CAVE PCB sound quality?!?

segasonicfan · Post by **segasonicfan** » Wed Jul 26, 2006 4:01 am

Hey folks,
I just got two beloved Cave games in the mail recently: Dangun Feveron and Esp Ra.De. They are fabulous of course, but I have one minor problem with them. It seems the Cave PCB's have *really* poor audio...or is this just me/my amp??

Esp Ra.De. has a ton of white static noise but both boards suffer from one central audio problem: when there are a ton of explosions occuring or explosions/voice over at the same time there is a sort of staticy pop (looks like it's in the treble range). Has anyone else noticed this?

Just want to make sure it's not something wrong with my equipment. I am doubtful at the moment that it is because my other JAMMA games play great without such problems :/

Any help/info much appreciated!

-Segasonicfan

neorichieb1971 · Post by **neorichieb1971** » Wed Jul 26, 2006 4:06 am

Might be the amp, something touching something else.. could be alot of things. What is your equipment?

Post by **Dave_K.** » Wed Jul 26, 2006 4:15 am

Supergun or cabinet? Do you run the audio out of the jamma board into another amp? 8ohm speaker(s)?

Neon · Post by **Neon** » Wed Jul 26, 2006 4:44 am

Cave PCB's of that era do have crappy sound hardware, but it shouldn't be any worse than in mame.

segasonicfan · Post by **segasonicfan** » Wed Jul 26, 2006 5:40 am

Like I said, I'm pretty sure it's not my equipment b/c all my other JAMMAs work great. But I am running a Supergun through a PVM-2530 amp and into a pair of Infinity speakers. So yeah, the amp is old and not the best quality but the Cave boards still sound much worse than my other stuff. Even my '87 Ajax sounds better :/

Anyone here own Cave boards that can say exactly what the sounds quality should be like?

-Segasonicfan

neorichieb1971 · Post by **neorichieb1971** » Wed Jul 26, 2006 5:56 am

I had ESPra.de and it didn't pop on the trebles like you state.

Maybe try adjusting the volume control on the PCB. Maybe the PSU is overpowering the amp slightly by a smidgen of a volt or something.

segasonicfan · Post by **segasonicfan** » Wed Jul 26, 2006 6:47 am

hrmmm...it does have the terrible white noice (especially on startup) though, right?

-Segasonicfan

neorichieb1971 · Post by **neorichieb1971** » Wed Jul 26, 2006 6:56 am

White noise as in a high pitch squeal?

I think most electronics do that. Most normal amps/receivers have a temp cutoff before they power up to cover up this.. Thats why you hear a click after about 2 seconds when the audio circuitry is reconnected to the outputs.

I doubt this has anything to do with ingame audio. I take it your getting this problem throughout the gameplay and intro etc?

Clean the contacts of the pcb. Try moving the volume control on the PCB to a different position.. dirt and grime inside there might be causing a connection issue. But to me it sounds like an over power of the amp or a ground issue.

It could even be that someone else before you over powered the amp and what your hearing is a side effect.

D · Post by D » Wed Jul 26, 2006 9:13 am

Audio can only be so loud. At a certain point when an audio signal is so loud of the wire, the signal can become distorted once it reaches the amplifier of the cabinet/supergun.

When the volume is too low then hizz becomes more notable.
Try and find a balance, might it just be your setup instead of the pcb?

Post by **system11** » Wed Jul 26, 2006 9:24 am

I'm afraid it's normal for the boards. The one with more background noise possibly has a grounding or filter caps issue, but it's nothing to worry about unless you're getting a constant loud noise even when in test mode.

Trouble with Cave audio on that age of board, is everything is hugely downsampled. It's got no definition at all really, and neither the amp nor your average full range speaker can cope with the distorted over-amped mess that results.

Classic run before you can walk issue. They should have gone with sequenced audio until bigger eproms were available.

raiden · Post by **raiden** » Wed Jul 26, 2006 4:29 pm

I´d try removing the amp to see what happens. Most Jamma boards have an amp section on board anyway, and using an additional amp might even hurt your boards in the long run.

Post by **system11** » Wed Jul 26, 2006 4:55 pm

What are you using to play these on?

segasonicfan · Post by **segasonicfan** » Wed Jul 26, 2006 8:51 pm

I´d try removing the amp to see what happens. Most Jamma boards have an amp section on board anyway, and using an additional amp might even hurt your boards in the long run.

I tried pulling the audio directly from the volume pot before it goes to the amp on my Dangun Feveron. but the little sound problems are still there. Like I said, this isn't huge stuff, so I think (and I'm hoping) it's what Bloodflowers is saying- these boards just don't have the higest audio quality. Dangun sounds great except when too many explosions are going on and such it gets a little bit crackly.

After playing Esprade some more it doesn't seem to have any of the crackly sounds Dangun gets, really the only problem is the white noise on startup. However, my setup is probably adding to that since I'm using a PVM-2530 and the amps in those are pretty dated.

-Segasonicfan

Post by **Dave_K.** » Wed Jul 26, 2006 8:53 pm

segasonicfan wrote:Like I said, I'm pretty sure it's not my equipment b/c all my other JAMMAs work great. But I am running a Supergun through a PVM-2530 amp and into a pair of Infinity speakers. So yeah, the amp is old and not the best quality but the Cave boards still sound much worse than my other stuff. Even my '87 Ajax sounds better :/

Do you have a good supergun which uses a dummy load to attenuate the sound for an external amp? If not, this will screw with your frequency response if you try to go straight to an amp. Make sure the sound pot on the PCB is turned down almost as far as it can go.

segasonicfan wrote: Anyone here own Cave boards that can say exactly what the sounds quality should be like?

