Ah yes hadn't even thought about that -- good point. Is it very unusual to need mono output? If it's a common need, maybe I'll hack the API to provide a way to do it directly -- does the FluidSynth project accept pull requests for things like this?
--Ien On May 14, 2015 10:57 AM, "CERESA Jean-Jacques ENAC/ENAC" < jean-jacques.cer...@enac.fr> wrote: > Hi > >Adding the two channels seems like the straightforward and more natural > thing to do. > > Really, way 2 is the right way. Has you say,this is the more > straightforward, because even if you choose the way 1, > you solve your initial level problem, but you change the panoramic balance > beetween voices (only in the case if your sound is made from > more than 1 voice). In others word, with way 1 you risk breaking the work > done by the soundfont sound designer !. > > All the best. > > jjc > > > Le 14/05/15, *Ien Cheng *<i...@alum.mit.edu> a écrit : > > Thanks JJC - > > That's all very helpful! > > Adding the two channels seems like the straightforward and more natural > thing to do. > > All the best, Ien > > On Thu, May 14, 2015 at 9:32 AM, CERESA Jean-Jacques ENAC/ENAC < > jean-jacques.cer...@enac.fr> wrote: > >> Hi, >> >> >If this is the correct way to generate mono output ? >> When any audio device (i.e the fluid_synth_write_s16() or another >> device) supplies a stereo (left,right) signal, the right way to transfort >> this signal in a mono signal with the same level is to sum left and right >> part.: Mono signal = left + right >> >> >Could this explain why the volume is low? Because each channel is at >> half volume? >> Let a stereo signal with panoramic at 0 (i.e centered) (Left = 50% level, >> Right= 50 % level). >> If you overwrite left channel by right channel (or the reverse) you lost >> 50% of the initial level >> >> Let a stereo signal with panoramic at -25 % . (Left = 75% level, Right= >> 25 % level) >> If you overwrite left channel by right channel you lost 75% of the level >> !!! >> >> >what other reasons could there be for the volume to be low? >> 1) Of course, the main gain must be at 1 to get a full level of the >> soundfont sample used to synthesize your sound. >> 2)To get a full stero level, not only Velocity must be full (127) >> but also both MIDI CC Expression and Volume need to be full. Both have >> correct initial default value (127 and 100). >> >> >If so, is there another way to general full-volume mono output? , >> Here tow distincts ways: >> 1)If you want to use your way (i.e. the right channel overwriting the >> left channel), you can do this workaround: >> Set a stereo signal with panoramic at +50 % . (Left = 0% level, >> Right= 100 % level), for alls voices of the preset used to synthesize your >> sound. >> >> 2)After calling fluid_synth_write_s16() , for each sample you can do: >> left = left + right. >> >> Which do you prefer ? >> >> jjc >> >> Le 14/05/15, *Ien Cheng *<i...@alum.mit.edu> a écrit : >> >> Hi fluidsynth-dev: >> >> I've got fluidsynth working nicely in an Android app. What I'm doing is >> using the fluid_synth_write_s16 API to generate PCM data that I feed into >> Android's OpenSL ES audio system. >> >> However, I'm running into an odd problem where the volume level is low, >> even with all MIDI velocities set to the max of 127. >> >> I wonder if this is due to the way I'm trying to generate mono output. In >> the parameters to to fluid_synth_write_s16, I've set lout = rout, loff and >> roff to both be 0, and lincr and rincr to both be 1 -- i.e. the right >> channel is overwriting the left channel. >> >> Could this explain why the volume is low? Because each channel is at half >> volume? >> >> If so, is there another way to general full-volume mono output? If this >> is the correct way to generate mono output, what other reasons could there >> be for the volume to be low? >> >> Thanks! >> >> --Ien >> >> p.s. Aere Greenway, if you are reading this, THANKS for your reply to my >> question about SF2/DLS/iOS the other day -- I got the mailing list digest >> and can't reply to your reply directly. >> >> >> _______________________________________________ >> fluid-dev mailing list >> fluid-dev@nongnu.org >> https://lists.nongnu.org/mailman/listinfo/fluid-dev >> >> > > _______________________________________________ > fluid-dev mailing list > fluid-dev@nongnu.org > https://lists.nongnu.org/mailman/listinfo/fluid-dev > >
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