My Speaker Project, and Thoughts on a Businesses Liability Kills

I am in the process of building some speakers for my home theater.  This is something I have never done before, but the idea has always intrigued me.  So much so I have actually played around with software and designed a lot of cabinets and crossovers, but never built them.  I am finally going to build an L-C-R for my home theater, and since they go behind my projection screen (the screen is perforated for sound transmission, just like in movie theaters) the pressure to produce flawless cabinetry is reduced significantly.  In fact they will probably be built out of raw MDF finished in black, though I will try to make them look nice just for the practice.

Anyway, one of the reasons I have put off this endeavor is that I do not own a some of the key tools, and do not have the space for these tools.  I have a nice router, belt sander, jig saw, etc.  but I do not have, and really don't have the space for, either a table saw or a drill press.

Which led me to wonder if folks had well-outfitted workshops that they lease out by the hour for such work.  After all, with a good plan in hand, I probably don't need more than an hour on a table saw to get what I need -- most of the project will be in routing the speaker holes and counter sinks, assembly, and sanding/finishing which I can do at home.

Of course, I could not find such a thing.  I could not even find a storage locker that would let me use it as a work shop.  Thinking about this, I am not surprised.   No matter what I get a customer to sign, now matter how well maintained the tools, if someone cuts their hand off using a tool in a stupid and careless way, there is likely going to be a jury somewhere that still wants to assign me liability.

My readers tend to be very nice about rushing to help -- I got about 10 emails offering to help me with my server migrations.  I turned them down because part of the point was to learn to do it myself, and my learning process tends to be by trial and error doing things myself.  Anyway, please do not offer me your shop -- I have found a local community college that allows its shop to be used after one has completed a training and familiarization course (which seems a reasonable precaution).

I am excited about getting started, and am just starting to accumulate the materials.  BTW, in case it becomes relevant to you in the future, a full 4x8 sheet of 3/4-inch MDF is really heavy.

Postscript: I will let you in on my secret ambition.  I really, really want to build a pair of line arrays, as much for their shear bad-ass looks as anything else.  Of course, my wife would freak and I am not sure where they would go in my house, but someday....

  • Ugh, speaker design and building is a black art. Folks use a variety of measurements to quantify things, but there are an awful lot of little things that can go wrong and mess up your end result. Experience and accurate measurements are the only way to get good sounding speakers, neither of which is easy or inexpensive. Kits are a far more reliable way to get good sounding speakers than designing from the ground up.

  • James H

    I'd recommend rabbeting or dadoing (just turned nouns into verbs) the pieces together also. This really makes it easier to put it together and also makes it more rigid. I've built some subwoofer boxes for cars with only a circular saw, jigsaw, router, long straightedge, c-clamps, and hand drill with decent results. A table saw would really make it easier, though!

    Also, if you don't need long panels, I'd recommend getting the 4 x 2 foot pieces you can also usually get at the home-improvement store. Easier to handle/transport, etc.

  • perlhaqr

    Yeah, I had some friends in San Francisco who owned an auto shop where you could rent time on a lift, keep project cars, etc. I was astounded that they could afford the liability insurance for such an endeavour, especially there.

  • DensityDuck

    You could probably do the "tool garage" thing as a private club.

    That is, of course, assuming you don't just have people pay you cash under the table.

  • A specialty lumberyard would probably cut the pieces to rough size for you. Then it would be a matter of joinery and finishing which are the good bits of woodworking anyway. Though not a fan of MDF for most applications it is actually probably a very good material for speakers. It is very stable and strong. Gaps that appear later would really damage a speakers sound. Check out the wood forums like charlesneilwoodworking.com, lumberjocks.com, and http://www.sawmillcreek.org (pay to post on the Creek). There are lots of resources available and you should be able to find what you need without the tablesaw, etc. Feel free to e-mail me as well, I am not a woodworker but I know a lot of them in my business.

  • Anna

    I think what you're looking for is a hacker space. There is a list of hacker spaces around the world here http://hackerspaces.org/wiki/List_of_Hacker_Spaces

  • txjim

    MDF is a pain to work with. Too dang heavy and the brittle edges will test your patience. The saving grace is it looks great once you are done with it.

    A great tool for anyone without a table saw:

    http://www.amazon.com/Bench-Dog-10-019-Portable-Circular/dp/B0007VO0GM

    I tried to find the awesome Bench Dog plywood jig I bought 5 years ago but no luck. Here is a similar DIY rip fence that is handy to have:

    http://wayneofthewoods.com/circular-saw-cutting-guide.html

  • Nick

    What you need is a friend with a shop. Don't turn down offers from people- you could be missing out on a lot, like new friendships, learning new skills or techniques, etc.

    One of my favorite things to do is work on projects in a garage with friends. They don't have to be helping you with your project, either- they probably have their own to work on. Sometimes you need an extra hand to get something into place or hold a clamp- friends are great for that.

  • supermike

    Apparently Phoenix has a nascent hackerspace, and they either have or want much of what you need http://www.heatsynclabs.org/wiki/Wishlist.

    I want to build a set of electrostatic speakers.

  • Mesa Econoguy

    I want to build a set of biamped plasma speakers bigger than washing machines (front), with full-range Leslies for surround (rear).

    Screw the line arrays. Coyote, what you really need is a full set of these (with separate amps):

    http://www.bowers-wilkins.com/Speakers/Home_Audio/Nautilus/Technologies.html

  • Highway

    Oh, B&W speakers make my heart ache. I just love the sound, even from their bookshelf speakers.

    My prospective 'cabinetry' project is much more down to earth: Travel rack boxes for PA equipment for my band. The prices on the premade ones are ruinous.

