From: Bob Blick <bobblick@outlook.com>
To: Microcontroller discussion list - Public. <piclist@mit.edu>
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Date: Thu, 19 Mar 2020 15:44:20 -0700
Subject: Re: [OT]: Optimal speaker enclosures.
Thread-Topic: [OT]: Optimal speaker enclosures.
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Hi Justin,

I'm not an expert on loudspeakers, but I do have some experience with diffe=
rent kinds of cabinets. You are describing an infinite baffle cabinet. Anot=
her type of cabinet that has total isolation from front to rear is a sealed=
 cabinet, also called acoustic suspension.

There are lots of different types of cabinets. Another popular type is a ba=
ss-reflex cabinet, which is ported.

Depending on your speaker's characteristics, it will work better or worse i=
n different types of cabinets. The three most important parameters are fs(r=
esonant frequency), Qts(the "Q" of the speaker), and Vas(a measure of compl=
iance). Generally speaking, infinite baffle enclosures need a low-Qts speak=
er.

Those three parameters are part of what are generally referred to as Thiele=
-Small parameters. Thiele says that if you are making a ported cabinet, and=
 your speaker has a Qts of .38, you would make the volume of the cabinet th=
e same as Vas, and tune the port to fs. If your speaker has a higher Qts yo=
u make the enclosure bigger, if Qts is smaller, make the cabinet smaller. T=
hankfully there is software for figuring this out.

BTW, another popular thing people are doing in vehicles these days is calle=
d "aperiodic membrane". It does require a low to medium Qts speaker and mor=
e power, but it delivers good fidelity.

Cheerful regards, Bob

________________________________________
From: piclist-bounces@mit.edu <piclist-bounces@mit.edu> on behalf of Justin=
 Richards <justin.richards@gmail.com>
Sent: Thursday, March 19, 2020 2:52 PM
To: Microcontroller discussion list - Public.
Subject: [OT]: Optimal speaker enclosures.

Noticing there is a resident expert I have a question I have often pondered=
-

Would the optimum theoretical enclosure be a speaker mounted in a wall with
infinite dimension such that the front of the speaker can not see the rear.

1. Optimum as in fidelity and not efficiency.
2. "See" as in the sound from the front can not travel to the rear.
3. A wall of infinite dimension looking like an infinit xy plane .

I have concluded that an infinte xy plane would be optimal after installing
speakers in the rear wall of a ute with little care or funding at the time
and discover I was blown away by the performance.

Since that time I have tried installs in sedans with more money and care
and always disappointed.

Cheers Justin
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