Here's a pic of the speaker box... I've set it up so as I can change the front
panel to try a variety of drivers. Initial set up will be 4, 8" woofers I've
had lying around for  a little while now.
Gaz

I haven't yet painted the outside of the cabinet and finished all the trimmings,
but there are only a few more hours work left to do. Fired her up of course and had
a quick listen, not too loud . The Half Imperial still goes deep, plenty of
twenty hertz stuff vibrating various items on the patio, even more at thirty hertz.
Musically, she has a good spread across the audio range. It would be interesting
to do a few tests in that department. Vocals are clear, and even cymbals are
quite audible, though I feel the SPL is dropping off around 8000Htz or so.

But enough of the tech talk for now. My only dissapointment is that I didn't build
a stereo pair. Sizewise alone, they are a more civilised version of the 'Full Imperial',
and still deliver (though at a more reduced SPL). As they are, they will be
suitable for my son's guitar, or for that matter any stage application. I'm looking forward
to trying different drivers. The current 8's are garden variety cheapies, better
ones are on the cards. At a pinch, I may be able to squeeze in 4 x 10"s, possibly
2 x 12"s. We shall see .

Until then, here's another pic, with a certain item to give it some scale.

Cheers,

Gaz

VERY COOL!
Explain please how it is half?
All heights different in the pic with the beer bottle. And it seems much narrower. Mouth is not square but what are the mouth dimensions? Or is it indeed all the same just cut in half down the front view?

Hey 60, I checked out your totally cool clip a while back and I'm still laughing  ;D
I've just shown it to the family and they reckon it's totally cool too! From the looks it's about 1:4 or 1:5 scale? I'm tempted to do the same, maybe a 1:10 scale and fit a AM/FM radio in there, just for fun. Maybe we can have a competition to see who can build the smallest, functional,to scale Imperial

Hey Chris, allowing for the fact that I was using 18mm chip instead of the preferred 3/4" ply, I cut the speaker chamber braces to size, and used a ratio of 18.5/19 x 'Decware Plan' to give the appropiate horn dimensions.

This gives me a speaker 7/8" shorter and 3/8" shallower than the plan. The width of the box is a whisker less than half the true Imperial.

A single jarrah wood brace secures the rear of the horn, and is a nice touch too. Eventually I would like to use a fine piece of jarrah ply for the 'speaker panel'. This is one item that will get extra reinforcement in the shape of some angle iron braces. The speaker panel is all holes and can only benefit with some extra stiffness.

I agree Simon that a lighter colour on the outside of the box would be a good contrast to the dark interior, but I'll probably finish the outside with the black hammer finish, if only to match my existing speakers and in keeping with a common theme.

Looking forward to seeing your SO. Looking good.

For those who have forgot, here is a pic of my original Imperials...

Hey buddy!
I wonder if the FS was lower it would play lower. It would be interesting to try a single 12 with a Fs lower than 30.
John in C.R. did some sims with a half IMP as a sub it was looking favorable. A low Fs full range 12 always interested me in a half Imp.

And for now, here is the finished product.
Oh, I picked up a sheet of Jarrah veneer that is big enough to cut a
panel for the 4 x 8's and (this is what lights my candle), a front panel
for 1 full sized Imperial., plus a few lengths of 2x3 Jarrah for the back
braces. In other words, the full sized Imperials are a goer, though it maybe
sometime before I start cutting wood.

I'm considering the following, a 15inch woofer, sandwiched by 4, 8 or 10 inch
drivers. Hmmm Like I said in an earlier post, I'll check out various drivers
in the half Imperial and see what delivers.

"Dank's" article 'Interesting twist for an Imperial' gives us some idea
as to what can be achieved (definately worth another read). The Decware Imperial
concept of using mismatched 15" drivers in the cabinet may find its nirvana in the
not only mismatched, but mis-sized driver scenario.

Of course, the immeadiate queary from wife and friends is...'where are you
going to put them?' Ahhh, leave the fine print till later huh. You guys know what I mean.      

Oh okay, here is one more pic of my woofer.
Actually it is my daughter's woofer which I seem
to have adopted. Not a bad lookin dog for a
chihuahau, at least that is what my daughter
was told when her boyfriend bought him.

You're leaps and bounds ahead of me.  I haven't done that much more than what I've photographed.

Too busy at work which is leaving me tired and unmotivated to go out to the garage.

Let me know what excuses you came up with regarding placement of the horns

Now that I have seen your work, it can be done with the expectant
results. Obviously, I'm not expecting any smaller scale designImps to
to knock stuff off shelves in the neighbor's house next door, but should
sound beautiful and full non-the-less

By the way, did you document your effort , so it can be refurred to help
someone else scale their Imperial design down

Your modifications of Steve's plans for your half scale Imps design are a helpful reference. I'm sure he wouldn't mind....But will ask first before moving forward on my request for help in this area

That'll work....I get the plans and then we can go from there, Thanks!

Got the plans. Been comparing the inner baffle section of the '59-'63
plan to Decware's modified version....The modified version has a
more open inner chamber I noticed.

I'm staying with the 3/4"(19mm) plans

Definately, not the backseat of a vehicle....Except a motorhome!
Bedroom is out of the question. A large recreation room will work
as a sound space.
Did you scale down the inside baffle chamber, or did it become part
of the upper chamber space where the throat begins?

I gave up using smilies for a while.
Anyway, I blew up portions of the plans to see what the
various messurements were and figuring the gap width of
the inner chamber vent.....I think it's one inch it looks like.

12" Electrovoice Wolverine(s) Co-Axial(s).
I have a pair of 8" Wolverine Co-Axials That
may sound impressive in such a cabinet design.

Hi Guys,

I have built 2 half-Imperials and use them for live music.  I simply cut the plans in half, taking into account the thickness of the material I used (3/4").  I have used the speakers separately as 2 mains on either side of our stage, or as one speaker(both halves placed next to each other).  When used as one, they basically act like one full size Imperial, which was my intention (I have a second full size imperial also).  As individuals, the half-imperials sound good but don't have the low bass power of the full.  I loaded all my speakers with 15" Dayton Pro speakers and use a horn for the upper ranges.

Just an FYI if it helps you out.  Good luck and enjoy your imperials, whichever configuration you build!

Jim P