Well if it wasn't for the damn heat, you'd be able to hear it at the next bay area shmupmeet. Probably not going to have one now till September.

Post by **system11** » Wed Jul 26, 2006 9:40 pm

You know, I've been thinking for a while, of creating a thread listing common issues with certain games or hardware types. Maybe I'll start work on it now. The Guwange I had sounded /really/ bad when I got it, replaced the caps which improved the strength of the sound, but it was still a horrible downsampled mess

Then you've got Raiden II - voltage/sprites, Konami Nemesis hardware with voltage/death, a certain type of op-amp on some Taito games from the Plotting era commonly dies and takes most of the sound away - stuff like that. Kaneko Supernova boards are known for a cap which wears out, leading to crackly distortion when the game warms up (later ones have an extra helper cap soldered under the PCB).

The list goes on.

PC Engine Fan X! · Post by **PC Engine Fan X!** » Thu Jul 27, 2006 12:52 am

For Bloodflowers,

What is this Seibu Kaihatsu Raiden II PCB issue of voltage/sprites problem?

Please elaborate. ^_~

PC Engine Fan X! ^_~

segasonicfan · Post by **segasonicfan** » Thu Jul 27, 2006 9:01 am

Bloodflowers- That sounds like a really good idea, that information would be helpful to many people I am sure! As for your Guwange, could you tell me which caps you replaced? It would be easy for me to replace caps on my Cave boards to help the sounds quality

-Segasonicfan

Post by **system11** » Thu Jul 27, 2006 9:09 am

segasonicfan wrote:Bloodflowers- That sounds like a really good idea, that information would be helpful to many people I am sure! As for your Guwange, could you tell me which caps you replaced? It would be easy for me to replace caps on my Cave boards to help the sounds quality

I'm afraid it wasn't very scientific - I did all of them near the amp.

PC Engine: Raiden II, if the voltage is too low or high (I can't remember which offhand), sometimes the sprites flicker like the board is faulty.

dpful · Post by **dpful** » Thu Jul 27, 2006 2:28 pm

Confirm, those cave games have horrible sound quality. Hardware is fine, sample rate is really low so they always sound a bit fuzzy.
If you EQ the signal, you can bring out the best of it and hide the worst of it (which is why it may sound better in mame if you've got nice speakers).

segasonicfan · Post by **segasonicfan** » Fri Jul 28, 2006 1:23 am

Confirm, those cave games have horrible sound quality. Hardware is fine, sample rate is really low so they always sound a bit fuzzy.
If you EQ the signal, you can bring out the best of it and hide the worst of it (which is why it may sound better in mame if you've got nice speakers).

Ah I see! Thanks so much for confirming this. I did notice the sound was much better when I connected speakers directly to it instead of going through the ancient PVM amp- that's what is accounting for the white noise I believe (low S/N ratio is my guess). But it's good to know my boards aren't damaged all, though I will likely replace the caps like bloodflowers did.

Also, I noticed they're using an ANCIENT amp for the audio- the LA4460N. This is on some of my oldest JAMMA boards..lol. Pin 2 of the amp is audio input (coming from the VR) so I imagine if the audio is tapped pre-amp and pre-pot it will sound a little better. Though you are right, the sample rate is still pretty low.

Thanks so much for the info guys, I really appreciate it!

-Segasonicfan

segasonicfan · Post by **segasonicfan** » Mon Jul 31, 2006 10:56 am

Important update(s):

I brought my board over to Dave K's place on Saturday for the shmupmeet so he could tell me if the sound on my board was abnormal. Fortunately it's as people have been saying- just poor sound quality on those boards, nothing wrong with mine in peticular.

However, I just tried Dangun Feveron on MAME and the sound is perfect

So what does this mean? Well, I'm hoping I can extract the audio from some pre-amp place on the board for perfect sound quality. I tried drawing it from the pot before it reaches the LA4460N but the quality seemed the same. My next best guess is to draw it before the National circuit which I believe is an opamp? Gotta check that.

Most of you probably don't care about it at this point, but Cave games have some of my favorite audio and this is just one area where I am damn anal about quality

-Segasonicfan

neorichieb1971 · Post by **neorichieb1971** » Mon Jul 31, 2006 11:01 am

My ESP.rade didnt sound bad at all.. Sounded perfect to me.

If MAME is getting perfect sound on Cave games, it means somewhere along the line your audio quality went south.

segasonicfan · Post by **segasonicfan** » Mon Jul 31, 2006 2:00 pm

My ESP.rade didnt sound bad at all.. Sounded perfect to me.

If MAME is getting perfect sound on Cave games, it means somewhere along the line your audio quality went south.

Esprade's audio is a lot better than Dangun's. Id doesn't have the scratchy announcer vocals.

and just to clarify: The audio works fine in these games, these are only problems that concern audiophiles. For the common gamer the normal sound quality will suffice.

-Segasonicfan

RFL · Post by **RFL** » Fri Aug 11, 2006 2:45 pm

My ESP.Ra.De. sounded just fine, I think... I had som "static" or "white" noise, yes, but that was mainly my cab making those noises... I can really agree when it comes to sound quality on older Cave boards... I have owned DoDonPachi and ESP.Ra.De. and the music and effect sounds kind of cheap... When I think about it, it's nothing I noticed back then, it's only after owning newer games that it struck me...

shmups.system11.org

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