Omega frame woofer

[Jaco Pastorius]

Trying to avoid “low frequency” T-line resonance in a W-frame dipole woofer I’ve thought about this type of configuration:

An externally hosted image should be here but it was not working when we last tested it.

Obviously overall dimension is not my problem..


I think that the only resonance will be the one between the parallel faces of the “woofer open box” but I also think that it will be a relative high frequency resonance due to the small dimension of the box itself..

 

[Fast1one]

Not sure if that will work the same way...I believe the W frame works by loading the drivers against the opposing walls and each other...

 

[Jaco Pastorius]

I believe the W frame works by loading the drivers against the opposing walls and each other...

Do you mean that could be a difference in the dipole axis pattern?

 

[Rudolf]

Jaco,
the advantage of the lowered fs of a W-frame needs a tight "box" in front and back.
If you open up those "boxes" you will loose bottom frequencies at the same time. I wonder why you don´t change to a H-frame instead.

There is no resonance between the parallel faces of the loudspeaker mounting baffles. The only - and dominant - resonance is the lambda/4 reso of the T-line which is only slightly attenuated by opening up the outer sides.

 

[Fast1one]

Do you mean that could be a difference in the dipole axis pattern?

My understanding is having the walls very close to the woofer lowers the QMS (mechanical due to loading) and lowers the FS...

The results is more power handling form the loading, a lower roll off, but a lower sensitivity as well...

If I remember correctly, it also lowers distortion according to Linkwitz...

 

[Jaco Pastorius]

Hi all

Rudolf you are in right! I’ve expressed myself in a very wrong way (sorry but my English is terrible)

I’ didn’t want to say that the resonance is formed by the parallel faces! I wanted to say that the parallel faces form the t-line that creates resonance..

I now that the addiction of the air mass “trapped” between the tight boxes lowers the fs and so extends frequency response loosing spl but this is not my “goal”

I would like to reach these two features of the w-frame mounting:

1° forces cancellation

2° odd order harmonic distortions reducing by the reverse movement of the motors

and trying to reduce resonance..

I now that I can reach the second point with an h-frame, I’ve built one prototype recently, but I consider vibrations too strong..

Fast1one you are in right too.. I’ve have understand that you were talking about room walls not about cabinet walls..