The posts on here fascinate me at times. Sometimes they reveal what a posters game really is. Especially if into carpets.
Anyway. I made a recording using a mobile phone of a commercial dml. Rather cheap when they were sold and liked by people who bought them. I have heard other commercial units in the past. What's changed is i can now measure performance pretty easily.
Mobile ~2m away. Panels 120mm tall. Posted it to someone who clued me up on using a mobile for this sort of use. I just used what was in the phone. Had a nose at app's and thought Dolby's would be the best answer but don't do some of the thing it can do. However I have a measuring mic and the the kit to use it so will use that in the future and post sound files. No interest in recording stereo. If mono is fine from a speaker that will look after itself other than radiation pattern differences.
I have no idea where the clicks come fromRemember 120mm tall. The frequency response is extended via a rather simple volume control on the woofer. It needs a tiny touch of that to get all of her voices lower register.
So I'm interested in 2 way. There is a youtuber that goes all of the way through constructing some fairly large ones. He even demo's them and most of the music he plays is similar to what it posted on here. Then come a famous female pop singer. My feelings - a rather crap mix. Maybe he recorded it and those can crop up even live. How did he have his tone or whatever controls set? Or is it the speakers.
I have a very simple, yet specific question about the Dayton Audio DAEX25FHE-4. Usually - from an engineering perspective - such a device has a spec sheet listing various parameters and Dayton has provided such in .pdf format.
The words I'm looking for are "may be mounted in any position" and I'm not seeing that in the spec sheet. So my question is, can I mount this device - hanging solely off the pre-applied 3M adhesive on its piston head - in any position?
I would think so for a static (not mobile) install. I'm sure it's done vertical all the time and an easy assumption that Dayton is OK with that, regarding thing like failure, warrant, replacement etc.
The words I'm looking for are "may be mounted in any position" and I'm not seeing that in the spec sheet. So my question is, can I mount this device - hanging solely off the pre-applied 3M adhesive on its piston head - in any position?
I would think so for a static (not mobile) install. I'm sure it's done vertical all the time and an easy assumption that Dayton is OK with that, regarding thing like failure, warrant, replacement etc.
Not quite sure what you mean by that.
But the magnet on that device does have have a hole in it with an M3 thread that seems to go all the way through to the other side of the magnet.
I prefer to mount drivers like that with a screw to a back brace for reliability issues. It makes almost no difference to the sound.
Thanks for replying so quickly. What I mean by that is, if I stuck it to the side of a closet door (example...) would it hang on there for 5 - 10 years with no issue - aside from perhaps the adhesive drying out?
I want to know if this device was designed to hang off a vertical surface, versus a horizontal one. Placing it on a wall is very different than the bottom of a desktop. Hence "may be mounted in any position" is what I'm looking for confirmation of.
Or "frame / magnet structure must be independently supported, square to adhered surface, regardless of orientation" which is a very different statement.
Dayton makes neither, from my quick look. I'm just wondering if anyone here knows and can share.
Exciters in itself is basically a flawed design as they rely on a heavy plastic voice coil to support the magnets weight as well as the diaphragm. Eventually in time depending on how heavy the diaphragm you are using could cause voice coil sag which in turn will damage the exciter. To fix this problem a support/spine is needed to hold the magnet in place while a frame with a surround material is used to support the diaphragms weight very similar to the way a conventional cone driver is built/supported.
Last edited:
yes, this in a nutshell .................. @Audiofrenzy, could you share what your favorite exciter is?
Last edited:
So, what if the diaphragm holds the exciter, instead of the exciter holding up the diaphragm? Do they have a measurement of how many oz the VC can hold without sagging? How does that compare to the weight of the whole thing?
The implication of the 3M attachment material is that it's a "Stick 'n Go" product. A table top, your bedroom closet door, a bathroom mirror. Or a DML speaker with one of these stuck on the back, verticle panel.
I'd like to be able to just hang it off the peel-off attachment, rather than explicitly brace the magnet structure back to the frame that holds the diaphragm. Use it in "momentum mode". I have to believe this is done all the time; why in post #1 a panel is shown with a pair of transducers simply attached. Other designs I see have structure to hold the magnet assembly fast. Was that an afterthought, improvement to "nothing" - or absolutely necessary?
@jjasniew
Without the adhesive you will get bad distortion as the exciter will hit against the plate instead of moving with the plate, so it is not only to hold the exciter up. Sagging happens with time, heat and high levels. For low powered applications you might get away without it for a long time I would guess.
Without the adhesive you will get bad distortion as the exciter will hit against the plate instead of moving with the plate, so it is not only to hold the exciter up. Sagging happens with time, heat and high levels. For low powered applications you might get away without it for a long time I would guess.
I don't think Dayton intend for them to be used any other way. They do a model where the part that is stuck on remains and the rest can be changed. Conventional loudspeakers eventually have support problems. How long do exciters last - good question. One that needs an answer.
My dad's AR's took ~20years well known for eventually having support problems.They are effectively working via their own inertia.
The screw hole is there on some models but covered. Mounted that way they are working in push pull mode. They have limited travel and some natural relaxed position within that, Some care will be needed to avoid stressing the panel if they are mounted this way. Their point of resonance is unlikely to be the same as mentioned in Dayton's spec.
The weight of the exciter may permanently deform the panel. Odd way of putting it but if the deformation exceeds the yield limit that's the best way to describe it. However it will deform the panel to some extent.
The other question is just how did companies produce kit under the NXT patent that sounded good. Exciters or group of them stuck on and central as far as I am aware. Also panel rigidly or at least semi rigidly mounted edges thoroughly damped either way.
