JX92S Group buy

[billnchristy]

Here is a higly un-scientific room sweep at my listening position.

Ignore anything under 100hz, I have some room noise somewhere.

An externally hosted image should be here but it was not working when we last tested it.

My second sweep with the sub still had a 20k peak, though not as high...seems the midrange measurement was pretty close:

This was with my sub (again the 50hz down stuff is highly suspect)

An externally hosted image should be here but it was not working when we last tested it.

 

[t-head]

audiosteve,

They just get better and better. Mine have in excess of 1000 hrs and they are just fine. Maybe 500 hrs or so...YMMV...keep runnin' 'em...I doubt you will be disappointed, unless you don't like detail, imaging and 'live sound'.

t

 

[billnchristy]

I have always used mine with tubes too, so that might be why I don't think the upper end is sharp.

Might want to play with stuffing levels as well. My enclosure is 7l sealed so it is very similar to yours. I also put some of those felt moving pad on the back wall of the enclosure...not sure if it helped or not...

 

[hifiZen]

audiosteve,

Jim Griffin commented regarding someone else's initial complaints of harshness in another thread, that BSC is definitely needed to remove the harsh and fatiguing sound. Not sure if that's exactly what you're experiencing, but he recommended 1.5mH || 4ohms for the 7.5" baffle width. I vaguely recall there's a table of BSC component values for other baffle widths in that thread.

 

[billnchristy]

Again, YMMV, but I have never used a baffle step either on mine and I routinely listen for 4-6hrs at a time and have never been fatigued.

I am getting really antsy about getting the second pair built...I would really like a second 2ch system downstairs.

 

[Colin]

Does anyone know how long these need to break in? I just put them in an 8 liter sealed box with wool stuffing and am so far thoroughly unimpressed. They sound harsh to my ears. But the imaging is extraordinary and addictive. Does anyone have any experience with break-in or harshness issues? BTW, I am not using any BSC, just straight connect.

Thanks,
Steve

A few comments from my own experience: First, toe them in to the recommended 60 degrees; the axis is designed to cross well in front of the listening position, otherwise you get the designed upper peak head on. Second, if you've access to another amp, try that. I think the peak can make them amp sensitive. Third, depending on cabinet, BSC is worth pursuing.

I imagine Jim's ribbon and crossover addresses all this, at the expense of going against the purist fullrange grain.

There is a list of bsc values on the Jordan site, although they relate to the specific enclosures featured on the page (the list is per volume but I assume it matches the baffle width of the design shown). List here.

 

[folkeb]

I´ve just recieved the speakers yesterday, and they look great. Thanks for the great effort!

I´ll be building a copy of Jim Griffin´s MTML and see how they compare to my current speaker, the dynabel Euforia (www.dynabel.no).

- Folke

 

[audiosteve]

Thanks to all for the good feedback on harshness, break in and BSC. I'll be playing around with that and will see what happens.

 

[planet10]

I got mine in temporary break-in boxes last night (~5-6 litre aperiodic). Sitting on top of the µFonken woofs. Pleansant sounding. I'll report back again when they have a few more hours and i've had more listening & playing time.

dave

 

[BWRX]

Those are some nice "temporary break-in boxes"! Mine are playing music while sitting on folder holders on my desk... I would take a picture but it's a bit shameful to see them like that

 

[Colin]

I got mine in temporary break-in boxes last night (~5-6 litre aperiodic). Sitting on top of the µFonken woofs. Pleansant sounding. I'll report back again when they have a few more hours and i've had more listening & playing time.

dave

An aperiodic enclosure would be appropriate for these as TJ wrote one of the original articles on this type of loading. There's a 4.6Mb PDF here.

 

[DaveM]

That link is not working.

 

[Colin]

You're right - must be out of date. Google might track it down - E. J. Jordan: 'A cabinet of reduced size with better low-frequency performance', pub Wireless World 1956. Planet10 probably already has it ...

 

[t-head]

Google did no better than the dead link above...anybody care to give us a link to this aperiodic box? I was planning on using PE box until I can build something else...suggestions for a nice temp box?

t

 

[Colin]

It was a general article so unless you want it for historical reasons, there is more modern material on the subject out there. There have been a few threads here.

I have a copy of the original if you want to PM me.

 

[planet10]

An aperiodic enclosure would be appropriate for these as TJ wrote one of the original articles on this type of loading. There's a 4.6Mb PDF

That link is not working.

http://p10hifi.net/planet10/TLS/downloads/TedJordanAperiodic.pdf

I am well familiar with that paper (it was i who scanned it and posted it )

Due to lots of traffic i moved all the media on the TL site to my other dotMac space... the above link works.

dave

 

[BWRX]

Everyone has responded to my emails except for 6 delinquents (one is not a member of the forum).

habsrock93 (last seen online 2/21/08)
jerishi (last seen online 12/19/2007!!!)
mojopin (last seen online 11/22/2007!!!)
Sky123 (last seen online 10/19/2007!!!)
eparson (last seen online YESTERDAY)
Roy C.

Please contact me to let me know if you are still interested in a pair of drivers!

Still waiting to hear from any of these people... I will give each of you another week or so after which your drivers will go to those on the waiting list. I've sent multiple emails and am not going to waste my time tracking any of you down more than I already have.

 

[ejfud]

Ah forget them, I want a pair.

 

[BWRX]

I know, I'm just trying to be nice but I do have my limits.

 

[gmilitano]

I am well familiar with that paper (it was i who scanned it and posted it

Nice paper!

Dave, can I add that PDF to my page on Aperiodic Speakers Enclosures?