Front horn loaded bass reflex

[revintage]

Hey,

I have showed a few sims in other threads but I want to dig a little deeper into this.

At the moment I am designing a midbass horn with small dimensions due to lack of free space on the floor. I will have them standing on the floor against sidewall, their footprint being in the ballpark of 50*50cm. I have a pair of 150Hz Lowther-style Tractrix-horns standing in my garage, they are the same type as Bo Hanssons at Opus3:



I have also a few 414-8A in my stash to be mated to the horns and a bassreflex of 40-50dm3. Due to the Altecs qualities we shouldn´t expect to high upper rolloff. Shelving, like in a fullrange "hornreflex", shouldn´t be a problem as the BR only fills in just where the horn starts to fall.

The upper rolloff shouldn´t be a problem when using 2482 in the horns below(note the driver at the bottom), also in the upper right corner you get a glimps of the midhorns:



This is a sim of the horn, box is 40dm3. Note, it will be a big compromise even if the design could be bettered:



My friend Hoktuna has built 816´s and together with 416 he is quite satisfied using them for midbass down to 100Hz. He also uses the same midhorns as I have.

Any thoughts and experiences?

[Fuling]

IIRC those Lowther horns are quite small (and short), I can´t see how they could provide any acoutsic loading down to 150Hz. Well, maybe if placed against wall and floor. Good luck and give it a try, they´re at least heavy enough!

[revintage]

Fuling,
Can´t see any relevance in the comment as we are talking about a hybrid system.

IIRC those Lowther horns are quite small (and short)

Maximum size for a 150Hz horn with 300cm2 At is 4185cm2 Am and 37cm length. Ie very close to this one.

I can´t see how they could provide any acoutsic loading down to 150Hz. Well, maybe if placed against wall and floor.

If you also read my first post again I say:

I will have them standing on the floor against sidewall

About the weight they are just far to heavy. Even you, big fellow, complained when we carried them down to my car.

[Fuling]

Won´t argue with your calculations, my post above was based on gut feelings and (vague) memories.
BTW I´m been thinking about bass reflex midbass horns myself using JBL 2202H to cover ~90-500Hz.

[revintage]

Hey Fuling,
Just for fun I will sim your 2202H.

[Fuling]

Thanks, I´m interested in seeing your results! Not an easy driver to work with, but a few Ohms in series to raise Q seems to help in may cases.

[revintage]

Sorry Fuling,
Couldn´t tame that one. What is it actually for?

[Fuling]

Low mid in some of JBL´s studio monitors, I think. I used them in my old midbass horns 100-600Hz. Quite tricky to get a good balance between horn loading, port frequency and series resistance.

[tinitus]

Originally Posted by revintage

I will have them standing on the floor against sidewall, their footprint being in the ballpark of 50*50cm.

Maximum size for a 150Hz horn with 300cm2 At is 4185cm2 Am and 37cm length.

footprint 50 x 50 ?

means they are taller ?

Im trying to learn a bit of this, out of interest, and due to a project
seems to me a midbass horn gets shorter with bigger throath
Im aiming at 100hz with a 15" woofer, throath 400cm2, mouth 6400cm2(0.64m2), length 0.85m

[revintage]

The 100Hz hornreflex will be ca 70cm tall, having a net volume of 70dm3. A conventional 100Hz Tractrix will have above 200dm3 incl. backchamber.