Crazy resonation

[Kaoskadosk]

So I've encountered quite an issue. The problem I have is that the 7th fret, on the 6th string (B) causes some mad bass resonation in the guitar, and it's only the B note on that specific string. If I plug it into my 5.1 surround it creates this wall of bass making it even more evident. Anyone who has a clue what might be causing it?

 

[AutoBat]

Sounds like you found the harmonic of your guitar and/or walls.  My current apartment likes to resonate at the D string 2nd fret (or 7th on A, or 12th on E)

 

[dNA]

you have discovered a standing wave.
http://en.wikipedia.org/wiki/Standing_wave


Basically what you have is two parallel surfaces whose distance apart is very close to wavelength of a particular note/frequency. What occurs is the soundwave doubling back over itself in unison, reinforcing the note and making it much louder.

if we wanted to do the math, we could probably approximate the wavelength in question. If you did that, you could then measure the distances between parallel surfaces (opposing walls or the floor and ceiling) and probably figure out which surfaces are creating this standing wave. Acoustic treatment could then be applied if you wanted to.

 

[Super Turbo Deluxe Custom]

There was a venue I played at, I could always count on a fretted A on the low E string rattling my teeth like you described and for the reasons everyone else has mentioned.  My guitar player at the time knew the frequencies of where each note like to hang out.  I just cut said frequency on the amp EQ, good to go.

 

[Kaoskadosk]

As AutoBat said, it's the guitar most likely, because I get the same effect when I use headphones. Putting it through my 5.1 just takes it a step further by  making my whole room vibrate.

 

[Super Turbo Deluxe Custom]

Of course it's the instrument.  :icon_scratch:

Boosting or cutting a frequency to create a desirable sound is what the EQ is for.

 

[Kaoskadosk]

Of course it's the instrument.  :icon_scratch:

Boosting or cutting a frequency to create a desirable sound is what the EQ is for.

Well, with the right frequency just your speakers can create this effect, as dNA said before. With high volumes and no EQ that wall of bass hits if I play a song which has that frequency.  :blob7:

There is a fairly powerful EQ in Guitar Rig 4 so gonna see what I can do to reduce the problem.  :icon_thumright:

 

[Super Turbo Deluxe Custom]

Of course it starts with the instrument.  The amplifier amplifies what the instrument is doing.  By cutting or boosting a specific frequency, you can overcome that.  I've done it.  It's why amps have knobs and no 2 rooms sound the same.  And yes, depending on what is boost or cut, one can create a standing wave with tone shaping where one may not exist with only the instrument.  This is my beef with some sound guys.

 

[Patrick from Davis]

Of course it starts with the instrument.  The amplifier amplifies what the instrument is doing.  By cutting or boosting a specific frequency, you can overcome that.  I've done it.  It's why amps have knobs and no 2 rooms sound the same.  And yes, depending on what is boost or cut, one can create a standing wave with tone shaping where one may not exist with only the instrument.  This is my beef with some sound guys.

No, a standing wave will be a function of the room's dimensions.  You may notice it more or less by eq'ing things, but the eq will only mess with your ears ability to hear the true sound.  Bass trapping a room, and doing it properly, is how you squash standing waves.  Standing waves make mixing things incredibly hard because your position it the room can cause a boost or cut, and from a different set of speakers the mix no longer sounds the same at all.  Go into another room, preferably with drastically different dimensions, and try your set up to see if it happens there.
Patrick

Edit:  OK, you can eq it out of a room if you notch out those frequencies entirely.  But then you don't have part of the sonic spectrum...  

 

[dNA]

Edit:  OK, you can eq it out of a room if you notch out those frequencies entirely.  But then you don't have part of the sonic spectrum...  

this is something of a band-aid and it functionally works well to eliminate the unpleasant resonances. Notch filtering is a staple of live sound engineering, but all that phasing and filtering is part of why live sound never sounds as good as a studio recording

 

[Kaoskadosk]

I managed to pinpoint it down to ~122-127 hz, having the EQ at 125 had the biggest impact and it certainly helped. Of course it screws up the tone somewhat, but rather that than being unable to play a lovely segment that I've come up with.

 

[Super Turbo Deluxe Custom]

Edit:  OK, you can eq it out of a room if you notch out those frequencies entirely.  But then you don't have part of the sonic spectrum...  

this is something of a band-aid and it functionally works well to eliminate the unpleasant resonances. Notch filtering is a staple of live sound engineering, but all that phasing and filtering is part of why live sound never sounds as good as a studio recording

Bingo, and also why certain venues are dreaded.  I would add however, that a good live band experience trumps a studio recording most times.  It goes to show too that fingerboard choices and lam top woods matter little outside the living room and studio.