NXT.......rubbish??....THINK AGAIN!

captainjack115 · « **Reply #580 on:** 26 Dec 2009, 05:43 pm »

Quote from: zobsky on 26 Dec 2009, 04:19 am

Does the tacky tape mentioned inthis thread cure rigid or is it permanently supple. I'd think the ideal adhesive should tend towards rigid ( not completely though) in order to facilitate efficient energy transfer to the panel

The Tacky Tape remains sticky to the touch after it's been exposed to the air. Instructions urge using it right away after peeling protective coating to start the curing process. So, I guess it never gets rigid, but holds on for dear life after curing.
I've also used Super Glue gel which does get rigid. I hear nor measure any difference from the tape and glue. I cannot say that the Tacky Tape is comparable in quality to the 3M tape Ziggy uses. It may be something else entirely, or in fact the same 3M tape under license. I can only speak from personal experience, it holds very well and for some people, easy to purchase.

Jack

zobsky · « **Reply #581 on:** 26 Dec 2009, 08:25 pm »

Thanks, I bought some of the tacky tape this morning and am going to stick 8 buyout 4 ohm exciters per 2 x 6 panel ( wired for 8 ohm to ease the load on the amp and also hopefully increase the effective damping factor)

captainjack115 · « **Reply #582 on:** 27 Dec 2009, 01:15 am »

Quote from: zobsky on 26 Dec 2009, 08:25 pm

Thanks, I bought some of the tacky tape this morning and am going to stick 8 buyout 4 ohm exciters per 2 x 6 panel ( wired for 8 ohm to ease the load on the amp and also hopefully increase the effective damping factor)

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Sure would appreciate a report on the results.

My panel has 8 exciters at 8 ohms, but it's only 20 X 30 inches. Sensitivity is excellent and volume peaks were over 106 db at 16 feet away. Loud, very loud!!!!!

Jack

DanTheMan · « **Reply #583 on:** 27 Dec 2009, 01:30 am »

Has anyone floated a panel inside of an inner tube for a bicycle tire? You gould pump it up enough to float the panel w/o minimally restricting the edge. It seems that might be a decent way to get a "floating" panel that doesn't sag. Then with a spine and a frame you could keep the VCs from sagging. Also, has anyone tried a horizontal alignment of the exciters? That might provide better directivity for that camp of thinkers.

Just some thoughts,

Dan

captainjack115 · « **Reply #584 on:** 27 Dec 2009, 03:41 am »

Quote from: DanTheMan on 27 Dec 2009, 01:30 am

Has anyone floated a panel inside of an inner tube for a bicycle tire?

My panels are floating in rubber bands. Not ideal as they have stretched and sagged.
I think floating is a good way to go though.

Jack

zobsky · « **Reply #585 on:** 27 Dec 2009, 05:53 pm »

Quote from: captainjack115 on 27 Dec 2009, 01:15 am

Sure would appreciate a report on the results.

My panel has 8 exciters at 8 ohms, but it's only 20 X 30 inches. Sensitivity is excellent and volume peaks were over 106 db at 16 feet away. Loud, very loud!!!!!

Jack

Well, the (1") tacky tape worked well, so far (I had one instance of an exciter coming partially unglued after a few hours, I've re-taped it and am going to evaluate over time). Thanks for the heads up

Well, I couldn't make an apples to apples comparison as I only had one or two drivers on my smaller ( 24 " x 48") panel vs 8 on the larger panel but that said,

1. the larger panel had more bass and was (obviously) more efficient.
2. The smaller panel might have just a little more detail but (1) more than makes up for that. You will understand that I just have one of each panel running at this time so I can't make a thorough analysis, ... YET

The results of another test may explain why some of you have no highs in your experiments. Using generic double sided FOAM tape killed high frequency reproduction. I mean, cymbals were totally MIA. OTOH, using the tacky tape (or possibly any other THIN / non foam based double sided tape) brought the treble back. I can hear till about 16 KHz and heard treble at that point though it possibly wasn't as extended as some speakers I've heard in the past. In other words, the treble could use some more extension, but its not a deal killer at this point.

