A Study of DMLs as a Full Range Speaker

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chdsl

Account disabled at users request
Joined 2020
BurntCoil said:
Just for fun I asked the GPTChat AI https://chat.openai.com/chat about holes and wavelength and got this answer.

"
... an array of small holes in a panel can potentially absorb sound waves that are propagating through the panel, even if the wavelength of the sound waves is greater than the small hole diameter.

One way that small holes in a panel can absorb sound waves propagating through the panel is by creating a scattering effect. When sound waves encounter the holes, they can be scattered in different directions, resulting in energy being dissipated and absorbed by the panel. This can be effective at absorbing low-frequency sound waves, as the scattering effect becomes more pronounced at lower frequencies.

Another way that small holes in a panel can absorb sound waves propagating through the panel is by creating a resonant effect. When sound waves encounter the holes, they can excite resonances within the panel, resulting in energy being dissipated and absorbed by the panel. This can be effective at absorbing higher-frequency sound waves, as the resonant effect becomes more pronounced at higher frequencies.

It's important to note that the effectiveness of small holes in a panel at absorbing sound waves will depend on a variety of factors, including the size, shape, and spacing of the holes, as well as the material of the panel and the characteristics of the incident sound waves."

Which I was amazed by. It quite a cool tool and free to use.

Burnt
Click to expand...
Hole is not a thing, so cannot absorb energy. More or less the holes can disturb any sound waves coming at it and scatter it into the air. If you'd place some soft material in those holes, jutting out as cylinders, they might absorb the energy. If you'd paste some little tablets of soft material around the perimeter, on one side or both sides, there'd be certain amount of damping, I believe.
 
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BurntCoil

BurntCoil

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Joined 2016
chdsl said:
Hole is not a thing, so cannot absorb energy. More or less the holes can disturb any sound waves coming at it and scatter it into the air. If you'd place some soft material in those holes, jutting out as cylinders, they might absorb the energy. If you'd paste some little tablets of soft material around the perimeter, on one side or both sides, there'd be certain amount of damping, I believe.
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You need to read what is posted more carefully before you reply.
 
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Eucyblues99

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Joined 2021
spedge said:
Hi DMLBES.
I noticed it was you some time ago ,but you were being so nice I did not say anything.
But I can tell you are going to kick off again.
Should I not share my new ideas ?
Or shall I keep them to myself to the grave ?
Have you applied for patents yet so we can read all about them ?
Steve.
Click to expand...
OMG - What is going on - not again surely !! :eek::oops::rolleyes:o_O
Eucy
 
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Audiofrenzy

Account Closed
Joined 2022
spedge said:
Hi DMLBES.
I noticed it was you some time ago ,but you were being so nice I did not say anything.
But I can tell you are going to kick off again.
Should I not share my new ideas ?
Or shall I keep them to myself to the grave ?
Have you applied for patents yet so we can read all about them ?
Steve.
Click to expand...
I have no idea what you are talking about?

You can do what ever you want with your ideas the same with everyone else. Unless you believe in forcing others to do what you want?
 
A

Audiofrenzy

Account Closed
Joined 2022
BurntCoil said:
Just for fun I asked the GPTChat AI https://chat.openai.com/chat about holes and wavelength and got this answer.

"
... an array of small holes in a panel can potentially absorb sound waves that are propagating through the panel, even if the wavelength of the sound waves is greater than the small hole diameter.

One way that small holes in a panel can absorb sound waves propagating through the panel is by creating a scattering effect. When sound waves encounter the holes, they can be scattered in different directions, resulting in energy being dissipated and absorbed by the panel. This can be effective at absorbing low-frequency sound waves, as the scattering effect becomes more pronounced at lower frequencies.

Another way that small holes in a panel can absorb sound waves propagating through the panel is by creating a resonant effect. When sound waves encounter the holes, they can excite resonances within the panel, resulting in energy being dissipated and absorbed by the panel. This can be effective at absorbing higher-frequency sound waves, as the resonant effect becomes more pronounced at higher frequencies.

It's important to note that the effectiveness of small holes in a panel at absorbing sound waves will depend on a variety of factors, including the size, shape, and spacing of the holes, as well as the material of the panel and the characteristics of the incident sound waves."

Which I was amazed by. It quite a cool tool and free to use.

Burnt
Click to expand...
I've tried that technique the problem with that is the sound does come out of those holes and more so depending on the size of those holes as the larger the hole the more sound comes out of it, while smaller holes less sound but there is still sound. Also to much holes is not a good thing.
 
