Active Crossover using PC and multi ch. Soundcard?

[vision]

There is a soundcard called M-Audio Delta 1010. 10-in, 10-out (SE and Balanced), and 2-SPDIF in and out. The audio circuitary is in the external rack housing to protect it from computer noise. This is mainly used for recording studios, but growing number of people uses it as a Home Theater Processors (with approprate softwares for 5.1, 6.1, even 7.1..). There are many other similar cards in the market currently.

I wonder, if it would be possible to use this as an active crossover. The spec of the soundcard seems to be really good, and with a proper software , it would be really easy to modify crossover slopes/frequencies as well as adding other filters and etc.

Take the audio signal through SPDIF input or XLR input, then process it, and output through XLRs... there are 10 outputs available... so two channel, three way would occupy 6 outputs... Volume control is either done in software, or externally if Analog input is used. Afterall, the CD's that we listened to, may have been recorded and processed using this kind of gear.

I guess the beauty of such system is the flexibility of configuration.. 6db,12db,24db... 2 way, 3way, 4 way... 2 ch, 3 ch, 4ch.... All filtering and X-over'ing is done in digital domain.. I guess the performance of the software and driver would be the only barrier...

Sounds too good to be true...

any thoughts?

[Sparhawk]

I have a Gadget Labs Wave 8/24 (8 in, 8 out, balanced, 24 bit, rack mount). I never thought of using it as a crossover, but it's an interesting idea. I don't see why it couldn't be done, with the appropriate software. That is, if such software existed.

[daatkins]

I suggest you look at Don Maurer's web page:
http://home.pacbell.net/donwm/

He's using a Delta 1010 Soundcard and custom PC software to reproduce the charactristics of the Linkwitz Pheonix crossover.

Nice one.

David.

[Won]

Why stop here? Why not DIY room/theater correction?

-Won

[alvaius]

If I remember correctly, lspCAD pro for speaker design allows you to simulate cross-overs with a multi channel sound card.

May have been a different on, not sure.

Alvaius

[MWP]

Wow... you guys need to look at NWFIIR and BruteFIR.

Excelent tools written fro exactly this on a UNIX (probably Linux) box.

Just as an example of how powerful BruteFIR is, it can do a 3,000,000 tap FIR filter on a mono source realtime (in on soundcard, processed, out on soundcard) on a 1Gz Duron PC.

Its is very configurable, and is perfect for room EQ and other FIR filters.

[hifiZen]

unfortunately, BruteFIR is not a genuine FIR engine, it is based on FFT

[jerry]

hi,
do you know the kxproject, at www.kxproject.com.

The kX Audio Driver is an independent WDM (Windows Driver Model) driver for all EMU10K1 and EMU10K2-based soundcards manufactured by Creative Technology Ltd. and/or E-mu Systems Inc., including the SoundBlaster Live! series, the E-mu Audio Production Studio (APS) card, and the Audigy series of cards.

The kX Audio Driver package includes driver system files and setup files as well as a powerful audio mixer application (the kX Mixer), which acts as a Graphical User Interface, providing access to many of the driver's internal functions.

The kX DSP applet represents the internal connections of the kX driver graphically, and is one of the most powerful features of the kX Audio Driver. Signal routing is done by connecting virtual inputs and outputs with virtual cables in which the digital sound streams are being transmitted, in the same fashion as you would use patch cords to connect different units in a sound studio or in a home stereo setup.

Adicionally, to get started with creating your own DSP effects, is available to download the kX API / SDK, for guys with knowledge in C/C++ programming, MFC, Visual C and DSP programming techniques.

[tschrama]

I've been thinking about that too for some time. The beauty to me is that you can programm a zero-phase shifting filter and use whatever slope you want. Rhis will however cost alot of computing speed memory and requires some programming, datacontroll.

gr,
Thijs

[fcserei]

Not a PC, but I'm using an older (1998) EV (Telex) digital crossover now.
The EV is a black box with 2 ananlog 1 digital in, 6 analog 1 digital out. Uses 3 Motorola 66 MHz fixed point DSPs with freely configurable signal processing.
Controlled with a pc program over a serial connection you can draw the necessary signal processing ( selectors, attenuators, mixers, filters, 2-4 way crossover, compressors, limiters, gates, delays, output dithers etc ) and download to the box for offline use. Analog inputs and outputs are 24 bit cyrrus chips. I'm going to upgrade them to PCM1792s once they are available.
It was designed to 48kHz sampling but can syncronize to 44.1k too, so can use cd without ASRC. ( It is a selectable option, and a big donwngrade in sound whenever I switch the ASRC on)

The sound is very, very good not to mention the total control over the speaker setup now - from crossovers to driver delays and room correction. I'm using 18" ELF woofer from 15-35Hz, 2*18" dipole woofer from 35-250Hz, a Goodmans Axiom80 in a straight front horn from 250-18k and a supertweeter above 16k.

Too bad there is no comparable product on the market now. The dbx driverack is symply terrible sounding (I suspect lousy floating point algorithms). The Rane RPM26z is similar to the EV, but has a permanent ASRC on the input and only 48k internal sampling (althoug with a little diy both could be fixed) and about $800. BSS and others use 96-192kHz now (and use the dreaded ASRC too), fixed signal processing architetcture and more like 2-3 grand.

Simply put it the EV is a fantastic tool and the best improvement I had in a long time. And the cost (used) was below a decent computer configuration - not to mention the price of a rack mount multiple output sound card.