Volt-6 build thread

For those of you that don't make it over to the avsforums, I thought I'd re-post my Volt-6 build thread here.



So, I decided to retrofit my little theater's entire loudspeaker suite. I have been using a hodgepodge of speaker brands for the last 20 years (B&W 803s for LR, B&W FCM8 for C, Atlantic Technology 450SRs for surrounds, and Wharfedale Diamond 7.2s for back surrounds, 12" Dayton Titanic Mk III-based subwoofers).

The new LCR speakers will be JTR 228HTRs, the new subwoofers will be, first, a replaced driver in the 4 existing subwoofer enclosures (separate thread), and then later, a new big-boy sub to rule them all...

The surrounds? Well, that's what this thread is about. New surrounds, and the addition of Dolby Atmos speakers on the ceiling.

After browsing for suitable alternatives, the Volt-6 appeared to be the way to go. They have some great speaker designs over at diysoundgroup.com. Thanks, 'Erich H', for all you do...

So, I ordered 8 of those kits + flatpacks.

They came nicely packaged, with all the pieces-parts needed for a finished job. Even a PCB, so you don't have to worry about using pegboard for the crossover.

 

These little kits come in pairs, so I started with one of the pairs to test-drive the crossover assembly...



I immediately discovered that I needed to use my hotter soldering iron. I also learned a few things about the glue-gun operation... So, I moved on to knocking out the next six in one assembly-line operation:







Needless to say, I availed myself of the excellent advice provided over in the diysoundgroup forums here.

I added the connector wires, and then set about figuring out the best mounting location inside the box:



I settled on an orientation and location (you'll see it later), that would insure that it wouldn't interfere with the back of the driver(s) when they were installed, and then set them aside...

 

One thing that I toyed with would have been to use some hanger bolts to install mounting studs on the inside of the back panel. Alas, they don't make (as far as I was able to find) #4 or #6 hanger bolts... So I experimented with using a cut off #6 machine screw with a standoff...



Unfortunately, this didn't work out. Using a die to re-thread the cut off end of the machine screw wasn't clean enough to prevent the nut from turning the embedded screw (which only had its own threads cut into the MDF)... it turned into too much work. So, there's only one of these out of 8. For the rest of them, I simply drilled 4 pilot holes for #6 screws for the same location:

 

Note that for the most part, the flat pack pieces of MDF were clean and accurate (relatively):



Although I did run across one problem piece that would require some special attention later on:



In the grand scheme of things, however, not bad.

So, next, I set about locating and drilling the hole(s) for my speakon connectors:



I then drilled a 1/16" pilot hole all the way through each panel that would get one of these:



So that I could use my 2" and 7/8" (?) forstner bits to work from both sides. That way I would have clean cuts on both surfaces:



Unfortunately, when I went back through from the other side:



either my forstner bit was dull, or this MDF was not what I'm used to, because instead of getting a clean cut, I ended up pushing the material out:



Not good... This is the only one that this happened to. I ended up cutting the rest from the same side as the countersink, and not worrying about having a super-clean edge which was going to be inside the box anyway...

I used the 2" bit to clean up this mess, so now one of the speakon connectors will have to be shimmed up to the surface of the box. Oh, well. Live and learn.

[edit: Oops. I forgot to mention that I failed to mark and drill the pilot holes for the speakon connectors before assembling the box... That's a pain. Don't forget that step!]

 

For some reason, I either didn't take, or I misplaced, any photos of the box gluing step... I clamped up each box, and then used a brad nailer so that I could release the clamps and move on to the next box quickly (I only have so many clamps, after all...) Anyway, the eventual result was 8 Volt-6s, all in a row:



I'm a little disappointed about not having pictures, because I wanted to remark on, and demonstrate, the fact that the dado cuts and the sizes of the pieces (given that this was probably CNC'ed) could have been a little bit better. Also, one of the pairs of sides could also be dado-cut so that the resulting fit is solid. When building an MDF box of this sort, it doesn't have to be perfect, but I rely on having overhangs (from the dados), which allows me to sand just the end pieces to achieve perfection...

Having said that, the results are still very good, and completely within engineering tolerances ().

 

Then it was on to padding the inside. This is that thin, Walmart, 1/2" foam bed 'topper' (at 1/2", it's not much of a topper). Only $8 for a queen-sized piece, from which I was able to cut everything I needed.

Unfortunately, my electric stapler, with 1/2" staples, was too powerful for this material, so I had to resort to my manual stapler. Anyway, I cut a piece for the back, and a piece for wrapping around the sides:



And then set about getting it done:



stapling as I went:



And then cutting off the excess:



for a finished product:



They look like cute little coffins...

 

So, then, since this material was so thin, I opted to do without the PCB standoffs, and rely on the foam to provide clearance from the box, and tension for the screws:





And, Bob's your uncle:



I opted to install the crossovers and leave them in while finishing the rest of the build... They are removeable/reinstallable, however.

 

So, now to the baffle. First, drill the pilot holes:



Then, for gluing on the baffle, there are two options.

