Phase-Change

oddson · 19 Sept 2009

A phase inversion is easy... (multiply by negative one) ...and for sine waves it's equivalent.

But to actually change the phase by 180 degrees of any arbitrary waveform you have to know the fundamental frequency so that you can apply a delay of 1/2 the wavelength.

A lot of stuff that says '180 degree phase-change' really means a simple inversion and for some waves and some uses it's close enough.

MichaelBenjamin · 19 Sept 2009

one other way to change the phase of an audio signal is by iir filtering it. typical phase change filter would be an allpass filter, that doesnt change the sound but only the phase around a specified frequency. but all other iir filters also change the phase at a certain frequency region more or less. you may have a look at tobybears filter explorer, where you can see graphs and phase responses for filters, or other filter design programs.

oddson · 19 Sept 2009

Thanks Mike... I wondered if I should have mentioned filters but I didn't think it through enough.

AFAIK it still leaves you with the problem of needing to know the fundamental frequency if you are looking for a specific amount of phase shift.

And since the phase shift is frequency dependant you won't end up with a perfectly shifted waveform -- just one whose FFT shows the same component frequency mix as the input signal.

mcfadden555 · 20 Sept 2009

Many thanks for the quick and helpful reply. But Unfortunately, I am very new at synthmaker and i do not know how to built it.

Can any of you build a small model osm?

Many Thanks,

musical greetings

MichaelBenjamin · 20 Sept 2009

if you only statically change the phase of an audio signal, you wont hear it. you either need to modulate it or mix it with something else to hear any effect. here is a simple example with 2x allpass that changes the phase of a saw wave at different frequencies and mixes the result back together.

mcfadden555 · 23 Sept 2009

Thanks MichaelBenjamin and oddson, for the fast helping support

This is exactly what I need for my project, 🙂

I have some other questions, but not about the topic Phase-Change. I hope it is ok that I change the theme.

My Problem is that I do not understand what are the practical functions / the use of the standalone application (exe), cause:

1. There is no I/O Setup, (bad for live and studio) 2. No Rewire (to link with host) (or can i use propellerhead rewire ? ) 3. I can built a Wave Player in my Standalone exe, but can the signal/wav file be saved to hdd, after edited/processed with my fx?

I would like to use the Standalone option, but i can't find a good solution.

What are our opportunities ?????????

For me, the solution with the wave player would be very good.

Thanks, musical greetings, 🙂

robrokken · 24 Sept 2009

I have the audio outs, ported to my amp, so I use standalones all the time, Record or play di into computer, and export to the amp. Make sure when you are making an exe too, that you add asio ins and outs, in the osm

~Rob.