[maxmsp] Re: Re: comb~ and alternatives

On 19 Apr 2008, at 22:11, Roth Michaels wrote:
>
>
>> aha, and if you go for distinct pitches, make sure you set the delay
>> time 1 sample shorter than the pitch period you want to obtain.
>
> This suggestion I was not aware of, why exactly should you need to  
> do this?  Is this to make up for some interpolation error?  If you  
> could fill me in that would be great :)
> --

no, afaik this is not linked to interpolation.
we had a little discussion on the chuck-list about that issue not  
long ago.
if you let the user provide the feedback path (as with tapin/tapout)  
you can only access the feedbacked signal one sample later (assuming  
a sigvs of 1). so in case you use the feedback delay to produce  
periodic oscillation, the period will be 1 sample longer than the  
actual delay time specified. i.e. the ringing sounds out of tune.
in an external, with built in feedback path, you can compensate the  
one sample delay and get correct tuning if you pay attention to read- 
write order.
this is what i _think_ it is, as i don't know the inner workings of  
tapin/tapout.
but maybe someone from cycling wants to shed some light it?

well, you can always just test it yourself - see the patch below.

volker.



#P window setfont "Sans Serif" 9.;
#P window linecount 1;
#P hidden message 203 172 69 196617 set 1 1 1 0.5;
#P user gain~ 403 451 24 100 158 0 1.071519 7.94321 10.;
#P flonum 417 275 46 9 0 0 0 3 0 0 0 255 227 23 222 222 222 0 0 0;
#N vpatcher 10 59 610 459;
#P outlet 89 297 15 0;
#P window setfont "Sans Serif" 9.;
#P newex 159 127 21 196617 t 1;
#P newex 159 87 48 196617 loadbang;
#P window linecount 1;
#P newex 89 239 45 196617 - 0.022;
#P flonum 215 185 50 9 0 0 0 3 0 0 0 221 221 221 222 222 222 0 0 0;
#P newex 159 154 66 196617 sampstoms~;
#P inlet 89 89 15 0;
#P connect 0 0 3 0;
#P connect 3 0 6 0;
#P connect 2 0 3 1;
#P connect 0 0 5 0;
#P connect 4 0 5 0;
#P connect 5 0 1 0;
#P connect 1 1 2 0;
#P pop;
#P newobj 417 250 63 196617 p m1sample;
#P newex 417 331 29 196617 sig~;
#P newex 461 410 53 196617 *~ 0.999;
#P newex 461 369 44 196617 tapout~;
#P newex 461 330 65 196617 tapin~ 1000;
#P newex 244 329 29 196617 sig~;
#P comment 101 112 100 196617 delay time;
#P toggle 280 114 22 0;
#P newex 280 144 64 196617 metro 5000;
#P hidden newex 101 78 60 196617 loadmess 3;
#P comment 160 342 48 196617 Hz;
#P flonum 100 129 46 9 0 0 0 3 0 0 0 255 227 23 222 222 222 0 0 0;
#P flonum 100 341 59 9 0 0 0 3 0 0 0 221 221 221 222 222 222 0 0 0;
#P newex 100 314 49 196617 !/ 1000.;
#P user gain~ 100 451 24 100 158 0 1.071519 7.94321 10.;
#P newex 100 362 40 196617 tri~;
#P user led 191 600 17 17 0 150;
#P newex 208 600 30 196617 dac~;
#P user gain~ 212 451 24 100 158 0 1.071519 7.94321 10.;
#P button 280 168 23 0;
#P newex 280 408 53 196617 *~ 0.999;
#P newex 280 206 37 196617 click~;
#P newex 280 367 44 196617 tapout~;
#P newex 280 328 65 196617 tapin~ 1000;
#P comment 146 131 100 196617 ms;
#P comment 48 432 100 196617 test tuning;
#P comment 469 276 143 196617 delay time minus 1 sample;
#P window setfont "Sans Serif" 14.;
#P window linecount 3;
#P comment 419 81 160 196622 make sure your sigvs is set small enough  
(e.g. <= 128);
#P connect 20 0 19 0;
#P connect 19 0 8 0;
#P connect 24 0 29 0;
#P connect 24 0 25 0;
#P connect 16 0 14 0;
#P fasten 16 0 22 0 105 262 249 262;
#P fasten 16 0 27 0 105 241 422 241;
#P connect 6 0 4 0;
#P fasten 6 0 23 0 285 299 466 299;
#P connect 5 0 9 0;
#P connect 5 0 7 0;
#P hidden connect 18 0 16 0;
#P hidden connect 18 0 30 0;
#P hidden connect 30 0 6 0;
#P connect 8 0 6 0;
#P hidden connect 11 0 10 0;
#P connect 29 0 10 0;
#P connect 29 0 10 1;
#P connect 28 0 26 0;
#P connect 27 0 28 0;
#P fasten 25 0 23 0 466 437 535 437 535 317 466 317;
#P connect 23 0 24 0;
#P connect 26 0 24 0;
#P connect 22 0 5 0;
#P connect 4 0 5 0;
#P fasten 7 0 4 0 285 435 353 435 353 315 285 315;
#P connect 9 0 10 1;
#P connect 13 0 10 0;
#P connect 13 0 10 1;
#P connect 9 0 10 0;
#P connect 12 0 13 0;
#P connect 15 0 12 0;
#P connect 14 0 15 0;
#P window clipboard copycount 31;