Which is the last (outmost) dosbox-contained function you are using?

At the end of dbopl.cpp, in Handler::Generate, it calls MixerChannel::AddSamples_m32(). I have implemented my own version of this function (so that I didn't have to modify dbopl.cpp), which means I receive the buffer that was ultimately filled by DBOPL::Chip::GenerateBlock2().

That's pretty much the final output in mono samples or when it's using generateblock3 it's creating stereo output. It's just the 16bit values of all the different opl channels added up and it depends on the mixer to the final clipping although i don't think the volume is very loud that it even needs clipping.

Ok then, so the mixer must be doing some amplification of its own? The DOSBox OPL output is at least 3-4 times as loud as the output I'm getting, when I treat the samples as 16-bit values.

Any idea what sort of amplification the mixer does? The reason I ask is that I've never heard the DOSBox output clip, but (in the past with other synths) amplifying it myself has always resulted in loud clicks on certain songs when clipping has occurred.

Also as a side note, how are the samples internally generated? Having recently connected an OPL2 chip to an Arduino I discovered the chip outputs digital samples in a weird kind of encoded 8-bit, which the DAC chip then converts to analogue. Does the emulator generate the encoded 8-bit samples internally, or the final 16-bit sample?

adlib.cpp does a mixerChan->SetScale( 2.0 ); (think that's to rebase opl synth with SB digital output)

but (in the past with other synths) amplifying it myself has always resulted in loud clicks on certain songs when clipping has occurred.

How are you clipping? In dosbox the mixer buffer is Bit32s work and it is fed to SDL through
MIXER_CallBack which is also where the Bit32s is clipped down to a Bit16s (SDL target format).

Harekiet may (or may not hehe) remember if all the mixer shifting introduces some amplification.