Which high-xo tweeter to use with a Jordan JX92S?

[tcpip]

What high-xo tweeter to use with a Jordan JX92S?

I have a pair of JX92S drivers sitting around for two years in small ported boxes. I now want to try using them as wide-range midranges (in a manner planet10 keeps advocating). I therefore want help on what tweeter to use for these?

I guess I'll be crossing the tweeters at something between 4K and 6K, 2nd or 4th order. (I'd usually prefer 4th order, but because the xo freq is so high, I may use lower order if I go with a dome. For planars/ribbons, I don't know.)

What tweeter should I use? If the xo freq was lower, I'd use a Seas TBFC/G or a Vifa D25AG35: affordable and clean. Is there anything better than these given my xo freq is much higher this time? The parameters I'd look for will include:

• flat FR (no surprise there)
• low distortion
• good dispersion pattern, both horizontally and vertically. Each tweeter will be mated to one JX92S, not an MTM.
• good matching with the metal cone of the JX92S
• subjective impressions

I will be open to implementing this thing in active or passive xo. I don't need huge SPLs, and the JX92S doesn't do huge SPLs anyway.

My budget for each tweeter is $100, excluding shipping.

I have zero experience with planars/ribbons... I've probably never even seen them. I have read that they are great if the xo freq can be highish, so I was wondering whether any of them will be your recommendation?

If I don't get a clear indication from you guys, I'll fall back on the Vifa or the Seas domes I mentioned earler. One thing is clear: I'm pretty sure I'll prefer the sound of the JX92S with a good tweeter + a good xo compared to a plain single-driver JX92S.

 

[EC8010]

The key thing is that all drivers have faults and you can almost always hear the characteristic sound of the material of the moving mass. If you change from one material to another it tends to highlight the crossover. Thus, if you have an aluminium cone midrange, it would be best matched to an aluminium tweeter. Aluminium dome tweeters tend not to be very good (and not in the same league as the JX92s), so the best choice is a ribbon tweeter. I have heard JX92s with the Fountek ribbon crossed over at 7kHz and it sounded good.

 

[jbateman]

Just follow these plans:
http://www.creativesound.ca/pdf/JX92SG2siDesignPak.pdf

 

[tcpip]

Aluminium dome tweeters tend not to be very good (and not in the same league as the JX92s), so the best choice is a ribbon tweeter. I have heard JX92s with the Fountek ribbon crossed over at 7kHz and it sounded good...

The NeoCD3.0 seems very affordable. I guess the xo should also be pretty easy to build, because both SPL and impedance seem fairly flat, as with most ribbons.

I wonder what the distortion and ETC readings are like for these ribbons?

 

[tcpip]

Just follow these plans:
http://www.creativesound.ca/pdf/JX92SG2siDesignPak.pdf

Thanks for this ready-made design. I might go for this and then add a woofer for the last two octaves. At least, it gives me some very concrete pointers to one good design. I'll probably use this ribbon tweeter or the Fountek NeoCD3.0, unless I hear otherwise from some of you. Both these ribbons seem to have fans, and are in my budget.

 

[tcpip]

Any other suggestions?

I got one suggestion which pointed me towards ribbons in general, and another to a specific design which used the G2Si. Both were very useful pointers, but is there absolutely no other opinion on this subject from anyone else?

Specifically, are we all of one mind that there's absolutely no tweeter better than the G2Si for high-xo situations, at $100 or less?

Thanks for your help.

 

[DIY_newbie]

Re: Any other suggestions?

I got one suggestion which pointed me towards ribbons in general, and another to a specific design which used the G2Si. Both were very useful pointers, but is there absolutely no other opinion on this subject from anyone else?

Specifically, are we all of one mind that there's absolutely no tweeter better than the G2Si for high-xo situations, at $100 or less?

Thanks for your help.

