Folded horn - volume between subwoofer cone ane th start of the horn

[benpalmer]

How much of an effect does the volume of air, between the speaker cone, and the mouth of the horn, have on the enclosure? What are the suggested ways to "connect" the loudspeaker to the horn, and how much of an effect does the horn have on the sealed or ported enclosure the subwoofer is in? Thanks.

 

[OscarS]

doesn't change the frequency response too much, its only a couple hundred CCs, depending on the actual cone size.

 

[Zoran]

it could matter, consult articles by Marshall Leach about horns.
then, based on the driver parameters and horn system parameters
You can calculate a proper cavity volume.

 

[benpalmer]

Thanks OscarS and Zoran. If I could get hold of the calculations, do you think a cavity volume could be calculated for two drivers sharing the same cavity for one horn? Is the direction of the horn throat relative to the plane of the loud speaker cones important in anyway or can it be ignored? I'll search for those articles now. Thanks again for your help!

 

[AndrewT]

Consider a compression driver to understand what is happening.

The throat requires all the inputs from the cone to arrive in phase.

This is usually done by ensuring that the travel paths followed along all the alternative routes are very similar in length compared to the wavelength being reproduced.

The same applies when the driver/horn is reproducing longer wavelength signals.

 

[benpalmer]

Hi Andrew, so, for example if I decided to use one horn and two drivers, the cavity should be symmetrical, with the drivers one side of the cavity and the horn throat in the centre of the opposite side, and perhaps angle the drivers so then "aim" at the throat? Cheers. Ben.

 

[Peter M.]

Have you tried Hornresp? Hornresp

 

[AndrewT]

Hi Andrew, so, for example if I decided to use one horn and two drivers, the cavity should be symmetrical, with the drivers one side of the cavity and the horn throat in the centre of the opposite side, and perhaps angle the drivers so then "aim" at the throat? Cheers. Ben.

Now consider a box with a throat at one side (face) and two drivers (5 drivers, one to every face of a cube).

What is the closest distance from any cone to the throat?
What is the longest distance from any cone to the throat?
How do those dimensions compare to the wavelength being reproduced?

There are in addition resonace effects and others. Hornresp should help with these.

 

[pooge]

How much of an effect does the volume of air, between the speaker cone, and the mouth of the horn, have on the enclosure?

From the title of the first post, I believe you meant the volume between the cone and the throat of the horn. This is referred to as the front volume in texts and horn modelling software.

how much of an effect does the horn have on the sealed or ported enclosure the subwoofer is in?

Question isn't clear. Are you referring to the enclosure defining the volume behind the cone in a front loaded horn? If so, a sealed volume behind the cone can be sized to tune the horn by reactance annulling if the horn is a hypex horn.