How far will a midi msg travel without a midi line driver in line?

Im doing a show at the moment and there is a midi keyboard substage in a bandbox and which is played. The keyboard is connected to a Harmoniser which is located in the operating position in the dress circle about 80-100 meters away.

The problem is that sometimes notes get locked on and they wont release on the harmoniser, the only way to clear them is to recall that programme again.

The harmoniser can not be moved either due to its only on spdif which wont travel that far and the rest of the outboard kit is using the spdif to AES convertor so I would have to move everything which is not good.

Any help would be great!!!!

15m.

More info on our web site at http://www.stagetec.co.uk/php/index.php?se...&contentid=1202

15m if its decent cable, some of the stuff I have bought before is only good for 6m before data corruption.

Try putting an active thru box somewhere in the data line.

MIDI can normally be transmitted quite a long way. This problem sounds more like a software bug than a MIDI transmission difficulty. You might like to read more on what we have discovered about sending MIDI long distances in many large installations here:

http://www.richmondsounddesign.com/faq.html#midilen

The bottom line is that MIDI 'line drivers' often are worse than raw MIDI itself, which is a current loop design and ideally suited to traveling long distances. Good luck!

Charlie

Nice to hear from Charlie again.

I have to say I agree with his comments here - I've quite often used midi running down a pair in the normal audio snake, with no problems, equally, in my studio I regularly get hung up notes with one device that just seems 'flaky' A whiff of a continuous controller and it falls over. It's a roland, if anyone is interested. I worked out long ago, that it was the synth, not the distribution system - I run a midiman 8 x 8 and by swapping devices, worked out by a process of elimination what the problem was.

Before you start messing with the cabling too much - try another MIDI device and see if that too has problems.

MIDI is very similar to 20ma current loop technoloy used in factory automation, which is a robust system that travels well, but only on twisted pair cable. The OP didnt mention what sort of cable that he used, but it its a pair from the audio snake it should be fine, "proper" DMX512 cable or Cat5 even better.

Doesnt sound at all like data corruption, as there is no complaints about notes being missed or wrong notes played, so that leaves the boxes at each end...

What I'd do is put a sound module in-line before the harmonizer, feeding the Harmonizer off the module's MIDI Thru, and see if the module output displays the same symptoms. And if it does try the module on a short lead to the keyboard. Bit of logical deduction to find the culprit!

As mentioned in our FAQ page (above) it's also very similar to POT (plain old telephone) technology which supports DSL technology at far higher speeds without requiring twisted pair cable. It does help but it's not required One major difference is that DSL incorporates error checking and correction and MIDI does not but at the same time DSL can transmit at megabits/s over a mile or more using just about any crap telephone cable found in the system.

Charlie

I run a Yami CS2X synth as a controller only into a triton rack. I use a decent midi cable of about 6m and I do get problems on the odd occasion. I have however known people use cabling much longer and not have a bit of trouble.
(hung notes etc etc) I believe it is the synth. (never liked it but still, I only use it as a controller now).
Going slightly OT. anyone know where I can get a controller (only needs to be quite simple as far as features go, patch up down, pitch bend and at elast one variable controller such as a mod wheel etc) with 88 notes that are UNWEIGHTED.
I have a stage piano (88 weighted) but I could do with something as a synth controller with 88 unweighted (that way I can have 4 or 5 splits per patch for effects and things) Sorry for going OT but it is on the subject of MIDI.

During the show I have just been touring with we were triggering midi down an 80m audio multicore with no problems and no line drivers. As was said before we tried one and it caused more problems than it solved....

Poppadom

I've got one of these surplus to requirement. It works absolutely fine. I'm moving my lighting over to wireless MIDI.

Feel free to PM me if interested.

http://www.philrees.co.uk/products/linedriv.htm

I think this is the correct term for what I need. We need to run a couple of MIDI cables over a distance of 30 metres or so and are no doubt going to run into delay problems at this length. Anyone have any recommendations for the different types of units that might help us with this? it will probably only be a maximum 2 cables which will be running to samplers offstage.

regards,
james

Moderation: Two similar threads merged. Most of the info you need is above.

The midi spec states a max cable length of 15m. My understanding is that this is a conservative spec, and many pieces of equipment will happily drive longer cables. Get some decent quality cable, and try it and see.

I just had a search for the philip rees line drivers, which will drive up to 1km - but their website says that production ceased a couple of years ago. You may still be able to find some dusty stock on a shelf somewhere, or check Ebay. No doubt there are similar products from other supliers.

Yep...data will get corrupt travelling that far, and unfortunately randomly.

Simplest solution is to include a MIDI Solutions Power Adaptor. They work well as a line driver and we're using them all over the place in the West End and touring shows without any problems - and you only need one at the keyboard end and nothing at the other end.

http://www.midisolutions.com/prodpwr.htm