Back to basics - Getting music out of your computer

[darrenwm]

Hi, I'm new here and have a grasp on computer audio, but am looking to become more knowledgeable on things too. Below is me thinking aloud, and asking a few questions...

 

In short, I have my music on a Windows XP Pro laptop and play it through the DAC of my active speakers - AVI ADM9.

 

FIRST STEPS

 

I started by using a cheap £15 USB>Toslink adaptor like this http://www.maplin.co.uk/module.aspx?ModuleNo=34128&doy=search

 

It sounded fine but I later tested it and by plugging it into a DAC with a display and it showed that the incoming signal was 16/48, which said to me that Windows was resampling the audio. I am aware of the Kmixer and hoped that by using Foobar2000 with ASIO4ALL I'd have avoided it, but obviously my setup wasn't correct.

 

QUESTIONS - PART 1

If I were to buy a more fancy USB/Toslink thing, like the M Audio Transit, would it come with the necessary software/drives to allow a perfect 16/44 output?

http://www.millennium-music.co.uk/home/products.pl?ProductCode=MMTRANSIT&mode=detail2

Would I be restricted to using certain playback software - e.g. Foobar?

Could something like this play back 24/96 from a Windows laptop into my DAC?

 

CURRENT SOURCES

 

Mainly for the want of better interfaces I moved onto using an Airport Express, and now a Squeezebox Duet.

 

I have tested these using my crude method and am please to see the DAC was seeing 16/44 incoming to the DAC so assume my files are remaining unmolested. Sadly these devices do not support anything above 16/44. It's okay for now, but I'll have to move on in the future.

 

QUESTIONS - PART 2

 

When getting music out of the computer using IP protocols can I assume that things such as Kmixer then become irrelevant?

How can one get 24/96 and upwards out of the computer intact using network streamers?

 

FUTURE SOURCES

 

Having enjoyed my spell with computer audio so far I expect I'll play with more sources in the future and have questions to make sure I understand things fully and make the right purchases.

 

QUESTIONS - PART 3

 

USB DACs - Is USB limited to 16/44? Most USB DACs I've seen are only 16/44?

 

Firewire DACs - Do these support much higher sample rates - i.e. upto 24/192? Even straight out of a Windows laptop? Would I need special playback software?

 

If I could get 24/192 from a Windows laptop to a Firewire DAC, could this DAC potentially pass through 24/192 straight out of the optical output and into my active speakers which contain a DAC and a Toslink input?

 

If I had a Mac Book would I simply connect an optical cable straight from the MacBook to the speakers and be able to play 24/192 in iTunes without fussing around?

 

 

Sorry for the long post.

 

Thanks in advance.

 

[The Computer Audiophile]

Hi darrenwm - Thanks a lot for the very detailed post. It's a little long but no worries, this is a laid back site. At least it's well thought out and you know what you're talking about :-)

 

The M-Audio transit sure looks like it supports 24/96 audio but I don't know enough about the unit to be 100% sure. something tells me that the unit is far too inexpensive to support 24/96 from USB. It certainly is not a 24/96 DAC so that would bring the price down, but I'm skeptical. I hope I'm wrong and this unit does fully support 24/96. this would be a very nice way to get high resolution from you PC. As far as bit perfect goes you may have to experiment on your own. It is a combination of the software and hardware as you found out and I don't know of anyone using this component :-(

 

I can vouch that the Duet is bit perfect. I tested it in my system a few weeks ago. KMixer is irrelevant using an IP stream just as you suggest. The pro audio world has used IP / Ethernet streams for years, but high-end audio is pretty far behind. To get 24/96 via IP you have to use something like the Logitech Transporter.

 

USB DACs are not limited to 16/44.1. There are a few manufacturers who make 24/96 capable USB DACs for example Benchmark, Wavelength, and Empirical Audio have native (no driver required) 24/96 USB DACs. These are limited right now because of cost and design expertise.

 

A good FireWire DAC like the Weiss Minerva that I reviewed a couple weeks ago will support up to 24/192 straight out of a Mac or PC. It's a very good DAC! Traditionally FW has had more jitter, but a proper implementation and the right FW chip can come very close to the best DACs using any interface in my opinion. Daniel Weiss uses a very good FW chip and has implemented it in the Minerva extremely well.

 

It is possible to use FW to Optical. I use the Weiss Minerva a little bit to do FW to AES and it passed the music bit perfect. If your active speakers contain an analog input and they don't convert the analog to digital and back to analog, then you can just use a FW DAC for 24/192 into your speakers via analog.

 

A MacBook will only output up to 24/96 via the optical mini-toslink port. The Apple documentation all says it will support 24/192, but nobody at Apple has been able to show me how to enable this. I've tried several times with Apple. If anyone feels like calling Apple to have them walk you through this and get full 24/192 output that would be fabulous.

 

Thanks again for all the good questions. I'm sure you're not the only one wanting this information. You're just the only one who would ask! Let's keep the discussion going if you have more questions or ideas or just want to chat about this stuff.

 

[darrenwm]

Thank you for the response.

 

Are products with full 24/192 more expensive to produce, or do you think manufacturers are keeping prices high to differentiate 24/96-only products and to keep some exclusivity to 24/192?

 

My speakers have an analogue RCA input straight to the built-in analogue pre-amp, so using an external DAC is certainly possible.

 

Are toslink and coaxial capable of carrying 24/192 anyway? Or will one always need to use USB/Firewire to a DAC, and RCA analogue interconnects therein?

 

Where do you see the future going in terms of connectivity for digital audio sources?

 

I think I have a firm grasp on this from a domestic/consumer perspective, but the pro audio equipment is completely new to me, but I'm very intrigued.

 

From reading around this forum I am seeing mentions of I2S, a cable that contains clocking information. Could it be possible in future that one simply connects their computer to a DAC using only this cable? If this is possible from this connection type it would be fantastic to connect it from a little Mac into a future version of AVIs active speakers, if they continue to evolve.

 

I sold my AVI ADM9 this evening and will be buying the AVI ADM9.1 as soon as possible, so could perhaps experiment more as they have an additional input.

 

Regards,

 

Darren

 

[The Computer Audiophile]

Hey Darren - I really can't answer why manufacturer support 24/96 and not 24/192 on some products. I know USB has limitations without drivers and 24/96 seems to be the max anyone is going right now. I have no idea why Apple's optical output is not gong to 24/192 when it clearly could and should.

 

Toslink and coax are fully capable of supporting 24/192 audio.

 

Your question about the future of digital audio connectivity is a good one. In my opinion the consumer demand is increasing for higher resolutions such as 24/176.4 and 24/192. Even if there is little material available right now at those resolutions people still want to be ready for the future. Consumers also want a bit perfect interface and don't want to count on an OS or hack to get it. So that leaves us with an Ethernet interface. I believe in the run Ethernet interfaces will become very popular in consumer audio.

I would also be interested in an I2S interface but there are virtually no computer cards that support this. Steve Nugent at Empirical Audio has some mods that create an I2S interface on the Benchmark DACs, but you need another product to interface with the Benchmark then. A laptop with an I2S interface would be absolutely awesome right now.

 

Speaking of ADM9.1s, mine are on the way right now. I will have a review as soon as soon as I spend some serious time with them.