I prefer bigger ribbons like the fountek JP2.0 if you can get one. I have no experience with the NeoCd series, but since its film/foil hybrid I would assume it will sound more like a planar tweeter than a pure aluminum ribbon. IMHO the longer ribbon gives a warmer sound without loosing detail. You could do much worse than the pure aluminum G2si...

--Chris

 

[EC8010]

Yes, despite them often being marketed as "ribbons" the plastic film with thin conductors and no transformer is a different beast entirely. Many years ago, Wharfedale osld a headphone using this principle as referred to it as "isodynamic" because the drive was applied over (nearly) all the surface. I think that was the right name for a technology that is essentially a flexible PCB held in front of some magnets. By contrast, a true ribbon has a corrugated aluminium foil suspended between the pole pieces of a powerful magnet. The difference is that the true ribbon has a lower moving mass and operates in a constant magnetic field, whereas the isodynamic drver has a necessarily higher mass and operates rather nonlinearly because the field is applied from the back only. It's a bit like single-sided electrostatics vs proper push-pull...

Go for the true ribbon, You won't regret it. (I bought a pair of ESG1 to go with my JX92s but haven't got around to making the boxes yet.)

 

[tcpip]

Go for the true ribbon, You won't regret it. (I bought a pair of ESG1 to go with my JX92s but haven't got around to making the boxes yet.)

Okay, will do the G2Si then, unless some of you can come up with a good reason why now.

BTW, what's the ESG1, and where is it sold?

And what about woofers? I want to take the JX92S down not below 100Hz. I want to xo this driver to one or two woofers. Will the Dayton RS 10" woofer (not the subwoofer but the woofer) used in one push-push pair per side be a good idea? I'll need four woofers, but the resultant sound, perhaps in a sealed enclosure, may be good. Any other ideas of woofers to mate with the JX? (No, I don't want to use the 6" Jordan woofer.)

 

[Jim Griffin]

Answers to Your Questions

tcpip,

Answers below:

1. BTW, what's the ESG1, and where is it sold?
E-speakers (a supplier of Aurum Cantus products in the US) designated the A-C ribbons by the ES leading initials a few years ago. I think that they have gone away from that designation at this time. Hence, the A-C G2si was designated as the ESG2si and such. You'll want the G2si for my design which was referenced earlier.

2. And what about woofers? I want to take the JX92S down not below 100Hz. I want to xo this driver to one or two woofers. Will the Dayton RS 10" woofer (not the subwoofer but the woofer) used in one push-push pair per side be a good idea? I'll need four woofers, but the resultant sound, perhaps in a sealed enclosure, may be good. Any other ideas of woofers to mate with the JX? (No, I don't want to use the 6" Jordan woofer.)

I suggest that you build the JX92S/A-C G2si mini-monitors exactly as I outlined in my write-up. Hence, the box size would be a 7 to 9 liters (0.25 to 0.3 cu. ft) volume. As I mention in the write-up you can seal their boxes and get excellent performance to below 100 Hz which would be ideal for your needs. Alternately, build just add the port tube but stuff it with so effectively you have a sealed box and you'll have the same performance.

You can use the new Parts Express Dayton RS line of woofers with the aluminum cones (these are actually are subwoofers). If you have a small or medium sized room, likely one woofer per side would be adequate but if you want more bass you can go with 2 per side. I like the tight bass that you get from sealed subwoofers. Depending on room gain you may wish to boost the bass to extend the low end a bit to your taste. Of course you will need crossover(s) and amplifier(s) (plate amps?) for these woofers. I would cross over at 100 Hz with a 24 dB/octave low pass on the woofers and a 12 dB/octave high pass on the satellites. Thus, you'll have acoustically a 4th order crossover.

Other woofers/subwoofers can likely be used if they can deliver as desired for a sealed enclosure.

Jim

 

[tcpip]

Re: Answers to Your Questions

Originally posted by Jim Griffin

Good to hear from you. I've been reading your stuff for some time now, as have many others on these pages, I guess.

