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Can anyone provide me a link or book how to make a woofer at home?

Prohor

Sep 27, 2016
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I am searching from last 2 weeks on google on "How to make woofer / speaker" at home.

I have found an assembly video on youtube :
But it does not contain proper technical information such as;

If I want to make / assemble / reassemble 100 watt 8 or 10 inch 8Ω woofer at home,

1. What the permanent Magnet Size would be?
2. What kind of voice coil I should select?
3. What kind of cone I should select?
4.how I can measure 1-3 equipment to make sure that I have selected or received right quality?
5. I have old 8 inch speaker of 4 ohms, can I upgrade it to 8Ω 100 watt? ( changing old parts with improved parts)

Please help me on this topics.
 

Alec_t

Jul 7, 2015
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Welcome to EP.
I'm not aware that it's possible to buy a magnet of the right shape/polarisation, a voice coil and a cone separately, if that's your intention. I'd be interested to know the source if you have one.
I doubt you'd be able to upgrade an existing 4 Ohm speaker to a 100W one, unless the coil gap can accommodate a high current winding and the coil can be adequately cooled.
 

Prohor

Sep 27, 2016
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Welcome to EP.
I'm not aware that it's possible to buy a magnet of the right shape/polarisation, a voice coil and a cone separately, if that's your intention. I'd be interested to know the source if you have one.
I doubt you'd be able to upgrade an existing 4 Ohm speaker to a 100W one, unless the coil gap can accommodate a high current winding and the coil can be adequately cooled.

I think so, that's why I wanted to learn more and searching online. About the source: I got some info from local market that they makes speaker at various quality and prices. They showed me sample, no rating was on that! Paper made box has rating but when I connected multimeter in Ohm range, found box saying it was 8Ω but I found 3.8Ω in my meter. Now I know I brought some low quality speaker what has no rating to identify!:(

In case of famous brand speaker, I have now doubt about local supplier that they can make a duplicate low quality speakers and supply as I do not know much about them and how to identify the original one.

At the end : Thank you a lot for your information, it would help me.
 

Audioguru

Sep 24, 2016
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A high quality speaker in an enclosure designed for its specs sounds good and lasts for a long time. A cheap speaker sounds bad and fails soon.
 

duke37

Jan 9, 2011
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A speaker is defined by its impedance which varies with the enclosure. The resisance as measured by an ordinary meter will be lower than this. Ideally it will be very low to get low dissipation and high power handling.
 

Audioguru

Sep 24, 2016
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A speaker is defined by its impedance which varies with the enclosure. The resisance as measured by an ordinary meter will be lower than this. Ideally it will be very low to get low dissipation and high power handling.
No. The impedance does not vary with the enclosure. The resistance is not made very low for high power handling ability.
The impedance is high at the resonant frequency and increases at higher frequencies because it is inductive.
The resistance is only a little less than its impedance because it takes a lot of wire in its coil.

I have a 900W 18" subwoofer. Its impedance is 8 ohms and its resistance is about 6 ohms.
 

duke37

Jan 9, 2011
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The quoted impedance will always be higher than the resistance. Speakers are not ideal and the resistance can be substantial as you have shown.
The resonant frequency and Q depends on the suspension which will depend on the cabinet.
It would be interesting to see the measured impedance of the big speaker at different frequencies and show where it coincides with 8Ω. Try the driver in free air and then in a closed box.
 

hevans1944

Hop - AC8NS
Jun 21, 2012
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You old timers are about to open a doorway into an abyss of information and misinformation regarding loudspeakers and loudspeaker enclosures. Everything that can be said, and needs to be said, has already been said at least fifty years (or more) ago. OTOH, putting together my very own DIY speaker has never crossed my possibilities threshold. Unless the basket, voice coil, spider, cone, electrical terminals, braided flexible wire, rubber mounting thingy, and glue are all readily available at nearly no cost... why bother? And if such things are available nearly free, why not spend a few cents more and let third-world labor assemble it for you? Assuming they know what they are doing of course.

Audiophiles have been arguing since the 1950s as to which speaker manufacturer makes the "best" loudspeakers and what kind of enclosure to put it in. Are we ready to go down that road yet again, this time with the added uncertainties of a do-it-yourself speaker construction? Well, yes, probably. This is of course a hobby forum site, after all is said and done. Just be prepared for some epic length threads and a lot of acrimony among the participants. I think I will sit this one out.

@Prohor the first three questions you asked are good ones, but they also reveal that you are in no way prepared to design and build your own loudspeakers. Magnets: bigger is better. Voice coil: short, stiff, low mass, high current capacity. Cone: stiff, low mass, non-resonant, with ultra-compliant outer edge and spider. Good luck finding all that. This is for bass to mid-range (100 to 500 Hz tops). To produce the full range of audio frequencies requires multiple speakers, and often different technology than a "simple" voice coil driving a cone. But you did say you wanted a bass speaker, so press to MECO.

If you really want to learn how to design your own loudspeaker, and proceed to actually building it, you need to learn how they work: the physics of loudspeakers and how they interact with the environment surrounding them. A good place to start is this article in PDF form that you can download from the Internet and read. It uses some college-level math, but overall is a good preview of the things you need to consider. It provides zero design information, but it sets you a path for further understanding.

So, let's get this thread rolling...
 

duke37

Jan 9, 2011
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I have an article by Peter Baxandall detailing how to measure speaker parameters such as cone mass and compliance. The speaker he evaluates comes out with an efficiency of 1.2%. *

* Low cost hgh-quality loudspeaker. ....... Determining the electro-mechanical constants of the drive units.
High fidelity designs. A Wireless World publication. 1974
 
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