Improving the sound in my 4x12

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Structo
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Re: Improving the sound in my 4x12

Post by Structo »

selloutrr wrote:if the cab is air tight the foam/insulaton is not nec. your speakers are already starved for box volume. cock the seams and brace the back you should be better then good.
I thought by adding the stuffing that it actually increases acoustic volume of the enclosure.
Like it tricks the speaker into thinking it's in a bigger box?

At least that was what I have read before.
Tom

Don't let that smoke out!
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M Fowler
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Re: Improving the sound in my 4x12

Post by M Fowler »

I stopped adding insulation years ago and only make sure my cabs are sealed now. I would not think it is needed.
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Aurora
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Re: Improving the sound in my 4x12

Post by Aurora »

Structo wrote: I thought by adding the stuffing that it actually increases acoustic volume of the enclosure.
Like it tricks the speaker into thinking it's in a bigger box?

At least that was what I have read before.
This is both true and false......
At mid and higher freq. the stuffing helps somewhat to control internal reflections, as it slows down the air speed trough the stuffing. At the lower octave/s, stuffing appears virtually non existent, read: little or no effect....
Air leaks in a cab designed as a closed cab, can have serious effects in the lower region.
There's a lot of myths floating around, particularly related to guitar cabs.
HiFi and PA cabs are nowadays designed to a modern regime of parameters, known as Thiele/Small - or T/S parameters, which gives a fairly accurate prediction of a result. Most of the classical guitar cabs seems more or less to ignore this regime. Another example is open back cabs, or cabs ala Dumble, with the oval hole. Recalculating these cabs using T/S parameters and modern bass reflex models gives rather hilarious results. Modern loudspeaker theory indicates these must be treated at open baffle speakers, for which there are accurate mathematical models, albeit complicated ones.
This does not mean that some of these cabs deliver excellent results for their purpose, rather than their design is a result of a combination of luck, "cut and try" methods and practical knowledge of what works and not, for these kind of cabs.
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Structo
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Location: Oregon

Re: Improving the sound in my 4x12

Post by Structo »

Yes, besides the EV 806 I want to try the Dumble oval port on my existing 2 x 12.

I have two EVM 12L's in that but somebody told me the dimensions on it were not ideal for a 212, like it was too small or something.

Ya know, the internet is a great piece of technology but it sure can spread disinformation or myths much faster then we used to with word of mouth or in print. :lol:
Tom

Don't let that smoke out!
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