[versus rider]

As the title, does anyone have dimensions of their H frame for Eminence Alpha that has stood the test of time and gives pleasing bass. I need to reduce the height of my speakers, at present the bass section is about 660mm tall, combined with a 200Hz tractrix horn they are over 1 metre. I know that an H frame will be around 440mm high and so combined with the horn I cannot get shorter than around 1 metre. But I am thinking to site the H frames to the inside of the horns and mount the horns on a stand.

[MJK]

The H frame dimensions and crossover settings given in this article

http://www.quarter-wave.com/OBs/U_and_H_Frames.pdf

have been used my quite a few DIYers and the reports have generally been positive. The design was provided in 2008 so I guess one could say it has stood the test of time.

[versus rider]

The H frame dimensions and crossover settings given in this article

http://www.quarter-wave.com/OBs/U_and_H_Frames.pdf

have been used my quite a few DIYers and the reports have generally been positive. The design was provided in 2008 so I guess one could say it has stood the test of time.

thanks for that, I had seen that article but not read it through. He talks of a cut off at 200Hz and that increase the length of the frame would result in a peaking response around the cut off. It says nothing that I can see about reducing the length, I have calculated the length based on a cut off at 350Hz ( I run my alphas up to 350Hz with the help of frame bracing ) at 226mm long. Would this have some other effect.

[MJK]

Reducing the length allows you to run the H frame higher in frequency but at the cost of some low end extension. The shorter H frame will not go as low in frequency (probably less than 5 Hz difference) and will be a little more efficient. The low end curve of the shorter design will be between the H frame and OB SPL responses in the article. It is all trade-offs.