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

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zygadr

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1000 on: 28 May 2010, 01:53 am »
Is 550gm2 it's Density or weight per unit area?

Most materials we have been using are measured with density ratings of  ''Kgm3''

With this link, I personally can't read or understand German, so what thickness, elasticity,bending strength?

Being ''spring steel'' would suggest far too much weight wouldn't you think? :scratch:

Anyhow, see how you go, and provide some more information if you can.

The POLYSTYRENE arrives today! :thumb:...........should have the two sheets with 4 exciters per panel up and running this week end  :)

emailtooaj

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1001 on: 28 May 2010, 03:18 am »
Zygadr... Did you say you had some scrap Poly laying useless? Now that you have a new order coming in :thumb:
You HAVE to try this epoxy trick!!
My panel keeps sounding better and better every day. Which would make sense... ultra thin coats take longer to cure...my panel is on day7 of curing now.
I came home from work today, and now it sounds like I have a built in sub woofer coming from the epoxy panel :eyebrows: :green: :green: :green:
And the highs are still pumping!!
I CAN'T wait to get my new material in tomorrow!!
I'm going to do a test run on this new material, along with trying out a different mounting method that I was alluding too earlier.
If all goes well with the first 2 panels, I'll make a youtube vid on the left over panels. That way everyone can see exactly what's going on :thumb:

Maybe shut up those critics out thier!!!!!!!(I hope?) :roll:

As a side note...any thoughts on if 4 exciters place on a 16"x48" panel, in a series/parallel wiring, would be overkill? I'm using the PE $5/pr exciters.

BTW...I tested the PE $5/pr exciters and I was getting 4.5ohm out of each coil. If anyone wanted to know :?

Peace Out!!

zygadr

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1002 on: 28 May 2010, 04:21 am »
emailtooaj.....................I don't believe you.................................... ..........just kidding :green:

You MUST answer these questions though......................HAS THE POLY PANEL INCREASED IN WEIGHT???..........HAS THE EPOXY CAUSED ANY STRANGE ''WOODEN BELL'' LIKE RESONANCES?

Also, what did you thin the epoxy with?.............how many coats?............2.... was it?


I think 4 exciters is optimum for even larger panels................from my experiments so far.
« Last Edit: 28 May 2010, 07:56 am by zygadr »

panomaniac

Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1003 on: 28 May 2010, 04:56 am »
Well I went by the local big box hardware store today and looked at foam panels.
The DOW blue foam is quite stiff and dense. There was thick and thin.  There were other typical white styrofoam sheets that were much softer.

Did not have enough space to get the big 4x8" panels home, but will do soon.

zygadr

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1004 on: 28 May 2010, 07:49 am »
O.K................CAUTION!.....................after researching ''EXPANDED POLYSTYRENE''(which comes in standard ''soft'' grade and higher quality ''hard'' grade which is what I am currently experimenting with) and ''EXTRUDED POLYSTYRENE'' a.k.a. ''BLUCOR'', ''PINKCOR'', ''STYROFOAM'' made by DOW and OWEN CORNINGS,..................these are two COMPLETELY DIFFERENT products.

I have the data sheets for expanded and extruded here in front of me and they differ considerably.
Even though the ''extruded'' poly is harder and stronger, its also HEAVIER(''density'' measurement) :duh: :duh:...............nearly twice that of expanded polystyrene, and designed for a certain range of building material purposes.

Please remember this fact when you go hunting for sheets of commomly referred to ''styrofoam'' in the U.S.You may not get what you think you have got :duh:

I know this is all confusing, (confuses the hell out of me :|) but take this as an example: both EXPANDED and EXTRUDED polystyrene comes in 5 different grades in the U.S. :o

The extruded Dow stuff has a stronger compressive strength than expanded polystyrene but at a cost...........as mentioned above........................this is going backwards I'm afraid.

If I hold two identical pieces of Gatorfoam and VH grade expanded polystyrene(twice as thick), the Gatorfoam may as well be a brick in comparison!This one fact alone is why there has been a sudden and dramatic change in the performance compared to the past.
It's the one thing that makes everything else irrelevant and slides that irrelelvance towards the ''NXT modelling'' laws rather than what we are doing here.

Anyhow, besides all of the crud I just mentioned, having re-read ALL of the Podium speaker reviews(and there are quite a few :o) and reading Shelley Katz's comments between the lines and in interviews, some facts on our poor man's version are beginning to surface :wink:

The elusive ''honeycomb, mylar coated Nomex shit'' has it's problems...........don't you worry about that my little sunshines :green:...............some of the secrets and problems Katz was faced with are beginning to gel with me! :peek:...........all that stress I put up with, the wasted time and money will begin to pay off soon. :x

I now know how this technology can work for you.............not against you............the output levels, the bass, the reason for Katz's ''rounded corners'' and his problems with what to do with the edges of ''cut honeycomb panels''.

