BJ229r,
Windows XP comes with a program called "sound recorder" Use this program to open the wav files in the sound folder for Aces High2. You can adjust the volume there and just save it.
Now, I am able to do this for individual sounds and planes because I already use two custom sound packs, USRanger's and HiVolt's Gunpack, so the wav files and plane folders are already there.
If you are using the default game sounds, your sound folder might be empty or just contain a file that says cleaned ( I am not sure). I can't tell you to install custom sound packs, but those two (plus many other very nice sounding) sound packs have added to my enjoyment in playing the game. It will make it easier to adjust the individual plane sounds to levels they were before.
I have a feeling there will be other fixes coming, but I am able to enjoy the new sound system much more after the tweaks to individual planes.
I hope that helps. If you have any more questions you can PM me, as I won't be monitoring the forums as much as I do my messages.
Also, I found this to be very informative:
I apologize for this taking a lot of your screen space. I haven't loaded the new version yet, so I captured and OCR'd the file names of individual sounds from the old version so you can look up the name to create a sound and put in the /sounds directory to use instead of a default (for example making a blank airraid.wav to kill the siren).
Engine: eng.wav
Engine start: engstart.wav
Engine off: engoff.wav
Damage: damage1.wav
Stall horn: stall.wav
Hit sound 1: hit.wav
Hit sound 2: hit_1.wav
Hit sound 3: hit_2.wav
Hit sound 4: hit_3.wav
Hit sound 5: hit_4.wav
Hit sound 6: hit_5.wav
Hit sound 7: hit_6.wav
Tread: tread.wav
Ack: explode2.wav
Small explosion: explode1.wav
Large explosion: explode3.wav
Secondary explosion: explode4.wav
Boat engine: beng.wav
Boat start: bstart.wav
Boat stop: bstop.wav
Wake: wake.wav
Check 6: check6.wav
Jet engine: jeng.wav
Jet start: jstart.wav
Bomb Whistle: whistle.wav
Extern Train: train.wav
Wheel wheel.wav
Air Raid: airraid.wav
Warning: warning.wav
Extern Rocket: reng.wav
Extern Rocket start: rstart.wav
Extern Rocket off: rstop.wav
Rocket engine: reng.wav
Rocket start: rstart.wav
Rocket stop: rstop.wav
Scrape: scrape.wav
Slat: slat.wav
Debris Hit: debris.wav
Vehicle Gas engine: gveng.wav
Vehicle Gas start: gvstart.wav
Vehicle Gas stop: gvstop.wav
Extern Gas Run: gveng.wav
Extern Gas Start: gvstart.wav
Extern Gas Stop: gvstop.wav
Extern Gas Move: wheel.wav
Stall Buffet: buffet.wav
Title Music: tmusic.wav
External Weapon: explode1.wav
Tire Rumble: trumble.wav
Eng Knock: knock1.wav