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Sealed / Enclosed Box Plans for 18" or Greater

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Category: Plans
Forum Name: Other plans
Forum Description: Discussion / Questions about all the other plans
Printed Date: 30 September 2020 at 10:56am
Software Version: Web Wiz Forums 12.03 -

Topic: Sealed / Enclosed Box Plans for 18" or Greater
Posted By: darkmatter111
Subject: Sealed / Enclosed Box Plans for 18" or Greater
Date Posted: 21 October 2019 at 11:59am

New to this forum, and have been searching the site to see how many here have produced sealed box designs?

I am interested to see if anyone has produced any sealed box (enclosed) designs for drivers in the 18 or 21" range.

The real question is (in practical terms i.e that have been used) how many units in the 18" plus range are suitable for this kind of loading?

The basic rule of thumb some use is to look at the Efficiency Bandwidth Product of the driver, where EBP = fs/Qes.

A high (>100) EBP mandates use in a vented box and a low EBP (<50) implies the use of a sealed box.

These are not hard and fast rules, but act as an indicitive guide.

One driver I have seen used elsewhere is the Precision Devices PD186/2 which has an EBP of ~ 62

I am sure there are plenty of others.

I would welcome any suggestions for suitable drivers that members have found to work well in practice.

One could hunt for suitable units based on the rules above, but experience in the field always trumps theory in my book.

My preference is for an overall low system box Qtc of 0.707 butterworth or lower even towards a Bessel alignment.

Boxes of 200 litres or greater pose no problems to accomodate!!

The use here is domestic audio in a large room.


Posted By: darkmatter111
Date Posted: 24 October 2019 at 12:24pm
I am looking carefully at several bass drivers for this three way sealed bass project

Precision Devices PD186/2 which has an EBP of ~ 62 -

This one is very highly thought of with an EBP of 69 massive x-max and plays well up to and above 250 Hz
BMS 18N862 -

I have four of these classics but they need new surrounds as they have the dreaded foam rot
JBL 2245H -

I have been looking at these which have a well established reputation and  are used in the wellrespected Quested Monitors -

One outsider is this one with a nice big roll surround and EBP of 51 -

I have not ruled out smaller 15" drivers
This one is very good with an EBP of 57 - -



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