hope that its not a stupid) question.

On numerous threads, DAC has been mentioned. I fail to understand importance of DAC. I mean most modern MP3 players/mobiles have extremely ideal frequency response. I personally own Nokia 5800 and its frequency response is extremely linear(refer gsmarena for more details)

This is measured as anlog output obviously. So now my question is why is DAC at all necessary? What value addition is it going to have?

Can somebody please explain this objectively to me?
 
First, it must be understood that every digital audio device that outputs sound that you can hear (even if it has to be amplified first) contains a DAC --- a Digital to Analogue Converter.

Your portable media player has one. Your incredibly expensive CD player has one.

That example leads to the next point. As with many things, All DACs are not born equal.

I don't know much about audio from phones. Some are said to produce very high quality audio when used as portable music devices. I can say that my phone does not, but then, a Motorola Defy+ is less than half the price of some of the smart phones on the market. Do the phones from Sony that carry the Walkman tag live up to that in terms of sound quality? The iPhone is so hyped that it probably exists in a reality warp anyway; many people say that iPod sound quality can easily be beaten by other brands.

I had neglected the headphone socket on my phone, and a recent mention of such things here made me try it. At first, the sound seemed bright, detailed, but the bass was there too. After just a few minutes, I felt listening fatigue, and knew that, yes, I still had to take my heavy brick of a Cowon A2 on train and plane trips. No idea what the frequency range of my phone is, but anyway, frequency response is just one of the aspects of sound quality: it says what we can hear, but I don't think it says anything about how good it will be.

Almost any computer that you buy, including laptops, will have a headphone socket (and even a microphone socket). Many will even be ready to output multichannel home-theatre sound. All this on motherboard that, in total, cost less than a mid-price soundcard.

Even these built-in soundcards, which cost the manufacturers hardly anything, are vastly better than the early add-in cards (soundblaster by name and nature), and I think they are better than most people realise --- but I admit that I don't use mine.

So, yet again: all DACs are not born equal.

You might share my deep suspicion, though, about the intense marketing of hifi DACs, and the belief that it has caused in the hifi community. Doubt is a powerful marketing tool. People are buying, for instance, high-quality CD players, then they get some doubt: do I need a DAC? You can see that from the threads here. If a person already has a good CD player, then no, they probably do not need a DAC: the one they have already is good enough!

If, on the other hand, they want to get more out of a modest CD player, or they want to get hifi sound from their PC, or they have several devices with digital output, and want to get the best analogue sound from them all, with similar sound flavour, colour, whatever, or lack thereof, I'd be the first to say: Buy a DAC!

That is DACs in context, as I see it. I don't own a stand-alone DAC, although I have quite a few DACs, and I hope I'm being fair.

But... I am still deeply suspicious about high-price hifi DACs, because I am sure that marketing department thought has gone like this...

--- Whoa! We can sell something that does a fraction of what a soundcard does, for several times the price!

--- Double Whoa! In fact, we can price it at the same price as people are used to paying for any other hifi-separate device!

It's called pricing according to what the market will stand, and has nothing to do with actual value.

But can I say that no multi-lakh DAC could possibly be worth it? No, of course I can't (especially as I haven't heard them) --- but my cynicism would be a little less if it was made for the pro sound market, rather than the hifi market. That's my prejudices :)
 
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So now my question is why is DAC at all necessary? What value addition is it going to have?

Can somebody please explain this objectively to me?

Necessary? - no, definitely not (assuming your other components are decent).
Nice to have? - yes, definitely.
Does it improve the sound? - Depends on your other components.

Thanks to Thad's excellent write-up on DACs, I don't have anything to add except my personal experience. Here are two typical setups at my place.

1) Transcend MP3 Player --> Norge 1000 Amp --> MS Carnival 8 FS
2) Transcend MP3 Player --> BriteView 5005 Media Player --> Norge 1000 Amp --> MS Carnival 8 FS

To my ears, the music through setup (2) sounds a bit richer & fuller than (1). This, I think, is because the BV-5005 has a better DAC than the MP3 Player. But this is only for MP3 files. For FLACs, the difference is much narrower and barely perceptible.

