Part of the lure of electronic music is the ability for one musician to perform highly complex compositions, or for the composer to hear his music without the need for performers at all. Splicing and digital editing allows this of course, but it is very tedious. As soon as analog synthesis became affordable, music engineers began looking for methods of automatic control for the systems.

Computer control was too expensive to contemplate in the early days (computer rental was over a million dollars), so a variety of techniques were tried: punched paper tape (Babbit’s work on the RCA machine), recorded control signals (Subotnik’s Butterflies) and elaborate digital sequencers (early Tangerine Dream). Some decent music was produced this way, but it was still hard work and the results were not really that complex. Electronic music that approaches orchestral music in scope had to wait for the appearance of cheap personal computers.

The first schemes (1974-84) for connecting synthesizers to computers were homemade or sold in small quantities by tiny companies. This led to a variety of systems that were mutually incompatible and so idiosyncratic that only their inventors could write software for them. The usual approach was to connect extra circuitry to the computer that either generated sounds directly or provided several channels of voltage control for modular synthesizers.

In 1983, several synthesizer manufacturers agreed on a communications protocol that would allow keyboard synthesizers to control each other (MIDI). This was very quickly picked up for computer applications, and today we have a mix and match situation, where any of several computers can be connected to one or more synthesizers, provided you have the proper software. MIDI is not perfect (the keyboard orientation and the rather slow data rate cause hassles), but it has provided an impetus for the development of software, has lowered the costs of computer assisted music, and has attracted many new musicians into the field.

The Musical Instrument Data Interface specification defines both the organization of the information transmitted and the circuitry used to connect systems together. The wiring is similar to that used for microphone cables, two wires within a shield. (The MIDI connector has five pins on it, but two of those are not connected. This is done for economy: five pin DIN plugs, widely used overseas for stereo gear, cost less than the three pin model.) Exactly one input may be attached to each output. Multiples are not allowed, but most devices have a “MIDI-THRU” output that simply passes data to the next device down the line. The basic configuration of equipment is a daisy-chain, with one master device controlling a series of slave synthesizers. An alternative arrangement is sometimes used where the data from the controller goes to a splitter box that feeds the data to several outputs, each connected to one synthesizer.

MIDI is a serial system. That means data is fed down a single wire one bit at a time. The bits are generated at the rate of 31,250 per second, but it takes ten bits to make a character and up to three characters to make a message, so it takes most of a millisecond to get anything said. As a rule, each action taken on the keyboard (such as releasing a key) generates a message. The typical message contains a channel number, a code for the key or other control affected, and descriptive data, such as key velocity. The channel number indicates which instruments are to respond to the data. There are sixteen channel numbers.

It is surprisingly easy to generate a lot of MIDI data. For instance, many keyboards have aftertouch; a feature that measures how hard you press on a key as you hold it down and feeds that information into the data stream. If you hit a chord and wiggle your wrists, you might generate several thousand bytes of data. This data may be vital, or it may be useless, depending on exactly how other instruments in the MIDI chain are voiced. When the data stream gets too full, bizarre things begin to happen. Instruments slow down, or messages can get lost. For this reason, many instruments and programs have a filter feature which removes selected types of data. You can even buy a special purpose box to do this.

Two streams of MIDI data cannot be mixed together in the simple manner two analog signals can. The group of bits that makes up a message must be kept intact or the meaning will be garbled. A device that combines MIDI signals, called a Merger, has a microprocessor in it that can recognize messages, assess a priority to them, knows how long the message should be, and prevents potential collisions by storing low priority messages until the output line is available. (This process is like switching freight trains onto a common track with out getting the cars mixed up.)

There are some other special tricks available in boxes. For instance there is a MIDI Delay which simply stores data a while before sending it along. If you connect an instrument’s MIDI out to its own MIDI in through one of these, you get some complex echo effects. Another type of box is a Mapper which can change data to compensate for differences in synthesizers. For instance, instruments often vary in the number of presets the can store. If you are using a fancy machine to control several simple ones, the fancy machine may implement all 128 preset locations, and the cheapies may only have 32. When you select preset 33 on the main synthesizer, it will send program change 33, which may have a unpredictable result on the slave. The mapper can be set to change that program 33 to anything you desire. [These features are also available as a part of better computer programs. Any synthesizer with more than 128 presets must have some sort of mapping feature.]

A type of box that is very popular is the MIDI patcher. This device has a lot of inputs and outputs, say eight of each. Controls on the box electrically switch inputs to various outputs, so you don’t have to fish around for the MIDI cables to change your system configuration. A particularly intriguing feature is that a configuration can be assigned a program number, so that the patch can be controlled over the MIDI line.

Problems

The MIDI protocol is often badmouthed because the original intentions of the designers are misunderstood. The system was created to allow a simple, cheap, and universal interconnection scheme for instrument controllers and synthesizers. The specification was developed by a committee made up of representatives from several companies, and contains many compromises between various needs and opinions. The specification was inadvertently modified in translation to Japanese, but since the company that made the mistake sells more synthesizers than all other companies combined, their implementation became the standard. The MIDI committee is still active, and adds features to the specification from time to time.

Speed

The complaint heard most often about MIDI is that it is too slow. It takes one millisecond (1/1000 sec) to send the command that starts a note. This is musically imperceptible ( in normal notation, MM=60,000) in simple pieces, but the delay across a twenty note chord can be noticed by a keen ear. The actual effect of this problem on the music is arguable (very few bands are together within twenty milliseconds). Probably the worst case for a performer is when the delay is unpredictably varied. The activities that generate the most frustration are elaborate computer controlled performances. The series connection MIDI system can clog up quickly when detailed control of a lot of instruments is attempted. The cure for this is to use a parallel connection scheme where the computer itself has several MIDI outputs.

