PC music players

[mhoev]

Shelving FIR filters...

This is really an incredibly informative thread! Thanks a lot to all of you who contributed to it!!

Currently I am thinking of using BruteFIR as an active crossover for a 3-way dipol speaker. Calculation the parameters for low- and high-pass filters seems to be quite straightforward using fir1 in octave-forge. But how to generate the parameters for a shelving low-pass filter needed for the bass drivers?

Thanx for any hints!!
Markus

 

[jkeny]

I have a question which may be stupid

If using Brutefir on a Pc to do a digital crossover for a two spaeaker can it output through the soundcard a spdif signal which comprises four channels (left tweeter, left woofer, r tweeter, r woofer)? i.e not use the analogue outs of the soundcard.

John

 

[MWP]

If using Brutefir on a Pc to do a digital crossover for a two spaeaker can it output through the soundcard a spdif signal which comprises four channels (left tweeter, left woofer, r tweeter, r woofer)? i.e not use the analogue outs of the soundcard.

No it cant... SPDIF only supports 2 channels.

 

[jkeny]

Thanks for the reply MWP - so Brutefir only outputs on the analogue outs of soundcard

I was thinking along the lines of a program to do digital Xover (for a two way speaker) in PC - output digital signal for the 4 channels (along the lines of 5.1 channels from DVD audio) into a receiver like panasonic SA-XR* and connect left tweeter to say left surrond speaker output, right tweeter to right surrond, L woofer to Left front, R woofer to R front.

Is this feasible in any scenario?

John

 

[peufeu]

Setup a Linux system. Use ALSA as your sound driver (should come as default anyway now). Make sure you have the drivers for your soundcard ! Check your output, watch a DVD in 5.1 from your computer...

If you have an analogue multchannel card (5.1, whatever) you can use this.

If you have a soundcard with a digital out, obviously SPDIF is only Stereo but if you have ADAT you can surely plug this into a multichannel receiver, it does upto 8x 16/48 on one optical fiber.

A mere old SB Live does not sound that good but it'll give you an idea of what a digital crossover can do before you buy some decent multchannel card (RME, Lynx, Delta...)

http://alsa-project.org/

http://www.ludd.luth.se/~torger/brutefir.html

Once the thing works you can use Jack to connect your favourite player (for instance XMMS) to BruteFIR, so that its output is seamlessly redirected into the active crossover. No need to use the command line to play music !

http://jackit.sourceforge.net/

http://www.xmms.org/

Have fun !

 

[B.I.G]

is there any way i could use a digital crossover in windows ? ?

i got the foobar2000+crossover plugin and i like it but it only works on foobar2000 on other aplications i don`t have any crossover

 

[BlackDog]

is there any way i could use a digital crossover in windows ? ?

i got the foobar2000+crossover plugin and i like it but it only works on foobar2000 on other aplications i don`t have any crossover

You could any sound card supported by the kx project. - ie SB Live!, Audigy or Audigy 2 (not Audigy 2 ZS), and using the kx DSP app. you can do pretty much anything you want. - You'll probably want the "Plugins in Uniform" plugin as well. (there's a thread in 'speaker forum about this)

The best part of this is that there's absolutely no CPU overhead, as all the work is done on the soundcard's DSP chip. - I'm about to try this with a dedicated PC and Audigy 2 card. I just need to plug it all in and play to my hearts content..

Steve

 

[MWP]

Thanks for the reply MWP - so Brutefir only outputs on the analogue outs of soundcard

I was thinking along the lines of a program to do digital Xover (for a two way speaker) in PC - output digital signal for the 4 channels (along the lines of 5.1 channels from DVD audio) into a receiver like panasonic SA-XR* and connect left tweeter to say left surrond speaker output, right tweeter to right surrond, L woofer to Left front, R woofer to R front.

Is this feasible in any scenario?

Yeh, its what i do.

But i had to heavily modify my soundcard and build my own amp to do it.

 

[wytco0]

ttt to see if there are any updates.

I am still watching the development of these sort of solutions, but starting to think the time to build something myself is near.

 

[johnthedoctor]

There's very little info on modding the PC itself or which mobo to use. Surely not all motherboards are the same when it comes to electrical pollution but you'd think so from the lack of info about them.

What's the minimum cpu speed we can get away with?

Any advantage to giving a separate supply so say, hard drive, ram etc?

Is getting a clean digital signal from a dedicated music PC really so impossible?

 

[Daveis]

PC as Crossover

in Response to B.I.G...

I'm using a PC as crossover under Windows.

Under one configuration I use

Sony CD Jukebox into
RME sound card input into
Console VST plugin host into
Voxengo Gliss EQ plugin to
RME ADAT output into
Aleis AI4 Adat breakout box into
Multiple Benchmark media DAC1's into
amps/speakers

In another configuration I use any Windows music player out the motheboard soundcard looped back into the RME sound card inputs. The rest of the music path is the same.

Voxengo also has a Pristine Space convolver for conceivably doing Digital Room correction, etc. I haven't explored that though.

The downside to digital crossovers is that so many modern albums are recorded so close to 0db that there's no digital headroom to do EQ in crossover. You end up digitally clipping alot of albums and that doesnt sound good.

Another problem is that the latency of even a good low latency ASIO soundcards, is maybe 250 milliseconds in this configuration. If I push the latency too low I get stuttering audio. This makes it unsuitable for movie's where you want the audio and video to be in synch.

I experimented briefly with VST plugin FIR based filters but found the sound to be "digital". Maybe Brutefir running under Linux sounds better, but I definitely prefer the sound of digital IIR filters over FIR.

In conclusion, I'd say that using the PC crossover is great for trying to voice and tune a crossover for a speaker building project. But it's been a lot less general purpose than my previous Behringer DCX2496 crossover. (Even the Behringer supposedly has 100 millisecond latencies making it questionable for movie audio/video synch.)

 

[Brent Welke]

I have made some progress

Sorry I haven't read the whole thread, at least not in a while. If I am off topic then please forgive me

I find that to get good sound the power supply is very very important. An external USB DAC is my solution. SPDIF and optical have sound quality problems.

I downloaded a few high end digital filters and found that any filter I tried had a negative affect on the sound quality. I was hoping it would not be the case as I had plans to do a digital XO. Maybe my tests were not extensive enough, but I can hardly see many going to the lengths I did.

A digital XO is nice to experiment with but not something to live with in my opinion. Math in = math out.

 

[peufeu]

I have started a new thread for my next project :

http://www.diyaudio.com/forums/showthread.php?s=&threadid=85473

I want to build a multichannel PC based DAC, it will probably use Ethernet. Waiting for your comments gentlemen !

 

[Daveis]

Re: Why use S/PDIF?

So why use a synchronous datastream from a PC when we can use an asynchronous stream, buffer and clock the data out at the DAC end using a precision clock source. Therefore totally eliminanting the inherent problems with S/PDIF and infact creating a 'better' transport than any CD could

Yup, assuming your CD rip with EAC is as flawless as you are going to get. And assuming your buffer is something like 128MB, enough to hold a complete song. Or maybe even 1GB DRAM, enough to hold a whole CD at a time.