I'll have to run some sweeps over the next week or so, but just listening to music and WinISD generated test tones in room, the larger panel is strong to at least 70 Hz with output down to 50 Hz. That said, in practice, it manages to reproduce kick drum and bass well, and as such can be used without sub-woofer augmentation for jazz and maybe even some rock / pop music. Falls flat on its face with hip hop and some electronic music, depending on the type of bass line.

The good: music sounds "correct", so far. I'll post more once I have both panels running.

Regarding mounting, I'm wondering if I could "clasp" the panel left and right edges around the midpoint i.e. around the 3 ft point of a 6 ft panel (rather than at the top ( 6ft) and bottom (o ft) )and minimize the effects of mounting on the panel performance. Need to find a volunteer.
More later

j gale · « **Reply #586 on:** 28 Dec 2009, 01:14 am »

I had 2'x6' black gatorfoam panels and was happy. Because white gator is a little different (harder surface) I decided to try it. This time I built a frame 2"x3/4. I have the buyout exciters (which I have been very happy with) I mounted the exciters by drilling a 1and 3/8" hole deep enough to take the magnet ( about 3/8") I drilled a small hole the rest of the way because the exciter has a vent hole through the magnet. A couple of dabs of silicone hold the exciters in place. The panel is 1/4 " smaller than the inside of the frame and ends up just about flush with front of the frame. I think the exciter can easily accommodate the weight of the panel but sides need to be supported or the panel can move too much like pivoting on a knife edge putting too much stress on the spiders. I solved this by gluing 4 of those synthetic Australian wine corks to the inside edge of the frame (2 on each side about 2' apart but not directly opposite of one another) Bass hasn't suffered at all. It's just as good as without the corks. I thought of doing it with styrofoam backer rod that concrete places and building supply places have. Might still try it since that would allow more movement. The white seems to have better tone than the black. I don't know if the spine or the material is responsible for the improvement. What I ended up with looks just like podiums model one. I rounded off the corners and I believe that that also improves the sound.

el`Ol · « **Reply #587 on:** 28 Dec 2009, 09:33 am »

Quote from: irishpatrick33 on 24 Dec 2009, 03:40 am

And has anybody tried a more permanent solution, like superglue for instance?

Lots of reading stuff.
http://www.loctite.sg/sea/content_data/LT3273_Speaker_Assembly_Adhesives_Guide.pdf

el`Ol · « **Reply #588 on:** 28 Dec 2009, 01:05 pm »

Holy...
Found the rubber-cyanacrylate in an online store:
"1 KG entspricht 1497,50 EUR"

usp1 · « **Reply #589 on:** 28 Dec 2009, 02:19 pm »

Quote from: zobsky on 27 Dec 2009, 05:53 pm

The results of another test may explain why some of you have no highs in your experiments. Using generic double sided FOAM tape killed high frequency reproduction. I mean, cymbals were totally MIA. OTOH, using the tacky tape (or possibly any other THIN / non foam based double sided tape) brought the treble back.

I have the white gator foam and am using the 3M tape that zygadr recommended and yet I am not able to get the highs! Not sure why?

zobsky · « **Reply #590 on:** 28 Dec 2009, 02:50 pm »

I haven't used the 3M tape but when experimenting with somewhat spongy double sided tape, the highs were totally gone , absorbed by the tape

OTOH, The tacky tape I used is paper thin. Do you have access to this stuff? It's fairly inexpensive

That said, the highs are not ribbon like extended, but they aren't overly rolled off like in my earlier experiments

I wouldn't mind mailing you a piece of it but it'll probably cure while in the mail

j gale · « **Reply #591 on:** 28 Dec 2009, 04:03 pm »

Zygadr, I think I do have white gator. The foam core is white. The gatorfoam tech bulletin states (under the photo mounting heading) "the white face has a harder surface." That being said the improvement could be from exciters mounted on a spine,rounded corners, or maybe even the artificial corks acting as sound bridges.

