DSP Robotics Support

k brown wrote:Oops, nope - the graphics are right, but the Fr controls were backwards/in the wrong place.
Replaced in previous post, also.

OneTen V_v1.001.fsm

On the Vertical layout ... i'm not sure those Shelf graphics follow general standards.

They are correct on the Horizontal layout.

Low Shelf =-- or >--
Hi Shelf --= or --<

excuse for explaining, the sideway V designates how the shelf boosts or cuts.

The graphics are (and were) correct - top knob is high shelf; bottom one low shelf. In the initial post the frequency select knobs were not in the right place. Corrected in the subsequent post (and updated in original post).

Here's what the hardware panel looked like:

Apologies k_b

I was looking at the posted graphics ... the Schematic is indeed correct.

How 'bout n'other?

This one's based on the legendary GML 8200 by George Massenburg, who is credited with inventing the parametric equalizer!

https://www.attackmagazine.com/techniqu ... l-8200-eq/
https://www.theaudiohunt.com/blog/the-p ... rg-gml8200

Two Low bands, one Mid band, and two High bands. The far left Low band, and the far right High band can switch to shelving filters by turning their 'Q' knobs fully CCW (clever idea, George).

The 'INIT' preset approximates the freq and Q settings of the Cello Palette (w/o the 15Hz band), and the 'Cello II' preset approximates the Cello w/o the 500Hz band (the band I use the least frequently).

wooo ... very cool ... and nice looking GUI.

Can't help ask about me doing a mod, though ....

Since you introduced this, I've been doing a lot a testing with this 'CELLO' concept.

Also ... From what I'm reading about this, there does seem to be some discrepancies regarding
Freq choices and Q's [mainly at the extreme ends of the spectrum]. So I experiment with each of them [saved Presets].

As to modding ... that 500hz is, I think, a critical band, and I would like to expand to include it.

My question [please], would it just be a matter of duplicating one of those band 'modules', change the parameter
settings [center freq, q, gain], and insert it into the established serial chain ? Am I missing something ?

Thanks for any insight/guidance ... and thanks again for sharing this concept.

[like me also discreetly mention ... I am currently beta-testing on a up-coming EQ commercial release that has a similar
concept ... from the vintage days. [no ... its' not a FS creation] I can't really say much at this point [non-dis] ... but it is interesting the timing of all this. Once released, I can mention the company name ... they have done some quality product already.

again thanks !

Sure, to add a band, just copy and paste everything.

Awesome work Mr brown...thanks for sharing...

k brown wrote:Sure, to add a band, just copy and paste everything.

cool.

The other thing I notice to add ... the per Band BYPASS. Looking through the previous CELLO schematic to see how you did that.

thanks again !

Annnd . . . this one takes it's cues from the MDW EQ (Massenburg Design Works) plugin that is largely based on his 8200 hardware EQ.

It's contains Martin's complete Matched Filters set (and then some) x5.

The filter types in each band are the same* as in the MDW EQ - 13 in bands 1 and 5; 9 in the other three.



*The resonance behavior of the 'Lo Shelf HiQ' and 'Hi Shelf HiQ' (2-pole) filters are different from those in the Massenburg Plugin - at cutoff there is both a peak and a dip - the MDW has only a dip on the toe; no peak on the shoulder.

Earlier in the thread, it came up that there was a 'mystery' position on the boost/cut switches of the Decca EQ, marked 'R'. Nobody really came up with a very likely theory of what that might have indicated.

Well, out of the blue, the fellow that restored the WSW/Siemens mixing desk that contained those EQs PM'd me on Gearspace and offered to e-mail me the details on that.

Turns out that with the switches in that 'R' position, the high and lo shelf filters become hi and lo pass filters, and the peak/dip filters become sharp-notch cut-only filters! Very clever use of only four knobs.

Still a complete mystery as to choice of the letter 'R' - he didn't know either. Unfortunately he also didn't know the slopes of the hi and lo cut filters or the width of the notches. So I've made an educated guess, given that these were designed exclusively for use on Classical music, to go with gentle 6dB/oct on the hi and low cuts, and Q of 2.5 @ -4dB for the notch filters, as that looked like a shape similar to common peaks in professional condenser microphones.

Just wrapping up these additions to the latest version of the EQ, which I'd dubbed 'Sophie', after the Sofiensaal in Vienna, where the Decca desk was installed. I'll post it soon, maybe tonight.