Building Speaker Enclosures
 

Do any of you guys build your own speakers? I am considering building a set for the house. How do you figure out how big to make the box?

Years ago I had a couple of roomates. One of them was in a band and the other was a master carpenter. The guy in the band was upgrading his base speakers so I got a very nice 12" bass speakers for free. Found a descent set of mids and tweeters and put it all together with all the giblets needed to make them work together.

The other roommate and I got together and built a very nice set of bass reflex speakers. The were over 2 feet wide and almost 5 feet tall. Each weighed over 100 pounds each as they were made out of "donated" pieces of door panels. I found some books on building your own speakers and tailor-made them for the sound I wanted. Bet that there are a lot of souces these days on the internet.

The sound was excellent and I used them for many years. Between the hassle of having to moving them and my falling in love with Bang & Olufsen systems made them obsolete to my needs and after around 10 years they were sold. Bet that someone is still using them today as they were built to last 100 years...

Joe

I built a set or two a hundred years or so ago. :)
Repaired a few, too.
.
Here's a good start, maybe...

Do It Yourself (DIY) Loudspeakers

http://www.audioholics.com/techtips/setup/loudspeakers/DIYspeakers.php

Re: Building Speaker Enclosures
 

Yep:
http://forums.pelicanparts.com/showthread.php?postid=1175258#post1173642

http://forums.pelicanparts.com/off-topic-discussions/149095-what-some-your-other-hobbies-post1175200.html#post1175200

http://forums.pelicanparts.com/showthread.php?threadid=149095#post1172199

Lots of math. :D

Seriously, it depends on many factors. For a good start, I would pick up a book called "The Loudspeaker Design Cookbook" by Vance Dickason. You might check out speakerbuilding.com, diyaudio.com, etc. as well. Also, see if you can find "Audio Xpress" magazine (used to be Speaker Builder magazine). Good luck, and post pics if you decide to build a set!

SmileWavy

Another vote for the Loudspeaker Design Cookbook. It's not hard, but it can get as complicated as you make it to be. Once you begin to understand and start such a hobby, like anything, you can end up in the never ending quest of finding the perfect driver, enclosure, and sound. You need at least the three basic Theil-Small parameters of a driver - Fs, Vas, and Qts - to calculate the optimal enclosure volume. There are sealed, ported, and bandpass enclosures and each has its own sound characteristics and tradeoffs. And that would only be the beginning, as you'll also be searching for the ideal midrange/tweeter combination and crossover design.

To simplify things, I'd start by working with the best drivers and designs first. You may also wish to consider preengineered designs from a place such as zalytron. Google Joe D'Appolito and the MTM arrangement. Twenty years ago, some friends and I listened to a new J D'Appolito MTM design called the Aria 5 using 2 Focal Kevlar inverted dome tweeters and four Focal 5" midbass drivers. Combined with some separately powered Vieta subwoofers, we were absolutely blown away. I still remember that day. The music was so clear, 3 dimensional, I felt like a scrub that had just had his first bite of prime USDA ribeye after having eaten rump roast his whole life. :D It also pioneered a new design in the speaker industry that still continues to this day.

I have always wanted a set of home speakers like the JBL that has dual woofers. How do you set that up would both be "active" or is one active and the other passive?

Not sure about what JBL setup you're talking about, but by dual woofers, I'm assuming you mean two drivers, one placed vertically over the other, with a tweeter in between. That is called the MTM arrangement (midrange - tweeter - midrange). In that arrangement, both midrange/woofers are active and crossover design is critical to it sounding correct. THX theatre systems are mostly by JBL and are like this.

There is also a type of design with a active woofer, and passive radiator, but such a design is more complicated and requires you to tune the mass of the passive driver to the ideal resonant frequency of the woofer/cabinet design that will provide you a flat frequency response. The Loudspeaker Design Cookbook will give you more detail about calculating such a design.

Steve W, what do you think about the single driver horn designs? I was looking at those recently, just seemed interesting.

So the MTM design is what I am looking for. I am going to keep digging until I either build them or just buy a set ready to go. I'd really rather build them myself. It sounds like I have quite a bit to learn before I do anything.
Thanks to everyone that responded.

Horns are great for large spaces such as theatres and auditoriums because of their great efficiency and high db potential, but for a home system it is largely overkill and a brute force approach to something that can be acomplished with more finesse and delicacy. Horns can induce their own coloration, and most do not have a smooth and extended overall frequency response. Horns have a controlled dispersion that will limit the soundstage and imaging in a small space. I have an old school set of JBL 4691B Cabarets (the standard pro sound reinforcement speaker back in the day) and while it can go loud and clear, it lacks low volume detail and the high end rolls off rapidly after 12 khz. Augmenting it with a separate dome tweeter helps, but it's nowhere near the clarity of the MTM systems I mentioned.

I'd recommend building one of the sets predesigned such as on the Zalytron site. The sound produced will equal premanufactured speakers costing 10 times what you will spend. You have to consider that most speaker manufacturers design for a system that sounds as good as it can using a spec drivers of the least expense to manufacture, simple crossover network, and cabinet for it to make a profit at the retail level. By using professional quality drivers, in properly designed cabinets, you end up with a system that is studio and audiophile quality. Look for example at the $50,000 and $80,000 Wilson Audio speakers (what Disney, Lusasfilm, and Sony use in their studios) and you will notice that they use the same Focal drivers in a MTM design that you can build in a kit starting at $1000 a pair.

Steve (or anyone),
I have some old stereo cabinets with assorted blown speakers. One set has a torn tweeter cone and the foam edge to the 12"passive radiators have rotted out, the other set are small advent towers with two 4" and one tweeter that someone gave me that I have yet to test to see what is wrong. Is there any way to match speakers to an old box?

If you have little or no experience at building speakers, I would agree that the Louspeaker Design Cookbook is a good start, as is "Designing, Building and Testing Your Own Speaker System with Projects", by David Weems.

For (good!) free design software, and access to a speaker design forum, drop in at:

http://www.speakerworkshop.com/

Another excellent site is at:

http://www.diysubwoofers.org

Contrary to its name the focus is not only on subwoofers, and you'll find a lot of absolute gurus contributing to the discussion forum.

Scottmandue,

Trying to re-use old enclosures is not a good idea at all, as the enclosure is designed around the unique physical characteristics of a given set of loudspeakers.