  • Craig

    Build subwoofers They are necessary to take the load off your LCR speakers and they can be much smaller (easier to build). You can't go wrong with Sonotube subwoofers, particularly when they will be hidden behind the screen. Sonotube is a cardboard tube used to form concrete and is available in many different diameters. As a cylinder, it is an ideal enclosure for long (bass) audio waves. YOu also will not require a lot of tools.

    Here's an old web site that summarizes the advantages of Sonotube.
    http://www.lungster.com/l/speakers/sonotubefaq.shtml

    The best single site for do-it-yourself speaker projects is the AVS Forum's DIY Speakers and Subs Forum:
    http://www.avsforum.com/avs-vb/forumdisplay.php?s=8297e317aa92c97e78638b999dcf5af8&f=155

    You can probably get any question answered with the search function, or as a last resort posting. (I think you have to register to use the search function or to post, but it costs nothing). Also, check out their power-buys. Vendors will sometimes offer specials to AVS members. I got a fantastic deal on five powered Berkline recliners.

  • Craig

    I forgot one great site for kits - Zalytron. http://www.zalytron.com/

    You can get plans; plans and speakers; plans, speakers and crossovers; or plans, speakers, crossovers, and enclosures. Don't be afraid to call and ask for help. Elliot usually answers the phone and is extremely helpful. You might be interested in the Joe D'Appolito (a name you should recognize!) designed arrays. Here's what Elliot says:

    "We asked Joe D’Appolito to design some new line arrays for us. We wanted to build these arrays with high quality parts and yet be somewhat flexible in the price range. To accomplish this we have designed a total of 8 different versions. All use the Raven R-2 tweeter. The mid base drivers are either the Focal 5W4252 or 6W4254 W-coned Utopia units. Joe designed these arrays in such a way that you have the choice of 4, 6 ,8 , or 12 mid base driver with one R-3 tweeter. The 8 and 12 driver versions benefit from Joe’s driver weighting scheme. The outer drivers are driven at a lower level to reduce the interference that is caused because they are farther away from the listener. Joe first tried this in the Axon arrays and our customers love them. First impressions of these new arrays are that they are a big step up from the Axon arrays."

    The Raven ribbon tweeters are great! I am using the smaller R-1 in my LCR speakers.

  • I have built cabinets that will stand up against the best commercial grade stuff without the use of a table saw. A good hand circ -- even a 7.25"-er, if you get a good one -- with a high-end blade will, if guided and handled well, will deliver cuts as or more accurately than any table saw, and with less work, as you're moving a saw that weighs 8-10lbs as opposed to a big sail of plywood that weighs between 30 and 50 pounds. If those cuts won't satisfy you, get a 1.25" straight router bit and a self-clamping straight edge and refine your edges just prior to assembly.

    I use one of two corded 7.25" -- a Ryobi and a Porter Cable, neither particularly remarkable -- with Freud Diablo blades. (Teflon-coated.) I spritz a little WD40 on the blade before each cut.

    For support, I use a pair of Work Mates, bridged by sacrificial 2x4s. I hold the work piece(s) in place with a variety of clamps as appropriate.

    I work alone, with no assistance, and the end results, as I say, will stand up next to high-end commercial grade kitchen cabinets.

    I would second the thumbs-down on MDF for much the same reasons.

    M

  • Dan

    Straight edges cant be stressed enough - you'll experience a bunch of loss in terms of cabinet resonance if the edges arent square and well seated to one another!

    I'll second the sub idea - your ears cant really detect much directionality below 150Hz or so! Few years ago I built a couple replica models of the bose acoustimass design to very good affect - obscuring the speaker cone from the room really introduces another layer of obscurity to the equation, result is very omnipresent and non directional (=huge) bass response 🙂

  • ScottE

    1) I've come to despise MDF due to the mess it makes, the toxic dust. I've moved to baltic birch ply, which you can get at hood distribution between sky harbor and I-10. It's not a whole lot more expensive, is stiffer, and many believe sounds better. The 3way cabinet I just tested for XO design, I couldn't feel the baffle vibrate at all when exciting the drivers.
    2) the two main tools you need are a saw and a router. Consider one of those dewalt track saws if you don't want to take up the space of a table saw
    3) post at the parts express tech talk forum to see if anyone can help, there's a fair sized audio diy community in AZ. I'd lend you the time, but i'm in Tucson, and you think I'm a racist.
    4) there will likely be a diy speaker event in the near future, probably in Tucson (but on the northwest corner of town, so relatively accessible to PHX people). Email me if interested.

  • Matt

    Not being an audiophile, I pass over most of the comments, which are about speakers, and simply thank you for posting your solution (the community college), which might prove a viable alternative for people in other places with different ideas that nevertheless encompass the same fundamental problem. 🙂

  • EarlW

    I built a set of 'folded transmission line' speakers out of 3/4" veenered plywood. KEF woofers and some second-hand London Decca ribbon tweeters. The local high-school rented their wood shop in the evenings. It was well equipped. A few years later, I found a friend who allowed me to share/rent his woodshop for other projects. He was also a wood-shop teacher at the local college.
    I still have the speakers in the garage, collecting dust. I have no idea if they still work.

  • T J Sawyer

    Agree wholeheartedly with using the circular saw. Clamp a guide in place, nothing cuts more accurately. Spend $60 on the blade though. Will give you cabinet quality.

    For subwoofer: Just build a 2 ft by 3ft by 4ft box out of 3/4 in plywood. Bass reflex design. Put in the heaviest magnet 15 inch speaker you can find and a rectangular port of equal area. Lots of fiberglass and bracing. In 50 years I haven't found a speaker that can touch it! If you have the room, it is the only way to go.

  • dSound Pro

    Making your subwoofer sound like a million dollars is what the 15 Inch Subwoofer Box by QPower is all about and it is also sold at a fair price.