Speaker enclosure calculations (minimum BFM content)

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profwacko
Posts: 25
Joined: Tue Oct 30, 2007 4:53 pm
Location: Central Texas

Speaker enclosure calculations (minimum BFM content)

#1 Post by profwacko »

I am trying to make an informed decision on a replacement woofer for a Leslie 125 (single 12" full range, no upper horn).

The cabinet has a down-firing woofer into the rotating drum below and has triangle-shaped ports in 2 corners of the baffle.

This is similar in construction to the Simplexx cabinets (I have had all of the plans since 2009 and many, many updates).

Where can I get more information on how this type of port construction affects the enclosure calculations.

ADVthanksANCE

-Jack (in central Texas)
There are 10 kinds of people in this world:
Those who understand binary, and those who don't.

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Bill Fitzmaurice
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Re: Speaker enclosure calculations (minimum BFM content)

#2 Post by Bill Fitzmaurice »

You need to reverse engineer the cabinet, putting the results into a speaker modeling program like WinISD 0.7, using a number of different drivers to find the specs that work best.

profwacko
Posts: 25
Joined: Tue Oct 30, 2007 4:53 pm
Location: Central Texas

Re: Speaker enclosure calculations (minimum BFM content)

#3 Post by profwacko »

That's exactly what I am attempting to do.

My problem is figuring out how to calculate the area of the ports.

Are they simply the total area of the vents and the port length equal to the thickness of the baffle?

-Jack
There are 10 kinds of people in this world:
Those who understand binary, and those who don't.

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Bill Fitzmaurice
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Posts: 28619
Joined: Tue May 02, 2006 5:59 pm

Re: Speaker enclosure calculations (minimum BFM content)

#4 Post by Bill Fitzmaurice »

That's correct.

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