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MIDI FAQs

What is MIDI?	What does MIDI send, if it's not sound?	How Can I get my MIDI Songs onto an Audio CD?
How to hook up One MIDI port to 3 modules?	MIDI Guy's Glossary of Electronic Music Terms

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Q: What is MIDI?

 

A: MIDI stands for Musical Digital Interface. It is a protocal to sending and receiving data between MIDI devices like a computer and keyboard. It is not sound. MIDI doesn't make a device do any more than the manufacturer designed it to.

 

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Q: What does MIDI send, if it's not sound?

 

A: MIDI sends codes that describes what action took place. When you press a key on a MIDI keyboard, it sends the MIDI channel it is set to, the MIDI note number and how fast (attack velocity) the key was pressed. When you release a key it sends the same information except how fast the key was released (release velocity) There are a lot of MIDI codes that can be sent. Here's a list of the most common ones and what they do in plain English not their Hex Codes. For a more indepth study, check out the Hal Leonard, Music Sales or Katamar MIDI Books in our Catalog. The MIDI GUY likes the MIDI Companion from Hal Leonard (Good Introduction Book), MIDI for Professionals from Music Sales (More details for the pro) and How MIDI Works from Katamar (Lots of practical examples to help understand MIDI and example MIDI Setups). But they're many others to choose from.

 

MIDI Port---This is the hardware that MIDI uses. There are up to three types of ports. MIDI IN---MIDI information is recieved on this port from other MIDI devices. MIDI OUT--MIDI information is sent on this port to other MIDI devices. MIDI THRU--MIDI information is passed from the MIDI IN thru this port to other MIDI devices. This port is sometimes left off keyboards or is software emulated on the MIDI OUT (Then it is called a Soft MIDI THRU)

MIDI Channel--- There are 16 possible MIDI channels that can go down a MIDI cable. Each channel is unique from the other in what it is sending. Think of a channel as an instrument, MIDI can have 16 different instruments playing at once. Want more instruments? Add more MIDI ports, multiple MIDI ports can be a single device like an Opcode Studio 64 or several different single port interfaces like a Sound Blaster, Midiman Winman 1x1 and MidiQuest Note One Plus all working at once in a single computer.

MIDI NOTE ON---This turns on a note on the keyboard (though it could be anything like a switch to turn on a stage light at a concert--MIDI Lighting!). There are 128 notes possible covering a range larger than a piano. There is also attack velocity, how fast the key was played, that is transmitted. There are 128 possible values for velocity.

MIDI NOTE OFF---This turns off a note on the keyboard. There is also release velocity, how fast the key was released, that is transmitted. There are 128 possible values for velocity.

PATCH CHANGE---Also called program change. This is the location of where a sound is found on a keyboard. Actually it could be any data that the manufacturer wanted it to be like a scene (a setup of lights) for a lighting board that is MIDI controlled. You could think of it as a P O Box, the sound is currently using the P O Number but isn't the sound, ie #11 is where a piano could be found on one synth but #1 is where a piano is found on a different synth. This could be confusing so a few years ago manufacturer's adopted GENERAL MIDI. This standard established a set list of sounds and their patch numbers so every GENERAL MIDI compatible instrument would respond with the right sounds for the same patch number or right drum sound for same note number. General MIDI instruments all have a piano sound for patch number one, every sound in their proper place!

CONTINUOUS CONTROLLER---This is a wheel or pedal that sends a series of continous MIDI values to alter the sound of synthesizer while the sound is being held. There's a lot of these. Mod Wheels, Volume, Pan, Breath, Data value are a few of these type of controllers.

SWITCH CONTROLLER---This is a pedal or switch that sends a MIDI value to alter the sound of synthesizer while the sound is beening held. It has two values - on or off. A sustain pedal is the most widely used of this type.

PITCH WHEEL---This is the first continous controller MIDI defined. It's used to change the pitch of a sound as you play it.They felt it was so important they gave it it's only MIDI data type so it's not included with Continous Controllers even though it's function is as one.

