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(4) Sealed 21": Funk Audio UH-21v1

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Funk Audio    38

So due to the confusion that seems to be happening with the GUJV1 motor being a Focusworks Audio product, and the GUJV2 being Funk Audio, we have decided we should rename it before putting it up for sale. What does everyone think of; UHFA(driver size) Mk1?, (under hung funk audio, mark one).

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Funk Audio    38

WOW thats a lot of letters. BUT doesnt bother me which you decide. I will most likely just call it the UH18 or 21 for short..

We are open to suggestions, UH21 Mk1 could work.

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dgage    67

So due to the confusion that seems to be happening with the GUJV1 motor being a Focusworks Audio product, and the GUJV2 being Funk Audio, we have decided we should rename it before putting it up for sale. What does everyone think of; UHFA(driver size) Mk1?, (under hung funk audio, mark one).

 

I concur with the UH21 as the FA in the model would be redundant since it will often be referred to as the Funk Audio UH21, Funk UH21, FA UH21, or simply UH21, which is great if it becomes so well-known that UH-21 is all that is needed.

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Ricci    652

Edit: I just looked at the M.A.U.L. CEA results and distortion data, and it looks like the thing may still be a long way from excursion limits when the amp taps out at 30 Hz.  The distortion is a bit high there, but that is most likely because of the high acoustic amplification of the 2nd and 3rd harmonic from the horn loading.  So it might sound fine with 125 dB @ 30 Hz @ 2m GP.  Nevertheless, if one were to upgrade the amp and wanted to get every last dB out of the thing, the IMD problem could prove to be the biggest issue.  (It's also possible that IMD from the driver itself could be a major problem, for example if inductance is especially non-linear in stroke or current).

 

That's correct. The drivers are not near xmax in the bandwidth when the amp runs out.

THD high? It's under 12% from 13-94Hz during the loudest sweep and that's with the amp giving out and the loading of the upper bandwidth boosting some of the THD harmonics. In band excursion max should be near 21-23Hz. Consider the output levels during this as well. Once you drop the output back 5-10dB the THD drops well down. Actually it's one of the more natural and cleaner bass systems I've heard due to the extremely low distortion and huge headroom. Very little driver excursion is used. The problems with it's performance and sound happen up above 90Hz and it's not really meant to be used that high so I consider that stuff out of band. I tried it run up to 120Hz or so and I just couldn't get it to behave. It gets wonky if it isn't low passed and equalized correctly. 

 

Those drivers are some of the best air pumps with regard to inductance variation versus stroke,due to the coil arrangement and motor design. 

 

I'd worry more about the structural integrity of some areas in the cab rather than IMD. The compression ratio and air speeds in the slot/horns is not very much comparatively and the driver excursion isn't much unless driving the hell out of it near 20-30Hz. 

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SME    211

That's correct. The drivers are not near xmax in the bandwidth when the amp runs out.

THD high? It's under 12% from 13-94Hz during the loudest sweep and that's with the amp giving out and the loading of the upper bandwidth boosting some of the THD harmonics. In band excursion max should be near 21-23Hz. Consider the output levels during this as well. Once you drop the output back 5-10dB the THD drops well down. Actually it's one of the more natural and cleaner bass systems I've heard due to the extremely low distortion and huge headroom. Very little driver excursion is used. The problems with it's performance and sound happen up above 90Hz and it's not really meant to be used that high so I consider that stuff out of band. I tried it run up to 120Hz or so and I just couldn't get it to behave. It gets wonky if it isn't low passed and equalized correctly. 

 

Those drivers are some of the best air pumps with regard to inductance variation versus stroke,due to the coil arrangement and motor design. 

 

I'd worry more about the structural integrity of some areas in the cab rather than IMD. The compression ratio and air speeds in the slot/horns is not very much comparatively and the driver excursion isn't much unless driving the hell out of it near 20-30Hz. 

 

Yeah.  It's funny how most distortion problems go away when you add more drivers.  :)

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chrapladm    46

Well BC prices seem to have just sky rocketed for me now so I am very interested in hearing more about these 21's and their 18" brothers.

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SME    211

The drivers came in yesterday.  I updated the first post with pictures and some specs.

 

The free air tests impressed me.  I didn't get any precise excursion measurements, but these can move some serious air.  There was a point at which the driver looked utterly violent, compelling me to take a few steps back, yet all I could hear was the swisha-swisha sound of air being forced through the vents.  I think I might have been at around 2.5" peak-to-peak at that point, but I did not have a good visual reference.  Distortion grew gradually with each 0.5 dB click above that, and I didn't go much farther so as not to put too much heat into it with low frequency sine waves.  I was pushing up to around 1 kW, depending on frequency, but FWIW, the magnet/motor housing was still cold after the tests.

 

The other remarkable thing is how light they are.  Yeah, they are something like 45 lbs, but considering the size, it doesn't feel like much.

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chrapladm    46

Just so I understand this correctly, does the UH21 have a 30mm Xmax?

 

The UH21 looks very similar to the SW152 in a 200 liter cabinet with double the voltage.(response shape wise) That pushes it to about 31mm with 1050watts. Does a little better down low than the SW152 but just a touch. Happy to see it does look good in a few of the horn designs I have. AND I LOVE THAT CONE. :D

 

AND did you say 4.5cuft for the pair of 21's? AND do you have any more pics of the cone?

 

Curious if that is like the Aura 18's cone or just the picture.

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Funk Audio    38

I believe he said 4.5 per driver.

 

Are you talking in sim land?  :rolleyes:. Real world is a little different sometimes.

