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Midi to XLR?

m_stobbs

I'm not sure where i should start my search, but I'm looking to get a converter that runs Midi to XLR and then to put an XLR to 1/4" so that i can use a bass or anything else that doesn't have a Midi port on it to control a synth. Any recomendations?
Thanks
Matt
September 5, 2006 @06:45am
TimOBrien

Learn what MIDI is.
MIDI is not sound, just 1's and 0's.
Here's a starter guide:
http://www.tweakheadz.com/how_to_get_started_with_midi.html
September 5, 2006 @01:55pm
tech1

I think we need to clear up some concepts first. MIDI and audio are completely different entities. MIDI is not sound. MIDI does not make sound. MIDI is simply control data. It tells a device what to do, when to do it, how strongly to do it, and for how long. The most common application of MIDI is to trigger synthesizers and samplers via note data. However, MIDI can also be used to control faders on a mixer, lighting on stage, robot movements, and a wide variety of other things.
Audio, on the other hand, is sound. Very briefly, it is stored digitally as a huge table of samples that play back at a pre-defined rate. In the analog world, audio is simply a wave (albeit a very complex wave). Digital audio is converted to an audible wave through an A/D converter. This is how we are able to hear digital audio.
The basic problem is that you can't take control data and "convert" it into audio. You need to use the control data to trigger audio events. A MIDI note, for example, will be sent to a synthesizer, which interprets the incoming signal and responds to it by trigger a totally separate event: the audio output. There is no direct "conversion" of one type of signal into another; MIDI notes tell devices what to do, and the devices respond by playing audio.
What further complicates your questions is that you want to go from audio to MIDI. A bass will only send audio out. Synths respond to MIDI coming in. The only way to do what you are proposing is to use a third program or device that is built to interpret incoming audio signals, and then use them to trigger MIDI events. I think your best bet is to purchase either a synth guitar ( http://www.sweetwater.com/store/category/c593 ) or guitar-to-MIDI converter ( http://www.sweetwater.com/store/category/c939 ). The program Max/MSP can also do this, but it is EXTREMELY difficult to set up, especially for someone new to the Max environment.
Hope that makes sense...
September 5, 2006 @02:12pm
m_stobbs

Thanks for the posts!
Though i have only been using MIDI for a little over a year now, I've read up on it a bit and in a book called "Midi Production" it explained how it was possible to make an adaptor cable that is "midi on one end and XLR on the other" since both only use 3 pins.
Putting an XLR to 1/4" inch on the end of this adaptor cable was my idea, which i just assumed would work because that's what adaptors do.
I'm also aware that it wouldn't be a very "solid" signal as a result of all the adaptors, I just wanted to see what would happen as a result of running this adaptor into my synth.
Thanks!
Matt
September 5, 2006 @05:14pm
tech1

That cable idea is actually incorrect. A MIDI cable uses 5 pins, and an XLR uses 3. It would definitely be an interesting experiment, but the analog signal from the guitar likely would not carry the proper type of signal for a MIDI device to intrerpret. Guitars output an analog signal, whereas a MIDI device will be looking for digital signals. In fact, ou may even risk damaged the MIDI port on your synth if the audio signal is too hot. I'm not sure what voltage difference there would be between a guitar signal and a MIDI signal, but I would have to advise you not to try this.
That said, it would be cool if it worked....
September 5, 2006 @06:10pm
DAS

A MIDI cable uses 5 pins, and an XLR uses 3.

A MIDI connector has five pins, but only three of them are required to satisfy what is needed for MIDI transmission. Many MIDI cables only have three wires...some have all five because there are some specialized applications that do call for the remaining two conductors to be used, but those are few and far between.
September 5, 2006 @06:34pm
MAT69

Ok guys.....
First, to respond, YES it is possible and some times needed to convert MIDI to XRL....
There was ONE unit doing it called "MIDI Boost", but their story is over now....
Yes, you can simply make a cable yourslef, by using a XLR cable and putting MIDI plugs at each end....
But yes, it is a risky business that on tje long XLR cable you loose some "0"s and "1"s, but it worth the try....................
Education for previous bad answers:
You may need to convert a MIDI to XLR when you need a MIDI cable longer than 50 or 75 feet..........
Like if you want to control the light board in the Front Of House during concerts.... Also, if you want to control sounds units of the FOH soundman, from a computer (sequencer) on the stage....
Usually, you would like to send your MIDI cable in the "snake/splitter" that goes from the stage to the FOH board..... And this is somewhere between a 100 and 300 feet of traveling in XLR format.......
If you want to make a cable (adaptor) MIDI to XLR, just use the 3 middle pins on the 5 pin MIDI plug, and link them to the XLR 3 pins wire..........
MIDI cables have 5 pins, but only 3 are in use...........
Good luck !
Peace to everybody
MAT ;-)
November 8, 2007 @08:30pm
DAS


