Eames Quadreflex

[jlsem]

Anybody with any info on these? I'm particularly interested in a plan or scale drawing.

http://www.hifilit.com/hifilit/Stephens/quadreflexA1.jpg

Thanks,
John

 

[Pano]

Wow, cool. 😎 Had no idea that Eames had done speakes.
Looks like a sort of back loaded horn - on a chair base. My wife would love those.

 

[jlsem]

So does mine. That's why it's important for me try and build some. 🙂 I already have the Tru-Sonic 206 AXA drivers.

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

John

 

[Pallas]

It's very nice-looking (I'm a midcentury modernism fan) but as a practical matter it also looks like that cabinet will have lots of diffraction issues due to the sharp edges so close to the coax.

 

[Pano]

Nice looking drivers.

12 or 15 inch?

 

[jlsem]

They are 15" with a compression driver in the middle with a 1" throat. The link in the first post shows the 12" version. I'm looking for pictures of the larger version.

John

 

[Empee]

old thread, old speakers, retro = hip !

Hi There !


I'd like to dig up this old thread, as I got permission to build a pair for our living room (waf 😉 )

Is there anyone who knows more of these cabs ?
maybe drawings or detailed pictures ?

Or would it be best to design something new that would look like the outer form ?


Cheers,

Empee

 

[picowallspeaker]

Modern designs take into account all the errors made in the past .
I see now the drivers are better off the median axis of the cabinets , as a non centered-in-the-very-middle of the baffle gives an opportunity to early reflections from the baffle to be spread not uniformly due to the varying distance of the driver from the boards .
Also ,in that design which may remind a sort of 'Onken' for the bass load , the baffle is quite un-existent ...😱

 

[Empee]

Hi Pico,


Thanks for your comment!

I fully agree about the errors of the past.
Still, there are numerous speakerbuilders who still use centrered speakers and
razorsharp cabinet edges

And really, even with these shortcommings, some speakers really sound very, very good.


But the question about the Quadraflex remains:

is it a bass reflex ?
is it a horn ?
is it some sort of aperiodic box ?
or maybe even a closed box inside a nice looking shell ?


Who is to enter a museum armed with some screwdrivers and measuring tape ? 😀



Empee

 

[picowallspeaker]

For me the major issue of that design is at a pure physical matter< the driver has an halo of emission around that somehow interferes with the quasi-😕 spherical point source represented by the woofer> and may end in confused sound....what about central speaker of an LCR system ? 😀

 

[d to the g]

The design of the "horn" looks an awful lot like a Frazier Dixielander.

Another possibility would be to just use the bentwood styling and build something like the Danley SH100. I believe Mr. Danley has been so kind as to say what driver he uses on the HiEff forum.

 

[Empee]

Goodmorning !


Wow,
The Frazier look like a good starting point !

Just add a front facing driver to make the whole fullrange ?


Hey; I just described the RCA twinpower.....
😀

 

[jamikl]

These Eames enclosures look to me to be a big vent reflex with the vent/horn
on all four sides of the driver instead of above and below as done by scottmoose
and Planet 10. I guess that the speaker mounting baffle should have rounded or
tapered edges and I'm sure you could model it as a big vent in Horn Response.

On a smaller scale it might be an answer to my own question in the full range
thread.
jamikl

 

[Empee]

Hi Jamikl

Yes,
I was thinking Big Vent Reflex aswell, thinking it would me easiest to calculate.

But speaking of wich;
isn't an Onken basically a Big Vent Reflex ?

another option;
an aperiodic cabinet inside an outer-shell wich is there just for looks ?

 

[GM]

For me the major issue of that design is at a pure physical matter< the driver has an halo of emission around that somehow interferes with the quasi-😕 spherical point source represented by the woofer> and may end in confused sound....

Well, when the driver's acoustic radiating plane is recessed somewhat relative to the vent's, it imparts a mild BP loading that if properly designed will act as an acoustic XO between the front, rear radiation to minimize comb filtering. This does require a stepped up HF response to keep it nominally flat out to a high system cut-off though.

GM

 

[GM]

But speaking of wich;
isn't an Onken basically a Big Vent Reflex ?

another option;
an aperiodic cabinet inside an outer-shell wich is there just for looks ?

Sure, with the right driver specs.

Right, I coined the BVR phrase to describe a large expanding vent system such as the Quadraflex's, so it would apply to the Onken also, though not the RCA which is a folded up front and back loaded horn. Indeed, the Jensen Ultraflex/Onken were based on Thuras's original BVR patent test boxes.

There's been much mystique/misunderstanding about these cabs, but in an interview decades later, Thuras said that he only made such a large cab with a Sd = Av vent system to keep the patent's math simple. The sample driver was actually put in production in a much smaller ~8 ft^3 cab tuned with a Av = 1/4 Sd reflex vent to tune it to Fs.

GM