Keyboardism

Another complaint is that MIDI sends the wrong information. It is clear that the standard was written with keyboard controllers in mind, and that is sensible, since the organ type keyboard is the most common controller for polyphonic single performer instruments. It is quite difficult but not impossible to design controllers with a continuous effect, such as a wind or bowed string instrument has, but the speed problem becomes extreme in such cases.

There is a proposal for a new standard, called “ZIPI” that addresses these two problems.

Stuck Notes

A perplexingly common occurrence is the stuck note. This happens because each note needs a separate message for note on and note off. If the note on is received, but the note off gets lost because of a loose cable, the note will sound forever. With many synthesizers the only way to get the note to shut up is to press many keys or turn the power off. (Most will quit if you change presets.)

Channels

The channelization scheme chosen causes a lot of confusion, but is not a problem. The channel numbers are really a tag on each command, and instruments have the option of ignoring commands that are not tagged a certain way. Difficulties arise when sending devices and receiving devices are not set to the same channel. The newer instruments can be set up to follow different channels with different voices, and this operation is often not clearly explained. The worst problem is that channel setting is usually hidden deep within an instrument’s menus rather than on the front panel where it belongs.

Program Numbers

There is also some confusion about program numbers. The MIDI spec allows for 128 programs, numbered 0-127. Many manufacturers seem to feel that musicians are not ready to accept the concept of program zero, and number their buttons 1-128. Even worse are the systems that use funny numbering schemes, such as 88 meaning program 8 of bank 8.

The problems arise when one encounters a maverick corporation such as E-mu or Oberheim that calls a zero a zero; and when you need to enter program changes directly into a computer program. Of course the widespread belief that 128 programs are not enough has thrown another monkey wrench into the works as each company develops its own scheme for calling up to 1000 presets.

Modes

One of the most troublesome features is omni mode. A synthesizer set to omni will respond to any MIDI message, regardless of channel assignments. A typical problem this can cause is found when using Concertware: the player sends initial program changes for all eight voices at the beginning of a selection, even if there is nothing in some of the voices. A synthesizer in omni mode will respond to all of the program changes and wind up with the program number requested by voice eight. It is a good idea to check the mode of the synthesizer first off, since you don’t know what the previous student was doing.(The only point to omni mode is to make synthesizers easy to demonstrate. I think it ought to be called “Salesman Mode”.)

Overcoming these problems is a challenge, but is similar to challenges musicians are already familiar with. Here are a few guidelines to maintain sanity.

Use a simple configuration, and stay with it. The MIDI system is designed to have one master controller running a bunch of slaves. Mergers allow the use of two or more controllers, and switchers allow quick reconfiguration of the system, but there is usually little to be gained. The people who repatch the MIDI lines a lot are usually trying to use a black box sequencer and a keyboard as controllers at the same time.

Don’t overload the system. Always filter out unnecessary information. Aftertouch, for instance should never be sent unless some device is responding to it. If you are playing with a sequenced track, the pedals are probably of interest only to the synthesizer you are playing.

Know the difference between OUT and THRU. OUT is information generated by the instrument. THRU is a copy of the input data. A few devices such as the Fadermaster provide a mix of the input and its own data at the OUT jack.

Take care of your cables. The MIDI connector is not noted for ruggedness and reliability. It is possible for a plug to look like it is in, but be loose enough to stop the data.

Read the manual. Read the Manual. READ THE MANUAL. Especially the part in the back that shows which MIDI features actually work. Pay particular attention to how to set the channel number and how to turn OMNI mode off.

Nuts And Bolts Of Midi

A MIDI message can consist of from one to several thousand bytes of data. The receiving instrument knows how many bytes to expect from the value of the first byte of the message. This byte is known as the status byte, the others are data bytes. Status bytes always have the most significant bit (msb) equal to one and data bytes have an msb of zero.[1] Because the msb of data bytes is always zero, actual values are limited to numbers less than 128. This restricts many things in the MIDI universe, such as the number of presets available.

Status bytes inform the receiver as to what to do with incoming data. Many of the commands include the channel number (0-15) as the four least significant bits of the status byte.

Commands are defined for about everything you would expect a synthesizer to do, to wit:

Note On
Note Off
Control Change
Program Change
Aftertouch (for the entire keyboard, set by the heaviest push)
Polyphonic aftertouch (values for each key down)
Pitch bend Note Messages
Note On and Note Off
The most common status is note on. [The actual bit values are: 1001nnnn, where nnnn gives the channel number.] Note on is followed by two data bytes, the first is the note number, the second is key velocity. If a keyboard is not equipped to sense velocity, it is supposed to send the value 64. Not too surprisingly, there is a status called note off, with the same data format. Note off is actually not used very much. Instead, MIDI allows for a shorthand, known as running status. Once a note on[2] is received, an instrument interprets each pair of data bytes as instructions about a new note. If the velocity data is zero, the instrument performs a note off with velocity of 64.

This manner of thinking, requiring separate actions to start and stop a note, greatly simplifies the design of receiving instruments (the synthesizer does not have to keep time), but creates the potential for hung notes when a note off gets lost. The MIDI designers provided some features to compensate for this problem. There is a panic command, all notes off, which is generated by some keyboards and even some special effects boxes.

The note numbers start with 0 representing the lowest C. “Middle C” is supposed to be note 60. Middle C is usually known as “C4″, but for some reason most manufactures call it C3.

