[Liviu]

Hi guys!

I'm new to this type of drivers and I am not sure about the mounting holes fitting.
For example the
http://www.daytonaudio.com/index.php/daex30hesf-4-high-efficiency-steered-flux-exciter.html
DAEX30HESF-4
To my mind, the driver's mounting holes would be fitted to an independent fixing point, not to the board that is supposed to vibrate, so that the mass of the driver is fixed and immobile, and thus "resting" and be able to push more of the energy into the vibrating board.
But I can't find anything detailing how these holes are meant to be used.

Thanks!

[Bendingwave]

Those are mounting holes to be used the same way one would mount a speaker on to a open baffle or spline...You are correct as its used to hold the exciter in a fixed place so that all of the pushing energy is directed to the diaphram material used.

[Bendingwave]

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.

XPS material can sound a bit bright that is why I use High Density EPS for its warmer tones...30mm is a little too thick, try 10mm....Pitchy and thin is most likely due to your design of hanging them from a fishing line. (not sure where you got that idea from, Tech ingredients video?).


If you want more depth from them then you will need to change your design and make them "Floor Standers" which utilizes a frame to hold the diaphram material in place and a spline to hold the exciter in place.


It would look something similar like this> i88.servimg.com/u/f88/13/48/14/85/img_0337.jpg

[Dicko101]

XPS material can sound a bit bright that is why I use High Density EPS for its warmer tones...30mm is a little too thick, try 10mm....Pitchy and thin is most likely due to your design of hanging them from a fishing line. (not sure where you got that idea from, Tech ingredients video?).


If you want more depth from them then you will need to change your design and make them "Floor Standers" which utilizes a frame to hold the diaphram material in place and a spline to hold the exciter in place.


It would look something similar like this> i88.servimg.com/u/f88/13/48/14/85/img_0337.jpg

I've wanted to house them in a frame but I wasn't sure about suspension material, the reason for the fishing line was because I got the impression from the forum that the least interference with the edges of the panel the better. I will try to frame them if I can find something suitable to hold them.  I only had 30mm available to me but I thought it might be more efficient anyway, being more rigid I thought it might transfer the energy from the transducer more effectively.

[Bendingwave]

Suspending the panel material to the frame you will need to use some type of foam or rubber....I use the Frost King rubber foam weather strip tape.


This is how you mount the panel material to the frame > http://img.auctiva.com/imgdata/1/6/6/4/9/3/0/webimg/561777455_tp.jpg


Thinner panels are more effecient and produce better more accurate bass due to thinner panels being able to bend or flex more.....Thicker more rigid panels produce better highs BUT less bass because it does not bend as much as thinner panels.

[Bumpy]

What makes you say they are real NXT speakers? There have been many other drivers/speakers designed along similar lines over the last 35 years at least, to my knowledge.

I owned Podium 0.5's from new. Their patents put clear water between themselves and NXT.

They were well mannered speakers lacking in any real bass, but very listenable. I consider one of the unique features were the 'tuning' fingers put around the perimeter of the panels to tune and optimise them. These were tuned individually by Shelly Katz the inventor and professional concert pianist with a fine ear.

[dguillor]

Hi guys!

I'm new to this type of drivers and I am not sure about the mounting holes fitting.
For example the
http://www.daytonaudio.com/index.php/daex30hesf-4-high-efficiency-steered-flux-exciter.html
DAEX30HESF-4
To my mind, the driver's mounting holes would be fitted to an independent fixing point, not to the board that is supposed to vibrate, so that the mass of the driver is fixed and immobile, and thus "resting" and be able to push more of the energy into the vibrating board.
But I can't find anything detailing how these holes are meant to be used.

Thanks!

Yes, you need a brace to hold the exciter for that one. There are some that don’t need a brace because they have a very stiff suspension between the voice coil and the magnet. The Dayton Thruster is that way and has a nice sound.

[BOONTOK]

I did a quick prototype of a Dayton Audio DAEX30HESF-4 on a 3/4" XPS panel approximately 3'x2', built a 2x4 frame around it, and used construction adhesive to make it as rigid as possible.  The sound was incredible, with good lows and decent highs (and I didn't even sand/coat yet).  The excited was not suspended in any way.  My only concern is that the exciter will sag over time and the voicecoil will rub. Is there a method of suspension that would not change the acoustic properties too much, like maybe using monofilament to "pull up" on the back of the exciter just a bit?  Thoughts?

[mobilgin8330]

7. From what I hear in my listening room, the sound of a DML is so far superior to other...
Rob.

Fantastic reading,but what ia a DML ?

