Peaking boost/shelving cut

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NewYorkDave

Well-known member
Joined
Jun 4, 2004
Messages
4,378
Location
New York (Hudson Valley)
I've been farting around with various values of reactive elements in my EQ circuit, and it's occurred to me that for the high and low bands, it would probably be most useful to have a peaking response when boosting and a shelving response when cutting. My reasoning is that when you're boosting treble or bass, you usually don't want to boost out-of-band noise as well. So that seems to call for a peaking response. On the other hand, shelving response is what you want 99% of the time when you're cutting at the ends of the band. So it seems a combination response would yield the most useful EQ with the fewest controls. (I'd like to avoid having a bunch of "peak/shelf" switches in addition to the level and frequency controls, if I could).

Whatta you think?

Oh, by the way, it's not a new idea. Here are the curves of the circa-1961 Langevin EQ-251A:
Curves
The LF curves are shelving, but the HF curves are a combination as described above. The classic Cinema Engineering EQ used a similar circuit and a similar set of curves. (I believe both designs are due to Art Davis).
 
hey dave-

Id actually prefer exactly thhe opposite, peak cut shelf boost. Everyone uses an EQ differently though so thats my two cents. I like to cut out specific junk and boost for effect...

I have a 251 which you can borrow if that would help you at all.

dave
 
Good point... Although this EQ is no "Little Dipper" for surgical work, you're right that everyone uses EQ differently. Perhaps "peak/shelf" switches are a good idea after all.

What do you guys think of this set of frequencies? The mids are peaking, of course, and let's assume for now that the LF and HF and switchable peak/shelf.

LF:
40Hz
100Hz
Plus perhaps 60Hz, peaking only...? (For hummmmmm suppression).

MF:
350Hz
1kHz
3kHz

HF:
5kHz
10kHz
15kHz

When I get the circuit breadboarded, I'd like you and Ytrehalf to check it out, since I think you guys have better-trained ears than I do. Maybe we can get Seth to come over, too.
 
I was thinking about your EQ as well. For me, I would have thrown in a 1. order HP and LP filter. In combination with the shelfing boost, you get something like a peak with variable Q.

Samuel
 
Well im used to my Tubeteck eq, and I like the low shelf boost, and hi peak boost action, but a peak/shelf selector..or a six way rotary with three peak and three shelf would for shure be a good thing. I think you should have more than three mid frequencies to play with ala 1073 or 550 or something...my two kroner :grin:

jo
 

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