I have tried an FIIO E7 DAC from a friend, and I did not perceive any difference between using the BV-5005 and the E7. When I find a reasonably priced DAC that gives a clearly superior sound than the my current setup, then I will go for it.

IMO, the price-performance relationship follows an S-curve (see image below - replace time with price). At the low end, price is low and so is performance. As you get ready to pay more, performance improves quickly - hence the steep incline of the S. Then it flattens out into the area of diminishing returns - no matter how much more money you are ready to spend, you will only get small incremental gains in performance.

scurve2.png
 
I could hear a clear difference \ improvement while using a dac replacing the dvd player. The equipments were Nakamichi RE-10 stereo amp / Quad 22L2 with Beresford Caiman DAC / Philips DVDP, another FM was also there at that time and he could also hear a big difference. It was long time back. We had tried, MP3 (128/320), FLAC and Audio CD, all were showing clear improvement while using a dac
 
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I have a very basic (and hope that its not a stupid) question.

On numerous threads, DAC has been mentioned. I fail to understand importance of DAC. I mean most modern MP3 players/mobiles have extremely ideal frequency response. I personally own Nokia 5800 and its frequency response is extremely linear(refer gsmarena for more details)

This is measured as anlog output obviously. So now my question is why is DAC at all necessary? What value addition is it going to have?

Can somebody please explain this objectively to me?

More price = better quality/sound/value is something assumed by the buyers.

And even better understood by the sellers (especially their marketing departments)


Of course there are some real differences too, but how much that contributes to measurable response in listening is disputable.
 
Well, yes, thats why stressed on the objective part.
By necessary, I mean for good quality sound. IMP DAC output and any descent output from mobile/mp3_player would not differ much on measurable parameters(my suspicion is max 10%)

I agree that with a good DAC any digital output could be converted into good analog output. But, my suspicion is, whatever provides Digital out would also be providing descent analog out.

Here is the frequency response of the Thad's phone (motorola defy)-
Motorola DEFY review: Drag and drop - GSMArena.com

Its output looks good. Though they have mentioned that after attaching the headphones, output worsened so this might be affecting the output quality.
So my next question is(apart from subjective opinions) on what actual parameters output of DAC defers from output of a mobile/mp3 player?

I cant think of any reason. Signal is a signal and there would be enough electronics already in speaker to filter out noise. Whatever data is collected on gsmarena, convinces me that analog output of any descent phone is pretty good. Are there any other params(apart from THD, noise and frequency response) that affect the sound output quality?

I suspect that its the amp that has to be blamed rather than DAC(internal or external). May be if signal is weak(like from mp3 player, there is more noise) amp cannot boost it accurately enough(teja's case). Is any data available on what characteristics an amp adds/changes to the output?
 
I have followed that S curve in my experience with PC soundcards, when I first started playing with them about ten years ago, except, unfortunately I didn't make progressive steps, but I could tell the difference from built-in to 15 sound card (but built-ins were not nearly as good in those days. I could hear the difference of the next step to a 50 card. Then I took a leap to 200 card and nearly threw away the CD player (which had an MRP of three times the cost of that sound card). That was an RME card. The next thing would have been to spend about 1,000 on a Lynx card, which was widely considered the Rolls Royce of PC sound cards at the time, and is still well-respected. Would it have been five times better? I could never afford to find out, and now never will, but I suspect I'd have found myself on the top of that S curve. Especially as I was actually unaware, at that time, of how well-respected RME was and is, in the pro/semi-pro audio world.

Guys, thanks for all the thanks: it looks like that stands to be my most appreciated post ever :D. The day I actually go out and buy a standalone DAC will probably be the day I loose all my objectivity on the subject :lol:

(a DAC/Headphone-amp is currently a possibility, but my amp and cd player are dying, so it is a very low priority)
 
There is something else that is not born equal too.

Some of the more technically minded like to know what the actual DAC chip is inside the DAC, so this is something that quite often gets discussed. However, remember that the implementation and circuitry is important too. Also, the implementation of USB interfaces can vary a lot. It seems that, with USB, it is possible to buy in the minimum electronics and plant them on the board, whereas those who wish to do better do their own software development.

