Swifts and other birds

[phase_accurate]

I just wouldn't like to know how many designs by the members of this forum behave like this !

Regards

Charles

 

[SY]

Charles: No doubt! With the sort of modeling software and measurement capability we have today, there's not much excuse for even us amateurs to not get it right. Too often, we're like those pioneer women in the Western movies who would close their eyes and turn their heads before firing a gun.

 

[phase_accurate]

There's an additional problem: It is very difficult to build a speaker that fulfills all of the following at once (i.e. every attempt will be a compromise):
Transient perfect (the one in question comes closer than >98 % of all speakers, even the most expensive ones), flat amplitude response, low IMD/THD and good dispersion.

It is even harder to achieve this using passive techniques.

Regards

Charles

 

[kelticwizard]

I once wondered if it were possible to make someting like a bandpass consisting of the following:

A closed chamber behind the driver and one with an aperture in front of the driver. So far it is an ordinary 4th order bandpass enclosure. My idea was to achieve a lower resonant frequency determined by the tunnel and the front chamber (so far ordinary as well) and to make the tunnel dimensions in a way that it has it's 1/4 wavelength one octave above the aforementioned Helmholtz resonance (i.e. generating an upper resonance as well).

A) If you have Excel 2000, Unibox, (freeware), has a version that models pipe resonances. Unibox will also work on Excel 97, but that version does not model pipe resonances. The later version that works with Excel 2000 does. Since Unibox also models 4th order bandpass, you should be able to simulate your idea on Unibox if you check the box that asks if you want to model pipe resonances.

B) The program Sound Easy by Bodzio advertises that it can model any enclosure that you can dream up. It is an Australian program with distributors worldwide. It costs US $250. Here is the link with info and distributors:
http://www.interdomain.net.au/~bodzio/

PS: Your enclosure sounds something like a Daline bandpass. Maybe call it a Daypass?

 

[Bricolo]

No magic, no new physics, just good engineering design.

I'd rather say "just good commercial arguments" not even 100% true ones


They claim for perfect square wave response because of the aligned accoustic centers and the 1st order xo, but...

you'll get perfect transient reproduction with aligned ACs and 1st order only in theory. When the drivers are assumed to be at the same point, or at least very close. On theyr design the drivers are far appart