# A beginners attempt at understanding loudspeakers



## Steak (Mar 16, 2006)

I want to understand the theory behind loudspeakers, and I got the advice to start by reading the loudspeaker design cookbook (if you want it, shoot me a pm). Im opening this thread so that you guys can help me understand and discuss the contents of this book.

Ill post whenever I read something interesting or things I dont understand.


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## Steak (Mar 16, 2006)

well chapter 0 begins explaining how speakers work. The main parts of a simple speaker are shown and how it works.. I pulled an old speaker and butchered it. Try to identify the main parts: surround, cone, dust cap, spider, voice coil, frame, pole piece, front plate, back plate, magnet, vent, gap.


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## Steak (Mar 16, 2006)

Im having troubles with chapter 0 lol

I guess this book asumes that you have some undestanding on loudspeakers, which I dont.

It asumes that I know what third order harmonic distortion is, or what Qms means. Ill have to research on this before I continue...


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## Steak (Mar 16, 2006)

HARMONIC DISTORTION

A magnetic tape recorder's harmonic-distortion specification is very important. It usually determines where the record level of a recorder's electronics should be set. The record level is also used to determine the signal-to-noise ratio and frequency-response specifications. A typical harmonic-distortion specification might read "1% third harmonic of a 100-kHz signal at 60 ips." This means that the magnetic tape recorder has 1% third-harmonic distortion of a 100-kHz signal at 60 ips.

HARMONIC-DISTORTION DEFINITION

Harmonic distortion is the production of harmonic frequencies by an electronic system when a signal is applied at the input.

When an input signal goes through nonlinear electronic circuitry, the output signal will include some harmonic distortion (or unwanted frequencies).

If you analyzed this distortion, you'd see that a pattern exists. A pattern, whereby the frequency of each unwanted frequency is a multiple (X1, X2, X3, etc.) of the center frequency of the input signal.

There are two types of harmonic distortion: even-order and odd-order.

If the frequencies of the distortion are 2, 4, 6, etc., times the center frequency, it's even-order harmonics. If the frequencies of the distortion are 3, 5, 7, etc., times the center frequency, it's odd-order harmonics.


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## Steak (Mar 16, 2006)

There is a material where the coil is wound. This is called the former. It can be conductive or non conductive (such as kapton). The non conductive formers do not induce eddy current (whatever that is!), causing Qms to be lower and thus exibiting somewhat lower distortion.
Also, since there are no eddy losses with non conductive formers, (and they tend to be lighter, hence lower mass), they tend to be more efficient in the higher midrange frequencies..


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## Oliver (Jun 25, 2007)

http://www.parts-express.com/pe/sho...esign cookbook&CFID=13029434&CFTOKEN=83565680
*EXCELLENT BOOK ^^^*
Thiele/Small - Wikipedia, the free encyclopedia

quote>
* Sd - Projected area of the driver diaphragm, in square metres.
* Mms - Mass of the diaphragm, including acoustic load, in kilograms.
* Cms - Compliance of the driver's suspension, in metres per newton (the reciprocal of its 'stiffness').
* Rms - The mechanical resistance of a driver's suspension (ie, 'lossiness') in N·s/m
* Le - Voice coil inductance measured in millihenries (mH) (Frequency dependent, usually measured at 1 kHz).
* Re - DC resistance of the voice coil, measured in ohms.
* Bl - The product of magnet field strength in the voice coil gap and the length of wire in the magnetic field, in tesla-metres (T·m).
quote>

HowStuffWorks "How Speakers Work"
quote>
Inside this Article

1. Introduction to How Speakers Work
2. Sound Basics
3. Differentiating Sound
4. Making Sound
5. Making Sound: Diaphragm
6. Making Sound: Voice Coil
7. Making Sound: Magnets

8. Driver Types
9. Chunks of the Frequency Range
10. Sealed Speaker Enclosures
11. Other Speaker Enclosures
12. Alternative Speaker Designs
13. Lots More Information
14. See all Speakers articles
quote>

HowStuffWorks Videos "Deconstructed: How Speakers Work"


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## Steak (Mar 16, 2006)

thanks for the help a*hole. Ill give those links a read after work.

I must say that I recommend this reading to everyone. I finally have a clue what a shorting ring does, how former types affect performance, how different pole piece designs affect outcome, etc.... Im loving this!


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## el_chupo_ (May 27, 2007)

Hey steak, do you have the book electronically? 

I would love to read it!!


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## Steak (Mar 16, 2006)

el_chupo_ said:


> Hey steak, do you have the book electronically?
> 
> I would love to read it!!


I do, PM sent. Please check it out, and if you like it (Im sure you will), purchase the hardcopy..


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## el_chupo_ (May 27, 2007)

Steak said:


> I do, PM sent. Please check it out, and if you like it (Im sure you will), purchase the hardcopy..


Thanks!

I was thinking of buying it anyways, and I like having stuff in book form.

Ill do some browsing and make sure!


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## socal75 (Jul 31, 2009)

Good info, Thanks!


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## eus090474 (Jul 2, 2009)

Hey steak, think you could send me the electronic copy too?


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## Steak (Mar 16, 2006)

eus090474 said:


> Hey steak, think you could send me the electronic copy too?


PM sent!


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## zx3frenzy (Feb 5, 2009)

i would love a copy also please!!!


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## Hoad (Oct 18, 2008)

Could I get a copy as well?


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## Steak (Mar 16, 2006)

Sure, pm me your email addy.


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