My marshal Accoustic amp

[paulaitchison]

i have a 50 watt marshal accoustic amp, and it sounds amazing, however im having some problems with feedback at high levels.

ive ordered a feedback buster but i need to learn how to use the controls.


it has two anti feedback controls, but i have no idea what to do or how to use them.

anyone know about this sort of thing??

[sfmartins]

With my fishman blender, which has a notch filter I just play my low E string open, then the F, F# and so forth, until I find the feedback. Then I just adjust the notch until that frequency is eliminated (just rotate from 0 to max freq until you're there).

I think the instructions manual of the amp should mention about that. Take a look if you have it.

Works quite nice if the volume is not too high. In that case I don't know if there's much you can do...

[paulaitchison]

so what is feedback
,

i noticed the other day that it didnt like g chords or notes, is it only at a single note where feedback occours?? i thought it was jus the whole guitar vibrating ???

[sfmartins]

Feedback is when a ressonance occurs. By definition, a ressonance happens when a frequency is "feeded" by a force with the same frequency.

Thus, when you play a single note close to the amp, the sound wave emmited by it can interfere with the wave propagating inside your guitar and will "feed them". And it can even "feed" the string vibrating with that frequency.

Now, this can happen for a lot of frequencies at the same time and the "all guitar will be vibrating", but usually it happens only for certain frequencies.

The notch filter cuts a precise frequency (or probably a narrow band), to avoid the ressonance.

Hope this helped!

[mangold]

That helped me too... too bad i don't have a notch filter..

[paulaitchison]

how good are these feedback busters,

it said on the site dave uses one so as not to drop a pick into the guitar.

will that help much?

,apparently i was in the wrong forum

PS, Find Robert Langdon

[sfmartins]

The feedback buster doesn't let the air inside the guitar come out, nor the outside vibrations go in, so it should significantly decrease the ressonance.

However, it does not stop the vibration of the strings, nor the vibration of the wood, and that will "feed" back into the mic/pickup...

[paulaitchison]

i dont know which i have, its a sort of hmhmhmhmmmmmm sound that only happens when im not playing , but when the strings are open

[sfmartins]

i dont know which i have, its a sort of hmhmhmhmmmmmm sound that only happens when im not playing , but when the strings are open

I think the reason this happens is the same as usual feedback:

1. Pick-up gets a given signal (even if you don't play, there is always a small string vibration) and sends it to the amp

2. The amp reproduces the signal sent by the pick-up. It is very low, because there is not much string vibration

3. Now the frequency sent by the amp is the frequency of small vibration of the strings. This will "feed them", and their vibration amplitude increases

4. This is caught by the pick-up again and it just goes back to step 1.

I don't know other way to solve this, besides putting your hand on the strings...

[mangold]

i dont know which i have, its a sort of hmhmhmhmmmmmm sound that only happens when im not playing , but when the strings are open

I think the reason this happens is the same as usual feedback:

1. Pick-up gets a given signal (even if you don't play, there is always a small string vibration) and sends it to the amp

2. The amp reproduces the signal sent by the pick-up. It is very low, because there is not much string vibration

3. Now the frequency sent by the amp is the frequency of small vibration of the strings. This will "feed them", and their vibration amplitude increases

4. This is caught by the pick-up again and it just goes back to step 1.

I don't know other way to solve this, besides putting your hand on the strings...

that aint feedback buddy thats a grounding issue when you touch the strings you ground them because you are much bigger than the guitar

what guitar and pickup are you using?

[sfmartins]

i dont know which i have, its a sort of hmhmhmhmmmmmm sound that only happens when im not playing , but when the strings are open

I think the reason this happens is the same as usual feedback:

1. Pick-up gets a given signal (even if you don't play, there is always a small string vibration) and sends it to the amp

2. The amp reproduces the signal sent by the pick-up. It is very low, because there is not much string vibration

3. Now the frequency sent by the amp is the frequency of small vibration of the strings. This will "feed them", and their vibration amplitude increases

4. This is caught by the pick-up again and it just goes back to step 1.

I don't know other way to solve this, besides putting your hand on the strings...

that aint feedback buddy thats a grounding issue when you touch the strings you ground them because you are much bigger than the guitar

what guitar and pickup are you using?

Maybe the initial vibration comes from a grounding issue, but then a feedback is built up, since you can clearly see the strings vibrating.

[paulaitchison]

im using a tackamine Ean-10, with the tack expression systems pick ups, , its good but i get feed back a high levils (i mean really high, like playing to be heard against full drums 5 feet away)

[matonfan101]

so what is feedback
,

i noticed the other day that it didnt like g chords or notes, is it only at a single note where feedback occours?? i thought it was jus the whole guitar vibrating ???

Trying micing a speaker that your mic is playing through and you'll get feedback.

[TimmyJ4140]

I also play through the Marshall AS50R in a live band rehearsal setting, and my feedback buster works wonders. The filters on the amp just weren't cutting it, and the feedback was killing me, so I dropped the 6 bucks on the feedback buster. Problem solved.

[GuitarGuy305]

Ask the drummer to ease up on it a bit.