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Thread: tower cans question
09-05-2014, 12:59 PM #1
tower cans question
I bought some tower cans to install some 6.5" speakers in. I was wondering if they would be better if I filled the can full of some sound dampener or not?2003 Moomba Outback with 283 hrs on the 310HP Indmar. Its in Cherry condition also and now we will again start to use the boat after a few years off.
09-08-2014, 12:51 PM #2
You really cannot change the laws of physics, regardless of brands. Sound behaves in a pretty consistent manner. Sound comes off both sides of a speaker cone, and in a can or other enclosure the sound from the back of the cone is easily reflected back to the speaker, with some coming back through the speaker cone. This usually causes problems from a pure frequency response standpoint...
I will usually recomend using polyfill pillow stuffing, with the can loosely filled, and I do mean loosely since tightly packing it does more harm than good. What we want to do is absorb the sound from the back of the cone inside the can so the sound cannot bounce off the interior can walls and back through the midrange.
Some would argue with me, but I am inclined to say that any mass-loading panel treatments, (Dynamat as one brand-name example) probably would only provide minimal improvement. A can, by its shape is going to be pretty non-resonant. Mass-loading sheets provide a different type of damping when compared with the polyfill. A product like Dynamat provides damping of resonances of the can material itself, (think like a bell rinigng) while polyfill provides damping directly to the speaker's soundwave as it travels inside the can.
So to kind of summarize, if you want to go over the top, and you can afford to do dynamat AND polyfill, do both. You get two different kinds of sound damping that way.
If you can only do one or the other, just get the pillow stuffing and don't mess with the Dynamat-style product. You will get way more bang for your buck. You probably would not hear a difference between a polyfill-only can and a polyfill-and-Dynamat can anyway, not in this application...
09-08-2014, 01:28 PM #3
One thing to consider with a product like a Dynamat, is reducing the volume of an already small pod. This reduces the mid-bass.
09-08-2014, 01:43 PM #4
I was thinking a poly fill also. Thanks you for the response. Might add a couple better 6.5's also. I just bought the speakers for the cans as the speakers r knockoff crap lol2003 Moomba Outback with 283 hrs on the 310HP Indmar. Its in Cherry condition also and now we will again start to use the boat after a few years off.
09-09-2014, 12:55 PM #5
The surfaces of a round pod in particular reflect back against the cone in a very coincidental manner. So you can get a profound peak at one frequency and a profound dip at another. This can add an unwanted and audible signature to the sound. Polyester fiberfill would have to be extremely dense in such a small pod displacement to completely nullify this effect. And too much polyfill density, as mentioned above, will hurt you more than it will help. Pull apart the polyfill and stuff the entire pod loosely. That's the best you can do. Keep in mind that once the speaker basket/motor/cone is inserted into the pod there isn't much air mass left over. As is, a typically automotive or in-boat coaxial placed in a small pod will begin the roll-off significantly above 200 Hz.
Dynamat won't do much to retard the interior reflections but it will damp the resonance of the pod material. A denser foam will aggressively retard the internal reflections, but again you are changing the pod displacement and raising the low frequency roll-off point.