Thank you Eric. Yes, we all would like small panels that go lower than 100Hz. I just wanted an indication of the size limits of the plywoods. Using a high aspect ratio (3:1 or 4:1) with a 12” wide panel brings me back to the size of the Tall Blondes.
I really appreciate your experiments, measurements, findings, and contributions on this thread.
In some ways that is correct. There are basically two types of effects, those that introduce delays, and those that directly modify the waveform.IT ONLY JUST OCCURED TO ME >
There many, many numerous reports of how DML's sound great but don't necessarily measure well.
The fast attack but slower decay is exactly analogous to Reverb, and a fundamental property of the panel/plate.
In recording, short time reverb is used to enhance sounds, and also create a 'space'.
This can explain how DML's may not be technically accurate, yet sound truly great !
The following info. of "Plate Reverb" is surely something to think about
https://www.vintagedigital.com.au/emt-140-plate-reverb/
In the first group you have delay effects obviously, but also reverb, chorus, phaser and flanger. Also EQ in a sense, which is a frequency specific delay.
In the second group you have compressor, expander, distortion, saturation and waveshaping.
Since the plate will emit the same frequency from multiple points you will hear multiple versions of the same signal with a slight delay, which is in essence what most delay based effects will be doing, just with different number of copies with different timing.
I would say a good plate have more of a chorus effect, which is a few copies of the signals with slightly different delay. Reverb is a burst with lots of delays.
I don't think slapping an effect on your master is a good idea though. That should be done during production or mastering if it benefits a track.
But of course DML is not an effect you can add to the signal. Adding a reverb to the mix will not be a substitute. DML is an effect that has to be created in physical space, and works in a way that our hearing and even shape of our ears are constructed to handle.
Perhaps using some psychoacoustic modelling listened to on headphones could recreate the sound of DML, but in general, unlike your regular chorus or reverb, DML effect can result in a sound that no producer or mastering engineer can achieve.
@Leob
Yes, I am aware of the full gamut of Studio FX and understand their differences >
I was trying to keep things short & simple.
My main point was that compared to the electrical input signal, the sonic output of a DML
IS adding an effect (of sorts) to the signal. The pure physics of it can't be denied.
Yes, I am aware of the full gamut of Studio FX and understand their differences >
I was trying to keep things short & simple.
My main point was that compared to the electrical input signal, the sonic output of a DML
IS adding an effect (of sorts) to the signal. The pure physics of it can't be denied.
Eric.
Can you describe to me , a way of physically damping those resonances in your spectrogram, in a way that does not affect all of the other frequencies on the panel?
I personally prefer as little damping as possible but sometimes it is necessary on certain materials.
I usually use a few weights or mounting points, shapes, to sort out these problems, or throw them in the bin, if they are that bad.
A good panel material should have a clean clear sound with no discernable ringing.
Did you read the white papers by Mapp and Azima ?
Were they of any help to you?
Steve.
As can be seen in the first picture on the left, I used an angled length of wood to help break up the standing wave on this ply panel.
The second picture shows how I reduced the standing wave on a long narrow panel.
I have posted pictures somewhere on this forum of this panel.
It showed the panel clamped at the bottom, but with an angled brace clamped in a sturdy vice.
You could also cut or brace the top, or both .
I felt that clamping the bottom of the tall thin panel gave a good sound and a sturdy base for supporting the panel.
So solved two problems for the price of one👍
Steve.
The second picture shows how I reduced the standing wave on a long narrow panel.
I have posted pictures somewhere on this forum of this panel.
It showed the panel clamped at the bottom, but with an angled brace clamped in a sturdy vice.
You could also cut or brace the top, or both .
I felt that clamping the bottom of the tall thin panel gave a good sound and a sturdy base for supporting the panel.
So solved two problems for the price of one👍
Steve.
Attachments
Hello Bruce.
EPS,( NOT XPS) has been my favourite for many many years .
But it needs a lot of delicate care and attention to get it sounding its best.
The same can be said for the other panels, as far as I am concerned, they are all good sounding panels and will not disappoint.
Especially as they are usually cheap or free.
There is only one, that I know of , that sounds good straight from the get go, all you have to do is slap an exciter on it.
There is possibly a way to improve this panel ,I believe.
This sample was sent to me by JohnnoG, but it is very expensive and probably hard to get hold of.
I will have to pm John to see how he is getting on, but I know he is very busy.
It probably depends on how you intend to use them in your environment ?
Steve.
