This single sheet of ply, cut exactly in half will be my 2 x 'floor-base plates'.
As you probably notice, I am going to be using standard lengths for minimal cutting.
This way, it may be a simple project for many to copy.
(correction: the space between the panel sides and side walls will be 10mm)
As you probably notice, I am going to be using standard lengths for minimal cutting.
This way, it may be a simple project for many to copy.
(correction: the space between the panel sides and side walls will be 10mm)
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The woofer I have chosen is >
https://www.electusdistribution.com.au/store/category/379/product/cw2199.aspx
https://www.electusdistribution.com.au/store/category/379/product/cw2199.aspx
This is from a pdf he wrote:
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The next task is to design the woofer section, and here the design philosophy will be slightly different. The woofer will be operated completely below the dipole peak, and the dipole loss can be significant unless the driver or baffle is large. On paper it seems that a large format pro audio driver would be especially well suited for this task, however, listening tests on loudspeaker prototypes constructed during 2021 revealed that most PA drivers 15 inch or larger have audible energy storage or resonance problems as low as 250 Hz. The larger 18 or 21 inch class driver that would be most suitable for reducing dipole losses are worse in this regard. Instead of a single large driver the woofer section can be comprised of multiple home audio drivers of a smaller diameter (e.g. 8 to 10 inch size) mounted close together on a baffle. Unlike a single large driver, the smaller drivers have no inherent response anomalies at the upper end of the intended passband. The woofer panel approximates or exceeds the front to back pathlength of the larger single driver, which further minimizes low frequency losses.
.............. Despite all the advantage of using multiple drivers mounted in a small baffle, the woofer panel should not be operated to an arbitrarily low frequency. The drivers will be operating in close to “free-air” conditions, meaning that the near-resonance response will be drooping well above Fs if Qts is not relatively high. When combined with the dipole losses, this causes the SPL loss rate to increase beyond 6dB/oct and the power required to sufficiently equalize the response increases rapidly. Just like with the midrange, low frequency distortion is magnified, and it is important to use high-quality drivers that have very low distortion below 200 Hz. Even if these problems are mitigated by using special high-excursion, high-Q drivers or larger folded baffle arrangements, dipole bass systems tend to be effective only above 30 Hz in most domestic settings. For these reasons, I choose to add another band to the loudspeaker, e.g. a subwoofer. To reduce the overall demand on the drivers in the woofer panel, it is prudent to cross over between the subwoofer and the woofer panel around 80 Hz.
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Charlie offered the full article in this post:
https://www.diyaudio.com/community/...sion-re-live-edge-dipoles.401432/post-7458909
Dolby do a free app. It will do all sort of thing but a quick look indicated that can also be nothing - just record. I've no need of recording at the moment but will look further when I do. On android I'd look for add free packages. There are still people around that don't see this area as a money pit and the apps are often pretty good.
Hi Christian.
This is the recording app I use.
It was the only free app I could find that does not have automatic volume control permanently on !
The apps use the top and bottom microphones ,the top is the left microphone.
In my room I find the optimum distance from the panels to be about 1m .
To find this position I moved the microphone from the seating position to the panels until the room noise minimised.
You could also point both panels facing each other and hold the phone directly in-between the two, this will give you just the sound of the panels, this gives you the impression of waring headphones.
When videoing without the app, my phone camera automatically videos in stereo, which I have posted on YouTube .
Steve.
https://www.google.com/search?ie=UT...s&source=android-browser&q=lexis+audio+editor
This is the recording app I use.
It was the only free app I could find that does not have automatic volume control permanently on !
The apps use the top and bottom microphones ,the top is the left microphone.
In my room I find the optimum distance from the panels to be about 1m .
To find this position I moved the microphone from the seating position to the panels until the room noise minimised.
You could also point both panels facing each other and hold the phone directly in-between the two, this will give you just the sound of the panels, this gives you the impression of waring headphones.
When videoing without the app, my phone camera automatically videos in stereo, which I have posted on YouTube .
Steve.
https://www.google.com/search?ie=UT...s&source=android-browser&q=lexis+audio+editor
Christian.
Apart from Audiofrenzy , all other recordings I have heard have been very poor and too far away from the panels.
When you record from your listening position you are mainly recording the room, which the microphone pics up far too well, over emphasising this problem.
