Michael's comments on flying speakers/drivers are spot on!
BTW, I once tried a completely baffleless dipole bass/sub, using one rubberstring-suspended 18" in the near field (about 70cm from behind). The best and cleanest bass I've ever heard, zero stored energy, perfect mechanical decoupling.
- Klaus
BTW, I once tried a completely baffleless dipole bass/sub, using one rubberstring-suspended 18" in the near field (about 70cm from behind). The best and cleanest bass I've ever heard, zero stored energy, perfect mechanical decoupling.
- Klaus
skorpion said:
Looks like somebody over in the commercial sector has been reading this thread - note this quote from the Audiogon advertisement:
Wonder where they could have gotten the idea to audition the 12NDA520, Alnico Tone Tubby, Altec 414, and EV SRO?
Better they pay the $25,000 to exhibit at the the CES than me.
Talking about the rising response, I found almost all of the 18sound's midranges, midbass, woofers are like this -- severely drop off from 500Hz and down. According to such FR graghs, their sound should be very lean and bass shy.
How do they sound in reality? I doubt the 100~200Hz range with 'only' about 90db/w is adequate for pro sound.
How do they sound in reality? I doubt the 100~200Hz range with 'only' about 90db/w is adequate for pro sound.
More should use MJK's excellent software to simulate loudspeaker response with good resemblance of real life performance.
12NDA520 on the Audiogon baffle would perform like this without any crossovers applied: (courtesy MJK)
18sound take very special response curves in their presentation evidently promoting special, rather small, enclosure sizes.
The issue is more about 12NDA520's cone breakup performance.
/Erling
12NDA520 on the Audiogon baffle would perform like this without any crossovers applied: (courtesy MJK)
An externally hosted image should be here but it was not working when we last tested it.
18sound take very special response curves in their presentation evidently promoting special, rather small, enclosure sizes.
The issue is more about 12NDA520's cone breakup performance.
/Erling
K&Q Sound Genesis LLC & Top Dog
This is great news! You just copy the efficiency figures of off the woofer data sheets and that`s it, your dipole is covering 36 to 20000 Hz (98 db, efficient as hell!) with ease! Now, Top Dog is a much better loudspeaker overall IMHO, it reproduces 35 to 21000 Hz and has above all +100dB efficiency!!! Pure enlightenment!!!!!
Once I built a passive dipole (baffle width cca 50 cm) loudspeaker consisting of two Peerless SLS 12 units per channel, with a measured response down to 30 Hz in my room. It was a 3way with a ribbon tweeter (95 db eff) which had to be padded down about 15 dB! So I guess their efficiency was about 80 db and correspondingly needed quite a lot of "juice" from the partnering amp. It sounded great in the bass though. Years ago tried one Beyma SM 118 (18 inch) in a similar arrangement, needed lots of power too, but I guess it`s just me,
all other dipoles seem to be extraordinarily efficient.
This is great news! You just copy the efficiency figures of off the woofer data sheets and that`s it, your dipole is covering 36 to 20000 Hz (98 db, efficient as hell!) with ease! Now, Top Dog is a much better loudspeaker overall IMHO, it reproduces 35 to 21000 Hz and has above all +100dB efficiency!!! Pure enlightenment!!!!!
Once I built a passive dipole (baffle width cca 50 cm) loudspeaker consisting of two Peerless SLS 12 units per channel, with a measured response down to 30 Hz in my room. It was a 3way with a ribbon tweeter (95 db eff) which had to be padded down about 15 dB! So I guess their efficiency was about 80 db and correspondingly needed quite a lot of "juice" from the partnering amp. It sounded great in the bass though. Years ago tried one Beyma SM 118 (18 inch) in a similar arrangement, needed lots of power too, but I guess it`s just me,
all other dipoles seem to be extraordinarily efficient.
The rising response of the 12NDA520 would be easy to counter with a low value C across the inductor feeding that driver within the crossover; a parallel tuned series loss, with C value between 4.7uF and 22uF.
__________________________________________________
My jigsaw cutting event at the weekend produced this. The crossover component values are not yet tuned to 'voice' the system, but I already have excellent sound.
(Click thumbnail, then click image for larger size.)
The test baffle before this had the fullrange driver at just 40" above floor level - the lowest I have had for decades - mistake - that position did not sound right, and it did not have anything to do with driver interactions. The reason - voices, trumpets etc. just do not sound right when *coming from a seated position* in a room. Now at 54" the sound is most satisfactory. This test piece is just a simple 6ft x 18" Contiboard panel, so I shall be adding another inch of wooden base height, also shallow side and rear frame supports.
