Re: holes
Ah, you got a look at the original post!
I haven't done such a modification (rather I've experimented with the design for the midrange with a "fullrange" driver). However I believe Sven was using a Morel unit for his so I can't say IF such a modification is possible with Seas (which is another reason I deleted the post).
Unfortunetly I can no longer find a picture of the rear of Sven's dipole tweeter. I do remember though that the sd of the expansion near the diaprham of the driver was NOT the same sd as the driver itself (probably less than half).
You might try contacting John (Zaph) or MarkK (both are members here) and asking them about the physical possiblity of doing this. At the same time perhaps ask what tweeters they think will likely be best suited to such a modification. In any event I think it's likely you will have some compression.. like you said the sd will not be comparable.
I'm almost tempted to try this myself, but there is a reason (a very related one to this thread) why I wouldn't consider it and instead consider another (though more costly) approach. Hopefully we will get to that, but right now I don't exactly have my hopes up.
Sorry I couldn't be of more help.
inertial said:
Ah, you got a look at the original post!
I haven't done such a modification (rather I've experimented with the design for the midrange with a "fullrange" driver). However I believe Sven was using a Morel unit for his so I can't say IF such a modification is possible with Seas (which is another reason I deleted the post).
Unfortunetly I can no longer find a picture of the rear of Sven's dipole tweeter. I do remember though that the sd of the expansion near the diaprham of the driver was NOT the same sd as the driver itself (probably less than half).
You might try contacting John (Zaph) or MarkK (both are members here) and asking them about the physical possiblity of doing this. At the same time perhaps ask what tweeters they think will likely be best suited to such a modification. In any event I think it's likely you will have some compression.. like you said the sd will not be comparable.
I'm almost tempted to try this myself, but there is a reason (a very related one to this thread) why I wouldn't consider it and instead consider another (though more costly) approach. Hopefully we will get to that, but right now I don't exactly have my hopes up.
Sorry I couldn't be of more help.
ScottG said:
Haven't I said that in every post I've made?
Okay one more try and then I'm really done. It is YOU who is missing the point...... Yes, you can move the omnipoles really close and they will sound good with the penalty of a small sweet spot. But guess what, you can move the dipoles closer too and they will then sound better than the omnipoles because of the 4.8dB thing.
Any place you put them, except by a wall, the dipole will sound better than the omnipole.
Omnipole: farfield = bad, nearfield = good.
Dipole: farfield = good, nearfield = better yet.
Dipole wins both near and far.
mac said:
And doing the same with the dipole would...
True, and it would also provide a smoother bass response (assuming the dipole extended to the bass ala Orion). But the comparison was omni/monopole further in room vs. dipole closer to "normal" placement. Frankly, I think its a good idea in many respects.
There is a downside though (at least with a design similar to the Orion). Moving forward (to the listener) a loudspeaker with that large an sd in the midrange (foreward directed) will cause a loss in subjective focus in the mids at a certain point. To a degree though this is reduced in a design like the Orion because the tweeter operates so low.
Asuming you still have your Orion you might try this out (remember to adjust loudspeaker seperation distance when moving them forward but keep the same "toe-in" angle.. i.e. move the loudspeakers closer together as they get closer to you with out changing their angle).
catapult said:
Haven't I said that in every post I've made?
Yes, you can move the omnipoles really close and they will sound good with the penalty of a small sweet spot. But guess what, you can move the dipoles closer too and they will then sound better than the omnipoles because of the 4.8dB thing.
Any place you put them, except by a wall, the dipole will sound better than the omnipole.
Omnipole: farfield = bad, nearfield = good.
Dipole: farfield = good, nearfield = better yet.
Dipole wins both near and far.
See my last post..
Additionally consider that this makes the asumption that (above the modal region) room effects will be so bad that that you could describe the sound of an monopole farfield as "bad".
In otherwords in my opinion the room's influance above the modal region is not anywhere near as detrimental as what you seem to be describing, and conversly neither is the reduction of those effects - that much better.
The caveat of course is when the wavelength correlates, (or comes close to), with a boundry (particularly a horizontal boundry) as freq.s increase (especially 2k to 9k where we are especially sensetive to changes in freq. response).
Update: My impressions of the Pluto in my living room.
http://www.madisound.com/cgi-bin/discuss.cgi?read=361723
http://www.madisound.com/cgi-bin/discuss.cgi?read=361723
An externally hosted image should be here but it was not working when we last tested it.
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