Building the Zaph Audio ZA5.5tt - MMTMM 2.5-way Vertical Array

[PanamMike]

So I built the Zaph Audio ZA5.5tt. It was my first DIY speaker project.
Definitely the best speakers I've ever owned. Much better than the
Kevlar-coned Bowers & Wilkins that are built into the ceiling of my home
or the $1800 THX set I used to use for HT.

I'm surprised with the performance of these speakers. As far as clarity
of movie dialog, they outperform my headphones in A-B testing. Sure, I
wanted to have speakers but I thought that my headphones would still let
me hear dialog more intelligibly. I didn't expect that any speakers
would do that better than headphones. These speakers also have enough
bass for my music needs. I was concerned that I might still need to use
my subwoofer since the room is quite large(26 feet by 36 feet) but a sub
won't be necessary, so I can donate my old subwoofers to Good Will.

Reasons I picked the ZA5.5tt:
1. It was the lowest cost DIY product that gave me hope of having
performance I'd be happy with. Total cost of everything was
less than $600 for the pair.
2. John Krutke's posts and website gave me the feeling that we had
compatible engineering sensibilities.
3. It was the largest physical size speaker that I any hope of
having my wife accept in the living room. They are 8" wide. I
went with the ZA5.5tt instead of the ZA5.3 since the ZA5.5t uses
the same amount of floor footprint yet has twice the extra bass
radiating area.

What I learned:
1. Butt joints are fine. I make furniture with dowels and planned
to do that, but when I got out my dowel jig, I saw I was out of
dowels. Since the MDF cuts were fairly precision from the store,
I just used lots of clamps and tapped the MDF pieces into
position with a rubber mallet and then tighten the clamps.
Doweling would have been a waste of time.
2. It's OK not to buy the whole accessory kit from Madisound. I
bought just drivers/crossovers plus foam, port tubes and peglock
grill fasteners(wifey requires speaker grills though the design
is specified without them). The port tubes aren't flared and
require a good bit of time to remove the excessive casting flash,
but are convenient all the same. The Zaph design shows flares,
but computations suggested it might not be necessary. I did not
buy the $1.25/foot wire Madisound suggests. I used some 14 AWG
wire that the previous house owner used to wire some exterior
speakers near the Jacuzzi. I did not buy quick connects but
simply soldered directly to the speaker lugs. I shielded the
speakers from the process while soldering with sheets of paper.
3. I didn't need a plunge router. If the guide hole of the circular
jig I used was close fitting, I could plunge a stationary router
well enough by hand.
4. It's hard to get veneer perfect, but it's not too hard to get it
good enough even just using Tightbond wood glue. It's all about
getting the right amount of glue(too much causes wrinkling and
too little means fixing up all the edges). Despite that my taste
is solid wood, monolithic veneer is quite endearing. It was my
first experience doing veneer. Next time I might consider an
iron on glue. I was very happy with this source for raw
veneer: lepkowski of ebay.
5. 3M Super 77 is great for gluing the damping foam to the inside
of the cabinets.
6. Textured Rust-Oleum(#7220830) doesn't hide surface scratches. I
should have sanded and sealed before applying like I would have
done had I carefully read through John Krutke's advice on this.
7. Phasing the tweeter was confusing because I expected that I'd
have to reverse the phase because I thought it was a 2nd order
crossover. Anyway, they're wired in phase as the diagram
indicates. Ultimately, I just followed the directions carefully
and didn't try to out-smart the documentation. I did check the
woofer phasing -- all were correctly marked.
8. Using linseed oil finish on cherry veneer, it took 6 weeks total
time to let the oil cure between coats. Building my own
speakers took a lot of time, but I enjoyed it.

The final weight of the speakers is 59 lb each. I followed the enclosure
drawing best as I could, scaling the drawing for the port and internal
brace locations. I didn't fill the base with sand or kitty litter because
that is were I put the xovers, since the Madisound xover PC boards don't
both fit onto the bottom piece of MDF. Right now they're just resting on
dense felt pieces to protect the hardwood floor, but eventually I will
museum putty them to the floor for earthquake proofing.

Anyway, this is my first post, too. I found this group because I
sometimes Google LTspice to find how it is used(I'm the author of that
simulator). I'm contributing this post out of gratitude of the advice I
found looking through this forum. While this was my first DIY speaker
project, my wife tells me it's also my last, so I don't see that I'll
continue to be particularly active here.

Thanks are due to John Krutke for this awesome-performing speaker design.

--Mike

[crazyhub]

Impressive. Bravo!

[tuxedocivic]

It's your last DIY speaker

[blue934]

excellent job! glad to hear that you're pleased with the outcome. lot's of discussion on these mmtmm's but it's hard to find a review from someone who has built them.

david

[RockLeeEV]

Thanks for this. I've always wanted some third party opinions on them.

P.S. what are your headphones?

[PanamMike]

Blue934 & RockLeeEV,

> ...it's hard to find a review from someone who has built them...
> ...I've always wanted some third party opinions on them...

Yes. Halfway into the project I realized that I had never heard
a review from an ordinary DIY'er(or newbie)and wondered what they'd
sound like. I was reassured from a guy with more audio experience
then me, though, that I would definately like them.

> P.S. what are your headphones

Sennheiser RS 120. They have quite reasonable performance
with dialog, certainly better than my built in B&W's or the
$1800 THX system, but not as good as these Zaph speakers.

BTW, I have no association with John Krutke. We've never
communicated -- he doesn't know me.

--Mike

[tuxedocivic]

I just recommended these over on another forum, I'm going to link your review.

[blackoper]

Thanks Tux for the link. Thanks PanamMike for the review. I'm glad to hear they sound great. I'll probably build some here in the next few weeks

[imstillatwork]

Nice! Can't wait to finish the 5.3 MTM's to go with the center and 5.2 I'm using now!