Here's a closing FACT.............I kid you not............The Podium speakers have their panels mounted directly ''inside'' the frames :roll:................I have documentation that specifically advises AGAINST that practice!..................remember............. the ''edges'' produce sound also :duh:..............now, think about that ''frame''???????

This is an incredibly complex journey in to acoustics and physics............enough to scare the crap out of anyone.....................but not me............never...............becau se we have broken the wild horse! :eyebrows:


el`Ol

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1005 on: 28 May 2010, 09:46 am »
Is 550gm2 it's Density or weight per unit area?

It's the weight per unit area. 500 g/m^2 is the usual weight per area for fullrange drivers that go up to 20 kHz.
I don't get the stuff from the manufacturer in small quantities, but there is some kind of a common internet platform for dealers and manufacturers. I'll see if I can get it soon.

panomaniac

Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1006 on: 28 May 2010, 02:19 pm »
Have you tried the denser extruded sheets?  Just wondering, as it's easy to get here in the USA.

Perhaps the foam used to make coolers is the hard grade.  At least one would hope so!

j gale

Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1007 on: 28 May 2010, 03:13 pm »
I'm playing with the denser extruded stuff. 1/2 inch 6'x2'. Initial impressions mids and highs excellent. Much louder than 2 layer cardboard. Bass is lacking compared to cardboard and gator foam. I will compare that to some 3/4" expanded [ the white stuff] If there is a harder grade of the expanded here I haven't found it. Since both extruded and expanded polystyrene are  so cheap just grab some of each and try it. I would like to see if others have the same opinion. Might try painting the white expanded with a water based spray bomb to see what that does to the sound. Something else I would like to mention is the 3M VHB tape. I used the F9473 PC (1st recommended) on several substrates and it eventually failed. The thinner F9469PC on cardboard, gator and polystyrene has never let go. It was also cheaper.

emailtooaj

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1008 on: 29 May 2010, 01:58 am »
1)You MUST answer these questions though......................HAS THE POLY PANEL INCREASED IN WEIGHT???..........HAS THE EPOXY CAUSED ANY STRANGE ''WOODEN BELL'' LIKE RESONANCES?

2)Also, what did you thin the epoxy with?.............how many coats?............2.... was it?

1)Yes, the panel has more weight to it...alot?...no....but more than I wished.
I shouldn't have put on 2 coats.
2 coats of epoxy(albeit thin) plus a 1" panel is alot of mass for only 2 exciters to vibrate, and reach dead center before the next phase. But the sound is still very very encouraging  :thumb:
As for the "Wooden Bell" sound.... I'm not exactly sure what you mean... but the closest description would be that the low end does sound very similar to a Woofer. You can hear some resonance, and after feeling around the panel, it does seem to come from the corner. My corners are squared at the moment...I'm gonna try to round them off and see if that eliminates the resonance. Any suggestions on how much to trim off???

2)I did NOT thin any of the epoxy. The epoxy mix is 1:1 ratio. I just put down a very very thin layer on my 1st coat. It was my 2nd coat that I went to heavy on.


I just got my new material in today  :thumb:
I will just put on one coat, like I was describing earlier. I think this new way to assemble the panel together will be the ticket!!
It will be a week or so before I can post the results.
Hopefully it will be well worth the wait :roll:

If not, my attic will be WELL insulated   :o :lol:

If not, I still have plan D,E,F,G and H to revert back to!! :green:

zygadr

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1009 on: 29 May 2010, 03:26 am »
jgale.................as the VH POLY is not as rigid as the cardboard or Gatorfoam, that's probably why the bass seems down.I really need to be held around it's perimeter by a wooden frame at least.

How many exciters are you using?

As I said, any coatings will affect the sound quality, but because the poly is so cheap, who cares if we stuff up.
I won't be coating with anything at this stage. Maybe some spirit based black wood stain........later on.

My panels arrived yesterday :thumb:

I too will be taking the quick and easy non-framed version to see how it sounds.
My panel is a bit larger than yours but that should not be all that significant.............we'll see what happens.

