I use a tap on those holes on the 25FHE's and mount from the rear through the spine. I have many photos in prior posts.
Let us know how they sound, compared to others if possible. I hope they sound great.
PS.
Some readers may wonder why no 'progress report' on my project ...
Because I don't have a sheltered workshop and I need to cut timber outside,
I am now waiting for this crazy S/E Australian weather to pass.
It's been one delay after another and I'm quite frustrated to get on with it 😕
Some readers may wonder why no 'progress report' on my project ...
Because I don't have a sheltered workshop and I need to cut timber outside,
I am now waiting for this crazy S/E Australian weather to pass.
It's been one delay after another and I'm quite frustrated to get on with it 😕
veleric said:
In that case, 14" it is. I got my second panel. Not as nice as the other one, but will probably do. I assume you haven't tried it with a coat of polyurethane. (would be nice to have a finished look eventually).
veleric said:
Interesting. I think I'll clamp the edge of one to see the difference.
veleric said:
I have a few bases for the removable thrusters still so will likely share those with my other panels to start with. I'd like to try the FHE-4 though; I'm getting together a PE shopping list for January, but still deciding on what I want. at 13$ a pop, I'll get at least 4 of the FHE-4s on that order. Do you have any recommendations on where to place 2 exciters on one of these panels? what about 4? (just in case i get greedy!!)
I would be very interested to know what the effect of a very thin coating of hard epoxy would be on a plywood panel. Rust-Oleum has an appliance epoxy spray paint that one could try. No doubt it would add more weight to the panel but appart from the finishing effect (say matt black), it could also add stiffness to the panel or even increase the HF possibly. Pure speculation now. One would have to measure the effects of spray painting the panel on one or both sides.
"Rust-Oleum® Specialty Appliance Epoxy is an ultra-hard, moisture resistant enamel"
Again, using support is not mentioned in any instructions from manufacturer or distributors, in fact they recommend against it, and they get damaged with time even if they are supported it seems.
Xcite exciters even lacks a way to support them.
Perhaps you should contact Dayton and Soundimports and explain to them how they do not understand their own product, and inform Xcite that their design defies your "common sense"?
Yes, very odd indeed.
It seems that the technical writer of the (Dayton? PE?) articles has never even held one of these drivers in their hands, much less worked with them for an extended period.
The high-lighted extract above implies that the screw-down mounting tabs must be fastened to the panel, and not to a rear support. Silly.
But there are other issues at play. The drivers are not designed by Dayton Audio. The OEM is BillionSound in China. So either the article is written in Chinglish, or the (American?) writer translated from the OEM's descriptions and got it wrong.
This leads to further questions regarding the depth of experience of both Dayton and Parts Express with these devices. From what I have seen, there are many on this thread who are far more knowledgeable and experienced than the technical "advisors" on those fora.
So, given all of the above in this current discussion, there are two possible issues at play regarding long-term usage of these drivers. One is the magnet mass which will inevitably modify the voice-coil/spider/suspension that supports that magnet. There's no getting away from that problem; The second is that the voice-coil/panel interface is a fragile one, and needs to be reinforced.
And both of these issues will lead to rubbing or distortion or crackling at high SPLs. So I will nevertheless brace the magnets of the larger drivers that I use. When I get the XT32-4 Xciters I will mount them with silicon into a cavity on a rear brace even just to ameliorate the sagging issue. Smaller drivers with adhesive legs will operate just fine without being otherwise supported.
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Are you sure about that? Retaining design and making elsewhere is pretty common practice these days. Part of the reason for that is supply chains. Skills too but no doubt China will catch up in that area eventually if they want to,
A while ago I spent some time web crawling for examples. Rather thin on the ground but saw no examples that supported the exciter. The idea doesn't seem to have been used by NXT even with DERA backing. Say some one goes down the oblong sheet of XPS with offset exciter(s) rabbit hole and supports it. The exciter will be subject to an unequal directional side loads. Other situations. Just what is the stroke length of an exciter when it's in use? It's complex and intended to create vibrations in a panel. Totally different to the pistonic action of a conventional loudspeaker. No one is going to be able to make a panel behave like a piston. One post that use ~12" square panels might do but is the gain worthwhile?
