Reading through some people's builds and recomendations I came across people adding a SIGNIFICANT amount of weight into their enclosures. On the order of 50-100 lbs.
I saw the saying "double the MMS" multiple times like its some sort of rule of thumb.
I have some plate steel sitting around doing nothing. I could add it to the bottom of the cabinet but does that actually make a difference?
I saw the saying "double the MMS" multiple times like its some sort of rule of thumb.
I have some plate steel sitting around doing nothing. I could add it to the bottom of the cabinet but does that actually make a difference?
FYI/FWIW: I mentioned this WRT a horn speaker cab that weighs at least ~160 lbs (can't remember its actual average weight since it varied depending on design specifics), which at a glance seems pretty moot, but an AUB/HESA forum member took me to task, so to speak and proved me right:
Mass loaded VoTT A7 (AUB forum)
Mass loaded VoTT A7 (HESA forum)
Mass loaded VoTT A7 (AUB forum)
Mass loaded VoTT A7 (HESA forum)
As to bottom only, not too much IME compared to on top beyond good floor coupling (a bad thing IME WRT 'floating floor' design if very low tuned)
The bricks added a considerable amount of frontal area to the cabinets, which would have more of an acoustical effect than the weight.
An woofer with unusually high MMS (moving mass) would be in the 500 gram range, moving as much or more than 50mm peak to peak.
Adding one kilogram to a cabinets weight wouldn't have an appreciable effect.
The Altec drivers in GMs links have a tiny fraction of that moving mass.
Very heavy drivers forward and back movement can cause a lightweight cabinet to shake, and that shaking may be out of phase with the driver's output. If the weight is sufficient to stop the cabinet movement, it can increase output level and smooth the frequency response.
Adding mass won't hurt anything, but probably won't have much effect either.
OK, seems like it isn't worth my time at this point. If anything, I can weld up some stupid heavy stands later that will mount to the bottom and add some character, and weight, to the build
In principle it's called Conservation of Momentum (mass*velocity) and m1*v1=m2*v2. So if a cone of mass m1 moves (impulse) at velocity v1 against an infinitely rigid cabinet of mass m2, that cabinet will move at v2. If the mass m2 of the cabinet is increased by 2, then its reaction to the same cone movement is reduced by 1/2...
Heavy as in the moving mass. And this will be a woofer. The elegant way to deal with this is active reaction force cancelation, ie push-push driver mounting.
Adding weight could be counterproductive in that more mass without added stiffness coulod move panelresonances to where they can be excited.
dave