Leob.
the type of exciter and panel mounting used by tectonic probably helps with efficiency ?
forcing the the panel wave at the lower end of frequencies as well as maybe getting rid of suck outs ?
as mentioned in the tectonic vidios, they also expand the central primary driving area by using 4 drivers.
so that the primary driving area is not just a small area around the single coil but the whole area between and slightly beyond the 4 exciters.
Steve.
the type of exciter and panel mounting used by tectonic probably helps with efficiency ?
forcing the the panel wave at the lower end of frequencies as well as maybe getting rid of suck outs ?
as mentioned in the tectonic vidios, they also expand the central primary driving area by using 4 drivers.
so that the primary driving area is not just a small area around the single coil but the whole area between and slightly beyond the 4 exciters.
Steve.
Actually to be specific, as I understand sensitivity is typically measured as 1w at 1m. Efficiency is a bit harder to measure, but they do go through in to it in one of the videos. To measure efficiency you would need to measure lots of different points in a sphere around the speaker. Obviously a DML becomes far superior when it comes to efficiency, however it is both complicated to measure and although sensitivity ignores what is a big advantage of DML, efficiency is is typically not so useful to measure either since usually one cannot really make any good use of the sound radiated backwards.
So maybe no need to measure the whole sphere around the speaker to get the true efficiency, but certainly more than one location needs to be measured to give a good idea about the performance of a DML.
Just got a measuring mic and carbon filament, so gonna do some experimentation!
Don't have a SPL meter to calibrate against, and not sure how to calibrate against a known speaker. Are you thinking to it based on their sensitivity rating? Unfortunately I cannot find a rating for the speakers I have.
So maybe no need to measure the whole sphere around the speaker to get the true efficiency, but certainly more than one location needs to be measured to give a good idea about the performance of a DML.
Just got a measuring mic and carbon filament, so gonna do some experimentation!
Don't have a SPL meter to calibrate against, and not sure how to calibrate against a known speaker. Are you thinking to it based on their sensitivity rating? Unfortunately I cannot find a rating for the speakers I have.
Leob.
with dml ,You have to think about what you are saying.
The sound from the back and sides of the panels ,is reflected back towards the listener, or audience.
But you also get a direct radiated sound in those back and side positions.
In the 70s I went to see steeleye span play at our local town hall.
This had a large rap around balcony ,so we were sitting above the band,with a great view of the band.
But the sound was very bad as we could only hear the echo from the rear hall wall.
They had small personal monitors facing them so they could hear what they were playing and singing.
If they had had a couple of tectonics panels they could have covered every area of the hall ,even in our position.
And they would not need the small monitors facing them.
Perfect sound all around.
Steve.
with dml ,You have to think about what you are saying.
The sound from the back and sides of the panels ,is reflected back towards the listener, or audience.
But you also get a direct radiated sound in those back and side positions.
In the 70s I went to see steeleye span play at our local town hall.
This had a large rap around balcony ,so we were sitting above the band,with a great view of the band.
But the sound was very bad as we could only hear the echo from the rear hall wall.
They had small personal monitors facing them so they could hear what they were playing and singing.
If they had had a couple of tectonics panels they could have covered every area of the hall ,even in our position.
And they would not need the small monitors facing them.
Perfect sound all around.
Steve.
Outdoors it wasted energy anyway. Unless the speakers are in the middle of the crowd, sound reflected backwards might not always be completely useless, but will be a lot less valuable that sound emitted forward. It might not be as problematic with a DML as it would be otherwise when you have proximity to a back wall, but still not as useful as sound radiated directly to the audience.
I would say that to get a practical efficiency it would depend on the application what you should measure.
There are some applications where 360 degrees of dispersion are desirable........ I am in the middle of building a PE Executive kit and I kind of want to do a DML + OB setup instead since I will be using it outside. Getting the same sound all over my yard as I chase my kids around would be nice.
I think 1 measurement on axis is OK for comparative purposes though. Yes DMLs have better dispersion but I imagine many of us are listening from fixed positions. So the W/SPL at that point is the main thing from a practical standpoint.
I think 1 measurement on axis is OK for comparative purposes though. Yes DMLs have better dispersion but I imagine many of us are listening from fixed positions. So the W/SPL at that point is the main thing from a practical standpoint.