AFTERTOUCH---It's also called Pressure. It's also a Continous Controller but it unique in that it is a senor under the keyboard that is activated by pressing down on the key once it has hit the bottom of its travel. There are two type of AFTERTOUCH: MONO or CHANNEL which acts just like the Mod Wheel effecting all the currently held notes with the same single value. The other POLY or KEY is able to effect each key separately while beening held down. It is the only controller that has this individual ability.

 

See MIDI Guy's Glossary of Electronic Music Terms for more Info!

 

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Q:I only have one midi port on my computer, there are 2 or 3 things that I want to control from my sequencer program, how can I do that?

 

A:You have three options:

1. By using only 16 MIDI channels on your one MIDI port, you can connect the modules by using the THRUs. You'd go out of the MIDI port into the first MIDI IN then from that THRU to the next IN and from that THRU to tne next IN and so forth. You have to set the modules to respond only to certain MIDI channels, ie module #1 to channels 1-4, module # 2 to 5-9, etc.

2. Buy a MIDI Thru Box such as MIDI Solutions (check our Online Shopping Cart for price, etc.). You would take the one MIDI Out, connect it to the MIDI IN on the MIDI Thru box, then connect the MIDI Outs of it to the MIDI INs on your modules. The same setup of MIDI channels applies as in option #1. The advantage of this is that you elimate any MIDI delays caused by using the MIDI Thrus of the modules.

However MIDI delays can still occur because of the serial nature of MIDI. It's most likey to happen when using more than 8 MIDI channels tho the number of notes on those channels will determine the amount of delay. For example eight notes on each of the 8 channels playing on the same beat will produce an undesireable delay. On the other hand one note on each of the 8 channels playing on the same beat won't produce any delay. It doesn't matter if your sending the notes to different modules or all to the same module if you using the same set of 16 MIDI channels.

3. Buy a MultiPort MIDI interface such as MIDIMAN MIDIsport 4x4 (check our Online Shopping Cart for other models,prices, etc.). It supports 4 MIDI INs and 4 MIDI Outs for a total MIDI usage of 64 MIDI channels. Each OUT is it's own 16 MIDI channels. You're not sharing MIDI bandwith like the above options. You use this new interace instead of your current MIDI interface. It uses USB to connect to the computer. You hook up the 4 modules to the MIDI Outs on the interface. The advantage of this is that you have 16 MIDI channels for each module and the best MIDI timing possible.

MIDI delays are still possible even with the MIDIsport but if you are using more modules, each of the modules can now play up to the 8 note/8 channel MIDI delay problem outlined above before you notice the delays. Since most users use only 4 MIDI channels per module when they have several modules, they don't have MIDI delay problems.

 

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Q: How Can I get my MIDI Songs onto an Audio CD?

 

A: Since MIDI isn't sound you have to record the audio outputs of the MIDI devices into your computer. While there are programs like CD Recorder from DART (Available in our catalog/Online Shopping Cart)) which include a GM software synth that will convert a MIDI file into a Wave File. (It also records Audio CDs, does noise reduction and more).The resulting Wave file will sound like their software synth not your sound card, keyboard or sound module. In order to get your keyboard in to the computer you need to do the following:

1. Have a MIDI/Audio program, ie Emagic MicroLogic, Cakewalk Home Studio, or other program that can record audio while playing a MIDI file.

2. Take the audio output from the keyboard and plug it into the audio in (line input) of your sound card. Make sure not to have software monitoring thru the card on. If on then you will get a feedback loop which sounds very bad!

3. Make sure the song sounds the way you what it to.

4. Set the software up to record a stereo interleave audio file (See you software owners manual for details on this.)

5. Record the song in to the computer.

6. If the audio file is a stereo interleave file at this point, then you can burn a CD of the file. If not you will need to make it into one.Also remember that most CD players can only play a single session CD so burn your CD once you have all the files ready to be burned. You can't "add" songs to an audio CD even tho your CD burning software might let you.

 

 

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Loop Questions

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Q:What's the deal with loop tempos?

