Which building blocks to approximate this sound?

[Ronan]

From the EMS hi fli thread, I wandered around and found this sound sample of "fuzz sweep" from the Synthi hi-fli.
This sound clip really grabs me by the balls. Is there some combination of effects that I can link to get close to this sound?
I am thinking, distortion with delayed attack plus some sort of formant filter and phaser. Or distortion with delayed attack plus a Gemini dual core phaser?
Would that get close, or are we looking at something else entirely?
Thanks for any comments/thoughts.

[Gurner]

I am thinking, distortion with delayed attack plus some sort of formant filter

I think that would get you close (to my ears it sounds like square-ish wave with a bit of pwm going on) - they've also got some 5ths mixed in with the root notes  (albeit at a lower level)...which also adds to the overall vibe of the sound.

[Ronan]

Thanks, I'm trying to learn a bit from this hifli service notes/schem but its way over my head. Seems there's some square wave/octave action going on in there too.

[Rob Strand]

I haven't checked out he doc.  But I looked at the spectrum.  The underlying signal seems to have intermodulation so a chord through some distort of buzzy distorter will approximate that.   The filtering is a sweep from high freq. to low.  The filter is some sort of comb (which you can get with a swept all-pass like a phaser) combined with a low pass (or maybe a low-pass shelf).   There is no modulation, the modulation is a result of the combs falling in frequency and the multiple peaks passing through the same frequency bands in succession as they filter frequency drops - the span of the sweep is therefore fairly wide.

[Ronan]

Thanks Rob, I really appreciate the info, as I have difficulty relating sounds to the methods that created them. I will attempt to recreate the sound and now have a starting point. Must be some nice gear you have there, or you are good at intepreting the spectrum, or both

[WhenBoredomPeaks]

i think it is a sweeping low pass filter before distortion

kinda like this: http://www.youtube.com/watch?v=bLjYujiWeZw (this is more suited for a vocal like result so it uses formant filter and bitcrush but i think it is the same principle)

[bwanasonic]

If I was trying for that sound with things on hand, I'd probably look to the Line 6 FM4 to provide the filtering / synthy aspect. Maybe driving it with Source Audio Multiwave Distortion. Probably wouldn't be as wet and juicy as that clip. Have you looked at Tim Escobedo's PWM circuit? Also maybe a bit more lo-fi than the clip, but certainly in the synthy vein. Speaking of balls, the old EH BassBalls made for some really nice sweeps.

[Ronan]

Yes, the Bassballs has a lot of possibilities, simple circuit and very effective. I breadboarded it and changed it into a nice touch-wah using just one filter. It is also capable of vocal type sounds if both filters are not tied together.

I did some more reading, the EMS Hifli uses 2 six-stage banks of all-pass filters (phase filters), and from the info everyone is putting in here, and reading the hifli manual and notes, I am guessing the two banks are being swept opposite (meow effect) or together (waw effect). The Hifli front-end with distortion/envelope/added harmonics/octaves feeds those filters. The schematics for the front end aren't too hard to read, but the envelope control which detects start and end of note and other things gets a bit complex. There is another possible alternative in using the EH micro-synth front end which was designed a few years later by the same person. Plenty of food for thought. I ordered some LM13700 to breadboard some phase filters and see what happens. Thanks for everyone's input, much appreciated.