Instruments in Wave consist mainly of Effects, Ornaments, EG, SID and offcourse Samples.
Effects control the Pitch and Volume of Note.
Ornaments control the Note by note steps.
Both these elements can be applied to any given note.
In addition SID and EG provide a means to change the Timbre or Tone of the sound.
So how do we use these elements to create cool sounds?
Well one way is to visualise the sound one is trying to get.
For example a classic drum sound consists of a sort of Noisy Tone that hits the spot.
The physics of a Drum sound suggest it is best reproduced by a rapidly decreasing pitch.
So rapid in fact that Ornaments should be used rather than Effects. However we'll still use an Effect to reduce the volume from maximum to zero.
So set a note in a Pattern around the C-3 to C-4 range, give it a volume of F(15) and assign an Ornament and an Effect like the following.
Now switch to the Ornament. We'll want to decrease the pitch so values should start at +000 and decrease by an increasing amount (Remember Ornament offsets are always relative to the original note). Try the following..
Now switch to the Effect.
We'll need to decrease the volume from 15 to 0 so the drum sound dissipates in time to reach the end of the Ornament sequence. So enter the following..
L PITCH +00
And its as simple as that.
Switch back to the Pattern and press RETURN over the note.
You can vary the sound of the drum by adding noise (in the effect) to create a snare Drum or a Bongo by decreasing the ornament steps so the fall is more gradual.
Violins are an interesting sound to produce because they are generally used for long durations as a background sound. As with drums one must listen to them to realise that they often lye above C-5 and their volume rises and falls much more gradually than other instruments.
New to Wave 1.0 is the expanded Volume Rest which may raise, lower or silence the volume of a channel.
Admittedly before V1.0 volume in patterns was a crude beast to control (given only the ability to set to 0, 4, 8 or 15).
Another aspect of a violin sound is that it may resonate which may either be simulated through EG, SID or a simple slow Vibrato using an effect.
One may also use SID Status or SID Noise with the above Volume Rest method as Version 1.0 supports the combination. This will also provide the resonance typical of violins.
The EG (or Hardware Envelope)is the only device in the AY that can control the sound over time without processor intervention. However (and perhaps unfortunately) the range of changes is somewhat limited.
Firstly we only have one EG available. Furthermore it is only able to produce some very basic Volume envelopes and they always begin at Zero or 15. Also the resolution of the volume steps are still 4 Bit so none of that Jazzy Analogue SID stuff here.
The original intention of the EG was to provide simple control over the course of the volume of a channel it was applied to.
The EG Period (16 bit) controls the duration whilst the Cycle register controls how it will behave.
The cycle register can be set to repeat an envelope indefinately and this is the primary use in WAVE. Since it alters the volume similar to a Sample it can be used with very small periods to produce a reduced range of pitches between C-0 and C-2 depending on the effective waveform chosen. Refer to the Reference section on Pitch & Volume behaviour for a full list.
For example when repeating it can produce Sawtooth or Triangle waveforms. Both of these are supported in Wave and shown in the EGC C column as S or T respectively. The D setting sets the Cycle register to a simple Decay from 15 to 0. This can be useful for spot effects and the extreme Strong Bass effect used in SID examples.
Also note that the Cycle setting in Wave should only be set when the waveform is changed, since each time it is written the hardware of the AY reinitialises the waveform which will sound awkward on rapid changes.
In addition to being given control over the volume the existing chip channel can either remain or be disabled. Combining this square wave with the EG's Triangle or Sawtooth waveforms can produce some very interesting sounds.
Because with either waveform we have at least one complete octave we can utilise the nature of the even tempered scale to produce higher notes by keeping the semitone within an available octave and setting the chip note to a much higher octave.
For example in a Pattern enter the following..
- 29S - C-5 01- - RST - - - RST - - -
- - - - RST - - - RST - - - RST - - -
- 24- - D-5 01- - RST - - - RST - - -
- - - - RST - - - RST - - - RST - - -
- 42- - F-5 01- - RST - - - RST - - -
Now set Effect 1 with the following line at the start..
> EGPER +00
Since volume is being controlled by the EG the volume set in the Patterns is irrelevant.
Now switch back to the Pattern and play it. You will hear that whilst the pitch difference between the Square wave of the Chip channel and the Sawtooth wave of the EG is vastly different it still sounds similar and produces a new sound.
This was demonstrated alot in Yerzmyey's music on the ZXSpectrum and well worth a listen especially in the tunes Voyage and Yerzmix.
In fact Yerzmyey took the technique one step further by using other channels. By creating a melody of interesting chords it is possible that mixing EG can produce some very resonating and cool sounds.