Steve - My environment is 14’ x 18’ x 8’ carpeted, acoustical tile ceiling. I want all genres of music to sound right, but the most challenging source example is Sheffield’s Drum and Track Record, Jim Keltner at live levels. I want listening to that to put a smile on my friend’s face! I have high density EPS and a wire cutter to make any thickness. I am not limited by panel size. Will your preferred 10-watt exciter be enough? I have an electronic crossover/equalizer, infinite baffle sub and lots of power. I need dimensions, PVA or epoxy, suspension method, etc. I’ve read and valued so much of your expertise, here and at AC, but I still don’t know what you’d specifically recommend for my needs. Thanks, Bruce.
Not an audio 'clip', but still general info. >
EPS vs XPS
https://www.google.com/search?q=wha...ate=ive&vld=cid:87a33537,vid:sX-vym8qMbg,st:0
EPS vs XPS
https://www.google.com/search?q=wha...ate=ive&vld=cid:87a33537,vid:sX-vym8qMbg,st:0
Due to my lack of talent for working with double-sided tape, here's my 14" birch with frame.
I ripped 1/4" strips of XPS, which I have plenty of, and glued to the inside of each one of those long boards, and then sandwich the edges of the plywood between the xps, tightening with bolts. I need to get more bolts, there's enough to do the basic job, but, it's a delicate balance to constrain the board enough not to buzz but without killing its relatively epic bass (for dml). The board might look straight but definitely isn't when trying to sandwich it, and so I think at least 4 bolts on each side, and then gradually tighten -- however, might not matter much because at the end of the day, crossing over at the trusty 100hz and letting the sub do its thing may sound the best anyway.
I did a long left-channel comparison with one my xps panels connected in series to my dml tweeter, both powered by the same version of amp and can easily toggle either off and on. More impressive than the bass is the highs, the articulation is off the charts; it might be too much. It also has more depth than my xps. The bad -- cold and bright. Lacking in mids. If I had to do a final build tonight, Id rip 10" off one xps panel and mount it to the front of the birch. Together they sound very good.
Coming from PE in a few days is a test mic. Today my -fhe-4 exciters came. So tomorrow I can try with the same exciter Eric uses. If I can figure out REW, I guess I can see exactly what frequencies are missing and go from there.
I ripped 1/4" strips of XPS, which I have plenty of, and glued to the inside of each one of those long boards, and then sandwich the edges of the plywood between the xps, tightening with bolts. I need to get more bolts, there's enough to do the basic job, but, it's a delicate balance to constrain the board enough not to buzz but without killing its relatively epic bass (for dml). The board might look straight but definitely isn't when trying to sandwich it, and so I think at least 4 bolts on each side, and then gradually tighten -- however, might not matter much because at the end of the day, crossing over at the trusty 100hz and letting the sub do its thing may sound the best anyway.
I did a long left-channel comparison with one my xps panels connected in series to my dml tweeter, both powered by the same version of amp and can easily toggle either off and on. More impressive than the bass is the highs, the articulation is off the charts; it might be too much. It also has more depth than my xps. The bad -- cold and bright. Lacking in mids. If I had to do a final build tonight, Id rip 10" off one xps panel and mount it to the front of the birch. Together they sound very good.
Coming from PE in a few days is a test mic. Today my -fhe-4 exciters came. So tomorrow I can try with the same exciter Eric uses. If I can figure out REW, I guess I can see exactly what frequencies are missing and go from there.
Mister audio.
https://www.amazon.co.uk/Foam-Underlay-9-79m2-Laminate-Flooring/dp/B08RF3359N
From your post.
This is the only xps I have tried, in the end I applied epoxy to this panel for far better hf.
Steve.
https://www.amazon.co.uk/Foam-Underlay-9-79m2-Laminate-Flooring/dp/B08RF3359N
From your post.
This is the only xps I have tried, in the end I applied epoxy to this panel for far better hf.
Steve.
bdjohns.
Thanks ,it's nice to know that someone is interested in my designs 😀
I usually only use the lower grades of eps , but ziggy loved his large HD eps panels.
Although I did manage to get some samples of 40cm square panels .
The HD should have a better hf to 20k.
Do you have a block of eps , if so what size?
EPS would be very good for drum reproduction, it's like having the drum kit in your room.
Maybe pm me for discussions.
These exciters seem similar and are a good price at the moment.
They are 25watt exciters.
Now you have made me buy 4 of them 🙄😅
https://www.soundimports.eu/en/dayton-audio-daex25fhe-4.html
Steve.
