I've only painted small ply panels ,to help control bad panel resonances.
Didn't notice much drop in spl,
The main problem would be panel bending out of shape with larger thinner panels,but then 3mm ply tends to warp even without a coating.
Personally I'm not too keen on hard coatings, you could end up with a hard brittle sound?
Hope what ever you decide goes well for you.
Steve
Didn't notice much drop in spl,
The main problem would be panel bending out of shape with larger thinner panels,but then 3mm ply tends to warp even without a coating.
Personally I'm not too keen on hard coatings, you could end up with a hard brittle sound?
Hope what ever you decide goes well for you.
Steve
thought i would re record the chasing the dragon cd track ,soprano,using the silent internal mics on the phone.
there is still a lot of noise but it is from the recording in the church and not anything i have done.
the panels are my small love hearts 2mm card.
about 12 seconds in you can hear a door shutting,this resonance would be louder if the mics frequency didnt roll off sharply below 50 hz or so.
steve
there is still a lot of noise but it is from the recording in the church and not anything i have done.
the panels are my small love hearts 2mm card.
about 12 seconds in you can hear a door shutting,this resonance would be louder if the mics frequency didnt roll off sharply below 50 hz or so.
steve
I painted my panels with my wall paint, diluted half n half in water in order to lay it on as thin/even as possible. I had to give it 3 coats in order to cover it, and the warping was significant. I let it dry for 2 days after, laying them flat, and the warp went completely away. It didnt significantly impact the spl or sound in my opinion, but i didn't measure the difference as painting them was necessary.
Thomson.
What is the size and thickness of your panels.
Are they free floating or clamped in some way.
Did you notice if there was any reduction in the panels self noise.
Sorry for all the questions.
Steve
What is the size and thickness of your panels.
Are they free floating or clamped in some way.
Did you notice if there was any reduction in the panels self noise.
Sorry for all the questions.
Steve
They are 2x3' 5mm birch ply on a foam frame, i didnt hear anything significantly different from before painting, how would you describe self noise?
Self noise is the natural sound of the material used,metal,glass,wood,eps,if you tap them with your knuckles ,finger nails,or a stick,you will hear it's natural sound which resonates through the whole panel,when playing music,it is always there in the background a signature as you might say.
Mounting the panel on foam will have helped reduce the natural resonance sound already.
These resonances are at different frequencies on different materials and can be very irritating sometimes .
Steve
Mounting the panel on foam will have helped reduce the natural resonance sound already.
These resonances are at different frequencies on different materials and can be very irritating sometimes .
Steve
Gotcha, i'd say that there is a little bit of that dry wooden texture to the sound which was there as well before painting, its something i can live with. I suspect an even thinner board could reduce this.
You can still hear the woody sound with my 3mm rigidly clamped panels when compared to my other panels,but when playing the 3mm panels on their own the sound is not so noticeable especially if you are not too up close to the panels.
When up very close to a large 6X2 foot ply panel you are listening to large area of surface noise (self noise)so the further away the better.
This is one of the reasons I have said further back on this thread that small panels are better for small rooms and larger panels are better for large rooms
Steve
When up very close to a large 6X2 foot ply panel you are listening to large area of surface noise (self noise)so the further away the better.
This is one of the reasons I have said further back on this thread that small panels are better for small rooms and larger panels are better for large rooms
Steve
Davelang.
I was referring to the larger surface area that radiates the sound,I would class this sound as a colouration of the music.
You as a guitar designer might call this the tone of the wood, and would actively seek out a certain tone.
I point this out only to differentiate between a speaker and an instrument.
Steve
I was referring to the larger surface area that radiates the sound,I would class this sound as a colouration of the music.
You as a guitar designer might call this the tone of the wood, and would actively seek out a certain tone.
I point this out only to differentiate between a speaker and an instrument.
Steve
Now I get it. Definitely, different woods sound different. All can make good speakers/guitars but they do sound different
After reading through this thread, think I’m finally ready to start doing tests of my own. Will be clicking the order button on most of these supplies in the coming week. Any changes/suggestions welcomed.
Plan is to initially purchase 10 exciters so each material sample can be tested side by side, using the supplied adhesive tape. All to be hung on fishing line (with the exception of bottom clamped ply). Possibility for other damping/mounting arrangement left as future exercise. Exciter placement as per spedge’s? technique of moving around exciter to find sweetspot.
Exciters
These seem to be well regarded in previous posts and have one of the flattest frequency responses according to Dayton exciter datasheets.
