Re: [LAU] Sequencer suggestions?

On Tue, Aug 26, 2014 at 05:20:24PM +0200, Philipp Überbacher wrote: The following patches seem to fix the problem. They remove the (inoperative) per patch DC blocker and add one per voice, just after the oscillators. More testing may be required. --- engine.h.orig 2013-01-13 08:18:49.000000000 +0100 +++ engine.h 2014-08-26 17:18:13.514909324 +0200 @@ -84,9 +84,7 @@ sample_t bps; /* beats per second */ sample_t out1; /* output sample 2 */ sample_t out2; /* output sample 1 */ -#ifdef ENABLE_DC_REJECTION_FILTER - sample_t dcR_const; -#endif + sample_t wdcf; } GLOBAL; @@ -105,6 +103,8 @@ int portamento_sample; /* sample number within portamento */ int portamento_samples; /* portamento time in samples */ int age; /* voice age, in samples */ + sample_t dcf1; /* DC filter state 1 */ + sample_t dcf2; /* DC filter state 2 */ sample_t out1; /* output sample 1 */ sample_t out2; /* output sample 2 */ sample_t amp_env; /* smoothed final output of env generator */ --- engine.c.orig 2013-01-13 08:18:49.000000000 +0100 +++ engine.c 2014-08-26 17:54:29.301481175 +0200 @@ -193,9 +193,7 @@ /* (-3dB @ 20Hz) DC blocking filter */ /* 1.0 - (M_PI * 2 * freq / (sample_t) f_sample_rate) */ -#ifdef ENABLE_DC_REJECTION_FILTER - global.dcR_const = 1.0 - (125.6 / (sample_t) f_sample_rate); -#endif + global.wdcf = 125.7 / (sample_t) f_sample_rate; } @@ -487,6 +485,10 @@ voice->midi_key = -1; voice->keypressed = -1; + /* init dc filters */ + voice->dcf1 = 0.0; + voice->dcf2 = 0.0; + /* initialize moog filters */ voice->filter_y1_1 = 0.0; voice->filter_y1_2 = 0.0; @@ -780,10 +782,6 @@ run_part(PART *part, PATCH_STATE *state, unsigned int part_num) { unsigned int osc; -#ifdef ENABLE_DC_REJECTION_FILTER - sample_t tmp1; - sample_t tmp2; -#endif /* generate amplitude envelopes for all voices */ run_voice_envelopes(part, state, part_num); @@ -842,19 +840,6 @@ if (state->delay_mix_cc) { run_delay(get_delay(part_num), part, state); } - - /* output this sample to the buffer */ -#ifdef ENABLE_DC_REJECTION_FILTER - tmp1 = part->out1; - part->out1 = part->out1 - part->dcR_in1 + global.dcR_const * part->dcR_out1; - part->dcR_in1 = tmp1; - part->dcR_out1 = part->out1; - - tmp2 = part->out2; - part->out2 = part->out2 - part->dcR_in2 + global.dcR_const * part->dcR_out2; - part->dcR_in2 = tmp2; - part->dcR_out2 = part->out2; -#endif } @@ -1300,6 +1285,12 @@ run_osc(voice, part, state, osc); } + /* apply DC filters */ + voice->dcf1 += global.wdcf * (voice->out1 - voice->dcf1); + voice->out1 -= voice->dcf1; + voice->dcf2 += global.wdcf * (voice->out2 - voice->dcf2); + voice->out2 -= voice->dcf2; + /* oscs are mixed. now apply AM oscs. */ for (osc = 0; osc < NUM_OSCS; osc++) { if (state->osc_modulation[osc] == MOD_TYPE_AM) { -- FA A world of exhaustive, reliable metadata would be an utopia. It's also a pipe-dream, founded on self-delusion, nerd hubris and hysterically inflated market opportunities. (Cory Doctorow)