So, I've built the GM/Abpea "first draft" Jordan JX92s MLTL's. Described right here. They're beautiful. Right now I'm listening to Michael McDonald's "Motown" - I still jump at some of the percussion, it's that good.
But I want to add baffle step compensation, 'cuz Michael's a little weak. OK, I can do inductors & follow formulas, and get about a 2 mH inductor || with a resistor I'll play around with to match the room. But I noticed that Martin King & Bob Brines have included a zobel with their Fostex full-range designs... on the other hand, from what I can find Jim Griffin's Jordan design does not.
Should I include a zobel for the Jordan?
mk
But I want to add baffle step compensation, 'cuz Michael's a little weak. OK, I can do inductors & follow formulas, and get about a 2 mH inductor || with a resistor I'll play around with to match the room. But I noticed that Martin King & Bob Brines have included a zobel with their Fostex full-range designs... on the other hand, from what I can find Jim Griffin's Jordan design does not.
Should I include a zobel for the Jordan?
mk
Interesting! You are the first person I am aware of that has felt it needed some BSC. Anyway, yes, I would try a Zobel. Just using the published specs/plot, I get 5.625 ohms/5.053 uF to reactance annul Re (assumes 4.5 ohms). Really, with a Zobel, you may not feel the need for any BSC.
Anyway, please let us know the results and what you wound up using.
GM
Anyway, please let us know the results and what you wound up using.
GM
Re: What are those RL combinations for?
Yes, though different values may be required for your app.
AFAIK, all the other folks who have built the various ML-TLs are using SS, and while it's possible the receiver is 'laying down' if it's not rated for < a nominal 8 ohm load, I doubt it. Regardless, a Zobel and/or series resistor should remedy the problem.
GM
tcpip said:
Yes, though different values may be required for your app.
Timn8ter said:
AFAIK, all the other folks who have built the various ML-TLs are using SS, and while it's possible the receiver is 'laying down' if it's not rated for < a nominal 8 ohm load, I doubt it. Regardless, a Zobel and/or series resistor should remedy the problem.
GM
Ordinary ported box, a little less than 18" tall on the outside. This is from the Jordan Website. I haven't tried GM's MLTL yet, though he had posted some of those details on this Website in response to one of my questions. GM and 7V had both been very helpful and encouraging. But I've since got caught up in another project.navin said:
Preliminary report on Zobel/BSC - Icky, icky
Preliminary report - I used this Zobel & a parallel 1.2 mH/2.5 ohm resistor for BSC. Yuck! Sounds muddy, boomy, like I put the speakers inside of a cardboard box. High end treble gone? I've gotta get a mic & preamp & start measuring frequency.
FWIW, I also included a driver brace as recommended in the original thread.
Of course, I put the zobel & BSC inside of the box, since I was "finishing" it
. (They now they look great, just sound awful) This weekend I'm going to pull it out, re-stuff, and try the darned thing again, but with just zobel, just BSC (and do them external), just driver brace... the way I should have.
GM said:
Preliminary report - I used this Zobel & a parallel 1.2 mH/2.5 ohm resistor for BSC. Yuck! Sounds muddy, boomy, like I put the speakers inside of a cardboard box. High end treble gone? I've gotta get a mic & preamp & start measuring frequency.
FWIW, I also included a driver brace as recommended in the original thread.
Of course, I put the zobel & BSC inside of the box, since I was "finishing" it
. (They now they look great, just sound awful) This weekend I'm going to pull it out, re-stuff, and try the darned thing again, but with just zobel, just BSC (and do them external), just driver brace... the way I should have.
tcpip said:
BTW since you are the only person i know in India that has Jordan drivers of recent vintage (I knew of someone with the original jordan 50mm modules) how would you compare them with say a B&W 303, Epos ELS 3, Castle Richmond, Quad 11L or other speakers in that price range ($300-500/pair). The 92s cost about $270 per pair. add another $100 for cabinetry and we are looking at $350-400 per pair. I am looking at 3 pairs of a 6.1 system driven by a Marantz SR7000. The subs would be 4 x 12" (have not decided on the configuration yet) powered by a Carver 1.0t.
The sole reason for using the Carver is that it runs cool even in "virtually encolsed" conditions.
my intention is to use the system for HT and some music. the boxes i hope will look like something this http://www.musicalapproach.co.uk/news/KEF_KHT_9000.jpg
one other alternate i am considering (mostly due to WAF and my limited wood working skills) is speaker like the triangle titus, snell type Q, ALON/NOLA LITTLE RASCAL III, Monitor Audio 2.5, etc.
Sorry Navin, no idea how those others sound. But I know some people who have heard very expensive finished speakers (e.g. Avalons, Dunlavys) and who then heard my Jordan drivers and said they sounded excellent. This is a very roundabout testimonial, but this is the best I have.navin said:
I bought them from the UK, and EJ Jordan sold them for UKP 77 each, I think. That makes it more like USD 200 per pair, I'd have thought. And my cabinetry costs for small ported cabinets was about Rs.5000 per pair, which tallies with your figure. However, if you will add a sub, you might as well make even smaller cabinets (e.g. the sealed cubes on the Jordan site), and cut costs a bit further, specially since you are talking of making half a dozen.
