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Equations and all that

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speaker monkey View Drop Down
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    Posted: 22 August 2008 at 3:04pm
   I was just wandering if anyone had or knew how to get the underlying equations for things like hornresp etc. and the science behind it? Some books perhaps?
Sorry if this is a repeated question, tried the search and didnt really find what I was looking for. Im after texts and books rather than excel spreadsheets or software, if poss.

monkey x
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Deadbeat View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Deadbeat Quote  Post ReplyReply Direct Link To This Post Posted: 22 August 2008 at 3:35pm
It's good to hear that someone wants to learn the math. It helps you understand what is going on.

however we all use simulations because we (should) know the math behind and know what it's doing - the simulation is like a graphing calculator on steroids. So that's taken care of, I hope you weren't thinking of doing it that way. We've had people think of doing that...

Hornresp's results are consistent with math by a professor called William Marshall Leach. Hornresp also takes in a plethora of other math, which is what we will focus on later.

This is his website:
http://users.ece.gatech.edu/~mleach/

This is the part that we are interested in:
http://users.ece.gatech.edu/~mleach/audiothings.html

This is the part we are REALLY interested in, his AES paper.

http://users.ece.gatech.edu/~mleach/papers/HornPaper/HornPaper.pdf

Now, leach's math is actually based on a modified model that appears in Harry Olson's 'Acoustical Engineering', a standard manual which you should buy. No jokes.

Leach's simple model allows you to design a horn based on a driver's t/s parameters and wanted frequency range, or do the opposite starting off with the horn and finishing with a set of t/s parameters. Bear in mind that this is a very simple model - it doesn't take in folds or standing waves or reflections anywhere in the horn. The main assumption is that all of his math takes place in an infinitely long exponential horn. This means that you're not gong to really get the results from the math when measuring a compact horn. Leach also makes a few other assumptions detailed in his paper. The math should serve as a starting guideline for your designs.

Now you consider all the other math for predicting output, distortion, and other things.
This is detailed in a lot of other papers. While I don't know all of this offhand, I'll edit this post when I find them in my links bucket.

EDIT:

these are AES article ref numbers, make a trip to your local AES library.

"Design Factors in Horn-Type Speakers",
D.J. Plach,
JAES, Vol. 1, pp. 276-281, 1953 October.

"The Function and Design of Horns For Loudspeakers",
C.R. Hanna and J. Slepian,
JAES, Sep 1977, Vol. 25, No. 9, pp. 573-585.
(Reprint of 1924 article)

"Discussion: The Function and Design of Horns For Loudspeakers", (OPTIONAL)
JAES, Mar 1978, Vol. 26, No. 3, pp. 131-138.
(Reprint of 1924 article)
"A New Family of Horns"
Vincent Salmon, 7 pp.
JASA, Vol. 17 No.3 January 1946
This introduces the brand new (well, then) hyperbolic exponential horn used in most modern bass horns.

Dinsdale horn articles
http://www.volvotreter.de/dl-section.htm

Scroll to the bottom for the Dinsdale articles. remember to read the disclaimer from Dr. Edgar


Edited by Deadbeat - 22 August 2008 at 4:02pm
Away on extended leave.
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Jake_Fielder View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jake_Fielder Quote  Post ReplyReply Direct Link To This Post Posted: 22 August 2008 at 3:38pm
http://www.xlrtechs.com/dbkeele.com/papers.htm
 
Maybe this would be interesting, I recomend no.4 on the list.
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Deadbeat View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Deadbeat Quote  Post ReplyReply Direct Link To This Post Posted: 22 August 2008 at 3:42pm
Thanks Jake. The ones in my link bucket from him would be (+ that one):

The one at the very very top (what's so sacred about exponential horns?)
http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20(1975-05%20AES%20Preprint)%20-%20Whats%20So%20Sacred%20Exp%20Horns.pdf

11.
http://www.xlrtechs.com/dbkeele.com/PDF/Keele%20(1977-05%20AES%20Preprint)%20-%20LF%20Horn%20Design%20Using%20TS%20Paras.pdf

I hate wading through AES links.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Jake_Fielder Quote  Post ReplyReply Direct Link To This Post Posted: 22 August 2008 at 3:45pm
Yeah, they're actually the only three that i have properly read, (as in working on examples and stuff as well). It was some time ago tho....
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Deadbeat Quote  Post ReplyReply Direct Link To This Post Posted: 22 August 2008 at 4:11pm
In terms of books, I recommend for starters:

Harry Olson's 'Elements of Acoustical Engineering'
http://www.amazon.co.uk/Elements-Acoustical-Engineering-Harry-Olson/dp/B001B0NCQC/ref=sr_1_5?ie=UTF8&s=books&qid=1219417528&sr=1-5

Leo Beranek's 'Acoustics'
http://www.amazon.co.uk/Acoustics-Leo-L-Beranek/dp/088318494X/ref=sr_1_5?ie=UTF8&s=books&qid=1219417420&sr=8-5

Bit expensive, but worth it. they're the standard texts. Then we can get onto modern advancements (which presume knowledge of these already).

Oh, and JW Rayleigh's 'theory of sound', I don't have a link.
Originally published in the 19th century, but still going strong.
Gives you a very strong foundation.

Here's quite a cheap source of these, though. Not sure whether they ship to the UK.
http://www.audioxpress.com/bksprods/BKSACOACO.htm
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speaker monkey View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote speaker monkey Quote  Post ReplyReply Direct Link To This Post Posted: 23 August 2008 at 5:15pm
Hey, thanks guys.
cheers for all the positive stuff. Lots of reading for me to do then, good stuff.
speak to you in a few months Wink

monkey x

PS anymore links/books are welcome

PPS AES library? from what I can gather you pay (albeit not a lot) for the PDF texts online..?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Deadbeat Quote  Post ReplyReply Direct Link To This Post Posted: 23 August 2008 at 5:25pm
Hi,

Some of the authors actually give away their texts for free, like Don Keele.

However, a lot are hidden in the AES, where you have to pay a fee.

I assume you live in the UK, so AES representation isn't a problem.  Ring your local section and they'll tell you where to find texts (there's a few dedicated libraries if I'm not mistaken), or it should be on the website. Otherwise there's a high possibility of certain university libraries having such texts in anthology/preprint format. I think (link I posted)Old Colony Sound Lab's AES anthology prices are a steal though. If you are really into it, you could become a member.

What other reading you do depends on what you want to learn. General Acoustics? Psychoacoustics? Design of HF horns? There's books and papers for pretty much everything.
Away on extended leave.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote tb_mike Quote  Post ReplyReply Direct Link To This Post Posted: 30 August 2008 at 7:48am
Yeh I find them in the uni library.They had an old copy of olsons book too.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote _djk_ Quote  Post ReplyReply Direct Link To This Post Posted: 03 September 2008 at 7:32am
    Posted by djk (M ) on January 28, 2004 at 00:50:52

From Olson: Acoustical Engineering

Fig.5.10 (100hz horn with different mouth sizes)

http://forums.klipsch.com/idealbb/files/Olson 1.gif

Fig. 5.11 (100hz horn with different throat sizes)

http://forums.klipsch.com/idealbb/files/Olson 2.gif

djk
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Post Options Post Options   Thanks (0) Thanks(0)   Quote snowflake Quote  Post ReplyReply Direct Link To This Post Posted: 14 May 2020 at 5:45pm
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Edited by snowflake - 15 May 2020 at 5:09pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote snowflake Quote  Post ReplyReply Direct Link To This Post Posted: 15 May 2020 at 4:22pm
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Edited by snowflake - 15 May 2020 at 5:10pm
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