Fountek JP3.0 vs. AC G2si?

[Saurav]

Hi,

Has anyone compared these two ribbon tweeters directly? I searched the archives, and there's a fair amount of information on the G2si, not so much on the JP3.0 (most people who've used Fountek seem to have used the JP2.0), and I didn't find anything that directly compared the two. They seem very similar (in fact, almost identical), both in specs as well as in price. I might be missing some information, of course, but on paper I don't see much to differentiate between the two. I think I saw some concerns about replacement parts availability and QC, which would become the determining factors if the sonics were close enough.

So, I was wondering if someone has done a head-to-head comparison of these two tweeters? If not, then I guess the G2si would win by default, since there seems to be more positive testimonials available for that tweeter than the JP3.0?

Thanks for looking,

Saurav

 

[Saurav]

Fallen off the first page already So no one's compared these two tweeters?

 

[tiroth]

Did your budget increase?

www.e-speakers.com has the G2si on sale for $89, only $8 more than JP3. I can say that the service is absolutely top-notch, and Andre is quite nice about extra ribbons -- I'd consider them a must if you are developing a new, unproven design.

 

[Saurav]

Did your budget increase?

LOL!!! So you remembered, that's really cool Budget hasn't really increased, but eventually I'll have enough saved up to consider these, so I figured I should start my research.

The price is $79 now, which actually puts it at $2 below the JP3. So are you saying that the G2si is the better choice between the two?

 

[tiroth]

Huh, the "specials" price is more than the "regular" price now.

I wish I could say anything at all between the two in terms of sound quality, but I've never heard the JP3. I think it is clear which one I'd buy personally though based on the info available. ^_^

 

[Saurav]

Thanks. That's the way I was leaning too, but I wanted to double check, since the two seem to be so close.

 

[ThomasW]

See if either the suppliers or the mfgr's have some distortion plots or data. If they do, I think you'll find them interesting, particularly at lower frequencies.

 

[Saurav]

Wel, my current XO is at around 5kHz, and if I get these tweeters I'll probably bring that down to about 3kHz, but not any lower than that. Nevertheless, I'll look for distortion plots.

 

[tiroth]

G2, but G2si is supposed to be similar.

An externally hosted image should be here but it was not working when we last tested it.

 

[Saurav]

Yup, found that on the LSDG website. I'll be crossing this at around 3500Hz, I think, no lower than 3000Hz. If I go 2nd or 3rd order on the XO, do you think I'll be OK?

 

[ThomasW]

Although I haven't used these specific tweeters, I've been using ribbons since the early 1970's (hint think Mark Levinson's HQD)

My experience is that for longevity and 'best' performance, these smaller ribbon tweeters should be XOed around 5kHz.

So if you're going as low as 3.5kHz consider use 24dB/octave slopes. Although more costly from a raw parts standpoint, it's cheaper in the long run than buying replacement elements.

Oh, and be sure not to clip the amp!

 

[Saurav]

Thanks, that's good advice.

 

[tktran]

Someone has alluded that the JP3.0, G2si, Harwood UR2 may be in fact the same driver.

The 3 look identical...

The Aurum Cantus and Harwood has an aluminium housing whereas the Fountek has a plastic casing

 

[Saurav]

You're probably referring to this?

http://home1.stofanet.dk/troels.gravesen/Acapella project-III, LWJ version.pdf

IS the Harwood available in the USA? If not, I doubt I can get that for any cheaper than the other two.

 

[planet10]

Keep in mind that before it started being marketed as Aurum Cantus, these tweeters were called something different by each countries distributors... The Fountek i think is a different Chinese manufacturer.

dave

 

[Saurav]

Thanks. That's good to know too.

I've been reading about dispersion problems with ribbon drivers - that's only in the vertical plane, right? I would think that a narrow ribbon's horizontal dispersion should be as good as any other type of tweeter?

 

[planet10]

I've been reading about dispersion problems with ribbon drivers - that's only in the vertical plane, right? I would think that a narrow ribbon's horizontal dispersion should be as good as any other type of tweeter?

Horizontal is good, vertical gets narrower as the ribbon length increases -- so in some sense the smaller cheaper ones have an edge..

dave

 

[ThomasW]

In reality the vertical window of most of these is basically limited to a 'sweet spot' that's not much more than the height of the radiating element.

If one wants a taller sweet spot, then a line array is needed.

 

[Saurav]

I think I could handle that, that means I'll have to set things up so that the tweeter is at my listening height. That's not too hard to do. It'll mean the midrange will have to be above the tweeter though (or I could lay my HE12.1 cabinets down on their sides, but that would be strange and I haven't veneered the bottoms ). Even that can be done if I offset the midrange and tweeter laterally like I've done now, then the midrange won't be too far above the listening height. Maybe I should wait until I buy my mic before I try this. I'm pretty much just winging it now, and I have no idea what the lateral offset is doing to my horizontal lobing.

 

[tiroth]

In reality the vertical window of most of these is basically limited to a 'sweet spot' that's not much more than the height of the radiating element.

Really? Raven R2 manufacturer measurements seem to show pretty reasonable response in the first 10 degrees of vertical deflection...maybe 2dB down at 20kHz. By 15 degrees it's gone: 12dB down. Is reality much different?

Another question: I'm guessing these measurements are made from the center of the radiating element. In a line-source speaker it would probably be a lot more useful to measure deflection from the endpoints, wouldn't you think?