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EQ parts

ArchiverArchiver Posts: 46,084
edited 2003-11-22 23:50 in General Discussion
Hi.

I'm looking for a component (IC or audio component) that can be fed
standard line-level audio signals and will "split" these into multi-band
(7-20) voltages on the output side. Think equalizer. The ultimate device
will feed out 10 or so separate voltages which will be brought into
LM3914 bar graph controllers for output to a multi-segment multi-band
audio display.

I may just buy an old display EQ on ebay, but I'm wondering if there's an
IC-based solution to this?

Sean T. Lamont, Chief Mad Scientist |-- lamont@a...
Zen Chemical Productions |-- http://www.zenchemical.com
Fabricators of Unnecessary Amazement

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2003-11-22 20:20
    I believe a Fast Fourier Transform (FFT) would give
    you this. Is this the right approach? Or are there
    more 'fixed' band circuits that do this commercially?

    --- In basicstamps@yahoogroups.com, "Sean T. Lamont .lost."
    <lamont@a...> wrote:
    >
    > Hi.
    >
    > I'm looking for a component (IC or audio component) that can be fed
    > standard line-level audio signals and will "split" these into multi-
    band
    > (7-20) voltages on the output side. Think equalizer. The ultimate
    device
    > will feed out 10 or so separate voltages which will be brought into
    > LM3914 bar graph controllers for output to a multi-segment multi-
    band
    > audio display.
    >
    > I may just buy an old display EQ on ebay, but I'm wondering if
    there's an
    > IC-based solution to this?
    >
    > Sean T. Lamont, Chief Mad Scientist |-- lamont@a...
    > Zen Chemical Productions |--
    http://www.zenchemical.com
    > Fabricators of Unnecessary Amazement
  • ArchiverArchiver Posts: 46,084
    edited 2003-11-22 23:08
    Yup, most pro-audio editing programs use some sort of Fast-Fourier Transform
    to make this happen on screen, but I would bet a nickel that a Basic Stamp
    doesn't have enough horsepower to manage those calculation in real-time,
    plus drive a bunch of displays. Of course, you could build a bunch of
    band-pass filters (the old analog way) but that seems to be rather complex
    for what you're trying to do.

    Is there a new stamp coming out with that sort of power? Certainly would be
    fun to play with...

    Mike Sokol
    www.modernrecording.com
    mikes@m...

    " One should not increase, beyond what is necessary,
    the number of entities required to explain anything"...
    -William of Occam-

    Original Message
    From: "Allan Lane" <allan.lane@h...>
    To: <basicstamps@yahoogroups.com>
    Sent: Saturday, November 22, 2003 3:20 PM
    Subject: [noparse][[/noparse]basicstamps] Re: EQ parts


    > I believe a Fast Fourier Transform (FFT) would give
    > you this. Is this the right approach? Or are there
    > more 'fixed' band circuits that do this commercially?
    >
    > --- In basicstamps@yahoogroups.com, "Sean T. Lamont .lost."
    > <lamont@a...> wrote:
    > >
    > > Hi.
    > >
    > > I'm looking for a component (IC or audio component) that can be fed
    > > standard line-level audio signals and will "split" these into multi-
    > band
    > > (7-20) voltages on the output side. Think equalizer. The ultimate
    > device
    > > will feed out 10 or so separate voltages which will be brought into
    > > LM3914 bar graph controllers for output to a multi-segment multi-
    > band
    > > audio display.
    > >
    > > I may just buy an old display EQ on ebay, but I'm wondering if
    > there's an
    > > IC-based solution to this?
    > >
    > > Sean T. Lamont, Chief Mad Scientist |-- lamont@a...
    > > Zen Chemical Productions |--
    > http://www.zenchemical.com
    > > Fabricators of Unnecessary Amazement
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2003-11-22 23:50
    Sean

    The NJU7507, NJU7508 and NJU7508 from NJR do approximately what you
    want, but getting ahold of one could be a problem. I'd like to know
    if there are other similar chips out there.

    "Band pass filter for audio spectrum analyzer display". It has an
    analog output for each of 7 to 14 frequency bands, centered from
    about 16khz down to about 40 hz. Internally it is a switched
    capacitor multi band pass circuit clocked at 400khz.

    The '7502 is an 8-pin chip and uses mux scheme for the output.
    There is one audio input pin and one analog output that you feed into
    an analog to digital converter. The output steps through the DC
    level for each band in turn, dwelling for about one millisecond on
    each channel, so you would need a sample and hold or something like
    that to use it with a Stamp. The '7508 and' 7509 are dual channel
    for stereo.

    -- Tracy


    > > I'm looking for a component (IC or audio component) that can be fed
    >> standard line-level audio signals and will "split" these into multi-
    >band
    >> (7-20) voltages on the output side. Think equalizer. The ultimate
    >device
    >> will feed out 10 or so separate voltages which will be brought into
    >> LM3914 bar graph controllers for output to a multi-segment multi-
    >band
    >> audio display.
    >>
    >> I may just buy an old display EQ on ebay, but I'm wondering if
    >there's an
    >> IC-based solution to this?
    >>
    >> Sean T. Lamont, Chief Mad Scientist |-- lamont@a...
    >> Zen Chemical Productions |--
    >http://www.zenchemical.com
    > > Fabricators of Unnecessary Amazement
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