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

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sedge

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #420 on: 18 Nov 2009, 06:29 pm »
Hello fivestring
Very interesting waterfall pics [or not, as the case may be ]?what was the distance ,I presume very close .
Small tweeters have a habit of starting and stopping very fast ,this is not how these panels work .If we think about it [as a ripple in a pond ], it makes sense .
The mic will be picking up the sound waves moving across the panel in a natural way,so its not bad ,its just doing what it does well !.
I remember reading G A Briggs book from 1956 in which he showed electrostatics out- put distortion and  delay ,that looked bad too, the poor thin film trying to move as one, but failing and ending up vibrating all over the panel.
Even so ,with all its problems, it sounds good and is regarded as the best  ?
So I don?t think we are doing too bad , do you? Any thoughts.

fivestring

Re: NXT.......rubbish??....THINK AGAIN!
« Reply #421 on: 18 Nov 2009, 07:02 pm »
BrunoB, you`re welcome and yes indeed, Gatorfoam might be much better, I`m looking forward to try one.

Hello sedge, yes the waterfalls are not very encouraging in the old fashioned way of thinking, but I can assure you even those horrible materials sound much better than a very good dome. The mic was 50cm (20" ?) away which is inappropriate for the 60x40cm panels, I guess.
You`re absolutely right, ESLs have tons of chaotic small resonances yet they manage to sound marvelous, at least to my ears.
I was just responding to BrunoB`s request to supply the waterfall measurements, but in all fairness I should measure them from a greater distance.
ESLs and planar magnetics have taught me that with this type of transducers (tall and wide) we should not put too much interest into waterfall and close miked frequency measurements, but rather to the farfield sum or even better, to the power response they project into room.
Still, any large peaks and nulls measured from a typical listening distance in the critical midhigh range should not pass without subjective consequences.
You could listen to and measure all the panels like I do, or you could do something like el`ol who selects panels based on listening only and after that proceeds with detailed mesurements to pinpoint the problems and virtues - I like that too.
In any case, with this operating principle I don`t think we`re doing bad at all, speaking of myself I`m actually highly enthusiastic about the future of NXT/DML technology.
« Last Edit: 18 Nov 2009, 10:02 pm by fivestring »

DanTheMan

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #422 on: 19 Nov 2009, 01:13 am »
Thanks for the graphs Fivestring! :thumb:  Your humble persona and contributions to this thread I assure you are appreciated by many.  They tell us more about what is going on here even if it isn't what we already know (or have been told) as good.  I think everyone that understands a little bit about loudspeakers had to know the waterfall would be ugly esp w/ mdf. :lol:  An open-minded, analytic approach is much appreciated and it may lead to a better understanding of what IS important in reproduction and what we perceive as good and natural.  Keep up the good work.  Bravo

Information is never useless,

Dan


fivestring

Re: NXT.......rubbish??....THINK AGAIN!
« Reply #423 on: 19 Nov 2009, 11:00 am »
I really appreciate the collective effort that has been taken here and am really grateful to zygadir and all the others that share their experiences about this particular speaker technology, thanks a zillion times! :beer:

As for the concrete...I will measure its philosophical content and transcendental value, instead  :lol:

captainjack115

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #424 on: 19 Nov 2009, 06:06 pm »
It only took a matter of minutes if not seconds to realize that I had a poor man's Podium producing sound that I never thought was possible in a home environment.

I wonder!!!

Has anyone here had a look at Podiums' patent claims?

I for one, have not seen their patent, but there must be some mention of NXT technology.
I don't think they can lay claim to multiple exciters, only the type and the way they're mounted. This along with the type of panel material and they way in which it's mounted. I'm sure there are other claims as to their uniqueness as a loudspeaker system. I won't speculate beyond what I've just mentioned.

My point, (yes I have one) is that anyone of us may come up with a "similar" system that may indeed have qualities worthy of enterprising commerce.
Personally, I just love the idea of making something that contains a part of my own creativity. It's sort of cool to make something that works amazingly well and knowing that the guy down the street can't walk into a store and buy one just like it.
This is the sort of thing that sets the DIY'er and entrepreneurs apart from the rest of us, we are a unique breed !

