Game Sounds
You may customize your sounds for each aircraft, vehicle and boat in Aces High II.  To change sound volume, click Options->Preferences->Game Sounds from the clipboard menu.  
Aces High II Sound Control PanelTo change a sound volume, click on an item in the list and use the slider to adjust the volume to your personal preference.

The way Aces High II is designed is to look first for a custom sound, and if one is not found, use the default sound from the ../HTC/Aces High II/sounds directory. 

Custom sounds can be added by creating named subdirectories in your ../HTC/Aces High II/sounds/ directory, then adding the .wav files with the appropriate file name.  The correct file names are displayed in the Sounds dialog.

The subdirectory names for custom sounds are as follows:

Model Subdirectory name
A-20G a20g
A6M2 a6m2
A6M5b a6m5b
Ar 234 ar234
B-17G b17g
B-24J b24j
B-26B b26b
B5N2 b5n2
Bf 109E-4 109e4
Bf 109F-4 109f4
Bf 109G-2 109g2
Bf 109G-6 109g6
Bf 109G-14 109g14
Bf 109K-4 109k4
Bf 110C-4b 110c4
Bf 110G-2 110g2
Boston III boston3
C-47A c47a
C.202 c202
C.205 c205
D3A1 d3a1
F4F-4 f4f4
F4U-1 f4u1
F4U-1C f4u1c
F4U-1D f4u1d
F4U-4 f4u4
F6F-5 f6f5
FM2 fm2
Fw 190A-5 190a5
Fw 190A-8 190a8
Fw 190D-9 190d9
Fw 190F-8 190f8
Hurricane Mk I hurri1
Hurricane Mk IIC hurri2c
Hurricane Mk IID hurri2d
Il-2 Type 3 il23
Ju 87D-3 ju87d3
Ju 88A-4 ju88a4
Ki-61-I-KAIc ki611c
Ki-67 ki67
La-5FN la5fn
La-7 la7
Lancaster III lanc3
LVTA2 lvta2
LVTA4 lvta4
M-16 MGMC m16
M-3 m3
M-8 m8
Me 163B me163
Me 262A-1 me262
Mosquito Mk VI mossie6
N1K2-J n1k2
Ostwind ostwind
P-38G p38g
P-38J p38j
P-38L p38l
P-40B p40b
P-40E p40e
P-47D-11 p47d11
P-47D-25 p47d25
P-47D-40 p47d40
P-47N P-47N
P-51B p51b
P-51D p51d
Panzer IV H panzr4h
PT Boat ptboat
SBD-5 sbd5
Seafire Mk IIc seafire
Spitfire Mk I spit1
Spitfire Mk V spit5
Spitfire Mk VIII spit8
Spitfire Mk IX spit9
Spitfire Mk XIV spit14
Spitfire Mk XVI spit16
T-34 t341943
Ta 152H-1 ta152h
TBM-3 tbm3
Tempest tempest
Tiger I tiger1
Typhoon typhoon
Yak-9T yak9t
Yak-9U yak9u

If, for example, you wanted to change the engine sound for the F4U-1D, you would make a new folder in your ../HTC/Aces High II/sounds directory and name the folder f4u1d.  Next, you would place your new engine sound .wav file into the f4u1d folder and name it eng.wav.