I don't know whether it's very important to you to really compare the Jordan against any specific benchmark. If not, then just try one pair and see for yourself --- they are so good that they will not disappoint you by any absolute standards.
thanks for everything TCP. madisound i think has them listed for $135 each. Also I hope they offer a dicsount when someone is nuts enough to get 6.
my other alternate was the FX120 from Fostex. i hear is sounds great and it's big brother FX200 is part of the holy grail fullrange system on the fullrange driver site. but it has a 70Hz limit, a Xmax of only 2mm and is limited to about 10W rms. the difficult part of many fostex drivers is that few affordable LF units match their sound. otherwise drivers like the FF85K and the FX120 would be nice to try in a 1.5 way.
my other alternate was the FX120 from Fostex. i hear is sounds great and it's big brother FX200 is part of the holy grail fullrange system on the fullrange driver site. but it has a 70Hz limit, a Xmax of only 2mm and is limited to about 10W rms. the difficult part of many fostex drivers is that few affordable LF units match their sound. otherwise drivers like the FF85K and the FX120 would be nice to try in a 1.5 way.
Zobel with Jx92s - evaluation
Just finished pulling my my BSC/zobel out of my GM-designed Jordan MLTL's.
So:
With driver brace, zobel, BSC removed - I've got my nice speakers back!
With the driver brace - no difference with it tightened/off that I could tell.
With the BSC -
a little better on the lows. Drums & bass sound like drums & bass. Might be a little boomy, but I'll wait until I get my mic & preamp and measure the frequency response.
With the zobel - the highs are gone, baby, gone
.
So it's now running with the BSC (1.2 mH 2.4 ohm parallel). Michael McDonald sounds nice and full, which makes the spouse happy... which makes me happy
Just finished pulling my my BSC/zobel out of my GM-designed Jordan MLTL's.
So:
With driver brace, zobel, BSC removed - I've got my nice speakers back!
With the driver brace - no difference with it tightened/off that I could tell.
With the BSC -
a little better on the lows. Drums & bass sound like drums & bass. Might be a little boomy, but I'll wait until I get my mic & preamp and measure the frequency response.With the zobel - the highs are gone, baby, gone
. So it's now running with the BSC (1.2 mH 2.4 ohm parallel). Michael McDonald sounds nice and full, which makes the spouse happy... which makes me happy
navin said:
Navin,
pics below:
An externally hosted image should be here but it was not working when we last tested it.
As you can tell, these are now the fronts for HT. We played the Star Wars DVD's the last couple of days. Very good.
An externally hosted image should be here but it was not working when we last tested it.
The speakers are made of oak-veneered MDF, cut 45 deg on edge for the joints. The top was oak veneer glued on with contact cement; the edges on the sides facing the front have iron-on veneer. No joints visible. Finish is stain + several coats of polyurethane; I used 000 steel wool after the final coat.
Music... most often played between the spouse and I
Older stuff: Police, Steely Dan, Eagles, Elvis Costello, Elton John... all sounds pretty good.
Female vocals k.d. lang, Indigo Girls, Mary Chapin Carpenter, Alison Krauss (sounds wonderful on the speakers)
a little (alt)-country - Dixie Chicks, Lyle Lovett, Neko Case
My brother-in-law said that Dave Matthews was so-so before BSC, with it I can't get him from in front of the speakers...
Things that sound lousy:
The Beatles One album (sounds harsh?) - can't even play it.
Eric Clapton/Derek & the Dominos/Layla sounds really thin & flat.
Next steps:
1) Get a preamp & mic & learn Speaker Workshop! See what additional tweaks might be necessary.
2) Build a sub - I'm thinking of a Shiva, sealed.
cheesehead
cheesehead said:
thanks. you mean to say u run these fullrange for HT with no sub at the present? wow! HT usually requires a lot of air esp for the special effects. my intention is to run these from my HT/AVR with the AVR speaker set up set to small (XO at 100hz).
Have you tried heavier music (Black Sabbath, Aerosmith, Who, Stones, AC/DC, etc..). which beatles album sounds flat i have quite a few of them. Do other EC albums sound thin too (I assume this is after BSC)?
thanks again and sorry for being such a pest.
Yes. And the speakers are set for "large" with the LFE re-directed to them. It's not the full experience, but it's still pretty darned good. I could feel explosions through the floor when my kids were watching the original Star Wars downstairs.navin said:
Don't have much of that; what I have is on vinyl and my turntable or receiver/preamp are screwed up. I've got the Beatles One on CD, and it's not flat, it's harsh. (Treble pumped up too high on the remaster?) Elvis Costello sounds fine, but those are rips I did from LP --> CD.
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