What is better than JXR6 HD - Current state of the art drivers for FAST / WAW

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Hi,

For the last 10 years I have been listening to a DIY Jordan JXR6HD nearfield desktop and peerless 8" subwoofer FAST system (2.1 design, active crossover with LT for woofer & Tripath amps) which has done very well over the years. As I spend hours each day listening to music while using the computer I'm thinking after 10 years there must be better solutions available.

For this setup I'm about to build a 2.1 amp based on the new TI TPA3251D2 class D IC (which has excellent distortion specs) and use software for the Linkwitz transform and crossover, so I'm wondering about the options for new desktop / FAST drivers/speakers. I want a similar FAST setup, ideally with small drivers 3" to 5" for the desktop and a 6" to 8" woofer, images well with good transient / dynamic response (so enclosures will be sealed and metal cones peferred). Both subwoofer will be in the corner and firing downwards for extra bass boost as I want a smaller woofer box. Desktop units will be about 2L, against the wall and I sit about 2 feet away from the desktop unit (toe in so on axis and at ear height), room is large for a bedroom, a little smaller than living room size, and I listen to rock so low end response is important and I like clear & fast highs.

I thought EJJordan were going to release another small full range driver like the JX6HD however there hasn't been any news about that for a while so I guess not. The new Eikona looks nice but a little too big for the desktop and I don't need such a large driver as I'll be using a subwoofer and want to limit desktop space. It seems the 10 year old JXR6HD is still rated pretty well but I haven't been keeping up with the latest driver developments to know if there is anything that will beat it now. I see Mark Audio is about to release a spiderless 4" alpair 5 generation 2 which looks very interesting (and can be crossed over lower than the JXR6HD) although the JXR6HD has better bottom end response for a smaller box according to a quick comparison via winISD (JXR6HD = orange winISD plot, bottom SPL plot. Alpair 5 gen2 is yellow winISD plot, middle SPL plot).

513302d1446966831-jxr6-hd-current-art-drivers-fast-jxr6hd-vs-alpair-5-gen2-jpg


However I'm not sure if there are other current drivers that would better the JXR6HD.

As I'm using a fairly generic peerless woofer there should be a number of better bass drivers available now - the Dayton RS225-8 aluminum cone woofer looks to be popular for small FAST configurations, but there may be more suitable units, I'm particularly looking for a unit that can keep up with the desktop metal cone (assuming I keep the JXR6HD or use the Alpair 5 gen 2) so a 6" metal cone woofer would be ideal with LT in a small sealed box.

Given the above usage scenario (desktop FAST with good detail & transient response), any suggestions on the best drivers and design that should beat my current FAST setup?
 

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frugal-phile™
Joined 2001
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I've not heard the Jordan. I have had JX92s (3 times) and it didn't do anything for me if that helps.

I am one of those fortunate enuff to have a set of A5.2 (a 3" driver). It is very good and works in 2 litre -- we put it in a miniOnken -- it may not go low enuff sealed. We also treated it with the expected improvements.

We haven't compared it to our long-term favorite FF85wKeN… it is gonna be close.

TI TPA3251D2 class D IC (which has excellent distortion specs)

Likely more power than you'd need. And i get the impression it is aimed at lower impedance loads.

Questionable whether the distortion specs mean much below a certain level… I didn't see anything meaningful on the data sheet.

dave
 
Thanks Dave.

Agree that amp distortion is orders of magnitude better than the best drivers. The TPA3251D2 represents the current state of the art class D from TI and is also a 4 channel IC which can run the desktop pair single ended (35w into 4 ohms) and the subwoofer bridged (140w - will need the power to drive the woofer with a LT) so should make a compact and good sounding amp. I also have a couple of these chips waiting for an application.

For the A5.2 driver when sealed and you say not going low enough - I assume you are agreeing with my quick winISD model which indicates cutover to the woofer should be 150Hz - 160 Hz, instead of the 120Hz that the JXR6HD can go to? 150 Hz is a little high for a FAST system (ideally 100 Hz or below crossover). I'll check out the FF85wKeN as well.

What are your expected improvements?

Any ideas on a reference matching woofer for FAST?
 
frugal-phile™
Joined 2001
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Agree that amp distortion is orders of magnitude better than the best drivers.

That is not what i'm getting at. You say it is low distortion, but when i looked at the data sheet the only reference to distortion given is THD, and that is a near totally meaningless spec.

The distortion that is usually measured in speakers is also bout that meaningless.

http://www.diyaudio.com/forums/loun...e-answer-subjective-world-10.html#post4464798

The TPA3251D2 represents the current state of the art class D from TI and is also a 4 channel IC which can run the desktop pair single ended (35w into 4 ohms) and the subwoofer bridged (140w - will need the power to drive the woofer with a LT) so should make a compact and good sounding amp. I also have a couple of these chips waiting for an application.

The 4 channels is nice for that kind of application.

For the A5.2 driver when sealed and you say not going low enough - I assume you are agreeing with my quick winISD model which indicates cutover to the woofer should be 150Hz - 160 Hz, instead of the 120Hz that the JXR6HD can go to? 150 Hz is a little high for a FAST system (ideally 100 Hz or below crossover). I'll check out the FF85wKeN as well.