Despite having a technical background, I'm a "hands on" kind of guy.
No one here would be shocked to know that scientists and engineers the world around have made their breakthrough discoveries by empirical means.
After their discoveries are made they create formulas to fit their technology.

Please don't flame me!

"Most" of the time, technologies are a germination of an idea in which known science is applied until the desired results are obtained.
"BUT"!!!! If we get into a situation where established science is not yielding expected results, we must question our testing methods and possibly find new testing procedures.

Quite often, well heeled speaker companies have there own anechoic chambers. Not too useful below 200 hertz, so they resort to quasi-anechoic methods to try and "gate out" lower frequencies. Many times they'll make a composite curve of anechoic and quasi-anechoic results. Still not a room friendly way to test a loudspeaker.

We're pretty lucky to have NXT technology to make our own loudspeakers.
They're fairly room friendly, so there's little need to go outdoors and make measurements.

I know, I'm beginning to sound like a cheerleader for NXT. I don't have the legs for it, believe me!

I've been designing and building ESL's for over 25 years, they're great sounding speakers. The downside is getting adequate sound level and acceptable bass.
Also, they're more trouble to build. Expensive step up transformers and bias supplies, high failure rate and many amplifiers balk at driving a capacitive load.
Oh, I forgot...............No magic!

Jack

sedge

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #425 on: 19 Nov 2009, 09:03 pm »
Zygadr and fivestring.
You know that panel material I have been testing ,the one that is very rigid ,the one that got very hot but only melted the foam inside .
You will never guess  what it is made of . :oops: :roll: :duh: :lol:

j gale

Re: NXT.......rubbish??....THINK AGAIN!
« Reply #426 on: 20 Nov 2009, 01:32 am »
Yes PLEASE!!

captainjack115

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #427 on: 20 Nov 2009, 03:36 am »
It only took a matter of minutes if not seconds to realize that I had a poor man's Podium producing sound that I never thought was possible in a home environment.

Quite often, well heeled speaker companies have there own anechoic chambers. Not too useful below 200 hertz, so they resort to quasi-anechoic methods to try and "gate out" lower frequencies. Many times they'll make a composite curve of anechoic and quasi-anechoic results. Still not a room friendly way to test a loudspeaker.

Boy, pretty bad when I have to quote myself.

I meant to say that the "reflections" of the lower frequencies were gated out.

Jack

Passive Chappy

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #428 on: 20 Nov 2009, 03:57 am »
Anyone seen the following and have any thoughts on it -

http://www.nxtsound.com/index.php?id=428

Passive Chappy

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #429 on: 20 Nov 2009, 05:41 am »
Thanks for the update Zygadr.  I knew you'd be on top on this.

fivestring

Re: NXT.......rubbish??....THINK AGAIN!
« Reply #430 on: 20 Nov 2009, 10:11 am »
Zygadr and fivestring.
You know that panel material I have been testing ,the one that is very rigid ,the one that got very hot but only melted the foam inside .
You will never guess  what it is made of . :oops: :roll: :duh: :lol:

sedge, between us, I have sent you some nickels & dimes by PM (don`t tell anyone!), so hurry up man, what`s the secret material?

BowerR64

Re: NXT.......rubbish??....THINK AGAIN!
« Reply #431 on: 20 Nov 2009, 06:33 pm »
balsa

FullRangeMan

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #432 on: 21 Nov 2009, 03:37 am »
Joke

sedge

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #433 on: 21 Nov 2009, 09:56 pm »
passive chappy
was wondering if this was the same unit as used in naims ovator  s-600 speaker which I  heard at septembers hi end audio show .It xover at 300 hz to 2 x 10 ins units?which were swamping everything,had to put my ear practically on the dml to hear it .
the speaker box was very solidly built[like a brick sh*t house] but still it  sounded like a cardboard  box.
Naim what were you thinking?