 

Based on our in house tests compared to the 21.0, the UH21 given the same power in the same box ~3 cubic feet internal, the long term output sweep was about 1-2db lower across the board, although distortion under 60hz was a little better. Throw it in about 7 cubic feet and long term sweep output was 1-2 db higher than the 21.0 under 50hz, along with much lower distortion. In 4.5 it should be fairly close to that, as 7 is too big, didn't actually take much power in the low end. So overall long term output in 4.5 cubic feet should be similar to the GUJ21v1 as tested 20hz down(but with much lower distortion), about halfway between the GUJ21v1 and the 21.0 20-40hz about the same as the 21.0 50-60hz, and a couple db below the 21.0 above 60hz.

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SME    211

Just so I understand this correctly, does the UH21 have a 30mm Xmax?

 

The UH21 looks very similar to the SW152 in a 200 liter cabinet with double the voltage.(response shape wise) That pushes it to about 31mm with 1050watts. Does a little better down low than the SW152 but just a touch. Happy to see it does look good in a few of the horn designs I have. AND I LOVE THAT CONE. :D

 

AND did you say 4.5cuft for the pair of 21's? AND do you have any more pics of the cone?

 

Curious if that is like the Aura 18's cone or just the picture.

 

I'm going to try to give them 4.5 cuft per driver.  I don't think I have been given an official manufacturers "Xmax" figure, but 30 mm is probably a good guess, similar to the Focusworks 21GUJV1.  Xmech, I believe, is closer to 40 mm.

 

I can take more pictures of the cone for you.  What is it you'd like to see?  Any particular angle?  The appearance changes depending on which way you look at it.

 

As for comparison to the Aura 18 cone, I haven't seen an Aura 18, but it looks like that driver uses a brushed aluminum cone.  The dust caps may be similar, but the carbon fiber looks completely different.

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chrapladm    46

Thanks Nathan for the info. I was referring to simulation. When looking at only that they had similar response shapes. But obviously with 30mm excursion there not going to compare for long when at burst mode. I only have simulations to go by for now so thats why I had asked.

 

SME, I believe the dustcap on the Aura 18 has a point and is an actual cone shape. Normally you would have a round dome shape or inverted shape. So when it was hard to tell from the pictures I was curious if it was like the Aura dustcap and coming to a point.

 

Its not a big deal either way just curious is all.

 

Here in this pic you can see the dust cap shape better:

269-186_HR_0.jpg

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SME    211

I didn't realize that Aura driver dust cap had a point like that.  The dust-cap on the UH-21v1 is inverted and has very slight curvature.  It is aluminum, subtly brushed in a pleasing radial pattern.  My picture isn't very good, but if you look closely it has a diffraction pattern kind of like a compact disc.  :)

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Ricci    652

Good looking drivers. Should be performers. Underhung drivers with 350 normalized motor force. LOL. :D

 

Nathan this is a bit off topic but did you start dressing the tinsel leads on the drivers using the CF cones? Just wondering.

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Funk Audio    38

Good looking drivers. Should be performers. Underhung drivers with 350 normalized motor force. LOL. :D

 

Nathan this is a bit off topic but did you start dressing the tinsel leads on the drivers using the CF cones? Just wondering.

Yes we are now using a high end 3M shrink tube over the whole lead wire, and I am really happy with how they are working, So far in testing they seem to be immune from any possible "flapping"(and subsequent touching of the cone as a result) as can be an issue at certain frequencies when they are long enough to accommodate these excursion levels. And I have never liked leads sewn into the spider.

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Kyle    62

Good looking drivers. Should be performers. Underhung drivers with 350 normalized motor force. LOL. :D

 

Nathan this is a bit off topic but did you start dressing the tinsel leads on the drivers using the CF cones? Just wondering.

Yes, tis a lot, probably the most out of any production uh driver ever.

 

its got some neo I hear :)

 

The hard part is doing that with a 2 layer coil (or 4-layer flat) which I'm guesing this driver is?

 

Some fun facts

 

Double the turns on the coil doubles the BL^2/Re

Doubling the diameter of the voice coil  (and maintaining the same B Flux, e.g. increasing the magnet to accommodate the larger flux gap area) will also only double the BL^2/Re.

Doubling the B will quadruple the BL^2/Re and also no increase to inductance like the other two. Magnets are by far a motors greatest asset.

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SME    211
its got some neo I hear :)

 

Just a bit.  :)

 

 

I have to admit that the appearance of the woven carbon fiber is growing on me.  As I've said, the pictures don't really show it.

 

Something surprising is how, after having them only a short while, they don't actually look so big.   I'm not sure how that makes sense, but especially when I visualize them installed in the cabinets I'm designing, the impression I get is that they will appear quite compact.  They will also help the 12" in my mains look more like the mid drivers that they are.  ;)

 

I'm iterating through designs to try to get a solidly braced enclosure with minimum material use.  I'm hopeful I can get the final weight down to 175 lbs, maybe, but we'll see.  I'm also stalled because the trim rings I bought for them fit just a bit too close to the surrounds.  I want to resolve that issue before I finalize my design and start building.  Once that's done, I'll be ready to roll.

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SME    211

And 8's look like tweeters.

 

Heh.  Such whimpy tweeters.  My horns are 15" wide:

 

post-1549-0-92873400-1474405503_thumb.jpg

 

 

Edit: Just to note, these subs will be going on each side of the rack, occupying the space currently taken up by the two Hsu Research subs (different models) and the tables that the front left/right sit on.  I may go a tad taller than the racks are (23 inches) but not by very much as I plan to use a retractable AT screen right in front of the TV and center channel and hope to be able to drop it as low as possible.

Edited by SME

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