MJK’s Jordan JX92S OB with a Goldwood GW-1858 Woofer in an H Frame - diyAudio
Go Back   Home > Forums > Loudspeakers > Full Range

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 19th October 2008, 12:33 AM   #1
diyAudio Member
 
Jim Shearer's Avatar
 
Join Date: Jun 2007
Default MJK’s Jordan JX92S OB with a Goldwood GW-1858 Woofer in an H Frame

(If there was another thread on this, then sorry. I couldn't find it with the search.)

Just got back from listening to Martin’s OB’s with the Jordan JX92 and the 18” Goldwood woofer. Brief analysis:

Let me begin with the bass: WOW!! full, rich bass; lots of detail & nuance. I have been using sealed and ported subs for decades, but this is the bass I want! We didn’t get around to trying the 1812 Overture, but on Temple Caves (from Mickey Hart’s Planet Drum CD) the bottom end was all there. How much deeper do they go? Don’t know, but I’m sure they get down into the 20’s. And at about $60 per driver, they aren’t just great sounding, they’re a STEAL! For those evaluating bass systems: you owe it to yourself to check this out--don’t be discouraged by the naysayers; like Obi-Wan said: Trust your ears Luke. Trust your ears!. I have to look into how the Eminence Alpha 15” driver from Martin’s earlier project would do in an H frame. I suspect that it would go deep enough to satisfy me, and in a bit smaller package.

As for the Jordan: it does nothing wrong. Its sound is smooth, with flat response and good HF extension, but it didn’t grab me. I think it doesn’t have the detail and ‘bite’ (for lack of a better word) that I would like to hear. It’s very listenable, but it didn’t excite me. When Martin switched over to the Lowthers in his MLTL, everything suddenly blossomed--sound stage expanded, detail and nuance increased, and I was engaged by the music. I know that it’s not fair to compare the Jordans to the Lowthers, as they aren’t in the same price league, but hey, there it is. Perhaps if I spent more time w/ the Jordans, I would come to appreciate them, but for now: sorry, they just get a shrug.

And don't think I'm down on OBs. I listened to Martin's original OBs with Lowthers and dual Alpha 15's--those are simply amazing!

Cheers, Jim
__________________
A day without music is like a day without food.
  Reply With Quote
Old 19th October 2008, 02:27 AM   #2
diyAudio Member
 
bluemartini's Avatar
 
Join Date: Nov 2004
Location: ohio
So if you were to rank the three speakers I assume it would be

1. Lowthers in the MLTL
2. Lowthers in the OB
3. Jordans in the OB

?????????

Mike
  Reply With Quote
Old 19th October 2008, 03:12 AM   #3
diyAudio Member
 
Godzilla's Avatar
 
Join Date: Nov 2005
Location: New York
Can I go to Martin's house and listen?
  Reply With Quote
Old 19th October 2008, 01:28 PM   #4
diyAudio Member
 
Jim Shearer's Avatar
 
Join Date: Jun 2007
Mike,

I think I'd say:

1. Lowthers in the OB

2. Lowthers in MLTL

10. Jordans in OB


The Lowthers in the OB are perhaps the best speakers I have ever heard. (Without having speakers in a side-by-side test, it's a bit hard to be absolutely certain.) Too big & too expensive for me to build them, but they are truly spectacular.

Cheers, Jim
__________________
A day without music is like a day without food.
  Reply With Quote
Old 19th October 2008, 02:22 PM   #5
diyAudio Member
 
InclinedPlane's Avatar
 
Join Date: Jan 2007
Location: Maine
The Alphas and the Goldwoods give nice extension, good midbass and plenty of output but the motors are too weak to do the job right, I found. When I switched to the Pyle PPA15 I found that the bass was much quicker and tighter. But with the lower Q they didn't have as much output in OB. I'm interested in the SI Augie but put off by the advertised 'mass disc'. The moving mass needs to be as low as possible for accurate sound and to make the cone heavier just to raise the q with an already smallish magnet makes me cringe.
__________________
I must confess my favorite music is that made by the Rolls Royce Merlin.
  Reply With Quote
Old 19th October 2008, 04:05 PM   #6
diyAudio Member
 
bluemartini's Avatar
 
Join Date: Nov 2004
Location: ohio
Too big I could live with, but the expensive part I am with you. $2000 plus for the Lowthers puts me off as well. I built Virtual MLTL with the Fostex 206e and that was very good. I then put the 206e in the Half Chang by Scott Moose and was very pleased with them. I think you did as well?