 

A:The tempo accuracy depends on how the loop was made. If the drum loop was created with a drum machine or sampler and a sequencer, then the tempo associated with the loop should be very close. Why not exact? Isn't 116 BPM (Beats per Minute) the same on everything? It's true that all computer based devices run off a crystal controlled clock. That clock controlls the rate the computer executes its instuctions. Otherwise nothing would work at all. That crystal is used because it's very stable but that doesn't mean all crystals are exactly the same speed. Your 200Mhz computer is more accurately a 199.59Mhz,201.001Mhz or somewhere in that range.It won't vary much from it's speed as it runs unless something big happens like a component failure or electrical brownout. Add on top of that the OS and program  your using which use software timming loops which can be affected by running multiple programs, locking to MTC or SMPTE, "realtime processing" of MIDI or audio, etc. Then your tempos can be affected. (You might notice this as "the feel" of the music changes between internal sync and MTC lock or playing you files on different similar systems where it feels like the tempo is slow or fast but the sequencer says it's still the same tempo.) The end result is the stated tempo of 116 for the loop may actually need to be slightly faster or slower by .001BMP to 1BMP. It's trickier with live drum loops. Hopefully the loop has a tempo marking - if it doesn't- you're in for a tuff time. Even if the drummer is right on, playing to a click track, the kick or snare can be off the beat by a small fraction of a second,  though not on every beat but still resulting in a loop that over time may vary from the marked tempo.

 

Q:I've got some drum tracks that don't have a tempo marking but I want to make some loops-HELP!!!!

 

A: The good news is that with today's audio sequencers like Logic Audio, StudioVision, Cubase, etc, it's not to hard to figure out the tempo. They have included a way to do it. You have to figure what sounds like a measure or two, tell the program that the meter is whatever you know or think it is and it will tell you what it thinks the tempo is. This same feature is also found on most sample editing software so if you have a computer , it's no problem. If you don't then you've got a problem! If you have a metronome, you can set it to different tempos until you find one that works. Some even have a tap tempo feature that will speed up the process. This trial and error method is painful but it does work.

If you know the length of the loop in seconds, the number of beats in a measure then you can try a little math. You do this:

60 divided by Loop Length in Seconds = n

n x 8 or 6 (assuming 2 bars) = BPM

The 8 is for 2-4 beat measure, the 6 is for 2- 3 beat measures.

 

Finally you can have your sequencer play the loop at the desired tempo, retriggering every two bars or whatever the loop is set for. Then, in your sampler, tune the loop until it locks up. This will alter the pitch of the loop which could make it undesirable to use.

 

Q: Why doesn't the loop stay in sync with the sequencer? I've got a "perfect" loop when I play it on the sampler.

 

A: TURN OFF THE LOOP! All those little timing differences in the computer, sampler, software and the loop itself become very apparent if you try to use the looping feature in the sampler to do the loop. You always retrigger the loop every two to four bars with a new note on the down beat so that it stays in sync with your track.

 

Q: I really like the loop but the tempo is wrong. How to change it?

 

A:You can adjust the tempo using either one of two methods: time stretching or pitch shifting.Time stretching is more involved and requires DSP tools. Some samplers have an on board time stretching function to lengthen or shorten a loop to correspond with the desired tempo. You can use this formula to convert BPM to Loop Length in Seconds:

 

BPM divided by 8 (2 bars of 4/4 time) or 6 (2 bars of 3/4 time) = n

60 divided by n = Loop Length in Seconds

Use this formula to convert Loop Length in Seconds to BPM:

60 divided by Loop Length in Seconds = n

n x 8 or 6 (assuming 2 bars) = BPM

 

There are also software programs like ReCycle from Steinberg, Logic Audio by Emagic, Sound Forge and Bias which can change the tempo without changing the pitch unless you want to do that. You can change the pitch without chaning the tempo if you want as well. The MIDIGuy likes the way Logic Audio allows you to change the groove of the audio within the file without having to chop the file into little pieces to change the feel. Used to the extreme this Logic Audio groove feature makes some cool effects!

