the amalgam

[cajunner]

I'm looking at what appears to be cutting edge, or state of the art diyaudio discussions and I've come up with a speaker design that is an amalgam, hence the title.

what of a speaker like the pluto, a flooder, a cardioid, and a mass loaded, tuned quarter wave could all come together like parts of a pretty flower?

so here's what I'm thinking:

pluto is omni, but not quite flooder due to the perspective of a low playing image making tweeter.

the big deal, with open baffle, versus infinite baffle is the figure eight radiation pattern versus either the box or in-wall.

tuned quarter wave, presents cleaner bass than simple vented, transmission lines are nice.

I'm probably forgetting something like the mass loading, so add that in for enclosure sizing.


let's put it all together!

we'll take a 4 inch tube, 29 inches long, and run it into a 5.5" tube 4 inches long, only going in 2.5 inches.

the gap between the tubes we fill with carbon, like they use to create the cardioid response in the bigger speakers, there's a company out there... SL links it on his site.

the 4" tube itself has a passive radiator on the other end. this mass loads the quarter wave, causing the reduction in tube length as it affects the wavelength through delay like a port would...

so on the 5" part, there's a nice 5" driver like the pluto. At the other end of the 4" pipe, the passive radiator is 5" also. It's not there as a reflex vent, it's there to tune the quarter wave so the pipe can shorten up and you can put this assembly up in the ceiling.

so we have a flooder from up top, (better in a 10 foot ceiling, probably) that has cardioid response pattern due to the carbon section running on the 5" pipe perimeter, and the 4" pipe serves as an enclosure but also as a tuning aid for the QW resonant structure.

all the other parts of pluto construction still apply, using the Aura Whisper and the 1K cutoff, time alignment, low diffractive elements...

although, you would need to point the Whisper down towards the listening area, at an angle somewhat like the Mirage, I guess, to keep the vertical axis from showing up..


thoughts?

[Francec]

Que?

[graaf]

Originally Posted by cajunner

so here's what I'm thinking:
...
thoughts?

some picture/scheme posted is needed

[Tytte71]

Please make a scetch or something

[graaf]

Originally Posted by Tytte71

Please make a scetch or something

yeah a visualisation is needed

[cajunner]

sorry guys, I have computer literacy issues.

it's really a mash-up of all the things that seem to be hot in the speaker design circles of late.

have no idea if it's worth a try!



anyways, I find the cardioid response pattern from a single driver using the engineered delay of acoustic filtering using carbon media to be very interesting.

I figured why not be able to do this with the Pluto, considering how a flooder puts too much of the reflected energy in the front of the listening area into play, if it's highly reflective, and people moan at the ceiling reflection quandary of having your midrange aimed directly upward to a flat, uncooperative reflector..

so I thought, reverse it!

fire the mids downward, where there is stuff to break up the reflection and there are floor treatments like carpeting, that don't look out of place in the room...

so you get flooder ambience, but less room interaction.

with an optimized geometry in the design of the cardioid delay-inducing stuffing/vent, surrounding the smaller pipe of the quarter-wave tube, you'd have a compromise in the response pattern but possibly with the lower reflection of the cardioid polar response, coming from around the back of the upside-down Pluto, you'd regain some output through the forward energy redoubled by the rear-wave acoustic make-up as it affects the omni-sphere of radiation.

lower reflections from the front of the listening area, increased output (slight) from cardioid response pattern, and yet, more than enough reflections to create a believable auditory scene.

I believe that all of the work done in the 1000 hz and below is sufficient to create the transfer of flooder to more directivity-related phenomena, and ease the burden for some that the omni leads the listener into too large a stage, reducing the movie screen size of the stage with it's lack of "blackness" between instruments that omni produces to something managed and perhaps, not connected.

the air, between, haha...