They also recommend the white for outdoor use but not the black. I see comments about a lack of highs. I have not experienced that with either colour. I used the 3M tape which is very thin and wonder if Zobsky has correctly identified the problem some have with a lack of highs. Will experiment with a couple of piezos later to see what that adds

j gale · « **Reply #592 on:** 28 Dec 2009, 04:27 pm »

Another thought on the complaint about a lack of highs. I'm beginning to wonder if some are looking for the tizzy unnatural stuff that some speakers put out. My panels do very well with cymbals, triangles etc. clear, no hiss or tizz just sounds real.

zobsky · « **Reply #593 on:** 28 Dec 2009, 04:28 pm »

Quote from: j gale on 28 Dec 2009, 04:27 pm

Another thought on the complaint about a lack of highs. I'm beginning to wonder if some are looking for the tizzy unnatural stuff that some speakers put out. My panels do very well with cymbals, triangles etc. clear, no hiss or tizz just sounds real.

+1

usp1 · « **Reply #594 on:** 28 Dec 2009, 04:44 pm »

I ran test tones to check the highs. My regular speakers are able to produce the test tones but the panels are not. I can neither hear the test tones nor detect them with an spl meter when using the panels. The difference in the highs is noticeable although not dramatic.

As for the tape I used the expensive 3M tape that zygadr recommended. Prior to that I was using a thinner cheaper 2-sided clear (non-foam) tape. In both cases the highs were missing. Having said that I find that I get highs up to about 15 Khz with 2 exciters. Lower with more exciters.

zobsky · « **Reply #595 on:** 28 Dec 2009, 06:15 pm »

Strange, .. These speakers aren't sparkly bright but they aren't excessively rolled off either. Time for measurements, comparisons and to bring in some other listeners.

1.What are the speakers you're comparing to
2. what impedance are your panels
3. how did you wire your exciters (what series / parallel combination)

DanTheMan · « **Reply #596 on:** 30 Dec 2009, 05:18 am »

Ziggy, before you throw in the towel, try mounting them on a spine and then float them on an inner tube for a tire pumped up to a known pressure and keep it there. It seems to me that this should prevent these issues from occurring if that are all built onto one frame and stabilized. I would think the tire(s) should be somewhere around 3/4 of the way full. I hope what I just wrote made sense. Did it?

Dan

j gale · « **Reply #597 on:** 30 Dec 2009, 06:07 am »

I have a set of 2'x6' panels configured the same as Zygadr 8 exciters. I have another pair mounted in a frame with 8 exciters on a spine same size.I used 1" diameter styrofoam backer rod 1" long cut in half length wise so flat side glued to panel and end to frame with weldbond. I used 3 on each side randomly placed. Seems to hold panel well and because only half as thick in the front back plane allows some movement. No loss of bass. It actually is better. I hope this arrangement keeps things in line. Even if the exciters had to be replaced every year it would not be a deal breaker for me. At $20 per panel for exciters I'm not too worried. Having some support on the sides as Podium does it hasn't cost any of the magic or performance. New models of exciters are appearing. I'm sure that if ours are too flimsy that will be overcome. My 2 for $5 look pretty sturdy. These sound too good to give up on.

el`Ol · « **Reply #598 on:** 30 Dec 2009, 08:53 am »

On 6moons one can read that Shelley Katz could only find one company in Europe that could manufacture the panels according to his specs, which I first couldn't believe. But recently I read on a manucurer's site that the flatness is +/- 5 mm on 2.4 m. This would make manual adjustment necessary when mounting the exciters on a spine. Maybe this is the problem. I wonder how the situation is for the Alcan Composite stuff.

Eagerly awaiting my Lamera Hybrix sample

mkstat · « **Reply #599 on:** 30 Dec 2009, 10:00 am »

Quote from: zygadr on 30 Dec 2009, 03:30 am

...........The panels have, over the last week, despite numerous checks, LOST SENSITIVITY !!!!!!!!!!!!!

....I have inverted my panels a few times and heard the distortion dissapear, but the recent development in output loss can not be rectified as easily.

Where to go from here?...........don't know

You could try to recover the suspension stiffness by applying a little (!) thinned (with metanol or ethanol) epoxy resin with a paint brush. This will of course shift the resonance frequency up, but also recover efficiency. It will be difficult to achieve repeatable results.

Around the panels` fundamental resonance frequency (f0) the exciters` excursion will be very high (maybe exceeding x-max -> distortion) and this will harm the suspension the most. You are useing very big panels where f0 is quite low - you could set a highpass filter and your exciters will live much longer and you presumably will still have a full range design.

-m