midi questions

[Marina]

I hate to let everybody know just how ignorant I am, and especially since I'm trying to be a part time pro-audio tech. Actually I do have a fairly decent electronics background, but huge gaps of understanding in the pro-audio field. Anyway, I'm not sure if this topic is within the scope of the forum either, or if I'm in the appropriate part of the forum.

But here goes. I was presented with a Roland FP-4 with a complaint that it would receive midi but only outputs 1 piano sound. I felt like there was not enough information in the complaint and told my boss I'd get back with him on it. I didn't want to embarrass myself or him calling up the customer to ask stupid questions.

What I understand of midi is limitted, and I don't know how much I'll have to learn to be functional in dealing with it. I know a board can be used as a controller & local control can be turned off to keep the controller from also playng it's sound as well as what's put out on the midi. They both have to be on the same channel. I'm familiar with a board being used to play through a sound module, where the patches are selected at the sound module, but I guess the controller can also be used to assign different sounds to other instruments.

Can anyone give me some insight on how I should be approaching this? Does anyone know of a good resource for learning about midi that's practical & concise? Your help is very much appreciated. TIA

[jrfrond]

There are a lot of techs who do not fully understand MIDI. In addition, MIDI implementation varies from mfr-to-mfr. MIDI implementation refers to what MIDI functions the unit can transmit and receive.

In order to troubleshoot a MIDI 'problem" (most are really user error), you need to know that MIDI implementation of both units in question here. You are definitely receiving MIDI "note on/off" information, but since only one patch is usable, you need to find out more about patch-change information, i.e how it is handled by the FP-4 and also by the controller in question. "Local Control ON/OFF" is like virtually (dis)connecting MIDI from the internal keyboard to the internal sound engine.

Usually, this info can be found in an Owners Manual.

[Enzo]

If it helps...

Think of MIDI signals as you might a paper roll from a player piano. There is no music contained in it, only instructions. SO the MIDI signal has no essence to it in terms of sounds. It sends note on and note off signals to some receiving device. It tells that device that it wants it to play note # 123 in whatever voice it might have on the particular channel selected. I can plug a MIDI signal into a piano sound module and it will play piano sounds. I can unplug the MIDI cord from that module and stick it in a drum sound modulpe and drum sounds will come out in the same pattern as the piano sounds did a moment ago.

SOmetimes MIDI drum tracks are amusing to listen to when played into some synth patch or even piano.

All the MIDI send knows is the channel it intends to control elsewhere and the notes it wants played and when. Yes, there is other stuff like aftertouch and velocity, but the idea is the same.

As the MIDI world evolved they made certain additional standards. General MIDI was an attempt to get everyone on the same page. Basic MIDI doesn;t specify any sound, but General MIDI groups things by instrument - or tries to anyway. I don;t recall the numbers, but they tried to make things a little more consistent so similar sounds would be under similar numbers. But still there is no piano-ness to the MIDI send.

MIDI can also send programming changes if the receiving device is able to accept them. You can remotely change patch numbers. But the receiving device must be prepared to heed them. There is usually a parameter to set.

If your sound module only makes one sound, it sounds to me also that it at least accepts the play signals, the program changes is another matter. You need to look in the owners manual to see what set up it needs.

I tell people I know how to fix them, but I don;t know how to operate them. There are plenty of MIDI devices out there that might be a lot easier to control if you had a "site map" for the thing. I often have no idea what page under what menu some function control lives. Receiving on what channel is adjusted, but receiving program changes is usually a separate function. So just because it receives on your channel doesn;t mean accepting program changes is turned on.

Perhaps you know a keyboard player who would be kind enough to show you some MIDI basics. PLug your controller into something else and verify you can send program changes to it. And can you try a different controller just in case?

I am not familiar with the FP4, but if it is programmable, then it has a memory. ANything with a memory can become corrupted. Those sorts of things have a re-initialization procedure. it is usually holding down two or three panel buttons while powering up. otherwise, somewhere in a menu is "restore factory settings" or some such.

