(Topic ID: 330177)

Space Invaders Sound Question

By Dan_Halen

1 year ago



Topic Stats

  • 6 posts
  • 3 Pinsiders participating
  • Latest reply 18 days ago by Quench
  • Topic is favorited by 1 Pinsider

You

Linked Games

#1 1 year ago

Hi All!

I've gotten myself a slightly used Space Invaders pin and had a general audio question.

The overall volume is controlled just fine with the potentiometer that is on the board, but the jarring noise that plays when the right drop target starts flashing does not seem to be affected by this control. Is there a different pot that I'm failing to find? If not, is there a way that I can put a pot in line somewhere to make this controllable down the road?

The game does have a new Altek MPU, so I don't know if that helps or hurts in this situation at all, just thought I'd add that in there.

Thank you!

#2 1 year ago
Quoted from Dan_Halen:

Is there a different pot that I'm failing to find? If not, is there a way that I can put a pot in line somewhere to make this controllable down the road?

The invader siren sound is generated like all other sounds via the AY-3-8910 programmable sound generator chip at U1.
It's been some time since I looked at the datasheet but from memory, sounds can be individually (programmed) at different volumes. So it's likely that sound is set to maximum while other sounds are set lower.
The chip has three separate audio outputs that can be programmed to play different sounds. Unfortunately that invader siren is on the same output pin as other sounds so you can't externally control it alone using a pot without affecting other sounds.
It requires a software mod to reduce the volume on that effect only.

#3 1 year ago
Quoted from Quench:

The invader siren sound is generated like all other sounds via the AY-3-8910 programmable sound generator chip at U1.
It's been some time since I looked at the datasheet but from memory sounds can be individually (programmed) at different volumes. So it's likely that sound is set to maximum while other sounds are set lower.
The chip has three separate audio outputs that can be programmed to play different sounds. Unfortunately that invader siren is on the same output pin as other sounds so you can't externally control it alone using a pot without affecting other sounds.
It requires a software mod to reduce the volume on that effect only.

Thank you for the very informed answer. I’m learning a lot about these old Bally machines and I’m sure at least a chunk will transfer over to the Embryon machine that’s coming.

I guess now I gotta learn how to program new ROMS

#4 1 year ago
Quoted from Dan_Halen:

I guess now I gotta learn how to program new ROMS

In the sound ROM, the volume info for that sound effect is at hex offset $0717
The hex value $0F there is max volume. Lower it to something like $0A to reduce the volume of that sound effect.

1 year later
#5 19 days ago

I wanted to give an update to this thread as I too always found that siren sound set at an obnoxious level.

With the suggestions given here from Quench I reached out to HobbyRoms to get a ROM burned since I don't have a ROM Burner.
https://www.hobbyroms.com/

HobbyRoms burned the EPROM for me (it is the one in location U4 not U1) with the value hex offset $0717 set to $0A (10 down from the initial 15).

I think it is the perfect balance. The volume is no longer at a jarring level and because of the frequency of the siren, the sound still cuts through.

Thank you Quench and HobbyRoms for your help!

-Robert

#6 18 days ago
Quoted from spaceport:

The volume is no longer at a jarring level and because of the frequency of the siren, the sound still cuts through.

Thankyou for confirming the adjustment, you're the first to provide any feedback.

Promoted items from Pinside Marketplace and Pinside Shops!
From: $ 1.00
Playfield - Other
Rocket City Pinball
 
$ 9.00
Cabinet Parts
Third Coast Pinball
 
$ 30.00
Lighting - Led
Pinballrom
 
$ 69.00
Gameroom - Decorations
Pinball Pimp
 
$ 18.00
Electronics
Yorktown Arcade Supply
 
$ 9.95
Eproms
Pinballrom
 
$ 10.00
Playfield - Decals
Metal-Mods
 
From: $ 170.00
$ 69.00
Gameroom - Decorations
Pinball Pimp
 
From: $ 14.00
Electronics
Third Coast Pinball
 
$ 10.00
$ 5.95
Playfield - Protection
The Pinball Scientist
 
$ 18.95
Eproms
Pinballrom
 
Great pinball charity
Pinball Edu

Reply

Wanna join the discussion? Please sign in to reply to this topic.

Hey there! Welcome to Pinside!

Donate to Pinside

Great to see you're enjoying Pinside! Did you know Pinside is able to run without any 3rd-party banners or ads, thanks to the support from our visitors? Please consider a donation to Pinside and get anext to your username to show for it! Or better yet, subscribe to Pinside+!


This page was printed from and we tried optimising it for printing. Some page elements may have been deliberately hidden.

Scan the QR code on the left to jump to the URL this document was printed from.