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Foobar Convolver Plugin

Been checking out a friends Windows Media Center for a while now. Decided to start my venture into the PC audio arena by resurrecting an old desktop system as a music server for my garage/shop office.

A little about the equipment - I totally believe in isolation from desktop internals for my gear so with that, for ripping audio I have an external Plextor Premium-U (USB 2) CD writer and use Plextools Professional (error logging) for the DAE process to PCM format. The sound card is integral to the motherboard - NFG. My Media Center buddy went on vacation this week so he was nice enough to loan me his Waveterminal U24 USB sound card and a DIY TDA1543 non-oversampling DAC for me to play with (sounds great by the way in his system). So here's the rig:

PCM files > WMP9 > Waveterminal > SPDIF > DAC > Hafler SE120/100 amp/pre > Ohm H speakers

Sound is very good, but at times a little bright. I tried fiddling with the U24 control panel but any changes I made left me with either polluted or no sound at all. Decided to try a different player. I kept reading about Foobar and it's exceptional playback qualities and decided to give it a try. Big mistake - I like to tweak. Anyhow, I didn't realize any difference whatsoever between WMP9 and Foobar to my ears. Tried Foobar in waveout, kernel streaming and direct sound modes ( I did find an ASIO plugin that I haven't tried yet). I do like the open source and clean/low overhead aspects of Foobar though. Got to poking around and noticed the DSP manager and started looking into that when I came across the "convolver" plugin. Apparently with this plugin you can use "impulse" samples (waveform signatures?) to model other waveforms to it. Poking around some more I found impulses which model rooms, halls, cathedrals, auditoriums, guitar amps, microphones, etc. Found a great number of them here . More searching led me to a download of analogue_impulses.zip which contains a number of "tube-like" impulses. This one caught my attention. I installed the convolver plugin and started playing with the samples. Interesting effects on the sound to say the least! Of all the ones I have tried the "SPL GoldMike Impulse" has had the most pleasing effect on the sound - with no apparant degredation. I may be on to something.

Interesting little find (for me anyway). Considering the concept, one would believe that perhaps impulses of extremely high-end reference equipment could be created and applied in this manner. I'm sure you could never replicate the purity of good gear but by utilizing this method one could almost stumble upon an excellent sounding setup. Not quite sure that I have done things completely right in my testing. Seems to me that in order to do PC Audio right, there is initially some considerable investment in an external sound card and DAC. Seems absurd that I would have to ultimately "fix" the sound with software.

Of course, I am very new to the PC Audio concept. Would appreciate input from some of the veterans to critique my setup. Also some thoughts and opinions if any of you have spent any time with the convolver plugin, which in my opinion is the most intriguing element of my experimenting so far.
slothman
vdeakin
5 posts
 
Well done, Slothman.
If I may continue a little longer as a self-appointed inspiring muse... it's been mentioned on audioasylum.com (look for John Swenson in PC AUDIO forum)... to make it short, he's disconnected the voltage wires (#1 and #4, if I'm not mistaken) of the USB bus in a similar device (some Edirol) after taking it apart and replaced them with a 5 or 6 volt battery - he was plain astounded by the improvement. This could be done with either Xitel or Waveterminal.
BTW, U24 has just been discounted by 30% and can be had for $160.00.
Also, I was wondering (and, maybe, I'm plain ignorant here) if you could eliminate the preamp from the chain, I couldn't tell whether you've adjusted the playback settings by 3 db on the computer side or on the preamp. If it's the former, then maybe you could go into the amp directly. You can certainly try it regardless - there is a volume control on the PC.
I've never heard of Xitel, and, as I was looking it up, I've noticed that they supply 30' cables, which could have a negative effect, though I doubt that you've been using them.

Thanks again for clarifying the U24 qualities - I think I'm going to get it.
Meanwhile, keep us posted.
slothman OP
311 posts
 
Vdeakin

I increased the levels for the Xitel/U24 within the Foobar software. Turns out, however, that the Adcom CDP has a set of variable output connectors - I could have made the level adjustment by bringing down the CDP with the remote to match the devices. Guess I could have hooked it up that way, but the software control was just too easy - hence the term "Slothman". Also, going through the preamp with both devices allowed for efficient switching between the Adcom CDP and the Xitel/U24. By the way, I was using quality IC's(http://www.viablue.de/cinchkabel_nfa7.shtml) the one's that came with the Xitel I will use in my shop system.

I'm pretty sure I could hook the Xitel up directly to my M-120's and control volume through Windows. Unless I'm missing something, the U24 is a different animal. The control panel provided by the U24 driver is maxed out at 0db by default. Volume control is greyed out in Windows and using the ASIO plugin, there is no direct volume control in Foobar other than increasing the gain in the playback control as mentioned before.

I just looked at some posts on audioasylum concerning the Xitel - turns out that it upsamples to 48hz which may be the cause of its brightness. I had the U24 locked in a 44.1hz in my tests. I'll see what I can do about trying out the U24 directly into my amps. We've been getting dumped on here in Maine and the girlfriend is looking to get out of Dodge tommorrow for an extended weekend - little bit of cabin fever. I'll get back to you on that one. By the way, I hadn't paid much mind to the variable outputs on the Adcom CDP until you sort of reminded me. Looking forward to listening to that directly through the M-120's as well. I'll look into that battery mod also - might be something I'd be willing to try on the Xitel but I don't think my buddy would appreciate it on his U24.
slothman OP
311 posts
 
Perhaps a testament to the Adcom preamp but the CDP/Xitel/U24 appear to all have the same sonic delivery whether they are running though the preamp (bypassing tone controls) or directly to my M-120's.

Had to give back the U24 today. My buddy is going to try Foobar and my convolver impulses and see what it does for him. I will say that I am impressed with the U24's performance as an acceptable solution for tying PC audio into my home system. For now I will continue through my learning curve with the Xitel.
audioengr
3,282 posts
 
you should try to pick-up an Edirol UA-5 used. This has external power, coax out, a driver that supports 24/96 and avoids Kmixer. I recently modded the UA-25 (which is similar) to add coax out, external power and Superclock and it performs superbly.
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