Tectonic also use different size panels 378x 478 and 400x575.
Leob.
As in this video you can stand behind the band or DJ and not miss out on the sound.
Maybe having the pa in the centre sometimes could be an advantage ?
I have a 200ft long garden .
If I set up my pa at one end of the garden the sound would have to travel 200ft to reach the people at the back.
But only 100ft if I placed the pa in the centre?
Even less if the area was square or round ?
just a thought.
Steve.
Leob.
As in this video you can stand behind the band or DJ and not miss out on the sound.
Maybe having the pa in the centre sometimes could be an advantage ?
I have a 200ft long garden .
If I set up my pa at one end of the garden the sound would have to travel 200ft to reach the people at the back.
But only 100ft if I placed the pa in the centre?
Even less if the area was square or round ?
just a thought.
Steve.
Hello Steve
You are right. All what I mentioned before ignore the role of the force factor Bl of the exciter; ie bigger magnet.
Yes, could be an advantage sometimes, but very rarely. Especially considering that you then have to have the panels at the same height as audience and without tilt to make use of the backwards emissions.
Typically you have a room with seating positions in front of speakers or a crowd in the middle between speakers, but for installations and sparsely populated spaces it might be a nice idea sometimes.
We always surround the dancefloor with speaker stacks, so in your example say you either have a square of panels in the middle or one in each corner of the dancefloor. If you ware in the middle of the dancefloor surrounded by stacks you would have 4 panels directed at you 100m away from each direction the way we set them up. If speakers are in the middle instead and you are at the edge of the dancefloor you will have a lump of panels from one direction, also 100 m away.
This is one of the reasons that I really like to try making DML PA...most audio pros will frown at using multiple speakers pointed at each other due to the inconsistent sound over the dancefloor with phase and timing issues, but I think it is worth having four stacks for the immersive experience anyway. DML not only provides more immersive sound in general, but also seems better suited for that kind of setup.
I was just looking at the tectonic animation of the dml panel again.
they are really pushing the panel animation to its limits and beyond ?
The 4 edge restraints and the foam (or rubber ?) Strips are bottoming out badly.
especially on the two opposing corners , but not the other two corners.
this could be the orientation of the exciters , I presume there are two of more exciters used for this animation.
They obviously wanted to show the dml movement more clearly, similar to the piston animation.
The tectonic speaker design will cause more whiplash in the corners than our designs, but they still do not round the corners ?
Probably because under normal working conditions the whiplash is not a problem , and may lower the fundamental resonance a little ?
Steve.
they are really pushing the panel animation to its limits and beyond ?
The 4 edge restraints and the foam (or rubber ?) Strips are bottoming out badly.
especially on the two opposing corners , but not the other two corners.
this could be the orientation of the exciters , I presume there are two of more exciters used for this animation.
They obviously wanted to show the dml movement more clearly, similar to the piston animation.
The tectonic speaker design will cause more whiplash in the corners than our designs, but they still do not round the corners ?
Probably because under normal working conditions the whiplash is not a problem , and may lower the fundamental resonance a little ?
Steve.
Steve,
I'm sure they are not truly pushing the panel to the extent that the animation shows. They just exaggerated the displacement to show the movement more clearly, as you sugggested. Finite element programs provide a scaling factor you can adjust to any level you want, and if you overdo it, it can give the appearance of things happening that really do not. If you really exaggerate the displacement, for example, it makes the plate look like an elastic membrane that stretches, even though it does not. I'm sure this is a similar case.
Eric
What do you mean by "our designs" ? Hanging from strings? Not all of us do that.
I recall that the "Tech Ingredients" guy suggested rounding the corners, and I have read the assertion by some that rounding the corners is helpful because it "reduces reflections" or something like that. But that is simply not correct. No matter how rounded the corners are, or how parallel (or not) the panel edges are for that matter, there will be reflections, just like for a perfectly rectangular panel. Damping the perimeter can reduce reflections, but rounding the corners will not.
I do suppose it's possible that if the corners are "too free" maybe you could get an effect kind of like chuffing in a bass reflex if the port is too small. But that seems far more likely for a plate hung from strings than for the Tectonic one that apparently has constraints not too far from the corners.
