[BowerR64]

If this is in fact a  ''HOLE''.............it may be NXT's suggestion to TDK to squeeze some more high frequencies from the exciter's voice coil?

Thats what i wanted to do, i noticed when i ordered mine there was 2 wired together in series. I thought maybe i could mount one down low and one up high and then cut a hole in the foam board near or in the center of the top one to maybe act as a tweeter or a midrange and then maybe the bottom one would cover the low end.

That smokinjoe guy used the metal on the back of his i figured that helped the high end but i wondered if it was more open so the metal was more exsposed if it may ring out similar to a metal type tweeter.

I might try a hole, some slots or even half and half, top half exsposed metal and the bottom foam board and see wich gives the better sound to my ear. I thought ide get them monday but maybe today?

[jeffac]

And a couple more possible panel materials 

ALUCORE? lightweight aluminium honeycomb panels - look interesting especially for HF
http://www.alucobond.com.au/files/AFYW464EUS/ALUCORE_Product_Info.pdf

BioBoard? hard surface lightweight cardboard core panels
http://www.lairdplastics.com/content/view/495/

cheers .. jeffac

[sedge]

Zygadr
I too am guilty of being the shifty man walking around musicians. Last month my wife and I went on a 9 mile walk with friends through the lovely English countryside, we came across a 9th century church, inside there was a string quartet practising .
The sound was wonderful ,I pretended to walk around looking at the beautiful little church ,but really I was moving from side to side  and to the back as you did ,listening to the sound  while thinking to myself this is the sound I like and this is the sound I want.I have come close but there has always been problems of one sort or other.
My wife and friends left ,and eventually I had to leave to join the walk .this was the best part of the day for me and I wished I could of stayed longer.
This also brings me on to your comments on live music which are quite true except  for certain exceptions such as large church or concert organs  or Japanese drums,you yourself mentioned a band marching past banging the drum  that you could feel [this is probably the slam sound I was trying to explain ].
There is also that dreaded close microphone technique .I do have some cello music with this technique ,You can hear the bow rasp and the clicking of his fingers also his breath which sounds almost as passionate as the music.
When he plays low notes the room shakes ,the microphone is so close that you literally do have your ear not tongue in the musicians ?f hole?[I do hope this isn?t  rude ].
This is obviously wrong, as you would not hear it sitting in the 10th row of the theatre.
But it sounds soooooo good even though it is overblown.
Classical guitarists also use this to good effect by banging and tapping on their very dynamic  7ft long guitars.
I suppose that in the end I just want to play all types of of music,a bit of everything ,but it must sound good! and move me emotionally.

[BowerR64]

You know how home theater is 5.1 and each channel is dedicated. Why cant they do this with music and dedicate certin channels to certin speaker types?

You could use panels for one type of sound, Horns for another, bass shaker, traditional speakers have the sound more seperated and only play threw a speaker type that it sounds the best on.

I noticed some one a few pages back posted pictures of their panels, in the background they had these large horn looking things. Reminded me of a tuba or somthing. Does this type of horn play certin types of music better then others?

[BowerR64]

I thought when you run 2 speakers in series it raises the ohms and in parallel it lowers the ohms?

Why are the NXT drivers both 4ohm and they are wired in series yet they read 4 ohms?

[usp1]

Its 4 ohms per driver. so in series they are 8 ohms.

[sedge]

So, its official, the hunt is on for a better panel material.
I still think that using  different  types of material [ali,bolsa,]with a foam type core could work well [need to try it with a large panel].This has been put on hold for a while because when my friend came round he said he preferred the sound of my experimental foamed core panel I was trying out [this is the panel that the over heated exciter melted].Only one exciter was used; but  it was a larger panel , so I will have to go and get a second panel for stereo ,the panel is 4x2ft[I think this is the largest size they make ] and I actually paid money for it [?16] .I got a little excited in the diy shop when I found it,because when I scratched the back of the panel the sound came out from the front so loud and clear,just like a paper coned speaker.At the time I only bought  the one as I did not know if having a panel that sounded like a cone speaker was a good idea,could just be more trouble ?
I will use 4 exciters per panel and will let you know if it is any good, if not my friend is going to get huge amounts of earache,but hey what are friends for?.      
 

