[sdiy] Flanger???

[Gene Stopp]

I myself am on the quest for the ultimate flanger. I have not found it yet.
This of course only increases my determination.

Some years ago I wanted to prove that I had a good understanding of the
thru-zero effect. This is what you hear on such recordings as "Life in the
Fast Lane" by the Eagles, or "Killer Queen" by Queen, or countless Tomita
albums.

Experiment #1:

The experiment that I did consisted of a CD player and a Teac 2340. I
recorded a song from a CD (IQ's "Living Proof") onto the tape deck. Then I
rewound, and started both the tape deck and the CD player (boombox)
together. The two sources were coming out of separate speakers - boombox and
room monitors - so the mixing was happening in the room air. After some tape
slowdown manipulation, I was able to achieve the thru-zero effect. It was
enormously profound. Exactly what I was after. But I want this effect on
*my* music, not somebody elses!

Experiment #2:

I built a thing I called the "Gnarlo-Flange" (it says so on the panel) using
two separate 4096-stage BBD's (MN3005's I think). It worked, but it's too
noisey (surprise, surprise, right Harry?). It did not provide the profound
effect I was looking for. It does however do a great job getting white noise
to do the

"whoooosssshhhheeee"-<silence>-"eeeeoooooowwww"

sound that thru-zero flanging is famous for. So great, got the white noise
thing going now. I'll tuck that into my bag of tricks, but my search
continues.

Recently, I have done the following:

Experiment #3:

Purchased a Digitech Studio 100 because it has two separate tweakable
parallel engines. This was totally based on advertisement and considered a
small price to pay just in case it solved my problem right away. It didn't.
But I still use it, it was cheap.

Experiment #3:

Alesis Midiverb 4 "Through-Zero" patch - results, just OK. Sounds like just
another rack effect. Maybe needs more scrutiny and tweaking, but it did not
have the immediate "That's it!" effect. You know guys, sometimes it's really
HARD getting a nice demo going in Guitar Center or Sam Ash - the guys who
work there are just not sympathetic to your desires. After a while you just
have to go "f at ck it, here's my damn credit card, let me out of here!".

Experiment #4:

Eventide Instant Flanger - bought one off ebay. Nice flanging, no thru-zero
(only one delay line inside). Modified it to add resonance for a nice touch,
but not the Holy Grail I seek. Sits happily in the effects rack now. At this
point I realized that NO commercially-available product was going to give me
an out-of-the-box solution. I would have to get craftier.

Experiment #5:

Yamaha SPX-90 and Teac 2340 in parallel - trial and error with this setup
resulted in the discovery that the record-repro head delay of a Teac 2340 on
7 IPS is about 145 milliseconds. Not bad, not great. By this time I am
thinking that the exact frequency response curves of the two delay elements
(whatever they may be) must be as closely matched as possible so that all of
the cancelling frequencies happen at the same time, with the same
peak/valley heighth or depth, to get the real deal. High fidelity and low
noise are essential to get the complete effect. These two delays were just
not matched.

Experiment #6:

Effectron II from ebay (purchased EXCLUSIVELY for this purpose - I'm getting
serious now) and Yamaha SPX-90 in parallel - okay, but right at the
thru-zero point there is some kind of leakage going on such that you can
still hear the program material as though it is going through a high-pass
filter. This of course ruins the effect and only serves to reinforce my
theory that the two delay elements need to be precisely matched in audio
response. Aliasing battles are bad.

Experiment #7:

Not done yet, but I think it's going to happen soon. Purchase another Teac
2340 to match the one I have, and drive one of them with a home-built
variable-frequency mains inverter driven by a voltage-controlled sinewave
oscillator swept by another LFO.

I am mad, I admit it. I will not be defeated.

Best Regards,

- Gene


-----Original Message-----
From: Happy Harry [mailto:paia2720 at hotmail.com]
Sent: Thursday, May 23, 2002 9:40 AM
To: petergrenader at mksound.com; nihil at torgoth.com;
synth-diy at dropmix.xs4all.nl
Subject: Re: [sdiy] Flanger???


Well as u know I am not a 'friend' of the BBD
(Bucket Brigade Delay) but I wouls check out
Juergen Haible's clone of the Eventide Flanger
"Storm Tide Flanger"... it is probably as good
of a circuit as you will ever find.

A LOT of BBD based circuits suffer from pretty
poor noise performance. (read... 'extremely poor')

Phasing and Flanging are really different. In
Phasing, the notches are not harmonic related...
in Flanging they are. Phasing is usually done with
all-pass filter designs... Flanging is done with
delay lines.

I'd look for some old Delta-Lab Effectrons (for cheap)
if you want flanging.  If you have two delay lines...
you can set one for a fixed, short delay (maybe 1ms) and
vary the other one... allowing through-zero flanging
(a VERY cool effect)

H^) harry


>From: Peter Grenader <petergrenader at mksound.com>
>To: Nihil Chimeraea <nihil at torgoth.com>, <synth-diy at dropmix.xs4all.nl>
>Subject: [sdiy] Flanger???
>Date: Wed, 22 May 2002 21:42:59 -0600
>
>Guys,
>
>After finding that the Analog System's Comb Filter was sort of a bust in as
>far as flanging,  I have been looking around for one and had a crazy idea
>just to modify a store bought guitar pedal with a VC input or two.
>
>Then, I found this circuit on John Hollis' site:
>
>http://www.hollis.co.uk/john/ultraflanger3.jpg
>
>You will see there an LFO on the bottom left which is generating the sweep,
>and figured this is the place to plop in the VC input.
>
>Does anyone have any experience with this particular circuit, or could any
>of you recommend another circuit which would do the job?
>
>A clarification on Analog System's Comb FIlter:  I am not meaning to spam
>one of my fav synth builders, not at all.  Their multi=mode filters are one
>of the sweetest out there. Their Comb Filter did not give the effects I was
>after in flanging or phasing, that's all.  It kind of is an auto Adrian
>Belew generator, as anything going into it tends to sound like Ade coming
>out.  This isn't a bad thing, it just didn't do what I wished, so I swaped
>it for a Doepfer phasor. Am still in need to that all powerful flange
>however.
>
>Let me know and thanks,
>
>Peter
>
>




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