'Cello Filter" - Simulation of String Instrument Frequency Curves

[liquids]

So Jurgen Haible posted this plot on his website...it's a plot he re-drew from a book by Arthur Benade, "Fundamentals of Musical Acoustics" 2nd edition 1990, which has some frequency plots for some instruments he came up with such as a cello, somehow.

Jurgen redrew it here...neither the book nor Jurgen have DB references for this filter, just a frequency axis and the curve...but that should be enough, plus ears:

I note the similarity to some guitar speaker frequency plots....?

Anyhow, this is not a synth forum, I realize, but I think a fuzzed out or clipped-out signal fed into such a filter would be interesting to hear just the same.

Jurgens mp3s are 404 direct from the website, but archive.org retained a copy of the mp3 of him comparing a 'raw' sawtooth wave with some vibrato and ASDR, followed by the sound of him running the same sawtooth wave into his approximation of this cello filter in a two minute sample...no idea how long this will archive (so I saved it) but if you link here, it will open a download dialogue to hear it so long as it is archived:

http://web.archive.org/web/20060820135820/http://jhaible.heim.at/string_filter/jh_string_filter_benadecello_cs50.mp3

That said, there is a sharp (And I assume, essential) dip at ~2k that looks to be about -16db relative to the highest peaks on the frequency plot...
geofex.com has a lot of info on generating peaks and such...likewise ROG has a general act+passive implementation for a cab simulator which has some similarities...like...two peaks and a dip...however Jurgen's plot is unique in multiple ways.

I wouldn't be surprised if it weren't a boadload of circuitry just for a finely tuned, static filter...but if anyone has any leads/tips/suggestions, much appreciated as I don't think jurgen ever posted schematics for this particular portion of circuitry.

[Jordan A.]

I remember over at electro music someone asked Jurgen about doing a board for this and he said it was easy enough to do with any old parametric eq so there was no reason for him to make a new project.

I've never spent much time with one but I bet you could get pretty close with the info on geofex.  I know a violin player who uses a graphic eq set up with a curve that looks a lot like that one, interestingly, with the big dip at 2k and all.

Not super helpful, but looks like a cool thing to get into,

jordan

[liquids]

I remember over at electro music someone asked Jurgen about doing a board for this and he said it was easy enough to do with any old parametric eq so there was no reason for him to make a new project.

Yeah...easy enough-for Jurgen Haible!   

I've never spent much time with one but I bet you could get pretty close with the info on geofex.  I know a violin player who uses a graphic eq set up with a curve that looks a lot like that one, interestingly, with the big dip at 2k and all.

Pretty interesting.  Piezos (which I assume said violin player was using, not a mic) are pretty nasty sounding...maybe a piezo on a violin is not that less 'nasty' than a sawtooth. 
You're right - info at geofex should probably get one 'close enough.'  There are only so many parametric EQs out there.  It's just that everytime I sim a tone control with variable frequency and variable width and variable boost cut, nearly EVERY knob interacts with the other.  A graphic EQ makes a lot of sense, but to get a notch that narrow between boosts, you'd need to apprach 15 bands, I'd say.

that said, the narrow but deep dip at 2k seems easy enough via a twin T.  the rest can probably be fugded by adding something between something like a tweaked 'condor' speaker sim - that is, active 12db HP and LPF, and then the controled, more general 'dip' via a passive bridged T like the condor also uses...all done tweaking values with some level of understanding via spice.

This may be an area where 'close' results as achieved from the above approach is "good enough" so long as that big narrow dip at 2k is bit neglected....it's never gonna sound like a cello, but if you have a sawtooth, even and odd harmonics abound, so it's like filtering white noise, in a sense...any EQ shaping will have a big affect if you a/b, but trying to duplicate the exact curve may not only be nearly impossible given all the variables, it may be unnecessary....heck, you can pull of a convincing 'pink noise' and/or 'brownian noise' with nothing but white noise and an r-c filter so long as you aren't a/bing against the 'real thing.'