Phase Tech problem(small)

[CUBE]

When I listen to music everything is fine but when I listen to movies I hear some type of resonance from one of the speakers. You can only hear this sound on certain voice tones. Could this be from the mid, tweeter or the resonance of the cabinet? Thanks alot. The resonance comes from my mains and the cabinets are about 3/4 inch thick. Thanks again.

 

[jaxvon]

It could be a cabinet resonance. Try playing back a scene where you know the problem occurs and put your hand on the cabinet to see if you can feel any extra vibration.

 

[CUBE]

It could be a cabinet resonance. Try playing back a scene where you know the problem occurs and put your hand on the cabinet to see if you can feel any extra vibration.

That's exactly what's going on, what can I do about it? thanks.

 

[WmAx]

If, in fact, the problelm is an audible panel resonance, you can reduce or remove the audibility of this resonance by modifying the cabinet of the speakers.

The easiest way is to go to Lowe's Home Center, for example, and find a roll of material called Peel-N-Seal. It has aluminum foil on one side, and a highly damped rubberized-asphalt material with adhesive on the other. You will probably need at least 2 rolls if you have floor standers. Remove the drivers and acoustic batting/insulation from the speakers, and then apply the Peel-N-Seal in several layers, equaling at least 1/4 total thickness of the original wall thickness. That means, for example, if your walls are 1" thick, you need to apply layers of the Peel-N-Seal to build up to at least 1/4". Ideally, you probably want to be 1/3 of the total thickness. You can also use Dynamat(a car audio product, and slightly more efficient), but it may cost substantially more locally. The modification is easy, but it is time-consuming. It will take at least 3 or 4 hours, because of the tight space you have to work in, and the Peel-N-Seal is very sticky, and will make cutting harder after it gets your scissors or razor blades sticky during cutting. While you have the speaker apart, you may want to add in more effective internal acoustic batting material; many speakers seem to use sub-optimal amount for midrange resonance supression caussed by the internal reflective surfaces. But this depends on the local availability of such material(s). The Peel-N-Seal, if applied to all internal walls, in the amount I specified, will prevent the enclosure from being able to ring long enough to be subsantially audible. Note: the walls will still vibrate. They simply will not be able to continue ringing after stimulus(which is what is currently happening, and what is probably most audible). When applying the adhesive material, be certain you have an excellent contact to the enclosure walls. Tap moderately with a hammer or use small roller, or whatever you can manage to use inside of the enclosure, and have available, that will apply high force over a small area, to insure a good bond.

-Chris

 

[CUBE]

If, in fact, the problelm is an audible panel resonance, you can reduce or remove the audibility of this resonance by modifying the cabinet of the speakers.

The easiest way is to go to Lowe's Home Center, for example, and find a roll of material called Peel-N-Seal. It has aluminum foil on one side, and a highly damped rubberized-asphalt material with adhesive on the other. You will probably need at least 2 rolls if you have floor standers. Remove the drivers and acoustic batting/insulation from the speakers, and then apply the Peel-N-Seal in several layers, equaling at least 1/4 total thickness of the original wall thickness. That means, for example, if your walls are 1" thick, you need to apply layers of the Peel-N-Seal to build up to at least 1/4". Ideally, you probably want to be 1/3 of the total thickness. You can also use Dynamat(a car audio product, and slightly more efficient), but it may cost substantially more locally. The modification is easy, but it is time-consuming. It will take at least 3 or 4 hours, because of the tight space you have to work in, and the Peel-N-Seal is very sticky, and will make cutting harder after it gets your scissors or razor blades sticky during cutting. While you have the speaker apart, you may want to add in more effective internal acoustic batting material; many speakers seem to use sub-optimal amount for midrange resonance supression caussed by the internal reflective surfaces. But this depends on the local availability of such material(s). The Peel-N-Seal, if applied to all internal walls, in the amount I specified, will prevent the enclosure from being able to ring long enough to be subsantially audible. Note: the walls will still vibrate. They simply will not be able to continue ringing after stimulus(which is what is currently happening, and what is probably most audible). When applying the adhesive material, be certain you have an excellent contact to the enclosure walls. Tap moderately with a hammer or use small roller, or whatever you can manage to use inside of the enclosure, and have available, that will apply high force over a small area, to insure a good bond.

-Chris

thanks alot chris.