[Harp-L] Re: Low and High Pass Filter to fight feeback?

[Mike Fugazzi <mikefugazzi@xxxxxxxxx>]

In general, I have little experience with the filters.  I don't really
have access to them at this point.  In reading about mixing vocals and
bass, though, they get brought up.  I thought maybe if harmonica noise
went form x to y frequencies  and feedback occurred lower or higher
than that, it would work.  I think of the low end feedback that can
happen and thought maybe it came from a lower range than harp hits
anyways.  I readily admit to knowing very little about this.

Thanks for the info!



On Feb 9, 11:18 am, Richard Hunter <turtleh...@xxxxxxxxxxxxx> wrote:
> Mike Fugazzi wrote:
>
> <Anyone ever use these?  If so, at what frequencies?  I am assuming a
> <decent amount of bass and high end feedback rings at frequencies that
> <actually don't matter to the sound of the harmonica.  In otherwords,
> <when played, the harmonica doesn't even reach that low or high of a
> <sound.
>
> "Filter" is another name for "EQ."  A low pass filter cuts out frequencies ABOVE a certain point (thus allowing  low frequencies to "pass" through), a high pass filter cuts out frequencies BELOW a certain point.
>
> Harmonica puts out a LOT of energy in the frequencies from 8 kHz and up, and it's usually useful to cut those frequencies back with whatever EQ you've got in order to reduce high-frequency content that will make the audience's ears bleed, even if the mic isn't feeding back.  (I have killed a lot of small animals in my time with high notes that were well below the feedback threshhold.)  But if you're using a bullet mic and a tube amp, you don't need to worry about it, because a bullet mic and tube amp combo produces a very steep dropoff in energy after 6 kHz.
>
> Below 100 hZ, most harmonicas are putting out breathing noise and not much else.  However, cutting EQ at 100 hZ on a typical mixer may also reduce surrounding frequencies in the 200-250 hZ range that contribute a lot to the tone of an amped harp.
>
> Another poster wrote that he gets feedback issues mostly at 800 hZ, and that makes sense to me.  When I check the tones I get from my Digitech amp modelers on a frequency analyzer, I see a LOT of energy in the 600-1000 hZ range.  It's easier to deal with that kind of thing with a graphic EQ, as opposed to a high or low pass filter.  I suppose you could use a band pass filter (an EQ that reduces frequencies on either side of a specific range), but why bother?  You'll sound like you're playing through a telephone, which is cool sometimes but far from always, and most feedback tends to originate in very specific, relatively narrow frequency bands, which is exactly the problem that a graphic EQ addresses.
>
> Regards, Richard Hunter
>
> author, "Jazz Harp"
> latest mp3s and harmonica blog athttp://hunterharp.com
> Myspacehttp://myspace.com/richardhunterharp
> Vids athttp://www.youtube.com/user/lightninrick
> more mp3s athttp://taxi.com/rhunter
> Twitter: lightninrick