sedge

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #434 on: 22 Nov 2009, 12:17 am »
Its all zygadrs fault, I was supposed to be playing with my new panels, instead I have bean trying to get ordinary foamcore to sound good .I thought I was doing quite well but still could not get over the 10 k watershed. Then zygadr says what about cardboard [concrete now cardboard what next]. Well I have had these 44 inch round cardboard panels just lying around my room for about 3 months now, very big for my room, just had not got round to chucking them out [story of my life]. :roll:
Just wanted to show that they are bad sounding, so that we can get on with finding good sounding panels. Anyway, I can?t get to the cd player because I?ve blocked off half the room with theses things, so I stand in font of them and hold the cd remote over the top of them and press play. I did not know that the track coming on next was Japanese drummers .I nearly flew out of the window! :lol: Wow the sound was big and dynamic not the cardboardy sound I was expecting, voices are good, very good. On close mic female vioces you can hear the clicking and clacking of her tongue Inside of her mouth[is this too much information ]? :scratch:
This panel is corrugated with cardboard each side, the panel is thin and quite wobbly with  the exciter about 4 inches off center,why does it sound so good?
Looking at the frequency plot it is within + or ? 3 db from 30 hz to 10 k and the rolls of smoothly,not bad!
Don`t get me wrong This is not hi end audio [its just stuck together with tape and hung in the air ]but it does draw you in to the performance so much so that you end up forgiving almost anything :drool: .
It is a mystery to me why it sounds so good?they made the foamcore sound bad ,but I am sure[I hope] we can do better.
Now were did I put those other panels?
[Well maybe I will have one more listen first?? :thumb:]

Passive Chappy

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #435 on: 22 Nov 2009, 04:50 am »
Everyone here seems to be using rectangular shapes for the panels they are using.  Could Sedge's results be due to using a round shape, which maybe approximating a point source?

And if this has some potential could adjusting the size (maybe smaller?) extend the high frequency performance?

el`Ol

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #436 on: 22 Nov 2009, 10:42 am »
I was hunting around many moons ago and found a supplier for 6mm single ply(which I think would be better?) but never got to buy or try it.

I'm not certain if it may or may not require stiffening at 6mm?.........double ply at 6mm definitely wont, but may not transfer the sound from front to back as well..............don't know unless we begin testing :scratch:

I found end grain balsa in Australia, but only from 5mm up, so no room for laminating without making it too heavy. But they have a rigid variant, maybe that's okay on its own.
http://www.balsasurfboardsriley.com.au/shop_endgrainbalsa.html

sedge

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #437 on: 22 Nov 2009, 05:10 pm »
Zygadr
The cardboard is only 3ml thick ,single corrugation sandwich type not very rigid as you can imagine.but this does not seem to harm the sound ,could it be stopping the sound bouncing around the panel[losey]?Still think they sound better from the driver side. :scratch:

Passive chappy
I hope not :duh: ,I have just bought a 120cm x 60 panel,plus I can not get to the other half of my room without moving them ,round panels take up a lot of room.
Always been told round panels are bad,but maybe offsetting the driver changes this ?
The only problem with smaller panels is you have to use a sub !

mndbndr

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #438 on: 22 Nov 2009, 07:03 pm »
Just for fun, I tried 2 exciters on a 11" x 16" 1/16" double sided copper clad.  It actually didn't sound bad compared to my 30x20 foamcore boards.  Clearly the highs are more difined.  It also seemed to perform well on the low end.  Of course, I was only using 2 exciters on a small surface, so the lows rolled off high.  The the SPL was not on par with my foamcore with 4 exciters of course, but I think a larger board with 2 more might have potential.  I might try to find a bigger clad board to play with.

Brian

mndbndr

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Re: NXT.......rubbish??....THINK AGAIN!
« Reply #439 on: 22 Nov 2009, 07:16 pm »
It looks like it is readily available in 36"x48" sheets.  Around 100 dollars US.

I was a little worried about the magnetic effects of the copper.  Didn't seem to make any difference in the smaller panel.