Eric
Eric.
The problem is ,you think you have made a tectonic panel clone, you have not .
I only know this as I spotted the same methods I used years ago on a couple of my panels.
they tried to hide it well, but they made a mistake when they posted the spec sheet you posted.
which is different from the ones they show now.
as soon as I saw it I knew.
it's sort of a rehash of the 1960 patent I posted ,with a slight twist , well massive twist actually.
it would have been simple to implement on the that patent but probably without the extended low frequencies ?
I used a similar method to tectonic on a 12inch eps ceiling tile , which worked very well, but I just prefer free floating dml panels, so that was that.
But I see how they could work well with a tectonic type panel.
Steve.
The problem is ,you think you have made a tectonic panel clone, you have not .
I only know this as I spotted the same methods I used years ago on a couple of my panels.
they tried to hide it well, but they made a mistake when they posted the spec sheet you posted.
which is different from the ones they show now.
as soon as I saw it I knew.
it's sort of a rehash of the 1960 patent I posted ,with a slight twist , well massive twist actually.
it would have been simple to implement on the that patent but probably without the extended low frequencies ?
I used a similar method to tectonic on a 12inch eps ceiling tile , which worked very well, but I just prefer free floating dml panels, so that was that.
But I see how they could work well with a tectonic type panel.
Steve.
Eric
In this post about your full balsa panels, you explain how you glued them : PVA between each board of the same layer, spray adhesive between layers. Which kind of spray adhesive is it? Sorry if the answer seems obvious... My knowledge about the different types of glue is weak.
Christian
Leob
Being back home, I watched more carefully this video. I don't have the same understanding than you. 104dB is the level they get in their test (and they seem not being very sure of the value). It is not said to be the sensitivity (this in the limit of my understanding of English!). They explain how they answer to the need of power (ie the need for people at 30m), the electrical power that will be applied to the panel (continuous, program, peak). At 1.50' you have the graph below showing a sensitivity around 90dB which is consistent with the documentation.
Christian,
I'm pretty sure it was 3M 77 Spray Adhesive.
Eric
https://www.3m.com/3M/en_US/p/dc/v000350555/
I did not see myself to developing an interest in this type of speaker, but other influences at present has made this speaker design and another speaker method quite desirable to learn more about.
Firstly Headphones use has become an attractive option to be used in place of speakers and not considered prior to this throughout my whole history of listening to music on the home system.
This Flat speaker design has now become quite an interesting concept and one I think can work well in conjunction with the Headphone idea.
The change for types of speakers being considered are two fold, which is that firstly I am in the not too distant future temporarily changing my living arrangements and will be living for a period in a Large Caravan whilst my home undergoes a repair of a structural issue.
Secondly my Wife enjoys my HiFi system and has no issues with it as long as it is confined to a dedicated space, where security is easily maintained.
Valve Amp's, are not a item to have exposed to an area where Grandchildren play hard.
This will be maintained when the home is once more lived in.
We both like the idea of having a second system in the main living area, but one that is easily concealed and one that does not create any concerns for the devices used. Hence this puts my spare Amps that could be donated out of the picture.
A Headphone Speaker fits in perfectly with this ambition, but this does not allow for usual listening methods for both Music and very basic
Home Cinema.
Conventional Speakers are not welcome by my wife, even in a furniture quality aesthetic, the term easily concealed is the brief.
This Flat Panel Speaker design under discussion and performing as a functioning speaker does in my mind meet the brief.
Firstly it functions as a Speaker, secondly it seems from my browse through a selection of posts in the thread, the aesthetic can be produced in many ways from a wall hanging art work appearance to a Photo Print on a Fascia.
I know I can make this work and produce a speaker that can be satisfactorily disguised within a room.
My wife would happily continue with Alexia for the second system, but that is where I stumble, and can't quite endear to that as the option.
More importantly I do not need a second system that is to be considered as a comparative in quality to the main system, I am looking to use modern miniaturised devices, such as Streaming or CD that can offer a performance that can be lived with as background music, the Speaker will be working with these devices and be extended in use to supply a little extra improvement on the speakers belonging to the TV when watching a Movie.
Apologies for the long winded approach, but any directions towards Construction of the Panels and Dimensions, along with the Amplification requirements to drive these speakers will be very much appreciated.