[BowerR64]

Ive read many people say that 2 drivers running out of phase cancels each other out. Does a panel do the same thing?

When i first got into car audio i played around with woofers in cabnets and i found 2 woofers in the same box sounded better out of phase. I didnt know why thery sounded so much better at the time it was an accedent i wired one of them wrong and the bass to me sounded way better.

Ide have to try them and see what it sounds like in and out of phase on the same panel.

[sedge]

Zygadr
Oh no you had to ask .I was hoping to get the other panel with all the drivers set up so I could say whether they were any good or not .
The one panel sounds good,  but I had to use blue-tak strips to  dampen what I call self- noise - this is probably all the frequencies  bouncing around the panel ,just like a paper cone .also  the 4x2 ft size [max ] is obviously a problem ?.
I?m running short of time so will have to get back to you.

[usp1]

The number of exciters seems to make a difference in the HF response. With one exciter my 2'x4' gatorfoam panel goes up to 15Khz with 2 exciters the HF rolls off at 12Khz and with 3 or more it is lower still around 11 Khz. I presume the multiple exciters must be canceling out the high frequencies. I wonder what role spacing between exciters plays.

(I tried different spacing and it did not seem to make any difference)

After reading some of the earlier discussion about dipole vs. bipole, I thought I'd try something very different - exciters on both faces of the panel. Complete Fail! The sound was just awful. The exciters must be canceling out.

[BowerR64]

I think the dayton exciters sound better

[sedge]

zygadr
the only quick thought I have on this is that the centre of the exciter is a very efficient 1inch flat tweater,by cutting it out this could reduce the hf  beaming and give a more even midrange and hf responce.
this is a very small panel and would probably tend to be over bright sounding I would have thought ?,any thoughts on this anyone?.

[BowerR64]

What about the panel thickenss? Does it have any change in bass or fullness?

I gave a couple to my friend but he didnt have any of the gator board, he used a section of 1-1/2" thick foam and he said it sounded good but i dont have any to try.

I want to build a panel the size of a bookshelf with about the same fullness but lower profile. For rear surrounds, or even a center. I built a center but its a tad to thin sounding for what i like.

[sedge]

Yesterday I went on ziggys diy audio site ,it seems my panel is no good ,it is too rigid and light and under damped .the podiums[normex] got a bit of a bashing too ,for the same reason.we are all doooomed captain dooooomed!
If we could find a panel that did everything technically perfect it would be a miracle ,but a very welcome one ;but the thought of actually  trying to design the all singing and all dancing panel, that does every thing perfectly,this could be a miracle too far.
How many years have they been trying to find the perfect cone material ,oh yes this is the best because of this and that,but at the end of the day they all have there faults, that?s why paper cones are still out there,because a lot of people like the sound .
Im not saying paper is best ,all Im saying is that  if after a 100 years searching and testing you still cant find the perfect material, it probably aint there.
Could you imagine  in another 100 years, we have now got the so called perfect panel,then someone pulls an old lump of gatorfoam from a skip bin ,sticks an exciter on it and says ooooo I like the sound of this.
I think I will get that second panel and see how it sounds, you never know do you?. aa

[BowerR64]

I thought i had gator board but i guess its not, i guess i just have black foam core poster board. The black stuff i have is different then the white but its not near as rigid as what i read the gator board is.

I like the foamcore stuff it just needs to be bigger.

[bytheway]

I might be willing to remove the exciters off my panels to drill holes if it means possibly better high freq response.

Not really being a woodworker, or foam worker, would a hand drill be the right tool to make the holes? 

[captainjack115]

What about the panel thickenss? Does it have any change in bass or fullness?

