Ummm... Speaking for myself, that is not quite what I was getting at. I was not asking about room modes or boundary interactions. I was asking about the radiation pattern of a rectangular DML in free space, and whether dispersion differed significantly in the vertical vs horizontal direction for a given orientation. I also gave the example of a line array which clearly has a non-hemispherical radiation pattern.
From what others are reporting here, and looking at the polar response plots for Tectonics, the orientation of a DML does not seem to matter much for SPL or frequency. That is different than a cone driver in that a given cone tends to beam at higher frequencies for example.
Correct me if any of the above is wrong.
From what others are reporting here, and looking at the polar response plots for Tectonics, the orientation of a DML does not seem to matter much for SPL or frequency. That is different than a cone driver in that a given cone tends to beam at higher frequencies for example.
Correct me if any of the above is wrong.
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You are right, orientation has no effect on SPL or FR. other factors will like size of the panel but not orientation
Earbourne, I recommend that you try 3mm poplar laserply from Plyco.
I've tested what you've used, and I am 100% sure that you'll find the ply far superior to the MDF and Masonite
Eucy
Deude,
In case you hadn’t noticed, this thread is kind of like the wild West. In other areas of the DIY from it’s pretty easy to tell who the expert is but in this thread not so much.
DML is a much newer field. No good models exist. Mostly there’s a lot of speculation.
On the plus side, you can make a pretty decent speaker without any real knowledge.
Good luck.
Eric
In case you hadn’t noticed, this thread is kind of like the wild West. In other areas of the DIY from it’s pretty easy to tell who the expert is but in this thread not so much.
DML is a much newer field. No good models exist. Mostly there’s a lot of speculation.
On the plus side, you can make a pretty decent speaker without any real knowledge.
Good luck.
Eric
I suspect Eucy is correct. At the very least with respect to efficiency. MDF is really heavy and hence its efficiency is poor.
I think you will find many kinds of plywood to be better certainly at least with respect to efficiency.
Eric
Hi Eucy , thanks for sharing.
It wont hurt for me to try them and compare both MDF and poplar ply side by side.
I have it on my back-of-envelope notes to one day to also try out a system i saw posted here sometime back of vacuum bagged carbon fibre over 2mm or 3mm Balsa.
I have plenty of capacity to learn new things here.
You couldn't detect the difference because you weren't watching! This is important.
Some of the experts here insist that they use "only their ears" when in fact it's their eyes that cause them to "hear" differences...
I use my mostly-vertical panels in lighting trusses. This means I can mount them horizontally when I'm running a lighting rig too.
As far as dispersion and audience coverage is concerned, there's zero difference.
I think it's an intimate and often stubborn misunderstanding of DML principles that makes some people think that DML panels operate the same as point-and-spit cone speakers.
In a listening room, I would think that any sensible proportions will be very hard to distinguish. The proximity to eventual walls or ceiling will change marginally, and I think you would need a very extreme scenario to notice any difference.
For PA applications if you have a large installation with many plates and large distances between stacks, it would matter if you spread the panel arrays vertically or horizontally and with what spacing, but I think how each plate is oriented would be very unlikely make any noticeable difference.
I place them vertically since I rather get more height than width for the stack because it fits nicer over the subs and helps to project the transients more directly to every listener. And it just seems weird to place them horizontally with extra space between them instead.
For PA applications if you have a large installation with many plates and large distances between stacks, it would matter if you spread the panel arrays vertically or horizontally and with what spacing, but I think how each plate is oriented would be very unlikely make any noticeable difference.
I place them vertically since I rather get more height than width for the stack because it fits nicer over the subs and helps to project the transients more directly to every listener. And it just seems weird to place them horizontally with extra space between them instead.
Indeed!
I find the horizontal placement amongst the lighting, makes the speakers "disappear" visually. The audience cannot see where the sound is coming from because the panels don't look like speakers. And I have heard comments exactly what you have experienced, that people say PA system sounds like giant headphones.
The braces in a guitar or violin or piano, or almost any other acoustic instrument, are shaped in such a way as to completely kill the reflections from the end of the brace.
Note that those braces are applied directly to the vibrating panel.
I've seen experiments (I cannot locate the videos! 😭) where an aluminium square rod, cut off square, will ring like a wind-chime when struck with a hammer.
But when shaped to look like the guitar braces above, the same size bar does not ring at all. It's completely dead! Like a piece of soft wood. I've messed around with braces shaped like this extending from the drivers to the panel edges, but did not spend enough time to get conclusive results.
Those spines or supports not touching the panel, attached to the frame, are used for supporting heavier drivers (with M3 or M6 threaded holes in the magnet under the stickers) because of the voice-coil sag factor. Smaller drivers will have plastic legs to support them, and the smallest drivers depend only on the voice-coil adhesive and the strength of the spider to support them, and don't need anything else.
Larger magnet/driver structures usually resonate at extreme low frequencies (10-35hz depending on the weight of the magnet and the stiffness of the spider material) and it actually makes no measurable nor aural difference whether they are supported or not—DML panels rarely perform well at sub-bass frequencies. I prefer to fix the magnet to a spine whereby I can limit the excursion of the panel and get control of the panel movement at low frequency and high SPLs (+/-3mm @100Hz). This would be analogous to blocking the port on a vented speaker cab to limit the speaker cone excursion below port frequency (usually around 45Hz) to prevent the cone tearing itself apart at high SPL.
One day, that carpet will fall (or lift, or shift) and reveal all!!
What awaits us ..oh the suspense! 😱🤗💥💥👏👏
For all the audio info that a cell-phone recording can deliver (almost nothing???) I wonder why he doesn't show us what his panels look like.
I'm guessing because they are nothing special or new and the grandeur of some day patenting them and making island buying $ off it.
Listening to someone else's recording sounds only as good as your stereo setup of course. It's like someone making a commercial and trying to sell you a 4K TV while you may be watching it on your grandfather's POS 720p.... "Just look at how clear and bright these colors pop!".
Thats why I wont give out my designs because my DML designs are nothing special or new.
The ironic part is most of you dont believe or listen to what I say anyway so whats the point. I mean it only took yawl around 3 years to figure out that what I said about foam/damping as well as a frame and spine was true.
We all live in different parts of the world so for anyone to hear ones gear in person is most likely not going to happen. All recordings are someone elses recordings. One of the main goals in audiophile sound is to recreate as close as possible to a LIVE show/band playing.
The better the recording the better one will be able to retrieve micro details. My cell phones mic is not that good as my cell phone is the bottom of the line. Heck even Spedges cell phone is better then mine because I can tell by his recordings. With todays technology our recordings can rival professional recordings.
Any ways I think I will follow Spedge and lay low and let all you Gurus handle this DML thread.
The ironic part is most of you dont believe or listen to what I say anyway so whats the point.
I mean it only took yawl around 3 years to figure out that what I said about foam/damping as well as a frame and spine was true. We all live in different parts of the world so for anyone to hear ones gear in person is most likely not going to happen. All recordings are someone elses recordings. One of the main goals in audiophile sound is to recreate as close as possible to a LIVE show/band playing.
The better the recording the better one will be able to retrieve micro details. My cell phones mic is not that good as my cell phone is the bottom of the line. Heck even Spedges cell phone is better then mine because I can tell by his recordings. With todays technology our recordings can rival professional recordings.
Any ways I think I will follow Spedge and lay low and let all you Gurus handle this DML thread.