It was making my own Hi-Fi speakers and other miscellaneous stereo equipment that got me seriously into woodworking. For woodworkers and lovers of music this is a great way to combine interests. I highly recommend making one’s own speakers to anyone that wants a seriously good stereo system and is willing to put some time into learning how to go about it. It’s a very satisfying project and you can save some real money in the process at the expense of your time and effort (but it’s a lot of fun).
On this page, I have a personal account of my adventures in stereo and speaker building.
I have some photos of the speakers I built some 5 or 6 years ago and I go a little bit into the details. The information on building speakers I have is now somewhat out of date as to suppliers and advice on components, but the Internet is a great resource and one might start as I did with the rec.audio.* newsgroups. A word of caution though - choosing stereo equipment is very subjective and I eventually got tired of the nonsense and arguing over which piece of equipment is best and what’s really audible and what’s not. What I write here is my own personal experience and opinions. Also I make no claim of "golden ears". I'm seriously middle aged and my high frequency hearing ain't what it used to be, but with lots of serious listening under my belt I have a pretty clear idea of what I can hear and what I might be imagining.
Speaker system: (L to R) Subwoofer #1, Thendara satellite speakers, Subwoofer #2
In the beginning.....
I’m never in the forefront of technology. Around 1989 I finally bought a CD player and was simply blown away by the sound quality. When I bought the CD player I also bought a new set of speakers that were much better and more accurate than the cheap speakers I’d been using. My joy in listening to music increased enormously and my interest in classical music rekindled. I still like classic rock and more eclectic types of music (Andean flute music, anyone?), but classical music is my favorite.
As I sunk deeper into the depths of this wonderful hobby (?), I began to pursue the "Holy Grail" of the ultimate sound quality. But high-end audio is one of the most expensive hobbies I’d ever fallen into and I needed to find some way of compromising and controlling how much I spent. I also became very wary of the snake-oil salesmanship and pseudo-science that characterizes much of the high-end audio industry.
Through my reading and the rec.audio newsgroup, I learned an awful lot about the technology of hi-fi in general and loudspeakers in particular (although the details of the electrical engineering continue to elude me). I also became acquainted with the fringe-element enthusiasts that consider hi-fi a do-it-yourself activity. So at some point in my quest, I decided to build my own subwoofer. Getting accurate low-bass sound into a stereo system is difficult and very expensive in store-bought systems. Once you’ve heard the real thing, though, it’s difficult to do without it.
I bought a kit consisting of a 12" woofer, a passive crossover (separates the high frequencies from the lows), and some miscellaneous components from a place call Audio Concepts (http://www.audioc.com). I also bought a wonderful book called the Loudspeaker Design Cookbook by Vance Dickinson that allowed me to play around with all sorts of equations, learn more about the basics of speaker building, and come up with my own specifications for a subwoofer. I chose a design to give the flattest response and lowest frequency cutoff in a sealed (acoustic suspension) cabinet. The design variable here is the internal volume of the box which turned out to be 5 cu. ft. (more on this later).
I was just a beginning woodworker and my first subwoofer was simply built out of particle board and 2x2 lumber. Lots of screws and glue. I finished the exterior with simulated walnut grain formica. I was a little taken aback by the size of the cabinet – about the size of a small refrigerator, but words cannot describe the thrill I got when I hooked the speaker up to my stereo system and heard the rumblings and felt the air movement of deep bass.
On the domestic front all was not well though. My wife took one look at my creation, occupying a fair chunk of our family room, and announced,
"I can’t live with that thing in the room."
Was I shocked, dismayed, heartbroken, or upset by this? No, not at all. This enabled me to skillfully enable secret plan B. I told her I would instead move the subwoofer and the rest of the stereo system into our largely vacant and little used living room, but that I wanted leniency to arrange things the way I wanted them. I was able then to pretty much create a dedicated listening room. I also embarked on a scheme to upgrade my overall stereo system so that I had a really good system for music in the living room, while the backup (old) components went into the family room for less serious listening. Very clever planning on my part, Eh?
This first incarnation of my living room stereo consisted of 2 Boston Acoustics satellite speakers and a single subwoofer. With a passive crossover, all the speakers could be driven by a single amplifier – a Denon 115 w/ch integrated amp. There was plenty of low bass, but it was not particularly accurate or well integrated between the subwoofer and the main speakers. I was deliriously happy at first, but as is the nature of this hobby, I eventually became dissatisfied with what I was hearing.
My subwoofer cabinet was not particularly well made and it was pretty large and ugly. Further investigations into the math behind speaker design, revealed that I could make a smaller, more rigid cabinet without significantly changing the low frequency cutoff or losing the flatness of the frequency response. For the driver I was using, a 3 cu. ft enclosure, gave a -3dB cutoff of 32 Hz or so and something like a 1 or 2 dB peak in the frequency response. This is really negligible when compared to the frequency dips and peaks introduced by room reflections. Also with an acoustic suspension speaker, the drop in response below 32 Hz was very gradual and I still had "audible" bass down to 20 Hz. The quotes around audible are because bass this low is really more felt than heard.
(I was able to test the response using CDs with test tones on them, my ears, and a sound meter from Radio Shack. This was good enough methodology for me.)
My second subwoofer used the same driver in a 3 cu. ft. enclosure made from ¾" Medium Density Fiberboard (MDF) which is a far superior material than particleboard for speaker cabinets. It’s very dense and heavy and creates lots of very fine, bad-to-breathe dust, but it makes great speakers. My woodworking was improving also. I got myself my first table saw and was able to cut the joints more accurately than on my first subwoofer. The joints on this subwoofer are all half lap rabbet joints glued and screwed together. I used several horizontal and vertical braces internally to the cabinet to give me a very rigid cabinet. I was more interested in sound quality than looks in these days, so I finished the cabinet with several coats of black enamel. I was hoping for a smooth, glossy piano finish, but it didn’t quite turn out that way. :-( It was a definite struggle to carry this speaker up from the shop.
