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

OB_Newbie · « **Reply #2320 on:** 22 Apr 2015, 12:53 am »

Quote from: caretaker on 21 Apr 2015, 04:27 am

Thanks OB.

Material is CC and not CG as I've written in previous post...sorry.
The sound?...
Oh my,....vocals are to die for, acoustic instruments amazing !!!
Only one condition; it has to be good recording.
Heights; can tell, doesn't go up to 20.000kHz, but it's not really noticeable in listening.
Bass: goes deep enough to give good foundation for overall listening experience.

Even if it sounds much better allready now than most conventional speakers, there is gonna be a lot of elaborating when I'll be back home.

Man, I have to try the CC. For a while here it looked like CC was the material of choice if it wasn't for the drop in HF at 10K. But a little EQ on the panels and I ought to be able to overcome this minor shortcoming... not all that much content... mainly harmonics in the last octave. "Natural" and "Mother of Tone" were the terms that many posters were saying about the CC treated with shellac. Hmmm... might have to see what CC I have around.

Thanks for the post and impressions!

OB_Newbie · « **Reply #2321 on:** 22 Apr 2015, 01:08 am »

Quote from: Odal3 on 21 Apr 2015, 05:51 am

Welcome aboard! Great to see more people from Indianapolis posting here.

Dang, my oldest son and I were in northern Indy (Westfield) Friday-Sunday for soccer... should have meet up you fellas for an adult beverage and some good food or something.

Saw that the Ultra's are out of stock. If anyone wants to try a pair I would be happy to ship a pair out for the sale price and actual shipping (bought a load of them while on sale). Should be able to ship in a padded envelop pretty cheaply I would guess.

caretaker · « **Reply #2322 on:** 22 Apr 2015, 01:15 pm »

Quote from: OB_Newbie on 22 Apr 2015, 01:08 am

Dang, my oldest son and I were in northern Indy (Westfield) Friday-Sunday for soccer... should have meet up you fellas for an adult beverage and some good food or something.

Saw that the Ultra's are out of stock. If anyone wants to try a pair I would be happy to ship a pair out for the sale price and actual shipping (bought a load of them while on sale). Should be able to ship in a padded envelop pretty cheaply I would guess.

Yes, too bad we've missed that opportunity.

Today I'm flying back home to Slovenia where I'll be able to get in to dml little more seriously.

My plan is experimenting with different tonewood using an idea from "goebel speakers" for eliminating reflections on the edges, and an idea from "JMC lutherie" for bendind wood. Also "Brigham Larson Piano" uses bending soundboard technique in their pianos.
Those are the things we haven't try already.

Odal3 · « **Reply #2323 on:** 22 Apr 2015, 04:02 pm »

Quote from: OB_Newbie on 22 Apr 2015, 01:08 am

Dang, my oldest son and I were in northern Indy (Westfield) Friday-Sunday for soccer... should have meet up you fellas for an adult beverage and some good food or something.

Hope there will be more opportunities

TXATC · « **Reply #2324 on:** 30 Apr 2015, 02:34 pm »

Update: Finished the front 3. 22x35.5 in. Painted up and sounds b-e-a-utiful! The suspension still needs a bit of work as they are hanging crooked. Have an idea to fix that, I'll let yall know how it goes.

Panels are 1 in thick. I used an orbital sander with 150-220 to sand the faces down nice and smooth. Velvety texture and looks amazing. I then painted using titebond3 and water with some printer ink off of Amazon that was cheap. Took 2 coats to get this black. I tried just with water and ink to color but the ink never dried and kept rubbing off anytime you handled it.

After sufficient drying time, I took the painted panels to the router table and used a 1/2 in roundover bit on the edges. The result was a nice clean line of what's painted and what's not. Then took 800 grit and polished up the routed edges for a more finished look.

In short I very happy and the process was not taxing at all. Thanks for the input and I'll let you know how it sounds when it's all finished.

Frank40 · « **Reply #2325 on:** 1 May 2015, 11:39 am »

Hello....

I am new to this forum but I have been reading this thread from post one now, and find it very interesting. I am not new to building speakers or speaker units, but I have never tried this type of speakers. And I thought it was a good way to learn something new.

I have been looking to find the perfect exciter but couldn't find one that I liked, so I designed my own based on a 100 mm magnetic structure.... here is how looks now, just a quick prototype.

Now for some questions......

I am looking for the best material for the membrane and suspension type for a full-range unit, and was hoping some of you would care to share your experiences with me.

Odal3 · « **Reply #2326 on:** 1 May 2015, 09:17 pm »

Interesting. Unfortunately don't have any design solutions for you. Have you looked at the solutions used by commercially available exciters? I have a cut up exciter i can take a pic and post. Curious to hear more about your design goals and what in the currently offered exciters that you didn't like.

Odal3 · « **Reply #2327 on:** 1 May 2015, 09:19 pm »

Quote from: TXATC on 30 Apr 2015, 02:34 pm

Update: Finished the front 3. 22x35.5 in. Painted up and sounds b-e-a-utiful!

WOW! Super nice. Please post a closeup picture in good light

TXATC · « **Reply #2328 on:** 2 May 2015, 03:56 am »

Thanks Odal! Unfortunately that's as bright as it gets in there. I will be making the surrounds this weekend. I will document the steps if you would like me to. If you want to let me know what you want to look at I will post just those pics after they're all said and done. Just let me know.

Semper Fi

Odal3 · « **Reply #2329 on:** 2 May 2015, 04:12 am »

I'm mainly curious to see a closeup of the edges.