I've also read that some sellers quote the specifications of the chip but that the circuitry in which they place that chip is not up that specification.

There is room for honest difference in pricing.

There are also people like NwAVGuy, who claim to have produced a DAC which performs to the highest possible specification, performs extremely well according to the his measurements as an engineer with a demand for perfection ... and sounds good, at a very reasonable price.

Well, as of yet, I only have his word for that :), but I find his blog very interesting, and hope, one day, to be able to try out one of his designs for myself. See note in brackets in previous post.
 
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@ teja. Your setup has great speakers but since you are using the Norge 1000 you will not be able to hear the nuances of a good DAC.

Nothing against Norge as I am myself an owner. I have 3 DACs. The FiiO E7, a DIY burr brown 1798 based DAC and a quad Wolfson DAC and can definitely hear differences in quality with my hd650 headphones as well as my myref amplifier. On the contrary the differences are muted when I use the Norge 1000 and the mids are mellow and not as revealing as the myref or my headphone amplifiers.

@ thad. Nice post. And I believe many forum members will be interested in the ODAC. Can't we get together for a group buy! I already have three but this one is quiet portable will be a great external portable device for the iPad or laptop.
 
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Sorry to say that I have not got answer for my question neither discussion on points that I have raised(apart from individual opinions). I wonder if anybody has followed my post at all. Some other interestinng points are discussed, though.
 
I have a very basic (and hope that its not a stupid) question.


On numerous threads, DAC has been mentioned. I fail to understand importance of DAC. I mean most modern MP3 players/mobiles have extremely ideal frequency response. I personally own Nokia 5800 and its frequency response is extremely linear(refer gsmarena for more details)

This is measured as anlog output obviously. So now my question is why is DAC at all necessary? What value addition is it going to have?

Can somebody please explain this objectively to me?


0's and 1's dont just automatically become audible sounds. We are organic creatures and our ears are analog for the most part.

DAC's were invented at the dawn of the digital age back in early 70's. Vinyl is analog, cd is digital.

To convert those 0's and 1's into analog sounds our ears can hear a DAC must convert that data and output it to a device that deals with presenting that data further.

It does not value add to anything, it's a NECESSITY.

The quality of the dac and it's implementation determines the quality / signature of sound going to an amp/preamp/active crossover.

If your dac is crap, no matter what high end equipment you connect, you'll still hear crap.
 
Though thad has answered you question fully. I will make it simple.
1. A flat frequency response even in analog is not the only thing which makes the music sound good although it is an important characteristic that the output should be akin to the source material e.g. the sansa clip+ has a flat frequency response but it doesn't sound as good as the HM801 media player. It is calculated by playing a noise signal (which consists of all frequencies) at a specific voltage and calculating the output amplitude which ideally should be a flat line fron 20 hertz to 20000 hertz.

2. The other characteristics like total harmonic distortion, inter modulation distortion, dynamic range, signal to noise ratio, cross talk etc also matter a lot which have to be taken into consideration when something like music is playing. Which definitely will be poor in your player / phone as compared to some of the best media players (Why because they have better DAC and analog amplifier circuitry).

So DAC is one of the sub entities of the over all audio chain which will improve these. Say your DAC is poor the rest of the analog circuitry will not help how high end it may be. The chain is as strong as the weakest link. In most of the well made audio chains it is the speaker or headphone which is the weakest link because of its inefficiency to produce the entire audio spectrum as a flat line. Good DACs and amplifiers score very high on the above said points.
 
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@corElement and @Thad
I surely understand what DAC is. Perhaps my thread title was not correct enough, though its clearly mentioned in the content.(I am not able to edit it now...)
I will rephrase, My question is, why DEDICATED DAC is important and its value addtion.

Which definitely will be poor in your player / phone as compared to some of the best media players (Why because they have better DAC and analog amplifier circuitry).

This generalization is funny. Any proof for this? What is the difinition of 'better DAC'? As I mentioned, all parameters of a humble mobile phone are very good, what would DAC improve?
I am certainly NOT talking about amplifier here.