About the same time, I decided to dump the passive crossover in favor of an active (powered) crossover. The kits from Marchand Electronics (http://www.marchandelec.com/) were highly recommended on rec.audio. An acquaintance at work taught me how to solder (Mil-spec quality supposedly) and so I built my own active crossover for about the same price as a passive crossover. I encased the crossover in a rather funky Plexiglass cabinet. It wasn’t all that inexpensive, though, because an active crossover requires separate amps for each frequency range. I bought an Adcom 60 w/ch amp to power the main speakers and used the Denon integrated amp for the subwoofer.
The active crossover makes it easy to modify the crossover frequency by switching plug-in chips. I tried several frequencies and settled on 75Hz. This gave me a reasonably flat room response, with no annoying bass boom like cheap speakers give, and a truly thrilling low bass on music that has it. (Try Bach’s "Tocata and Fugue in D" on organ).
By this time I was really going off the deep end in speaker building and starting to become very intrigued with woodworking. For my next project I decided to build my own main speakers (or satellite speakers). I discovered North Creek Music Systems (http://www.northcreekmusic.com), a newly formed company that sold high quality speaker components and kits. They also provided excellent cabinet designs for their different speaker systems.
I built their (no longer available apparently) Thendara system. This is a small acoustic suspension system using a 6" Vifa midrange driver and a Scanspeak tweeter. The supplied crossover system was very high quality and had a cutover frequency of 2000 Hz.
The cabinet design consists of walls of ¾" MDF laminated to ¾" plywood with ¾" plywood used for internal bracing. When finished the cabinets resemble concrete blocks. Very dense and heavy with no audible internal resonance. I also built a pair of speaker stands for the Thendaras out of pine. This is my own design and the hollow center post is filled with sand to further deaden vibration.
I still was a fairly impatient woodworker, so I finished these with a spray-on faux stone finish (Fleckstone?). It looks pretty good in a sort of industrial way, but it’s not exactly fine woodworking.
Thendara speaker with Subwoofer #1 in the background
I immediately fell in love with these speakers. They were everything an accurate speaker should be with wonderful imaging and clear sound. The bass went down to about 70 Hz and matching them to the subwoofer was pretty easy. For a time I was ecstatic. (:-))
I like to listen to music pretty loud. After I’d been using the Thendaras for a few weeks, I was disturbed to hear some high frequency distortion that I traced to one of the tweeters.( :-( )This got worse to the point that it was clear the tweeter was blown. North Creek readily replaced it, but the new one didn’t last for long either. I came to the conclusion that it was Luciano Pavorotti that was destroying these tweeters (probably "Non Piangere Liu" from Turandot). The real problem was the 2000 Hz crossover point, which requires the tweeter to handle a lot of power. North Creek sent me a pair of replacement Vifa tweeters which supposedly have a longer "throw" design. I also played around with the math of crossover design, and I modified the crossover frequency to about 3000 Hz. To my ears, this sounds just as good as the original tweeters and crossover and I’ve not had any more problems with blown tweeters.
The final step in my speaker building journey was to build a second subwoofer. I convinced myself that a second subwoofer would improve the bass in terms of room response and overall sound quality. In reality, I was looking for an excuse to build another speaker and to do more woodworking. The second subwoofer uses the same 12" woofer from ACI and has pretty much the same design as the first one. I added some more internal bracing and finished the exterior by laminating ½ " cabinet grade birch plywood to the MDF. The corner trim is red oak. I finished it with many coats of MinWax Tung Oil finish and was very happy with my woodworking.
Subwoofer #2
I’ve been content with this stereo system for over 5 years now. But my listening time has gone way down as I spend most of my spare time woodworking. My overall system consists of the modified Thendara satellite speakers, two subwoofers, two rear ambience speakers (from Radio Shack!), the Denon 115 w/ch integrated amp, Adcom 60 w/ch amp for the Thendaras, Marchand active crossover. For sources I use a Sony 33 (?) ES CD player, a Nakamichi tape deck, and a Rega Planar turntable. I much prefer CD to vinyl and I rarely listen to records or tapes these days. My blossoming woodworking hobby led me to build a cabinet for all the equipment, a Bolivian rosewood base for the turntable, and to replace the fake wood, vinyl covered particle board panels on the CD player with real cherry panels.
How does it all sound?
Stereo buffs with a lot of time and money in their systems can be very defensive about their own systems, so take this with a grain of salt.
I had the opportunity several years ago to help a friend select his own high-end stereo system. He ended up spending about $5-6K on a CD based system. We listened to speaker systems at various audio "boutiques" in central NJ that cost from $2K to $4K. Many of these left me cold. Most had no real bass to speak of. A pair of electrostatic speakers had wonderful imaging and high frequencies, but left off the bass I knew was there. A large pair of magnetostatic speakers had the most eerie imaging I’d ever encountered, but also missed out on the bass. The nicest commercial speakers we listened to, that did everything my speakers did, was a pair of Vandersteen 2Ci’s (I think that’s the model, it’s been a while). The bass was all there and they had pinpoint imaging and clarity. My friend ended up getting the more expensive Vandersteen 3 somethings, but I didn’t hear any significant improvements with these over the 2Ci’s.
I was prepared to end up unhappy with my efforts, but ended up pretty content. So if you like music and want a hands on experience, build your own!