Dayton Audio DAEX30HESF-4
Dayton Audio DAEX30HESF-4 High Efficiency Steered Flux Exciter with Shielding 30mm 40W 4 Ohm
Materials
Probably a good idea to build some acoustic panels to improve room acoustic where DMLs are to be measured and used.
https://roofinsulations.co.za/product/50mm-ecose-energy-batt-price-64kg-density/
Measurement Equipment
Amplifier
Plan on buying some cheap TPA3116D2 based amplifier boards. If this hobby becomes long term – hopefully upgrade to one of xrk971’s TPA3255 based designs (or similar).
https://www.robotics.org.za/XH-M542
Microphone
MiniDSP UMIK-1
https://www.parts-express.com/minidsp-umik-1-omni-directional-usb-measurement-calibrated-microphone--230-332
DSP
MIniDSP 2x4 HD
https://www.parts-express.com/minidsp-2x4-hd-usb-dac-digital-signal-processor--230-324
Measurement setup
I’m guessing it would be very beneficial to do these measurements outdoors to avoid room modes interfering. Will need to see if the wind and my neighbours can cooperate 😛
Plan is to initially purchase 10 exciters so each material sample can be tested side by side, using the supplied adhesive tape. All to be hung on fishing line (with the exception of bottom clamped ply). Possibility for other damping/mounting arrangement left as future exercise. Exciter placement as per spedge’s? technique of moving around exciter to find sweetspot.
Exciters
These seem to be well regarded in previous posts and have one of the flattest frequency responses according to Dayton exciter datasheets.
Dayton Audio DAEX30HESF-4
Dayton Audio DAEX30HESF-4 High Efficiency Steered Flux Exciter with Shielding 30mm 40W 4 Ohm
Materials
XPS insulation panel
Dimensions: 1500x600mm.
Ceiling Board 25x 600mm 3000mm Isoboard
EPS insulation panel
All options to be sanded and painted with 50/50 wood glue, water solution.
Plywood
Ideally want to go as large as possible (2440x610mm) whilst maintaining the 4:1 aspect ratio as identified by Veleric in #1395. Clamping from the bottom using natural rubber to dampen (old motorcycle inner tubes) as per Burntcoil’s design in #1797. If this is too floppy - side support/damping as per Burntcoil’s post #1046.
Interested to see what effect painting with boiled linseed oil would have on the plywood. Expect it would increase the surface hardness?
High potential WAF as these can be printed on.
Available in: 100x750x3mm (0.21mm thick Alluminium)
https://www.maizeyonline.co.za/rigid-substrates-sheets/i-bond-signage/i-bond-brush-silv-3-primer-3mm-0-21-indoor-coalbspr31000750i--3%3dos
Honeycomb cardboard
As with the plywood, curious what effect painting with boiled linseed oil would have.
Available in: 1000x1200x(20/30/50/90)mm
Think I’ll go for the 20mm. Use sized as is.
https://ubusi.co.za/ubusi-panels/
PLA 3D print
Got filament, will print. Is there anything in the literature suggesting that the front face of the DML should be flat? Thinking of printing an irregular shape.
Canvas picture frame
Got some lying around. Will build ala OffGridKindaGuy’s design recommendation in #913.
Acoustic PanelsDimensions: 1500x600mm.
Ceiling Board 25x 600mm 3000mm Isoboard
EPS insulation panel
All options to be sanded and painted with 50/50 wood glue, water solution.
Option 1
Dimensions: 1220x610mm.
Isowall Under Surface Bed Insulation (2440 x 1220 x 35mm) | Polystyrene | Boards & Sheeting | Timber Boards & Shelving | Builders South Africa
Option 2
Sized as is.
Isowall Polystyrene (915 x 610 x 15mm) | Polystyrene | Boards & Sheeting | Timber Boards & Shelving | Builders South Africa
Option 3
Sized as is.
Polystyrene Ceiling Tile | Brights Online Store
Dimensions: 1220x610mm.
Isowall Under Surface Bed Insulation (2440 x 1220 x 35mm) | Polystyrene | Boards & Sheeting | Timber Boards & Shelving | Builders South Africa
Option 2
Sized as is.
Isowall Polystyrene (915 x 610 x 15mm) | Polystyrene | Boards & Sheeting | Timber Boards & Shelving | Builders South Africa
Option 3
Sized as is.
Polystyrene Ceiling Tile | Brights Online Store
Plywood
Ideally want to go as large as possible (2440x610mm) whilst maintaining the 4:1 aspect ratio as identified by Veleric in #1395. Clamping from the bottom using natural rubber to dampen (old motorcycle inner tubes) as per Burntcoil’s design in #1797. If this is too floppy - side support/damping as per Burntcoil’s post #1046.