Control Change

There is a group of commands called control changes, that relate to actions of things like foot pedals, modulation wheels, and sliders. Each command has two parts, defining which control to change and what to change it to. These are not very rigidly defined, so many systems allow assignment of controllers as part of preset definition. These are some of the official definitions: (numbers are actual data numbers)

1 Mod wheel
2 Breath controller
4 Foot controller
5 Portamento time
6 Data entry knob
7 Main Volume
8 Balance
10 Pan
11 Expression
A controller usually has a single data byte, giving a range of 0-127 as the value. This is rather coarse , so the controllers from 32 to 63 are reserved to give extra precision to those assigned from 0 to 31.

The numbers from 64 to 69 are switches or pedals:

64 Sustain 65
Portamento
66 Sostenuto
67 Soft
The numbers from 98 to 101 allow extened control changes called NRPNs and RPNs.

There are some specialized control messages:

121 Reset all controllers
122 Local Control
123 All Notes Off
124 Omni Mode Off
125 Omni Mode On
126 Mono Mode On
127 Poly Mode On
Reset Controllers and All Notes Off have the obvious effects. What is not so obvious is that neither will work on a synthesizer set to Omni mode.

Local Control allows you to disconnect a keyboard from the synthesizer it is built into. The Keyboard still sends MIDI Data, and the synthesizer still responds to MIDI data, but pressing a key will not necessarily produce a sound. This is useful when you are using a computer based sequencer and want the computer to have total control of the sounds.

Controller 0 is the Bank change message. A bank change followed immediately by a program change should take you to a new sound on a different bank, but the actual use varies from instrument to instrument. details

Channel Modes

The modes take some explaining. When all this was set up, most synthesizer keyboards were monophonic, like the Moog. (Monophonic here means they would only play one note at a time.) A few instruments could play chords, these were Polyphonic. The original MIDI spec assumed you would use a MIDI channel to control each oscillator on an instrument or you would have instruments that would play chords from one channel. No one foresaw the current situation, where multitimbral synthesizers can play chords in response to several if not all of the MIDI channels.

There are four possible combinations of the mode messages:

Omni On, Poly On or Mode 1: The synthesizer plays everything it gets.
Omni On, Mono (Mode 2): The synthesizer plays only the most recent note.
Omni Off, Poly (Mode 3): The synthesizer plays chords on one channel.
Omni Off, Mono (Mode 4): The synthesizer plays the most recent note received on its base channel. It also plays the most recent note received on the next channel, and the one after that, until it’s out of oscillators.
There is no message for Multi mode, so it has to be chosen from the synthesizer panel.

Program Change

The sound of a synthesizer is determined by the connections between the modules and settings of the module controls. Very few current models allow repatching of the digital subroutines that substitute for modules, but they have hundreds of controls to set. The settings are just numbers, and are stored in computer type memory. In a computer, a particular group of settings would be called a file. In synthesizers, it’s a Patch, Preset, Voice, or Tone for different brands, but the official word is program. A MIDI message may call one of up to 128 of these by sending data of 0 to 127.

Most modern synthesizers have more than 128 presets. Different manufacturers and models implement a variety of ways to make these accessible by MIDI commands:

Maps On some instruments, 128 presets are called up by the Program Change commands, but you can choose ahead of time which presets are called by which command. You can assign preset 4 to Pgm Change 1, preset 205 to Pgm Change 2, and so forth. This kind of list is called a Map, and is occasionally used for other operations too.

Banks Many instruments organize the presets in groups of 64 or 128. Then you pick which group is in use at any time by pressing buttons on the instrument. At least one of the banks will be writeable, and you can copy presets into it if you want to combine some from different permanent banks[3]. Bank switching may be possible via MIDI, but the method for doing this is not standardized.

Performances Many instruments let you define a multi channel (or complex keyboard) setup that combines various presets. These Performance setups (also called Multis, or Mixes) are stored in a bank of their own. The Program Change command then picks among these. Performance setups can also have settings for processors, volume, pan, and so on.

(When an instrument is in multi channel performance mode, program changes may change the performance setup, or may change the program on a particular channel. This depends on a setting hidden somewhere in the MIDI setup of the instrument.)

Program changes have data values of 0 to 127, but are supposed to be called Programs 1-128. Many Synthesizer and Software companies do not[4], so you basically have to experiment to find out what will happen when a particular application sends a program change to a particular instrument.

Pitch Bend

Most of the wheels and knobs on a synthesizer generate control change messages, but one gets a status message of its own. This is the Pitch Bender. A dedicated message makes it possible to efficiently send a bend value of 14 bits. If you try to do pitch bend with only seven bits of precision, you either have to restrict the range or you get audible steps. Unfortunately, no manufacturer takes advantage of this.

Aftertouch

On many keyboards, if you lean into the key as you hold it down, you generate controller messages. This is a very expressive feature. On normal aftertouch (also known as Channel Pressure) the values sent correspond to the key with the most pressure.

Polyphonic Aftertouch

Polyphonic Aftertouch sends separate pressure information for each key. This is a tremendous amount of information, and only a couple of synthesizers respond to it.

System Messages

The preceding messages are Channel Voice Messages which apply only to instruments set to the specified channel. System Messages apply to all machines:

Song Pointer
Song Select
Start
Stop
Continue
Clock
Midi Time Code
Active Sensing
System reset
With the first of these commands, several sequencers or computers can be cued to a preset point in a composition and run together. The clock command is a single byte that is “broadcast” by a master sequencer at the rate of 24 per quarter note. Sequencers can follow this clock and stay in tempo. This clock can be recorded on tape and played back with a suitable adapter. If this recording happens to be on a multi-track tape deck, complex sequences can be built up using many passes with a single synthesizer.