The baffle was cut (and routered) as if it was going to be installed on a flat (not slanted) front. This, along with the slight overhang that you end up with (after constructing the box), means that you have to deal with the problem at the top of the baffle, or the bottom of the baffle (or, both, if you try to split the difference). However, no matter what, the routered edge at the bottom edge of the baffle has to be addressed.

I decided to mount the baffle so that the the outer margin of the rounded edge (at the bottom edge) would be co-planar with the bottom of the box. Hopefully, this will be clear in the pics that follow. Also, I used my brad nailer to secure the baffle, and keep it from sliding, while the clamps are attached. First we have a completely clamped view:



And, now you can see the choice made for the bottom edge of the baffle:



So, the bottom will be sanded, as it must be, and this will leave a groove that must be filled at a later step. However, this will minimize the amount of material that must be removed from the baffle during the sanding step... that's the tradeoff, in my estimation.

Another clamped view:



So, the steps to get to the clamping result are, 1) glue:



2) position and clamp the bottom:





This keeps the baffle centered (left and right) on the box face.

3) Next shoot a couple of brads on each side, inside the routered countersink (couldn't shoot the brads, and shoot the picture, so here is the result):



4) Ready for clamping, and the baffle won't slide:





5) Wipe off the excess glue, and let sit for 30 minutes.

I know that Eric H suggested 'taping' the baffle instead of clamping, but, since I had the brad nailer, I figured I could keep the baffle from sliding, and stay with the clamping strategy.

So, all glued up... paper covers glued into place, and the port hole taped over:



Ready for sanding.

 

First sanding:









Next, some wood filler (I prefer the kind used for doing floors):



to fill in holes and grooves (like the one I mentioned at the bottom edge of the baffle):

 

So, all finished with the sanding, and ready for painting:



Note the clever use of the speakon countersink/hole for attaching a handle... some times I amaze even myself...

Spray paint the margins of the speaker hole and the speakon hole:



And, then, it's on to the DuraTex... I don't have any pictures of this operation, since I wanted to knock it out as quickly as possible. Here they are after the first coat:



And, the next day, it's back inside for the second coat:



and done!





I'll have a little more to say on the DuraTex.

Now, it's just the speaker and speakon installation left...

 

I completed a pair of the Volt-6s this afternoon. Pieces-parts all ready to go:



A final wad of polyfil for good measure, and in go the drivers:



And, by the way, the connectors on the woofer are a little too close to the mounting flange, in my opinion. It was a little difficult to get them to slide under the MDF. However, I was very pleasantly surprised to find that the woofer came with its own gasket, pre-installed... which is nice.

All done, and wired up:



I'm afraid that my critical-listening skills are woefully underdeveloped. For my first test, I simply replaced my two B&W (left+right) 803s, turned off the center, and listened to Back to the Future, III.





And, well, they sounded fine. So, then, I thought that I would leave one Volt-6 plugged in, and re-attach the other B&W, and see how that sounded... and, well, I couldn't tell that I had two completely different speakers playing... The sound was perfectly centered, and balanced, and well, it was kind of freaky. I should have someone blind-test me to see if I can tell which is which. Based on this little, informal, experiment, I might have trouble telling the difference!

But, like I said, critical-listening? Apparently, I'm not too discriminating.

Anyway, the bottom line is that they sound pretty good. I'll leave them in place until we get around to re-doing the entire theater (our son is coming to visit next week, and he's going to help me with all the heavy, and not-so-heavy, lifting).

- s.west

 

All finished, and here they are, on the stairway to heaven:

 

It's going to be a while before I have my act completely together (actually, we may be waiting a long while for that), so I thought I better put up a few pics, and notes about mounting, in case someone else is struggling with mounting issues.

So, for the ceiling mounting, we wanted to come up with something that would be rotate-able, and snug to the ceiling. So we tried the 6" angle bracket (Home Depot), along with a couple of strategically placed hanger bolts (#10 -24) and pads:







And, as you can see, the balance point turned out to fall right at the last hole of the angle bracket. So, then, after drilling a hole for a 1/4" lag screw in the right location on a ceiling joist, I took the bracket off the hanger bolts, put a fender washer against the ceiling, followed by the bracket, followed by a smaller washer and a 1/4" lag screw, and attached the angle bracket to the ceiling joist. We then re-attached the speaker to the angle bracket via the hanger bolts, and, voilà:



It's rotate-able, and within 1/2" of the ceiling...

I haven't included any pictures of the wall-mounted Volt-6s, since we just used a dual keyhole mount (mounted to the wall, with some washers for spacing), and a couple of matching flat-head 5/8" #10 wood screws into the back of the Volt-6. We put a couple of those little 1" felt pads at the bottom corners, dropped the flathead screws into the keyhole mount, and, again, voilà, wall-mounted Volt-6s. If you have questions about that, just let me know, and I'll post some pics.

Here's the little speakon distribution box I made (parts = ~$12, vs $120, off-the-shelf):





That's some 8-conductor 14awg speaker cable... for the 4 Atmos loudspeakers.

 

Performance-wise, these loudspeakers are a tremendous upgrade for me. As I mentioned, they are replacing a pair of Atlantic Technology 454SRs and Wharfedale Diamond 7.2s as surrounds, and adding 4 Atmos speakers.

These little speakers are great performers. I can't say enough good things about them.

- s.west