Here the Beyma SM115-N and DeltaPro-18A bass drivers complement each other. The 15" provides upper bass attack and definition; the 18" realistic sounding depth and LF ambience. The Beyma does not have the raised peak so many other 15"ers have before roll-off, but does frequency double ( euphonically I persuade myself ! ) on an OB with 20Hz input. The Eminence is relatively dead from about 200Hz upwards which is just like having an extra section of crossover for free. Other Eminence 18"ers are more efficient, but might need more filtering too.
This project is a single amplifier (one ohm capable) design using my transformer based T-bass drive circuit, and is already sounding excellent, with cleaner/deeper bass than gained from any LS used here before - including low ABRs and subs, which as monopoles might might generate an impressively flat SPL response (as for organ music) yet still fail to accurately reproduce the leading edges of LF wavefronts (for drums) as can an OB!
Cheers ....... Graham.
__________________________________________________
My jigsaw cutting event at the weekend produced this. The crossover component values are not yet tuned to 'voice' the system, but I already have excellent sound.
An externally hosted image should be here but it was not working when we last tested it.
(Click thumbnail, then click image for larger size.)
The test baffle before this had the fullrange driver at just 40" above floor level - the lowest I have had for decades - mistake - that position did not sound right, and it did not have anything to do with driver interactions. The reason - voices, trumpets etc. just do not sound right when *coming from a seated position* in a room. Now at 54" the sound is most satisfactory. This test piece is just a simple 6ft x 18" Contiboard panel, so I shall be adding another inch of wooden base height, also shallow side and rear frame supports.
Here the Beyma SM115-N and DeltaPro-18A bass drivers complement each other. The 15" provides upper bass attack and definition; the 18" realistic sounding depth and LF ambience. The Beyma does not have the raised peak so many other 15"ers have before roll-off, but does frequency double ( euphonically I persuade myself ! ) on an OB with 20Hz input. The Eminence is relatively dead from about 200Hz upwards which is just like having an extra section of crossover for free. Other Eminence 18"ers are more efficient, but might need more filtering too.
This project is a single amplifier (one ohm capable) design using my transformer based T-bass drive circuit, and is already sounding excellent, with cleaner/deeper bass than gained from any LS used here before - including low ABRs and subs, which as monopoles might might generate an impressively flat SPL response (as for organ music) yet still fail to accurately reproduce the leading edges of LF wavefronts (for drums) as can an OB!
Cheers ....... Graham.
CLS said:
18 Sound's measurements are done on practical enclosures in a free field (4pi) environment, so the 6dB drop-off below ~ 500Hz is the result of the so-called "baffle step". Other drivers would show a similar drop-off under the same conditions. Some manufacturers provide measurements for "half free field" conditions (2pi), therefore the "baffle step" does not show.
Nice paper by Lansing and Hilliard about the developement of the early Altec systems and the 288 and 515
Rob
http://classicaudio.ru/articles/altec.pdf
Rob
http://classicaudio.ru/articles/altec.pdf
Robh3606 said:Nice paper by Lansing and Hilliard about the developement of the early Altec systems and the 288 and 515
Rob
http://classicaudio.ru/articles/altec.pdf
Rob,
Thank you!
Chris
The Latour isn't the only commercialy viable Field Coil Speaker anymore
http://www.avguide.com/news/2008/09/11/focal-introduces-flagship-grand-utopia-em-speakers/
Focal does it for a lot more $$$.
Chris
http://www.avguide.com/news/2008/09/11/focal-introduces-flagship-grand-utopia-em-speakers/
Focal does it for a lot more $$$.
Chris
Not yet ordered, though I certainly plan to audition them. August and September have turned out to be busy months, with not that much audio content - a lot of other family and house-type events instead.
Martin Seddon of Azurahorn has completed my pair of AH-450's, and has just sent an e-mail asked what diameter I'd like for the casting of the mounting flange - he mentioned 145mm, I need to go downstairs and measure the GPA 288-H's and see how that works out. As I recall, they were bigger than 6" diameter.
Martin Seddon of Azurahorn has completed my pair of AH-450's, and has just sent an e-mail asked what diameter I'd like for the casting of the mounting flange - he mentioned 145mm, I need to go downstairs and measure the GPA 288-H's and see how that works out. As I recall, they were bigger than 6" diameter.
Russell Dawkins said:
I dunno. I don't think anyone can make a value proposition with prices like that. You buy it because you can.
As a sidenote I received my 604 series 3's from GPA and am burning them in slowly in a pair of JE Labs OB's. I will post the results after the xovers and drivers have a few hundred hours as they are a little hard sounding in the upper mids currently.
Chris
Very nice looking concrete horns:
http://www.diyaudio.com/forums/showthread.php?postid=1608243#post1608243
http://www.diyaudio.com/forums/showthread.php?postid=1608243#post1608243