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I was a huge Asteroids fan when I was a kid. (Well, I was a normal-sized kid but I REALLY loved Asteroids. wink ) Anyway, it's been interesting to see how sound in MAME's Asteroids has evolved. When they did away with the samples, and started emulating the sound, it was pretty rough for a while. Now, it's pretty darn good.... with one glaring exception: the pitch of the "thumps" is incorrect. (The thumps are the low notes that alternate faster and faster as asteroids become fewer.)

I'll put this musically, since it's the only way I know how.... Currently, MAME has the interval between the two thumps as a major third. They should actually be a minor second.

I obtained the following samples from Vectorama, a lovely OS9 vector game emulator many of you no doubt remember. These are the thumps in their proper pitch as recorded from an actual Asteroids cabinet.


The Asteroid samples in this emulator were the best I've heard, so I pulled them out with ResEdit and hung on to them. The rest of them can be browsed here:


I just wanted to share my thoughts with all of you and ask for your recommendation. Who on the MAME development team would A) be interested in hearing such a comment and B) have the programming skills necessary to do something about it?

Boy, I wish I had these samples to listen to when I wrote Shoot Things...
At one time Asteroids did use sound samples. I dont know how far back in version numbers you would have to go (definitely before the switch to the new numbering scheme). Let alone where you would find ROMs that would work with a version that old. But it could be done.

I am half suprised nobody has released a sub-version of MAME that incorporates the old Asteroids sample code.
The roms for asteroids haven't changed in eons have they?

Getting roms for an old version of asteroids is not liklely to be a problem though. I have 8 Asteroids boards on the shelf and I know plenty of other people have similar numbers.

Very common game. if it needed to be redumped, then it wouldn't be hard.
Chris: If you post over at MAMETesters.org it's likely Derrick Renaud (the discrete audio guru) would see it. Be warned: the current pitch is set according to Atari's schematics, and you are attempting to prove that Atari misprinted them. That's not actually uncommon - the Pong schematics have multiple errors - but it's still sort of a tough thing. (A picture of the relevant resistors/capacitors from a working PCB would suffice).

ETA: Also it's possible (actually likely given how often Brad updates it) MacMAME doesn't have the latest fixes. Try it on 100u2 on a PC for best verification.

ETA2: It's possible the pitch is controlled by a variable resistor on the board. In that case, press ~ and adjust the various discrete component values until you get the correct sound and report those values @ MAMETesters.
Nice domain name... laugh
The pitch is not adjusted by a variable resistor...

The only variable resistors on the board are for X & Y gain.

I can help out with values of components if someone tells me which one's they're after.

It's highly likely that:

1) the schematics could be wrong (they are a bit of a mess for Asteroids!)
2) there are known to be more than one revision of Asteroids boards, even slightly different component layouts. It's possible that could account for the difference? (Have been reinstalling OSX so haven't listened to the clips yet).
3) Umm, there was a 3, but someone was talking to me while I was writing this so I've completely forgotten it smile

I'm sure I'll remember it sometime soon!

If I can help, let me know. There is also full Asteroids source code on my website (http://www.guddler.co.uk) - partially commented (not by me).

Thank you all for the very informative replies. I will install the latest Mame32 on my wife's Windows XP laptop (EW! wink ) and listen to the thumps.

My take on the pitches comes from my musical background. My father is a music professor at a California State University. I grew up with a piano and lessons in various instruments. I remember playing the thumps on my piano! LOL... ...and even reproducing many of the sounds on one of the analog synthesizers at the college's music department. (Fairly accurately if I do say so myself.) smile I can say with almost absolute certainty that the interval between the thumps was a minor second (A half-step on a piano keyboard) on every Asteroids game I ever played... and I played every single one my parents let me. :-) As a kid I was always fascinated by the quality of certain intervals. Most doorbells are either a major third or a minor third. I like the one at our house because it was a major third; it's happier sounding. Minor thirds are morose and troubled. (I know... I'm a weirdo.) I distinctly remember taking note of the minor second interval in Asteroids and being fascinated by the nerve-wracking suspense it induced. The major third interval in MAME's Asteroids is like a happy doorbell; it just doesn't fit at all.

I don't know what the Asteroids thump notes actually were. (I'm not lucky enough to have perfect pitch.) But when I hear the Vectorama samples, that nails it better than anything I've ever heard anywhere else.

It also seems like to me that MAME's Asteroid sounds are much warmer than that of the real game. The arcade cabinet blurted out harsh square and sawtooth waves. That edgy, stabbing quality seems somewhat smoothed out in emulation.

I shall take the advice of R. Belmont and cross post my original post to MAMETesters.org and see what folks have to say. I'll report back any interesting progress. I wonder if my musical sensibilities would carry any weight when the schematics seem to tell a different story.

Thanks again....
I agree with you, Chris. The real machine was definitely playing a minor second, which I always think of as a tense, stressful interval. A major third is happy, which makes the game feel wrong.

I agree with you about doorbells, too :-)
The harshness will also be contributed to by the degradation of the resistance in the cabinet's ground's over time. Probably to a certain degree even "back in the day", but definately more prominent on machines now.

This causes all sorts of problems with age, but harsh sometimes crackly noises is definately one symptom.
I posted a message to

It hasn't shown up yet. I don't know if I have to wait for a moderator to approve the post or if I did something incorrect when I posted it. I don't want to re-post it; I don't want anyone bent out of shape at the "newbie." smile So I'm just going to wait a couple days and see what happens.

It should show up right away - if it didn't, you didn't do it right. Keep in mind that when you first click post on that software it *always* goes into preview and you have to click post again for it to actually go.
R. Belmot wrote:
> It should show up right away - if it didn't, you
> didn't do it right.

