"In a dipole, the back wave is out of phase which leads to the low frequency roll-off. What is shown in the frequency responses of the article you linked is an in-phase delayed signal"
Understood. This is the source of my question. I have seen other people claim that having the DML panel close to the back wall reduced bass. I am wondering what the mechanism for this would be.
I just got some panels made last night with double wall polycarbonate panels and dayton 40w exiters. Now I have to figure out the placement and mounting/hanging.
Understood. This is the source of my question. I have seen other people claim that having the DML panel close to the back wall reduced bass. I am wondering what the mechanism for this would be.
I just got some panels made last night with double wall polycarbonate panels and dayton 40w exiters. Now I have to figure out the placement and mounting/hanging.
The best DML sound and experience I have ever heard was actually a pair of polycarbonate panels with Dayton 40W exciters (4 per panel) playing outdoors with absolutely nothing that reflects the back waves. I would therefore conclude that to replicate this unique magic DML sound experience in a room and with the panels close to the back wall, you will need to dampen / absorb the back wave as much as possible.
Others have done this before. I think @BurntCoil did before he built the Tall Blondes - putting thick polyfill between the panels and the wall.
Others have done this before. I think @BurntCoil did before he built the Tall Blondes - putting thick polyfill between the panels and the wall.
This is exactly what my dear wife commented on. She said it's the first time she'd heard music without being aware that it was playing through loudspeakers, She could pinpoint the instruments, but she said she could not "see" the panels with her ears. Of course, being a husband, I could make many manly and logical rebuttals to such a statement, but I took the compliment as intended.
+ @ajh
Yes, see the "London panel" from @BurntCoil in posts #761 and #993 610x1200mm 3mm thick Beech Ply 'Laserboard'
Christian
Please pardon me if this was covered somewhere in the 555 previous pages…..
I have a den I’d like to add Atmos to……but the wife says NO to holes in the ceiling for speakers. Ceiling is flat 8 feet high and 3/4” thick drywall. The attic is above this space so mounting exciters to the inner face of the drywall would be a fairly easy installation. Would this work for Atmos/height channel use?……content would require response from 90hz to 10khz.
Thanks for reading.
I have a den I’d like to add Atmos to……but the wife says NO to holes in the ceiling for speakers. Ceiling is flat 8 feet high and 3/4” thick drywall. The attic is above this space so mounting exciters to the inner face of the drywall would be a fairly easy installation. Would this work for Atmos/height channel use?……content would require response from 90hz to 10khz.
Thanks for reading.
Have you seen BurntCoil's offerings? In particular....
https://www.diyaudio.com/community/...ll-range-speaker.272576/page-340#post-7147457
https://www.diyaudio.com/community/...ll-range-speaker.272576/page-340#post-7147457
Clever thought & good thinking, but you wouldn't get useful output down to 90Hz with normal exciters.
Also, I think you could miss not having sound above 10K.
Ceiling speakers really are very unobtrusive & good > I think your wife is being very unfair.
Mayhem13.
I posted this guy some time ago.
He made a few videos on this subject.
I also made some recordings of an hdn8 exciter (not my favourite exciter, but it worked well on the wall) on this site somewhere.
It would be easy to experiment without damaging the ceiling ,if you have access to the loft.
I was surprised at the good full-range sound produced by this method.
He makes a few mistakes setting up his wall, but he is still impressed by the sound .
Steve.
I posted this guy some time ago.
He made a few videos on this subject.
I also made some recordings of an hdn8 exciter (not my favourite exciter, but it worked well on the wall) on this site somewhere.
It would be easy to experiment without damaging the ceiling ,if you have access to the loft.
I was surprised at the good full-range sound produced by this method.
He makes a few mistakes setting up his wall, but he is still impressed by the sound .
Steve.
I've had Warfdale loudpanels on our AR receiver for several months now. The backs are enclosed and panel semi rigidly mount along all edges. Exciters 2 and just supported by the panel. The panel is backed with ~25mm of fairly stiff foam. I'd guess just touching the panel but not freely floating. The foam has an oval cut out to clear the exciters. There are also a couple of pieces of light wadding, They are intended to be wall mounted and supplied with light weight stick on picture, not that any suite my tastes. Also the panels and frame are not far off a square - rather odd shape for picture frames. When used as fronts they have a subwoofer but they say they can be used alone for rears as heavy bass content will be lacking - I'd assume av receiver set for small speakers - the default or no choice on some. I'm currently using 2.5 anyway.
