Gemme Audio VFlex magic

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PA5cAL1

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#1
I was just looking around the other day and found one very interesting looking speaker, the Vivace V2 from Gemme Audio. Gemme Audio has done some very bold claims, according to them, the Vivace V2 can play down to as low as 20Hz with just a little Fostex FE108E 4" Fullrange driver. And according to a few reviewers out there, they actually do. 6moons audio reviews: Gemme Audio Vivace

My question right now: how have they done it? Gemme audio themselves is talking about a technology called vflex. Is that something we should take with a grain of salt? They're not really explaining how it exactly works. Gemme Audio: "This revolutionary acoustic loading technology operates by accurately controlling cone movements and accelerating air motion, much like a turbo charger in a car engine." also: "This loudspeaker construction technology defies the very laws of physics by extending low frequency reproduction below the human hearing threshold of 20Hz... using a single 4" driver."

Well that is quite a bold statement, saying that you can defy the laws of physics. I guess, almost every speaker enclosure works a bit like a turbo charger than. I have only been able to find one picture showing a part of the inside of the enclosure but it doesn't give us a lot of information.

TANTO-Bubinga2.png


From what I can make out, it is something like a mass loaded transmission line but more horn shaped. They're using a less than ideal shaped transmission line for the low end, and they've added a bass reflex pipe to it as a bandpass to filter out all of the unwanted rumble. What are your thoughts on this one?
 

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#2
It's a mass loaded back-horn. No magic, mystery, or anything else. Descended from when things went rather pear-shaped with the 'First Horn' product from their (also defunct) Atelier Audio concern. Said 'First Horn' got roasted by the 6moons reviewer for functioning over too wide a BW, i.e. they let the horn run up a long way into the midband, which is rarely a good idea. They came up with a modification where they slapped a plate with a hole in it over the terminus, creating a reasonable low-pass filter & in the process mass-loading the horn somewhat. From the reviewer's comments, it worked (I did a couple of quick & dirty models of it at the time, confirming), though a rather gimcrack piece of product development. Since the principle is perfectly valid (though it doesn't offer much in my experience that you can't get from rather more simple cabinet types / configurations) they evidently decided to run with it with Gemme -it does lend itself to fancy advertising copy. Claiming 'defies the laws of physics' is at best daft though. Mind you, a lot of gullible types out there who actually believe such statements. Not helped by the fact that some magazines actually repeat advertising copy in their reviews verbatim, and don't always mention the fact that that is where they got it from.

Winning a lot of friends with that, aren't I? 😉
 
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#3
we wouldn't have you any other way Scott - you know the old Jack Nicholson line
"Truth?, you can't handle the truth"


I almost called you "professor" - ask Dave privately why I decided against that 😀


as to the actual speaker enclosure in question - two things:

didn't Bernie Foucher have a pair of those at one time - pretty enough things as I recall, and sounded fine but "defy the laws of physics" no they did not

other than transient curiosity as to how someone might actually obfuscate over such arcane & dubious technology that they are ill-prepared to disclose (don't open the curtain Dorothy), how much oxygen and bandwidth do we want to expend in contemplation thereof?

oops, what am I thinking, this is DIY - no such thing as pointless discussion

- your friend, lieutenant snark
 
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#5
basically, 20hz, sure- at -30dB and 70% THD. Squeezing deep bass from a 4" is a fools errand, the acoustic contortions required are much worse than the damage from that evil crossover at 200hz. There's plenty of cabinet volume to do a pair of opposed 10"s or 12"s, floor loaded, with a 200hz XO.
 
#6
chrisb said:
didn't Bernie Foucher have a pair of those at one time
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Yes. Our 1st meet with Bernie was the Sunday of a diyFEST and he brought his Gemmes. No way do they do 20 Hz.

We swapped in a set of treated FE108eS which made an improvement, While the driver was out we explored the cab as much as possible without sawing it in half. As best we could tell it was simplier, only 1 internal panel, and more complex, holes in the internal panel, than the visualization in Post #1. I never got excited enuff to draw up the sketch (which is likely stillin the "archives".

