Is phase shifter sombreness?

[Gurner]

Is phase shifter sombreness?

As much as I ponder that one - I just don't know.

It's this guy that poses the question...

http://www.aleph.co.jp/~takeda/radio/phaser/indexE.html

Within that link is his phase shift design assistant.....

http://www.aleph.co.jp/~takeda/radio/psDesigner.swf   (particular note is drawn to 'Calcurate Parameters' ...you really couldn't make that one up)

Anyway, it looks like it might be useful - if I could work out what's going on - any ideas? (ie I can understand the one stage output - centre frequency blah blah ..... but you then get funky up/down triangles appearing when you start upping the stages ....sombreness quotient?)

"But HPF will make my sound jellyfish" - great stuff - bordering on prophetic (I adore his site.....& when you see the level of detail he has gone too...is it any wonder that the Japanese are top of the league wrt electronics goods)

I'm trying to work out how many stages - and the best values I'd need to use - to  shift the full range of guitar notes (82Hz thru 1.3Khz )  from 0 thru 180 degrees.

[PRR]

> funky up/down triangles

What does a phase-chain, mixed with source, do? Peaks and dips. Ups and downs.

Change the number of stages. The number of triangles is always one less. As we may know, one stage won't null, two stages makes one null, 3 makes a dip and peak, and we like 4 stages for a minimally rich dip-peak-dip. 16 stages give 15 dips/peaks so densely spaced that the ear may not hear them well.



First example, 4 stages shows down 412Hz, up 994Hz, down 2.4KHz. I set up the situation in SPICE, it says 412.5, 993, 2,407Hz. SPICE shows more detail of the slope/shape, but you don't have control of that (same for all identical-stage phasers).

> shift the full range of guitar notes (82Hz thru 1.3Khz) from 0 thru 180 degrees

Well, that's easy. You can't get zero twist unless the corner is zero or infinite Hz. Any two stages with corner well above 82Hz and below 1.3KHz will twist most of 180 degrees over the range. But a single 180 deg twist gives one null. And a null does not grab the ear. We really want 360 or more degrees, to go through the null to a peak. We commonly use 4 stages, to get 360 deg midband, 540 (360+180) high end, and 720 deg at infinity.

> full range of guitar notes (82Hz thru 1.3Khz)

I would think the harmonics, at least through the 5th, are an important part of the guitar sound. Much of the interesting stuff off high fret work extends to 5KHz.

[Gurner]

Excellent PRR ....a great explanation - & not a bit of sombreness anywhere to be seen - I guess we can conclude that "No, phase shifter is not sombreness - and no make sound jellyfish"    (& doh, I'd forgot about those harmonics wrt to the guitar's range)

[Mark Hammer]

I guess one has to be fussy about which translation software your use, eh?