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Conference napalm::commusic_v1

Title:* * Computer Music, MIDI, and Related Topics * *
Notice:Conference has been write-locked. Use new version.
Moderator:DYPSS1::SCHAFER
Created:Thu Feb 20 1986
Last Modified:Mon Aug 29 1994
Last Successful Update:Fri Jun 06 1997
Number of topics:2852
Total number of notes:33157

2534.0. "Passive EQ???" by WEFXEM::COTE (Can't touch this...) Thu Dec 27 1990 17:51

    I'm in need of some eq. What I'd like is a "passive" eq box, that
    I could put in-line between the audio-out of an SGU and the input
    to my board.
    
    My "ideal" unit would be MONO in/out, 3 bands (Low, Mid, Hi) and
    sweepable mid-points for all three. Q would be cool.
    
    Any ideas? Are such devices available? I've no aversion to rolling
    my own if someone can point me to a schematic...
    
    Edd
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2534.1passive ? not MEKEYS::MOELLERCan I have nodename YPYSCM?Fri Dec 28 1990 14:3114
            <<< Note 2534.0 by WEFXEM::COTE "Can't touch this..." >>>
    >.. that I could put in-line between the audio-out of an SGU and the input
    >to my board.
    
    I know why you want passive.. less hum/hiss.  It's prolly possible, and
    I'm sure you can get some suggestions here.  My question is, why ? 
    I've got an old, used, stereo 10band TEAC graphic EQ.  As all my SGU
    audio outputs hit my patchbay on their way to my mixer, and as the EQ
    ins and outs are also available on the patchbay, it's extremely simple
    to EQ any signal from any SGU or any track(s) on the 8-track, as well.
    And I'm unaware of any added noise to the signal.
    
    karl
    
2534.2Leave It To CraigAQUA::ROSTMy head's in MississippiMon Dec 31 1990 13:075
    I have a circuit for a passive semi-sweepable (ten switchable  center
    freqs) midrange control from Craig Anderton's book "Electronic Projects
    for Musicians" that you're welcome to...
    
    							Brian
2534.3the problem with passive is insertion loss...LNGBCH::STEWARTIt's not broke! It's, uh, modular!Mon Dec 31 1990 13:370
2534.4STROKR::DEHAHNNo time for moderationWed Jan 02 1991 12:056
    
    ...and impedance matching, and output drive capability. But a circuit
    can be built very cheaply and simply.
    
    CdH
    
2534.5DCSVAX::COTEEdd - 9, Mousies, 11Wed Jan 02 1991 12:109
    Actually, what I want is a device to give my drum machine's bass
    drum a little boost.
    
    My board has 3 band eq per channel, but it only feeds the mains. I'm
    using the monitor sends for recording and they come before the eq.
    
    ...sounds like Brian may have the answer....
    
    Edd
2534.6Passive "boosting" Is MessyAQUA::ROSTMy head's in MississippiWed Jan 02 1991 12:469
    But Edd, passive EQ can only cut, not boost.  So to get a boost you
    would have to boost gain overall then cut back the mids and highs, not
    an optimal situation.
    
    Your board has inserts on the channels doesn't it?  Do these come
    before or after the monitor send?  If before, patch in an EQ there. 
    For that matter, you could patch in the graphics from the mains.
    
    							Brian
2534.7I told ya Brian had the answer!!DCSVAX::COTEEdd - 9, Mousies, 11Wed Jan 02 1991 13:094
    Ooooo, yeah! I forgot about the channel inserts! Patching them into
    and out of the graphics may just work!
    
    Edd