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

Bendingwave · « **Reply #3140 on:** 3 Nov 2018, 11:38 am »

I never said the basics is not important....other then helping one choose the ideal panel (which is a given) to start off with, it does nothing to help one increase the sound quality of ones panels.

Sure the formulas can help one save some time when choosing the right panel material but its no different then someone explaining what is the right panels to choose and why. It seems like we are arguing semantics so I am just going to move on.

embty2002 · « **Reply #3141 on:** 17 Nov 2018, 02:07 pm »

hi to all, public 2 measures made with REW.
the green one is about a polystyrene panel size cm 45X50, while the blue one is cm 50X90. as you can see on the smallest panel there is an annoying peak on the 12K hz, which is totally absent on the largest panel. I think to use the largest panel for my three way system. Do you have any suggestions about using a tweeter? the measurement is not bad up to 20K
Thanks

embty2002 · « **Reply #3142 on:** 17 Nov 2018, 02:12 pm »

i used a EPS 30kg/MC , 1 cm panel painted with vinyl glue 50% water, 2 rear, 1 front. tectonic teax25c10-8/sp

embty2002 · « **Reply #3143 on:** 17 Nov 2018, 05:39 pm »

i hope to be clear, red is the 45X50x1 cm EPS panel, in violet the 90X50X1 cm EPS panel.
the violet is my favourite

Kame2 · « **Reply #3144 on:** 18 Nov 2018, 08:28 am »

Hey Embty,

you panels seems like a good starting point. The peak at ~11 kHz on your smaller panel seems a bit strange. Have you tried other positions of your panel and measurement mic? Maybe it was just a special configuration of these? You could also test other positions of the exciter. But that should have much more influence on the lower frequency parts.
Did you have a frame or are your panels free floating? Do you use a spline to support your exciter?

(We are moving tomorrow. So I am currently not very active here. This situation may hold for some time as it seems the ISP will still need some weeks to install the needed hardware at the newly constructed building)

embty2002 · « **Reply #3145 on:** 19 Nov 2018, 07:09 am »

Yes, the red has the spline

nicw1 · « **Reply #3146 on:** 21 Nov 2018, 01:37 pm »

First post here !

After dusting down my 15 year old Mission X-Space NXT panels and making these useable by wiring the 4 ohm exciters in series rather than parallel , I have decided to take the plunge and build some panels .

I have decided on the following design using a Dayton DAEX25FHE-4 and 20mm pink 'prowarm' XPS board . These will be used from a few hundred hz upwards . The exciter will be mounted to an edgeless 'T' frame , the top being suspended by elastic bands , the bottom edge sitting on a pair of triangular makeup sponges (marshmallow type consistency no idea what these are made from) . The XPS board will be cut into 600x500 pieces (approx 4:5 ratio) and will be sanded / treated with 50/50 water/PVA mix . The corners will be rounded using a CD as a suitable template and the edges will be radiused with a roundover router bit

I would like others to comment on the viability of this design . I have trawled through a considerable amount of this thread and it's been a real learning curve , I still have a few questions (providing the design is sound in the first place !):

Should the panel edges be treated and what is the recommended mounting position ? (Dayton/Monacor or ?)

cheers

Nic

Bendingwave · « **Reply #3147 on:** 25 Nov 2018, 02:56 am »

What made you choose to use elastic bands to suspend your panels while the bottom edges are sitting on cosmetic triangle sponges???

If you liked the sound of your Mission X-space nxt panels why not try to mimic the designs of those panels first?

nicw1 · « **Reply #3148 on:** 26 Nov 2018, 09:26 am »

Quote from: Bendingwave on 25 Nov 2018, 02:56 am

What made you choose to use elastic bands to suspend your panels while the bottom edges are sitting on cosmetic triangle sponges???

If you liked the sound of your Mission X-space nxt panels why not try to mimic the designs of those panels first?

The old x-Space panels are too small , it's just an A4 sized panel of two rear-supported coin-type exciters , not particularly impressive extension but quite sensitive . New panels are built and working , the only mishap was that the VHB adhesive pads had issues sticking so have removed and stuck the exciters to the panels using PVA . After running for a day unsupported , have built some stands . For the time being I'm going to leave the top edges unsupported . I can't get any double sided tape to stick to the sponges so for the time being , I'm resting the bottom of the panels on two dots of neoprene

Overall the sound is promising . Current setup has the panels with a passive 1st order filter set to 120Hz at the input of the amp .

cheers

Nic

embty2002 · « **Reply #3149 on:** 27 Nov 2018, 04:06 pm »

Quote from: embty2002 on 17 Nov 2018, 05:39 pm

i hope to be clear, red is the 45X50x1 cm EPS panel, in violet the 90X50X1 cm EPS panel.
the violet is my favourite

I would like to cross my DML panel with a tweeter. I have monacor rbt 95 sr and fostex ft17h, possibly. considering that remarkable peak on 12k hertz, who helps me to build a passive crossover? thank you

nicw1 · « **Reply #3150 on:** 29 Nov 2018, 07:03 pm »

I'm a few days in with my 50x60cm 20mm XPS panels . I sanded then treated the XPS with a few coats of PVA/water/ink . Exciter used the Dayton Audio DAEX25FHE-4 with classic 3/5 spacing . I pulled off the VHB gunk and stuck the drivers using PVA .I am finding some annoying qualities such as the sound appearing from the rear of the panels , panels also still sound very tinny run full range . The sound is clear but little focus and an apparent lack of air . I am wondering how long typical panel/exciter break in lasts for such a panel

cheers

Nic

Bendingwave · « **Reply #3151 on:** 3 Dec 2018, 09:23 am »

I would of used 2 part (5min.) epoxy adhesive instead of PVA glue....Even the type of adhesive can affect the sound.