Song Select and Song Pointer cue up sequencers and drum machines, and Start, Stop and Continue control their operation.

An even more sophisticated synchronization system called MIDI Time Code is now available. In this system, time markers are recorded continuously on the tape. When the tape is played, sequencers will be automatically cued to match the tape. (This is a version of SMPTE time code, which does the same thing for video and audio editors.) Moreover, sequencers can be set to start doing their thing at arbitrary points in the composition, allowing such techniques as “slipping tracks” and eliminating the tedious process of composing long sequences of rests.

Active sensing warns an instrument if there is a serious malfunction. Once the active sensing command has been received, the instrument expects something on the MIDI line at least every 300 milliseconds (If the controller has nothing to say, it sends more active sensing messages.). If nothing is received the instrument shuts all notes off.

System Reset is supposed to return synthesizers to their power Up state. Hardly any recognize this.

The final group of commands are the SYstem EXclusive commands. These are commands that the manufacturer may define as they like. (Each manufacturer is assigned an ID code to prevent confusion.) The data stream may be arbitrarily long, terminating with a command known as End of Exclusive (EOX.) These messages are used for passing preset information, sequences, and even sound samples from one machine to another, and provide the foundation for the editor/librarian computer programs. Messages are not limited to program data; on the Yamaha instruments, system exclusive commands can be used to control everything, including the power switch.

Extensions To Midi

The Midi Manufactures Association has not stopped their work. Since the initial definitions they have produced the following:

MIDI Time Code Described above, MTC made it possible to link MIDI systems to video and other time based operations.

Sample Dump Standard This allows samples to be transferred from one brand of sampler to another.

Standard MIDI File This one allows MIDI tracks recorded on one sequencer program to be used by another, even if it runs on a different kind of computer.

MIDI Show Control This defines ways to automate theatrical productions, synchronizing lighting effects, sound, and even fireworks.

MIDI Machine Control This allows remote control of audio and video recorders. With this and Time Code, you can run an entire studio from the computer.

And then there’s….

General MIDI

General MIDI is a response to a problem that arose with the popularity of the Standard MIDI file. As composers began exchanging compositions (and selling them) in SMF format, they discovered that pieces would change when played on different synthesizers. That’s because the MIDI program commands simply provide a number for a preset. What sound you get on preset four is anybody’s guess.

General MIDI defines a standard list of voices. (This list is a sort of snapshot of the synthesizers that were popular in 1991. The easiest way to get it is to buy a GM compliant synthesizer.) Not only the names are standardized– envelope times are defined so the right sort of textures are maintained. Standard MIDI also defines channel 10 as the percussion channel, and gives a map of the drum sound to associate with each note. A GM instrument may create these sounds in any manner, so there’s still a lot of variation, but you no longer get a tuba when you expect a bass drum.

Most synths that support General MIDI do so by providing a bank titled GM. This is mostly a rearrangement of sounds from other banks.

General MIDI is most important in the soundcards that plug into PCs. These allow game programmers to create MIDI based scores instead of including recorded sounds for the music cuts.

General MIDI is coming to Macintosh computers as part of the expanded QuickTime system. Midi scores will be playable with no synthesizers at all!

How microphones work

Microphones just convert a real sound wave into an electrical audio signal. In order to do so, they have a small, light material in them called the diaphragm. When the sound vibrations through the air reach the diaphragm, they cause the diaphragm to vibrate. This in turns will somehow cause an electrical current in the microphone to vary, whereupon it is sent out to a mixer, preamplifier or amplifier for use.
Microphones are typically classified according to how the diaphragms produce sound.

Dynamic Microphones

Dynamic microphones typically use moving-coil technology. This consists of a diaphragm of usually thin plastic being attached directly to a dense coil of wire. The coil has a magnet either surrounding it or at the centre. As the diaphragm vibrates, the coil vibrates, and its changing position relative to the magnet causes a varying current to flow through the coil. This current is your audio signal.

Dynamic microphones have hardy diaphragms, but are typically damaged when the suspension wires break, due to dropping or rough handling. These are the little things that hold the coil and diaphragm in a floating position relative to the magnets.

Dynamic microphones have to cause a whole coil of wires to move, a mountain when you’re talking about little movements of air. This makes them not as sensitive as higher-grade microphones, especially to very soft sounds or high-pitched sounds, such as sibilants in speech or harmonics in music. They have a reputation of being very hardy, and some higher grade dynamic microphones can give a very clean and sensitive sound. Dynamic microphones are also known to give a ‘fat’ sound, which is flattering to those frequencies that the human ear can hear. They are usually not expected to reproduce the sounds they pick up very faithfully.

Because of their hardiness, they are usually used in live performances, where mic droppages and rough handling are the norm. As such the dynamic sound has also been identified as a ‘live performance’ sound that sounds cruder and more powerful at the expense of pin-sharp clarity. Performers such as Bono from U2 favour simple dynamic microphones over the more standard studio condensers for precisely that reason.

Condenser Microphones

The technology for condenser microphones has improved greatly in recent years, bringing costs down, increasing its hardiness, and making them even better. In condenser microphones, a static charge is impressed on the diaphragm or on a back-plate to the diaphragm. As the diaphragm vibrates, the distance from the back-plate to the diaphragm vibrates, altering the capacitance of the diaphragm and the back-plate. This fluctuating capacitance results in a fluctuating electric current. Voila! You have an audio signal!

