#25 Postprocessing effect should be independent of device

[Anonymous]

Currently Harmonic Effect and Dueling Synths only work with Emulator 1 (Tatsuyuki Satoh) and Emulator 2 (Ken Silverman) respectively, even though there are no technical reasons for imposing such limit. Similarly, it makes little sense to impose limits on audio quality settings when using emulated outputs, or limiting the effects to OPL2 streams when using emulated outputs. Such limits should be removed when using emulated outputs. In fact, why limiting the effects to emulators? Harmonic Effect can be done in hardware by copying and altering relevant OPL2 data streams before sending original and modified streams to separate OPL2 chips, or unused channels of OPL3 chip (or even 2 OPL3 streams to 2 OPL3 devices with different port addresses); Dueling Synths can be done partly in hardware by sending hardware output to OPL device and emulated output to wave device.

[Adam Nielsen]

There are in fact technical reasons for this limit. It is easy to create two independent instances of the Satoh synth, however the Silverman synth uses global variables so it is not possible to have two instances of it at the same time within the same program (the code is there to do this, but it is commented out because it causes both channels to become severely distorted.) The Silverman synth will need to be extensively updated for this to work. As it is not a very accurate OPL2 synth, there is not much interest in doing so, however patches are welcome.

Yes the harmonic effect and dueling synths can work with hardware OPL chips, but as I don't have access to a system with hardware OPL chips I am unable to implement and test it. Again, patches are welcome.

Dueling synths with emulated and real OPL devices would be difficult as there is an output buffer delay with wave devices but none with OPL devices, so some method would have to be implemented to delay the data being sent to the hardware OPL chip so that both devices are synchronised and notes play at the same time.

I'm not aware of any audio quality settings being limited with the emulated outputs, perhaps you could elaborate.