With the 9473PC tape, this is what NXT advised as the recommended tape.
It's similar to the ''rings'' supplied by NXT, but these ''rings'' have NEVER failed..........not once, so there may be some unintended misinformation here :scratch:

j gale

Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1010 on: 29 May 2010, 04:44 am »
zygadr, I'm using 4 exciters and my panels are on a wooden frame as you described yours(frame opening smaller than the panel) The extruded stuff I have is closed cell. I want to compare that to the expanded poly(the regular white stuff) Thinnest I have seen is 3/4". Painting would be mostly for appearance but given the coarseness of it I thought could help stiffen the surface as well. Have you actually compared the regular grade with the VH grade? If so can you comment on the difference in sound? I mentioned the tape so that guys would realize that even on the poly there is a tape that works. I would also like to say that I consider 2'x6' to be a minimum size. All the smaller sizes I have tried didn't begin to compare. Since the polystyrene extruded or expanded is so cheap failed experiments don't concern me. I could live with the extruded (pretty good sound) I liked the cardboard too. Point I am trying to make is that what might be classed as a failed experiment is still pretty good. For anyone sitting on the fence give this technology a try.

zygadr

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1011 on: 29 May 2010, 05:55 am »
j gale, so, your using the ''extruded stuff''..... :scratch:...................I can't really comment on this material as I went by the supplier's knowledge on the lightest and hardest poly available and was given a couple of samples of VH grade.

I would say that the softer stuff will be a bit less rigid, but would still be ultra light(even lighter in fact) which is what is creating the breakthrough in high frequencies and S.P.L..........both of which were poor in the other materials we have tried in the past.

As mentioned, expanded and extruded are two different materials with different manufacturing processes from literature and data sheet indication.

There is no doubt that coating is a definate option to be considered from here on.

emailtooaj

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1012 on: 30 May 2010, 01:50 am »
Alright, got the first coat on the panel. tap,tap, tap, tap... guess will have to wait for the verdict. :roll:

emailtooaj

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1013 on: 30 May 2010, 05:11 am »
Let me know if anyone else finds this interesting?  Might get everyone a better vision of what is going on between various materials...
http://www.ndt-ed.org/EducationResources/CommunityCollege/Ultrasonics/Physics/acousticimpedance.htm

If you understood the jaron :o  :? then check this out...
http://www.ndt-ed.org/GeneralResources/MaterialProperties/UT/ut_matlprop_plastics.htm


What I found very interesting was how similar Polystyrene and Acrylic Resin are in terms of sound travel through mediums :icon_twisted:

Zygadr... how are the new panels coming along? Correct me if I'm wrong, but you just recieved EPS Poly(expanded) in the very hard grade. Not the XPS poly(extruded)!

Peace Out!

zygadr

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1014 on: 31 May 2010, 04:19 am »
I have got the ''EXPANDED'' VERY HARD (VH) not the ''extruded'' stuff..................Gatorfoam is ''extruded''.......... :duh: :duh: :duh: :duh: :duh: :duh: :duh: :duh: :duh:

The panels have arrived and I have mounted 4 exciters per side. They are supported by some spongy foam against my horn speakers(just like the Gatorfoam in my gallery images of the past).
The VH sheets, at first, seem very flimsy and not that rigid due to their enormous size, but are stiff enough to stand upright on their own :wink:

Connecting up to system ...................T MINUS ............................last night,................... actually :green:

zygadr

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1015 on: 31 May 2010, 04:22 am »
 :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o



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 :shh: :shh: :shh: :shh: :shh: :shh: :shh: :eyebrows: :eyebrows: :eyebrows: :eyebrows: :eyebrows:
 
« Last Edit: 31 May 2010, 07:35 am by zygadr »

emailtooaj

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1016 on: 31 May 2010, 04:42 pm »
:o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o :o



[color=pink!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[color=red
 :shh: :shh: :shh: :shh: :shh: :shh: :shh: :eyebrows: :eyebrows: :eyebrows: :eyebrows: :eyebrows:


I'm assuming this is good...lol..!!!!

zygadr

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1017 on: 1 Jun 2010, 02:02 am »
 :eyebrows:

classicjt2

Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1018 on: 1 Jun 2010, 03:36 am »
I think I'm going to have to make these for myself.

James

zygadr

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #1019 on: 1 Jun 2010, 04:48 am »
I thought I'd heard it all on the Gatorfoam panel material, but on the larger sheets of poly(unmounted, so the panels buzz occasionally.......naturally........thi s may be tricky to sort out?who knows?):

SPEED OF TRANSIENTS!!!!! :o :o :o
ATTACK!!!! :o :o :o
CLARITY/TRANSPARENCY!!!!! :o :o :o
BASS!!!! :o :o :o
THOSE HIGH FREQUENCIES!!!! :o :o :o
AT LAST!.........MORE EFFICIENCY!!!! :D :D :D



 :drool: :drool: :drool: :drool: :drool: :drool:

O.k..................I know that none of you will take this seriously, but IMHO, these panels will do me for the rest of my audiophile life! :thumb: