Jordan JX92s advice

[smallangryboy]

Recently I've been working closely with two very capable forum members, richie00boy and sploo to realise some of my designs. Most notably the Longball and Lowball. The former was designed to temporarily replace my Highball speakers while my daughter grows out of her destructive "shake everything till it breaks" phase, the latter was to partner with the Jordan designs for bass reinforcement and home cinema.

Right preamble over, a couple of questions :

• Has anyone built Sheldon's Tidy TL design based on the Jordan JX92s driver ?
• If so, what sort of room placement do you have, how are they towed in and how far from the walls are they?
• Did you stuff the line and if so how much?
• Did you implement the BC circuit Sheldon designed with the TL?

As I've been fired up about speaker building again, I went head first into creating the TL enclosure for the Jordan's, not quite thinking that they would be partnered with a dedicated sub woofer. They look and sound superb, and sploo has done amazing work with the cabinets, however I've a couple more questions about how the Jordan's perform in larger enclosures.

As the JX92s driver has a dedicated sub woofer, would the 8 litre ported version be more suitable? What I mean by that is am I loosing anything of the performance and sound quality in a larger TL design because the driver is having to do more, and using smaller enclosures and rolling them off to let the sub handle the lower octaves may improve the sound? Or how best to approach partnering the sub to the TL's, would some sort of crossover be a good solution?

[audiobomber]

A sealed cabinet for your main speakers provides the best transition to subs, because the phase is easy to match. There are various ways to mate a sub to a sealed cabinet.

1. Run the mains full range and run the sub with its on-board filter. (2.1 system)
2. Run the mains full range and roll the sub in 2nd-order active low-pass at the F6 frequency of the mains (LR2 crossover)
3. Add a filter to roll off the mains, 2nd-order high-pass, at or near their F3. Run the sub 4th-order LP, -6dB at the mains' F6 frequency. (LR4 crossover)

I've tried all three of the above setups with my speakers (BESL S5-MTM, dual Rocket UFW-10 subs). The main thing in getting a sub/sat system to work is a good measurement tool, so you can see what the sound is doing. I assume you have that covered.

I haven't been able to make the LR2 system sound quite right, but I haven't bothered to try the exact filter for the low pass. I'm temporarily running a 2.1 system while I wait for some crossover parts, and it sounds fantastic, although not as effortless as the LR4 system.

The trick with the LR4 setup is to find a crossover for the mains that doesn't cause more trouble than it's worth. What I mean is, the crossover for the main speakers has to be as transparent as your amps, or it will compromise the sound. I'll be running with a modded Marchand XM46SB passive line-level crossover to roll of the mains (2nd-order HP @ 80Hz), and a Marchand XM44 (3rd-order LP @ 80 Hz) on the subs. The reason I'm using a third-order filter on the subs instead of 4th is that the subs have a natural 6dB rolloff above 100 Hz. So using a 2nd-order HP and a 3rd-order LP results in LR4 acoustic slopes.

Note that adding a sub will not address BSC, which is a separate issue. Another solution for unloading the JX92's, which would give you deep bass and BSC, would be to buy a pair of the forthcoming JX150's and mate them to the JX92's, using a first-order crossover at the BSC frequency.

PS Your JX92 systems are very elegant.

[smallangryboy]

audiobomber many thanks for taking the time to post an extensive reply, and again thanks for your compliments.

I guess I'm really looking at making the most from my new TL designs, and seeking the best way to integrate them with my sub [which I get back on Saturday].

I have faith in my trusty comrade richie00boy that together we can sort this out with a good deal of tinkering and hard work

Worst case scenario is I have to create some of the 8 litre Jordan designs in a floor standing enclosure to match the sub, but I think that might break sploo's heart as he has invested huge amounts of time and energy to create the beautiful Longballs !

[Colin]

The Tidy TL seems to be a fairly traditional TL. Would it be possible to adjust the stuffing of the line to achieve the Q required to match with a sub?

[smallangryboy]

I'm hoping that's going to be the case, plus the sub offers a great deal of customisation options, so fingers crossed we can sort something out.

There are no guides but what would your recommendations be for placement ?

Currently I'm experimenting with them close to the back wall at about 20cm - 30cm and side wall at about 20cm toed in at about 45 degrees.

[Colin]

Toe them in another 15 degrees each to reach Jordan's recommended angle. Moving around closer to walls or corners (or use of BSC) also helps balance the sound. The two traditional TLs I've built seem happy in corners with no excessive bass.

[smallangryboy]

Just thought I'd update.

I've now stuffed the speakers. I decided to add about 300g of polyester wadding to each speaker, similar to the recommendations on the Jordan site for the MLTL designs.

I stuffed approximately half the line, using the guts out of a cheap pillow from Woolworths. This provides excellent polyester wadding, with the added bonus that at it's core it has a denser square pad of polyester, which was ideal when cut in half to place in the cavity directly behind each driver. It also has the advantage of not being branded "acoustic filling" and priced accordingly !

I decided to position the speakers closer to each wall so only 18cm from the back and sides, to experiment with it's effects on bass and overall sound. They are toed in to about 45 degrees not quite the recommended angle but as with the positioning, this crosses the drivers in front of the listening area at about 1m.

The results are excellent. The sound seems more coherent, in that the highs, mids and lows all fit together seamlessly. Vocals are well delivered, there is no brightness in the upper band and the bass is impressively deep for the size of the speakers, and delivered in a smart and timely manner.

All in all for a bit of cheap polyester and some deft positioning a rewarding return !

[Colin]

Excellent, good to read that the fine tuning has worked - and the Woolies tip is a good one.

Ted is always campaigning in favour of wide enclosures. I have a narrow JX92 TL, similar in profile to the Tidy TL (but shorter) and placing a pair of boards either side as 'wings' does fill out the sound. It gives an idea of what BSC can achieve.

[RAndyB]

Smallangryboy,

Your website is very professional looking, and the quality of the cabinets makes me envious.

You seem to have the queries sewn up. But I like talking about the Jordans so...

The eight litre ported enclosures that I built are boomy (my room exacerbates the boom). The TLs control the bass better (usually, but you know that already).

My preference is for small baffles. The top end sounds better and thus you get more detail, it also produces a better stereo image for me.

Placing the cabinets a different distance from the two walls is generally better than equidistant.

I am delighted at how much more detail the JX92S produces as I improve the quality of the electronics. TL082 (please don't laugh) to OPA2134 in the line level BSC made an audible improvement. I have not yet built a power amp. that does not improve the sound.

Andy

[smallangryboy]

Andy

Thanks for the compliment !

I'm a product designer by training and a graphic designer by trade. My expertise only stretches as far as ergonomics and aesthetics, unfortunately my designs are largely borrowed or have a large input from two other forum members whose expertise is in the maths, physics and engineering behind loudspeakers/sub woofers/amplifiers.

However that said, I think almost anyone can build a loudspeaker that will sound decent. It just takes a bit of trial and error, and heavy borrowing from the knowledge of all the people on forums like this one.

There is no definitively "perfect" loudspeaker as peoples tastes and hearing differ enormously. I start by designing something that looks beautiful [after all you are going to be looking at them a lot], then I do a lot of digging to find the technology and expertise that will make it sound beautiful !

I may nee to add a BSC to my design and would obviously appreciate any help.

The next stage for me would be to tap into peoples experience and help to create a whole hifi system, from a 5.1 amp, upto a DVD player and HDD storage !