MPU-401/AT Plays both SCB-55 and MT-32 that attach to it PIC

[Mike 01Hawk]

So... FINALLY the midi adapter/cables came in the mail today
Anyway, here's my little set up:

Sorry for the big pic (1024x768)


MT-32
Input:
Off the MPU-401/AT MIDI OUT is a Mini-DIN to Full-DIN adapter -> 1ft MIDI cable -> IN on the MT-32

Output:
Phono to RCA Adapters -> 2RCA to 3.5mm Plug -> 1st leg of a 3.5mm Splitter -> Line in on the SB16

SCB-55
Input:
Internally connected to the MPU-401/AT waveblaster header

Output:
A horrifically long 3.5mm patch cable -> 2nd leg of a 3.5mm Splitter -> Line in on the SB16

What you don't see in the pic is the 12ft 3.5mm patch cable to my Logitech Z-5500 speakers.

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So, power on the MT-32, fire up the machine, go into Lands of Lore Setup and select MT-32.  Load up the game and tada!!! I've got Sysex messages a flying, and I've got SOUND!  Then just to make sure it's not the SCB-55 playing, I turn off the MT-32..... annnd... STILL HAVE MUSIC PLAYING!!! :x No wonder people don't get all hot to trot about older pc setups, talk about a never ending pain!

So yeah, guess the music is going to both the MT-32 AND the SCB-55 and I have to physically remove the 3.5mm that I don't want to hear from the Splitter.

So... please tell me there is a software work around to this, don't make me have to physically remove the cables all the time or get a switch like the one that was alluded to in another thread

If a switch is a must have, what's a good cheap one?

One last question, the MT-32 calls for 9v 650mA and right now it's being powered by a Radio Smack 9v 800mA.  Should I play it safe and get a 650mA?  If so, please point me in the direction of one.

[HondaSiR]

One last question, the MT-32 calls for 9v 650mA and right now it's being powered by a Radio Smack 9v 800mA.  Should I play it safe and get a 650mA?

Your current 800mA adaptor is fine. It should be a problem if it falls below 650mA as the adaptor may overheat. I currently use a 9v 1200mA for my CM-500 and MT-32 with no problems whatsoever (I use them one at a time).

[Ari]

Honda answered your question regarding the power supply.
As for both MT-32 and SCB-55 playing simultaneously, I use an audio/video switch such as this to choose between my SCB-55, LAPC-I and Yamaha SW60XG cards. Works like a charm for me.

[Cloudschatze]

In addition to Ari's mention, here are a couple of small, and relatively inexpensive audio mixers:

Roland MX-5
Boss BX-4
MidiMan Multimixer 10


Your "splitter" looks exactly like a 1/8" dual-mono to 1/8" stereo adapter, by-the-way...

[Great Hierophant]

I will definitely need a switch for my audio setup:
Roland LAPC-I
Roland MPU-401AT + SCB-55
Roland MT-32 (when I get one)
Sound Blaster 16
Aureal SQ2500

[Mike 01Hawk]

So sending signals to both the waveblaster AND the MIDI Out is just the way the MPU-401/AT was designed?

Oh and Cloud... splitter/adapter.. meh!!! :wink:

It was listed as a Stereo cord, so.. need to test out all that left/right stuff w/ the MT-32 and the SCB-55 next chance I get.

[Ari]

It's like that with all soundcards with Waveblaster connectors, AFAIK.
To do it any other way, a sound card would need to use 2 distinct I/O ports since thats how the MIDI data gets transfered.

[Mike 01Hawk]

Hmm.. so that'd probably be the same problem with hooking a MT-32 up to a SCC-1?

Interesting that I'm just now reading about this "problem"

[BlueMax]

Been this way from the beginning.  The card sends MIDI data through both waveblaster header and joystick MIDI port identically - no way to change it - they're all hardwired that way.  An audio mixer is the only easy way to get around the mixing sounds you're hearing.

[Ari]

Hmm.. so that'd probably be the same problem with hooking a MT-32 up to a SCC-1?

Interesting that I'm just now reading about this "problem"

It's really not that bad. A simple audio switch is pretty cheap.

[Laust]

This type of setup (Y-splitters to "mix" audio) is harmful and should never be used. You risk damaging the outputs on the MT-32 and SCC-1 as they battle over which device gets to decide the signal voltage.

[Mike 01Hawk]

It's a MPU-401/AT btw, not a SCC-1

Wouldn't I be okay to just have a 'manual switch' ie... Mike 01Hawk plugging/unplugging the outputs depending on which module I wanna hear?

[BlueMax]

It's a MPU-401/AT btw, not a SCC-1

Wouldn't I be okay to just have a 'manual switch' ie... Mike 01Hawk plugging/unplugging the outputs depending on which module I wanna hear?

that'll work - it's just a pain in the rear.... and you could possibly wear out the connector jacks.

[Ari]

This type of setup (Y-splitters to "mix" audio) is harmful and should never be used. You risk damaging the outputs on the MT-32 and SCC-1 as they battle over which device gets to decide the signal voltage.

Heh, I remember you lecturing me about this a few years ago, when I had the same setup...  :wink:

[glendower]

This type of setup (Y-splitters to "mix" audio) is harmful and should never be used. You risk damaging the outputs on the MT-32 and SCC-1 as they battle over which device gets to decide the signal voltage.

Yeah, I was thinking about doing that, but then I thought--- wait, there will be two units putting voltage out without any protection to keep voltage from going IN to either unit... Hmmm... do I want to wreck my SW1000 and/or my MT-32? Gosh... replace a unit or two or get a mixer... HMMMMMMMMMM

I mean, at first it seemed like it would make sense and i was about to pull my splitters out of storage (I used them to split ONE input into TWO amps before... entirely different ).

