High pass filter?

[Michael Case]

Forgive my ignorance, I've never been a tech head. Even when I played BG I'd just plug into an amp turn some and turn some knobs until I heard a sound I liked. With the DB I feel like I should have a little more knowledge about these things. Could some explain what the High Pass Filter does. I have a Fishman Pro Platinum EQ does that have an HPF? If so Where?

Thanks again for your answers in advance,
Mike

[mje]

A high pass filter does what it say, pretty much- it only passes frequencies that are higher than some preset frequency, and blocks any that are lower.

You might say, hey, I'm a bass player- why would I want to cut out low frequencies? But your bass can produce signals that are below the fundamental note of your E string, whether from room noise, impact, feedback, or some other source of low frequency noise.

If those low frequencies are amplified, they can feed back, and drive your speaker cone to its limits, possibly damaging it. They can also muddy your sound, by mxing with the frequencies you do want amplified, and they can rob power. This isn't as big a problem with BGT, as it doesn't have a huge surface that can vibrate at very low frequencies.

So a high-pass filter can be a handy thing to have.

[Michael Case]

Very cool, thank you for the explanation and for keeping it in a language that I can understand. So the HPF is built in and preset, I don't have to make any adjustments?

[bolo]

I think in most cases you can adjust the cut-off frequency for the filter either up or down by turning a knob or a slider.

I don't have the Fishman, but I think on that unit it's the 'Depth' knob. The Fishman web site calls it a "low cut" filter, versus "high pass" filter. Same thing.

You will probably want to try adjusting it in different rooms or with different input sources so that it cuts the "boom" or the "flab" from your sound without taking out too much "meat."

Don't you love using words to describe sound?

[Michael Case]

I was beginning to see that the depth knob is the HPF, it's description in the manual matches what I've been told here about the function. So that's cool, I'm now slightly more informed. Thanks guys your answers shed a lot of light on something I really didn't understand.

Yeah using words to describe sound is fun, and strange at times.

[drurb]

Check here as well.

[bloodyjack]

here is the schematic for the fishman pre-amp depth knob I know because I reverse engineered it

[Keyser Soze]

Originally Posted by bloodyjack

here is the schematic for the fishman pre-amp depth knob I know because I reverse engineered it

You go, girl!

Man, I swear, we're all crazy!