Fireface and Altman DAC

[Leo]

My report on the Fireface 400 with Altman DAC

Start Audio Device Analysis Exclusive Mode support
03AFFD38

    Supported : 2|16|44100|176400|4
Not supported : 2|24|44100|264600|6
    Supported : 2|32|44100|352800|8
    Supported : 2|16|48000|192000|4
Not supported : 2|24|48000|288000|6
    Supported : 2|32|48000|384000|8
    Supported : 2|16|88200|352800|4
Not supported : 2|24|88200|529200|6
    Supported : 2|32|88200|705600|8
    Supported : 2|16|96000|384000|4
Not supported : 2|24|96000|576000|6
    Supported : 2|32|96000|768000|8
    Supported : 2|16|176400|705600|4
Not supported : 2|24|176400|1058400|6
    Supported : 2|32|176400|1411200|8
    Supported : 2|16|192000|768000|4
Not supported : 2|24|192000|1152000|6
    Supported : 2|32|192000|1536000|8


Real 24/96 files from iTrax are a delight, but upsampled 16/44.1 is not so bad either

Leo

[SeVeReD]

Stop making me jealous

Start Audio Device Analysis Exclusive Mode support
040FFD38

    Supported : 2|16|44100|176400|4
Not supported : 2|24|44100|264600|6
Not supported : 2|32|44100|352800|8
    Supported : 2|16|48000|192000|4
Not supported : 2|24|48000|288000|6
Not supported : 2|32|48000|384000|8
Not supported : 2|16|88200|352800|4
Not supported : 2|24|88200|529200|6
Not supported : 2|32|88200|705600|8
Not supported : 2|16|96000|384000|4
Not supported : 2|24|96000|576000|6
Not supported : 2|32|96000|768000|8
Not supported : 2|16|176400|705600|4
Not supported : 2|24|176400|1058400|6
Not supported : 2|32|176400|1411200|8
Not supported : 2|16|192000|768000|4
Not supported : 2|24|192000|1152000|6
Not supported : 2|32|192000|1536000|8
 

[PeterSt]

Leo (and everybody !),

As far as I can tell, what you see is the Fireface. So, it won't look through to the Altman.
Now, since (as far as I recall) the Altman won't accept 24 bits for input, you'd be playing 96/24 through the Fireface indeed, but then into the Altman the last 8 bits will be cut off.

That you can still perceive this as good is another matter, which is because at the level you play the lower 8 bits (or attenuating 48dB) will be lost in the noise anyway. Supposed you attenuate 30 dB (you could check your level of attenuation with the volume slider of XX with the pre-amp at max) you'd loose 2 bits compared to normal 16 bit data. We know by now how that can sound (read : very OK if you only let XX do the attennuation).

All 'n all, the Fireface provides you a means to play 96/24 files. When you'd be able to connect the DAC directly, I don't think it can ...
Can I be right ?

For Dave : you could do it too my such means.


Another thing : sadly I don't have any 96/24 sources with music I could compare with.
What would be true, is that you have a means of playback of these files, which becomes important when the album etc. is not available at a lower rez.

[Leo]

I'll have to dig out the Maudio Transit then , instead of the Fireface. I think & hope that you underestimate mr Altman

[Leo]

Hello Peter,

M audio would not install, lousy VISA drivers, has worked before,but unreliable so. I now instead of the Fireface 400 use the Edirol firewire FA 66. Both the Edirol and the Altman have to be set manually at freq., so the DAC test with a 44.1 testfile will only give 44.1 in ther report.
But when set to 96 kHz both XX and I am happy.
I am now listening to 24/96 Acoustic guitar from iTrax through Edirol and Altman at 96kHz and it sounds better than 44.1 (I think, no direct comparison). So assuming that by 'direct' you mean instead of the fireface use another interface between PC and DAC, I think I did.
I work now with passive attenuation to be ready for 44.1 upsampled files, as you suggested. The prvious days I used the XX volume, very very nice improvement.
Looking forward to further tests and suggestions you have for me.

Leo

[PeterSt]

Leo,

I now realize that "direct" isn't much possible with SPDIF. So what it comes to is this :

When you set everything to 44.1/16, you will notice destortion when you attenuate too much. Never mind at which level this is, at some point you will start to hear "radio" sounds, which are in fact the harmonic distortions of throwing out too many bits. No, remember this level (of the XX volume slider).
Now connect everything like 96/24 (or 24 anyway !) and again play the 44.1/16 file at the same level;
If the distortions have gone and instead you hear normal music, you will have used more bits (in the Altman).

Keep any other volume sliders at 0dB ! (like from the Fireface).

[Leo]

Hi Peter,

I missed your fast reply yesterday, among all the action at the forum. I will try this suggestion of a comparison of bitrates at the same volume, probably tonight and report back.

Even if it turns out to be only 16 bits, it still sounds very nice...

Leo

[Leo]

Well I tried it. With 16/44.1 files I get distortion at -54dB. When I use 24/96 files I get comparable distortion (I think, very low volume!) at -66db. The volume slider turnes red with the -54 db with 16/44.1 , probably from shame for the SQ at that setting. It stays virgin-white with the 24/96 files.

Now I am back to listening !