To Buy or to DIY, here is my question

chorus,

As many have said, DIY speakers can be rewarding, frustrating, a great learning experience and worth it in the end.  Mine, basically a modified Altec Model 19, took longer than I planned to get all the details right and allow for a learning curve, but I’m pleased with the end result.  

Since you’ve been doing some research, you probably know these things, but here’s what I learned along the way.

Cabinets:  

Mine are 3/4” 11-ply void-free Baltic birch - see my Audiogon aviator, or whatever you call it.  Not having the ability to make fancy carpenter joints, corners have 1-1/2 inch wide 3/4” Baltic birch strips used to brace all around the edge of the sides/front/back and then pocket screwed into top and bottom pieces.  Also a complete circle around the middle which is tied together with a brace that goes from front to back.  

Diagonal pieces on sides, front, and back to dampen cabinet resonance.  Lots of glue and wood screws and then all corner seams caulked.  

Back is removable, (required as the woofer is rear mounted and I wanted to have access to tune the ports), and attached with threaded inserts and machine screws every 3 inches.  Speaker gasket keeps the removable back air tight.

I cut each piece as best I could with some margin to spare and then took them to local cabinet maker to get everything matched and square.

To add some dimension to the look, the sides are recessed 3/4” on the sides and 3/8” from front and back edges.  The front and back panels are recessed 3/4” from top/bottom edge and 3/8” from side edges.  Speaker and port cutouts edges are beveled.  Not everyone’s idea of good looking, but better than a plain wooden box.

Danish oil provides a nice and durable finish without brush marks.  Others have suggested spraying the finish on, especially if a color is used, or you can build the corners flush and then add veneer depending on what you prefer.  I needed mine to be simple.

The cabinets are each about 85 pounds without speakers, air tights and rock solid, yet still manageable to move around.

Regarding insulation inside the cabinet, follow the speaker manufacture’s recommendation.

Crossovers:  

Nice to be able to choose capacitors based on their sonic characteristics.  As other’s have said, it is very important so use a proven circuit for those drivers and the cabinet type and size they will be in.  Does Madisound have a crossover for these specific speakers? 

Use point-to-point connections with the capacitor, inductor and resistor leads as much as possible.  Use compression type connectors if you need to vs. spade connectors, (takes an extra solder joint), if all connections can’t be soldered.  

Solid core wire is much easier to use for short pieces to be “shaped” in tight quarters, to have clean ends and get a good solder joint.  Lots of opinions on wire size, but 20 gauge for short lengths in crossovers has been what those who know much more than me have suggested and worked great.  (You might be surprised to see what manufactures use vs. bigger is better notion.)  I did go 18 on woofer connections because I had it, but many output transformers in tube amps use 20 gauge on short leads to speaker terminals.  

Use stranded of course for wire runs to the drivers, 20 gauge is plenty for mid and HF drivers.  18 gauge if soldering to woofer; thicker wire can wick heat making it hard to get a good solder joint.  I’ve found quad eutectic silver solder with rosin core to give best results.  

Good luck, and let us know how your project goes.

lemonhaze,

I smiled when I read you comments about the importance of the crossover being so important and laughed when you recommended the Altec Model 19.  So I accept your statement that great minds think alike!

The cabinet houses only the woofer and a slightly taller and smaller version of the ALtec 620 cabinet.

My crossover is the Zilch Z-19.  As you know, he separated the woofer in the circuit since it didn’t need the L-pads.  That crossover is mounted in the cabinet with proved cap and inductor.  The HF portion is outside so I could try different capacitors.  Started with affordable Solen PB-MKP’s to figure out a layout and in case I messed something up.  Sounded impressive.  Coincidentally, today I finished a new HF crossover build using Jantzen Superior Z-caps and Mill resistors and the improvement - to my ears and for what I was looking for - was very rewarding.

As you know, Zilch was the mastermind behind the Econowave.  His posts were very helpful throughout my DIY project.  What speakers are you running theses days?

chorus, 

So if you go the DIY route, look up some of Zilch’s posts for general build insights, regardless of what speaker design you go with.  And if you decide, now or later, to build a high sensitivity speaker with it life-like dynamics, (and ability to tame the highs with the right gear), you could build a set of Klipsch Chorus for your name’s sake.

Enjoy the music.

chorus,

Not to get off subject, but if you’re going to have your tools out anyway, a simpler DIY project with much higher return on investment vs. store bought is building your own acoustic panels since the room dimensions and how it’s acoustically treated will have the biggest influence on how your speakers end up sounding.

GIK Acoustics carries Knauf’s ECOSE material, much better to work with than fiberglass, and some Guilford of Maine acoustic fabric gives you top quality components.  For frames, use premium pine one-by (3/4” actual thickness) trim the appropriate width and assembled with glue and pocket screws.  Get fancy and add some gussets in the corners to help position and hold the material and you’re good to go for absorption treatment.

lemonhaze,

Very impressive cabinet build - no plain wooden boxes there!  Enjoy your Tannoy project.

chorus,

You obviously have more experience and knowledge than I did when starting audio DIY stuff, so I’m sure what you do will be a success.

Given how many acoustic panels you built, I image you have some on the ceiling.  Since I had horns for the upper frequencies, I figured their vertical directional control would be sufficient.  But bass traps in four corners and first and second reflection point treatments making the type of difference you experienced, added some for the ceiling’s reflection point.  It was so helpful I added two more behind them - not as much of a difference, but still worth it.

I don’t have experience with sealed cabinets, but did appreciate the ability to tune the ports on mine - I used two 4” round ports with adjustable length tubes vs. the cutout in the baffle Altec used on the Model 19.

“perkri" offered some good advice and port tuning is another way you can tailor things to your taste you can’t do, (or nearly as easily), with store bought.

With the Altec Model 19, some said raised the tuning frequency of the Altec 416 woofer enhanced the midrange with a just a little sacrifice of low frequency reach.  Sounded good but preferred the balanced sound with cabinet tuned to Great Plains Audio’s suggested 29 Hz - just 4 Hz difference.

You’re right on the mark about multi-directional bracing in the cabinet, especially front to back in the center.

You may already know which capacitors you'd use, but in case you didn’t see this article: https://www.humblehomemadehifi.com/Cap.html.

After trying 3 different caps, the descriptions he gave were quite consistent with what I heard and a noticeable improvement over stock grade.  

There’s snow on the ground here, but my JBL 29AV speakers do a decent job taking care of outdoor music.  Still, you’re right, there’s nothing like a large, high efficiency speaker with proper power played outside, especially with a well recorded live album.  So enjoy your music indoors and out.