🙂🙂
We had just won all blacks at their homeland for first time in history! I liked to see rugby on the stadium a lot as a child. Then sort of lost its charm because of the social context rugby happens in here. I've always been more prone to sinners than saints... This time i'll be on the 🦌🦌🦌 side!
Huge fan of early nick cave in here! learnt to like its more "religious" stuff with Warren over the years hehe.
Didn't know of such effect. I know some people use Masking Sounds to sleep. You may have to experiment a little until you mask your particular inner noise. Wind, Sea, something relaxing, tweaked to achieve the spectrum that suits you most are good candidates.
We had just won all blacks at their homeland for first time in history! I liked to see rugby on the stadium a lot as a child. Then sort of lost its charm because of the social context rugby happens in here. I've always been more prone to sinners than saints... This time i'll be on the 🦌🦌🦌 side!
Huge fan of early nick cave in here! learnt to like its more "religious" stuff with Warren over the years hehe.
Didn't know of such effect. I know some people use Masking Sounds to sleep. You may have to experiment a little until you mask your particular inner noise. Wind, Sea, something relaxing, tweaked to achieve the spectrum that suits you most are good candidates.
Los Pumas beat the All Blacks!!??
I didn't see that! 😭😭😭
The next game wasn't so rosy for the Pumas, but kudos to them.
And I hope we 'Wallaby' them on the 31st !!🤭🤣
And 'Go the Boks'!!
And I hope we 'Wallaby' them on the 31st !!🤭🤣
And 'Go the Boks'!!
Hi Andre,
And whoever else has experimented with canvas suspension. Just wondering if you remove most of the face canvas to expose the panel (ply, Eps etc) or do you leave the canvas intact. I'm just thinking it is a pretty heavy coating for the panel compared to 1/2 strength PVA or similar and would it lower the sensitivity significantly or damp high frequency too much? Or is this not the case?
And whoever else has experimented with canvas suspension. Just wondering if you remove most of the face canvas to expose the panel (ply, Eps etc) or do you leave the canvas intact. I'm just thinking it is a pretty heavy coating for the panel compared to 1/2 strength PVA or similar and would it lower the sensitivity significantly or damp high frequency too much? Or is this not the case?
On my ply canvas panel I eventually removed the canvas from the ply surface, this does give some more detail to the sound similar to the ply only panel.
For even better results I use thin film to cover the surface, making sure to leave a couple of mm between surface and film.
As in picture.
Steve.
For even better results I use thin film to cover the surface, making sure to leave a couple of mm between surface and film.
As in picture.
Steve.
Attachments
Hi Joska,
I use artist canvas, stretched tight in its frame. And then I stretch it even tighter before gluing the insert onto the back. The insert consists of various materials depending what kinds of sound you want.
The stretched canvas in its frame increases bass performance, but makes little difference to top end or efficiency.
Here's a photo of the panel itself. This panel is 30 x 40cm, outside dimensions. Yes, it's a bit battle-worn from all the mods I've tried... 😬 You can see the foam damping strips are coming off the top and bottom edges.
The insert is Nidaplast. Inside the larger circle drawn there, are multiple little holes punched through to the front face, and which are all filled with resin.
Here's the FR. 1/6th smoothing.
This panel sounds REALLY nice with a decent, punchy bass that out-plays my larger panels.
Andre! Really great FR you have here! I tried using cotton canvas but while low frequency output gets better i get less high frequency, so I have bought some acoustic fabric (the one you use to cover cone speakers) that should help me preserve treble frequency. I know you are far away from me but where did you buy the nidaplast? in europe it seems impossible to find.
60 Hz seems to be the crash level for most/all of these panels so getting a good level at 60Hz is commendable 👍...Here's the FR. 1/6th smoothing.
This panel sounds REALLY nice with a decent, punchy bass that out-plays my larger panels.
The extra half octave down is immensely hard to reach ... I'm still trying 😁
Eucy.
My canvas ply panels crash level is 40hz.
If you tighten the canvas this will raise the lower frequency limit.
Similar to tightening the skin on a drum.
With ply canvas panels or any other hard panel atached, ,tightening the suround also restricts the movement of the panel in the low frequencies.
Steve.
My canvas ply panels crash level is 40hz.
If you tighten the canvas this will raise the lower frequency limit.
Similar to tightening the skin on a drum.
With ply canvas panels or any other hard panel atached, ,tightening the suround also restricts the movement of the panel in the low frequencies.
Steve.
I'm sure Nidaplast is not the only way to tackle the bandwidth issue.
To break it down:
To break it down:
- The bass end relies on a certain stiffness of the membrane, keeping in mind that only one surface is hardened, i.e. the one between the canvas and the NP insert.
- The stiffness of the surround, and the combined weight of the canvas, adhesive and insert will determine the resonant frequency of the assembly.
