I know that by stuffing a box with fiberglass or fiber fill that it will behave as a larger enclosure to the drivers...but at what density does the added volume of the stuffing or dampening material start to have to opposite effect?
I have some 2" acoustic cottong batting that I am going to use to prevent reflections from any of the rear surfaces in my speakers and I just want to be sure of its impact. The measured density of the batt is 3.15 lbs / cu ft at 1.75" thickness. The density of raw cottong is around 95 lbs / cu foot....will my material make the box seem larger or will I go the wrong way?
Thx
I have some 2" acoustic cottong batting that I am going to use to prevent reflections from any of the rear surfaces in my speakers and I just want to be sure of its impact. The measured density of the batt is 3.15 lbs / cu ft at 1.75" thickness. The density of raw cottong is around 95 lbs / cu foot....will my material make the box seem larger or will I go the wrong way?
Thx
I ran a single point cotton batting stuffing trial in a 0.62 cu. ft. AS speaker box. The stuffing was the type sold in craft stores.
I came within a few hz of FG results with a density of 0.65 lbs/cu. ft.
Fs=72 hz, Qtc = 1.3
I suggest you get a base line reading of box resonance and Qtc with no stuffing. Then go ahead and stuff.
Just know there is no magic formula for optimizing box stuffing. Maybe my results will give you a starting point.
I came within a few hz of FG results with a density of 0.65 lbs/cu. ft.
Fs=72 hz, Qtc = 1.3
I suggest you get a base line reading of box resonance and Qtc with no stuffing. Then go ahead and stuff.
Just know there is no magic formula for optimizing box stuffing. Maybe my results will give you a starting point.
Would this still apply of only using the cotton batting for mitigating rear reflections? I only plan to line the walls that are directly behind the drivers, the "stuffing" will be added in a second step?
Most likely something else...these batts seem to be more suited to making panels than being ripped apart for stuffing.
I suppose you know that FG has been found to be the best box volume enhancer. However, if you have an aversion to FG, I suggest crimped PET at a density of about 0.8 lbs/cu. ft. That will finish stuffing the box pretty good.
I'm of the opinion simply stuffing an AS box with any effective stuffing material to a good density that enhances the box volume and provides some critical damping to the woofer response (e.g. reduced Qtc), you will get the internal reflections damped as well.
I'm of the opinion simply stuffing an AS box with any effective stuffing material to a good density that enhances the box volume and provides some critical damping to the woofer response (e.g. reduced Qtc), you will get the internal reflections damped as well.
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