Dayton exciters. Some can come with rubber mounting spiders. More likely to dampen the panel than do anything else. Why? Others clearly show a hole on their rear side. Some state a thread size. Some look like they could be mounted on a hole in a rear separate panel. Somebody some where is using all of them otherwise there would be no point in making them. There is even a bass one not that it's performance on a 12" square panel, offset of course means anything useful.
NXT info
https://loudmagnet.com/html/pdf/NXT Technology.pdf
Where is the software to allow a panel to be evaluated?
jmproject,
I examined my measurements from the test I mentioned, to be sure my advice to you was good. Results shown below are a good summary of my findings. The SPL curves are all labelled with the panel width. As I mentioned before. it's the exact same panel every time, just with a few inches lopped off the width at each step. Note that with the full 24" width, there is a huge gap in the frequency response between about 40 Hz and 200 Hz. That's the reason I don't like the full 24" width. But notice how as the panel gets narrower, that gap in the frequency response fills in, and by the time you reach 14", there is no gap at all. Would a little wider (say up to 18") still be good? Maybe...
Here are a few other notes for completeness:
- Note that the lowest four curves are labelled with a "B", which stands for "braced". That's not referring to bracing of the exciter, but rather indicating that for those tests I added the center brace on the back of the frame. I knew from previous work that I wanted that brace there but forgot to add it until I had already cut down the panel to 18" (oops). Note the difference between 18 and 18B, which is that the addition of the brace helps to fill in the gap in the frequency response.
- Note the dip in response at 120 Hz, in all the curves. I have become pretty convinced by now that that dip is due to a "room mode", although I'm not sure I was fully convinced of that at the time I made these measurements as I am now. In any event, I wonder now if it's really necessary to go all the way to 14". That is, even as wide as 18" (with the brace), is arguably pretty good, if you are will to accept the argument that the 120Hz dip is due to the room itself rather than the panel. Looking at this data now, in retrospect, I'd be inclined to consider 16" before cutting down to 14".
- These results were measured before I got my new external USB sound card. I realized a few months ago that my PC's internal sound card had a built in filter that was cutting the signal below about 200Hz. So the overall bass response of each of these is likely better than these curves suggest.
Been also thinking about similar solution, but not sure if it is a good idea. If the exciter is not perfectly aligned it could create issues.
If manufacturer has designed and tested them without support and recommend using them like that, I would at least first test them properly mounted in accordance with their instructions. If that doesn't work I would make a warranty claim and then test if supporting them helps to avoid the issue.
Doing it the other way around could risk the warranty claim.
Sometime ago (if memory serves) someone posted the following YouTube video: Sheetcontrol - DML speakers, model Conundrum from Mescalito Speakers.
While this first video and the discussion around it didn't reveal much, it certainly intrigued me.
I just came across a second that reveals more: Sheetcontrol - тест 2 модели Conundrum
The discussion gives a description. Translated from the Russian (by ChatGPT) ...
Pretty sleek stands.
.
Looks like they mount the panels in two places on some kind of foam disks. Interesting.
Any thoughts? Analysis? Sources of this unusual looking "cardboard" or the stands?
While this first video and the discussion around it didn't reveal much, it certainly intrigued me.
I just came across a second that reveals more: Sheetcontrol - тест 2 модели Conundrum
The discussion gives a description. Translated from the Russian (by ChatGPT) ...
Also, the designer(s) claim they use cardboard panels, although the closeup of the edge doesn't look like any cardboard I've seen. Thoughts?
Pretty sleek stands.
Looks like they mount the panels in two places on some kind of foam disks. Interesting.
Any thoughts? Analysis? Sources of this unusual looking "cardboard" or the stands?
Hello Eric,
I am not in a period of a careful reading of the posts... Could you remind the height of this panel and the suspension method please ? The depth of the frame might be also a player.
Those experiments seem showing 3 points :
- the role of the brace (you have already posted about that)
- in addition of the LF roll off, the 14" panel is really smooth over all the band (less peaks)
- the 14" has a nicer LF roll off. Here, I am wondering if it is an effect of the panel modes or an effect of the front and rear waves combination. A possible test is to add some 5" "wings" each side of the 14" to come back to a 24" width and see if the smooth LF roll off remains. If yes, it is the result of the modes, if not it is an effect of the self baffling of the panel.
