HiFi CD player vs DAC
January 24, 2011 9:57 AM   Subscribe

Audiophile questions: HiFi CD player vs DAC. What benefit is there to a CD player compared to just getting a quality digital/analog converter? What exactly is a quality DAC? Help me avoid audiophile snake oil!

Background: I am looking into a hi-fi setup with amp and 2 speakers. It will be for music, especially classical and electronic, and not for home theater. Budget is flexibly around 2.5 - 3k euro.

It seems to me that if you get an external Digital/Analog converter, then all CD players produce the same quality sound. Drives already must have read error correction to read data disc, and read buffers fix jitter. Neither require special "hi-fi" technology. As long as there is digital output, cd players should all produce the same bits.

So why do hi-fi CD players cost upwards of 500€? Does the price then reflect the DAC inside? And just to take a step back, is a Digital/Analog converter a component that you ought to devote a good 20% of your budget to, or is it more like paying hundreds for connectors?

I'm wary of both the nonsense that permeates the audiophile world, but also of creating a weak link in a new setup.
posted by cotterpin to Technology (15 answers total) 1 user marked this as a favorite
I'm sure somebody else could explain it much better than I will, but here you go:

It's all about the quality of the source. A hi-fi CD player could produce the sound you're looking for, IF the data on the CD isn't corrupted/amplified/trash. Many CDs produced now have a terrible quality of actual data on them, so if you want music that is worthy of an expensive setup then you need to find the correct sources, there is a reason why a 24-bit 2 hour concert runs upwards of 2GB in size.

I hope that helps somewhat, at least in extra info
posted by zombieApoc at 10:06 AM on January 24, 2011

As long as there is digital output, cd players should all produce the same bits.

Not really. What does the CD player do if it encounters a scratch, and there is a missing byte or two? They will use various schemes to fill the holes, such as repeating samples. An audiophile CD player sometimes has a fault light, that lets you know when a bad sample has been patched. Unless you keep your CDs very clean, that light will always be on.

If you read your CDs into the computer, the software should retry several times until it gets the data, or else warn you that it's missing.

I use a firewire Digidesign Mbox2 Pro for audio playback, from CDs that are downloaded to disk. It's noticeably better than any other CD playback that I can afford.
posted by StickyCarpet at 10:07 AM on January 24, 2011

Like StickyCarpet said, the difference is how the CD players handles scratches. The formats used on music CDs has fewer error correction bits than that data CDs, so they are even more prone to data loss than data CDs, which are themselves far from perfect. The €500 CD players will have fancy CDs stabilization, multiple lasers, and fancy algorithms that integrate the view of all these lasers to guess what data might have been under the scratch.

If you take good care of your CDs, or if you immediately rip them to FLAC immediately after buying them, none of this fanciness is needed.
posted by gmarceau at 10:26 AM on January 24, 2011

Quality of components matter, too. A CD player that is poorly built from cheap plastic is going to vibrate more, or track less well, etc. than one built well from good-quality materials.
posted by rabbitrabbit at 11:16 AM on January 24, 2011

Yes, a buffer eliminates jitter, and pretty much any CD player is going to have decent error correction because they all use the same chips from the same manufacturers. Some higher-end mechanisms will have less vibration and thus use the error correction less, but this is not likely to be audible on most discs because vibration is rarely a problem anyway.

Before 1-bit DACs it was possible that an external DAC would be better than an internal one because putting more money into the product allows you to manufacture them to tighter tolerances (or to hand-calibrate them after manufacturing). However, 1-bit (noise-shaping) DACs are cheap and sound essentially perfect, so that's basically that.

That's not to say you should buy a $10 Wal-Mart CD player, but any decent name brand CD player costing $50 or more will be very difficult to tell from an "audiophile" CD player in blind listening tests.

One thing that might be worth looking for is a player that will play SACDs. These "super audio" discs have two layers, one CD-compatible and one that provides a higher-quality signal. These will be more expensive than regular CD players (and you will typically get a DVD player in the bargain) as are the discs, but they do provide an actual benefit. Many SACDs also have a surround mix in addition to the stereo mix. A similar format is DVD-A (DVD-Audio). Many DVD players support a number of these audio formats in addition to video playback.

If that's too rich for your blood, at least make sure the player supports HDCD. This is a format that is compatible with standard CDs. Many CD releases have HDCD encoding, and it is reasonably common in affordable name-brand players, and it does offer some benefit.
posted by kindall at 11:50 AM on January 24, 2011

A CD player combines a CD transport and a DAC into one package. Most people, even audiophiles, will get their best deal with a CD player. High quality CD players to please audiophiles abound. Most CD players will have some form of digital output allowing you to use a separate DAC. A transport just plays the CD and spits the digital output to a separate DAC. Thus, you can use a CD player like a transport if you have a separate DAC. Getting a steady stream of jitterless data from the transport improves the overall sound so quality matters in that aspect. Translating the digital output into an accurate analog signal remains a challenge, one that you will notice if you have high resolution equipment in the rest of the chain (amps, speakers, etc.). Clocking is an issue as well. Some DACs take the clock signal from the transport others will reclock, which is a very good thing. More info can be found here and here.

