I beg to differ as usual as there are MANY WAYS of building good sounding DML panels. I have around 15 different types of DML designs. Whats funny is when people ask about my designs the first thing that pops into my head is which one?🤣Completely agreed.
I battle to see what the problem is with somebody "copying " somebody else's "design."
Anybody is free to copy and improve on anything that I post, for example. That would be an enormous compliment to me.
There are not so many different ways of building panels and then mounting them somehow. Chances are that anybody building panels will invariably use the same techniques as somebody else at some stage. But if there is really some apparently secret way of doing it then it should be patented!
Actually the chances are very low that someone will eventually use the same technique for the mere fact that most stop/quit at the beginning stages of development and or rely to much on scientific measurements. 😆
The secret technique used for building good sounding DML's is ones EARS!!!!!!!
Thats because you didnt post a video/sound clip of alu dome panels playing. If it sounds good you will get people to try it. Like I said most wont try it if they have never heard it in person and or even through a video/sound clip.AF... Unless you're selling these designs, is there any harm in having people copy them?... After all, "Imitation is the sincerest form of flattery"... I've tried my darnedest to get someone to try the alu dome and failed miserably, so I am definitely lacking in flattery.
Eucy
Possibly, but I admit have trouble accepting that listening to a recording of a panel on a set of headphones will reproduce what that panel actually sounds like, so I rarely listen to posted clips..Shrug🤷🤷♀️🤷♂️Thats because you didnt post a video/sound clip of alu dome panels playing. If it sounds good you will get people to try it. Like I said most wont try it if they have never heard it in person and or even through a video/sound clip.
I've lost all of my FR curves through a computer reset, so I'll have to do them again
And my panels may not have the same dome result as others, so I was after a wider testing audience
Anyway, back to your panels, are we ever going to see any??
Eucy
Do any of these so called scholarly articles pertain directly to DML technology?I have been reading through a lot of scholarly articles on material design for acoustic properties.
There’s a lot of good research into how to reduce or remove resonance or natural frequencies in the mechanical fields, due to its need in the fields of building design, bridge design, and large machine design where natural frequencies can cause the whole to shake apart.
And there’s good research in the material, vehicle, and building design fields for novel approaches to sound insulation.
There are two key sets of issues faced when designing a DML.
Low frequency modes cause modal shapes in the panel which are alternating between efficient then inefficient. This happens up to about 1000hz but varies between materials and board sizes.
High frequency modes are either affected by natural resonances in the material, or coincidence resonance where different frequencies amplify or attenuate each other because of having mode overlaps.
For low frequencies I was for ways to mitigate the inefficient modes.
And for high frequencies i was looking for ways to reduce the modal overlap caused by edge reflection.
Damping the edge by suspending the panel with rubber introduces a smoothing of the SPL frequency graph. However for the high frequencies it adds a attenuation slope.
In a paper I linked to in a previous post, when looking for ways to reduce low frequency resonances in a material a side affect of the study showed that the higher frequencies were amplified and the number of modal overlaps were reduced.
The addition of perforation to a board introduces smoothing to the SPL frequency graph too but it attenuates low frequencies and amplifies the high frequencies by doing a frequency shift on the modal resonances.
Resonance frequencies are affected in the majority by weight and stiffness of the panel so the perforations are changing these factors, while also diffusing the sound waves which reduces the modal overlap.
So this is why I started testing perforated panels and highly dampened panels.
My current best speaker is two panels side by side, one with a single 1mm carbon fiber 30x30cm glued to a 2mm neoprene sheet which handles 70-1500hz, and a basswood 3mm aramid honeycomb basswood sandwich with free edges and a planar spring which has a ring of 5mm holes drilled around the edge of the foot of the exciter, positioned at the recommended 2/3rds position.
The average of these two panels is producing a spl response that follows the harmon curve all the way to 18khz.
I’m currently just refining this build to figure out a good way to frame it up.
@homeswinghome
The source for the frequency demarcation for low and high frequencies.
https://www.politesi.polimi.it/bitstream/10589/89767/3/Moschini_2014.pdf;vibroacoustic
Around page 49 it discusses it.
The paper that shows a change in upper frequency that you’re asking about is
https://www.extrica.com/article/10418/pdf
If I leave the edges free I always have a higher spl in the upper frequencies compared to when I have the edges covered in rubber.
The source for the frequency demarcation for low and high frequencies.
https://www.politesi.polimi.it/bitstream/10589/89767/3/Moschini_2014.pdf;vibroacoustic
Around page 49 it discusses it.
