Monday, December 13, 2010

HiFi ... from a computer

The biggest dis-service to music fidelity in the last twenty years has been the development of the all conquering iPod, or virtually any other .mp3 player and nasty, cheap earbuds.

It's a pity because the digital domain holds the key to the finest musical playback. True, some players can handle more accurate codecs such as .flac and .ogg, but the norm means people don't know how real music sounds through nice yet not necessarily very expensive equipment.

Anyway, I have been playing with digital reproduction from my computer to my hifi, producing quality at the very least comparable to CD, and often very much better.

D-Link DNS-323
All of my music is now stored - mostly in lossless format - on my home network using a Network Attached Storage - NAS - device, in my case a D-Link DNS-323 with 2x1Tb in a RAID1 configuration. I'll deal with how to run a NAS device and how to prepare music files in another article.

The device is used to serve music to my laptop via WiFi. So far I've found WiFi to be perfectly adequate to serve audio files. It may be better to use a wired network connection if you intend to use video files.

Media Monkey
Currently, I am using Media Monkey Gold to handle my music files. It seems to sort and organise thousands of files well and it can also handle my PodCasts fairly efficiently. The main problem with MM is that it doesn't handle Internet Radio very well. In fact although it can handle IR streams it has no functionality to organise or store IR stations.
Media Monkey audio settings
MM can be set up to output digital audio data in a fairly flexible way. At the moment I am experimenting with two means of exporting digital data.

USB soundcard/S-PDIF output and
direct USB output from laptop
Firstly, direct from a USB port into the DacMagic which shows up as a soundcard when it's connected via a USB cable. I am also using a Turtle Beach Audio  Advantage USB soundcard to stream data to the DacMagic using S-PDIF via a toslink cable, basically optical fibre.

Rear of DacMagic
The back of the DacMagic shows the interconnects - from top to bottom - power / USB input / toslink S-PDIF input / CD S-PDIF input / RCA line out to amplifier.

I am also trying to get this laptop to output S-PDIF directly. I understand it's possible to do this by tapping the audio output of the S-Video connection. I have a cable adapter which should be able to do this, but despite being able to configure the laptop to produce an S-PDIF stream - it shows in the windows sound configuration complete with working sound level graphic I haven't managed to find out where it comes out of the computer, to use a technical term ...

Options I have which work consist of the following:

Media Monkey digital output : ASIO and waveOUT. I think the ASIO output codec is the superior, but waveOUT handles gapless playback. I haven't found a means of delivering gapless through ASIO. I'm not certain it's even possible. Anyway, the difference between ASIO and waveOUT is miniscule, if it even exists, so currently I'm sticking with waveOUT.

Output device : I currently have the choice of two. Direct USB output to the DacMagic or S-PDIF via the Turtle Beach soundcard. Direct output gives a sampling rate of 44.1kbps, identical to a CD. Using S-PDIF the output rises to 48kbps. I'm not certain if this is a true rate or whether the Turtle Beach upsamples from 44.1kbps to 48kbps. These rates are, as I understand it, the maximum which can be achieved via a USB port, hence my interest in direct S-PDIF. The DacMagic should be able to handle up to 96kbps, but it's feasible to double even that for near perfect reproduction.

Optical output on USB
To be honest, it is very difficult to discern any difference whichever combination of codecs and devices are used up to the point of the DacMagic. Far greater differences result by adjusting the digital filters - not at all like tone controls on an amplifier - and the phase of the digital signal. Nor can I give any individual characteristic to interconnecting cables whether they are optical fibre, USB or digital audio. Sorry expensive hifi cable manufacturers.

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