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The Kairos thread

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The Kairos thread

Post Fri Mar 08, 2013 6:51 pm

Meniscus has posted the Kairos loudspeaker kit for purchase that I designed.
Image

To accompany the kit I have created a pdf write-up on the Kairos complete with graphs covering pretty much anything you would want to see and a fuil explanation of the design.

Rather than recreate all of that in this post, I will instead give you a link to download the 23 page pdf file here: https://www.box.com/shared/md4aaedah6batv2ux5ip

Image

Since this is a Meniscus kit, I will use this thread for all discussion and questions regarding the Kairos loudspeaker.

Jeff
Jeff's Excel Loudspeaker Design Software
http://audio.claub.net/software/jbabgy/jbagby.html
Jeff B.
 
Posts: 53
Location: Kokomo, Indiana

Re: The Kairos thread

Post Fri Mar 08, 2013 7:20 pm

Great writeup Jeff, and could be used as an intermediate primer on design work. Advanced concepts without the advanced mathematics that tend to clutter some of the higher end writeups out there. Well done, sir - hope to see them this April!
johnnyrichards
 
Posts: 47

Re: The Kairos thread

Post Fri Mar 08, 2013 9:03 pm

johnnyrichards wrote:
Great writeup Jeff, and could be used as an intermediate primer on design work. Advanced concepts without the advanced mathematics that tend to clutter some of the higher end writeups out there. Well done, sir - hope to see them this April!


Yes, I will bring them to Fort Wayne. Looking forward to meeting you there.
Jeff
Jeff's Excel Loudspeaker Design Software
http://audio.claub.net/software/jbabgy/jbagby.html
Jeff B.
 
Posts: 53
Location: Kokomo, Indiana

Re: The Kairos thread

Post Wed Mar 20, 2013 6:00 am

Hello Sir,
I've been searching around for the best 20L bookshelf kit i could buy for less than 1K$ and i think you realised a great work.
But infortunatly, i have the worst WAF of the world.
I will have to sell my project to my wife like if i would buy an house. I will have to build regular white glossy boxes...
So i would ask you a question : if i buy the kit on meniscus it is possible to modify the cossover for a "time coherent crossover" instead of building the slant-back design ?
Thank you
FLOW
 
Posts: 5

Re: The Kairos thread

Post Wed Mar 20, 2013 1:21 pm

I don't think Jeff plans on redesigning such a project. Changing the baffle angle requires a full redesign.

Later,
Wolf
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Wolf
 
Posts: 58
Location: Indiana

Re: The Kairos thread

Post Wed Mar 20, 2013 2:11 pm

Wolf wrote:
I don't think Jeff plans on redesigning such a project. Changing the baffle angle requires a full redesign.

Later,
Wolf

Well, based on the amount of email and personal messages I am receiving asking for a flat baffle version, it appears there is considerable interest in it. So, I won't call it a redesign, but it will certainly be a new design. And it looks like I will start working on one.

Jeff
Jeff's Excel Loudspeaker Design Software
http://audio.claub.net/software/jbabgy/jbagby.html
Jeff B.
 
Posts: 53
Location: Kokomo, Indiana

Re: The Kairos thread

Post Thu Mar 21, 2013 1:47 am

Correction noted!

I will also say that the cabinet from Meniscus is not in my taste for looks and finish of the original Kairos. It just looks odd to me.
But then again- my designs look odd to other people,
Wolf
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Wolf
 
Posts: 58
Location: Indiana

Re: The Kairos thread

Post Fri Mar 22, 2013 8:11 pm

Congrats on the new speaker Jeff. I like the slanted baffle. If it sounds good enough to deserve paint then my wife will think it looks better than any I have built previously. ;)

Can you explain why there is ~1" space between tweeter and woofer? I thought that closer was better.

Is your active 50Hz highpass a 2nd order? With subs can Kairos play loud symphonies and rock, or should highpass be even higher for loud music? Any possibility of a 3 way in the future?
Thanks
Rich
richidoo
 
Posts: 14

Re: The Kairos thread

Post Sat Mar 23, 2013 9:34 am

richidoo wrote:
Congrats on the new speaker Jeff. I like the slanted baffle. If it sounds good enough to deserve paint then my wife will think it looks better than any I have built previously. ;)

Can you explain why there is ~1" space between tweeter and woofer? I thought that closer was better.

Is your active 50Hz highpass a 2nd order? With subs can Kairos play loud symphonies and rock, or should highpass be even higher for loud music? Any possibility of a 3 way in the future?
Thanks
Rich


The 1" space is a compromise. I needed to achieve the proper offset, but didn't want to have a cabinet angle exceeding 15 degrees. If I spaced the centers fo the two drivers 6" apart (152mm) then I could achieve the proper offset with a 14 degree slant in the baffle.

The rule of thumb about keeping two drivers as close a possible is intended to reduce lobing issues. However, spacing also depends on the crossover frequency, and with the crossover point of about 1.9kHz for this speaker the extra space does not cause any real issues. The drivers are still within one wavelength of the crossover frequency and lobing is well-behaved.

In my active system the highpass is 4th order, but I also drive the speaker full-range too without any issue. With the low tuning frequency I would not push the vented version real hard driving it full-range. You can observe quite a bit of cone motion when it is vented. When I plug the port, which is my preferred way to listen to the speaker I can push it pretty hard without seeing / hearing any problems arise. Of course, this is still only a 6.5" driver and it will only move so much air, so it is limited where high SPL's are concerned. The speaker can still play pretty loud in my family room, but I don't know if my "loud" and your loud are the same thing. If you have a subwoofer and use a highpass filters, and plug the port, then you could easily drive it over 100 dB in room, which for most people is pretty loud.

I have not worked on a three-way version, and I don't have any plans at this time, but I won't say it isn't possilbe.

Jeff
Jeff's Excel Loudspeaker Design Software
http://audio.claub.net/software/jbabgy/jbagby.html
Jeff B.
 
Posts: 53
Location: Kokomo, Indiana

Re: The Kairos thread

Post Sat Mar 23, 2013 3:22 pm

100dB is loud enough for sure. Thanks for all the info Jeff. Kairos is on my to-do list.
Rich
richidoo
 
Posts: 14