The paper that shows a change in upper frequency that you’re asking about is
https://www.extrica.com/article/10418/pdf
Ah, I just reread what you were asking. The attenuation for high frequency on damped edge panels is just what I see in the SPL graph.Hello Jamie
Do you have source for that? sorry if already posted... I ask because at the same time, I have read the post from Eric in a sub-thread showing the good result of Poron as suspension material. The panel is damped but no slope. Have a look Effect of Boundary Conditions on the Ringing of DML Speaker Panels #178
Christian
If I leave the edges free I always have a higher spl in the upper frequencies compared to when I have the edges covered in rubber.
Looking up Poron 92, I see there are many densities available, what density did Eric use, or did I miss that reference?Hello Jamie
Do you have source for that? sorry if already posted... I ask because at the same time, I have read the post from Eric in a sub-thread showing the good result of Poron as suspension material. The panel is damped but no slope. Have a look Effect of Boundary Conditions on the Ringing of DML Speaker Panels #178
Christian
Eucy
The only true way to know what a loudspeaker sounds like is to listen to it in person. If that is not possible since most of us live far away from each other the next best thing is a recording and the better the recording the better it will sound. Heck all music we play and listen to on our audio components comes from a recording. The only way to hear actual music not from a recording is "LIVE", music.Possibly, but I admit have trouble accepting that listening to a recording of a panel on a set of headphones will reproduce what that panel actually sounds like, so I rarely listen to posted clips..Shrug🤷🤷♀️🤷♂️
I've lost all of my FR curves through a computer reset, so I'll have to do them again
And my panels may not have the same dome result as others, so I was after a wider testing audience
Anyway, back to your panels, are we ever going to see any??
Eucy
What does FR curves have to do with posting a vid?
Not asking for others results all we need is your results for others to hear and they can judge for themselves as we are the audience.
Sigh, the same way I cant convince and or force others to post a video/sound clip of there panels playing.
You can get free high density EPS from your local food store as some fruits like grapes are shipped in these EPS containers. Most times they just throw the old containers away.
Not to mention that the carpet enhances the EPS. 🤣🤣🤣
On a serious note there are indentions from the letters and smaller circles which need to be sanded down for a flat even surface. I hate sanding EPS as it gets all over you as the fine dust particles can be dangerous if inhaled as it can damage your lungs so a good mask and eye protection is required.
Not to mention that the carpet enhances the EPS. 🤣🤣🤣
On a serious note there are indentions from the letters and smaller circles which need to be sanded down for a flat even surface. I hate sanding EPS as it gets all over you as the fine dust particles can be dangerous if inhaled as it can damage your lungs so a good mask and eye protection is required.
You'll most likely disagree, but I view them as a visualisation of an objective listening test, albeit without timbre etcWhat does FR curves have to do with posting a vid?
🤷♂️. When you don't place much stock in a second hand listening test, an FR curve can be something of a guide.
Eucy
An experienced designer will derive more useful information from a decent FR/distortion/impulse/GD response curve than from a cheap cell-phone recording made in a domestic environment of even a pristine recording made in a world-class recording studio. Listen to any cell-phone recording made in a concert hall of a good live performance to prove the point that such recordings are pretty much utterly useless.
Serious designers, listeners and audiophiles will probably never utilise a microphone recording of any kind, of any system to demonstrate speaker sound. It doesn't, and it cannot. The only thing one could possibly demonstrate like that would be slap-back or the reverb tail. Nothing else.
Serious designers, listeners and audiophiles will probably never utilise a microphone recording of any kind, of any system to demonstrate speaker sound. It doesn't, and it cannot. The only thing one could possibly demonstrate like that would be slap-back or the reverb tail. Nothing else.
Sure, but I am not talking about designing I am talking about listening to ones panels since we cant hear it in person the only other way is from a recording.An experienced designer will derive more useful information from a decent FR/distortion/impulse/GD response curve than from a cheap cell-phone recording made in a domestic environment of even a pristine recording made in a world-class recording studio. Listen to any cell-phone recording made in a concert hall of a good live performance to prove the point that such recordings are pretty much utterly useless.
Serious designers, listeners and audiophiles will probably never utilise a microphone recording of any kind, of any system to demonstrate speaker sound. It doesn't, and it cannot. The only thing one could possibly demonstrate like that would be slap-back or the reverb tail. Nothing else.
