Lambda 15" Dipole up to 1100Hz

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Hi,

is it a good idea to use the Lambda dipole driver as midrange and crossing at 1100 Hz to the Seas H1212?

First sound impression is quite good, not that much difference to the 3-way setup. but as I haven't good measurement equipment, I cannot get the details (distortion figures etc.).

Any comments on such a setup?

Thanks
Stephan
 
i have been asking the same question all over the place since 1 year now :p

everybody will probably tell you that it is not a good idea,
and that the 15" drivers is not able to accuratly deliver quality sound at that speed of movement ..

i'd personally say that 1100hz is quite high,
but most pro manufacturers rate their 15" up to 2Khz

so i don't see why you couldn't use it as u wish!!!

if you like the sound, just keep it as is!!!

Sure feels weird thought to make a big mass like that move at 1000 times per second and more !!!
 
Here is some off-axis plots of a td15x prototype. The 3 traces are on axis, 30 degrees and 45 degrees. That is with the driver mounted in a 17" wide cabinet. It doesn't exactly beam like a normal 15, but it does beam. It looks like 1100 might be OK.
 

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JohnL said:
Here is some off-axis plots of a td15x prototype. The 3 traces are on axis, 30 degrees and 45 degrees. That is with the driver mounted in a 17" wide cabinet. It doesn't exactly beam like a normal 15, but it does beam. It looks like 1100 might be OK.


Thanks for the diagram, is looks ok, up to 1kHz.

I checked non-linear distortion with a 800 Hz sine wave. Looked also ok, -60dB, but done with a very simple setup.

Has anyone an idea what linear distortion might look like?

Stephan
 
AJinFLA said:
Reins,

if you are going to use those drivers and xo, I would strongly suggest using a waveguide to load the tweeter and reduce directivity (and distortion at 1k). The SEAS is very robust, but thats really pushing it. I'm sure you don't have a 15" Lambda to listen at very low volumes ;).
Hifitalo http://www.hifitalo.fi/ sells one made for the H1212. Good luck.

Cheers,

AJ


I tested it, it works very very well. Best is the imaging of the setup. I think the waveguide is a good idea independent if I go 2-way or 3-way.

Thanks
Stephan
 

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I'm using active XO.
2-way: 900Hz 4th order and wave-guide for the tweeter
3-way: at the moment 220Hz 2nd order and 1100Hz 4th order. I tried also 160Hz 4th order and different tweeter XO points. But that upper delivers the most consitent results.

In both cases same filtering and equalizing to smooth the response. But I do that with in room measurements, so the results are not universally valid.

Stephan
 
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