[Galahad]

Hi Laust,

Would you mind elaborating more on what specfically is meant by using a "Y-splitter" setup, since I'm not familiar with the terminology?

Thanks!

galahad

This type of setup (Y-splitters to "mix" audio) is harmful and should never be used. You risk damaging the outputs on the MT-32 and SCC-1 as they battle over which device gets to decide the signal voltage.

[BlueMax]

There are some adapters out there that take one output (say an RCA out from your MT-32) and can split it into TWO outputs, so one could go to a sound card input, the other directly to an amplifier.  I used to use these to take two outputs from my amplifier and split+send the signals to FOUR speakers.  Nova9 sounded REALLY good with an MT-32 and four *gigantic* speakers with good bass capability!  Every tank shot would rumble the house!! 

These should never be used in the opposite direction to COMBINE two audio signals!  If you need to combine audio to hear two devices at once, use a mixer - nothing else!!

[Galahad]

Thanks for providing the helpful info BlueMax!  I don't think I am using this type of setup, would you mind if I ran by you what I'm currently using in case I need to change anything?

At present, I have the following configuration:

I have 2 audio input jacks on the back of my speakers. 
One of these 2 jacks is connected to my sound card. 
The other audio input jack is connected to my internal LAPC-I card (which serves as the MPU-401 to my CM-500). 
The LAPC-I is connected to an MCB-1, whiech is in turn connected to my CM-500 (the LAPC-I is only used as an MPU-401 interface though).

** However, since the speaker audio input jack that ultimately goes to my CM-500 does not allow for plugging in the 2 separate left-right audio connectors from the CM-500, I have a stereo adapter part that combines the left-right connectors into a single connector so that it can be hooked into my speaker.

Is this OK, or is this a Y-splitter configuration?

Thanks!

galahad

There are some adapters out there that take one output (say an RCA out from your MT-32) and can split it into TWO outputs, so one could go to a sound card input, the other directly to an amplifier.  I used to use these to take two outputs from my amplifier and split+send the signals to FOUR speakers.  Nova9 sounded REALLY good with an MT-32 and four *gigantic* speakers with good bass capability!  Every tank shot would rumble the house!! 

These should never be used in the opposite direction to COMBINE two audio signals!  If you need to combine audio to hear two devices at once, use a mixer - nothing else!!

[BlueMax]

From what I gather, yes - it does sound like you're combinging two audio sources using a splitter cable in reverse (as a "combiner" if there was such a thing.)

It would be far better to take the LAPC-1's audio (or the CM-500) and using an adapter (L & R RCA jacks -to- 1/8" stereo plug) plug it into the line-input of your soundcard.  That's plug #1 in your speakers.  The other MIDI device (CM-500 or LAPC-1) would be on its own for speaker input #2.  (those are nice speakers!  I've rarely seen speakers with more than 1 input!)

I would do the CM-500 with your audio card since you'll likely be using it more (playing MIDI files in Windows, etc), and can easily control the volume level with the knob on the unit.  The LAPC-1's volume is harder to control since there's no physical knobs, so you'll want the option of changing the volume via speaker knobs.  Do your speakers make you CHOOSE whether you hear #1 or #2?  Or do you hear both at once? 

You know.... a cheap, $30 mixer is still sounding like a good option here.

[Galahad]

Thanks again for the feedback BlueMax -- hope you don't mind, but if you could please clarify a few quick additional questions on this (please see below original comments), since I have no experience with using mixers or how they work.

It would be far better to take the LAPC-1's audio (or the CM-500) and using an adapter (L & R RCA jacks -to- 1/8" stereo plug) plug it into the line-input of your soundcard.  That's plug #1 in your speakers.  The other MIDI device (CM-500 or LAPC-1) would be on its own for speaker input #2.  (those are nice speakers!  I've rarely seen speakers with more than 1 input!)

I think this is actually almost the same setup I have I have now -- except the CM-500 is plugged directly into speaker input #1 (with L&R RCA jacks connected though 1/8" stereo plug plug/combiner), instead of to my sound card as suggested.  Speaker input #2 is connected as mentioned previously to my sound card.  But even using the recommended method of connecting to the sound card's line input, I would still need to combine the L&R RCA jacks from the CM-500 into a single stereo plug.  Would this approach be safer for the equipment though than my current technique ?

I would do the CM-500 with your audio card since you'll likely be using it more (playing MIDI files in Windows, etc), and can easily control the volume level with the knob on the unit.  The LAPC-1's volume is harder to control since there's no physical knobs, so you'll want the option of changing the volume via speaker knobs.  Do your speakers make you CHOOSE whether you hear #1 or #2?  Or do you hear both at once? 

Speaker inputs #1 and #2 play together simultaneously, if one is hooked up to CM-500 and the other to my Sound Blaster.  Not sure if this is a bad thing?  The reason I didn't connect my CM-500 to the sound card was because I was afraid this approach would be potentioally harmful as well, since wouldn't it be combining the CM-500 and Sound Blaster inputs into one single signal sent that is sent to the speakers?  (Thought that my current approach was safer, since the CM-500 and SB each connect to 2 different audio input jacks -- i.e., as two separate signals -- on the back of my speakers?)

You know.... a cheap, $30 mixer is still sounding like a good option here.

Sorry, don't mean to sound dumb or anything, but how would a mixer configuration be different than the way it's set up now?  (I have no current experience with using mixers.)