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richa561
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DIY speaker design and construction

hey all, my name is Luke Richard and i am young eager audiophile enthusiast. Over the past couple years i have been soaking up as much info from the net and various sources as possible regarding audio electronics and loudspeaker design and technology. Recently i have embarked on my own loudspeaker design and construction project using MK drivers from an old pair of S-85 bookshelf speakers. I am just posting to get a discussion going on various recommendations, opinions and advice regarding loudspeaker design and construction, please feel free to post whatever you deem helpful and/or interesting. Hopefully this post generates some discussion on the topic of DIY loudspeakers and i look forward to your input, thanks, Luke

Jan Vigne
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Re: DIY speaker design and construction
Colnmary
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Re: DIY speaker design and construction

Hi Luke,

Its been a few years since I was young, but I am still enthusiastic about DIY speaker buiding.

I bought and modified my first pair of Loudspeakers in 1973 at the age of 17. They were a very large Infinate Baffle, with 12 inch Richard Allen full way drivers. I added a 6 inch paper mid range and a 1 inch plastic dome tweeter. I designed a 3 way, 12 octive/dBL crossover, based on Butterworth tables. Did all the cabinet work and cross over work myself. The finish looked a little had made, but it sure sounded sweet and went LOUD! I used a Quad 405 Power amp to drive them.

Like many, I still dream of making my perect speakers. I prefer the bass of a sealed box design. I have found with better tweeters and faster midrange drivers, many speakers with ports are still a little slow in the bass. I still think the Infinate baffle, (Closed box) design though trades a little in effiency, it seems to have tighter, more detailed, start and stop on a dime bass.

Anyway, welcome to the amazing varied world of speaker design, the site that was posted above this post has an amazing forum on speaker design.

absolutepitch
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Re: DIY speaker design and construction

There are many ways to get into DIY speakers. I guess it depends on how detailed you want to be at any given time.

I too made my own enclosures to fit the drivers I chose. the enclosures were braced for more stiffness and damped with fiberglass. I started with a single, full-range driver, which really didn't speak the full-range, but was asked to do so.

Then I added a tweeter in a second enclosure and mechanically isolated from the first. Later I added a midrange.

All the while I tried various crossover configurations (series or parallel) and parts. I chose a first-order network for phase reasons and chose drivers that could cover the various frequency bands accounting for the driver size and sound dispersion angle so it would be as hemisherical a radiation pattern as possible. I wound the inductors by hand (tough) on machined plastic bobbins. I then treated the baffle board for diffraction effects with absorbant material.

So you can get started simple and get more complicated as you see fit. My purpose for DIY is that it was cheaper for a college student that couldn't afford the good stuff.

Well, I later bought some of that good stuff and compared to my DIY speakers. No question about it - the pros get it done better, although what I built served its purpose, and am still using it as a secondary system.

BrianP
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Re: DIY speaker design and construction

Hi Luke:

You have chosen a great time to jump into DIY. Many more resources are available to the hobbyist now than when I started building speakers some 20 years ago. Some very sophisticated design and measurement software is now available at reasonable prices. FRD consortium has some excellent downloadable freeware. Books such as "Loudspeakers 201" and Vance Dickason's "Loudspeaker Design Cookbook" cover the theory in comprehensive detail. A vast selection of drivers and parts are to be had from several distributors, including Madisound, Meniscus, Parts Express, and Zalytron. The Parts Express and Madisound discussion boards provide an opportunity to pick the brains of other hobbyists, including some very advanced designers and engineers. And if you just want to build something really good, without designing from the ground up, there are MANY excellent kits for sale, and many free plans posted on various designers' websites. Just for starters you might want to look at the offerings from GR research, Linkwitz Labs, MurphyBlaster productions, Selah Audio, Zaphaudio, North Creek, Music and Design, and RJB Audio, in addition to the major distributors mentioned above.

What's really great about this hobby is that you learn so much--about electronics, acoustics, and woodworking--while having hands-on fun and, not incidentally, ending up with some really good speakers to listen to, at a fraction of the cost of a comparable off-the-shelf system.

KBK
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Re: DIY speaker design and construction

Don't forget DIYAudio.com. Likely the finest resource in DIY speaker information and experts anywhere. A pretty crusty and cranky bunch at times, (maybe it's just me ), but great info is available there.

Elk
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Re: DIY speaker design and construction


Quote:
I wound the inductors by hand (tough) on machined plastic bobbins.


Color me impressed!

absolutepitch
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Re: DIY speaker design and construction

Thanks for the compliment. LukeDuke asked about DIY speaker systems. Well, I didn't want to bring this up but here goes.

After I wound four crossover coils, I wondered what it would be like to wind voice coils. So I got a bunch of magnet wire and tried. I made coils with fine wire and less fine gauge wire. Trade-off between resistance and mass and physical size to fit into the magnetic gap.

Later I was able to get enough coil to equal about 4 ohms DC. What to do with the coil? Well, of course, make a speaker cone and see if it speaks. Sure enough, the coil added to a cone does get the thing speaking using a magnet from an old damaged woofer.

Unfortunately, I did not have access to any of the flat ribbon wire often used now in voice coils; all my wire were round cross-section and therefore less efficient.

The main thing is that I learned a lot by doing it. I appreciate how much work it is to design and build a driver - materials, electromagentism, machining skills, mathematics, handiwork, structural mechanics, adhesives, thermal issues, to name a few.

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