The change in response after all the alterations so far.
All taken from the side angle
The first picture shows that the peak is now a smooth extended hump with a better all round response.
But in the second picture which was of the back angle , the response is only slightly better than the original response ?
The third picture gives a better view of the carnage !
Steve.
All taken from the side angle
The first picture shows that the peak is now a smooth extended hump with a better all round response.
But in the second picture which was of the back angle , the response is only slightly better than the original response ?
The third picture gives a better view of the carnage !
Steve.
Attachments
57buick.
It would be very interesting to see how a very large canvas panel performs.
Would the large areas of canvas become uncontrollable(wobble)?
Are you hoping to produce more LF from a larger panel ?
I only tested my canvas panels on the walls but found moving one edge away from the surface brought back the LF lost from the close mounting to the surface.
You have actually just made me think that ceiling mounting a pair of canvas panels can be an extra option.
Lowering one edge towards my seating area,this could even be a flexible mounting allowing adjustments?
Anyway,back to reality.
I'm thinking that there might be an optimum size for for best performance,such as in the patent I posted,it could be that less is sometimes more ?
My smaller panels approx 16x12 inches have a very strong in room response down to 40hz as shown in my plots.
And that is with a 10watt exciter.
I would also recommend a brace to support the exciter and small ply panel.
My ply panel was a 6x4inch 2mm balsa ply test panel which had a good FR down to about 600hz before attaching to the canvas,this I think is important.
What ever you do good luck and keep us posted.
Very interesting.
Steve.
Ps.
I used ordinary pva to glue the panel to the canvas, plus coating the canvas with no problems.
I'm not going to be able get that panel off of the canvas without major damage being caused.
It would be very interesting to see how a very large canvas panel performs.
Would the large areas of canvas become uncontrollable(wobble)?
Are you hoping to produce more LF from a larger panel ?
I only tested my canvas panels on the walls but found moving one edge away from the surface brought back the LF lost from the close mounting to the surface.
You have actually just made me think that ceiling mounting a pair of canvas panels can be an extra option.
Lowering one edge towards my seating area,this could even be a flexible mounting allowing adjustments?
Anyway,back to reality.
I'm thinking that there might be an optimum size for for best performance,such as in the patent I posted,it could be that less is sometimes more ?
My smaller panels approx 16x12 inches have a very strong in room response down to 40hz as shown in my plots.
And that is with a 10watt exciter.
I would also recommend a brace to support the exciter and small ply panel.
My ply panel was a 6x4inch 2mm balsa ply test panel which had a good FR down to about 600hz before attaching to the canvas,this I think is important.
What ever you do good luck and keep us posted.
Very interesting.
Steve.
Ps.
I used ordinary pva to glue the panel to the canvas, plus coating the canvas with no problems.
I'm not going to be able get that panel off of the canvas without major damage being caused.
I'm thinking about trying .0092" aluminum flashing glued to the front of a smaller 3/4" xps sheet and the exciter mounted on the front side of panel.
Maybe 16x 20 flashing over 13x17 foam and the foams bevel cut on my saw so the thickness transitions where the foam ends.
Hoping there's less damping of the highs with the aluminum and exciter in front but it's still light and efficient like just foam?
Want to make that and a plain foam panel of the same size and compare. Maybe later in the week I'm insanely busy
Maybe 16x 20 flashing over 13x17 foam and the foams bevel cut on my saw so the thickness transitions where the foam ends.
Hoping there's less damping of the highs with the aluminum and exciter in front but it's still light and efficient like just foam?
Want to make that and a plain foam panel of the same size and compare. Maybe later in the week I'm insanely busy
Hi chis.
The 6x4inch x 2mm is a 3 ply, I got a pack of ten on line very cheap.
It is very confusing trying to buy basswood on line , they all say it is basswood, but in fact it is ply!!
I just had to send back some basswood to Amazon which turned out to be ply ,I made a complaint but after looking closely at the other sellers they are all the same?
Because it has basswood in the middle of ply that does not make it basswood! !!
Try cutting a ply with a scalpel
Don't get me wrong, the12inch 2mm ply was good quality and I almost kept them to do some testing, but I was sooooo anoyed at them for wasting my time, and I was so excited at the thought of trying basswood
Sonnar.
The link you showed is also a ply.
I thought I'd be clever and try and heat up the pva on my canvas panel with a hair dryer to see if I could get the ply to peel off.