Needed new exciters and the thrusters are in backorder for a few months so I took a chance on the DAEX30HESF-4 HIGH EFFICIENCY STEERED FLUX exciters. Quick listening test holding it up to the panel was very promising. Most interesting thing was that they sound much louder unmounted than any other exciters I have tried. So I'm "excited" to put them up properly tomorrow

Frank40 · « **Reply #2330 on:** 2 May 2015, 11:44 am »

Hi to all,

First let my say.... after reading my fist post again I realised what I was saying, it was not my intention to say what you guys is doing is not good. Actually I was very inspired by this thread.

Second I must say that I have a bad habit of taking things to the extremes......

But the exciters that I have experiment with was not to my taste. The magnetic structure was not optimised for maximal linear flux in the gab, Xmax is to low for my taste, low power consumption, also I don't like when they use alum. for voice coil former due the the Edison current effect. And high induction due the the lack of copper cap.

Odal3 · « **Reply #2331 on:** 2 May 2015, 12:33 pm »

Frank - not at all. I'm really curious to learn more and if your experimenting works out, if be the first in line to try to do something similar

I just don't have the skills and knowledge to do it myself so I'm very curious in a positive way to follow your work. I have one cut up from before that I wanted to do some experimenting with.

The pics you posted, are those your own design? It looks somewhat similar to the Dayton 30hesf exciter I just got (smaller Dia on magnet than the thruster and ultra exciters)

What I have found is that to some degree the panels themselves have a big impact on the sound - perhaps more than the exciters.But I agree with you that some improvement on the exciters would be good and perhaps exciters that are optimized for bass and some that are for mid range and up.

TXATC · « **Reply #2332 on:** 2 May 2015, 05:45 pm »

Gotcha. I just ordered a new bullnose router bit that should be here Monday I think. I'll give that a whirl and post up close pics of the edges for you.

sedge · « **Reply #2333 on:** 2 May 2015, 09:44 pm »

frank40
that looks like a powerful motor which could drive heavy wood type panels. but I would still use a very light panel material and mount the coil directly to the panel,
the amount of power in reserve could be used to EQ the response of the panel below 300HZ or so, room cancellations willing.
should be interesting on a large panel.
what size panel are you thinking of?
sedge

Frank40 · « **Reply #2334 on:** 3 May 2015, 07:50 am »

I am glad that that my first post was not taken the wrong way.....

It is my own design it is the first prototype, Now I am working with a new one with two spiders to reduce the amount of rocking motion. See pic.

I have some 140mm 3.8Kg magnet structures in order, also me design. I ordered 25pcs. So I want to try them for exciters as well.

I think first try will be 2 X 400 X 1000 mm Depron, and take it from there... if you have other suggestions please let me know.

Take care

soldermizer · « **Reply #2335 on:** 4 May 2015, 03:45 am »

I am very new to DML and just a tinkerer so be gentle with me

Has anyone used dual exciters in push pull on opposite sides of a panel? Usually done with sub's isobaric, done here you get twice the force into a panel.

Odal3 · « **Reply #2336 on:** 4 May 2015, 04:24 am »

Welcome on-board!

Haven't tried it myself, but according to the plots on page 29 in this study it looks like it reduces the output (unless there were measurement/amplication errors).
http://www.diva-portal.org/smash/get/diva2:567037/FULLTEXT01.pdf

But, the panels described in this thread are a bit different than those, so who knows. I think a common theme on this thread is that many ideas that have been tried have shown both better and worse result than theorized. There is only one way to find out - to try it!

Odal3 · « **Reply #2337 on:** 4 May 2015, 04:37 am »

Quote from: Frank40 on 3 May 2015, 07:50 am

It is my own design it is the first prototype, Now I am working with a new one with two spiders to reduce the amount of rocking motion. See pic.

Nice! Curious to see how you like them once completed. Do you have a panel in mind for the exciters? With a lot of force you need either large or rigid panels with high dampening. When I put two of the 40W Dayton exciters on a 1/4 thick birch panel I got too much vibration which messed up the sound.

Are you using the 6 tabs to mount it?

soldermizer · « **Reply #2338 on:** 4 May 2015, 01:39 pm »

Odal3: thanks for the welcome. I am mostly active on DIYaudio and my latest obsession is working on DML. I have been browsing this archaeic thread here too. I didn't even recall I had an account from years ago

Your comment bolsters my feeling that DML is very much an art form. Surely it is one of the cheapest DIY projects available for the stereo nut

And believe me, I know cheap!

I've only been doing DML for about a month; I have yet to even try a off the shelf exciter. I probably should since they are reasonably priced. You can get ok results using "normal" drivers (I have used some autosound speakers I had on hand) but of course there is more hassle mounting them to the panel.

I think one of the big challenges will be how to "disguise" the panel(s) once the tinkering is done and I am satisfied with my (currently) irregular trapezoid with two ugly drivers, wires dangling, hanging from ceiling hook by two strings

Of course, retail or quality DIY versions will have a frame or some kind of covering. I am assuming these panels are so (pardon the pun) flexible that they could be anything from a room divider to something framed on the wall (yes, you lose the rear output...) For DIY horrors like mine, and this should be easy, why not just cover with dark fabric of your choice?

I am zeroing in on what seems easiest for a single (big?) panel: 100 Hz to perhaps 10K, arguably full range but needs help on the bottom certainly. Amazing what you can do with a pair of $15 Wal*Mart auto drivers and a 4x8' sheet of foam from the home improvement store plus (in my case my favorite adhesive) Gorilla Glue.

Frank40 · « **Reply #2339 on:** 4 May 2015, 02:00 pm »

Dose any of you know of this material it is called XPS 300., it is very stiff and has a weight of 32Kg/M3. I used to make models RC controlled jet planes with this stuff. It can be cut to any thickness with a hot wire...... very easy to work with.