Pitch shifting the loop will also change the tempo.To change the tempo by one beat per minute, use your sampler's tuning function to tune the loop up or down approximately 22 cents. Or, have your sequencer play the loop at the desired tempo, retriggering every two bars ro whatever the loop is set for. Then, in your sampler, tune the loop until it locks up. This will alter the pitch of the loop which could make it undesirable to use.

 

Q: Got any tips to expand the possiblities of the loops I have without spending more money?

 

A: Try triggering your drum loops on "up" or "off" beats. If you layer different loops of the same tempo it can be very interesting. You can easily turn a straight "one-two" groove into a wild, jazzy shuffle by offsetting two loops by two triplet eighth notes. Make sure to use differnet MIDI channels for the loops as this makes it easy to slide the loops in time. Also chop up different loops into single drum notes, ie kick , snare, etc. and layer them on top of a loop's kick or snare to get that "huge" drum sound using different MIDI channels so you can mix them easily. If you have the time get a sample editor or experiment with the audio features you already in your programs. Do things like silence the loops kick or snar so you can use a different sound and place it where you want to put it. Just remember this: Try anything you can think of!

 

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Computer Questions

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Mac Questions      Windows Questions

 

FAQ General Questions

Q: What is the best computer for MIDI/Digital Audio?

 

A: The answer is there isn't a best computer. Rather it's finding the right software for the job. Software is a tool to do a job you need to have done. Computers are universal machines that only work as well as the software they use. The software and how well it works on the computer is what's important. The match of both defines the right computer. Never use the minimum computer requirements for software, while it will work to some degree, best performance is always obtained by using the best hardware for the job.

There are many elements that make up computers and software. Simply stated they are: Hardware components like motherboards, hard drives, etc; Basic operating systems like BIOS in PC; Main operationg Systems like Mac OS, Windows 95; Additions to the operatings systems for special hardware or software purposes such as Device Drivers or Extensions for video cards, modems, printers, etc and finally the software itself. You can see that with all the many parts that make up a computer and the software, it is amazing that we can get it to work at all! But then a bee according to physics can't fly!

 

The Mac System of hardware and operating system offers the user a simple to use and maintain system to operate the software that's right for the job the user has selected. Since the hardware and software comes from a single source (which includes the clone manufacturer UMAX, their designs are based on Macs and operate as 100% compatible to 6400 or 9500 series Macs), the user has no need to learn all the ins and outs of how to make the computer work. This explains why you don't see many Mac Consultants, THEY ARE NOT NEEDED. The computer either works or is broken which explains why there are service centers for repair. You do see Mac Tutors, a lot of people have either a hard time understanding their user manuals or don't want to spend the time finding how to do only the tasks they need to know, not everything the software can do (which is why there is a lot of training manuals and videos). In The MIDIGUY'S experience, the Mac OS is more problem free from setup and maintenance troubles. This is why more Audio and Music Professionals use the Mac OS than Windows. If you can't afford the expense of consultants and downtime then you should use the Mac OS if the Audio/MIDI software/hardware you want to use is available on both platforms.

 

 

The Windows Operating Systems (3.1, 95, NT,2000, ME and XP) offers the user a simple to use system to operate the software that's right for the job the user has selected. The variety of hardware options available for the user require expert advice to select the proper mix of hardware to work with the software. This is where all the PC consultants come in. Their job is to help select and maintain the hardware/software balance for the user. If the user doesn't use the services of a consultant then he/she has to become their own consultant. Bad advice is costly in both time and money. When choosing to use the Windows Operationg systems, The MIDIGUY recommends dedicating the computer to just MIDI/Digital Audio but include a modem sans fax options enabled for best performance. Also don't use "Preconfigured" systems that can be purchased at chain stores or by mail order. A BUILT FROM SCRATCH computer with the proper parts will ensure satisfaction. We build PC computers that are designed for MIDI/Digital Audio users and have lots of happy customers. We also have disappointed users who have bought "Preconfigured" computers or are trying to make the computer do everything which results in a Jack of all Trades but MASTER of NONE. We do the best we can for these users in helping them but sometimes you can't rework these computers into providing the performance they should be capable of due to design, multiple use or cost problems.

 

 

 

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