how to design speaker enclosures.

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frances-rhodes
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how to design speaker enclosures.

#1 Post by frances-rhodes »

Hello all
I just bought the complete collection of cabinet plans and I wanted to ask if anyone could point me to some books or web pages about designing speaker enclosure.
I would really be interested in learning more about that while I start building one of BFM's designs.
The PA speakers I built before were really basic, simple vented boxes of said volume, but I would like to know how, from the Thiele & Small parameters (which I learned about some years ago in physics class), to determine this volume myself for said speaker for closed or vented enclosures, and to calculate the size of vents when using them.
I have a masters degree in acoustics but we did not study speakers and enclosures in class, it was more about all the maths and physics of sound waves and how they travel through matter.

Thanks in advance.
François

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Seth
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Re: how to design speaker enclosures.

#2 Post by Seth »

Hey Francois, your best bet is/are books
Screenshot (305).png
I'm sorry, I don't have a specific recommendation. Maybe one of the other guys will.
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Bill Fitzmaurice
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Re: how to design speaker enclosures.

#3 Post by Bill Fitzmaurice »

frances-rhodes wrote: Fri Dec 08, 2023 12:37 pm it was more about all the maths and physics of sound waves and how they travel through matter.
Strictly speaking sound waves do not travel through matter. They cause matter to vibrate. When passing through air it's the molecules of air that vibrate. When they hit a solid object, like a wall, what's heard on the other side of the wall isn't sound passing through it. The wall vibrates, which then causes the air molecules on the other side to vibrate. This is why high frequencies are attenuated when you're on the other side of the wall. They lack sufficient energy to cause the wall to vibrate, so the wall won't pass high frequency vibrations on to the air molecules on the other side. Bass has plenty of energy to vibrate walls, because power density doubles with each octave decrease in frequency.

This isn't exactly current, for that matter it predates Thiele/Small. But it remains a definitive work, which you'll find in every acoustic engineer's collection: http://cyrille.pinton.free.fr/electroac ... /Olson.pdf

frances-rhodes
Posts: 10
Joined: Thu Sep 01, 2022 9:51 am

Re: how to design speaker enclosures.

#4 Post by frances-rhodes »

Seth wrote: Fri Dec 08, 2023 4:44 pm Hey Francois, your best bet is/are books
Screenshot (305).png
I'm sorry, I don't have a specific recommendation. Maybe one of the other guys will.
Thanks a lot, I'll see if I can find any of these books here!
Bill Fitzmaurice wrote: Fri Dec 08, 2023 5:43 pm
frances-rhodes wrote: Fri Dec 08, 2023 12:37 pm it was more about all the maths and physics of sound waves and how they travel through matter.
Strictly speaking sound waves do not travel through matter. They cause matter to vibrate. When passing through air it's the molecules of air that vibrate. When they hit a solid object, like a wall, what's heard on the other side of the wall isn't sound passing through it. The wall vibrates, which then causes the air molecules on the other side to vibrate. This is why high frequencies are attenuated when you're on the other side of the wall. They lack sufficient energy to cause the wall to vibrate, so the wall won't pass high frequency vibrations on to the air molecules on the other side. Bass has plenty of energy to vibrate walls, because power density doubles with each octave decrease in frequency.

This isn't exactly current, for that matter it predates Thiele/Small. But it remains a definitive work, which you'll find in every acoustic engineer's collection: http://cyrille.pinton.free.fr/electroac ... /Olson.pdf
I was taking a shortcut to sum up a bit faster what I studied (and also because it's a lot harder for me to explain in a foreign language, specially 15 years after I got out of college), but yes, it's not a "travel" as a speaker or any sound source don't emit particles like a light bulb does, it's a transmission of energy from one atom to the next ones until there is no energy left to transmit.
Thanks a lot for the link! I will try to find a copy of this book

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Bill Fitzmaurice
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Re: how to design speaker enclosures.

#5 Post by Bill Fitzmaurice »

You don't need a copy of the book, just download it.

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