Mid Bass Horn Design 80-800 Hz

[Steve Mac]

The size of the edgarhorn is smaller which means the box or shell I would stick it in can have the same dimension as the 511 shell...so this hasn't shown up on my radar...yet.

But then...I have not made any chamber yet so?
As far as the edgar versus the altec...I haven't listened enough to have an opinion, but it seems the altec throw wider side to side...which I like. I don't want to have too much of an opinion until I hear a little high end with the edgars...but I was like a high school girl in love with the way the altecs were sounding these past few days. Even set up as they are, the horn in horn presentation is excellent. I can only assume now that because the mid bass horn is so big relative to the mid range horn...that I am getting away with this. And I'm okay with that. I think I got a lot of raw material to play with here...I just need to continue to listen, learn, measure...and drink a little wine now and again. I will say I am impatient to hear a super tweeter with this system. Anyone here got an extra ev t350? I got one...

<font color="#FFFFFF" size="1">[ March 25, 2008 12:23 AM: Message edited by: Steve Mac ]</font>

[Steve Mac]

Oh, one thing I noticed. The rear chamber back panel. Nothing vibrates on the horn when it's running except this back panel...which must be under substantial pressure. It is likely a candidate for another smaller 3/4" panel glued to the outside to further stiffen.

[bfish]

If it's just vibrating in the center, bracing will help. If the whole panel's vibrating, it's doing it because it can, and is "floating" on the gasket.

[bottle-neck]

I can't believe it!... this is exactly what I'm planning too..

2 x horn sub
2 x dual 15's in a front loaded horn ( http://www.voiceofthetheatre.com/815A.th.htm)
2 x Great Plains/Altec compression, horn and driver undecided
2 x JBL 2405 slot tweeter over the top.

I can't believe I've stumbled across a site where 2!! people have done virtually the same thing, with minor differences. What luck!!

When I start my build around May (co-inciding with a house-move), I'll be picking your brains if I may. Most especially I'll need help with crossovers.. :S

[bottle-neck]

Hey bfish,

I noticed on your site (great builds by the way, a real inspiration) - you have a round tractrix in one room, and an edgar in the other.

I'll be going for the 815a style dual 15, as you have with the edgar.

I just wondered if you'd tried both a round horn aswell as the edgar in this role. I'm hoping to learn from your experiences.

Thanks

[BoydB]

Bottle-neck, my horn testing placed more emphasis on how the HF horn performed in various sized rooms opposed to how the horn mated with the bass horn, see my post above. My testing was not conclusive enough to show a definitive winner regarding your query, sorry.

Boyd

[BoydB]

Bottle-neck, curiosity has overcome me. As time allows I'll compare the Edgar horns with the round tractrix on the 815a woofer horns and report back my impressions. How far away is your listening position?

Boyd

[Steve Mac]

My super bad cat...

I've got three Stratos amps on the rig.
The sound of the rig is scaring the heck out of me.
Stratos plus Altec = good

BTW...check out the shelving.
3 tiered adjustable...each shelf can hold 350 pounds. 37 bucks at Lowe's. The engineering of this shelf is unbelievably great. I bought two, added a fourth shelf...it's completely adjustable, completely strong and completely cheap. It's called "real Organized".

[Steve Mac]

Chopped up a couple of bar stools to finally experiment with the horn in horn presentation:
pic 1
pic 2

[Steve Mac]

Got a little work done this weekend.
Early in the project I buried some pilot holes to bolt
the side walls. Up until now there were just a few screws
holding the walls into shape.

So, what I did was to flop the subwoofers so they fold
in and the woofers are now protected inside. Then I placed
a proper plywood platform on the subwoofer. After that I
drilled out the walls and wedges and bolted it up proper.
new orientation:
http://www.superbadcat.com/midBassDe...ics/bolt02.jpg

bolting:
http://www.superbadcat.com/midBassDe...ics/bolt04.jpg
http://www.superbadcat.com/midBassDe...ics/bolt05.jpg

a suitable fit:
http://www.superbadcat.com/midBassDe...ics/bolt07.jpg

toed in:
http://www.superbadcat.com/midBassDe...ics/bolt06.jpg

system back up:
http://www.superbadcat.com/midBassDe...ics/bolt08.jpg

Distance between the inside mid bass horn walls for a screen
is 120 inches. With a border...~5 inches.. that leaves about
a 9 foot wide screen. At a 13 foot viewing distance...
that's a 38 degree viewing angle...for 16:9 ratio that's
under the max recommended THX of 40 degrees. I'm in the game.

Right now I'm listening to "Caravan" by the Dolphins off
their CD Old World/New World. Buy this CD...turn it way up
...it is awesome. I'm not kidding. Dave Brubeck's son Dan
is the drummer and this is his band. His father must be d=a=m proud.
Anyway, your Altecs will wake up and smile under the dynamics.