Instead of moving a whole coil of wires, condenser microphones only have a thin diaphragm and solid back-plate making up a capacitor. Condenser microphones are therefore sometimes known as capacitor microphones. The quality difference of impressing a charge on the back plate or on the diaphragm is debateable, it is accepted that the smaller and lighter the diaphragm, the more accurate and pin-sharp the sound will be.

The developments in the clarity of condenser microphones has be partially spurred by the development of digital recording. As standards for recording improved, the quality of recording microphones had to improve to keep pace. However, just as digital recording has its detractors, the anal-ness and transparency of condenser microphones are also not universally popular. Most damning is the fact that condenser microphones tends to record sound as it really is. This means that vocalists must be really good, as any imperfections stand out clear as day.

Large-Diaphragm Condenser Mics

This has lead to the creation of large-diaphragm condenser microphones, which use the same basic technology, but have special larger high-quality diaphragms to produce a more flattering sound. Studios usually have an array of expensive large-diaphragm condenser microphones, as each microphone would reproduce the sound in its own special way. When the correct microphone is chosen for a vocalist, the results can be extremely flattering, making the singer much better than he or she really is.
The cost of a large-diaphragm microphone is usually attributed to the R&D cost of creating a microphone that records sound the way you want it, instead of the way it really sounds. Large-diaphragm mics can also maintain most of the high-frequency sensitivity of regular condenser microphones, making them sharp enough for digital recording to do the sound justice.

Phantom Power

Condenser microphones need a source of power to impress the charge on the capacitor. One of three methods is used. Either a battery will be inserted inside the microphone, a permanent charge is retained on the diaphragm or backplate thanks to some clever material scientist, or phantom power is used.

Phantom power is the supply of power through the ground cable of an XLR cable. Ranging from 9 volts to 52 volts, typically 48 volts, this power can be put into the cable either from a mixer, a phantom power box or a battery pack. A mixer might have a button that allows phantom power through the ground cable. A phantom power box is like an intermediate component between a mixer and a mic. It is a box (duh) connected to the mains that essentially just puts a charge on the ground cable. A battery pack does exactly the same thing, but works only with batteries instead of mains power.

Electret Microphones

Note: information in this section might not be very accurate.

Electret microphones are a variant of condenser microphones that mostly utilise a permanently charged diaphragm over a conductive metal back-plate. They somehow tend to be small, even minuscule, cheap and light. They are especially responsive to the range of sounds from the lower mids to the highest frequencies, i.e. they aren’t very good for bass. Back-electret microphones use a charged back-plate instead of a charged diaphragm. These may or may not be phantom powered. Electret and back-electret microphones have special preference for voice communication, where clarity of speech is essential at the sacrifice of perfect sound reproduction.

Plaintalk Microphones
The microphones that are designed specially for use with Macintosh sound-in jacks are called Plaintalk Microphones. They have a special mini-phone jack that is slightly longer than the standard mini-phone jack, and has 4 contact points instead of 3. The last contact point at the tip is meant to carry phantom power up to the cable in order to power the back-electret microphone. The other three contact points are in the same arrangement and have the same purpose and standard stereo mini-phone jacks.
The phantom power provided by Macintoshes is only enough for the microphones that Apple provides or recommends, and is thus not as universal as true 48V phantom power. However, since standard mini phone jacks will not be long enough to reach the last contact point, they can be used with Macintosh sound-in jacks easily as long as they do not require phantom power.

Ribbon Microphones

Note: information in this section might not be very accurate.
These are very rare, and only used in the best recording studios. They are very sensitive to shock and large sound volumes, and tend to be damaged easily. They consist of a thin ribbon of a metallic foil suspended in front of a metal plate. Sound waves cause the foil to vibrate, causing fluctuations in the electrical current. Thus, an electrical audio signal is created.

Now that condenser microphones are sensitive enough for studio use, they have mostly replaced ribbon microphones as the mics of choice in professional situations. Ribbon microphones are still reserved for very specialised applications. Condenser microphones are also hardier than ribbon mics and cheaper to replace.

Carbon Granule Microphones

These are the microphones found in many older telephones. They consist of a heavy diaphragm placed within a ‘bath’ of minuscule carbon granules, sealed to prevent the granules from falling out. As with graphite cables, the carbon is there to conduct electricity. The vibration of the diaphragm alters the resistance of current passing through the microphone, creating an audio signal. Note that this type of microphone requires an electrical current to pass through its circuitry, while dynamic microphones create their own current. Condenser microphones sometimes have batteries within them, so they might be considered as being able to create their own current.

These microphones are more responsive to middle frequencies and do not reproduce sibilants clearly. However, telephone speakers in the handsets are usually equally dreadful, so there isn’t much point in having a super microphone. They are cheap, hardy and in common use.

Pickup Patterns

Microphones are made with certain applications in mind. For example, stage use, studio use or field recording use. Microphones are not always expected to pick up sound universally and from all directions. The way that a microphone picks up sound from various directions is known as its pickup pattern. There are a few standard pickup patterns: Omnidirectional, Unidirectional, Bidirectional and Cardioid. Pickup patterns are usually depicted as polar diagrams, a circular graph of sensitivity of a microphone from various directions

Omnidirectional

Literally, from all directions. Omnidirectional microphones pick up sound well from all directions, and are frequently used for recording ambient and background sound. Omnidirectional microphones are also used for vocals, because of their lack of proximity effect. They could be used for recording of a group of vocalists, although the preferred method would to split the group into individual singers and each one having their own microphone.