Interested to see what effect painting with boiled linseed oil would have on the plywood. Expect it would increase the surface hardness?
Option 1
Would like to try this 3mm pink beech, but supplier is far away.
https://www.boardmaster.co.za/pink-beech-plywood.html
Trying to see if I can source via: https://theboardstore.co.za/
Option 2
3mm hardwood exterior plywood
https://www.citiwood.co.za/product/hardwood-ply-exterior/
Option 3
4mm Birch plywood
https://itmwoodshop.co.za/product/birch-plywood/
Aluminium faced PVC foamWould like to try this 3mm pink beech, but supplier is far away.
https://www.boardmaster.co.za/pink-beech-plywood.html
Trying to see if I can source via: https://theboardstore.co.za/
Option 2
3mm hardwood exterior plywood
https://www.citiwood.co.za/product/hardwood-ply-exterior/
Option 3
4mm Birch plywood
https://itmwoodshop.co.za/product/birch-plywood/
High potential WAF as these can be printed on.
Available in: 100x750x3mm (0.21mm thick Alluminium)
https://www.maizeyonline.co.za/rigid-substrates-sheets/i-bond-signage/i-bond-brush-silv-3-primer-3mm-0-21-indoor-coalbspr31000750i--3%3dos
Honeycomb cardboard
As with the plywood, curious what effect painting with boiled linseed oil would have.
Available in: 1000x1200x(20/30/50/90)mm
Think I’ll go for the 20mm. Use sized as is.
https://ubusi.co.za/ubusi-panels/
PLA 3D print
Got filament, will print. Is there anything in the literature suggesting that the front face of the DML should be flat? Thinking of printing an irregular shape.
Canvas picture frame
Got some lying around. Will build ala OffGridKindaGuy’s design recommendation in #913.
Probably a good idea to build some acoustic panels to improve room acoustic where DMLs are to be measured and used.
https://roofinsulations.co.za/product/50mm-ecose-energy-batt-price-64kg-density/
Measurement Equipment
Amplifier
Plan on buying some cheap TPA3116D2 based amplifier boards. If this hobby becomes long term – hopefully upgrade to one of xrk971’s TPA3255 based designs (or similar).
https://www.robotics.org.za/XH-M542
Microphone
MiniDSP UMIK-1
https://www.parts-express.com/minidsp-umik-1-omni-directional-usb-measurement-calibrated-microphone--230-332
DSP
MIniDSP 2x4 HD
https://www.parts-express.com/minidsp-2x4-hd-usb-dac-digital-signal-processor--230-324
Measurement setup
- REW
- pink noise
- mic 1m from DML
- Psychoacoustic smoothing
I’m guessing it would be very beneficial to do these measurements outdoors to avoid room modes interfering. Will need to see if the wind and my neighbours can cooperate 😛
Sorry for the long delay, due to work offshore and covid, my project took a back seat. The panels arrived and I tested them with DAYTON AUDIO DAEX25FHE-4 exciters. I was disappointed with the results. There wasn’t enough volume and the sound was quite tinny (not a very good explanation!). The carbon fibre/foam composite boards really ringed when you tapped them.
I was testing the exciters on materials I had lying around the house and placing them on my acoustic guitar sounded a lot better than the carbon panels.
Thankfully, carbon composites kindly accepted the return of the panels for a full refund.
Back to the drawing board. Start with the tried and tested materials. 🙂
Hi moldie - welcome to the forum. Looking forward to hear about your findings - you sure have a lot lined up. Good luck with all those orders - the shipping and our customs are awfully slow and frustrating currently.
Thanks twocents. Yes I'm not holding my breath on getting it before at least mid September. Lots of tests yes, side effect of lockdown life - suddenly having tons of free time.
I've seen this asked before over the years but not seen any answers...has anyone tried a bass shaker (i.e., tactile transducer) on a panel (especially an XPS/EPS) to produce base sounds?
Geosand, I don't think anyone here has tried this AER drive that has been mentioned in earlier posts. Probably because of the high cost! But, it appears to me to use a 'bass shaker' for the low frequencies, and a tweeter for the highs. AER seem to think it works.
bbx - AER Loudspeakers
bbx - AER Loudspeakers
I have tried it with a cheap bass shaker specifically this model:
Dayton Audio TT25-8 PUCK Tactile Transducer Mini Bass Shaker 8 Ohm
The results weren't promising it produced bass but the volume wasn't noticably higher then with a normal exciter. I used it on a large XPS panel and on wood.
But I got my measuring mike yesterday so I will probably do a few more tests in the future. Maybe a two way system with a shaker and a normal exciter using a XO will be a viable option on larger panels.
- Leonard