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antialiased wave forms question

March 22, 2012 | 7:41 pm

Hi all… question:
why antialiased wave forms like saw~ rect~ or tri~ don’t fullfill the scope from -1 to 1 as cycle does? saw~ seems also to have a lil’ offset in minus.

thanks



pid
March 22, 2012 | 8:01 pm

because they are… antialiased. also dc offset built in since max6, so at low hz you’ll see that weirdness.


March 23, 2012 | 1:11 pm

yes… thanks pid… but… i was searching for a more technical explaination about why anti aliased waveforms have to be so, i’ll try to explain better:
i’m multiplying a signal by a choosable waveform, for lfo and ring modulation.
the modulating wave can be saw~ rect~ cycle~ but of course the sig amplitude when using cycle is higher then when using antialiased rect~ or saw~, so i multiplied the rect by 1.5 and the saw by 1.75 and added to 0.7 because of the offset (this are just guessed values done looking at the scope) in this way the amplitudes are similar to when cycle it’s used as mod wave. But of course i thought there should be a reason why antialiased waves have to have less amp or offset, and if i would know this reason i could decide if the multiplying process of them is good or bad for my needings.


March 23, 2012 | 1:45 pm

You may have noticed that the antialiased waveforms don’t really look like the ideal waveforms, so if you’re trying to make a LFO that has a modulating effect that sounds similar to the ideal shape, maybe you want to use the ideal shape, perhaps with just a bit of smoothing to avoid clicks. Here’s an example that uses about 1 ms of smoothing time when the ideal waveform jumps from 0 to 1 or 1 to 0.

– Pasted Max Patch, click to expand. –

March 23, 2012 | 2:28 pm

my doubt was more around ring modulation (i wanted to use the same waves for both low frew mod and high freq mod) that’s why i preferred to use antialiased waves, and the probleam as i said was the difference of amplitude between modulation with cycle and modulation with saw~ rect~ etc… i’ll try to cut the interested piece of patch and post it to make clear what i mean


March 23, 2012 | 2:48 pm
– Pasted Max Patch, click to expand. –

March 23, 2012 | 2:50 pm

my first error is of course that i wanted to use the same antialiased waves both for ring modulation and lfo when i should use other waves for lfo but the question about amplitude of antialiased waves remains the same… look patch above


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