A few months ago I bought a new sound card for my PC, the M-Audio Delta Audiophile 2496. As the name suggests, it works with 24-bit/96 kHz.
I had used the Creative Sound Blaster Live! 5.1 for at least ten years. But I couldn’t use MIDI for the last couple of years which was really annoying … although obviously not annoying enough for me to buy a new card. With changing from Windows XP to Windows 7 I couldn’t find a working driver. The problem is probably that I use the 64 bit version of Windows 7. I tried some drivers I found on the internet, but none of them worked. So I had to think about replacing the Sound Blaster by a new audio card.
Audiophile
Reading several recommendations in internet forums I came across the Audiophile 2496 from M-Audio. Fortunately my PC has still a PCI slot. Nowadays most audio cards seem to use the new PCI Express slot.
The Audiophile 2496 provides me with everything I need:
- 2 (left + right) analogue cinch audio inputs,
- 2 (left + right) analogue cinch audio outputs,
- 2 (input + output) MIDI, and
- 2 (input + output) digital cinch S/PDIF (PCM, AC-3/DTS).
I haven’t worked with digital signals yet, but beyond that everything works perfectly fine.
Latency
A really nice feature of the card is that its latency is very low. You can adjust the buffer size in number of samples from 64 to 4096. Depending on the sample rate the latency can be at most 18/100 of a second (4096 samples at 22.050 kHz) or at least 7/10.000 of a second (64 samples at 96.000 kHz). To be honest, I haven’t tried the least setting yet. Usually I work with 128 samples at 44.100 kHz, which is a latency of 2/100 of a second.
Problems
However, I had some serious issues in the beginning. The card didn’t sound that good when I first tested it. The sound was distorted somehow. A strange high cracking noise was added, which appeared to come from some kind of digital source. It lay above everything which came out and even everything that went in. Recording the input showed the strange noise on the recorded audio. I could see the noise using Audacity to visualise the recorded audio.
First I thought of the latency being to low for my computer to be handled. But trying different settings didn’t work. I got the newest driver from the manufacturer website and searched the internet. There had been other issues with the card but I couldn’t find anyone having the same problem.
At some point the noise started to disappear sometimes. It took me some time to figure out what was causing this effect. Every time my computer was doing some more or less computationally intensive tasks, the noise was gone. This was reproducible using a benchmark tool. When I ran the benchmark the noise was gone, when I stopped it the noise came back. So I thought I must have something to do with the processor.
Solution
After talking to a friend who is more into hardware I played around with some BIOS processor settings. These days there are a number of settings which influence the CPU clock to save power.
The settings which caused my problem was “C-STATE Tech“. Disabling it solved the problem. It’s aim is to save energy when the CPU isn’t doing much calculations. I guess it somehow reduced the CPU clock too much for the audio card to do its job. Or maybe the card is too old to handle features like that. The setting was hidden in my AMI BIOS (v02.61) in “Advanced | CPU Configuration | C-STATE Tech“.
