Yamaha PSS-680 PortaSound Authorized Product Manual page 32

The attack rate for the carrier envelope is set to its maximum
value, 63. This means that the carrier level peaks immediately
when a key is pressed. Now set the value to 01 and press any
key, holding it down for several seconds. Notice how long
it takes the volume to reach its peak.
The two things you can learn from this are:
a) The higher the ATTACK RATE value, the faster the
attack.
b) The carrier (OPERATOR 2) level determines the volume
of a sound.
Reset parameter to the original value of 63 and switch
to parameter the ATTACK RATE for the modulator.
Again, set it to 01 and press a key for several seconds. This
time, the volume remains more or less the same, but the
brightness of the sound increases with time. Lesson three
therefore says:
c) The modulator level influences the tonal quality of a
sound.
If you set the modulator attack rate to around 22, you can
achieve a kind of "wah" effect - try it. Store this new voice
in BANK 2.
To verify that the modulator (OPERATOR 1) is responsible
for the tonal quality, set MOD. LEVEL
sound is the same as the original SINE WAVE voice — even
though operator 2 attack is set to 22, there is no longer any
wah effect since there is no modulation.
DECAY RATES
Recall the voice in BANK 1 by pressing that button. We
will experiment with the DECAY RATES, starting with the
one for the carrier — so call up parameter
Raise the value to around 25 and play some keys. What
sounded like an organ until now has begun to sound like a
clavinette, because
d) the higher the DECAY RATE value, the faster the decay.
In the case of the carrier, this means the sound will die out
faster if you raise the decay rate. While a voice with a carrier
decay rate of 00 will continue "for ever" (as long as you press
a key), high values just produce a short click noise — the
sound dies out so quickly that you do not perceive it as musical
any longer. Try and see, then set the value back to around
25.
Now change the modulator decay, parameter
As was to be expected, this alters-the tone over time. Raise
the value to around 30, and you will get an effect similar to
plucked strings or a percussive instrument being hit by a
mallet. Save this new voice to BANK 3.
By now, you will probably realize the great potential the
PortaSound PSS-680 gives you for creating a wealth of in-
strument or fantasy sounds, using the voice parameters and
your own imagination.
28
FREQUENCIES
Operator 2 Frequency - Parameter
To understand the next parameters, FREQUENCY, again
switch to the SINE WAVE voice 99 and call up parameter
is set to the standard pitch where the frequency of A3 is 440Hz.
Raising the value to 2 doubles the frequency, so all keys play
an octave higher.
Since doubling the frequency of the carrier is the same as
raising pitch by one octave, you have to increase the FRE-
QUENCY value to 4 (NOT 3) when you want the sound to
be higher by 2 octaves, to 8 for 3 octaves. By the same token,
a value of 6 produces a pitch an octave above that of value
3, and an octave below that of 12. The only exception to this
rule is the value 00, which gives a pitch one octave below the
standard.
Operator 1 Frequency - Parameter
Though parameter
same way, only for the modulator, the effect is very different.
Remember that altering the ratio between the two sine waves
of OPERATOR 1 and OPERATOR 2 results in different
wave forms (p.26). This allows you to create various complex
harmonic structures (and thus characteristic tones), which
back to 00. The
depend on the wave form.
Press BANK 3 and access parameter 4. Raise the value to
7. The sound takes on a new quality, becoming "glassy". Store
this voice in BANK 4.
Using the same method, you can also alter the BANK 1 sound.
Call it up and raise its modulator frequency value (parameter
4) to 3. Save this voice to BANK 5.
FEEDBACK LEVEL
on the display.
There is one more parameter that influences the character-
istics of a sound: FEED BACK LEVEL. As you can see in
the front panel illustration, OPERATOR 1 is half surrounded
by a line that leads from its output to its input, marked FEED
BACK
operator 1 output is returned to the input, producing
"self-modulation".
The effect is similar to, though often more extreme than what
would happen if operator 1 were being modulated by another
operator. In other words, increasing this feedback = self-
modulation makes the sound brighter, sharper, etc., just like
as well. modulation of operator 2 through operator 1 does.
Call up the BANK 1 voice and raise its FEED BACK LEVEL.
A setting of 6 produces a distortion or "fuzz" effect, a lower
one of about 4 gives a harmonium-like quality to the original
sound. Choose the setting you like and store the new voice
in BANK 1 again, thus erasing the previous one.
TOTAL LEVEL
Since MOD. LEVEL was explained at the beginning, this
leaves the simplest parameter of them all — TOTAL LEVEL.
It determines how loud voices will sound, allowing you to
adjust the basic volume individually for each voice you create.
Its value is 1. With the PSS-680, this means the keyboard
alters the frequency in exactly the
. This is a "feedback loop" where part of the