Annoying sound from the rear of the panels is due to the vents in that particular type of exciter...I prefer the exciters without vents.

Tinny is mostly due to the type of material in your case XPS, which is the reason I prefer EPS for its warmer less tinny sound.

One way to provide more focus is to use a frame for a more foward directional sound.

When using a frame you must use some type of weather strip foam or rubber to attach the panel to the frame so that there wont be any distortion from two solid objects touching each other....I use frost king brand available at Home Depot.

Not sure about how long for a exciter to break in but a brand new exciter is stiffer then one that has been used a while.

alvipet · « **Reply #3152 on:** 6 Dec 2018, 04:15 pm »

Quote from: koko007 on 18 Sep 2018, 09:19 am

And this is measurement of Russian speaker:

Impressive!

Here you can hear how it sounds in the recording
https://youtu.be/j5ww2Fgd9D8
https://youtu.be/2aXVxbXcS3w

nicw1 · « **Reply #3153 on:** 7 Dec 2018, 09:29 pm »

Quote from: Bendingwave on 3 Dec 2018, 09:23 am

I would of used 2 part (5min.) epoxy adhesive instead of PVA glue....Even the type of adhesive can affect the sound.

Annoying sound from the rear of the panels is due to the vents in that particular type of exciter...I prefer the exciters without vents.

Tinny is mostly due to the type of material in your case XPS, which is the reason I prefer EPS for its warmer less tinny sound.

One way to provide more focus is to use a frame for a more foward directional sound.

When using a frame you must use some type of weather strip foam or rubber to attach the panel to the frame so that there wont be any distortion from two solid objects touching each other....I use frost king brand available at Home Depot.

Not sure about how long for a exciter to break in but a brand new exciter is stiffer then one that has been used a while.

Thanks for your input , much appreciated . I suspect that tinniness can be tamed , it's definitely the rear side combining with the front . I don't have many options for placement such as pulling the panels out from the walls so I've placed some open cell foam on the frame behind the driver , then draped some long haired wool over that which was better . I have a few sheets of Rockwool RWA45 , I'll cut out a piece , wrap it around (then clamp to the frame) and give that a try

In terms of closed back exciters , what would you recommend ? Are the smaller sub 20w Tectonic Elements drivers worth looking into ? Much easier for me to obtain in the UK...

cheers

Nic

Bendingwave · « **Reply #3154 on:** 8 Dec 2018, 03:32 am »

Quote from: alvipet on 6 Dec 2018, 04:15 pm

Here you can hear how it sounds in the recording
https://youtu.be/j5ww2Fgd9D8
https://youtu.be/2aXVxbXcS3w

It sounds good....What is the panel material they are using, Antinox?

Bendingwave · « **Reply #3155 on:** 8 Dec 2018, 03:38 am »

Quote from: nicw1 on 7 Dec 2018, 09:29 pm

Thanks for your input , much appreciated . I suspect that tinniness can be tamed , it's definitely the rear side combining with the front . I don't have many options for placement such as pulling the panels out from the walls so I've placed some open cell foam on the frame behind the driver , then draped some long haired wool over that which was better . I have a few sheets of Rockwool RWA45 , I'll cut out a piece , wrap it around (then clamp to the frame) and give that a try

In terms of closed back exciters , what would you recommend ? Are the smaller sub 20w Tectonic Elements drivers worth looking into ? Much easier for me to obtain in the UK...

cheers

Nic

https://www.parts-express.com/tectonic-teax25c10-8-sp-25mm-high-power-8-ohm-frog-exciter--297-206

T.E. exciters IMO have a warmer sound then the Dayton exicters.

alvipet · « **Reply #3156 on:** 10 Dec 2018, 07:37 pm »

Quote from: Bendingwave on 8 Dec 2018, 03:32 am

It sounds good....What is the panel material they are using, Antinox?

honeycomb paper. There are some more records from Russia:
https://youtu.be/7gAYd6sdox0
https://youtu.be/VPew6zviYhY

Bendingwave · « **Reply #3157 on:** 14 Dec 2018, 11:17 pm »

Quote from: alvipet on 10 Dec 2018, 07:37 pm

honeycomb paper. There are some more records from Russia:
https://youtu.be/7gAYd6sdox0
https://youtu.be/VPew6zviYhY

Ah ok....What are they using for the skin? Mylar, carbon fiber?

alvipet · « **Reply #3158 on:** 21 Dec 2018, 03:39 pm »

American acrylic paint and lacquer.

Dicko101 · « **Reply #3159 on:** 6 Jan 2019, 02:18 am »

Hey everyone, been following this thread for a while, decided to have a go, I made some panels with 30mm XPS foam, 600mmX970mm, sanded, treated with 2 coats of 50/50 PVA/water, suspended by a small nail in each top corner from fishing line, using DAEX30HESF-4 at golden ratio. I was really looking forward to enjoying these panels but I'm finding them very bright, pitchy and thin to listen to, even with the support of a sub they don't seem to have enough body, is there anything I can do to improve them in the midrange without EQ? I don't have an EQ or RTA so I can't measure them, but I would really like a bit more depth from them.