MKWaveTable Database

The Timbre Data Base is a set of spectra derived from recordings of musical instruments and voices in various ranges. The Data Base was created by Michael McNabb.

The MusicKit provides a library of MKWaveTable objects that can be accessed by the DB (“DB” stands for “Data Base”) family of MKSynthPatches: DBFm1vi, DBWave1v(i), and DBWave2vi. Note that the use of the Data Base is strictly optional in these instruments. For example, if the Data Base is not used, DBWave1vi acts just like Wave1vi. That is, the waveform parameter may be passed either an ordinary MKWaveTable (as in Wave1vi) or a timbre string (as defined below).

To use the Data Base, you specify a timbre as a string (such as “SA”, including the quotation marks) to the MKSynthPatch's waveform parameter. MKSynthPatches with multiple waveform parameters accept multiple timbre strings. Each timbre string represents a group of MKWaveTables, one for approximately every whole step in the normal range of the voice or instrument. The MKSynthPatch selects the MKWaveTable appropriate to the frequency.

The entries in the database are referred to by string names, both in an application and in a scorefile. The precise MKWaveTable that's used depends on the frequency of the MKNote that's being synthesized. By default, the value of freq (or its synonym freq1) is used to determine the MKNote's frequency; you can find an entry based on the value of freq0 by preceding the database string name with the character “0” (zero); for example, “0BA”, the timbre will be selected based on the freq0 parameter instead.

The various timbre groups have different numbers of MKWaveTables, as given in the chart below. Internally, the MKWaveTables for a particular timbre group are numbered sequentially, with 1 corresponding to the MKWaveTable for the bottom of the range of that timbre. Specific MKWaveTables in a timbre group can be requested by adding a numeric suffix. In this manner, the automatic selection based on frequency can be overridden. For example, the timbre group “BA” (bass voice singing “AH”) consists of 15 timbres. The timbre string “BA12” requests the 12th MKWaveTable, independent of the frequency.

Some of the timbres are actually recordings of the attack of an instrument. These are best used with the MKSynthPatch DBWave2vi, which can interpolate between timbres. Note also that for realism, appropriate envelopes, attack/decay values and vibrato must be used.

Here are the string keywords for the timbres currently in the timbre database. Note that case is significant. The number in the third column is the number of MKWaveTables for that timbre. The normal range of the timbre corresponds to that of the corresponding instrument. For example, “BA” is normally used from about c2 to about d4.