I though wow its working, only to find it was one of the ply's pealing off
I'm thinking of using some thin muslin instead of canvas (if I get round to it) and see what happens, the ply is a little bit thinner but should still work OK ?
Steve.
The 6x4inch x 2mm is a 3 ply, I got a pack of ten on line very cheap.
It is very confusing trying to buy basswood on line , they all say it is basswood, but in fact it is ply!!
I just had to send back some basswood to Amazon which turned out to be ply ,I made a complaint but after looking closely at the other sellers they are all the same?
Because it has basswood in the middle of ply that does not make it basswood! !!
Try cutting a ply with a scalpel
Don't get me wrong, the12inch 2mm ply was good quality and I almost kept them to do some testing, but I was sooooo anoyed at them for wasting my time, and I was so excited at the thought of trying basswood
Sonnar.
The link you showed is also a ply.
I thought I'd be clever and try and heat up the pva on my canvas panel with a hair dryer to see if I could get the ply to peel off.
I though wow its working, only to find it was one of the ply's pealing off
I'm thinking of using some thin muslin instead of canvas (if I get round to it) and see what happens, the ply is a little bit thinner but should still work OK ?
Steve.
Attachments
i thought id do another recording , this time of the chopped about eps on the left.
and the large dome on the 1cm thick eps on the right.
even though they are both test panels , i find the sound to be quite remarkable, very detailed and clear using only a fraction of the watts used for heavier panels.
i know that the poor recording and conversion does not do the panels justice and you probably cant hear the difference between my other panels.
but for me in my room it is night and day.
the sound just comes alive .
that will not stop me from trying to improve these and other types of panel ,but they all have there own different problems and its just a question of trying to get around them , in my case as easy and cheaply as possible .
steve.
and the large dome on the 1cm thick eps on the right.
even though they are both test panels , i find the sound to be quite remarkable, very detailed and clear using only a fraction of the watts used for heavier panels.
i know that the poor recording and conversion does not do the panels justice and you probably cant hear the difference between my other panels.
but for me in my room it is night and day.
the sound just comes alive .
that will not stop me from trying to improve these and other types of panel ,but they all have there own different problems and its just a question of trying to get around them , in my case as easy and cheaply as possible .
steve.
Chris,
This local mob sells also basswood ply in thickness of 0.6mm
Check this place for balsa sheets (from 1mm to 25mm).
This local mob sells also basswood ply in thickness of 0.6mm
Check this place for balsa sheets (from 1mm to 25mm).
I should have pointed out that the eps panels in my last recordings on the previous page had no eq and were running full range but with the TLS xo at 300hz.
I just level matched the eps panels as close as possible, which isn't easy when you have two different frequency responses.
As for the canvas panel,I suppose I should try placing an exciter on the thin veneer left on the canvas and see what the response might be before pulling it apart?
Why not
Steve.
I just level matched the eps panels as close as possible, which isn't easy when you have two different frequency responses.
As for the canvas panel,I suppose I should try placing an exciter on the thin veneer left on the canvas and see what the response might be before pulling it apart?
Why not
Steve.
re: AMPLIFICATION
Do DMLs and exciters have the same sensitivity to the quality of amplification that conventional speakers do?
What factors do DIYers need to consider in selecting amps for DMLs?
I haven't seen this discussed through the thread (although I could have missed something).
Andreas
Do DMLs and exciters have the same sensitivity to the quality of amplification that conventional speakers do?
What factors do DIYers need to consider in selecting amps for DMLs?
I haven't seen this discussed through the thread (although I could have missed something).
Andreas
I am impressed after listening to these .mp3s. I am in process of trying these with foam boards and hope for a good sound....
re amplification.
Aagas.
Amplifiers are a personal taste so can cause a lot of discussion.
My ten watt exciters are easy to drive depending on what you mount them on of course.
As long as you like the sound of your amp and it is a good match power wise to the exciter I don't see a problem.
I do like my small digital amp which works well with my exciters although I do have other amps including valve if needed.
Steve.
Aagas.
Amplifiers are a personal taste so can cause a lot of discussion.
My ten watt exciters are easy to drive depending on what you mount them on of course.
As long as you like the sound of your amp and it is a good match power wise to the exciter I don't see a problem.
I do like my small digital amp which works well with my exciters although I do have other amps including valve if needed.
Steve.
Gychang.
Glad you like the recordings, although they were originally recorded in mp3 I had to convert them to mp4 for this forum.