I gave a couple to my friend but he didnt have any of the gator board, he used a section of 1-1/2" thick foam and he said it sounded good but i dont have any to try.

I want to build a panel the size of a bookshelf with about the same fullness but lower profile. For rear surrounds, or even a center. I built a center but its a tad to thin sounding for what i like.

[/b]

I stacked up several sheets of foam core and the output was reduced considerably.

Jack

[captainjack115]

I thought i had gator board but i guess its not, i guess i just have black foam core poster board. The black stuff i have is different then the white but its not near as rigid as what i read the gator board is.

I like the foamcore stuff it just needs to be bigger.

[/b]

I'm thinking of getting a 48X96 inch piece of foam core and having it cut in half  lengthwise then cut to 72 inches for both pieces.
I'll put 8 exciters on each panel, but before any I make big panels I'm trying the aluminum on the front.

This will require that the hole for the exciter is slightly larger than the diameter of the exciter. The next problem is having the end of the exciter be exactly at the proper distance to touch the aluminum sheet.

The sheet of the aluminum would need to be just thick enough not to bend or sag, then well glued to the panel as to allow a low loss acoustical coupling.
Joining two different materials in this manner, may just give us us the best of both worlds. Decent bass and just a slight boost to the high end, would be a good step towards a panel with acceptable characteristics.

Jack

[BowerR64]

I tried stacking the walmart type foam core also using elmers glue to stack them and it made the section i made more dense like a chunk of MDF or somthing wich sounds like dump.

So far the foam core is the best thing ive tried so far.

My next idea is to use a thicker type foam core i seen at this craft place here in KC called "joans" it looks 2X the thickness as the foamcore from walmart. Im going to cut out around the transducer then cut out the foam till i reach the front paper backing. Im then going to mount the transducer to the paper backing on the front but from the inside. I want the panel flush so i can hang it like a picture and it will lay flat against the wall without the transducer hitting the wall.

I think ill use small trim nails or toothpicks and dental floss or fishing string and attach the string to hang the panel on the edges of the foam core. I want to hang it fairly high up but have it point at a slight angle downward.

I have some craft foam with a sticky backing i could use as a wedge to push the top out so it gives a slight angle. Then the bottom edge of the panel will touch the wall and the sticky back foam on each side.

I figure if i mount the transducer in the center, then mount the dental floss or fishing string at the center it will pivot and very little of the panel will touch the wall. Or maybe i do want it to touch a little? i just dont want the panel to vibrate and create unwanted chatter.

I thought i had gator board but i guess its not, i guess i just have black foam core poster board. The black stuff i have is different then the white but its not near as rigid as what i read the gator board is.

I like the foamcore stuff it just needs to be bigger.

[/b]

I'm thinking of getting a 48X96 inch piece of foam core and having it cut in half  lengthwise then cut to 72 inches for both pieces.
I'll put 8 exciters on each panel, but before any I make big panels I'm trying the aluminum on the front.

This will require that the hole for the exciter is slightly larger than the diameter of the exciter. The next problem is having the end of the exciter be exactly at the proper distance to touch the aluminum sheet.

The sheet of the aluminum would need to be just thick enough not to bend or sag, then well glued to the panel as to allow a low loss acoustical coupling.
Joining two different materials in this manner, may just give us us the best of both worlds. Decent bass and just a slight boost to the high end, would be a good step towards a panel with acceptable characteristics.

Jack

I tried the aluminum and it didnt sound good for me either. I dont know how smokinjoe got it to sound good other then his amp might have a nice sound anyway. I need to play with mine more i havnt really messed with them enough to really say much. His didnt sound that bad though, it was threw youtube but it had a nice full sound. Mybe the sound was actualy comming from those other speakers?

His panels were only 12"X12" too i dont get it. Mine sound better the larger the panel is.

[BowerR64]

What do you think it would sound like if i cut out a section and suspend it with rubber bands?

I bought some of those 55 cent onkyo tweeters and they dont sound that bad.



Wich do you think would sound the best?