Thanks Matt, Dan, and Musocity. The feedback and suggestions you've made were tried before posting, but I still appreciate your replies. Matt, I tried every buffer setting my interface would allow. No joy. I have 8 cores and 32GB of ram, SSD disk. It's a mean and fast machine.

There's some good news:
The BIOS has three options for HD audio: Disabled, Enabled, and Auto. I set it to "Auto" and booted into Windows. I did not install the Realtek audio drivers this time. After telling BIAB to use the "Headphones" (front jack) and not the "Speakers" (back panel) which appeared in my sound control panel and plugging a headphone cable into the front panel connector, problem solved! BIAB playback is clean. ASIO, WAS, MME = clean. 41k or 44K = clean. Time to set this thread to resolved.

Going forward it seems there are two lessons learned: 1) still don't understand why BIAB expects the internal audio hardware to be present and corrupts the playback if it's not there. Has PG Music ever tried to recreate this issue? Does BIAB play cleanly on other PCs that have motherboard audio disabled? 2) Don't install the Realtek drivers that came with the MB, BIAB won't play cleanly if they're installed. Windows 11 uses it's own drivers and the Realtek drivers aren't needed.

Last edited by SaxaBruce; 02/25/24 10:10 PM. Reason: added more detail
Bruce Hook - Soprano, Alto and Tenor Saxes
BIAB 2023 UltraPak | Intel i7 | Mackie ProFX10v3 Audio Interface | 1TB SSD | Reaper DAW
| Akai EWI 5000 | M-Audio Oxygen Pro 49