The stiffness of the surround is determined by the tension in the canvas in its frame, and also by the gap between the frame and the insert. Messing around with these two factors, and with the weight/stiffness of the canvas/insert assembly, should give you whatever roll-off you want, within reason of course. - The driver has its own Fres, which is then modified by the panel's Fres, and which results in a system Fs.
- The HF performance is determined by the mass, hardness and thickness of whatever material is between the driver and the front of the panel. A soft, thick, heavy panel will probably have worse HF performance than a thin, hard, light-weight panel. This is why I like honey-combed structures: most of the panel consists of air, and that which doesn't (the honeycomb cells) is usually quite hard.
- Midrange is determined, mostly, by whatever modes are activated by the driver(s), and also by panel mass. A heavier panel will deliver a flatter (less efficient) midrange than a very light-weight panel. Light-weight panels usually (almost always!) deliver a high-efficiency, searing midrange that I find unusable.
Hello Andre,
I understand that your canvas panel will be a bit quieter than a very lightweight one. Could you please give an approximation how much this loss is? Do you think a canvas panel would also be suitable for use in live amplification? Or only for hifi/home/studio use?
Greetings, Hans
I understand that your canvas panel will be a bit quieter than a very lightweight one. Could you please give an approximation how much this loss is? Do you think a canvas panel would also be suitable for use in live amplification? Or only for hifi/home/studio use?
Greetings, Hans
Hi Hvdz,
I used those small panels, the 30 x 40cm ones, on gigs over the weekend. I loaded two panels with four XT32-8's each, wired for 8-ohms per panel. Driven with 200Wrms x 2, and with a sub-woofer, they were sufficient for a quiet indoor gig for about 50 people, and sounded really very nice.
The next day I tried them outdoors for about 100 people... No good! The sound was bassy and indistinct, and I really battled all the way through the first set to get a good mix. I eventually gave up and connected my usual speaker cabs again. I think the problem was that the panels do not extend low enough in frequency at very high power. Of course that makes sense... it's basically an open baffle trying to run 10mm excursions at 100Hz trying to produce decent SPLs. Even two 12" drivers will not do that in open baffle configuration. So the sub-woofer was trying to do the work of the panel, and failing at it. I think there was a phase alignment problem too, but that only holds if the panel is working in pistonic mode at low-ish frequencies.
I have work-shop tested the setup on larger canvases, one size up, 40 x 50cm. One such panel is more than the surface area of two 15" drivers. Using the same XT32-8 drivers, I tested two panels wired in parallel (= 4-ohm load) at just over 700Wrms (53Vrms, 150Vp-p on the 'scope) before clipping the amp. I was running 1kHz burst signals, and the setup delivered peak 121dB SPL @ 1m. This translates down to 92.5 db/W @ 1m.
And that's not bad! I'm happy with 92db/W for PA speakers. But I have to do something about power delivery on the bass end where the panel hands over to the sub.
I'll probably end up doing the same as @Leob did with multiple panels running per sub for outdoor gigs.
Edit: The 30 x 40cm panels will deliver the same SPL at 1kHz as the larger 40 x 50cm panels. The difference is in the excursion limits at lower frequencies, where the smaller panel will battle much more than the larger panel, to produce decent levels.
For hi-fi use the panel should be okay with a single 40W driver. But it won't go very loud (for me) before the bass end starts complaining about excursion. Even so, the neighbours do complain that it's too loud, and that's good enough for me.
For studio work I'd align it carefully with a sub.
4 drivers each on a small panel... Phew!
Andre..I presume you mean 1mm excursion??, unless the canvas is really flapping, as the drivers can only manage about 1.5mm
Andre..I presume you mean 1mm excursion??, unless the canvas is really flapping, as the drivers can only manage about 1.5mm
With that panel setup, I'm pretty sure it'd be a mix of pistonic and bending which is certainly not a bad thing if it can be controlled.
Yes, the canvas was REALLY flapping...
Off the top of my head I guessed 10mm pk-pk. I checked quickly, and the actual excursion for two 12" drivers producing 120dB at 100Hz is 7.6mm pk-pk.
The XT32's have a linear Xmax of 3.2mm pk-pk, and a mechanical limit of 7mm pk-pk. But the calculated figure of 120dB at 100Hz is for a driver in an infinite baffle, and an open baffle has no hope of producing 120db at 100Hz with only 7mm or so of excursion.
So, I'll try the performance of the larger 40 x 50cm panel, which has more surface area than two 15" drivers, and the required pk-pk excursion for the above is only 4.8mm. I'm targeting a high-pass roll-off around 150Hz or so, so the excursions should not be unattainable even in an open baffle..
But having said that....
Exactly!
The panels are not pistons, and I have to allow for the panel to be bending at those frequencies. The first bending mode will give me a notch at whatever frequency the panel switches over to the 1,2 mode, so I'll have to adjust the panel stiffness in order to put that mode where I want it to interface to the sub-woofer, and the natural resonant frequency of the panel has to be adjusted by playing with its weight and surround compliance.