150 Hz is a low XO for a FAST… usually you see a higher XO. My sim shows a max flat sealed alignment with an F3 just below 140 Hz. FF85 doesn't go as low. In FASTs we typically XO them 240-350 Hz.

What are your expected improvements?

Treated drivers have better DDR/detail, capable of reproducing lower level information better. Things that make voice & instrument sound closer to real. A better 3D image is one of the big benefits.

Any ideas on a reference matching woofer for FAST?

You might look at the Silver Flute W14. I have fitted it into 5 litres with decent bass response.

We keep looking, one of our favorites was the SDX7 but it is NLA.

dave
 
OK - my point on the amp distortion is that a good amp has much lower distortion than a speaker, so the choice of amp is typically less critical than the speaker. I don't have any other test data about the TPA3251D2 to make a good objective assessment except that TI have improved the class-D technology used in this chip - I doubt it would be a bad choice for this configuration. More on this chip here: http://www.diyaudio.com/forums/class-d/276982-tpa3251d2.html. However this thread is more about the driver choice for desktop & subwoofer rather than the amp.

150 Hz is a low XO for a FAST… usually you see a higher XO. My sim shows a max flat sealed alignment with an F3 just below 140 Hz. FF85 doesn't go as low. In FASTs we typically XO them 240-350 Hz.

I forgot to mention that I will be using one subwoofer not 2 in the FAST configuration and the subwoofer will be located off-center. Due to the directional nature of sound above 100Hz you really don't want a 2.1 FAST system with a crossover higher than about 150Hz.

You might look at the Silver Flute W14. I have fitted it into 5 litres with decent bass response.
OK will look into this driver.

Thanks for the feedback so far.
 
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frugal-phile™
Joined 2001
Paid Member
OK - my point on the amp distortion is that a good amp has much lower distortion than a speaker, so the choice of amp is typically less critical than the speaker.

The distortions are typically quite different. The amp is just as important as the speaker. For instance an amp can have higher order distortions that are really hard to get out of a speaker and the ear is very sensitive to those.

I doubt it would be a bad choice for this configuration.

I doubt it would be a bad choice either.

one subwoofer not 2 in the FAST configuration and the subwoofer will be located off-center. Due to the directional nature of sound above 100Hz you really don't want a 2.1 FAST system with a crossover higher than about 150Hz.

I'd go with a miniOnken style enclosure (high vent resistance overcomes many of the issues with a typical vented system).

I am currently using a pr µMar-Ken5.2 XOed at 100Hz to a pr of push-push SDX10 subs.

dave
 
Interesting - your miniOnken enclosure is almost exactly the same shape as the desktop speakers I currently use which I built in 2006 (although sealed) with the bottom plinth, shape and 45 degree sides, although the speakerbox I use is considerably smaller (180mm x 440mm). The miniOken wouldn't fit on my desk. Still would prefer sealed for better transient response (IMO a better match for metal drivers for a small cabinet).
 
frugal-phile™
Joined 2001
Paid Member
Still would prefer sealed for better transient response (IMO a better match for metal drivers for a small cabinet).

Maybe.

2 litre, 100 Hz sealed is REALLY going to limit driver choice, and you'll likely give up stuff higher up.

In our FASTs we typically use a midTL, but you need to go too low for that.

There is a 2L µMar-Ken5.2. One for the FF85 as well.

dave
 
Founder of XSA-Labs
Joined 2012
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Have you looked at the 5 Subjective Blind Listening test threads? Many of the state of the art drivers and some basic ones were all tested and recorded with a FAST setup. Listeners picked their favorite sounding ones.

Briefly the top ones that measured well and were picked include:

Visaton B80, SS 10F/8424, Vifa TG9FD10-8, Peerless P830986, SBA SB65WBAC25-4, and Dayton PS95-8

If you like the sound of ultra low distortion, the 10F is the tops.
 
That sure is a Mt Everest peak on that woofer however rolling off above 150Hz should kill it even with a shallow filter. Higher order cone harmonics may still be a problem though.

Seems like the JXR6HD is still a decent driver even for its age although I would like to try something different. Would be interesting to see a comparison between the new Mark Audio alpair 5.2 and the JXR6HD.

Colin, any updates from EJJordan on a possible update to the JXR6HD?
 
I could be wrong, but this suggests not - at least presently
JX92S and JXR6 drive units

Over the years, we have produced a number of loudspeaker drive units, all sharing the common philosophy of wide bandwidth, fast transient response and versatility in use. From the original Jordan-Watts Module in the 1960s to the more recent JX92S and JXR6HD, these units have been very successful at capturing the essence of live music.
Both these units are now superceded by the Eikona.
Click the titles below for full specs for these drive units. At a later date we will add the JX53 and the JX125 and JX150 bass units.

Not being as fluent in Jordanese as Colin would be, I read that last sentence to imply that the entire JX series has been superceded by the Eikona, with no current plans for smaller diameter models.
 
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