High Efficiency Speaker Asylum

Need speakers that can rock with just one watt? You found da place.

Return to High Efficiency Speaker Asylum

Message Sort: Post Order or Asylum Reverse Threaded

A question for the horn fundis

196.34.250.5
Posted on April 27, 2000 at 21:30:21
Deon C


 
Hi to all fellow inmates
I have a question about the rear loading of horn drivers. I've had this question for a while, but it has been brought to the fore again when looking at these photos of Miroslav Ivanek's DIY Hedlunds. It is this- what if the loading cavity behind the driver was large, before the horn starts. In the first picture I have indicated which part needs to be closed on the Hedlunds.

I have added the next two pictures just to give some clarity as to which area must be closed on the Hedlunds.



This is just an example. My question is what effect this would have, either on the Hedlund or any other horn desing is the driver saw a 'largish' cavity behind it before venting into the horn itself. Will this not allow lower bass, as well as allow less midrange to 'escape' into the horn. Opinions, ideas, anyone to try this?
Enjoy.
Deon

 

Hide full thread outline!
    ...
Re: Nothing to do with your question, posted on April 28, 2000 at 10:55:30
Steve


 
But don't horn loudspeakers generate some absolutely gorgeous woodwork?

 

You BETCHA !! Stunning !! :-) (nt), posted on April 28, 2000 at 16:10:53
Deon C


 
nt = no text

 

Re: A question for the horn fundis, posted on April 28, 2000 at 16:43:16
JRutter


 
From the All Fun Horn page:

A larger cavity between the driver and the throat of the horn lowers the upper cutoff frequency of the bandwidth feeding the horn:

Upper cut-off frequency = c * At / (2 * p * V)

Where:

V = Volume of cavity

At = area of port, i.e. horn throat area

c = Speed of sound

So increasing the volume behind the driver means less midrange into the horn.

-John

 

That's what I thought, posted on April 28, 2000 at 16:58:15
Deon C


 
By doing this then, one should be able to better control the bass response, and at the same time remove some mids from the horn which can induce muddle, not so? I would think this is something for someone thinking of building a horn like the Hedlund, one that allows such a change, to experiment with, or what do you think?
Enjoy.
Deon

 

Re: That's what I thought, posted on April 30, 2000 at 20:01:26
GM


 
Think of a back loaded horn as ~ a horn loaded reflex port, so the larger the net volume of the back box, the lower it's Qtb. While it does lower the upper BW, it also increases the lower BW, at the expense of a higher F3 and lower power handling capability.

Not an acceptable tradeoff IMO, especially with the typical full range driver's limited Xmax.

 

HELP, HELP, PLEASE., posted on May 2, 2000 at 13:45:51
Michaelz


 
Would someone dissertate on the relationship(s) between cavity (or air chamber), length, throat area, mouth size of back-loaded horn?
I mean, how do these variables interact in practice?

Thanks,

Michael

 

Re: HELP, HELP, PLEASE., posted on May 2, 2000 at 22:02:17
GM


 
With much complexity. Change one, and it impacts all the others. What you're asking for is a good sized book to adequately cover it all. :^))

Study Thiele/Small for vented box theory, then Marshal Leach's AES "Loudspeaker Anthology #2, "On the specification of moving coil drivers for low frequency horn loaded loudspeakers".

Once you've digested these, whatever specific questions, if any, you may still have can more easily be addressed.

 

Re: HELP, HELP, PLEASE., posted on May 3, 2000 at 05:17:51
Michaelz


 
Hello, GM:

As always thanks for the lead. That was very good direction not only for me but for all who want to build their own horn.

Michael

 

Page processed in 0.022 seconds.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]