I can start a Trial early and intend on using it whilst living in the Caravan, I have access to Foam Signage Materials of approx' 1/8" (3mm) thickness up to a dimension of 2' x 18" (600mm x 450mm).
A material that has come to mind and is also available is a 1/32" (1.2mm) Roofing Membrane made from PVC and has a mesh reinforcement embedded. This is available in a Large Dimension.
Firstly Headphones use has become an attractive option to be used in place of speakers and not considered prior to this throughout my whole history of listening to music on the home system.
This Flat speaker design has now become quite an interesting concept and one I think can work well in conjunction with the Headphone idea.
The change for types of speakers being considered are two fold, which is that firstly I am in the not too distant future temporarily changing my living arrangements and will be living for a period in a Large Caravan whilst my home undergoes a repair of a structural issue.
Secondly my Wife enjoys my HiFi system and has no issues with it as long as it is confined to a dedicated space, where security is easily maintained.
Valve Amp's, are not a item to have exposed to an area where Grandchildren play hard.
This will be maintained when the home is once more lived in.
We both like the idea of having a second system in the main living area, but one that is easily concealed and one that does not create any concerns for the devices used. Hence this puts my spare Amps that could be donated out of the picture.
A Headphone Speaker fits in perfectly with this ambition, but this does not allow for usual listening methods for both Music and very basic
Home Cinema.
Conventional Speakers are not welcome by my wife, even in a furniture quality aesthetic, the term easily concealed is the brief.
This Flat Panel Speaker design under discussion and performing as a functioning speaker does in my mind meet the brief.
Firstly it functions as a Speaker, secondly it seems from my browse through a selection of posts in the thread, the aesthetic can be produced in many ways from a wall hanging art work appearance to a Photo Print on a Fascia.
I know I can make this work and produce a speaker that can be satisfactorily disguised within a room.
My wife would happily continue with Alexia for the second system, but that is where I stumble, and can't quite endear to that as the option.
More importantly I do not need a second system that is to be considered as a comparative in quality to the main system, I am looking to use modern miniaturised devices, such as Streaming or CD that can offer a performance that can be lived with as background music, the Speaker will be working with these devices and be extended in use to supply a little extra improvement on the speakers belonging to the TV when watching a Movie.
Apologies for the long winded approach, but any directions towards Construction of the Panels and Dimensions, along with the Amplification requirements to drive these speakers will be very much appreciated.
I can start a Trial early and intend on using it whilst living in the Caravan, I have access to Foam Signage Materials of approx' 1/8" (3mm) thickness up to a dimension of 2' x 18" (600mm x 450mm).
A material that has come to mind and is also available is a 1/32" (1.2mm) Roofing Membrane made from PVC and has a mesh reinforcement embedded. This is available in a Large Dimension.
JohnnoG,
Since you mentioned disguising the DMLs as works of art (paintings or photo print), why not go directly to the natural substance that is used in that field, the art canvas? You could even use actual paintings, if you don't mind affixing the wooden puck directly to its back. A melamine foam backdrop could be covered in stylish cloth to act as a rear-field diffuser, while looking like only a stylish surround of the painting. If you do not play music with heavily active deep bass at moderate to loud volumes, you could expect response down to 40-45Hz. Otherwise, a high-pass filter set at about 50-60Hz in combination with a sub could be used. That is what I am doing, to my great satisfaction. Blank canvases are quite inexpensive, too, and very pleasing-looking paintings can be found in thrift stores quite reasonably. 70-100 3x5" melamine sponges can be had from ebay for about $6-10.
Since you mentioned disguising the DMLs as works of art (paintings or photo print), why not go directly to the natural substance that is used in that field, the art canvas? You could even use actual paintings, if you don't mind affixing the wooden puck directly to its back. A melamine foam backdrop could be covered in stylish cloth to act as a rear-field diffuser, while looking like only a stylish surround of the painting. If you do not play music with heavily active deep bass at moderate to loud volumes, you could expect response down to 40-45Hz. Otherwise, a high-pass filter set at about 50-60Hz in combination with a sub could be used. That is what I am doing, to my great satisfaction. Blank canvases are quite inexpensive, too, and very pleasing-looking paintings can be found in thrift stores quite reasonably. 70-100 3x5" melamine sponges can be had from ebay for about $6-10.