Why a separate DAC? Especially if you listen to classical there is now music available at much higher resolution than standard CDs. Also, many people now like to stream their music from a computer or other source to their stereo. It arrives digitally and some form of DAC is needed to get an analog signal. Many streaming options include a DAC but by using your own you can perhaps improve the sound. You can also add a DAC to a CD player to improve its performance if the new DAC is significantly better than that in the CD player.
posted by caddis at 11:53 AM on January 24, 2011

pretty much any CD player is going to have decent error correction because they all use the same chips from the same manufacturers.

They don't do error correction, they do hole filling. And that is impossible to to correctly, whatever you mean by decently I don't know.
posted by StickyCarpet at 11:59 AM on January 24, 2011

One thing that might be worth looking for is a player that will play SACDs.

Even if you never plan to play an SACD, this is good advice. Rule of thumb is that your signal processing should be designed to handle input at least twice the bandwidth of what you will actually be using.
posted by StickyCarpet at 12:04 PM on January 24, 2011

cotterpin, IMO your skepticism is well-placed. A $20 generic multiformat drive will generate bit-perfect burst-mode/single-pass rips at speeds of 20x or more, which to me is an excellent sign that CD error correction* is plenty robust, and that "high-end" CD transports are largely flummery. The Red Book standard is over thirty years old -- the days of needing subtle magic to get the correct bits off a compact disc are long over.

Of course, that doesn't mean that all CD players actually do output the same bitstream from the same CD -- only that there's no good technical reason why they shouldn't.

*StickyCarpet, the CD standard has included true error correction since day one.
posted by Lazlo at 12:38 PM on January 24, 2011

caddis, the separate DAC is to replace the CD player entirely. I have music in flac format on my HDD. I'm considering ripping cds to a lossless format as needed, and going macbook->DAC->amp and spending the difference on the amplifier.
posted by cotterpin at 1:14 PM on January 24, 2011

Don't forget, room treatments and speaker positioning will impact the sound more than anything.

Ripping to lossless (I used APE back in the day but now I'm almost all FLAC, with the occasional Apple Lossless) and then device -> DAC -> amp is the way to go. Really, you just want the bits to get to the amp. Whether you've got a dedicated player of some sort or a full fledged computer or even HTPC, if the bits are all there, then the next stop is a quality DAC, then on to amplification. You can do so much more with this compared to a CD player and your FLACs will never get scratched and you never have to look for a CD, just click.
posted by Brian Puccio at 1:35 PM on January 24, 2011 [1 favorite]

I have music in flac format on my HDD. I'm considering ripping cds to a lossless format as needed, and going macbook->DAC->amp and spending the difference on the amplifier.

Very cool. I am streaming iTunes to my stereo using airtunes and an iPod Touch. iTunes doesn't play FLAC files though which is a pain considering how many I have. I could perhaps use different software for the streaming, but I am not sure what just yet, and am not sure that such alternative can be controlled with an iPod.

The DAC in the Airport Express is so so but it does have digital out so I too am in the market for a good DAC. Given the limitations of wfi I am hoping to find one that in addition to accurate analog conversion has a large buffer and also re-clocks the digital signal. Bits are bits, but when you are transforming them into analog signals when those bits arrive is almost as important as what they say.

If you are going directly into the stereo then a USB DAC is a good choice. I hear great things about this Musical Fidelity one, which you can probably get used for about 60% of the new street price. This HRT is also supposed to be good, but I am basing that only on one review I saw.
posted by caddis at 3:14 PM on January 24, 2011

I don't think CD players are going to give you anything that hard drive's and DACs won't in terms perceivable sound quality. If you have to money to buy hi-fi CD players, cool, have fun.

I have a CD player merely for the convenience of playing discs straight away.

BUT once I got a Squeezebox, playing discs seems REALLY tedious now. I get much more enjoyment out of accessing an entire collection instantly (a la iPod).
posted by Ultra Laser at 3:51 PM on January 24, 2011

Spend the money you were going to spend on a DAC on professional room treatment instead, and you'll have a much nicer sound.
posted by Jairus at 4:41 PM on January 24, 2011 [1 favorite]

Caddis, the nice thing about lossless is you can transcode a million times and won't lose anything. An overnight batch conversion to apple lossless would be a one time thing.
posted by Brian Puccio at 7:11 PM on January 24, 2011

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