Back in July I built Martin's OB with the Fostex 103e and have been with them since. More base from the 15" Alpha's did the trick for me. Very very good to listen to my jazz collection and female artist.

I did see a thread on using the 206e with the 15" Alpha's but have not seen any additional post there lately.

Thanks for the ranking

Mike
  Reply With Quote
Old 19th October 2008, 04:28 PM   #7
diyAudio Member
 
Godzilla's Avatar
 
Join Date: Nov 2005
Location: New York
A sealed powered sub has never integrated properly with my BIBs. Bass sounds boxy. I am thinking now about building two OB subs using the Eminence or Goldwood. I was wondering if using a separate amp to power the OBs would provide any advantages such as volume matching, crossover control, etc.

I may open a new thread to discuss using OB as bass extension for BIBs.

TIA,
Godzilla
  Reply With Quote
Old 19th October 2008, 05:51 PM   #8
diyAudio Member
 
Jim Shearer's Avatar
 
Join Date: Jun 2007
InclinedPlane,

The goldwood was in no way deficient. Bass is clean, detailed, nuanced. I see nothing to be gained by spending more on a low Q driver. The active cross-over and separate amp allow it to be dialed in perfectly. And if you move them around or your taste changes, they can be easily re-adjusted. If you want to use a low Q driver, why not put it in a suitable box where it will work better?


Mike,

Yes, I did make a pair of HC's w/ FE206E's. And every time I visit our daughter & son-in-law, I listen to them w/ great pleasure. They sound very good to me whether they are playing at a whisper or a roar, something that eludes most commercial speakers. (At least in my experience.)

Cheers, Jim
__________________
A day without music is like a day without food.
  Reply With Quote
Old 19th October 2008, 11:19 PM   #9
MJK is offline MJK  United States
Account disabled at member's request
 
Join Date: Feb 2002
Location: Clifton Park, NY
My approach to bass drivers for OB/dipole design is based on the following logic.

1) At 200 to 400 Hz there will be a hump in the SPL response due either to the OB geometry or due to the first resonance of a U or H frame.

2) I set the acoustic crossover to a full range or midrange driver to take advantage of this response and to mitigate the hump. So I cross over the bass driver using a 2nd order low pass filter set between 100 and 200 Hz. Then for the full range or midrange driver, I set the high pass filter between 200 and 400 Hz depending on the crossover slope.

3) I don't use EQ so I always look for a high Qts (~ 1.0) driver with an efficiency that is at least 6 dB greater than the full range or mid range driver. If the efficiency does not look adequate, I will use the boost feature in my active crossover. But this means a passive crossover option is not in the cards at a later date.

4) This combination, if done correctly, will yield a reasonably flat SPL response that will go deep enough to surprise a lot of people who think of dipole systems as being light in the low frequencies.

What this really means is that the bass driver is only driven from fs to approximately 200 Hz. This is well below any cone break-up modes or frame ringing problems. Any decent large diameter pro driver with a high Qts will behave as a piston over this frequency range. There will be no flapping cone or booming resonant bass. The driver will be under complete control of the amp.

So I look for a high Qts driver (~ 1.0) and a decent fs. If you are going to use an OB, then an fs of 40 Hz is adequate since in a reasonly sized OB you are not going to get below 40 Hz without EQ. For an H or U frame driver, look for a lower fs. Achieving 20 Hz in an H frame is easily possible. Based on these requirements, I have found that 15" or 18" bass drivers priced between $50 and $70 will be perfectly adequate for a music system. I don't know anything about home theater but I suspect the same low cost drivers will also be acceptable. I don't see any reason at this time to spend more on the bass driver.

