Direct S/PDIF recording

Doomsayer

I'm trying to record guitar using Direct SPDIF recording through Line In 2 on my Audigy Drive (I2S 0). I'm a little confused, because in the Playback/Recording guide it is mentioned that I2S operates at 96/24 by default.
But this is what kX tells me :
I2S Inputs: (0): 48000Hz [R] (1): 48000Hz [R] (2): 48000Hz [R]
In my recording app (SoundForge 7.0) the only correct bit precision/sample rate combination appears to be 16/48000.
My question is whether there's a way to direct-record 24/96 from I2S?
Btw, even in 16/48 the improvement in signal/noise ratio is amazing in direct mode.

----Hardware / Software configuration---------------
Driver Name:kX Audio Driver (Debug)
Driver Date: Feb 17 2004 00:43:22
Driver Version: 5.10.00.3537 - debug
DB Name:LiveBay2
SB0092 10k2 [d000]
PCI Information:
Device: 41102 Subsys: 531102 ChipRev: 3
Card is '10k2'
Card has MPU device
Card model is '5.1'
Card HAS AC97 codec
Codec name: SigmaTel STAC9721/23
3D Extension: SigmaTel 3D Enhancement
Codec is 2.0 compliant
Capabilities[6940] :
DAC resolutions : -16-bit- -18-bit-
ADC resolutions : -16-bit- -18-bit-
Ext Capabilities [200]: -slot/DAC mappings-
Port: d000 Irq: 0x16(22)
Playback buffer: 20a0
Record buffer: 4000
Number of AC3 buffers: 4
Tank memory: 256 kb
GSIF buffer: 256 samples
OS version: [2 5 1 Service Pack 1; 2 5 1 Service Pack 1; 156 148]
----------------------------------------------------

dj_stick

i don't think direct s/pdif recording works with the i2s inputs…

Doomsayer

It does, I assure you Makes the noise on line input go below -70db with guitar plugged in! (meters in SoundForge won't go lower, so I can't be more precise).

dj_stick

try the kX or ufx peak metres

Doomsayer

I see that you haven't examined it yet, you should take a look at the docs section on the main site. In Direct S/PDIF recording mode the signal bypasses the DSP completely! No resampling = bit-to-bit recording (from an ADC in my case).

dj_stick

oh yeh sorry i had forgotten that bit… for some reason i thought you were still in the DSP maybe i need more sleep, but i am pretty sure the i2s codecs are not 24/96 compatible… or at least the converters aren't

TravelRec.

Hi there!

I2S works fine with direct recording mode. I2S is (from specification) able to work from 32 to 96 kHz (like SPDIF) and from 16 to 24 bits resolution. Dependent of what you have applied at the input, the frequencies are shown in status window. Since the audigy drive frequency is locked with the card´s own frequency - 48k - the status and so the input frequency of I2S is 48kHz. BTW I try to connect a sample rate converter to the AUD_EXT I2S that makes a conversion of all input frequencies to 48 k, since the card´s I2S must be syncronized with the main frequency in order to work properly with the DSP - hardware limitation.

Greetings!

TravelRec.

Doomsayer

I agree that locking to 48k makes sense, but not when we're doing direct recording! This is a quote from the "Playback and Recording guide" : "Also note, that i2s codecs always operate in 24/96 mode by default (and the preset driver implementation doesn't change this setting)." So I still don't get it - is it theoretically possible to record 24/96 in this mode from I2S or not?

dj_stick

im pretty sure to save money on the live drive, they used only 48khz chips due to the DSP, it may be the i2s outputs that are always in 24/96