[DaveToa]

DML speaker

Distributed Mode Loudspeaker (DML) is a flat panel loudspeaker technology, developed by NXT, in which sound is produced by inducing uniformly distributed vibration modes in the panel through a special electro-acoustic exciter.

en.wikipedia.org/wiki/Distributed_mode_loudspeaker

[DaveToa]

After having read the 159 pages here and the article at Parts Express, I have embarked upon a DML speaker project. I purchased two pair of exciters from Parts Express.

As a proof of concept I purchased 4-poster board panels from the Dollar store. I painted a pair of the panels with the white glue and water  (2 coats to one side and 1 coat on the opposite side. The poster boards had the paper facings on both sides.

I first tried a 12"x12" 1/4-inch piece of red oak plywood. I was surprised at how rich was the sound. the Board was balanced horizontally upon the exciter and not permanently attached.

I then laid one of the poster boards upon the exciter (horizontal -- not glued). There was a lot more volume but the warmth that came from the Oak plywood was lacking. These 30"x24" poster boards with paper surface proved to me that the concept was worth pursuing. 

I have since purchased 1/2-inch XPS sheet and had it cut to 48"x30" (size based on golden ratio). I have sanded the panels with both 100 and 220 grit. I plan to ease the edges with a 1/4-inch router round over bit. I will coat the surfaces with the water and glue. I then intend to glue one exciter to each panel 2/5 away from the edges of one corner.

My musical preference is acoustic instruments (Jazz, classical), vocals, and some pop/rock. I am most concerned about the feeling of a live performance, i.e. bass. I recognize the current size definitely does  NOT meet the wife appreciation factor. I own a couple of sets of sub woofers which may be employed if I opt for smaller panels.

!. Does any one have a suggested size smaller than what I plan to test that will yield that live presentation without a subwoofer?

2. I would like to paint the panels with black epoxy paint. Should this be applied over the glue mixture; or should it be applied directly to the sanded panels?

3. Having four 4-ohm exciters I can use one pair for highs and the other 2 for bass. Any suggestions as to panel size and thickness.

TIA

Dave

[Miiksu]

Hi, I'm new also. I had to register because I have been watching vibration speakers a year now. I have now very first my own hybrid vibration flat speakers and they sound awesome. They seriously need a woofer or woofers. I have two cheap philips 5" woofers but I'm planning to upgrade them to something better. So on my flat speakers I have six dayton audio exciters and an orthodydamic tweeter. And yes a tweeter is needed also if you want the highest frequencies more prominent.

@DaveToa I used approx 115x61 cm, 3.3mm composite panel and covered the back with sound deadering material. Works very well. I say keep the panel very thin. I have not tried yet exciter bass shakers. It could work on own a big panel that resonates easily and should move a lot and hook it to sub output on the amplifier.

Keeping the exciters in the middle gives low frequencies, midrange. Going to up and top of the corners gives the highest frequencies.

My guide. Its bad but hopeful you get the idea.

[FullRangeMan]

Nice panel congratulations, maybe you can pass pro-audio bass shakers they was not good in tone definition when I had listened a few years ago (1990s).

[Miiksu]

Nice panel congratulations, maybe you can pass pro-audio bass shakers they was not good in tone definition when I had listened a few years ago (1990s).

Thank you. I bought Dayton Audio mini puck bass shakers. I want to test those potential.

My parts for each speaker:
Akai 4IT-SM3G
DAEX25X4-4
DAEX25W-8
DAEX25CT-4
And old Philips 5" 30W 6 ohm woofers.

Full costs for a pair speakers only, no woofers or an amp included was 240€. Woofers and aluminium coated composite panel was free I had to buy somehow decent amplifier so I can adjust treble and bass levels. TPA3116D2 2.1 amp with power supply was 59€. Plus extra opamps for your liking.

AKAI tweeter


Avarage measurement with pink noise. This is not final.


How I put everything together. No crossover. I just wired everything together and reinforced exciters so they don't blow away. 




 

[AJC Acoustics]

Not sure if my last message posted here!

Hello to all you DML enthusiasts!

In the iterative quest for the perfect DML design, I've become familiar with composite design and manufacture and have created a sandwich composite using Nomex aerospace grade honeycomb and carbon fibre combined with bio-fibre twill

The result is cheaper and lighter than using carbon fibre alone. As we know performance can be subjective in home made speakers, so I'd really like to get these panels into the hands of people who can give an objective perspective and hopefully measurements.

Currently 3 panels is est £160 in materials, not including the cost of labour, also not including the tooling set up cost of Vacuum pump, disposables and PPE. If you plan to follow in my footsteps it gets expensive quickly, and you need adequate ventilated space and proper protection equipment when cutting carbon fibre. The process can take up to three days to make one sheet dependant on the method of fabrication. It's an expensive, dangerous and time consuming process be warned.

