. These soud examples
examplify the modulation of the warping coefficient . The filter that is being
modulated is a warped IIR (WIIR) filter with the order of 100. Sound Examples: DIGITAL GUITAR BODY MODE MODULATION WITH ONE DRIVING PARAMETER
The following demonstrations were played as part of the presentation at the DAFx-00 conference in Verona, Italy, in December 2000.
The paper related to these demonstrations was published in the Proceedings of the 2000 COST-G6 Conference on Digital Audio Effects (DAFx-00), pp. 31-36, Verona, Italy, Dec. 7-9, 2000.
Henri Penttinen, Aki Härmä and Matti Karjalainen
Helsinki University of Technology, Laboratory of Acoustics and Audio Signal Processing
A warped guitar body filter can be modulated and controlled
through one parameter, the warping cofficient . These soud examples
examplify the modulation of the warping coefficient . The filter that is being
modulated is a warped IIR (WIIR) filter with the order of 100.
Listen to these sound examples through good loudspeakers or headphones:
In the examples below the sound sources are an acoustic guitar with a bridge pickup OR an electric guitar used in the final samples .
Examples 1
to 4 are ACOUSTIC GUITAR EXAMPLES.
BASIC FILTERING Example 1: BASIC GUITAR BODY simulation filtering (*.wav files):
1. A
DRY signal from a bridge pickup on an acoustic guitar
with NO filtering.
2. STATIONARY
body simulation filtering when = 0.756
STEPWISE MODULATION
Example 2: STEPWISE modulation of the guitar body
simulation filter (*.wav files):
In these samples is altered once: 1)
Original value (0.73) to a smaller value (0.68).
2) Original value (0.73) to a larger value (0.77).
When the value of decreases the peceived
size is reduced. When the value of increases the peceived
size is enlarged.
1. STEPWISE
ORIG > SMALLER =
[0.73 0.68].
2. STEPWISE
ORIG > LARGER =
[0.73 0.77].
CONTINUOUS MODULATION Example 3: CONTINUOUS modulation of the guitar body simulation filter (*.wav files):
NOTATIONS: I) =
x Indicates the value of the used warping
coefficient.
II) 
= y
Expresses the peak to peak amplitude of the modified lambda.
1. Sine-wave(1
Hz)= 0.756 = 0.1.
2. LINEAR
SWEEP (0.13Hz) (large triangle) with values from 0.8 to 0.1
and back to 0.8.
3. LINEAR
SWEEP (0.13Hz) (larger triangle) with values from 0.7 to
-0.7 and back to 0.7.
Example 4: Highly flexible continious modulation of the guitar body filter (*.wav file):
1. Sine-wave(4
Hz)= 0.5 = 0.1.
Example 5 to
6 are ELECTRIC GUITAR EXAMPLES.
STEPWISE & CONTINUOUS MODULATION
Example 5: STEPWISE & CONTINOUS modulation of the guitar body simulation filter (*.wav files):
1. ELECTRIC
GUITAR
At the very beginning of the sample a unfiltered a riff
played on an electric guitar can be heard. The second time the
same riff is played basic guitar body simulation filtering is
applied. After this the value of the warping coefficient is modulated stepwise. At
the end of the sample the modulation is sinusoidal and at the
very end a linear sweep can be heard.
2. ELECTRIC
GUITAR: HIGHLY FLEXIBLE MODULATION
In this sample the excitaton signal is the same as for the
previous sample, but here the modulation is more dramatic.
Example 6: STEREO, STEPWISE & CONTINOUS modulation of the guitar body simulation filter (*.wav files):
These samples are the same as exmaples 5,
BUT are in stereo. The value of is sligthly different in
the other channel. The difference in the value producess a stereo
effect, but also affects the perceived location of the sound
source.
1. STEREO ELECTRIC GUITAR
2. STEREO ELECTRIC
GUITAR: HIGHLY FLEXIBLE MODULATION