It sounds like you are recording in the bathroom.
Our ears seem to automatically ignore these in room reflections ?
The recording should sound very similar to the recording on the CD.
If not, you have a problem.
The actual in room sound will obviously always sound far far better than the panels recordings.
The panel recordings give you the worst case scenario, so if they sound very close to the CD sound, you know the in room sound will be even better.
I hope this helps.
Steve.
Apart from Audiofrenzy , all other recordings I have heard have been very poor and too far away from the panels.
When you record from your listening position you are mainly recording the room, which the microphone pics up far too well, over emphasising this problem.
It sounds like you are recording in the bathroom.
Our ears seem to automatically ignore these in room reflections ?
The recording should sound very similar to the recording on the CD.
If not, you have a problem.
The actual in room sound will obviously always sound far far better than the panels recordings.
The panel recordings give you the worst case scenario, so if they sound very close to the CD sound, you know the in room sound will be even better.
I hope this helps.
Steve.
Re. my DML project >
I have finally decided
to make my panels 1200mm x 1200mm square.
This will decrease moving mass and improve transient response, plus
it will also make the whole project a far more reasonable size.
Two pieces of this timber, both cut diagonally will give me my four 'shallow triangular side walls'.
I have finally decided
to make my panels 1200mm x 1200mm square.This will decrease moving mass and improve transient response, plus
it will also make the whole project a far more reasonable size.
Two pieces of this timber, both cut diagonally will give me my four 'shallow triangular side walls'.
It sure is >
It's what I call 'tight budget but good spec.'. I have used the 8" version previously
with quite astonishing results - super fast & tight, with no upper end ringing. (pre XO)
I just bought my 12" pair this afternoon and I'm getting a tad excited
The first monopole shape is the main air mode, the sum of the air volume the soundhole and flexibility of the box. The second and third I belive is the main top mode split into two peaks by coupling to another resonance.
I just tested my hearing. Its top end is 4525 Hz, the same as my tinnitus sound. It's odd that when I tested it last year, 7445 was the top end, and sounded the same as the 4400 sound does now. I wonder why. That's probably why the coke can lid did not add to the quality of the sound, because I couldn't hear that high. Maybe if my hearing drops just a little lower, I won't be able to hear my tinnitus. That would be great!
Hello MisterA
I'm still having a hard time envisioning your design. Do you think you could make a rough sketch to help explain it?
Thanks,
Eric
Regarding the (lack of) support for the exciter, that doesn't sound like anything I've heard before. Can you explain more what you mean? Is this something you have read somewhere? Or discovered yourself?My original thoughts on the subject was to obviously create a rigid/firm structure securing
the chassis of the exciter from movement >
But, somehow, by some twist of motional physics, you get more efficiency & better sound
without such a thing. It's more about how you control the panel itself
What do you mean by "control the panel itself"?
Thanks
Eric
Hi there,
Although the timber structure is very simple, it doesn't lend itself to easily written description.
I wish I was one that could draw/sketch in 3D. I will try to attempt to make a sketch and post it
( I will post stage by stage photo's as the project proceeds. I'm not a very 'quick build' person )
After all the videos (a lot) I have seen regarding - building, listening & testing DML's, it is apparent that
all the best results come from 'freely attached' exciters. Even Dayton suggests simple mounting.
One video I saw, compared, in large open space, 5 different panel designs - hanging freely.
The panel with a solid steel tube securing the chassis of the exciter from movement, actually had the
worst sound and also (surprisingly) lower efficiency output level. I have to go with what has been demonstrated.
Regarding "controlling the panel itself" > My design will at 'panel top' hang by 2x synthetic strings as usual,
but, I am not going to just leave the panel bottom hang freely. Because my DML panel is not being designed
for any 'active bass' of any kind, my design will have a form of rubber suspension thereby creating a natural
low frequency roll-off. IE. raising Fs & reducing LF. distortion - to be further augmented with a second order filter.
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I got low energy health issues, and I just checked and today, with low energy, I'm topped out at about 6,500 hz, some days I can hear up to about 10 khz (with my good ear...lol) so I never related it to my energy levels, but thanks for getting me to think about this.
It still surprising just how lovely music can still sound with reduced range
Hearing mechanism seems more complex than a question of bandwidth.It still surprising just how lovely music can still sound with reduced range