I suspect less these days, but in older gear, some parameter might have a range of 1-10 and the number 22 is in its memory as a result of some glitch. 22 of course means nothing to the programming. I have also seen devices that had an extra digit, that would remain unseen on the display. By accident we discoverd that by holding the down button, it counted down enough to get into the real 1-10 range instead of 111-110.

SO perhaps your unit needs a re-init. Any time you reset something like that though, it will erase any customization the owner might have done.


And you know what? I often find customers are more likely to think I am honest if I answer some questions, "I don't know."

[Brad1]

Apparently, an FP4 is a piano with a keyboard. Does it play without a MIDI cable attached? Does it change sounds from the front panel? If so, it's probably OK, but the parameters aren't set correctly in either the controlling device, or the FP4, for program changes. I'm only assuming that there is another device that is supposed to be controlling it from the statement that "it would receive MIDI".

This could be a computer sequencer program, or another keyboard, possibly. All you can do is check that it changes patches from the front panel, and does other functions properly. You can download the manual from the Roland website.

If it seems to be working properly by itself, there is no way to tell if it is communicating properly with the proper parameters without having it attached to the other device.

If it's hooked to a computer sequencer program, and it simply isn't changing patches, the operator may need to learn how to insert Patch Change messages into the sequence. And, it's also a good idea to insert a GM and/or GS Reset System Exclusive message at the very beginning of a sequence...before ANY note or patch data. This will reset the module(s), and then tell it to change to the new patch.

They must have their channel matched, and the sequencing program should not have necessary messages "filtered" through any sort "MIDI Data Filter" within the program.

If it's another keyboard controlling it, both have to match channels and controller parameters for it to communicate properly. Without knowing what is on the other end...there is no way to even guess what might be wrong. You'll need the manuals of both devices.

See if it seems to work properly by itself. Then find out what's on the other end that may be messing it up.

Brad1

[Marina]

Thanks, and more questions

So, is it correct that the sounds are always only selected from what's available on the receive instrument? The actual sounds are not transmitted from the controller, right?

I downloaded the FP-4 owner's manual & can see information regarding transmitting Program Change, but nothing on receiving Program Change. Is this a problem?

I may get another chance to tackle this on Friday or Saturday.

So if the controlling program is basic MIDI vs GM, could it be deficient in ability to select a patch? GS is a Roland thing, with more specific bank/patch number selection?

Brad, thanks for what looks like a comprehensive approach to dealing with the issue. I'll try to follow your directions.

Merry Christmas, everybody!

[Brad1]

So, is it correct that the sounds are always only selected from what's available on the receive instrument? The actual sounds are not transmitted from the controller, right?

I downloaded the FP-4 owner's manual & can see information regarding transmitting Program Change, but nothing on receiving Program Change.

So if the controlling program is basic MIDI vs GM, could it be deficient in ability to select a patch? GS is a Roland thing, with more specific bank/patch number selection?

The transmitting device sends a message to the receiving device to change to a particular patch.

The FP4 receives MIDI Patch Change, according to the manual and MIDI Implementation Chart.

Doubtful that the program or other device is only "basic MIDI". It's probably at LEAST GM, if not also GM2, GS (Roland spec), and/or XG (Yamaha spec).

That keyboard may even need a Bank Select message to choose certain sounds....(Bank 1, Patch 3....Bank 2, Patch 7...etc.)

How that is chosen from the other device depends on what the other device is...and we don't know. You need to find out what it is connected to, if the problem EVEN IS that it isn't responding to another device. We don't know. For all we know, "responds to MIDI but won't change patches" could be someone's wrong way of saying "it makes sound, but won't change sounds by pressing buttons".

Do the buttons work? Can you change things? What is the person who owns it trying to say? You need to grill the customer to find out. You can't fix what you don't know is wrong. There may be nothing wrong, except Operator Error.

Good luck,

Brad1

[Marina]

Thanks Brad,

The unit is now accross town, and if I get another shot at it, I'll get the whole story from the customer first.