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Quote from: JoshK on 2 Jan 2009, 02:31 pmThat is going to be a bit difficult to do with hi-eff. Its an outgrowth of Hoffman's iron law that small size (in this case driver size), hi-efficiency and low extention (100hz) can't all be achieved at the same time.Josh, I have to respectfully disagree with your theory. In real life, I'm crossing my Lowther PM2As at 125 and getting mid-bass a plenty. picture: http://www.audiocircle.com/image.php?id=16556 Poll any of the GAS guys that have been by since I finished the OBs and they'll let you know they work. In fact, MeRev (Chris) is building an identical pair he likes the sound so much.Kyrill, if you want real HiE, think about the Lowther PM2A or the PM6A. Not only will you get to 2K, you'll get out to almost 14k. Of all the Lowthers I've listened to over the years, these two models are their best offerings . No 'honk', no 'shout', plenty of detail and extension. When mounted in a baffle like I've constructed and in a room where they can breathe, they throw a monstrous soundstage. Not to mention, you can drive them with any amp you choose to buy from SE 45's on up. Be prepared though, these things aren't cheap nor are they fun to listen to until they get fully broken in (500 hours as a bare minimum and 2K hours they loose the last of their bite).
That is going to be a bit difficult to do with hi-eff. Its an outgrowth of Hoffman's iron law that small size (in this case driver size), hi-efficiency and low extention (100hz) can't all be achieved at the same time.
Cool! Please let us know how you like them.I've used the P.Audio 18" coax and found it very good. A friend has the 12" coax and likes them, too.That 8" driver will be interesting to learn about.
transients really relate to how fast something changes. And that is based on mass. Given a constant force acting on a mass (m1) vs acting on a mass , m2 (and I'll define m2:=1/2m), then the ability to overcome Inertia (not a force) is greatly increase---................t at all. The writer (perhaps) needs to go back to 1st year physics and begin again using proper definitions and nomenclature.
The writer (perhaps) needs to go back to 1st year physics and begin again using proper definitions and nomenclature.
"But i prefer the 8 inch for its weight 17 gram appr. relative to 63 gram of a 12 incher and 160 gram for an 18 incher. SO the servo woofers of 15 inch are heavy and relatively slow, for low bass no bigh deal i want the midrange if possible to be fast and quick with a minimum ( relatively) of overshoot and ringing"Ok, so a little math. for 2 8" drivers: 2X(π X r²) = 2X(4² X π) =32πfor one 10" : π X r² = 5² X π =25πfor one 12" : π X r²= 6² X π =36πfor one 18": π X r²= 9² X π =81πwhat this says is that a pair of 8" drivers will have a larger radiating surface than a single 10, but not quite as much as a single 12". If you mount them in series, you will loose 3dB efficiency, but if they are mounted as close together as possible on the baffle (without touching) then you will get a 3 dB gain. Net gain and loss=0 .However efficiency does not equal sensitivity."Briefly, sensitivity describes how loudly a speaker will play given a certain voltage; efficiency describes how well the loudspeaker converts electrical power into acoustical power. In other words, efficiency is how easy it is or isn't for an amp to develop and maintain that voltage across the speaker, as a load. Sensitivity is measured in decibels relative to a given voltage and measuring distance (typically 2.83V and 1m, respectively), and efficiency can be assessed by looking, not only at sensitivity but also at a speaker's nominal impedance, in ohms. Efficiency can therefore be gleaned from a graph that plots a speaker's impedance, in ohms, vs frequency, in hertz. " ---Art Dudley review of the Horne Shoppe Horn online at Stereophile.comIt has been my personal experience that 2 smaller drivers sound "faster" than one larger one, and mass does have something to do with it---It is a statement of sensitivity, not efficiency. And controlling the smaller mass of 2 8" drivers is easier that controlling the mass of say a single 12 inch driver. Of course this is assuming that the drivers themselves will sound good with an amp with reasonable dampening factor. If the dampening factor is too great , fullrangers can fall on their face, if not enough they can sound sloppy in the bass.
But i prefer the 8 inch for its weight 17 gram appr. relative to 63 gram of a 12 incher and 160 gram for an 18 incher.
