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Is there a best connection to use?

post #1 of 8
Thread Starter 

I am kind of new to the world of digital audio and I was wondering. My PC has outputs for usb, Coax and Optical and the dac I am getting has inputs for all 3. Is one better is some way than the others? Just from a newb's perspective optical sounds the best, but to be honest I have no idea. I noticed when shopping for a dac that some of them only support the higher sample rates for the coax and optical inputs, so I am thinking those may be the way to go?

 Do they make high quality connectors for all of those or, being as how we are talking about a digital signal, would that make little real difference?.


Edited by HPiper - 3/24/13 at 1:34am
post #2 of 8

Sort of surprised nobody replied yet. 

 

What you should consider is picking your DAC based on what you want it to do for you, then pick the interface connection and cable to accomplish that goal.  As you noticed, some DACs have limitations associated with different interface types.  

 

There are always higher quality connectors, but there's not much to be gained from them.  Once a solid connection is made, or in the case of optical, a connection with strong optical transfer, there's no improving it.  Connector quality comes into play if you plan to do a lot of connect/disconnect cycles, otherwise, not much of a factor.  There are two common types of optical connector:

 

 

My experience is that the 1/8" mini version (left) can be a bit fragile, but even though I've had one break between the shaft and the handle, it still worked fine.  

 

I know it's been debated, but since what you're doing is transferring data, once that's done in a way that transmits data error-free, there's no audible difference between cables.  There may be certain performance advantages for a specific type of connection, but it's related to design of the DAC more than the cable or connector.

 

One last thought, again highly debated: there's little evidence to support an audible advantage of high sampling rates, especially over 96KHz.  There is a similar lack of hard evidence to support that converting original CDs to high rate/high depth files does anything positive.  

 

The one possible advantage to an optical connection to your PC is that it isolates the DAC electrically from the PC, and PCs have notoriously noisy power supplies. If the DAC is to feed an audio system, that can be a concern, and the isolation of a non-conductive data path is a very nice plus.

post #3 of 8
Thread Starter 

Thanks for that information, I think I will go with the optical then, your view makes perfect sense to me. I also found your comment that higher sampling rates do not make a significant difference in the sound interesting. There are certainly a lot of people that think it does, not saying you are wrong it is just interesting. Many of the music sites I  visit to buy music have a large number of the albums available at much higher sampling rates than 96khz. Granted they usually cost the same regardless but they are catering to those who do think it makes a difference. If you know of any discussions on this subject I'd appreciate it if you could point me in that direction. I find this kind of stuff real fascinating.
 

post #4 of 8
Quote:
Originally Posted by HPiper View Post

Thanks for that information, I think I will go with the optical then, your view makes perfect sense to me. I also found your comment that higher sampling rates do not make a significant difference in the sound interesting. There are certainly a lot of people that think it does, not saying you are wrong it is just interesting. Many of the music sites I  visit to buy music have a large number of the albums available at much higher sampling rates than 96khz. Granted they usually cost the same regardless but they are catering to those who do think it makes a difference. If you know of any discussions on this subject I'd appreciate it if you could point me in that direction. I find this kind of stuff real fascinating.
 

The high-rate argument usually goes like this: Original material captured at high rates/depths is better and has more detail.  Possibly, but those files are very few in number, and not usually much that's familiar.

 

Originals resampled to a higher rate are improved because the filter requirements are less damaging.  That's nice, but all DACs already over-sample for that very reason.  There's no creating more information by up-sampling, it's the rough equivalent of connecting the dots.  And, in what good ABX testing has been done, there's no evidence people can hear the difference.  

 

There is some logic to capturing original audio higher than 44.1KHz, and there is logic to 24 bits during capture/recording and post.  But there's no logic to releasing it that way.  If there's any point to high rate high depth at all, it would be in material that was recorded that way and maintained all the way through post to release, which isn't what's typically going on.  I recently asked one of the sellers of high-rate files about how they were created in an attempt to establish value for me.  I specifically asked if the files were simply conversions of existing release masters, or if there was anything special done.  In the case of analog originals, I asked if they digitized the masters at a high native rate, or if they were the masters already in storage, just up-sampled.  Their response was nothing more than a disclaimer that they only re-sold what was provided them by record companies, and had no information about how they were done.  That's not an answer, that's not helpful, and gives me no reason to buy.

 

I think you'll get a nice warm feeling at first listening at high rates, but at some point you'll forget and play a standard rate file and enjoy it just as well, then the game's up.

 

The above is my opinion of course, and it's highly likely others will have their differing opinions.

post #5 of 8

For the quality you get, it really depends on what the DAC's doing, really implementation-specific.  However, I think with many audiophile-oriented DACs with multiple inputs, the USB input is treated as an afterthought or add-on module by the designer, so maybe it's worse.  A lot of times they don't even bother with something that can do higher than 16-bit, 48 kHz, as maybe you've noticed.

 

As mentioned above, seeing as computer power supplies can be pretty noisy, using optical is a fine idea so you're not connecting the devices electrically, maybe avoiding a potential ground loop, or whatever else.  That's what I would go with.

 

But more likely than not, it's probably just splitting hairs, not any real appreciable difference in the sound quality.

 

 

As for high-res for home playback, you'll find plenty of discussions on audio forums.  Just scroll down the list in this subforum.  I'm not going to guarantee the quality of discourse and factual correctness of statements made in arguments therein, though.  Personally I think jaddie summed it up very well, and that's about where I would leave it too.

post #6 of 8

It really depends on the implementation, but USB (2.0) can transfer more channels / higher formats and if implemented properly will not depend on the host's clock resulting in very low jitter (audibility is again a matter of debate, usually not an audible problem though...)

 

I'd rate FireWire equal or even better than USB, and PCI Express best.


Edited by xnor - 3/24/13 at 4:47pm
post #7 of 8
Quote:
Originally Posted by xnor View Post

It really depends on the implementation, but USB (2.0) can transfer more channels / higher formats and if implemented properly will not depend on the host's clock resulting in very low jitter (audibility is again a matter of debate, usually not an audible problem though...)

 

I'd rate FireWire equal or even better than USB, and PCI Express best.

xnor raises some good points re: USB 2.0 speed and the jitter issue, though I think it's small.  I've tried all three methods, FireWire 800 is the fastest, but not much of that speed is required for audio of any style, even 8 channels of 96/24 doesn't tax firewire or USB 2.  USB 3.0 is actually faster, but not prevalent yet.  But a practical note, USB 2.0 is perhaps the easiest to deal with because it's best supported on more devices and OSs.

 

Toslink (optical) is kind of a dumb interface, in that it's limited to audio only (USB 2 and FireWire do other things), and is a one way pipe.  There can be bandwidth limitations in poor optical cables, which can cause an increase in jitter, which is the objection people have to optical.  Short high quality optical cables should cause no problems though. 

post #8 of 8

pretty much everything is sold today is "USB 2.0" - the real distinction for audio is USB Audio Class 2.0 drivers that can do async transfer with data rate timed by the DAC clock

 

but enough work has been put into the existing clock recovery from Isochronus source that the resulting jitter really isn't likely audible


Edited by jcx - 3/25/13 at 1:49pm
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