Jack of All Trades 8 Build

It's time to upgrade the mains and surrounds, and I thought I'd ease into horn speakers by building an inexpensive but solid horn for surrounds.

Key things I wanted to accomplish were:

Performance using known quantity components
Price - Grad student, annual 4 figures income budget
Looks - living room, WAF considerations
Sealed configuration
Size

After looking around, the best option within those guidelines was tuxedocivic's Jack of All Trades 8. At $95 a pop for components, and building a box & accoutrements, they're a steal! The dims are pretty close to 15.25x9.75x10.

Got the parts on order, then Pete and I picked up a sheet of oak ply and a half sheet of MDF from HD, and started making sawdust.

Components

Decided to try mitering for nice corners because I don't like plies showing...it's just not aesthetically pleasing to me, and I didn't want to merely slap Duratex on these.



Initially Pete was cutting them by hand, and the cuts were less than optimal, but then he decided to jury-rig a jig. As you can see above, to avoid plies showing on the back, Pete had an old roll of corner veneer that he put to use.



Meanwhile I was busy working on the MDF baffles.



Pete made quick work of the boxes. Pretty cool little hole cutter for the terminal cups.

Even cooler is that the miters worked out so well that Pete was able to simply tape & glue. The dado is for the single cross-brace that these will have.



I call this move the "Glue 'n Go"





Yep, there's four. I'm thinking of giving a pair away once done.



Just about ready to paint.



Dry fit. With gasket tape they should be just about flush mounted. Next build I think I'll rear mount similar pro speakers...they just look too sweet like that!



That's where we left it until next weekend.

Thanks! Mostly it's Pete's expertise. While I was doing the MDF baffles, he did everything else so far. That was good, though, as it forced me to figure out (or ask) how to do the recesses and cutouts. It took time, but the learning experience is invaluable. Plus, this was a weekend's worth of work.

By the way, MDF sucks to work with. Cleaning dust up, from the baffles on each router pass or the floor/workspace, took the bulk of my time.

I'm also excited to hear them. Maybe Saturday, if we can start early and bust ass on them.

I'm curious how sealed they'll be with the miters. If they fit really well together, it'll be great. The miters is also important because I cut the front baffles exactly to size with nothing to trim off! Hope it all works out.

If they suck, the M-80 idea sounds great! ;-) But, I'm sure they won't. Crossing fingers!

Mostly I just hope they fit the baffles!

Mobile update:

Got to demo these little guys for a solid 30min or so. First they were hooked to a little 20W USB amp and Pete's laptop. They sounded solid with great imaging and a good stage when on the bench just about a foot below ear level, toed in a little.

Then we hooked them up to a real power amp that did maybe 60W and they REALLY came alive. Superb dynamics and they remained composed, even with some fairly demanding content including Los Toreadors (via cd) from Carmen.

All in all they sounded superb for their size and price in the initial listening setup. Now for a little more in depth listening at home and cleaning up the finishing - had an issue with tape fusing with the duratex cuz we didn't wait for it to cure.
Edited by nube - 2/17/13 at 2:07pm

Finished these up over the weekend. A few pics, some commentary about the build, then later I'll post some thoughts about sound quality.

Left profile



Right profile



Back corner to show the miters and veneer.



This is a little deceptive. Where's the miter joint?



Overall a relatively easy build. Any complexity was added to get a non-DIY finish. I think that was pretty much accomplished.

The red oak ply didn't take stain too well. After the 2nd coat, it wouldn't get any darker. It's not a match for my previous sub build, but I still like the tone.

Side note: never using masking tape again. The stuff just leaves too much residue. Next build gets blue painter's tape. Also, gonna switch to spray poly.

The miters worked out pretty well, and the boxes look good. Just need to get grills built, then these are done.

Thanks for the design, tuxedocivic! Thanks to Pete for the equipment, space, help, and expertise! And thanks to Erich for the components.

More about the sound later.

Thanks man. Please do. I can prolly get some better shots with outdoor lighting at some point, too.

As for my listening impressions, here are a few notes I took the other day while listening to music:

Note: these comments are for the speakers without any MCACC room correction.

• Good stage when only moderately toed in, and waveguides at ear level.
• Full, rich, warm sound. Nothing too bright here. Maybe a little too far in the opposite direction, in fact.
• Surprisingly good lower end performance for the size.
• Not exceptionally efficient, but good.
• Music has some midbass punch even without a sub when set to Large in the receiver. Still prefer using with a sub.
• A little midrange beaming. Hard to describe, but on some very good recordings of classical, the cello can sound strained at moderate-high volumes.
• Vocals are similarly challenged on occasion.
• Like the size, though non-enthusiasts may still consider this a "big" speaker.
• Waveguides must be at ear level - seemingly excessive vertical off-axis performance drop.
• Even a 10 degree difference in height makes a huge difference in the high end (rolling off). Characteristic of this waveguide?
• Probably will easily exceed almost all user's needs for rears/surrounds in a HT, but not suitable for mains.
• They're good at what they're designed for - small, inexpensive and easy build with solid performance.
• Good little speaker to build for a friend who just needs a 2ch stereo setup for a living room.

They definitely were worth building! They're an inexpensive, small, good-sounding speaker. Exactly what I had hoped for!

Thanks for the input on the swapout of resistors. I may consider that after further auditions and after running room-correction on my Pioneer receiver.

As for the vertical off-axis performance, yep, I was talking about it seemingly rolling off the high frequencies. It seemed to me that it might very well be attributed to the dispersion pattern of the waveguides themselves, since they seem reasonably well-behaved when moving left and right, but less so when going much above or below axis. I live fairly close to a large park with a lot of open space, so I'll see if I can find a spot where there are outlets and perhaps measure them when it warms up a bit.