Problems and Frequently Asked Questions (FAQ)

Note: See the PassMark website (www.passmark.com) for the latest version of the FAQ

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Q. At high sample rates the output audio becomes distorted and "stutters"

This is a known problem with Windows Vista and certain audio drivers. At this point in time the only work around is to lower the sample rate. Rates of 44khz and below should work correctly. If you are experiencing this problem and not using Windows Vista please make sure that you have no other applications running in the background that may degrade your systems performance.

Q. How can I improve the refresh rate, so I can use the real time option without dropping data?

The following actions can be taken to lower the load on the computer and allow a higher refresh rate to be used.

Use a lower sample rate
Use 8bits instead of 16bits
Use mono instead of stereo.
Decrease the size of the SoundCheck window.
Stop any other applications running the background.

To support high data rates you may need to lower the refresh rate instead. Remember 11kHz, 8 bit mono can be processed roughly 16 times quicker than 44kHz, Stereo, 16bits.

Q Why does the Spectrum graph not show higher frequencies?

Higher sample rates also mean that high frequencies can be digitized and displayed on the graph. This is due to the Nyquist theory. Nyquist theory states that a wave form must be sampled twice in order to get a true representation. The maximum frequency value displayed is always half the sample rate.

Q When doing a loopback the input waveform looks nothing like the output. What’s going on?

The input to your sound card is probably being overloaded and clipping high voltages. This will make a sine wave look like a deformed square wave. This is not good for your sound card. Lower the loudness of the sound that you are inputting to the card.

Q I get an error message like, “The sound input device selected is not able to record/playback….”. Why?

Some computers have multiple sound input and output devices. You should check that the correct device (your main sound card) is selected from the Device selection window in SoundCheck. This window can be opened from the Settings menu. The 2nd reason that this error can occur is that the sound format selected is not supported by your sound card. This can happen, for example, when a high sample rate is selected. Most sound cards now support sampling to 44kHz. Top of the line cards may go as high as 96kHz.