Search found 34 matches

by pharaohamps
Wed Sep 02, 2015 6:26 am
Forum: Algorithm development
Topic: Slow Random Noise
Replies: 6
Views: 8960

So you're only generating the noise when you finish the counter? Seems like it would make it hard to change the speed of the sample period if you rely on the counter. The way a "real" S&H works is to toggle the sample circuit when desired and then a big cap holds the voltage until it's...
by pharaohamps
Sun Apr 19, 2015 3:02 pm
Forum: Algorithm development
Topic: Interesting aspect of the crossfade function
Replies: 6
Views: 8841

Actually, it doesn't have to match on all sides but the two for the "A" signal need to be opposite and equal to cancel out properly. Do we REALLY need to have them separate? Nah. If you have to scale them separately you can either go in and hand-edit the code or use an SOF in front. Thanks...
by pharaohamps
Sun Apr 19, 2015 7:44 am
Forum: Algorithm development
Topic: Interesting aspect of the crossfade function
Replies: 6
Views: 8841

That totally makes sense to me. Look at a crossfade as being like a mixer in a way, ideally you want to have both signals down 3dB at midpoint and 0dB / -inf dB at either end. The typical mixer stage is this: rdax adcl,0.5 rdax adcr,0.5 ;sum inputs to mono wrax insig,1 ;input sum register Read the l...
by pharaohamps
Sun Mar 08, 2015 10:59 am
Forum: FV-1 software questions
Topic: Documentation bug for LOG on page 37 of the SpinAsm Manual?
Replies: 3
Views: 5916

I've been wrestling with this myself. LOG 0.5, 1.75 is the same as LOG 0.5, -0.25 It LOOKS like the range for this "D" offset value is actually 0x000 to 0x7FF, or just those 11 bits. Anything over 1.9990 or below -2 overflows and starts again. Even though the documentation mentions the sig...
by pharaohamps
Tue Feb 10, 2015 9:01 pm
Forum: FV-1 software questions
Topic: LFO and pot skip routine
Replies: 7
Views: 8817

Slacker, that's a nice bit of code. Thanks for sharing. I've played around with making a square wave starting with a sine or ramp and using SOFS but it takes a lot of them to get something that even approaches a real square wave. Try something like this to really get square - start with the output o...
by pharaohamps
Sun Feb 08, 2015 8:01 pm
Forum: FV-1 software questions
Topic: LFO and pot skip routine
Replies: 7
Views: 8817

Triangle isn't that great for tremolo, sine gives you more of a log response and sounds smoother. If you want to do sine and square, you can use a crossfade to pan between them which is super cool. As DL says, you can get sine and square from the same oscillator with either SOFs (gets you more of a ...
by pharaohamps
Tue Feb 03, 2015 2:02 pm
Forum: Algorithm development
Topic: Delay RAM access methods?
Replies: 6
Views: 8828

I wouldn't get hung up about "original." It's not like you're copy-pasting stuff and it magically works. I've looked at some of your Java code and it makes my brain hurt.
by pharaohamps
Mon Feb 02, 2015 6:46 pm
Forum: Algorithm development
Topic: Delay RAM access methods?
Replies: 6
Views: 8828

Really any time you are moving the delay pointer in real time you've got to do SOMETHING to keep the artifacts down. If you modulate the "servo delay" in SpinCAD, you get sort of grainy sounding artifacts as the pointer moves. If you instead use a straightforward chorus setup such as: mem ...
by pharaohamps
Sat Jan 31, 2015 4:02 pm
Forum: Algorithm development
Topic: Delay RAM access methods?
Replies: 6
Views: 8828

I've been doing some more digging and came across the following: Although a memory pointer can be loaded (ADDR_PTR), and used to address memory, if it is to be clear of audible artifacts, an interpolation must be performed at each sample, as the delay is varied. This normally would mean tearing the ...
by pharaohamps
Thu Jan 29, 2015 9:06 am
Forum: Algorithm development
Topic: Delay RAM access methods?
Replies: 6
Views: 8828

Delay RAM access methods?

I'm working on a program that uses a square wave to access different memory locations. If I just update the ADDR_PTR, I get a nasty discontinuity each time the square wave flips the pointer address. I kind of expect that. The alternative is to use the servo method: cho rdal,rmp0 ;servo ramp0 to corr...
by pharaohamps
Mon Jan 26, 2015 6:23 am
Forum: Algorithm development
Topic: Delay with modulation
Replies: 17
Views: 25136

The "zip" noise is caused by the method used to sweep the delay for modulation. Larry's "servo delay" is really a standard delay with some very clever setup on the address pointer stuff. He uses an OR to intentionally reduce the control input resolution to prevent weird noises wh...
by pharaohamps
Fri Jan 09, 2015 4:30 pm
Forum: Algorithm development
Topic: Using multiple servo delays?
Replies: 2
Views: 6118

Re: Using multiple servo delays?

I believe that will work but remove the "reg" in the second "cho" set, the ramp could update between them and we don't want that, we want them to all see the same value. Makes sense. I always forget about reg. This won't work, the new update value will over write the old one in ...
by pharaohamps
Fri Jan 09, 2015 7:59 am
Forum: Algorithm development
Topic: Using multiple servo delays?
Replies: 2
Views: 6118

Using multiple servo delays?

According to the knowledge base, one of the preferred methods for reading a "sweeping" delay such as a flanger is to use a servo method: skp run,1 ;only establish the LFO on the first sample pass wldr rmp0,0,4096 ;set rmp0 to its widest range cho rdal,rmp0 ;load in the current RMP0 pointer...
by pharaohamps
Sat Nov 01, 2014 2:07 pm
Forum: FV-1 hardware questions
Topic: I2C EEPROM read / write method?
Replies: 1
Views: 5133

I2C EEPROM read / write method?

Frank, how does the FV-1 read the EEPROM? Does it just run through each address (0-511, 512-1023, etc.) and grab the bytes, or does it read in page mode?

On a related note, are the I2C inputs 5V tolerant?

Thanks!
by pharaohamps
Fri Mar 21, 2014 6:27 pm
Forum: Algorithm development
Topic: Noise Generation?
Replies: 3
Views: 6976

Perfect! Thanks!