I bought them new a good while ago heavily discounted and used them as rears with a 5.1 system. Compared with a bought dedicated 5.1 system with their very convenient speakers they were no where near as good but there could be a variety of reasons for that not just the dispersion DML's have.
Listening tests. There is a DAB channel I listen to in the car. All ok. Same channel on the AV receiver noticeably NVG. BBC TV music broadcasts fine. Films - tricky. Certain speech can get distorted over a narrow freq range. Most noticeable on some USA females. Mostly pirate video via an H96MAX but official Amazon prime can be similar. I have wondered about the audio bandwidth via these codecs before. Better speakers may show this up. 5.1 is mass market with certain styles of speaker and lots of things are done in the AV receivers assuming that. I also don't like disturbing the neighbours. The dynamic range of a lot of films is a bit stupid for domestic use. Voice levels too low compared with that.
LOL Stereo definition. I suspect one of the speakers has a fault. They have a small overload protection device fitter and suspect one has gone awol or the AV receiver hasn't set itself up correctly. Both left and right go to the woofer and the panels are run off that. This could confuse the AV set up.
Had worry with a certain player's plectrum plucks. Sounded heavy. Compared with some others seems it was the player but more noticeable on dml. Most of the music I listen to is more complex than people post on here. That aspect doesn't seem to be a problem.
Mayhem13.
I found my post with the recordings and there are photos on the whole page.
Hope this is of some help.
Steve.
Thank you AjohnL
Below some pictures browsing on the net with "Warfdale loudpanel" search
The internal pictures are from oldschoolVlad posted in AudioCircle. I remember now the view of the crimping method of the exciter on the membrane.
When I bought them they were branded Warfedale PPS 1 Active Flat Panel Loudspeaker System. Same thing as Loud Panels effectively. It was relatively early on - press mentioning how they had been developed.
Not checked really but I'd suspect the panels are some mms thick, not really a membrane.. Panels on their own said to have an F6 of 80Hz. Crossover with the woofer 160hz. 20kHz stated as F6 as well.
I will try measuring the FR at some point but suspect that it wont work out well due to how they radiate. A cone speaker to some extent radiates like a point source, The "depth" of that is used in phasing calculations. or a time delay due to the same thing.
Not checked really but I'd suspect the panels are some mms thick, not really a membrane.. Panels on their own said to have an F6 of 80Hz. Crossover with the woofer 160hz. 20kHz stated as F6 as well.
I will try measuring the FR at some point but suspect that it wont work out well due to how they radiate. A cone speaker to some extent radiates like a point source, The "depth" of that is used in phasing calculations. or a time delay due to the same thing.
Good successful project ...
But judging by the microphone-sound of your voice, which is nice and clear in the ss's (sibilance)
it sounds like the dry-wall speaker only produces highs up to about 8Khz. There is lots of musical detail above this missing.
This is an example of why my upcoming DML project will include a super tweeter.
Just came across this post of mine with very close microphone recording.
I was having a little problem with the AVC but it came out quite well.
Steve.
Mister audio.
You have to remember that these recordings were made with me standing on a chair holding the exciter in my hand with a piece of wood screwed onto the exciter (see pictures).
The microphone on the first 2 recordings was at least 2m away with my hand and body and big head in the way.
The third recording was me still holding and moving the exciter around the wall ,but with the microphone in my other hand for a closer recording.
The hdn8 has a poor hf response above 10k ,I did make frequency plots of this exciter somewhere in this forum, mentioning that it was not my favourite exciter and had too much loud vibrating plastic .
But it seemed to work better on the wall than on the panels.
Plus I hope you were listening on good headphones for the best sound quality and not over speakers?
I keep forgetting to mention this 😃
Steve.
You have to remember that these recordings were made with me standing on a chair holding the exciter in my hand with a piece of wood screwed onto the exciter (see pictures).
The microphone on the first 2 recordings was at least 2m away with my hand and body and big head in the way.
The third recording was me still holding and moving the exciter around the wall ,but with the microphone in my other hand for a closer recording.
The hdn8 has a poor hf response above 10k ,I did make frequency plots of this exciter somewhere in this forum, mentioning that it was not my favourite exciter and had too much loud vibrating plastic .
But it seemed to work better on the wall than on the panels.
Plus I hope you were listening on good headphones for the best sound quality and not over speakers?
I keep forgetting to mention this 😃
Steve.