I'd really like to do a small batch, if I were how much people would be willing to pay for a composite panel of around 500mm x 400mm? (I'm able to do iterations on size and ratio per request, this round aiming for 500mm x 395mm)

[Miiksu]

@AJC Acoustics Sounds interesting. Hope you get people to help with that project.  Someone could do some measuring solid panel vs honeycomb panel.

My hybrid speaker is not perfect but it has something magical to it. I'm listening radio and when hearing a good song I just can't help myself to go closer to listen. It just fulling the room with music. I need to do more measurements when I have time. I got fixed the impedance of the speakers and made some tuning adjustments. Re-wired the exciters to get both speakers 4.1-4.2 ohm. Before it was way too low for the amplifier. If I build more of these kind speakers I'll do it with the 20w exciters.

Also making my own subwoofer to get bass response better. Now Its kind meh with the philips woofers but its still a lot better than without. Also I can do some recording. But I don't have proper microphone for that. Audio quality sucks but you can hear the frequency levels. I publish more measuring and recordings when I get the subwoofer done.

[AJC Acoustics]

@Miiksu Nice work on your panel, and especially for getting it for no money ! Filling the room with music is a good way to put it, I love that it's a completely different listening experience to normal speakers! Have you built a frame for you panel of interest? From posts I've read here Bendingwave swears by them! 

[Miiksu]

@Miiksu Nice work on your panel, and especially for getting it for no money ! Filling the room with music is a good way to put it, I love that it's a completely different listening experience to normal speakers! Have you built a frame for you panel of interest? From posts I've read here Bendingwave swears by them!

No frame. Bare panel with dampering material clued to the back. Not sure about that bendingwaves. I think its because its bare sandwitched aluminium panel and soundwaves coming every direction but only the backside is dampered. On my measuring 5 kHz is slightly recressed and upper treble has some unevenness too. It was measured on listening spot, approx 2 meters of the speakers. Composite panel is cheap stuff but u have to buy it large quantities.

Also I tried some different subwoofer configurations and best was keep the woofer facing away from the listener and port hole to the listener. It's not smoothest on bass side but sounds alot airier and better impact. 

[SteveTH]

Hi everybody,  I just thought I'd share my limited experience playing about with audio exciters.

I first found out about Exciters from Tech Ingredients' YouTube channel and just had to try them, I ordered 4 x Dayton DAEX32QMB 32mm 40W 4 Ohm exciters from Amazon, these are the 'MaxBass' variant.  I tested various materials and the best choice seemed to be attached to the soundboard of my ancient Yamaha acoustic guitar but that was not what I wanted so I settled on a composite of 2cm thick polystyrene with a backing of corrugate plastic artboard bonded together with wood glue and attached a single exciter.



The sound was very different from 'normal speakers' a strange effect of feeling the performer was in the room but the range levels (frequencies?) were all over the place and bass was there but just not really resonating even with a little tweaking from the graphic equalizer (yes, I know but I like late 1980's kit).  Still speakers made up of scraps from an art project are pretty cool.

Today I went to get more art supplies and glue intent on improving on the design however fate stepped in and a flat battery scuppered that plan, so I rooted around to see what else I might have and I found a 10 year old Lian Li PC case, this particular case was quite unique and made of aluminium, anyway I thought I'd try out the side panels.  Wow!  The sound range really opened up with punchy bass and bright high tones.  I added a second exciter in series to the panel which contrary to what I was expecting improved everything, then a little tuning with the EQ boosting the 1KHz and 15KHz range and I am absolutely loving these speakers. Oh I almost forgot they can get very loud without any discernible distortion to my old, untrained ears.

Front View


Rear View





Now one thing I think was very lucky is that the panels had rounded edges, another feature to note is that the outside edge has very small serrations around it's perimeter but heavens knows what difference it might make if any.  The panels are roughly 44cm on each side, 1.8mm-2mm thick made of black anodized aluminium and would look stylish in almost any setting.

[SteveTH]

A little bit more info on the aluminium exciter speakers:

I uploaded and Android app that measures the frequency amplitude, defeated the graphic equalizer and then ran a sweep between 50Hz and 20KHz.  The results are shown below on the red line (ignore green line).





If I am reading this correctly it appears my ears are not as bad as I thought, there is a noticeable drop at around 650Hz-1KHz and a wider trough spanning 8.5KHz to about 14KHz which corresponds to my original 1K and 15K boost adjustments when using the EQ.  I read a lot of people saying not to use an EQ but for me bringing up those quieter frequencies makes a big difference and is worth it.


I have not mounted the speakers yet and they are currently resting on small polystyrene blocks on the floor and against the wall.  I don't think a frame would serve any acoustical purpose plus due to the rigidity of the material they transmit a lot of energy into whatever they come into contact with however suspended within a good looking free standing frame might work (thinking dinner gong).