dipole drivers

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JeffB

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Re: dipole drivers
« Reply #20 on: 8 Nov 2012, 01:06 am »
All speaker designs are a trade-off.
Some advantages of open-baffle:
Equal air pressure on both sides of the cone results in more accurate cone movement.
No sound reflecting off the inside of a cabinet and then back through the cone.
No cabinet vibrations.
A radiation pattern into the room that has less pronounced room modes and better power response.

Disadvantages:
6db per octave roll-off starting at the dipole peak.
frequency response not as flat.
wider baffles are required, which may be unattractive to some people or don't fit well in the desired room.
may require more drivers and/or bigger drivers.


The sound is different than the conventional box speaker, which to some sounds better and to others just seems different and therefore wrong.

studiotech

Re: dipole drivers
« Reply #21 on: 8 Nov 2012, 02:56 am »
Err... just so we're clear on the definition, what you are describing is not a monopole. (?)

http://www.linkwitzlab.com/rooms.htm#B

In that graphic, it clearly shows 50Hz as being omnidirectional, 500Hz as a narrowing of the pattern to much less rearward raditation and finally 5KHz as very directional.  Just as I stated...  Not sure where we are disconnecting here.  This is standard behavior of a monopole source, such as a traditional boxed loudspeaker.  I believe that above, you stated these effects backwards, such that the lows are more directional than the highs.

Please note that Sigfried's top diagram is for an "ideal" monopole which is infinitely small AND radiates as a sphere.  This is certainly not the case for a traditional boxed(monopole) loudspeaker, as shown in his diagram directly below the ideal monopole.

Greg

JohnR

Re: dipole drivers
« Reply #22 on: 8 Nov 2012, 05:22 am »
In that graphic, it clearly shows 50Hz as being omnidirectional, 500Hz as a narrowing of the pattern to much less rearward raditation and finally 5KHz as very directional.  Just as I stated...  Not sure where we are disconnecting here.  This is standard behavior of a monopole source, such as a traditional boxed loudspeaker.  I believe that above, you stated these effects backwards, such that the lows are more directional than the highs.

Please note that Sigfried's top diagram is for an "ideal" monopole which is infinitely small AND radiates as a sphere.  This is certainly not the case for a traditional boxed(monopole) loudspeaker, as shown in his diagram directly below the ideal monopole.

Hi Greg, I've highlighted the disconnect in bold. I wouldn't consider a traditional boxed speaker to be a monopole - except at low frequencies where it behaves like one. I didn't state it backwards, that's exactly what I said before: "Conventional boxed speakers (drivers on the front) are not monopoles, except at low frequencies." Over the full range, it isn't designed to behave like a monopole, so why insist on referring to it as a "monopole speaker" ...?

versus rider

Re: dipole drivers
« Reply #23 on: 8 Nov 2012, 08:44 am »
I don't have a DEQX but I've watched two people use and demonstrate them... and all of the processing done by the DEQX is done by taking measurements, isn't it?

Well, as just pointed out, you have one, more or less. So why did you do that?

;)
Yes the DEQX does the measuring but I don't see the results in a graph like you can with whatever software you use. I just let the DEQX do its stuff. I think I have onyl scratched the surface so far with it but hope to have more time to play when my listening room is finished.

studiotech

Re: dipole drivers
« Reply #24 on: 8 Nov 2012, 10:54 pm »
Hi Greg, I've highlighted the disconnect in bold. I wouldn't consider a traditional boxed speaker to be a monopole - except at low frequencies where it behaves like one. I didn't state it backwards, that's exactly what I said before: "Conventional boxed speakers (drivers on the front) are not monopoles, except at low frequencies." Over the full range, it isn't designed to behave like a monopole, so why insist on referring to it as a "monopole speaker" ...?

Yes, I see my mistake from an earlier post.  Poor reading comprehension on my part...my bad.  Please resume normally scheduled programming.   :duh:

Greg