There have been many serious designers, listeners and audiophiles that have utilized recordings to demonstrate speaker sound its just facts. This is how I know you are not an audiophile, designer, or a serious listener but just a PA listener. 🤣 🤣 🤣
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Even for PA application that sounds horrible. 🤣🤣🤣Oh! Oh! ... Here's a fantastic cell-phone recording of my most recent panels. The clarity, detail and imaging are totally indescribable if you can ignore the room sound.
🤣
Recording is not another way to listening to speakers, especially not a cell phone recording.Sure, but I am not talking about designing I am talking about listening to ones panels since we cant hear it in person the only other way is from a recording.
There have been many serious designers, listeners and audiophiles that have utilized recordings to demonstrate speaker sound its just facts. This is how I know you are not an audiophile, designer, or a serious listener but just a PA listener. 🤣 🤣 🤣
I'm sure you can find some audiophiles that think that they can convey the quality of their systems via youtube, but at the same time argues about how mp3 completely destroys music and are telling themselves they are able to hear the difference when using a grossly overpriced mains cable for their amp.
I really doubt that anyone I know involved in with audio on at least a semi-professional level could contain their laughter if I wanted to demonstrate how good my speakers sounds from a phone recording, and I would lose any ounce of credibility I might have by even suggesting it as being worthwhile. They are interested in either measurements or actually listening to them in person.
Except for a live band playing the only other way to listen to music is from a recording, unless you know of another method that I dont know about?🤣🤣🤣Recording is not another way to listening to speakers, especially not a cell phone recording.
I'm sure you can find some audiophiles that think that they can convey the quality of their systems via youtube, but at the same time argues about how mp3 completely destroys music and are telling themselves they are able to hear the difference when using a grossly overpriced mains cable for their amp.
I really doubt that anyone I know involved in with audio on at least a semi-professional level could contain their laughter if I wanted to demonstrate how good my speakers sounds from a phone recording, and I would lose any ounce of credibility I might have by even suggesting it as being worthwhile. They are interested in either measurements or actually listening to them in person.
and of course the better the recording the better the sound quality....Some audiophiles purchase 10k and above microphones/recorders in which if you were to compare it to the original track it would only have very slight differences as the quality is that good.
Again many serious designers, audiophiles and listeners have done it as its the only other way to hear music without being there in person also without having lost any credibility.
XRK has DONE IT!!!!!! Are you laughing at him Leob? 🙄 I doubt he has lost any credibility. 😉
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The IRONIC part is most of yawl ASKING for my designs think I am WRONG. So WHY are some of you so desperate to see my designs? I must be doing something RIGHT. 🤣 🤣 🤣
This is brilliant.Recording is not another way to listening to speakers, especially not a cell phone recording.
I'm sure you can find some audiophiles that think that they can convey the quality of their systems via youtube, but at the same time argues about how mp3 completely destroys music and are telling themselves they are able to hear the difference when using a grossly overpriced mains cable for their amp.
I really doubt that anyone I know involved in with audio on at least a semi-professional level could contain their laughter if I wanted to demonstrate how good my speakers sounds from a phone recording, and I would lose any ounce of credibility I might have by even suggesting it as being worthwhile. They are interested in either measurements or actually listening to them in person.
The posts on here fascinate me at times. Sometimes they reveal what a posters game really is. Especially if into carpets.This is brilliant.
Anyway. I made a recording using a mobile phone of a commercial dml. Rather cheap when they were sold and liked by people who bought them. I have heard other commercial units in the past. What's changed is i can now measure performance pretty easily.
Mobile ~2m away. Panels 120mm tall. Posted it to someone who clued me up on using a mobile for this sort of use. I just used what was in the phone. Had a nose at app's and thought Dolby's would be the best answer but don't do some of the thing it can do. However I have a measuring mic and the the kit to use it so will use that in the future and post sound files. No interest in recording stereo. If mono is fine from a speaker that will look after itself other than radiation pattern differences.
🤣🤣🤣 I have no idea where the clicks come from
Remember 120mm tall. The frequency response is extended via a rather simple volume control on the woofer. It needs a tiny touch of that to get all of her voices lower register.
So I'm interested in 2 way. There is a youtuber that goes all of the way through constructing some fairly large ones. He even demo's them and most of the music he plays is similar to what it posted on here. Then come a famous female pop singer. My feelings - a rather crap mix. Maybe he recorded it and those can crop up even live. How did he have his tone or whatever controls set? Or is it the speakers.
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