The more expensive IB or OB 15" drivers will have a much larger Xmax compared to the cheaper versions. But my experience is that with music, even played at loud volume levels, the cone's barely move. I did subject my Goldwood H frame to the 1812 overture this past week. I played it through twice, once to listen and once to watch the cone motion. My 16 year old son was laughing telling my how cool it was when the floor shook. Watching the cone, at a fairly high volume level produced by a 200 W SS amp, I estimate they moved about 1/2" peak to peak. No damage and no bottoming of the voice coil. Would a more expensive driver have done a better job, maybe but this is not something I do on a daily basis so I am not really interested. For music, I have not experienced any problems where the cone motion approachs the stated Xmax of the cheaper drivers.

I would rank my systems that Jim and I have listened to in this order of increasing in performance.

1) Jordan JX92S and Goldwood H frame - the Jordan driver is as Jim discribed. He was not too fond of it but I can see where others might like it more then he did. It is smooth and kind of layed back. All the frequencies are reproduced but not with the lifelike performance of the Lowther DX3. I am still going to try a few other similar sized full range Fostex drivers to see if I can close the gap to the Lowthers, that would be really nice price wise and maybe even allow a passive approach to the crossover.

2) Lowther DX3 ML TL - compared to the Jordan with the H frame this system is bass light. Better detail and dynamics but probably not acceptable to a bass fiend. Good for acoustic music.

3) Lowther PM2A with 2 Eminence Alpha 15A drivers on a huge OB - a big improvement over 1) and 2). No comparison as far as big sound and dynamics goes. The bass does not go nearly as deep as the H frame.

4) Lowther and Goldwood H frame - This is probably my next step and was mocked up when Jim and I combined the Lowther DX3 ML TL with the Goldwood H frame using my active crossover. This has the potential of much deeper and better bass then the Alpha 15A OB system while still using a Lowther for everything above 200 Hz. I can see this combination being another big step up in performance. This will require 8 to 10 dB of boost to be applied to the Goldwood to match the efficiency of the Lowther, maybe it would later benefit from a pair of Goldwood H frames per side. Think about $2k of Lowther drivers mated to $120 of Goldwood bass drivers, seems wrong but no question in my mind that it will be a killer set-up.

Jim and I had a lot of fun yesterday afternoon. Jim has put together a test disc with all kinds of music styles and effects which really tested my system. Some of the selections are well known and some I have no idea where he dug them up, but it is an interesting listening experience.

Hope that rather long dialog is of some use,
  Reply With Quote
Old 20th October 2008, 03:33 AM   #10
diyAudio Member
 
Godzilla's Avatar
 
Join Date: Nov 2005
Location: New York
>>> Think about $2k of Lowther drivers mated to $120 of Goldwood bass drivers, seems wrong...

It does! But who's complaining? Martin, do you think the Goldwood in the H frames as you designed would work well with BIB's? My feeling is to leave the BIBs playing full out and changing the crossover on the H frames. I was thinking about lowering it to 50hz to 100hz and fiddle with the volume control of a dedicated amp to make it work. Your H frame design will sit nicely in front of my BIBs without obstructing them. The H frames could be moved forward or backwards and side to side for best results. I am excited about your H frame ideas! Thanks!

Godzilla
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Looking for Jordan JX92S oshifis Swap Meet 5 28th December 2013 12:26 AM
Canadian GB for Goldwood GW-1858? Aengus Group Buys 93 16th September 2009 03:11 PM
Jordan JX92S Gaffer74 Full Range 11 31st May 2006 09:42 PM
jordan jx92s TL box pstephenson Full Range 3 26th October 2004 12:56 PM
8" 4 ohm heavy duty woofer/midbass needed, who's Goldwood? eRiCdWoNg Multi-Way 11 29th February 2004 06:11 PM


New To Site? Need Help?

All times are GMT. The time now is 01:29 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2