Last edited:
Jokingly why not design your own then. I'd see as more of an as they are probllem. They may be improved by use of better materials or a brand new invention - directional anti gravity for instance. Use of plastics is an odd area. It can result in lighter and effectively strong enough compared with metals. Better in other respects as well.
Your post reminded me of an interesting youtuber who decided to make an exciter from a loudspeaker using nuts and bolts and applied it to a horizontal glass table. It's interesting as it wouldn't be difficult to do this more "poshly". Bright bloke though down to what else he did. Rather rigid table so no sound. So he places a weight on it and lo the music plays. His exciter can't deform the glass only deform the deflection caused by the added weight. Not that it means panels should be made this way but it does indicate something about the characteristics of the material needed.
That video I posted. It surprised me how well the reproduction of the speakers survived the recording method and the route to youtube and back through my PC speakers which aren't as good as I have used but are ok in their range. The panels within their range sound better. Usual reason - what I would call clarity.
Hi AudiofrenzyYou can get free high density EPS from your local food store as some fruits like grapes are shipped in these EPS containers. Most times they just throw the old containers away. View attachment 1176431
Not to mention that the carpet enhances the EPS.
On a serious note there are indentions from the letters and smaller circles which need to be sanded down for a flat even surface. I hate sanding EPS as it gets all over you as the fine dust particles can be dangerous if inhaled as it can damage your lungs so a good mask and eye protection is required.
What is the biggest difference between "polished" and "unpolished" surfaces?
Hello Audiofrenzy,You can get free high density EPS from your local food store as some fruits like grapes are shipped in these EPS containers. Most times they just throw the old containers away. View attachment 1176431
Not to mention that the carpet enhances the EPS.
On a serious note there are indentions from the letters and smaller circles which need to be sanded down for a flat even surface. I hate sanding EPS as it gets all over you as the fine dust particles can be dangerous if inhaled as it can damage your lungs so a good mask and eye protection is required.
What about starting a series of some posts to describe how to transform this EPS container in a more than decent DML (not the beginner's model)?
I got some EPS (clean!) containers from the fishmonger near my home. The first evaluation of the density shows more a low density than high density.
Which density is this one?
Christian
Ahh, now I see what you mean by 'push-pull'... But do you really think that some designers here would operate the exciters in 'push-only' mode (with a back-brace without adhesive?).
I always assume that the voice coil is glued to the panel so that it can push AND pull on the panel, but not necessarily support the full weight of the magnet for an extended period, hence threads which accept nuts and bolts.
Granted, these drivers employ the latest space-age designs using lightweight, highly efficient, highly optimized solutions and materials and technologies that have never been seen before; but still, there are basic universal limitations that cannot be surpassed in this Universe. I would assume that the maximum performance would be delivered by very high BL, relatively low Mms, but not infinitely low reactive mass. As in any perfect engineering solution, there are always compromises.
I wouldnt call it a favorite nor do I just have one favorite but more of what is right for a certain application/design as I have around 15 different designs all good in there own right. Some of my exciters are not from P.E. but from Chinese knock offs that sound just as good as other exciters but at 1/4 the price. Even Spedge has these Chinese knockoffs. Heck most of P.E. exciters come from China so they are not much different.
Even if the diaphragm holds the exciter, the magnets weight over time can cause sag and even more so with the larger exciters with large magnets. No so far I havent seen any measurements of how much a VC can hold without sagging but I would assume its not much as a voice coil is thin and not strong enough.
Yes you can just use the exciters as intended and just stick it to any surface. Its just that over time the VC can start to sag depending on the size of the exciters and the smaller exciters wont sag as much due to having a lighter magnet. The culprit is that there is nothing to support the weight of the magnet. Also without support the magnet will rattle at high excursions due to the momentum of the magnet moving back and fourth. A brace/spine does 2 things it prevents voice coil sag and prevents the magnet from rocking back and fourth. This is the reason I say exciters are basically a flawed design to begin with and this is also the reason why NXT/Tectonic developed the BMR driver even though its nothing new as it has been done before by Bertagni who did it in the 70's.
You dont have to design/build your own exciters you just have to modify the existing exciters by simply adding support to the magnet as well as the panel diaphragm just like a conventional cone driver or BMR driver.....I agree better/lighter/thinner materials will add improvement the problem is they are not readily available as most of us do not have access to that kind of resources. One of the main problems is finding the ideal material for the diaphragm.
Yeah I seen that video. At the end it would of been better to just buy a exciter.
Yeah those cheap small speakers are most likely licensed by NXT as NXT lent out there patent to certain companies like TEAC with there small DML speakers with a conventional powered subwoofer.
I assume polished means sanded? This only pertains to EPS material.
If you look very closely at any EPS material you will be able to see the tiny beads all bunched together. You have to lightly sand the surface until you no longer see any of the beads, instead it will be one uniform surface.
If you look at XPS you will not see any beads bunched together but rather one uniform surface.
EPS material is better then XPS because the beads make it easier for the vibrations to penetrate through the panel due to gaps between the beads. The problem is the surface of EPS needs to be one uniform surface which is why it should be sanded.
So when both sides of EPS are sanded they will have a uniform surface like XPS while in the middle core of the EPS will still have pours beads for the sound to travel through more easily.
I dont know exactly the density of the EPS container but when I compared it to my high (3lbs) density EPS sheets they seem pretty similar in density.
1. High density EPS (3lbs)
2. 1/2inch thickness.
3. Sand both sides of the panel surface lightly enough so that you no longer see the beads. Start with 100 grit and smooth with 220 grit.