If you're thinking of it in mechanical terms, and only considering displacement, then yes, it is a bit perplexing.
What happens when we compress a gas is, it raises the temperature of the gas. The smaller* the cabinet volume to cone displacement ratio, the more the temperature will rise. The one thing about preferred stuffing materials is, the better ones are also preferred for heat insulation. By filling the box with insulation, we make the box "bigger" by capturing the heat generated by the aforementioned compression and reducing the change in temperature, thus simulating a larger box.
Dave alluded to this earlier when he mentioned "adiabatic" and "isothermal".
* by "smaller", I mean closer to 1.
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so as the air in the box warms up it tunes the box lower because...... ?
it must change the speed of sound, which must effect the lengths of the waves somehow... ?
how does compressing gas raise its temprature?
that would mean some speakers have to "warm up" to start sounding right. however for a vented cabinet this wouldnt really apply because the box is cooled by the vent
so if you got a speaker box and fitted a radiator inside it would it make the box even larger? obviously you could have to have a cooler set on the driver somehow.
so like a fridge the back gets hot so the inside is cool. so u can cool the woofer with a internat cooling thing, and warm the box up to 300degrees or something" material perrmitting.." then u could have a tiny box. lot of effort for a tiny box though
so like a fridge the back gets hot so the inside is cool. so u can cool the woofer with a internat cooling thing, and warm the box up to 300degrees or something" material perrmitting.." then u could have a tiny box. lot of effort for a tiny box though
Heat makes the box smaller accoustically speaking. With a lot of fibers in the box e large surface means that the air and the fibers exchange heat. So the fibers work as a heat sink evening out the temperature changes. Hot air really does not carry that much heat as the density is only about 1.3 g/liter at STP. ( In imperial units it should be about one once per cubic feet). Diesel engines heat up the air fuel mixture by compression so it ignites by itself.
The problem is that the mass or the port should "bounce" on the air spring of the enclosure.Adding a lot of resistance reduces the output of the port and you end up wih a leaky closed box and the whole point of a ported box is usually to get increased radiation resistance from the the port to aid bass output or to reduce cone motion for a given output.
The problem is that the mass or the port should "bounce" on the air spring of the enclosure.Adding a lot of resistance reduces the output of the port and you end up wih a leaky closed box and the whole point of a ported box is usually to get increased radiation resistance from the the port to aid bass output or to reduce cone motion for a given output.
My understanding was always that in creating flow resistance you damp the air spring thus lowering Qtc, not actually lowering Fb but giving only the lowered Q of a larger box, not the lowered F.
I wonder what would be the maximal volume enlarging possible in theory.
What materials would be optimal?
Also: As the heating and cooling happens in sync with the pressure changes of the sound I assume it has a low pass filter effect and does not work with higher frequencies?