Hence, the A-C G2si was designated as the ESG2si and such. You'll want the G2si for my design which was referenced earlier.

Okay.

I suggest that you build the JX92S/A-C G2si mini-monitors exactly as I outlined in my write-up. Hence, the box size would be a 7 to 9 liters (0.25 to 0.3 cu. ft) volume. As I mention in the write-up you can seal their boxes and get excellent performance to below 100 Hz which would be ideal for your needs.

Yes, I'll certainly use a sealed box for the JX92S. I am just not sure I'll want that low a bass impact. I've already listened to the JX92 in a ported box for more than a year, so I'm basing my judgement on this.

You can use the new Parts Express Dayton RS line of woofers with the aluminum cones (these are actually are subwoofers).

Why do you call them subwoofers? Basically, what defines whether a driver is a woofer or a subwoofer? Sorry if it's too basic, but I'm not clear on this. I used to believe that any driver meant for only the last two or three octaves is a subwoofer, while a driver which can cleanly go a bit higher, say till 500Hz or so, is a woofer.

If you have a small or medium sized room, likely one woofer per side would be adequate but if you want more bass you can go with 2 per side.

You're totally right about one woofer per side being adequate... it's just that I've been reading a lot about how the JX92S is a very high-quality driver and should only be mated with equally high-quality partners, and how having a twin-opposed pair of woofers cuts down distortion. I've also read about how adding cone area (two woofers instead of one) helps to reduce excursion per driver, hence reducing linear distortion. Hence my entire set of doubts about woofer selection, using them twin-opposed, and so on. I just didn't want to yoke a racehorse to a bullock cart.

Actually, I'd probably be happier using a single front-firing woofer instead of two, as far as SPL requirements go --- I'd also be able to xo the woofer to the JX92S at a higher freq. I suggested two just to get the distortion cancellation benefits, and this of course forces me to take the JX92S down to 100Hz or so, to allow side-firing woofers to work cleanly.

... you will need crossover(s) and amplifier(s) (plate amps?) for these woofers.

I was thinking of going fully active, actually, till I saw your ready-made design for the mid-to-upper portion. Therefore, I'll go with your passive xo for the top two drivers, and go active for the low end.

I would cross over at 100 Hz with a 24 dB/octave low pass on the woofers and a 12 dB/octave high pass on the satellites. Thus, you'll have acoustically a 4th order crossover.

Got it.

Do you feel it's important to cut the low-end signal to the midrange electrically at a freq higher than its natural 12dB/oct rolloff? Some say that one shouldn't allow the midrange to be rolled off by just its acoustic rolloff... it doesn't stop the low freq signals from hitting the coil and causing IM distortions. Is this something I should worry about?

Thanks for the inputs.

 

[DIY_newbie]

Yes, despite them often being marketed as "ribbons" the plastic film with thin conductors and no transformer is a different beast entirely. Many years ago, Wharfedale osld a headphone using this principle as referred to it as "isodynamic" because the drive was applied over (nearly) all the surface. I think that was the right name for a technology that is essentially a flexible PCB held in front of some magnets. By contrast, a true ribbon has a corrugated aluminium foil suspended between the pole pieces of a powerful magnet. The difference is that the true ribbon has a lower moving mass and operates in a constant magnetic field, whereas the isodynamic drver has a necessarily higher mass and operates rather nonlinearly because the field is applied from the back only. It's a bit like single-sided electrostatics vs proper push-pull...

Go for the true ribbon, You won't regret it. (I bought a pair of ESG1 to go with my JX92s but haven't got around to making the boxes yet.)

Ii just wanted to clarify about the NeoCD series. They're built like the true aluminum ribbon, however instead of corrogating the ribbon they simply sandwitch it with film to give it strengths. It acts very much like a pure ribbon, however it has much more mass than the pure aluminum ones. It would almost be a hybrid between Planar and ribbon technology... I have a blown JP2.0 I think I'll have "repaired" with the NeoCD element to compare the sound.