Education for previous bad answers:

Well, it's not quite as cut and dried as you suggest above. First, it technically doesn't matter which type of connector is used. Obviously you need the MIDI DIN plug to match with MIDI gear, and equally as obvious you'd need an XLR if you wanted to use a snake. Both will carry the signal, as most MIDI devices only use the three pins, etc. (all this has already been covered above).
Where I have a problem with this latest bit of information is in the suggestion that merely making an adapter between the two is enough. It often is, and often does work just fine to do what MAT69 writes, but not always. MIDI is not a differentially balanced signal, which means you can't run it down extremely long lengths of wire and expect it to work properly. I've run MIDI down snake lengths between 50 to 150 feet before and had mostly good luck, but that signal is in many ways not as robust as a truly balanced audio signal that's hitting either a balanced transformer or (usually) a op amp at the receiving end designed for balanced signals.
Feel free to try it, and it may work, but you just can't ASSUME it always will work.
November 8, 2007 @08:55pm
reekster

Wow, things seem to go sideways fast.
- I still think the thread above sometimes suggest that just creating a Midi to XLR cable is going to allow M-Stobbs bass guitar to trigger a Midi equipped device. This of course will not work.
- While a Midi connector does indeed have 5 pins, and yes, someone did correctly point out that many Midi cables are only wired for 3 pins, you only need two of these pins for a Midi Signal.
- Also, certain types of cable will allow Midi to be ran 100's of feet. I have done a huge installation where we ran Midi, without any types of boosters, up to 300 feet successfully.
November 12, 2007 @04:34am
ltheonel

BASS GUITAR to MIDI INTERFACE!
A digital signal (1s and 0s) is really a square wave. The frequency of this signal, i.e. the maximum rate of 1s and 0s (bits) is defined in the midi protocol as 38400 baud; that is 38400 bits per second.
The equipment which receives and transmits this information; Keyboard, computer etc, differentiate between a 1 and 0 by levels of voltage on the cable. In a lossless world and for midi this would be 5v for a 1 and 0v for a 0.
Now midi is a protocol which expects certain sequences of 1s and 0s to communicate the commands. Which means a whole bunch of 1s and 0s need to be sent in a very particular order for a single command i.e. a trigger?
Ignoring all the electrical stuff for a moment, to create MIDI on a bass guitar, you would need to be able pluck a string exactly 38400 times a second with a perfect on off pattern to replicate the correct sequence of 1s and 0s required by the midi protocol for a simple trigger. And as for the electrical stuff... YOU CAN NOT DO THIS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
So: If you want to use your guitar to trigger MIDI events on a sequencer/keyboard/PC whatever then you need a MIDI Guitar. A regular Bass Guitar not matter how good a player you are cannot do this.
MIDI TO XLR CABLE = increased transmission distance. Erm NO well a little.
WHY?
By XLR cable you probably mean star quad or musi-flex cable or otherwise shielded twisted pair.
The shielding protects from radiated noise from mains cables, or lighting rigs for example. That is it protects a little from this noise. The fact that it's twisted means nothing with regard MIDI; it only becomes useful in a balanced system. The shielding is the mechanism which allows you to transmit MIDI further through an XLR cable: Standard midi cables are unshielded.
If you are serious about tx’ing MIDI over long cables you really want to balance the signal and make use of a line driver to supply the current required for the additional ‘drop’ voltage will experience over the distance.
OK WHAT IS THIS **** I HAVE JUST READ
The above are random thoughts not well explained or referenced to indicate two things to M_Stobbs:
  • Things are not simple!
  • You cannot trigger midi events from your standard bass guitar via an XLR to ¼ inch convertor without using a very clever box in between.
February 1, 2008 @08:22pm
pat23765

thank for this information. i am also tyring to do this thing with midi. it helps me
childrens book
September 3, 2008 @04:08pm