I presume by foam you mean xps which seems to have problems with hf .
But you've got to start somewhere I suppose?
Although I'd always recommend eps for starters. As it is cheap if 70 grade is used and has very good sound if handled right.
Although some do come close ,see next post, when I get around to it.
Steve.
Glad you like the recordings, although they were originally recorded in mp3 I had to convert them to mp4 for this forum.
I presume by foam you mean xps which seems to have problems with hf .
But you've got to start somewhere I suppose?
Although I'd always recommend eps for starters. As it is cheap if 70 grade is used and has very good sound if handled right.
Although some do come close ,see next post, when I get around to it.
Steve.
I'm just posting some pictures before I get too confused which they are?
I have taken quite a few
The first pic is of an old eps HD grade 1cm panel with a flat mesh covering the center of the exciter area.
The third pic is of the response of the panel(sorry I got them in the wrong order).
The second is the response of the canvas art panel with just the thin veneer still stuck on to the canvas, the low end below about 300 hz has dropped of somewhat.
But this is not a problem for me as I use the TLS for this area.
The hf and midrange holds up well, more to come on this when I get the time.
Steve.
I have taken quite a few
The first pic is of an old eps HD grade 1cm panel with a flat mesh covering the center of the exciter area.
The third pic is of the response of the panel(sorry I got them in the wrong order).
The second is the response of the canvas art panel with just the thin veneer still stuck on to the canvas, the low end below about 300 hz has dropped of somewhat.
But this is not a problem for me as I use the TLS for this area.
The hf and midrange holds up well, more to come on this when I get the time.
Steve.
Attachments
In the first picture I've managed to smooth out the response a little on the canvas panel without eq, this is at 12inches in front of the panel.
The second picture is the response at least 3m into the room, as you can see the room suckout has taken its toll below about 200hz ,as I say no problem for me, but it would be nice to get the low end response back that the 2mm ply gave.
But I am quite enjoying the mid and high performance so far,I spent most of the first day going through my cd collection.
The second day I just couldn't get the sound right it just sounded off ?
Today I noticed that one of the switches on my sub amp had somehow got tripped, I thought I was going mad and that what I had heard the first day must have been my imagination
I'm not sure where to go from now ? Is it the cascamite that is helping the sound ?if so I've got problems as cascamite is very brittle and cracks badly over time.
How much is the very thin veneer?
The only thing I can think of close to cascamite is maybe fibreglass which is pretty messy.
Epoxy maybe to thick?
I'll have to think about it.
I'm getting side tracked again
Steve.
The second picture is the response at least 3m into the room, as you can see the room suckout has taken its toll below about 200hz ,as I say no problem for me, but it would be nice to get the low end response back that the 2mm ply gave.
But I am quite enjoying the mid and high performance so far,I spent most of the first day going through my cd collection.
The second day I just couldn't get the sound right it just sounded off ?
Today I noticed that one of the switches on my sub amp had somehow got tripped, I thought I was going mad and that what I had heard the first day must have been my imagination
I'm not sure where to go from now ? Is it the cascamite that is helping the sound ?if so I've got problems as cascamite is very brittle and cracks badly over time.
How much is the very thin veneer?
The only thing I can think of close to cascamite is maybe fibreglass which is pretty messy.
Epoxy maybe to thick?
I'll have to think about it.
I'm getting side tracked again
Steve.
Attachments
Steve --
I've repurposed a Hypex plate amp for my DMLs and can't find any obvious fault with them.
That said, my question really goes to wondering if DMLs just don't need quality amplifiers (of whatever kind).
Coming at my amp question from a different direction, can we define an optimal amplifier to drive DMLs or perhaps (given real world engineering trade-offs) the key objective characteristics (thinks we can measure) of amplifiers that most affect their performance with DML's?
Maybe too broad a set of questions.
Maybe too much, .
Just wondering.
Andreas
I've repurposed a Hypex plate amp for my DMLs and can't find any obvious fault with them.
That said, my question really goes to wondering if DMLs just don't need quality amplifiers (of whatever kind).
Coming at my amp question from a different direction, can we define an optimal amplifier to drive DMLs or perhaps (given real world engineering trade-offs) the key objective characteristics (thinks we can measure) of amplifiers that most affect their performance with DML's?
Maybe too broad a set of questions.
Maybe too much, .
in amplifiers.
Just wondering.
Andreas