I2S from computer's soundcard?

[dc]

Is it possible to get an I2S signal out of a soundcard?
I saw some new digital amps at AES this weekend that accept I2S input, which makes me wonder whether it's possible to get an I2S signal out of a computer's soundcard. Anyone have any idea?

digital amps are at: www.d2audio.com

Thanks.

Brad

 

[deandob]

Its rare to get I2S from a soundcard although some of the Creative Soundblaster models have provision for I2S (not recommended as they resample 44.1Khz to 48Khz). A couple of the pro soundcards feature I2S (eg. Hoontech) but you pay more for these and their drivers are not ideal for consumer use.

Another alternative is to simply take off the I2S lines from the input to the DAC chips on the card. Dont run them for long lengths though.

Regarding digital amps, have you heard the D2Audio amps & do you have a price? An alternative is to buy a panasonic XR10/25/45 digital consumer amp and hack away (there is another thread on this board discussing this).

Regards,
Deab

 

[dc]

I've seen the Panasonic thread, but thanks for pointing it out. The D2Audio amps offer a number of additional DSP features -- digital xo, 3- to 5- band parametric EQ, time alignment, and significantly more power than the Equibit models in the Panasonic units.

I heard the D2Audio amps at AES yesterday, but it wasn't exactly a good environment for critical listening, so, it's hard for me to comment on sound quality.

The pricing was a bit confusing to me, and the way it was presented makes me think that they haven't fully worked this out, yet. I'm sure it's model-dependent, but for the model I'm interested in (Professional model with 1x 75W, 1x 125W and 1x300W), the price I was quoted was ~$200 per unit. This doesn't include a switching power supply (probably around $200, but not something D2Audio sells). Software to control the units is included in this price.

If these only sound half-way decent, it's a bargain. Note that Harmon International has placed a major order for these units. I don't know whether they'll go into their higher-priced or lower-priced lines, though.

 

[dwk123]

Interesting - they seem to be a supplier to OEM's - did you get the impression that they would sell in small enough quantities to make purchase by end-users feasible?


As for I2S out of a soundcard, what is your intended application? The best bet is probably the ST-Audio (formerly Hoontech) DSP24 - it is designed for use with external boxes (a/d, d/a, spdif etc), and from all appearances looks to have all the envy24 i2s lines present on the expansion connector. I don't believe this port is documented, though, so you'd probably have to do some sleuthing to determine the pinout. The M-Audio Delta 1010 is similar, but more expensive as you can't get it without the external box.

Each of these will have 4 serial data lines, giving a total of 8 channels.

 

[dc]

Interesting - they seem to be a supplier to OEM's - did you get the impression that they would sell in small enough quantities to make purchase by end-users feasible?

This never really came up. Thinking back about the conversation, I asked about pricing for multiple eval boards and discussed my own needs for the new front speakers I'm building. The sales rep never indicated small orders weren't possible. Also, I did ask about the 'custom' crossover listed in their literature. If you look at the .pdf spec sheeets in the crossover type, the last one item listed is 'custom'. I asked whether users could enter coefficients for high order crossovers and the answer was "I don't know if that's available in the software as it stands, but, if we had a high volume order, we might be able to do something on a special order basis." I'm hoping to order a couple of eval boards within the next few weeks, so, we'll see what they say when I try to place the order....

I didn't answer your question re my intended application in my first reply. I'm looking for amps for a pair of 4-way loudspeakers I'm building. I'd like to go directly from my PC to the amps via I2S. Ideally, I'd like to be able to mount the amps to the sides of the loudspeaker boxes (the 1x75W, 1x125W, 1x300W model would be used for tweeter, squawker and upper bass, all of which are dipole -- the subs will be a pair of two 18" McCauleys bolted together on opposite sides of a sealed box).

What I'm really interested in doing is high-order linear phase crossovers (FIR). The guy I spoke with was a hardware guy and didn't know whether the DSP used FIR or IIR. My understanding is that in order to emulate conventional crossovers (L-R, Bessel, etc.) IIR is usually used (in fact, I think it has to be used to accurately replicate the nonlinear phase response of Bessel, L-R, etc.). I sent their East Coast sales rep a question on this and whether the parametric EQ is done via FIR or IIR this afternoon. I'll let you know when I get answers to these questions.

Another interesting new product at the show this weekend was the FIR X1 from Stage Accompany. It's a brand new product (the one at the show was the only unit in North America, and was brought in a couple of days in advance of the show). The rep I spoke with said that it should run about $2,000 - $2,500. It's another loudspeaker management product, but, it's supposed to do things no other unit on the market can do (what those things are, the rep didn't know...). In any case, their digitally-controlled analog EQ units have an excellent reputation, and I'm guessing this FIR X1 unit will live up to the Stage Accompany reputation. From the name alone, I'm guessing that at least the crossovers use FIR filters.

Other interesting news came from the ICEpower rep who told me that DIYers should be able to order the ICEpower amplifier modules in small quantities. I tried this once about 18 months ago and got rejected, but, maybe their policies have changed? Given the price and DSP benefits of the D2Audio solution, I don't see much reason to chase after ICEpower.