What are usual maximum output frequencies on computer sound cards?

What are usual maximum output frequencies on computer sound cards?

• Exactly what it says on the tin. I have a Sound Blaster X-Fi Xtreme Audio Notebook sound card and I was measuring its output frequency using frequency counter connected to the card's output. Frequency was generated using a program called FrequencyGenerator. I've noticed that it can't provide frequencies higher than 16 kHz (upper limit of audible range is at 20 kHz) and I found that strange. Is there any info on common maximum frequencies provided by sound cards? I know that for example Realtek ALC 268 can provide as much as 19500 Hz (which is pretty close to the needed 20 kHz), but since X-Fi is supposed to be better than average integrated sound card, is are ALC 268's capabilities an exception or is the X-Fi just really bad card (as in has low output spectrum)?

• Answer:

  Here's http://audio.rightmark.org/downloads/Sound%20Blaster%20X-Fi%20Testing%20Methodology%20And%20Results%20For%20RMAA%20v5.5.pdf (PDF) for the X-FI. On page 15, their results using a loopback (output cable plugged into line-in and recording) indicate a relatively even frequency response up until 20khz and beyond. This testing technique has the advantage of excluding the speaker from the testing, but the drawback is being limited on the input capabilities, which can have lower specs. The X-FI is http://www.creative.com/soundblaster/products/musicmovies/article.asp?articleID=53937&categoryID=15 for both playback and recording at 24bit/96khz Don't forget that MP3s are stripped of frequency range above 16khz so that is not a test source to use. Ideally, use a software sine wave generator.