Kurzweil K2500 - PERFORMANCE GUIDE REV F PART NUMBER 910251 CHAP 15 Sampling Manual page 4

Sampling and Sample Editing
Sampling Analog Signals
the upper limit of audibility for most humans. The lower rates may be adequate for most
sounds, since many sounds have little content above 15 KHz. Sounds with a great deal of high-
frequency content, such as cymbals, should probably be sampled at the higher rates. You can
save memory by using lower sample rates for sounds without much high-frequency content—
acoustic or electric bass, for example.
Another consideration in selecting sample rate is the K2500's transposition range during
sample playback. The K2500 transposes samples by changing the sample playback rate; the
higher the playback rate, the higher the pitch of the sample. The K2500 can achieve a maximum
sample playback rate of 96 KHz. A sample made at 48 KHz can be transposed up only one
octave, since the playback rate doubles for every octave of upward transposition. A sample
made at 29.4 KHz can be transposed up approximately 21 semitones (an octave and a sixth).
There is no limit on downward transposition, regardless of the sample rate.
Each portion of a sample (each individual sample element made by the K2500 during the
sampling process) takes up two bytes of sample memory. A one-second stereo sample at 48
KHz consists of 96,000 individual samples (48,000 x 2), taking up 192,000 bytes (about 188K) of
sample memory. The same sample taken at 32 KHz takes up about 125K. A one-second mono
sample taken at 32 KHz takes up about 63K.
If you plan to do a lot of sampling, you may want to consider adding sample memory to your
K2500. SIMMS (Single In-line Memory Modules) are available at your dealer, or at most
computer stores or mail-order houses. Be sure to read "Choosing SIMMs for Sample RAM" in
Chapter 8 of the K2500 Reference Guide before you go SIMM shopping, though.
At a sampling rate of 44.1 KHz, each megabyte you add increases your sample time by about 12
seconds. The chart below lists a few standard sample RAM configurations and their total
sample time capacity (in seconds) at various sample rates.
2 x 1M
2 x 4M
2 x 16M
Mode
Use the Mode parameter to select mono or stereo sampling. (Keep in mind that stereo samples
take up twice as much memory as mono samples.) Use a value of Mono(L) for a mono signal.
You can use either Mono(L) or Mono(R) to isolate either the left or right side of a stereo signal.
Audio Sampling Input doubles as a two channel "drum" trigger, allowing audio signals to
trigger samples. On the Sample page, set Mode to Trigger. Adjust Thresh to control triggering
sensitivity. This triggers the currently assigned click program. The left input will trigger click
15-4
29.4
Mono 35
Stereo 17
Mono 140
Stereo 70
Mono 560
Stereo 280
Sampling rate in KHz
32.0 44.1
32 23
16 11
128 92
64 46
512 368
256 184
48.0
21
10
84
42
336
168