--Chris

 

[Dumbass]

Why do you call them subwoofers? Basically, what defines whether a driver is a woofer or a subwoofer? Sorry if it's too basic, but I'm not clear on this. I used to believe that any driver meant for only the last two or three octaves is a subwoofer, while a driver which can cleanly go a bit higher, say till 500Hz or so, is a woofer.

No hard and fast rule AFAIK.

Those Dayton drivers look good to me, also check out those Hi-Vi ones also at partsexpress.

Once you start getting over $100 per driver, you might want to look at some high-quality 12" subwoofer drivers like the NHT 1259, etc.

Having heard the Jordan drivers, I'm not convinced they want or need a supertweet, but then again I've never heard Jim Griffin's 2-ways, which have excellent reputation. If it were me (and it's not) I'd solve the bass issue first. Perhaps relieving the Jordans of some of their low-freq duties will improve the highs, or not.

 

[soongsc]

Yes, despite them often being marketed as "ribbons" the plastic film with thin conductors and no transformer is a different beast entirely. Many years ago, Wharfedale osld a headphone using this principle as referred to it as "isodynamic" because the drive was applied over (nearly) all the surface. I think that was the right name for a technology that is essentially a flexible PCB held in front of some magnets. By contrast, a true ribbon has a corrugated aluminium foil suspended between the pole pieces of a powerful magnet. The difference is that the true ribbon has a lower moving mass and operates in a constant magnetic field, whereas the isodynamic drver has a necessarily higher mass and operates rather nonlinearly because the field is applied from the back only. It's a bit like single-sided electrostatics vs proper push-pull...

Go for the true ribbon, You won't regret it. (I bought a pair of ESG1 to go with my JX92s but haven't got around to making the boxes yet.)

I think these are what you are talking about. I was just able to look at them at the show. Look neat, but don't know how they sound. I have seen other speakers with similar design and sounded quite well, but the diapham did not look as smooth as this one. According to the data I looked at, the impedance is really flat showing no resonance. The foil is between two magnets as far as I could see, which technically might have an advantage of damping. I kind of wonder how damping would be on traditional ribbon tweeters. I guess if we looked at some waterfall plots, then it would be evident.

 

[EC8010]

This is what I regard as being a true ribbon - a vertical corrugated aluminium ribbon with a magnetic field flowing from left to right (or maybe right to left).

 

[EC8010]

And the rear view gives you an idea of the size of the magnet assembly.

 

[soongsc]

Someone else used a real small tweeter (different thread, you can do a seach with JX92) and seemd to like it. I think it was only about an inch in diameter. It was used in the ceneter channel of an HT system.

Actually the JX92S may not need a tweeter.

 

[navin]

I think the JX92 only needs help above 7-8k maybe even higher only is there any need to roll the JX92 off (other than interpolar distortion).

one reason to use the JX92 (or other fullranges) is to avoid steep crossovers in the 1st place.

 

[planet10]

because the field is applied from the back only. It's a bit like single-sided electrostatics vs proper push-pull...

Not always. Eminent (Bruce Thigpen) has a patent on push-pull planar-magnetic ribbons, and the Monsoon ribbons are licenced to use the same tech. The ribbon tweeter out of the MM500/502 would be the best bet for this kind of ap -- if it is efficient enuff (i'm not sure it is). I'll have a better idea when i pull a set sometime this week.

dave

 

[Cal Weldon]

Re: Re: Answers to Your Questions

Why do you call them subwoofers? Basically, what defines whether a driver is a woofer or a subwoofer?

I'm mystified also. When I started building speakers, a sub had an Fs of 20hz or less, hence the term sub, as in subsonic. Not sure when it changed but nowadays it seems to mean woofer. I guess we just have to roll with the punches and accept it.

EDIT: Oops, off topic

Cal