The Quad-4 Tripod (new Quad-4 build)

The Quad-4 Tripod

Since I'm about 80% done it's high time to report on my build of Erich's new Fusion-4 'Quad-4' speaker. These are my chosen surround and rear-surround speaker for a new HT where I'll have two for surrounds plus a single centre rear surround in the middle. My 15' x 10' space is too small for four surround speakers, so this slim line model is just what I needed.

Here's some pics of where I'm at so far. I dyed them to match the mains.

The Tripod:



Almost ready for bezels:



The inside edges are stained black, so any slight misalignment of the bezels won't be visible after I glue them on. This is because I choose to glue the bezels on after the main cabinets are completely finished.

If you're interested in my wood finishing steps, see my Fusion-8 'Alchemy of the Alchemy' build thread here: http://www.diysoundgroup.com/forum/index.php?topic=371.0 . I used the same method described there in detail.

Construction:
Again, 5/8" baltic birch plywood has been used, but this time I decided do 45º miters for every corner, except the bottoms which will be straight rabbeted joints. Turned out beautifully, however, I don't know if I'd ever do it this way again! Producing accurately sized panels and gluing everything up perfectly was way, way harder than my previous Fusion-8 build where I did straight 90º rabbets. Especially on a slim and long cabinet profile. Can't tell you how many times this speaker making newbie swore while making these cabs this way. And my next build, the Fusion-8 MTM, I went back to straight rabbet joints and was much happier.

I rabbeted out the bezels supplied with the kits all around their perimeter as well as at each brace location, to give a nice air tight and solid glue joint.

Here's a shot of the rear of bezels:



Closeup rabbet detail (5/8" x 3/16" dado):




Bracing:
The very narrow profile, I felt, required sparser bracing, so here's a couple shots of how I decided to go.

One X-brace between each woofer, and a simple cross brace behind the tweeter between the two side panels:



another brace shot:



Hopefully this minimal bracing is sufficient with the stiff 5/8" plywood combination. The cross-members are 1" wide. Tweeter brace about 3" long.


Dampening:
For the dampening material I switched to 1/4" 'premium' polyester fill tripled over:



All surfaces except the top and bottom panels are covered giving about 3/4" thickness total.

A closeup shot:



If you stick your face in the box and shout, there's quite a difference between the bare and dampened sound. How's that for scientific. I'm still finding this stuffing stage a step in the dark and have very little idea what I'm doing or what to shoot for. By 'premium' I think it means it's a little denser than the regular stuff. This is craft-store fare; not speaker supply store stuff, if that makes a difference. And, yes, I need to switch out the poster tacks with proper staples as soon as I can find a stapler that'll fit inside that pesky narrow cabinet...


Crossover:
All components were direct point-to-point soldered onto a thin 3 1/2" x 6" MDF board. Everything's hot glued down with zip ties on the inductors. And as you can see in one of the pictures above the board's located behind the tweeter smack dab in the middle of the rear panel. 1" wooden extensions had to be glued onto each end, since the board really needed to be 7" long to allow enough room for screws.

Here's a picture of my layout, if that helps anyone:




Well, that's as far as I've gotten for now. Hope to have the rest done in about a week, and will post listening impressions shortly after.

Comments, very encouraged as always...

 

Believing this is helpful to 1.4 people I'm gonna keep posting project updates.

I've been really busy on speaker crafting the last week and have finished the Quads!

Bezels sprayed and ready to glue on:



Yes, that's a Fusion-8 MTM center channel bezel too (another build thread coming soon...)

It took me forever to figure it out, but I'm really impressed with the finish quality of the bezels. It's a mildly textured look with a satin sheen and turns out super professional looking once you figure out how to apply it properly. Here's a shot of the products I used:



After much experimenting, I highly recommend sealing the MDF (especially the edges) first with something like the Zinsser "BIN" shellac base primer shown above. No comparison with regular paint primer which I wasted my time with first, and found it soaks in like water on the edges and doesn't do diddly. It would still take 3-4 heavy coats of the Tremclad texture on top before looking decent. Switching to the BIN stuff I found I could get away with just a single coat of Tremclad and it looked stellar. Highly recommended if you're not using a heavy DuraTex type of finish.

