Tech: ID4 Sound Issues...

So before I even got this machine, I knew all about the sound issues that later Sega's had where almost all ran in mono and some machines even only had 1 speaker in them. I even read about the missing channel off the soundboard entirely (http://www.pinballnews.com/learn/speaker/).

Anyway, after looking in the head of my ID4, I came to realize that not only do I have 3 audio channels on my board, I also have 3 speakers (sub, left and right) which is good. Now I am thinking about simply upgrading the garbage stock speakers to the Pro Pinball set. I have no problems doing this but my only hesitation is that it seems one of the channels on the sound board is A LOT louder than the other channel. Obnoxiously so. I would hate to upgrade to a nicer speaker set only to still have the balance issues that currently exist.

Also, this obnoxious channel also hums when I hold my right flipper down which suggests to me some sort of grounding issue but I have no idea how to even begin troubleshooting that.

In the pics below, you can see all three channels on the sound board. Mr. Rude channel is on the set of white wires coming out of the molex. I am thinking that the white set and additional caps was added aftermarket and is the culprit. If this is the case, could the prior owner have put on the incorrect caps? I haven't attempted to match numbers or anything since I would probably have to take the board off to get a good look at it. My vision isn't what it used to be.

Any advice is appreciated.

IMG_3158.JPG IMG_3159.JPG

#2 10 years ago

MVM

markmon

Inactive member

Hillsboro, OR

13y 98,300 13,010 21 81

What youre describing is the data east sound platform. Three speakers on three amps.

I'm not sure what the question is. Upgrading the speakers doesn't change the balance of the backbox. If you suspect one of your speakers is bad, simply swap the left and right. If the problem stays with the speaker, its a speaker issue and the pro upgrade will solve it. If not, it won't.

#3 10 years ago

ELF

Elfman

Pinside member

Quoted from markmon:
I'm not sure what the question is. Upgrading the speakers doesn't change the balance of the backbox. If you suspect one of your speakers is bad, simply swap the left and right. If the problem stays with the speaker, its a speaker issue and the pro upgrade will solve it. If not, it won't.

My question is can this balance issue be corrected somehow? I did swap L and R. The over-amplification went to the other speaker so it isn't a speaker issue. This is why I am wondering if I should even invest in the Pro Pinball upgrade. The sound that does come out of the machine will sound better but it will only really be heard out of one side.

Since by all accounts, all the audio was mastered in mono, could I drive both head speakers off of one channel in a series?

#4 10 years ago

MVM

markmon

Inactive member

Hillsboro, OR

13y 98,300 13,010 21 81

OP
Quoted from Elfman:
My question is can this balance issue be corrected somehow? I did swap L and R. The over-amplification went to the other speaker so it isn't a speaker issue. This is why I am wondering if I should even invest in the Pro Pinball upgrade. The sound that does come out of the machine will sound better but it will only really be heard out of one side.
Since by all accounts, all the audio was mastered in mono, could I drive both head speakers off of one channel in a series?

You can if its really mastered in mono. Depending on how much lower the vol is, you could pad the higher vol side with a resistor also.

#5 10 years ago

CMX

viperrwk

Inactive member

Yes, the audio was mastered in mono. You can see that when you play the sounds back in Bridge M1. There are a few legacy sounds in the ROM that are stereo and you can see these in the VU meter - but there are not enough of these to justify this upgrade. The problem is the BSMT2000 is a stereo chip and when it plays back sounds it loads the data from the ROMs into two 8 bit shift registers (74ls165s) which then serially shift the data to a 16 bit stereo TDA1543 DAC. Without knowing how the file is structured, it's difficult to say whether any change to the board would fix the problem.

The cross fader on the pinball pro speaker system will help with separating the lows and highs but not the left and right channels (which don't exist.)

Unfortunately that Pinball News article is misleading at best. This is not at all a worthwhile upgrade. I should know - I did it and added the pinball pro system to my VND.

viperrwk

#6 10 years ago

ELF

Elfman

Pinside member

Thanks Viperrwk. I remember your suggestion from an earlier thread.

So I think I am in for the Pro Pinball upgrade. I am not going to touch the board at all but I would like to try and resolve the balance issue that remains.

Would I be safe to drive the two main speakers in a series off of one channel?

Or should I just splice both speakers into one channel? Can the board handle one channel driving 2 speakers?

Or shall I do what markmon says and get a resistor and put it on the loud channel?

I just want to balance the sound so it is proper mono as opposed to "SCREAMING IN YOUR LEFT EAR" mono. Then use the Pro Pinball upgrade to improve the overall quality of said mono sound.

series.PNG Regular.PNG

_{Post edited by Elfman : grammar}

#7 10 years ago

JGC

dragster73

Jerry Claue

New Baltimore, MI

11y 33,650 81 25

Did you check the volume setting in the adjustment menu?

