timbley Posted March 14, 2005 Share Posted March 14, 2005 I have an M-Audio computer sound card which has pro and consumer spdif settings. I notice that the pro setting sounds brighter, which I can verify by looking at the RTA on my Behringer DEQ. The consumer setting has a slight roll-off of the highs, while the pro setting looks perfectly flat. Why would there be this difference? I don't understand if EQ is being applied digitally by the card, or if the bits are being interpreted differently? I find it very peculiar. I've read explanations of pro and consumer spdif, but none of them explained a difference in frequency response. Quote Link to comment Share on other sites More sharing options...
DrWho Posted March 15, 2005 Share Posted March 15, 2005 Is it discussed in the user manual / help file? Quote Link to comment Share on other sites More sharing options...
sfogg Posted March 15, 2005 Share Posted March 15, 2005 There shouldn't be any difference at all between a pro and consumer digital connection. The digital data stays the same either way. What changes between those two settings is the extra bits in the S/PDIF stream (there are 32 bits per sample per channel, with no more then 24 bits used for audio data). Those other bits handle things like SCMS, data about the music among other things. Once of the other things is pre-emphasis. The position of those other bits and what their meaning is changes between consumer and digital streams. My guess is whatever you are connecting to doesn't 'know' how to read those bits properly for a 'pro' stream and it might be mis-intrupretting something else as telling it to turn pre-emphasis on. That would make it sound brighter. Shawn Quote Link to comment Share on other sites More sharing options...
Marvel Posted March 15, 2005 Share Posted March 15, 2005 On my M-Audio card (Audiophile 2496), the only difference between the two settings is output gain. The consumer is -10db. the professional is higher. I don't think it is +4, but it is higher. I am at work right now or I would check. Marvel Quote Link to comment Share on other sites More sharing options...
sfogg Posted March 15, 2005 Share Posted March 15, 2005 Marvel, " the only difference between the two settings is output gain. The consumer is -10db. the professional is higher. I don't think it is +4, but it is higher." There is no gain difference between pro and consumer bit on S/PDIF digital connections, both are fixed at 0dBfs. Are you maybe talking about an analog output from the card? The levels you mentioned are about right for the difference between professional and consumer analog signal levels. Shawn Quote Link to comment Share on other sites More sharing options...
Marvel Posted March 15, 2005 Share Posted March 15, 2005 Shawn, Yeah, I wasn't thinking of the digital out. I'm still sorta in the analog world. I still pull everything off my ADAT through the analog outs on it (20 bit). Marvel Quote Link to comment Share on other sites More sharing options...
timbley Posted March 15, 2005 Author Share Posted March 15, 2005 ---------------- On 3/15/2005 8:56:07 AM sfogg wrote: My guess is whatever you are connecting to doesn't 'know' how to read those bits properly for a 'pro' stream and it might be mis-intrupretting something else as telling it to turn pre-emphasis on. That would make it sound brighter. Shawn ---------------- Thanks Shawn. I'll leave it in consumer mode. Tim Quote Link to comment Share on other sites More sharing options...
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