Thanks ,it's nice to know that someone is interested in my designs 😀
I usually only use the lower grades of eps , but ziggy loved his large HD eps panels.
Although I did manage to get some samples of 40cm square panels .
The HD should have a better hf to 20k.
Do you have a block of eps , if so what size?
EPS would be very good for drum reproduction, it's like having the drum kit in your room.
Maybe pm me for discussions.
These exciters seem similar and are a good price at the moment.
They are 25watt exciters.
Now you have made me buy 4 of them 🙄😅
https://www.soundimports.eu/en/dayton-audio-daex25fhe-4.html
Steve.
Jmproject.
This looks very similar to this old patent.
He uses this method to vary the damping applied to the panel.
Cohen, was way ahead of his time.
If we had paid more attention to his design instead of cones, where would we be now ?
https://patents.google.com/patent/U...=priority:19610101&oq=inventor:+A+Cohen++1961
1961 👍
Steve.
Thanks for the historical note, Spedge. I hope his worked better than mine. Actually, it's good for the job of getting the bass just right, but not sure beyond that. But, I await a mic and we'll see if I can figure out how to do a test.
my boatload of fhe-4's came in. On the panel in the recent pic, I put one of those on in place of the thruster and then later wired it and the thruster in series, and the sum total of those experiments is that it all sounds about the same to me.
Because I just have that one birch panel and the others are somewhat torn apart, I wanted to get some stereo going. So, I took the 10" x 48" piece of birch left over from cutting the main panel, inserted it sideways and about 1" deep into the frame of the panel in that last pic and tightened the bolds lightly. Then put a fhe-4 near either end. Unbelievable how good even that sounds with the right sub mix and a little help from a couple small junker xps panels. There is a use case here -- I need a light, long, thin panel that I can put up behind my recliner in the shop here for rear surrounds on occasion, since I found a place for the Denon here rather than haul it back to the house after the testing over the holidays.
Just the single 10" x 48" piece of birch though with 2 exciters sounds better than the rears I paid $110 a piece for in the 2000s and its portable.
my boatload of fhe-4's came in. On the panel in the recent pic, I put one of those on in place of the thruster and then later wired it and the thruster in series, and the sum total of those experiments is that it all sounds about the same to me.
Because I just have that one birch panel and the others are somewhat torn apart, I wanted to get some stereo going. So, I took the 10" x 48" piece of birch left over from cutting the main panel, inserted it sideways and about 1" deep into the frame of the panel in that last pic and tightened the bolds lightly. Then put a fhe-4 near either end. Unbelievable how good even that sounds with the right sub mix and a little help from a couple small junker xps panels. There is a use case here -- I need a light, long, thin panel that I can put up behind my recliner in the shop here for rear surrounds on occasion, since I found a place for the Denon here rather than haul it back to the house after the testing over the holidays.
Just the single 10" x 48" piece of birch though with 2 exciters sounds better than the rears I paid $110 a piece for in the 2000s and its portable.
Jmproject.
I can't say I am a fan of tall thin panels, but maybe you should try my idea of only clamping the panel in a vice at the bottom , leaving the rest of the panel to vibrate.
I would recommend a couple of sturdy pieces of wood to clamp in the vice each side of the bottom of the panel.
I recently showed a picture of a tall panel with the bracing at an angle in red.
The angle will remove most of the standing waves bouncing up and down the panel, dispersing them.
I would probably not use foam damping in the clamping, to increase the reflections, not reduce them.
Although it would be easy to compare the two, or to use as variable clamping pressure, as in the patent?
Steve.
I can't say I am a fan of tall thin panels, but maybe you should try my idea of only clamping the panel in a vice at the bottom , leaving the rest of the panel to vibrate.
I would recommend a couple of sturdy pieces of wood to clamp in the vice each side of the bottom of the panel.
I recently showed a picture of a tall panel with the bracing at an angle in red.
The angle will remove most of the standing waves bouncing up and down the panel, dispersing them.
I would probably not use foam damping in the clamping, to increase the reflections, not reduce them.
Although it would be easy to compare the two, or to use as variable clamping pressure, as in the patent?
Steve.
Hi Steve
I've been revisiting some 12mm thick high density EPS panel material and although I'll persist for a while, I find it has a large amount of harsh self noise at reasonable listening levels... almost like vibrations within the depth of the panel... Have you found this with your lower density panels, and if so, how did you treat it?
At this stage I haven't coated it, but have put masking tape in a few spots, mainly directly over the exciter position to see if it tones it down... Marginally is all I'd say
Eucy