Jordan JX92 w/ BG NEO 3?

[flatwallet]

Hi, I've lurked this and other forums since buying a pair of Jordans, and I've read allot of posts about GM's aurum bookshelf.

I have a pair of Bohlender Graebner NEO 3 ribbons that I have never done anything with. I also have a pair of Mundorf Supreme caps (3.9mh). I think those would cross the 4ohm BG at around 6800hz? (I'm noob as it gets).

I wonder if these two drivers will work together in a .38cu ft box. I cheesed out and got a p-e curved wall. .

My question is: does anyone else think this would work - just letting the 92's go up and x/o 1st order with the cap up high (like 7kH)?

Another question is this: I thought I'd do a 3db BSC circuit, since they would be close to the wall in a small room. I think I ordered a .6 Janzen inductor and a 2.2ohm resistor.

Am I on the right road at least with this so far? I'd also like to thank the people here for all the thought that goes into these forums. If there are more lurkers out there, and I would say there are allot, then I can firsthand report that much is gained from these forums and the knowledge dispensed here is of great help to noobs - and I thank you for it.

Patrick

[PJN]

First I think crossing first order at 6800 HZ wouldn't be a good idea, the jordans really don't need help until much higher up, say ~ 13 - 14 KHz. Secondly I think that you'll need a bigger inductor for the BSC, say ~ 1.5. Take a look on the Jordan site for recommended BSC circuits.

[Doug Kim]

I have no idea about BG NEO, but for Jordan's BSC, I used 1.8mH + 4 ohm for MLTL48 cabinet and the result is great.

[flatwallet]

correction. I meant 3.9 m(f) for the tweeter cap - not mh. sorry.

[flatwallet]

I goofed up again. I know what I did. I remembered the x/o point with a 6 ohm driver for the 3.9 cap. The NEO 3 is 4ohm. therefore it will x/o higher - looks like about 10K. I have some Northcreek D26 that are 6ohm - could use those too. They would x/o around 6.8 I think. The 4ohm NEO 3-PDR would be higher on same cap. 10k I think.

I need to test the jordan. I think it's closer to 5.3 ohms, iirc.

Question: Wouldn't you mock up the jordan with the tweeter of choice with the 3.9mf cap in the circuit to get the total resistance to select the cap value for BSC? I am designing for 3db - not 6db for BSC.

thx for your input.

Patrick

[gmilitano]

This is where I am at with my JX92S

http://diyaudioprojects.blogspot.com...bookshelf.html

more to come as time permits.

6.8k is not a bad choice, but you could run them up higher. These sound fine fullrange on axis. Tweeter is needed off axis.

For the BSC, I settled on 4.5dB, but that will be room / setup dependent.

Keep us posted on your progress.

Cheers

[ttan98]

Jim Griffin uses Jordan JX92S FR in a bookshelf cabinet with a ribbon(Aurum Cantus) similar to yours.

He used x-over at around 3Khz and implemented it very succefully, he has a paper published, try search for this name you can get that paper.

Similarly I use a different full range I also x-over around 3.5Khz quite successfully, sounds good.

[flatwallet]

thank you all for you posts, and I am sorry about my mistakes posting. I can't edit cause of noob status, and I should've used preview.

I have hooked up some 6 ohm NorthCreek D26 tweets and I think it sounds great. I don't have any real experience, tho. I have Mundorf Mcap Supreme 3.9mF value on the tweeters. Mr. Short sent the impedence curves with the tweeters, which appears to be about 7.5ohms at the X/O point. An online X/O calc says that the X/O point should be 6425hz using 7.5ohms as a guestimate for impedence. That is good because I wanted it to come in just below some "stuff" on the JX92's waterfall plot that looks to be in the 7 to 9khz range. I think the tweeter addition sounds very good, but I could hook up another amp and play w/ the DBX active XO to get a better feel for it. I also have 3.3mF Vcap silver/oil on the way which will raise the XO point some more. Also, I'm going to AB the BG NEO 3's with the Northcreek D26's and pick which cap and tweeter gets to go on to the swimsuit competition.

I've ordered some parts for attenuating the tweeters 2db, and BSC (if I use BSC), and did a mockup of the baffle which will replace the 1" MDF with 2" solid cherry. I mean, it's not like we really NEED the extension leaf in the dining table- am I right or am I right?

[GM]

Originally posted by flatwallet
Hi, I've lurked this and other forums since buying a pair of Jordans, and I've read allot of posts about GM's aurum bookshelf.

Greets!

That would be Jim Griffin's most excellent design, I don't do 'bookshelf' speaker designs, though I guess you could fold up some of my smaller tower designs (aka MLTLs) to make large ones.

GM

[flatwallet]

yes, thx for the correction. My senior moment again. I was thinking "jim" and typed "gm". thx for your input as well.

patrick