Unidirectional

Literally, from one direction. Although cardioid microphones could arguably be unidirectional, the term ‘unidirectional’ is now usually reserved for ‘gun’ microphones. These microphones are long and rod shaped. Grooves on the side of the microphone allow sound coming from the sides to either pass through without reaching the pickup or cancel each other out. As a result, only a thin, cone-shaped area in front of the microphone is picked up satisfactorily. Gun microphones are good for recording individual voices in noisy locations, such as interviews, as well as picking up sound from a long distance.

Bidirectional

Literally…well, guess what it means. Correct! It picks up sound from two opposite directions! Also known as the figure-8 pickup, as the pickup pattern resembles a figure-8 when viewed from above. It used to be popular in the old days when two people would stand around a microphone and sing a duet, but now it is usually preferred to mic each person up separately.

Cardioid

Cardioid microphones have a heart-shaped pickup pattern. Probably the most common microphones in use today, They reject sound coming from the back of a microphone and are progressively more sensitive to sounds as the direction approaches the front of the microphone. They are favoured for stage use as they do not pick up the sound from on stage speakers or monitors so readily, thus preventing feedback. There are versions of the Cardioid pattern called Supercardioid and Hypercardioid, which represent increasingly limited ranges of pickup. As the pattern narrows, feedback rejection improves even more, but due to limitations of construction, a narrowing of the pattern does add a little sensitivity directly behind the microphone. The narrowing does cause the sound recorded to be more pinched and less flattering, but in a stage situation with many speakers placed in unsuitable places, a hypercardioid microphone can be a highly effective feedback prevention measure.

Proximity Effect

Cardioid microphones have a funny phenomenon called the Proximity Effect. This describes the increase in bass as the microphone moves nearer the sound source. Similarly, the further a cardioid microphone is from a source of sound, the more pinched it will sound. Experienced vocalists and producers have used this phenomenon to great effect, especially in simulating a punchy, ‘live’ effect by almost eating the microphone while singing. The proximity effect can also cause problems, especially when dealing with inexperienced speakers, as the tonal qualities of his or her voice will change as he or she moves his head.

Speciality Mics

A number microphones are considered unique not because of the technology involved, but more importantly, they are designed for certain unique purposes. Even so, considerable success has been reported in utilising these mics in situations they were not designed for.

Wireless Mics

Very visible in Karaoke bars and stage performances, wireless mics can be both convenient (no cables) and a pain in the ass (batteries needed, interference from outside sources). These mics are essentially the same as ordinary microphones with a transmitter. The transmitter can be in the body of a handheld mic (which accounts for the larger size of a wireless) or in a separate belt-worn pack (for lavaliers and instrument pickups (popular for electric guitarists). Wireless microphones typically transmit on only one unique frequency per mic. A ‘true diversity’ wireless system will have two antennae on the receiver end (which, incidentally, usually puts out a line-level signal for the mixer instead of a mic signal). When the signal strength between the two antennae varies, the receiver will opt to receive the signal from the stronger antennae. This switching can be very rapid and is usually unnoticeable. True diversity wireless systems are usually far less sensitive to radio interference and blockage than single-antennae systems.

Lavalier Mics

The familiar ‘interviewer’s collar pin’, which consists of a small, usually electret microphone worn at the chest, clipped to clothing. This can either be corded or wireless, though the latter is usually preferred. The wireless version runs into a transmitter, usually worn on the belt. Lavalier mics can be powered by batteries or phantom power, depending on the make of the mic. They have also been good for miking up wind instruments, clipped to the edge of the ‘bell’.

Bass Mics

These are very large diaphragm, usually dynamic microphones. Since they are usually employed in situations that produce very loud sound pressure levels, they are very sturdy and have lousy high-frequency response. Typically found inside bass drums of drum sets at rock concerts.

Pressure Zone Microphones

A general purpose microphone for amplifying a large source of sound, like a choir or a stage performance. These typically use condensor pickups, mounted a few millimeters over a flat surface, usually a metal plate integrated into the microphone. The concept is the sound reaching the metal plate will bounce back into the pickup, adding to the sound directly going into the pickup. They are also known as Boundary Microphones or Phase-Coherent Cardioids . They have remarkably good pickup, and when placed properly, give very little feedback for sound reinforcement. They are not very discerning in what they pick up, so they aren’t that good for recording.

My earliest Internet music experiences were sharing lyrics on Usenet. Check out this now-embarrassing post from 1992 in rec.music.funky where I’m trying to decode the lyrics to “A Year And A Day” from Beastie Boys’ Paul’s Boutique. I can still remember sitting in my walk-in closet, typing on an amber-monitor 8088, transcribing the lyrics to Diamond Dogs and Young Americans only to send them to someone I didn’t know so he could edit and post on Usenet (where are you, man? I think I owe you a cassette of that bootleg with SRV).

Until today, lyrics to popular songs have not been available legally in any mass capacity. The highly fragmented music publishing industry (not record companies) owns the right to publish lyrics and has been very slow to pull together and bless a way of legally distributing them on the Internet. As a result, lyrics have been relegated to rogue sites riddled with popup ads, inconsistent formatting, and often incorrect transcriptions. Every year we at Yahoo! Music say, “This is the year we’re going to sit down with the publishers and figure out how to offer lyrics to our users!” Unfortunately it’s proven to be an incredibly daunting task and we haven’t been able to pull it off on our own.

Today, however, we’re proud to announce that Gracenote has pulled together a comprehensive, consistent, and legal lyrics repository which we have licensed and integrated into the Internet’s #1 music site, Music.Yahoo.com. Now lyrics take their rightful place next to artist bios, discographies, videos, and downloads. All free to you, dear music lover. So check out the lyrics to hits like I’m The One, Start!, Freewill, or even Michelle (that’s right, we have The Beatles).