Anybody here has any information about output from the amplifier? How clean that output is(values of frequency ranage, THD, dynamic range)? Can anybody post measurements?
 
Thad has already posted a link which shows what measurements are needed. here is the links. The E10 DAC costs around 7K while DAC1 Pre costs around 75K. Such performance will not be available in mobile phone costing 10K. So the generalization is correct.
Now I ask your good self to post these measurement of you mobile phone / player and compare it here. Hope that answers your query objectively.
However it would be better answered by blind testing of your phone as source compared with a laptop with dedicated DAC as one you will hear the difference if you have a good amplifier and speaker.


NwAvGuy: ODAC Released

NwAvGuy
 
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I will rephrase, My question is, why DEDICATED DAC is important and its value addtion.


To reiterate: it is better, and it adds value if it is better than the DAC you have already.

Better? You might take into account reviews, opinions of others, even engineering measurments, but, in the end, better or not is entirely your judgement, just as it is when buying any other component in your setup.

and

You cannot judge sound by looking at frequency-response graphs, as they only give a small part of the picture. Also, if they originate from the marketing departments they will be, if not doctored, at least presented (graph scale, etc) in such a way as to look as good as possible.

OFFTOPIC...

Audiodoc said:
I believe many forum members will be interested in the ODAC. Can't we get together for a group buy! I already have three but this one is quiet portable will be a great external portable device for the iPad or laptop.
Great idea. Regret that replacing my amplifier (unadventurous sticking to the current model of the same manufacturer)is going to eat up 40,000 that I don't really have, plus failing CD player, so even though the ODAC (its the combined ODAC/headphone amp that interests me) is small change by comparison, I don't think I can join in just now. Looks like Epiphany Acoustics, uk is the place to buy, as and when it goes into production
 
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I have also earlier posted very similar measurements and link for Thad's Motorola DEFY mobile phone.

Motorola DEFY review: Drag and drop - GSMArena.com

As one can see, numbers are not very bad(its not poor at all!) for mobile either. Stereo crosstalk, dynamic range seems better in custom DAC(but I am not very sure if unit of measurement is same in both cases).
Dedicated MP3 players might even excel these readings.

I think people percieve difference in audio quality not because of DAC but because of amp and speaker as both these components add their own color to the final output.
 
Now the mist seems to be clearing off!

You can see a dynamic range of 88 will not compete with 111 and the units are same decibel A weighted.

So your 64 kbps recordings may sound the same on both but if you have lossless files like FLACs a dedicated DAC will sound much better than the phone and media player when connected to the same (but good quality) amplifier and speaker.

Secondly you should use a line out cable for your player otherwise the signal will pass through the headphone amplifier circuit of your phone or media player which is not a good idea.

Also the defy does not have a flat frequency response there is a hump in the lower frequencies at around 50 dB accentuating the bass.
 
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Well, its very clear that DAC would add SOME value. My initial intent for asking this question was because somebody might point out some parameter(or some logic) that I might have missed earlier.

Subjective judgement add little value because subjective misunderstanding can be treated with training and learning. So notioin of 'better' should be verifiable and should be proven unanimously.

Even before posting this, I knew that dedicated DAC would improve final sound by some amount. But I concluded that it would be marginal in case of modern mobile/mp3 players/sound cards at least. This discussion more or less supports that notion.
For non commercial use of audio(i.e. if you are not earning your bread and butter with sound) I am ready to ignore it. Any takers?

That being said, I would still like to hear more opinions about this :)
 
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Importance of DAC is explained by few Gurus of this forum. I didn't get what else you are expecting from your initial question.

I have experienced major improvement in music quality in musical fidility V-DAC in my previous setup. DAC provided inside these mobile are dead cheap quality. To understand it, connect your headphone to a reasonably good CD player and mobile phone without much explanation you will get it right.
 
For audiophiles it is not marginal. It is only marginal if you listen to compressed recordings and use amplifier / speakers which are run of the mill ones.

If you have a good setup and try to run it using a mobile phone / media player / DVD player as a source the difference is night and day when compared to a good CD player or Computer+good DAC.
 
Purchase the Audiolab 6000A Integrated Amplifier at a special offer price.
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