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RE: Squeezebox vs. EMU 0404 USB as Transport for SPDIF

67.164.165.165

In Reply to: RE: Squeezebox vs. EMU 0404 USB as Transport for SPDIF posted by Dawnrazor on February 06, 2008 at 19:07:14

Do you adjust the volume with your software, or does the emu output a full unattenuated signal? and the benchmark or further up does the volume?

Hi Dawnrazor,

The only digital volume adjustment I do is in the Berhringer unit itself, to avoid digital clipping due to the digital filtering it provides (for the bass only). When this occurs, it's very audible as a crackling sound, but can be eliminated easily by looking at the VU meters of the Behringer, which have a digital clipping indicator, and adjusting the digital level to prevent the clipping. To help with that, I use a reference CD (Miles Davis' "Milestones" - the track "Two Bass Hit"). This song is recorded very loudly, and shows up digital clipping clearly on the Behringer's VU meters. I adjust the Behringer's digital volume control for the minimum attenuation that avoids digital clipping. This ends up being about 2 dB with my setup.

I have disabled the front panel volume control on the Benchmark, and instead use the volume control of my preamp, which can be controlled using the remote. However, I still use the multi-turn volume control trimmers on the Benchmark's real panel as follows:

1) To reduce overall volume such that the remote volume control of my preamp is in a range where it's not jumpy.

2) To get matched volumes between channels at a typical volume setting.

I do the first step empirically. I determine where the preamp's volume control needs to be set in order to get good control with the remote. Then I do a coarse tweak with the Benchmark's rear-mounted trimpots to get close.

To get precise channel matching, I first set the preamp's volume control to match that of typical listening. Then I play a mono WAV file of a sine wave of about 500 Hz. Using an AC voltmeter, I match the measured voltages of the preamp's left and right outputs with the voltmeter by varying the adjustment of the Benchmark's multi-turn pots in back. I can get channel-to-channel matching within hundredths of a dB at the normal listening level. This is possible even with a cheap AC voltmeter, as long as the display is digital (so you can read to the desired resolution).

In practice, this works great. Matching the two channels like this eliminates the "audiophile nervosa" effect from channel mismatch of conventional preamp volume control pots. Integrated circuit control of volume has better matching than motorized pots, but depends on using MOSFET switches in the IC, which cause distortion. The best approach is multi-position switched attenuators, but these get complex and expensive. Using a preamp with a motorized pot, combined with individually adjustable outputs of the DAC, works well for me as an economical solution. YMMV.

Follow Ups:

Ok. Here is a player that MIGHT work - Dawnrazor 21:41:56 02/06/08 (1)
Since you are having problems with Foobar and Winamp, and no one else seems to have any issues with them, I am assuming that the creative drivers are part of the problem.

Here is a player with native ASIO support that has a trial. You might get lucky here but probably not. Its ASIO does not allow volume control, so you will be OK.

Its GUI is one of the best I have seen even better than Mp3toys IMHO. It is powerful and somewhat rather unintuitive in some areas due to its power.

I recommended it to a gentlemen who was struggling with Foobar and his classical collection. It allows you to group albums by Composer, or Orchestra or Conductor among 15 other categories. I thought it would be perfect.

Well he had problems getting the library set up and since he never told me how the hell he had his files configured I couldn't help.

It will set up a library based on file directory (say individual Artist/ album folders and .wavs ) or by tags if you have a .flac or mp3:

For kicks, I have set up a library based on tags (for my spooky mp3s) and a library of my .wavs using the file structure option. Both worked great.

It has some interesting features that I haven't yet delved into, and its "playlists" (custom collections) are pretty interesting. It will also random all you albums or songs and you can get pretty specific on how that works.

May be worth a try. One day I plan to test it soundwise, since it supports Winamp DSP plugins, I wouldn't be surprised if it is the same asio driver as winamp, and sounds similiar. But i don't remember having to do ANYTHING as far as mapping. I did with Foobar. So the offset you mention might trip this up.

The demo shuts off after 15 minutes but you can restart it.

Let us know if this works.
- http://www.albumplayer.com (Open in New Window)
- RE: Ok. Here is a player that MIGHT work - andy_c 16:41:07 02/07/08 (0)
  Wow! Thanks for that info Dawnrazor. I will try it out this weekend also.
  
  I just downloaded JRiver, and it seems to be working just fine for me. No truncation of the end of a track in gapless mode, and gapless mode seems to work perfectly. I'm going to do an extended listening session this evening, so I'll see how it goes.

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