Also be sure to check our fancy Lyric Search, where you can search for songs by lyric snippet. What was that song that went …? Yahoo! Music can tell you.

Finally, thinking about those early Usenet posts got me all nostalgic so I decided to call professional lyricist Mike D from Beastie Boys and talk about lyrics for a minute. Here’s a snippet of the conversation, where he chides me for not knowing the lyrics to Brass Monkey (when he didn’t know them either), explains how the need for lyrics was the start of Grand Royal Magazine, and tells us that the lyrics for their new record (which they just finished last week) were “effortless”:

Download here

When you think lyrics, think Yahoo! Music. Or Rakim. But mostly Yahoo! Music.

ian c rogers
Yahoo! Music

By now you’ve likely heard the news about the Copyright Board’s ruling regarding net radio. Simply put, it approximately triples the amount paid to record labels via SoundExchange for streaming Internet radio over the next three years, changes the way the payments are computed (from what is called an “Aggregate Tuning Hour” basis to a straight “per play”), adds a confusing and onerous “per station minimum” fee with no maximum, and extends the new rates back to the beginning of 2006. Many small Webcasters won’t be able to afford this, and you can bet large Webcasters like us are all taking a hard look at the Internet radio business and our products to decide if it’s really worth the cost. Big companies might have more money, but they can’t stay in businesses where they don’t make any profit, a pretty simple business fact.

Compare the implications of this decision to terrestrial radio which pays NOTHING to SoundExchange, or even satellite radio which pays only 3-7% of their revenue to SoundExchange, and it’s hard not to be left scratching your head. The irony of all this, of course, is that this ruling will keep LAUNCHcast, Pandora, and the like out of your living room and push you toward FM, where the labels are paid zero. This decision cuts off a genuine future revenue stream before it has had a chance to grow.

It’s not just the Webcasters that will suffer. Higher costs, fewer Internet broadcasters and stations means less diversity overall, and less opportunity for the unlimited spectrum of Internet radio to become a discovery tool for curious listeners and a launching platform for smaller artists. Internet radio features thousands of channels in the narrowest of genres as well as personalized services (LAUNCHcast) and recommendation systems (Pandora), while FM radio (where it still plays music) plays the same songs over and over and the total number of satellite channels is less than five hundred. I am a satellite radio subscriber and can honestly say it doesn’t even come close to representing the diversity I get from my personal LAUNCHcast station. Listeners and artists ultimately lose if this infinite spectrum of music choice evaporates or even shrinks to just a few players. The implications for innovation in the space are catastrophic.

Which is why we are asking you to take action RIGHT NOW. We are supporting DIMA (a trade organization representing Yahoo!, AOL, MTV, Pandora, Real, Live365, and many others) and the SAVE NET RADIO campaign on this issue. Please take five minutes right now to visit SaveNetRadio.org, let your representatives know how you feel about this issue, send this post and these links to a friend, and put a link to SaveNetRadio.org on your blog, MySpace page, or site. We are on a very tight timetable to get our voices heard in Washington and legislation introduced before May 15th when the first payment is due under this new ruling. We need your help in making sure Congress is paying attention to this issue.

Thanks for your understanding and support,
ian c rogers
Yahoo! Music

It’s with great pride I announce the release of the SanDisk Sansa Connect, the new Wifi-enabled portable MP3 player set to free you from the USB cable chaining you to your PC, allowing you to listen to personalized radio, download music, share music with friends over Yahoo! Messenger, and view photos from Flickr, all direct over any Wifi network. Here are a few of the features not shared by either iPod or Zune:

• Personalized streaming LAUNCHcast radio
• Unlimited music downloads for $12/month direct over Wifi from Yahoo! Music Unlimited
• Dynamically updated “mix lists”
• Share music recommendations with friends via Yahoo! Messenger (your friend doesn’t even need the Sansa Connect)
• Photos from Flickr

It’s pretty fresh if I do say so myself, but why trust me? Here’s what Engadget had to say after spending a day with the device:

The Connect is tied to Yahoo! Music Unlimited for its subscription download model and streaming radio, and we’ve gotta say, a WiFi DAP really brings the model into its own.

Hells yeah. But they aren’t the only ones. Gadgetaholic liked it, too:

Sandisk has another winner here; I have no doubt. I am thoroughly impressed with the features available on this little device. Once you hooked this player up to your wifi network, it is almost impossible to put it down. This is what the Zune should have been.

You said it, homey. I also wanted to give a special shout out to my man Chris Leckness from Mobility Site for his very informative (and complimentary) unboxing and initial walk-through videos. Thanks, yo.

For me personally, the SanDisk Connect has put me in a completely different mode of portable music listening and discovery. I didn’t even connect mine to a computer for a week. I fired it up, started listening to personalized LAUNCHcast, and as songs I loved would play I’d grab the whole album. Then it was time to leave the house so I walked out the door and into the car, connected it to the line-in, and backed out of the driveway. The device elegantly said, “um, lost the connection to Wifi, dude”, so I flipped over into “My Library” and hit “Shuffle All” to start listening to the many songs I’d downloaded. Then when I got home the device was smart enough to wake up, realize there was Wifi available again, and restart my downloads. Simple and genius management of limited connectivity.