Christian
Quality post! 👍
My test of different sizes has been a lot less structured, and was focused on smaller dimensions. My perception has been that since the lower harmonics are more spread out, smaller panels will have a less smooth response in the lower mid.
But I guess that is not an issue with 14" and larger.
But I would expected the peaks to somewhat follow the same pattern as we see with the lowest peaks which follow the size of the panel. But to me it looks like above 150Hz the peaks no longer relate to the fundamental of the panel.
Hello Andreas
Yes interesting and elegant. This video
Example:
Take the stickers off the back of the drivers and compare:
https://www.billionsound.com/product/205.html and
https://www.alibaba.com/product-det...offerlist.normal_offer.d_title.51772f6aYgySDB
with
https://www.parts-express.com/pedocs/specs/295-230--dayton-audio-daex32ep-4-specifications.pdf
Even the AliBaba suppliers call it the 'Thruster'!
The same goes for almost every other Dayton exciter. Poke around a bit on the Billionsound site. All of the Dayton drivers come from that factory, and most of the specs are basically identical. I do notice that some of the Dayton drivers have plastic cups with supporting legs added to them, post-OEM. That could be because of sagging issues. Not sure.
So if you want DAEX exciters directly from the OEM, then the only requirement is that you buy at least 1,000 pieces at a time. There is no mention of licensing to Dayton (as there would be if Dayton designed the drivers.)
The NXT software was based on the ABEC/AKABAK software. Back in those days the NXT add-on was licensed, and you could not buy it without forking out substantial $$$'s. I think Tectonic Audio bought the rights before NXT went belly-up.
However, you can get a free version of AKABAK. https://www.randteam.de/AKABAK3/AKABAK-TechSpec.html
In my myopic opinion, it's worse than COMSOL interface-wise. I downloaded it a few months ago, but I've not had enough uninterrupted 'zone' time to figure it out. (About two weeks in a dark, locked cage with my computers and plenty coffee and a few protein bars should do it.)
I came to my conclusions based on things that the suppliers (Dayton and PE) do not address. From the interactions I've had with the retail suppliers, I suspect they are pretty much inexperienced and badly informed (Chinese-OEM >> English-Retailer communications could be at issue here.)
Magnet assemblies are heavy! A cloth spider cannot reasonably support big magnets especially when subject to large excursions. Visualise a voice coil at its excursion limit, but with a 100gram magnet hanging off the end of it. Many times per second.
The smallest, lightest drivers with small magnets only need adhesive tape on the voice-coil to support the whole driver. The adhesive and the spider support everything. No problem.
The medium-sized, heavier drivers have the addition of a plastic cup with supporting legs to support the magnet. The cups and legs are connected to the magnet assembly, and NOT to the voice coil. This is important. The weight of the magnet is transferred via the legs to the panel itself. This is a nifty solution. The amount of vibration from the magnet transferred through the legs is vanishingly negligible compared to the excursion and mass of the panel itself.
However, I generally strip off the cups and the legs and glue or screw the magnet directly to a supporting brace—Some of those magnets have threaded holes hidden by the plastic cups.
The larger drivers have M3 holes, most of them threaded, in the magnet assembly.
And the largest, heaviest drivers have M6 threaded holes in the magnet assembly.
High-efficiency drivers also have mounting tabs on their baskets. I ASSUME this is to accommodate a rear-mounting panel that fits over the whole magnet assembly, and that the mounting tabs are screwed directly into that rear panel. This makes the best sense from a design & ease-of-manufacture POV.
But it gets complicated... The main issue is the gravitational leverage (the mass) of the magnet supported by the voice-coil assembly: A large, deep ferrite magnet, which can handle only 20W, might need a threaded support; whilst a flat neo magnet might handle 40W but only with a cup and legs to support it.
It's all rule-of-thumb and indicative. Not Gospel.
Oh neat. I don't recall seeing that video. Concerning the panel material, in the video it looks to me like XPS, rather than cardboard, but that's just a guess.
Eric
Christian,
No that would be good, but it's a lot of effort! I have tested this speaker (or very similar) in the vertical orientation (posted responses are with the horizonal orientation), and with the speaker and mic at other elevations (closer and farther from the floor). Those tend to confirm that the 120 Hz dip is a room mode.
Eric