Specifying the Reverb Time & Start Point
16
SREV1 Sampling Guide
Specifying the Reverb Time & Start Point
Impulse-response data files (i.e., TM4 format files) do not specify a reverb time value,
so the SREV1 automatically calculates values for the reverb time parameter that is used
by the RC-SREV1. This is based on the length of the sampled data, not the length of the
file. You can, however, specify a reverb time (RT) by editing the file header information
with IREdit. The SREV1 will then base it calculations on the value you specify.
Say, for example, that you specify a reverb time of 2 seconds (e.g., RT=2.0) for a file that
the SREV1 would have automatically calculated a reverb time of 2.1 seconds. Based on
your value, the SREV1 recalculates the impulse-response data and passes on the results
to the convolution processors. Basically, the SREV1 calculations affect the way in which
the reverberation fades out.
You can also specify the point at which reverberation fade-out processing begins. This
is called the reverb start (RS) point. Technically speaking, this is point at which the
SREV1 begins exponentially attenuating the reverb data.
Essentially, reverberation consists of two components: the early reflections and the
main reverb which follows. Early reflections define the character of an environment,
and if the SREV1 recalculates the early reflection information in addition to the main
reverb, then that character may be lost. To preserve the character, you can instruct the
SREV1 to begin its calculations after the early reflection information.
Take, for example, an impulse-response data file where samples 0 to 1,000 represent the
early reflections, and samples 1,001 to the end of the file represent the main reverb. By
specifying a reverb start point of 1,001 (e.g., RS=1001), the SREV1 will begin recalcu-
lations after the early reflection information, thereby preserving the character of the
original reverberation.
To specify the RT and RS values in IREdit, choose
Header from the Tools menu. The Edit Header
window appears, as shown here.
Enter a reverb time in the Remarks box in the fol-
lowing format:
RT=xx (e.g., RT=2.0)
Values can be entered in 0.1 second steps.
On a new line, enter a reverb start point in the fol-
lowing format:
RS=xx (e.g., RS=1001)
Value can be entered in single sample steps.
This Remarks box contains both RT and RS values.