But there’s so much more. The Sansa Connect really underscores Yahoo! Music’s strengths and future direction, showing that we’re not just a way to get your music, but a set of services you use to manage your music experience across multiple endpoints. When you add songs to your library on the Sansa Connect, you’re also adding to your library on our servers and in Yahoo! Music Jukebox. The playlists you create in Yahoo! Music Jukebox show up on the Sansa Connect. When you rate songs on the Sansa Connect, the ratings will impact your LAUNCHcast station when you’re listening in the Web. The Sansa Connect is not an island, it’s part of your holistic Yahoo! Music experience. Yahoo! Music knows your music preferences, and helps you take them anywhere. Invest now, much more to come.

And of course you get other great Yahoo! features such as music sharing via Messenger and photos via Flickr. Can Rhapsody or Napster give you that? Thought not. How about Zune or iPod? Neither can give you unlimited music for one low price and neither are connected to the Internet for music discovery, playlists, and library management. My sixteen year-old daughter has a Zune, goes to a high school with 3700 kids, and has never once encountered another person with a Zune, shared music, or even used the Wifi functionality on the device. Welcome to the social? It’s 2007. How about welcome to the Internet. Duh.

[unfortunately controversial paragraph removed, explanation here]

So what are you waiting for? Buy one (or more!) now from Circuit City and subscribe to Yahoo! Music Unlimited if you haven’t already.

Word up,
ian c rogers
Yahoo! Music

Hopefully you’ve seen our Get Your Freak On corner, in which you, dear music fan, submit video of yourself dancing, lip syncing, or just generally messing about to your favorite song and we edit it together into a hit video. We’ve done these videos with everyone from Shakira to Weird Al, and the results have been sometimes hilarious, sometimes disturbing, but always popular.

We were aware the industry had taken notice, but now the LA Times has taken notice of the industry’s notice! Check out this LA Times article about the “‘Hips Don’t Lie’ Effect” in which they say Get Your Freak On “sent shock waves through the industry.” Congrats to the team for shocking the industry. Thanks Shamal for sending the link.

Hurry, I think today is the last day to submit yourself for the J-Lo video. Check out all the submissions as well as the completed videos in the archive while you’re there.

GYFO,
ian c rogers
Yahoo! Music

Hi Everyone:

Yahoo! Music has released a new music video player and it’s hot like Spring Break Daytona 2007. With the new player we are giving you control of your video experience, plus higher quality videos across both Mac and Windows, Firefox included. Try out these new features:

• When you watch a video in the new player, you will see a list of videos directly to the right of the video screen. This is the lineup of videos that will play next. If you like the videos in your lineup just sit back and enjoy the show. If you don’t like some of the videos, just click the ‘X’ button next to the video you want to remove, and it will delete it from your lineup.
• Also, you can finally browse more videos to play without leaving the comfort of the video player. Directly below the video, you will see a list of channels such as “Recommended,” “New,” “Top 100” etc. If you see any videos that you like from these channels you can watch them right away by clicking the play button, or you can add them to play next by clicking on the + Lineup button.
• If you don’t see the video you are looking for within the channels, you can also use the search box at the bottom right of the player. Perfect for when you want to interrupt that J-Lo video and switch over to nice-yet-obscure joints from Abstract Rude or maybe Capleton.
• Finally, you’ll be pleased to know we’ve finally joined the 21st century and our video player serves OS X and Firefox. Not only that, but we’ve raised the quality to 700kbps for all users.

We are still working out a few of the kinks, but please feel free to send us any feedback.

Also, for more information you can check out our complete tutorial.

Remember to rate artists and videos so we can continue to improve your recommendations.

There is a lot more to come. Stay tuned.

Brian Marshall
Yahoo! Music

When I talk to Yahoo! Music Jukebox users, I eventually hear a certain 4-letter word that makes me cringe: S-L-O-W. And, as much as I like to defend my favorite music player, that’s one I’ve never really had a good answer for… until now. On Tuesday, we made YMJ version 2.1 live as the download from our Web site. As I’ve mentioned before, we’re not trying to pack more features in as much as we’re trying to keep improving quality and performance. I can talk about things like fewer crashes and improved performance, but this time I’ve got some hard numbers to share.

I sat down with a stopwatch and tried some common tasks on my machine, from playing an MP3 to streaming a song from Yahoo! Music Unlimited.

Certainly every system is different, and your mileage may vary. But, I’m extremely proud of what we’ve accomplished here, and I hope you feel it too.

Get Yahoo! Music Jukebox 2.1

As with every release, there are a ton of under-the-hood changes – too many to mention, but I went through the list and picked some other highlights you may be interested in.

• Burner settings now available in Preferences dialog.
• My Music: right click menu items better enabled
• Memory leak in user interface fixed
• Uninstall/Reinstall no longer uses up a machine activation
• Auto update causes no longer causes improper shutdown
• Uninstall of YMJ no longer uninstalls Messenger skin.
• Save playlists in “Playlists” folder by default for MTP devices. Allows playlists to work on more devices
• Improved relicensing of YMU tracks
• Mini Mode YMJ now retains window position
• Ripping a CD no longer crashes when playing LAUNCHcast
• My Music loading enhancements
• Playlist created using “Create similar playlist” works again
• Navigating to the CD plugin no longer causes the playlist page to be unclickable
• Additional checks for album art for transfer to portables.
• Fixed crash when downloading lots of tracks
• Fixed deadlock if you go to the Download manager too quickly

Whew. We think that makes this one of the more important updates we’ve done. Let us know what you think.

And, if you’re into more new stuff, and need something to test drive the new YMJ 2.1, try out my FreshnessCounts playlist of new alt & indie rock for 2007. Let me know what you think of the tunes and the Jukebox they’re playing on.

Get to rockin!

Mick Orlosky
Product Manager
Yahoo! Music Jukebox