EPOS 14 Super Size

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Seems a bit bold to claim you've improved the phase alignment of a speaker when you don't have phase measurements of the original...
But we DO have a phase measurement of the original...it's IN PHASE at 3.2kHz crossover. :cool:

The rest is just TECHNIQUE, as they say. Nobel prize winner Dick Feynman, who developed the only theory of the electron that works known as QED, was a great friend of Lenny Susskind, as it happens. Two giants of physics, both having the rare ability to look at complex things in a simple way.

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


Richard Feynman on the Double Slit Paradox: Particle or Wave? - YouTube

Ah, back to subwoofers. :rolleyes:
 
Thanks everyone.

I knew that someone from the US would chime in once I mentioned sub-woofers.

Whew! I'll have no trouble building the subs but I'm not so sure about the electronics.
The subwoofer could be a simple 8" or 10" in a sealed enclosure. I think you're right regarding electronics.

There are two schools when it comes to subwoofer use and implementation:
1) Thoose who just want to add subfrequencys to the main speakers.
2) Thoose who want active crossover, filtering low bass away from main speakers.

I think 1) is most popular in UK. Perhaps because you have things like flat earth, source first and PRAT from the Naim/Linn community. Seems like REL are one of the only subwoofer manufacturer that's approved with their ability to low-pass the sub really low.

Personally I prefer the no. 2) approach - filtering the low frequencies out of the mains, and handing over the sub-duty to eksternal woofers. In order to acheive this, you'll need an active or passive line level crossover in the signal chain - usually between preamp and poweramp.

Both approaches have their own pros and cons.
 
But we DO have a phase measurement of the original...it's IN PHASE at 3.2kHz crossover. :cool:

The rest is just TECHNIQUE, as they say.
Approximately, on some axis. I guess if you were to use response measurements and the inverse of the crossover phase shift to determine the phase tilt inherent to each driver, then use that phase and the driver response to determine the physical offsets relative to the measurement location, then maybe you could simulate a new crossover with phase tracking that is close to reality? I don't see how you could do that with the Stereophile measurements, though (averaged sum measurements).
 
My heart always sinks when I hear people mention Doppler distortion in loudspeakers...:rolleyes:

There is NO SUCH THING! :D

We all know what ambulances sound like when they are approaching or departing, the tone changes, but this has nothing to do with linear systems.

The whole basis of the Fourier Transform is that the sine waves do not interact.

I WOULD buy an explanation that excessive bass takes a loudspeaker outside its linear area and causes INTERMODULATION between frequencies. :cool:

As for more bass from a two-way like the EPOS ES 14, well you really need a three way for a bigger room if you want it to go loud without distortion. That's the simple physics of it!

Doppler exists the question is if it is audible for a given situation. Note the
references from Klipsch and Linkwitz:
Doppler Distortion in loudspeakers
 
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If you really want to build a tower enclosure, why not measure the T&S
parameters of the woofer and find one that is close. Perhaps something
like the Dayton Reference drivers. Then add the second woofer closer to
the floor with a large inductor in series to give it a bit more baffle step
compensation and to reduce the floor bounce null. Is it an 8 ohm system?
It will then be 4 ohm in the bass after the change, can your amp handle it?
 
Another thought, you could test this idea in mono by stacking your 2 speakers and driving the lower woofer (system) through an inductor, with a Zobel on it. Listen in mono and give it time (a few days) so that your ear-brain can re-adjust through FR adaptation.

This leads to the idea, if you like the above arrangement, to just make stand/boxes that are the same size as the originals tuned to the same frequency with a driver that is similar to the original. The divided enclosure avoids introducing new/different box modes.

You now have more driver excursion making it reasonable to shift the box tuning lower, say to 35 Hz or so if you prefer more extension.
 
Approximately, on some axis. I guess if you were to use response measurements and the inverse of the crossover phase shift to determine the phase tilt inherent to each driver, then use that phase and the driver response to determine the physical offsets relative to the measurement location, then maybe you could simulate a new crossover with phase tracking that is close to reality? I don't see how you could do that with the Stereophile measurements, though (averaged sum measurements).

Didn't understand a word of that really. Let's hope Christian Ponder gets simpler instructions from Leslie Frazier next year, because we surely have common ground in loving the VIKINGS. Skal! :)

My approach was a lot simpler. I outline it below in a visual form. 6" bass plus 1" tweeter is fairly standard stuff that works. The phase is not going to be a million miles away, though I'd dump the metal dome. :D

I really like PB2's suggestion of converting it to a 2.5 Way speaker. I'd guess you want to get near closed box on the Epos (Using a foam plug on the reflex) and add a 6" woofer and Zobel on a near 10mH coil, as with the B&W Matrix 3. You should then get some bass and spare the Epos from bass excursion. Wasn't there a Rogers subwoofer for the small but beautifully formed BBC LS3/5A along these lines?
 

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