Instant Crossover Prototyping

[bzdang]

This is just too useful to ignore.

I've attached a picture of a mono crossover implemented in the dsp of my dirt-cheap Audigy sound card using the kxproject drivers.

L-R 24 crossover, couple of parametric eq for baffle-step correction, a notch at tweeter resonance frequency, easy level and phase adjustment, and a fine-adjustable delay for time-alignment. Six output channels and enough dsp memory for a three way stereo crossover with many EQ and delay modules.

I'm driving gainclones direct from the output jacks on the soundcard.
Noise is almost inaudible at the loudspeaker with everything cranked up to full volume, even with radioshack interconnects, my dreadful soldering, and the soundcard living inside of my fire-breathing lunchbox computer.

I crowded all of the controls into a small area to get the screenshot but you can spread it all out on your screen. All of the controls can be adjusted in real-time with music playing through the crossover. You can save and recall crossover setups. I have run the crossover with measurement software and an even an RTA on the computer so I suppose that room correction would be possible if I cpuld find the time and mental-energy.

An Audigy1 dsp soundcard costs US$45.00 and the kxproject drivers are free.

[bzdang]

Here is a setup with subwoofer. A crossfader control allows me to go back and forth from full range satellites only, to sat+sub+crossover.
My MLTL project speaker goes fairly low in its current location, and the nasty horn p.a. sub not much lower, so if I set levels carefully, I can drag the crossfader, bring in the sub+crossover, and just hear the vocals go from less-clear to more-clear.

[rcavictim]

bzdang,

Living in proximity to that nuke reactor doesn't seem to have affected your creativity. That is pretty darned cool. I just recently bought an audigy second hand to use in my sweep testing suite and have no idea what all it can do. Thanx for sharing this!

[bzdang]

You're welcome
Yes, proximity has its perks - Lake Ontario is cold ! but on the Labour Day weekend the wind was southeast and blew outlet water from the power station onto the beach, it was warmer than our swimming pool, and breaking waves too! Mini-Me got to play in the surf for the first time. Free beach day courtesy of Ontario Power Generation.

There's a signal generator device in there. It's facinating to set it to 1 or 2 Hz and watch the woofers move.

The links:

www.kxproject.com

DriverHeaven.net - kX Project Audio Driver Support Forum
http://www.driverheaven.net/forumdisplay.php?f=67

[ekaerin]

What is there to add....
I'm greatful and impressed. Really nice.

Now is the time to go and get a new soundcard.

/ Mattias

[bzdang]

Additional Info

Plugins in Uniform ("UFX") are an essential part of the crossover.
Here is the thread describing them...
http://www.driverheaven.net/showthre...&page=1&pp=100
The file...
http://kxdev.narod.ru/ufx/ufxsetup.37.exe
A mirror...
http://www.electricstart.de/plug/ufxsetup37.exe

The crossovers are included in the UFX package, but here is the thread describing them...
http://www.driverheaven.net/showthread.php?t=31846

[Raka]

Yes, those drivers are nice, specially the DSP panel, absolutely fantastic.
Be careful and don't run to buy the latest Live! souncard since is the model SB0220 and it's not supported yet. The audigy LS (the new and cheapest one) is not either, since it doesn't have the 10K1 chip.

[Kittle]

neat looking stuff.

I cant find a 'search' button anywhere on that site. anyone know if they support the turtle beach cards?

[bzdang]

Yes this is good stuff I agree. This software reprograms the dsp in creative soundcards which contain the 10k1 and 10k2 dsp chips originally created by EMU for their APS professional sound card. There is a list of compatible cards on the kxproject website. Creative bought EMU and used the dsp to produce a new product called the 'Live!'. Audigy products are decendants of the Live. As Raka pointed out, Creative is selling soundcards that exploit the Audigy brand name but don't have this dsp. Beware!

Easy and painless to implement but you do have to do some reading, part of the main website and at least the sticky posts on the support forum first. You will be replacing the creative-supplied software drivers and will need to have a clear idea of what you're doing.

You will be creating signal sources which might (and probably will) send max volume audio to your amplifiers at some point, and you might make mistakes which send low frequency audio to tweeters, so get some practice before hooking up powerful amps and expensive drivers. Computers have a habit of finding the most terrible things to do and doing them at the worst time (11:30pm when the kids are sleeping) so you have to be on guard at all times. I always run my computer volume controls loud and control volume outside of the computer so that I don't get any surprises.

[bzdang]

Response to question posted in this thread -
http://www.diyaudio.com/forums/showt...396#post494396

Originally posted by m0tion
Sorry to hi-jack this thread, but I've got another question regarding this project. Let me give you a little background info:

I had planned on moving a PC into my home theater to use for some music and dvd playback, games, etc. Also I plan to build a pair of 3-way active crossed main speakers (read Left and Right) to be used in my theater. I would be using my Hercules Fortissimo III card for audio playback (and the SP/DIF out to my reciever for DD/DTS playback).

Is this possible?:

Install a creative card as well and use the input on the creative card to take the output from my recievers pre-outs for the Left and Right main speakers, and use the kxproject to output that material to the 6 outputs of the creative card and use it as a 3-way stereo crossover, all without disturbing the Hercules Fortissimo setup. To state it another way, I want to use the kxproject with a creative card inside a computer where no other programs would use the creative card, they would all use the Hercules card.

Again, pardon my interruption and thanks for the advice.

Thought it would be best to respond here.
I'm perhaps a year away from setting up a home theater so I haven't investigated these issues yet.

I made a simple test tonight, hooked up an external audio source to the line in on my creative audigy card, set up the dsp to route line-in through to the outputs, and music came out of the audigy. Then went to the windows control panel, sound and multimedia, and I switched the 'sound playback preferred device' to my onboard soundstorm audio, started an internal audio source (iTunes), and music came out of the onboard audio system (and the audigy system was still playing it's source).

So yes I can process external sound sources with the audigy while using another soundcard as the default device for playback. For example analog output from the soundstorm system to the analog input of the audigy system, where a dsp crossover could be operating.

YMMV, and I recommend an audigy2 card if you want to use the analog inputs, as the audigy1's AC97 codec (which handles analog inputs) is noisy and was improved upon in the audigy2.

Audigy + kxdrivers supports 5.1 surround sound, and it may be possible to pass the full digital surround sound through to your receiver while also processing front left and right channels through dsp crossover and out of the soundcard analog outputs. Complicated to implement perhaps but that's what winter evening are for.
Read the driverheaven forum, try some things, and post your results!