Horn size and dispersion characteristics

[Audiodidakt]

Hi

In the attachment I have drawn two different horn-profiles, but where profile is identical for both "inside the box".

The left side horn is quite similar to the Beyma TPL150H-horn profile; i.e. it consist of a throat terminating to a conical/straight CD midarea, and a roundover mouth terminating to the baffelside.

The right side horn is identical save for a much larger mouth.

If I e.g. choose 2000 Hz for XO HP, which is above the horn cut-off for both horns;
will the dispersion charachteristics be similar for the two, or will the SQ be degraded for the larger horn? (because of HOM, more beaming etc?)

The reason for my question is that I am evaluating a speaker design where other aspects of the speaker would take advantake of the bigger horn, but I am uncertain whether this horn profile is suitable in the tweeter frequence area:

http://www.georg-stracke.eu/wp-content/uploads/2011/08/DSC0015-1.jpg

Best regards

Gisle

 

[gedlee]

The mouth diameter determines the lowest frequency of pattern control. At HFs both of those devices will work the same. At the lower cutoff the bigger one will hold the pattern better. Both will have the same HOMs. The larger mouth will also have less mouth diffraction.

 

[Audiodidakt]

Thank you very much Geddes