Speaker kit experiments - an archive of the Jäger Speaker development

[kgoss]

I know you guys are covered up with orders from the recent Crack amp sale.  But it's been a month since the last update.  Any news on the speaker front?

Thanks.

 

[Paul Joppa]

From the facebook page:

https://www.facebook.com/photo.php?fbid=10209689504728156&set=a.10207494820222415.1073741828.1046019712&type=3&theater

 

[kgoss]

Thanks Paul.  I didn't even consider looking at Facebook.

 

[Doc B]

We had a great meeting on Saturday, during which all listening was done on the latest iteration of the kit speakers, with the new birch ply cabinets and some adjustments to the crossover to bring the component values a little closer to the design values. We listened with three different amps, three different sources and a pretty broad range of music to try to identify what things we were hearing that were consistent in the character of the speakers with any source or amp.

All in all it was a great session and a really great group of listeners. The birch ply makes for a much more dynamic presentation. My takeaway was that the new crossover components may have filled in a slight depression in the upper end of the woofer's response. With that filled in we now have some leeway to try shading the woofer array which is, essentially, cutting off the upper response of the lower woofer starting at a bit lower point than the upper driver. The theory is that we should get even better imaging (it's already very good) with only one woofer playing the upper mid and lower treble frequencies, along with less of the effects of comb filtering between the two woofers. This would be done without sacrificing any bass.  I'll be ordering parts for the shaded crossover this week.

The other cool news is that the CFO gave me permission to order our new 40W laser cutter today. My hope is to cut 1/8" plywood panels for mounting the crossover components, and to cut and engrave wool felt surrounds for the tweeters.

 

[kgoss]

Thanks for the update Dan. Like everything you guys do I know they won't be released until they perform up to your high standards. So I won't ask when they will be ready for purchase. I really don't need a new pair of speakers, but dang you are making me want to place the order! 

 

[tsingle999]

Can't wait to hear it!

 

[Doc B]

Kelvin built the shaded crossover yesterday and I gave it the first listen at the end of the day. Does some nice things. I'll offer more info after we do some measurements. The other news is that the laser cutter arrived yesterday. I will be setting this up in the shop at home due to its size and venting requirements. Hope to be able to run some trial cuts by next week.

 

[yay]

I assume there will be no way to get this in europe?

 

[Doc B]

We would certainly offer the kit for shipment to Europe. I don't know yet what it would cost.

The shaded crossover has worked out exceptionally well, and I think we are close to locking the design. I am working on the layout of the felt diffraction panels for laser cutting today.

 

[Rocketman248]

Pardon my ignorance.  I know very little of speaker design.  What is a "shaded crossover?"

 

[kgoss]

Doc talks about it in his post on April 3

 

[Rocketman248]

Ah, nice.  I missed that part.  Thanks!

 

[Doc B]

Went a little off the deep end the past couple of days playing with a potentially silly idea for the diffraction felt we will put on either side of the kit speaker tweeters. Have no clue if it will work better, worse, or just the same as a strip of felt or shark's teeth shapes like most everyone else tries. Anyway, I like the look. After 9 hours working out a quadratic residue diffusor cell layout that would fit and function at the frequencies of interest and getting the shapes into the CAD software yesterday, the actual cutting of the pieces took just a few minutes. After a few hours of swearing at the laser cutter software today, that is. At least with my past CNC experience I knew that was coming. Will be comparing these against straight strips of similar felt tomorrow.

 

[debk]

looks cool!
Interested In hearing how it sounds

Debra

 

[Doc B]

Wow, this setup really works! A distinct improvement in image stability over straight strips of the same thickness and type of felt. Sometimes you have to go with your instinct.

 

[johnsonad]

Very cool and much better looking!

 

[Doc B]

Here's the more or less final version of the speaker kit impedance compensation network. Wood board with pressed in solder eyelets is laser cut in house. No solder traces to mess with the sound.

 

[johnsonad]

Nice work!

 

[Rocketman248]

Nice and neat.  Lookin' good!

 

[Hank Murrow]

Dear Paul Joppa;

Could you explain what your "bridged T" network does for the new speaker?

I am sure there are many on our Forum who would be interested in how you developed it. PB says it works a treat!

I hope to hear it myself in late June.

Cheers, Hank in Eugene