posted
!!! ON SEALED BOX ONLY !!! I recently tried to add some mass on a woofer cone to decrease the Vas and consequently get lower resonant peak frequency of a box. Originally, the woofer is a single cheap 10inch with Vas of 2,8 cu ft put on a box of 0,7 cu ft net. The fb was 65Hz before adding mass on the cone, and decreased to 43Hz after adding 100g om it.
My idea is to reduce the need vol of a woofer to play lower freq. The first test was good and when i tried to simulate it on BassBox Pro soft, the result was the same!
Now i wonder if the needed volume of all woofers depend only of the mms parameter??
Can i conclude that it's possible to tune a system just by changing the mass of the woofer (sealed box only)
What do ou think about that?
------------------ Show me the bass !
Posts: 643 | From: Quebec city | Registered: Mar 2000
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posted
Mas loading the cone should not change the Vas component of the driver. I may be mistaken here and will look into it.
What you should be changing is the Qms (and resultantly the Qts) and the Fs.
By mass loading you force the woofer to resonate at a lower frequency regardless of the box design. Good if you only want the low end but it can (will) mess up you driver control. Of course, stuffing it into that way small box restores some control too.
I am glad your experiment turned out satisfactory to you but would not try to make any conclusions or assumptions from it.
------------------ Blow your mind - PORT your box!
posted
You would change any parameter that deals with mass of the cone, obviously. The resonance frequency will thus be altered, yes, along with a slew of things.. But bear in mind!
You're increasing the mass of the cone but you AREN"T increasing the force factor of the magnet.. Therefore, you end up with a sub that is completely out of whack and you have to control it using other methods.
In achieving the lower Fs and dropping the box volume, you're retaining approximately the same low frequency extension but you will lose some.. I don't know if the tradeoff is worth it.
But.. It gives you one more variable to manipulate. Make sure you bear physical stress on the load bearing cone parts in mind when/where adding mass
ShadowStar
------------------ Still looking for that CHEAP Thunderdome :D
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Posts: 2578 | From: Somewhere In the Northeast | Registered: May 1999
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