Speaking of the Tectonic "educational" videos, I realized only recently that there are many more of these than I originally thought. There are actually 21 of them, by my count in the series with Tim and Marco.
https://www.youtube.com/user/TectonicAudioLabs/videos?view=0&sort=da&flow=grid
https://www.youtube.com/user/TectonicAudioLabs/videos?view=0&sort=da&flow=grid
Thank You for the reply and offering solutions that are encouraging, I can embrace these types of concepts and am very happy to work with them.
Not too long past, when the idea was presented to set up a Stacked Array of Quad ESL 57's in the main room of the house, the idea was not encouraged due to the intrusiveness of the structure.
I was offering the idea of a Tapestry to be suspended in front of the Speakers whilst not in use, and made a point of offering that the pattern that was chosen by my wife,
This was an idea that was not going to accepted and eventually I was ousted to the separate listening space used for the system today, I have no complaints win win
.
With the above in mind, I can quite happily adopt the idea adopt the method of using a Canvas, I am a keen Photographer and have many images to be selected to be used as a Canvas Print, the selection of a shortlist of photo's is a task I can offer to my wife.
I also have a sister who is quite artistic and has a Studio set up for her hobby painting, I could see if she is happy to work on a Pair of Canvas's for me, and let my wife take on the dialogue for the finished paintings content.
I do like the idea of a Sub, I have been looking into a Sub for the main system.
For this new speaker array, it works for both listening experiences to be undertaken and I know a design can be produced that will allow it to be looked at as a furniture item or easily concealed or disguised.
I have 5 x Eminence Beta 15's on standby for a Plate Amp OB Sub Woofer Design to work with the Quad Stacked Array, these can be repurposed to a design that suits the Flat Panel Array.
For the design I intend on producing initially and using in the Caravan, what is the smallest dimension I could use to have a SQ that is sought after and work with the limitation of wall space?
When back in the home, I will have quite a substantial Wall space that can be used for a standard Stereo set up, where equidistant dimensions are required, further wall space can be made available, if a Stereo Set Up is not seen as important, additionally it would be good to understand at this stage what would be the maximum dimension that can be utilised in a large area before deficiencies for the design start to occur and are noticeable in reducing the SQ.
It looks like a speaker project is in its fledgling stages and the Honeymoon Period has already kicked in.
Not too long past, when the idea was presented to set up a Stacked Array of Quad ESL 57's in the main room of the house, the idea was not encouraged due to the intrusiveness of the structure.
I was offering the idea of a Tapestry to be suspended in front of the Speakers whilst not in use, and made a point of offering that the pattern that was chosen by my wife,
This was an idea that was not going to accepted and eventually I was ousted to the separate listening space used for the system today, I have no complaints win win
.With the above in mind, I can quite happily adopt the idea adopt the method of using a Canvas, I am a keen Photographer and have many images to be selected to be used as a Canvas Print, the selection of a shortlist of photo's is a task I can offer to my wife.
I also have a sister who is quite artistic and has a Studio set up for her hobby painting, I could see if she is happy to work on a Pair of Canvas's for me, and let my wife take on the dialogue for the finished paintings content.
I do like the idea of a Sub, I have been looking into a Sub for the main system.
For this new speaker array, it works for both listening experiences to be undertaken and I know a design can be produced that will allow it to be looked at as a furniture item or easily concealed or disguised.
I have 5 x Eminence Beta 15's on standby for a Plate Amp OB Sub Woofer Design to work with the Quad Stacked Array, these can be repurposed to a design that suits the Flat Panel Array.
For the design I intend on producing initially and using in the Caravan, what is the smallest dimension I could use to have a SQ that is sought after and work with the limitation of wall space?
When back in the home, I will have quite a substantial Wall space that can be used for a standard Stereo set up, where equidistant dimensions are required, further wall space can be made available, if a Stereo Set Up is not seen as important, additionally it would be good to understand at this stage what would be the maximum dimension that can be utilised in a large area before deficiencies for the design start to occur and are noticeable in reducing the SQ.
It looks like a speaker project is in its fledgling stages and the Honeymoon Period has already kicked in.