**bitmask**: a set of bits which represent individual single-bit toggles or groups representing small numbers. these are explained fully in the [hexadecimal primer](hex.md).
**clipping**: when a sample or playback stream exceeds the maximum or minimum values. this can cause audible distortion.
- this often occurs when a sample is amplified too much.
- it can also occur during playback if too much sound is being added together at once. in some cases the mixer can be used to reduce the volume. if this doesn't work, the clipping is caused within the chip's own mixing, and the only solution is to reduce the volumes of the notes being played.
**clock rate**: the timing at which a chip operates, expressed as cycles per second (Hz).
- changing this may change aspects of how some chips work, most notably pitch.
- some chips cannot operate at anything other than their designed clock rate.
- _Furnace:_ .dmf files may be read, and compatibility flags will be set to make them play as accurately as possible, but there may still be glitches.
- _Furnace:_ .dmf files may be saved, but full compatibility isn't guaranteed and many features will be missing. this isn't recommended unless absolutely necessary.
**hard-pan**: sounds can only be panned to the center, 100% left, or 100% right. this often appears in the instrument editor's panning macro as on/off toggles for the left and right channels.
**Hz**: hertz. a unit representing divisions of one second. 1 Hz means once per second; 100 Hz means one hundred times per second. also, _kHz_ (kilohertz, one thousand per second) and _MHz_ (megahertz, one million per second).
**LFSR**: linear-feedback shift register. a method to generate pseudo-random noise that loops, also known as "periodic noise". within a sequence of on-off bits, it does math to combine the bits at specified locations called "taps", then shifts the whole sequence and adds the resulting bit on the end, guaranteeing a different state for the next pass. depending on the locations of the taps, different lengths of noise loops are generated; for short loops, this will affect their tone.
**PSG**: programmable sound generator. any sound chip is a PSG, though the term is often used to specifically refer to chips that produce only simple waveforms and noise.
**release**: the part of a note that plays after it's no longer held, or the part of a macro the plays after it stops looping. usually applies at key off.
**resample**: to convert a sample to a different playback rate.
- this is a "lossy" process; it usually loses some amount of audio quality. the results can't be converted back into the original rate without further loss of quality.
- resampling to a lower rate reduces the amount of memory required, but strips away higher frequencies in the sound.
- resampling to a higher rate cannot recover missing frequencies and may add unwanted harmonics along with greater memory requirements.
**raw**: a sample or wavetable file without a header. when loading such a file, the format must be set properly or it will be a mess.
**register**: a memory location within a sound chip. "register view" shows all the relevant memory of all chips in use.
- saving to a .vgm file may be compared to "converting text to outlines" or similar irreversible processes. the results cannot be loaded back into the tracker.
- different versions of the VGM format have different capabilities, with trade-offs. older versions may lack chips or features; newer versions may not be compatible with some software.
- samples are stored uncompressed. PCM streams (such as DualPCM) can quickly take up a huge amount of space.