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A

Audiofrenzy

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Joined 2022
chdsl said:
Hole is not a thing, so cannot absorb energy. More or less the holes can disturb any sound waves coming at it and scatter it into the air. If you'd place some soft material in those holes, jutting out as cylinders, they might absorb the energy. If you'd paste some little tablets of soft material around the perimeter, on one side or both sides, there'd be certain amount of damping, I believe.
Click to expand...
I totally agree.
 
P

pway

Member
Joined 2021
BurntCoil said:
Just for fun I asked the GPTChat AI https://chat.openai.com/chat about holes and wavelength and got this answer.

"
... an array of small holes in a panel can potentially absorb sound waves that are propagating through the panel, even if the wavelength of the sound waves is greater than the small hole diameter.

One way that small holes in a panel can absorb sound waves propagating through the panel is by creating a scattering effect. When sound waves encounter the holes, they can be scattered in different directions, resulting in energy being dissipated and absorbed by the panel. This can be effective at absorbing low-frequency sound waves, as the scattering effect becomes more pronounced at lower frequencies.

Another way that small holes in a panel can absorb sound waves propagating through the panel is by creating a resonant effect. When sound waves encounter the holes, they can excite resonances within the panel, resulting in energy being dissipated and absorbed by the panel. This can be effective at absorbing higher-frequency sound waves, as the resonant effect becomes more pronounced at higher frequencies.

It's important to note that the effectiveness of small holes in a panel at absorbing sound waves will depend on a variety of factors, including the size, shape, and spacing of the holes, as well as the material of the panel and the characteristics of the incident sound waves."

Which I was amazed by. It quite a cool tool and free to use.

Burnt
Click to expand...
Amazing what they’re doing now with AI. Have you played with the latest image generators? Scary.

Anyhow, I am not sure how these insights can be used. If you scatter a LF wave in a small space like a panel, does it make a difference? The wave is still at the same frequency, and I think will still find the same modal energy valleys. Scattering will dissipate energy where there is a wider space for it to go (eg light scattering from a beam). Not sure how it can lead to damping in this case.

Certainly the resonance bit I can see as useful. If you can create tuneable resonance in a particular structure you can either accentuate a frequency or, with the addition of damping, you can absorb it.

My point is that there is no damping without a damping material, or a mechanism to conduct energy to a larger reservoir. Resonance or scattering might help you to improve or tune it, but there is no damping without a material which absorbs energy afaik.
 
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BurntCoil

BurntCoil

Member
Joined 2016
spedge said:
Burntcoil.
In your pictures of exciter designs you don't seem to show the slot on the panel similar to joppe.
Is there a reason for this ?
You just show ring connection or circle to the panel.
Do you think there is a problem with the slot ?
Steve.
Click to expand...
Hi Steve,

I don’t have a problem with the slot but in Option 3 it’s not required. I am aiming for a conventional panel driven by a conventional contact point but exploring a different motor design providing the impulses to that contact point

Burnt
 
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spedge

Member
Joined 2009
Burntcoil.
I probably should have posted my question on your new forum.
I had a quick look , but I have not had time so far, I have trouble following one forum.
I think the material you are going to apply the exciter to, could also be a deciding factor.
Should a thick heavy panel use the same sort of exciter as say a eps panel ?
Steve.
 
BurntCoil

BurntCoil

Member
Joined 2016
spedge said:
Burntcoil.
I probably should have posted my question on your new forum.
I had a quick look , but I have not had time so far, I have trouble following one forum.
I think the material you are going to apply the exciter to, could also be a deciding factor.
Should a thick heavy panel use the same sort of exciter as say a eps panel ?
Steve.
Click to expand...
An excellent question which speaks to Homeswinghome’s research on panel impedance which will vary greatly by material type. Customised exciters should in principle allow closer matching between exciter and different panel types but as for now I am just exploring different motor designs. Noted for future exploration.

Burnt
 
BurntCoil

BurntCoil

Member
Joined 2016
BurntCoil

BurntCoil

Member
Joined 2016
spedge said:
Burntcoil.
If you have built electrostatics, this should be a doddle.
Is just having a magnet on the back and the coil on the panel enough to power eps panels ?
Steve.
Click to expand...
In theory yes but there are two unknowns that can only be explored experimentally. The first concerns the force per unit area. The spiral could spread the force over too great an area to impart the impulse. The second concerns the clearance v electromotive force.
Steve these are great questions but better asked on the stub to keep this thread clean.

https://www.diyaudio.com/community/threads/dml-exciter-design.393544/

Burnt
 
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chdsl

Account disabled at users request
Joined 2020
If I had seen Joppe's experiment (#7,759) two years ago, I'd have never spent money on those exciters.

(The 8-year old knew what to do with the exciter, when he watched me connecting it to the amp. He turned the volume up a bit, heard music coming from it, turned the exciter upside down and placed it on the table. Music got amplified through the table. He played with it for a while and lost interest.)
 
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