#8 10 years ago

ELF

Elfman

Pinside member

Quoted from dragster73:
Did you check the volume setting in the adjustment menu?

I have. Only up or down and no L and R. If I unplug the loud speaker, I do get sound out of the other. It is just much quieter.

When the loud channel is unplugged, I can adjust the volume to about 40 - 50%. With Mr. Loudmouth plugged in, I have to set things down to about 20-25% before it gets too loud to listen to.

#9 10 years ago

CMX

viperrwk

Inactive member

Thinking a little more about this and what markmon said, his suggestion might work depending upon how the BSMT2000 is handling the mono file. The problem is lowering the "loud" speaker could wind up lowering resolution because if the BSMT isn't fully replicating the mono sounds on the other channel you'd be making it worse, not better. I've not done enough experimenting with the emulators to see if there's a difference. And even if there isn't, that's not to say there wouldn't be with the actual BSMT since it was designed to play back stereo sounds.

Honestly, since the sounds are mono, disconnecting the other speaker, putting in the PPro system with the crossfader and leaving out the other speaker entirely would be the way I would go. I love the PPro setup. The sub pushes so much air it's almost like a shaker. And spending more money for the second backbox speaker is a waste.

viperrwk

#10 10 years ago

MVM

markmon

Inactive member

Hillsboro, OR

13y 98,300 13,010 21 81

My suggestion is a bit different. Buy the pinball pro sub but don't bother with the backbox. Then wire the two speakers in series (two 4 ohm speakers to 8 ohm load is ok for the amp) and hook that up to the one good amp side. Now the pinball pro comes with a vol control. This is to lower the backbox anyway. Wiring in series and putting these on one amp may already do this enough for you.

You can do that backbox part now without buying pinball pro. Wiring in series:
Left speaker + to amp. Left speaker - to right speaker +. Right speaker - to amp. Amp sees one speaker double the resistance. When this is done, increase the system vol a bit and you should be able to guage it.

Do *not* just wire the two speakers together by twisting the wires or jumping the +/- of one to the other. That will lower the resistance and could blow the onboard amp.

#11 10 years ago

ELF

Elfman

Pinside member

Quoted from markmon:
My suggestion is a bit different. Buy the pinball pro sub but don't bother with the backbox.

Curious as to why you think I wouldn't just upgrade the backbox as well since as far as I can tell, the speakers that are in the machine are stock and sound a bit like coffee filters with wires attached to them. I am new to the hobby and don't mind saving some money too.

Thanks for the feedback on wiring in a series. I believe I captured what you said in the first diagram. I have done this before with my Home Theater seat shakers and it worked perfectly. Please verify it for me though.

Again, appreciate all the feedback!

#12 10 years ago

CMX

viperrwk

Inactive member

Quoted from markmon:
Do *not* just wire the two speakers together by twisting the wires or jumping the +/- of one to the other. That will lower the resistance and could blow the onboard amp.

Yes, totally agree. This would lower the resistance to 2 ohms and that would be bad for the amp. Wiring them in series would make the resistance 8 ohms and the amp can handle that.

Do you want two crappy speakers in the backbox or one good one? It's a tough call between the sounds, cost and performance. If it's a keeper game and you want the best, I'd get the new backbox speaker. If you're not sure, go with what you've got, wire them in series and save the money.

viperrwk

1 week later

#13 10 years ago

ELF

Elfman

Pinside member

So here's the deal. I got my Pinball Pro upgrade today. I installed the system and realized that this system only uses 2 of the three amps that are on the sound board. I still think someone went to the trouble of installing that after market. Since the volume control that comes with the unit then splits the mono to both speakers, annoying speaker problem solved! So not only did I get rid of my annoying channel but now everything sounds simply amazing.

I have to agree with you viperrwk, it is almost shaker-like with how much air the subwoofer moves! Definitely added a little bit of additional value to this table. More than that, it will increase my enjoyment of this table! And that is worth more to me.

#14 10 years ago

ThatGuy

Pinside member

Fresno, CA

11y 40,900 464 4 17

OP
Quoted from Elfman:
So here's the deal. I got my Pinball Pro upgrade today. I installed the system and realized that this system only uses 2 of the three amps that are on the sound board. I still think someone went to the trouble of installing that after market. Since the volume control that comes with the unit then splits the mono to both speakers, annoying speaker problem solved! So not only did I get rid of my annoying channel but now everything sounds simply amazing.
I have to agree with you viperrwk, it is almost shaker-like with how much air the subwoofer moves! Definitely added a little bit of additional value to this table. More than that, it will increase my enjoyment of this table! And that is worth more to me.

Video please!!!

#15 10 years ago

CMX

viperrwk

Inactive member