So, bottom line, the method I now use and recommend is (if you wanna go this route):

• coat of BIN
• sand lightly (edges more firmly)
• another light BIN coat (honestly can't remember if I did this or not....sorry!)
• 2 light coats of Tremclad texture within 1 hour (no sanding between). Don't hold can too close or you'll get shiny streaks.

Installing the drivers:



The factory cutouts for the 4" drivers are too small! You can press them into the unpainted MDF okay, but once you apply a few coats of finish you're in for some trouble. You can see how the paint scraps off trying to force them in, and I had to literally use a rubber mallet to drive them home. Not only that, but the frame face warped significantly after I tightened the screws down, and I bet the foam seal at the bottom is no longer sitting flush on the recess because of this. I need to advise Erich of this and hope this can be changed for future factory runs. If you're careful with your paint build up, or if you carefully dremel it off before installing the drivers, you might be okay though. Cosmetically, adding an extra 1/32" to the cutout radius wouldn't be visible past 12" away and would make a world of difference, I think.

The horn cutout is perfect, though. Unlike the other kits, no foam seal was included for the inside of the horn frame, so I added my own to ensure air tightness. Easy peezy. Didn't take a picture of that part.

Now I'm finally finished!

I just think these are the coolest looking little speakers. So, I ended up taking a ton of pictures and thought I'd share several for those interested.

Front "beauty" shot:




...another angle:




Rears:




As a center:




Closeup:




How 'bout this idea for a center channel??? (kidding...

 

Here's some in-room shots to help get an idea of what they'd look like there (test positioning only):






...and as surrounds:




...with Fusion-8s:

 

Thanks. Mitering wasn't fun (at all).

Rona, in Canada, but I'd guess Rustoleum products are widely available elsewhere too. If you use it, keep in mind it takes at least a few days to harden properly. I wouldn't think to install drivers for at LEAST 2 days (4-5 better).

 

My first experience was with watching a DTS movie with them setup in stereo-only mode and no center channel. I was very impressed! Within 5 minutes I stopped critically listening and got lost in the movie. I kept telling myself, oh yeah, I'm supposed to be listening for faults, but kept getting immersed back into the movie. that tells ya something.

They create a very interesting sound field which I think is a great movie immersion experience. Literally, its like a mast of sound extending like a big sheet between the speakers and way up into the air above the TV set. I stood up on my couch and it sounded virtually the same as seated! These speakers are a treat for those guests or family members sitting on the ends of the couch (or even in chairs beside the couch). So, for one thing, if somebody doesn't have lots of space, or desire for more than two speakers, but wants an immersive 'movie experience' I think the Quads really deliver.

And, boy, do they reach for their footprint! Here's a video I made during a scene in Prometheus running them full range and moderately high volume:

http://youtu.be/d74zQ40oJWM

Look at the extension on em tiny drivers Fun to watch, but besides that they have surprising grunt. Below is a comparison of the Quad to the Fusion-8 Alchemys I made:



Ignoring those wild room-effect swings you can see the Quads indeed appear to have more bass energy than the Alchemys, and extend higher. Audyssey EQ says so too and wants them crossed at 40 Hz (compared to 60 Hz for the Alchemys), just for comparison's sake.

(NOTE: while the FR plots were done in identical settings, the Audyssey EQ test was done in a completely different room.)

I haven't done a ton of critical music listening yet, nor got more than a couple movies under my belt, but right now, I wouldn't hesitate to recommend them!!

 

Well, the Quads have really changed in 3 days. Here's an updated comparison with my Fusion-8s:



So, you can pretty much disregard the plot in my post above from 3 days ago, as far as the Quad vs. Fusion-8 comparison. They are more cohesive and less boomy-sounding now.

Looking forward to the next few weeks break-in!

 

Thanks, maxmercy. Fun project. The plot was with no EQ. 1/3 octave smoothing, so quite forgiving, but even @1/6 it honestly looks much the same. What's even more impressive, though, is that the living room pictured above is not the room I did the measurement in (unfinished HT). The HT is even harsher, acoustically, with no furniture, laminate cork flooring and no carpet. While I don't have a living room plot of the Quad @1m, I did do one of the Fusion-8 Alchemy in both rooms to compare, and the living room plot looks a little better for that speaker. So, yeah, I'd say the Quad has a pretty flat in-room response.