Pluto clone ... revisited

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Now that SL published 2.1 iteration of his pluto, it's time for me to revisit my clone. They are basically is the same design and measurements, only that they use local DSE woofers. Both old Peerless and Seas LR is unobtanioum down under as they are expensive to import.

Upon impedance measurement I found out it may able to to be equalise down 20Hz using linkwitz biquad. WHich is ridiculous for a 5.5" woofer. Won't count on the SPL level though... :D

Also, added the 220Hz notch of Pluto 2.1

plutoImp.jpg


Q before biquad circuit is 3.0, which becomes a nice 0.8 at 20Hz. I've bought all the components and we will have blastoff in few hours :smash:

pluto2.jpg
 
After a more proper biquad equalization it's much much better.

pluto075.jpg



It's flat to 20Hz with Q of 0.75, a real punishment to the driver at low frequency. Testing the system using sine tones, 30Hz is still ok but 20Hz gives buzzing noise. Not noticable with music.

pluto075_fr.jpg


I sat down to my normal listening position in quite a large room. Very nice, very deep. I have a pair of 15" woofers which I had to check it's turned off! Some materials I could not play at normal level due to extreme excursion such as "cousin john" (Marcus Miller).

Mid-high are glorious. Very realistc, detailed, and natural. I think the texture and notes are better than my dipoles. The imaging is different than OB. I think it's more "round" rather than deep dipole imaging. I like it better somewhat.

After a while listening, I noticed the bass is uneven and was ready to do other measurement and changes when I remembered about room nodes. Sure enough walking around the room I can easily distinguish them. I've lived with dipoles for so long that I forgotten this problem with sealed woofer.

Sure enough after identifying this I could not listen to it :xeye: . Every song, every acoustic bass I was thinking of it and identified it readily. I hate this boomy thing !

So back to the storage for now. The omni design revolutionary, but sealed woofers is not the way to go, I think ....
 
"local DSE woofers"

Are you sure those are DSE ? Can't find any speaker drivers on DSE site anymore ... perhaps Jaycar ? Can you post a link ?
I wouldn't mind making Pluto 2.1 'clones' as an experiment into omnipoles. Except I'd probably equalize them to 40Hz 'only', I think 24dB boost is a bit too much for a 5" ...

Thanks,
Bratislav
 
Although I haven't heard the SL Pluto, I don't see how you can take a single 5 inch driver down into the bass region, especially when the listener is going to be way off axis relative to the direction the 5 inch is aimed. Sure bass diffracts, but still. For low listening levels maybe they are pretty darn good. Another issue is that OB dipole speakers and Omnidirectional speakers such as the Plutos need to be at least 3 ft. away from any walls or there are bad psycho-acoustic effects. I've been studying this for many years. I've been living with my own brew of OB speakers for a few years, and although I'm very pleased with them in general, I suspect that floor to ceiling vertical line array woofers would work better with the acoustics of a typical listening room, thereby virtually eliminating boominess anywhere in the room. See my OB's at Bob's Website . click on Audio, then on Aurium Waveguide. Having woofs go flat to 25HZ is definitely worth it in my opinion, but you've got to have the ability to move a lot of air, AND deal with room acoustics well. That's easier said than done in most rooms.
 
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