If you use a USB microphone such as the MiniDSP Umik, you may find a problem with your measured impulse response : the impulse itself is not clean and shows many peaks together instead of just one. This may come from USB problems : gliches or short drop-outs while recording gives such problem. The clock drift itself, coming from a mismatch between player clock and recording clock is compensated by resampling the log sine sweeps thanks to dual chirps at start and end of the audio sequence.
Glitches or drop-outs may be avoided by checking and optimising following parameters :
- remember that the max length of a non-damaged cable is about 3m for USB class 1 (so try with another certified cable)
- in windows configuration/system/advanced parameters : adjust for best performances and activate “background services”
- USB sharing : change USB port and try tu use a port not shared by other components,
- in BIOS, try to modify PCI bridge latency timer (PCIe don’t have latency timers)
- in BIOS, disable CPU throttling
- disable unused sound devices
- disabled all energy saving options and set power plan to max efficiency
- set highest priorities to the recording process
- deactivate temporarelly your antivirus
- some usefull links :
Optimise Audacity and computer
Optimising-your-PC-for-Audio-on-Windows-10
PC-Optimization-Guide-for-Windows-8
Troubleshoot-USB-dropouts-audio-glitches-Windows
Troubleshoot-USB-dropouts-audio-glitches-Mac
AES paper 8169 : Impulse response measurements in the presence of clock drift
And for everything related to audio on computers :