Originally Posted by: Slash333333 
Same problem. Static in the audio, which seems to vary slightly with game load. Almost feels like a PCI-Express bandwidth hogging issue, but I haven't attempted to diagnose it further. I'm curious if limiting the graphics to 30FPS would alleviate the issue, but not curious enough to sit through another ten minute demo intro...
I also have a Creative X-Fi Titanium Fatal1ty PCI-E sound card, selecting a few different output modes did nothing to change the situation. Creative driver 6.0.240.15
Windows 10 Pro build 1709
ASRock Z77 Formula OC
i7-2600K @ 4.4GHz
32GB 2133MHz DDR3
Gigabyte G1 Gaming GeForce GTX 1080 @ Stock Clocks, 90% Power Limit and on driver 399.24
RAID 0 SATA SSDs, blah blah blah.
Mostly wanted to post here to let others know that it's not just them. I do not own any previous Forza products on PC and haven't encountered a similar audio corruption problem with any other recent PC games that I can recall.
Just as a follow up, I did reload the game and attempted a variety of fixes, none of which worked.
· Disabled Audio Enhancements
· Tried different bit rates, from 16/44.1kHz through 32/96kHz.
· Tried 2/2.1 speaker output, as well as 4/4.1 speaker output, and back to the typical 5.1 speaker output.
· Limited game to 20FPS, 30FPS and set to Very Low detail to eliminate GPU stressor & PCI-E traffic.
· Limited process to Very Low priority.
· Limited process to 1, 2 and 4 logical cores (vs 8).
· Tried windowed mode vs full screen mode.
· Disabled GPU resolution scaling.
· Disabled CPU processor state downclocking (minimum proc state 100% in adv power management)
It has to be something within the game's audio engine or the DirectAudio layer, whether the issue is with the game or with the way the X-Fi's drivers process the resulting audio I'm not sure. Any and all sound being played in parallel to FH4's staticky audio is played back with no issues whatsoever. I can run Winamp, MPC, watch Youtube videos or run a second game and the only audio being distorted is that of the Forza Horizon 4 demo. In thinking back, I want to say that the benchmark for Final Fantasy XV also had similar corrupted audio output, but I only briefly played around with that and never followed up or played the full game. Some light Googling left me relatively empty handed, aside from the prospect of trying one or two other driver sets, and since FH4 is the only problem I'm loathe to consider that.
Dunno. Hope someone at Turn 10 has an X-Fi...it's definitely a problem. If they want I'll mail them mine.