Okay... Thanks for the info. I'll attempt to post it again soon. For now it looks like there's an issue with the message board. It's currently displaying a "This Account Has Been Suspended" message.

Well... Here's the thread:


It was moved to "MAME chat" by a moderator. It sounds like I have a tough case to prove. I don't own an Asteroids PCB nor any of the equipment necessary to test it. I know a couple of people who have Asteroids cabinets. I don't think I could get them to participate in any PCB testing, but I might be able to talk them into recording game play to demonstrate the frequency of the thumps.

Anyway.... If anyone wishes to participate in the thread, feel free to chime in on the URL above. And thanks again for the feedback.

-Chris Johnson
Well, as I've already said, I have Asteroids boards (and a cab) and plenty of test gear. Let me know what tests you want doing and I can let you know if I can do them for you.

What I'm not overly keen on is signing up to yet another forum in order to participate in a thread. I have enough trouble keeping track of all the forums in life as it is smile

As an aside, are you talking about the interval between the thumps, or the "highness" (or "lowness"!) of the thumps themselves.

If it's the latter then surely another thing that would effect it would be the size of the speaker used, and the acoustics of the cab it's in. Put simpler, a cabaret would sound different to an upright to a cocktail, to a bootleg, wouldn't it?

Oh, and the shielding of the speaker. My cabaret has a metal shroud over the speaker for instance. That would make it sound different to one without.

Surely things like this can't realistically be expected to be emulated rightly or wrongly?
Originally posted by Martin:
If it's the latter then surely another thing that would effect it would be the size of the speaker used, and the acoustics of the cab it's in. Put simpler, a cabaret would sound different to an upright to a cocktail, to a bootleg, wouldn't it?

Oh, and the shielding of the speaker. My cabaret has a metal shroud over the speaker for instance. That would make it sound different to one without.
perhaps different harmonics are being emphasised with these variables in the sound systems?
As a guy WITH perfect pitch...

If a note is OFF. It's freaking off, and no amount of harmonics, speaker and cab sizes are going to change that... it would be down to an emulation issue.

I don't know enough about the original asteroids machine, but I'm dang sure if I ever HAD heard an original, I'd be able to tell the difference between incorrect emulation and simple cabinet differences. In fact... even moreso than Mr. Johnson, it would drive me absolutely crazy.

To sum up... I'm glad I never paid much attention to the machine when it was in arcades.
Best you be glad you haven't got one then - LOL!!
Martin wrote:
> As an aside, are you talking about the interval
> between the thumps, or the "highness" (or
> "lowness"!) of the thumps themselves.

When I say "interval" I'm talking about a musical interval , rather than a time interval.

If I had perfect pitch , I'd actually be able to remember what the pitch of the thumps actually was. Unfortunately, I'm not as lucky as mahuti. smile However, I do have enough musical training and ability to be able to identify the distance between two notes, and I definitely remember them being a minor second . And what mahuti said is dead on. If the notes are wrong, they're wrong. The size of the speaker enclosure or the materials used around the speaker might color the tone by emphasizing certain harmonics or overtones . It would not actually change the pitch of the note coming out of the speaker.

I don't know exactly what needs to be done to satisfy the key MAME developers that the pitch needs to be corrected, but if you wouldn't mind volunteering your expertise, I'll do my best to find out what needs to be done and let you know. And if it's something that's in your realm of abilities and time-availability, it'd be GREAT to get it fixed finally. It's been bugging me for a long time!

I'll keep y'all posted....

-Chris Johnson
Well, the best approach (in my uneducated opinion) would be to get some good quality recording gear, and make a digital recording of the sounds through the cabinet's speaker. (Making sure the speaker is in good condition.) You could, I suppose, adapt the signal going into the speaker to the input of the recorder, to bypass the speaker entirely.

Then, use something like SnapzPro to rip the audio from MacMAME's version of Asteroids, throw the two tracks into some audio analyzing software, and compare them.

The key though, is starting out with an Asteroids machine that's in good working order. If you don't have that, the rest of the comparison is meaningless.
Well, I'm hoping that Derrick Renaud will eventually see the thread I started over at mameworld.info. Martin, I took the liberty of mentioning that I knew of someone with Asteroids hardware that would be willing to perform some testing. Let's hope that Derrick sees it and it winds up on his to-do list.

I'll check periodically and keep you posted.

-Chris Johnson
No problem - in the meantime I'll take a peek at the code when I get a moment and see if I understand how the analogue side of it is being emulated.

If I do then I can double check the values against the boards that I have access to, primarily to see if they are different across multiple boards and if they are all the same, if they match that of the emulation.

I guess that would be a good first step to see if we agree with the emulation before jumping on to whether the sound the emulation is producing should be different or not.

I think that makes sence! I've not looked at the source yet and could be way off in my understanding of what needs to be done / looked at!

PS: Thanks for the explanation on the interval! Not being overly musical that was confusing smile
[sigh] if only I had..perfect pitch !
I noticed the following on the list of updates for MAME.102

"Updated the discrete thump sound in Asteroids to use component values instead of derived equations. [Hans Andersson, Derrick Renaud]"


Since my main computer is a Mac, it took me a few days to get the Mame32 .102 version installed on my windows PEEcee at work. But I finally did today. AND THEY FIXED IT! HOORAY!!!! The thumps sound fantastic. Hans Andersson and/or Derrick Renaud must've seen the thread I started over at mameworld.info . I am just totally jazzed. Many thanks to everyone here for the advice and insight.

-Chris Johnson
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