how many notches in a phaser envelope?

[duck_arse]

can anyone tell me, if I feed a tone - A 440 eg - into a phaser, let's say it has 2 stages, and I watch the output envelope as I (try) and find the sweet spot on the trimmer, how many notches is the phaser phasing, and how many is it tremoloing? is there a correlation between # of stages and envelope notches, or is it a bit more frequency dependent?

and does a well tuned phaser swoosh twice per lfo sweep, or only one smooth swoosh per? anyone?

[R.G.]

http://www.geofex.com/article_folders/phasers/phase.html, 1999.

[duck_arse]

hmmm, I did skimm that article earlier, and saved it for further close examination. better re-read it.

[Mark Hammer]

The notches all move up and down together.  Unlike a flanger, where the number of notches increases as it sweeps down, and then decreases as it sweeps up, the number of notches produced by a phaser is fixed.

BUT.....

There is a difference between a notch produced, and a notch heard.  So, while it CAN happen, it is rare that a 4-stage phaser (yielding 2 notches) will ever sweep up high enough that you only hear one of those notches and everything else is out of range.  When it comes to things like 12-stage phasers (6 notches), often the upper notches will be out of the range of what the instrument produces, or above the normal bandwidth of the amplfier speakers.  And if the speakers can't reproduce it, or there is no frequency content "up there" to stick a notch into, then for all intents and purposes it may as well not exist.

So, when it comes to 4, 6, and even 8-stage phasers, you end up being able to hear all notches produced across the full range of sweep.  Once you start to get out beyond 4 or 5 notches, some of those additional notches kind of drop off the radar at the high end of the sweep, returning once the sweep comes back down and all those notches are within range.

I suppose the same logic applies if the unit is tuned too low a well.  I.E., a notch hypothetically produced at 40hz is unlikely to show up while strumming my guitar.

All of THAT said, the fact that a notch can be produced, and is audible, is entirely separate from how much it sticks out.  So, sticking any sort of distortion before a phaser is likely to make the upper mids more pronounced, and so make all notches produced easily heard throughout the entire sweep cycle.

[ashcat_lt]

Note that a pure sine wave won't show you any notches.  If a notch happens to cross the frequency, you'll see it to up and down, but it won't tell you much.  You'll want a noise source into a frequency analyzer to get any useful info.

[duck_arse]

I'll try again, mr timeout post eater .....

thank you posters, I've been misunderstanding a few thinks. I'll go back and try the p45 circuit as originally drawn, and sweep the input this time, see what I get.

mark, I did put a fuzz, and it did give the jet sound I remember dimly from my mate's roland many years ago.

[Mark Hammer]

The most persuasive demos of phasers and flangers are generally those using a broadband noise source.  You listen to those and you immediately think "Man, I have GOT to get me one of them!!".  When you do finally get one and plug in your guitar, it doesn't sound nearly as impressive.  As I'm fond of noting, the majority of classic flanging sounds that make us all want to go out and buy one are those where flanging is imposed on several mixed-down tracks in post-production.  Not exactly the same as white noise, but broad enough, and full enough, in spectral content, that just about every notch is audible.

[R.G.]

In general, for the first-order phase shift sections in most musical phasers, it takes two stages to make one notch. The P45 will have at most one notch if it's correctly set up. The P90 is a two-notch phaser.

And the earlier posts are correct - on a sine wave, it sounds like a tremolo as the phase notch passes the frequency of the sine. You need a harmonically rich signal to hear it well.


... and I was just about to type that wideband noise is the best signal to display a phaser's sound, but it's not musically interesting when Mark's post popped up.