Viewing Issue Advanced Details
ID Category [?] Severity [?] Reproducibility Date Submitted Last Update
06805 Sound Minor Always Dec 26, 2017, 23:10 Dec 28, 2017, 16:50
Tester wuemura View Status Public Platform MAME (Official Binary)
Assigned To Resolution Open OS Windows 10 (64-bit)
Status [?] Confirmed Driver midyunit.cpp
Version 0.192 Fixed in Version Build 64-bit
Summary 06805: narc, narc2, narc3: Annoying high pitch sound
Description Soon after the screen and sound test a high 15 Khz ~ 16 Khz pitch, very sharp beep start to play throughout the game. It looks like one of the channels are out of phase, if you move you head this sharp beep start and stops.
The beep vanishes after you quit the emulation.
Steps To Reproduce
Additional Information
Regression Version
Affected Sets / Systems narc, narc2, narc3
Attached Files
png file icon 20171226_myProject_214341.png (143,616 bytes) Dec 26, 2017, 23:45 Uploaded by wuemura
png file icon harmonics.png (21,855 bytes) Dec 28, 2017, 12:29 Uploaded by wuemura
png file icon harmonics2.png (178,823 bytes) Dec 28, 2017, 12:29 Uploaded by wuemura
zip file icon (75,870 bytes) Dec 28, 2017, 12:31 Uploaded by wuemura
There are no relationship linked to this issue.
User avatar
Dec 27, 2017, 04:54
edited on: Dec 27, 2017, 21:39
If I do recall I believe this is the CVSD channel doing this. Harris 55536.
Update: If you crank up the CVSD volume the noise is there you might need to turn up all the DACS and Yamaha as well.
User avatar
Dec 27, 2017, 08:32
I don't hear it in 0.192 or current GIT.
It could be my cheap headphones and speakers lack the range or I'm just not able to detect that high of a range. Have you experienced versions of MAME where this didn't happen?
User avatar
Dec 27, 2017, 10:09
I've tested with 0.192 and mame0192-771-ge473764e04-dirty, happens on both.
Version 0.140 doesn't have this issue, I could pin point to version 0.145 but it could be earlier since I can't download other versions right now.
That tone is very sharp and loud, tested with a Sony KDL-47W802A that I use as a monitor, Sennheiser HD 800S headphone and a Onkyo HT-S5600.
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Senior Tester
Dec 28, 2017, 03:18
edited on: Dec 28, 2017, 03:22
It's entirely possible the real game does this, and the speakers the cab shipped with weren't good enough to reproduce it.

even with a decent speaker setup here, I can't hear it tho.

there is a very visible DC offset if I look at the output of -wavwrite before coining up however
User avatar
Dec 28, 2017, 03:28
edited on: Dec 28, 2017, 03:28
I think quite a number of the games in MAME that use a lot of channels and chips have this problem like Exidy Mouse Trap.
I have narrowed it down to the CVSD. If you turn down the volume versus other chips it goes away.
User avatar
Dec 28, 2017, 12:33
edited on: Dec 28, 2017, 12:35
Looks like a bunch of odd harmonics.

About the DC Offset, are 9369 on both sides.

    Gain   |  Peak  | Scale | New Peak |Left DC|Right DC| Track
           |        |       |          |Offset | Offset |
  +5.26 dB |  16384 |  1.83 |    30020 | 9369  |  9369  | AUDIO.wav
User avatar
Dec 28, 2017, 16:50
edited on: Dec 28, 2017, 16:50
Most games I have seen with the CVSD have the hissing problem if there are more than three sound devices.

Exidy Mouse Trap
PC Speaker chip but has three channels at one plus noise generator and CVSD chip.

Narc's sound board has the following
 * music: 6809 driving YM2151, DAC
 * effects: 6809 driving CVSD, DAC

The other Williams Games only have (Trog, Smash TV etc) - No audio hiss
 * music&effects : 6809 driving YM2151, DAC, CVSD