Since then Bernie has/still has a number of speakers he prefers, including Victor with FE166eSR, and a number of Mark Audio boxes, including his current Mar-Kel70mT with specially treated EL70eN. Now if you want a 4" with bass, these get into the low 40s.

dave
 
#8
It would be good to see what the HD is at 20 Hz. What I find interesting is that the 6moons reviews never make a measurement. I guess it is harder to paint things in glowing colors if data says otherwise. I don't doubt that you can get 20 Hz from a 4 inch full range driver. I accidentally got 30 Hz from a 3.5 inch Vifa in a AMLTL, albeit at -12 dB below the main. But the HD was almost 100%.
 
#9
The gemme went out of business but the owner has started another company called arteluthe. He has come out with the same type of speaker but is now powered. He has posted the internals do the speaker which looks like the modified atelier first horn. If you google arteluthe, you'll find exploded pictures of the speaker.
 
#15
planet10 said:
An externally hosted image should be here but it was not working when we last tested it.


dave
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That's the one, I had a atelier first horn and did the modification myself with instructions from the designer. It did work, it reach low but, not 20hz. There were dips in the mid bass. The speaker in the picture seem to have the same geometry except it is taller. So basically the speaker chamber is connected to a larger chamber by an expanding port and the larger chamber is mass loaded. The one panel in the middle of the large chamber looks like a brace to stiffen the walls of the larger chamber. That was the same for the atelier first horn. I have been thinking of trying it on my lowthers ex3.
 
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#16
Oh dearie me. I'd hoped they'd actually progressed from the First Horn configuration.

It's still a (mass loaded) horn since it expands toward the terminus, albeit in an inconsistent fashion.

Your EX3s? I'd think long & hard. They may not excite the line sufficiently with that cover over the back (I believe Bob Brines found this when trying EXs in MLTLs -ended up needing to remove it), and don't forget Lowthers will need help over a rather wider BW than the drivers employed by Gemme / Arteluthe.
 
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#17
Your EX3s? I'd think long & hard. They may not excite the line sufficiently with that cover over the back (I believe Bob Brines found this when trying EXs in MLTLs -ended up needing to remove it), and don't forget Lowthers will need help over a rather wider BW than the drivers employed by Gemme / Arteluthe.
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I have been thinking about what your saying. I put a pair of fe108 ez in to a pair of alerion BLH and I get louder or more fuller bass from the 108 than the dx45 that I had in the alerion. The 108 were used in the gemme vivace. I have the ex3 in a pair of fidelio now and I have read the someone fitted the fidelio with fe166e and the combo produced more bass than the dx3 that he had in them. I modeled the plans for the enclosure but hesitated in building them based on this info. I asked the designer a while back if the enclosure would work with lowthers but never got an answer. So what I get from this is that to get decent bass out of the lowthers is the big fun horn which is too big for my room.
 
#18
Yes & no. Actually, based on Lowther's published data (assuming it's accurate) the EX3 isn't as bad as all that, at least in terms of mass-corner. It's substantially lower than that of the 108. However, I am slightly sceptical about the data, and Lowthers often have a... what's the word? 'vivid' balance with a substantial lift up to about 10KHz. In itself this will tend to make the LF seem somewhat weak, and there's not all that much you can do about it with a cabinet alone. A big horn helps, but back horns are only useful up to the mass corner (and sometimes not even that -depends on how low it is) once amplifier output impedance, wire resistivity &c. are accounted for & can't help with the rest. This is part of the Lowther sound some love & some hate -in your case it sounds like you prefer something that has a somewhat flatter FR.
 
#19
Scottmoose said:
Yes & no. Actually, based on Lowther's published data (assuming it's accurate) the EX3 isn't as bad as all that, at least in terms of mass-corner. It's substantially lower than that of the 108. However, I am slightly sceptical about the data, and Lowthers often have a... what's the word? 'vivid' balance with a substantial lift up to about 10KHz. In itself this will tend to make the LF seem somewhat weak, and there's not all that much you can do about it with a cabinet alone. A big horn helps, but back horns are only useful up to the mass corner (and sometimes not even that -depends on how low it is) once amplifier output impedance, wire resistivity &c. are accounted for & can't help with the rest. This is part of the Lowther sound some love & some hate -in your case it sounds like you prefer something that has a somewhat flatter FR.
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Flatter fr is not the most important to me, the clarity and the speed of the ex3 is what really attracted me. I run a sub with the fidelios. I find that those traits about the lowthers very addictive. Right now I'm using the fe108ez in the alerion BLH with no sub and is very satisfiying. I may switch to SS amp for them, my SET 45 will drive them loud but I feel it needs more power than the 1.25 watts that I'm them now.
 
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