You can water down vinyl silk or matt paint, similar to pva.
This will help keep the weight down and not damp the panel as much.
You could also give the panel a coat of pva to protect the panel from solvent paints.
Coating the panel in paint will reduce colouration in the panel similar to doping a paper cone speaker, for a smoother sounding response.
Epoxy has the opposite effect and brightens the sound giving a higher HF and a more lively sound.
The shiny XPS surface should not be sanded when Coating with Epoxy.
The thinned vinyl will run off of the shiny surface if not sanded.
If painting the whole panel, do not coat the area of the exciter coil , paint is not glue and can easily peal off the exciter.
The 50x50 mix of pva when the water has evaporated, will only leave a trace of pva on the panel.
The paint even when watered down will start to increase the weight, so it will damp the sound more.
To be honest, I would now only use thin Epoxy coatings on XPS, as thin as possible to keep the weight down.
With the right exciter this changes the XPS into a full range panel material with good sound.
Some pictures of my various vinyl painted panels.
The green panel is the epoxy coated panel, I used a small roller to apply this coat which is too thick I think.
If I did this in the future I would probably use the scraper method to help keep the weight down ?
Hope this is of some help.
Steve.
Attachments
I would say that's because it stiffens it much more and limits the LF output. I experienced exactly the same when I used rice paper and latex...I made the world's biggest tweeter
If you look at Open Baffle speakers, then the rear wave is not an issue. Extreme low bass frequencies are generated by simply moving a helluva lot of air.
All you really need is a surface of at least 600mm x 600mm, which is more than 2 x 15" drivers, and ensure you have a lot of BL driving it.
And speaking of BL, (@BurntCoil would be the authority on this): Is it worth comparing the total BL of multiple small drivers to the BL of a single 15" driver?
If it is, then we can start comparing the BL vs moving mass of exciter-driven panels with the BL/Mms of piston cones. This could be interesting.
If you go to full range cone forums, there is usually a discussion about what is the excepted frequency range of a full range cone.
Dml panels can exceed these specifications easily without a box.
40hz is easily attainable with my exciters at low levels , but only on music without exaggerated bass.
You need so much power in the very low frequencies, to drive the room.
My TLs do this so well in my room that I have not felt the need to use DMLs for this purpose.
I usually run my various panels down as low as possible but not much below 100hz, it all depends on the panel and the exciter one uses.
It is handy having the DML boost in the below 100hz area , which open paneled cone drivers do not have.
Although companies such as spacial audio seem to be making waves in the low frequency performance of open baffle speakers .
Steve.
Eucy.
I don't think the epoxy reduced the LF on my 5mm xps panel ?
Probably the opposite.
But then the 5mm xps is not that rigid.
You can make 1inch xps very rigid especially if you add fibreglass.
You could end up with something like an oversized B139.
A low frequency DML is very interesting, but for me not a priority.
I'm not even sure how much DML would be involved below 40hz on a small panel ?
Steve.
I don't think the epoxy reduced the LF on my 5mm xps panel ?
Probably the opposite.
But then the 5mm xps is not that rigid.
You can make 1inch xps very rigid especially if you add fibreglass.
You could end up with something like an oversized B139.
A low frequency DML is very interesting, but for me not a priority.
I'm not even sure how much DML would be involved below 40hz on a small panel ?
Steve.
two recordings of panels with and without subs.
the epoxy panel sounds like a small bookshelf speaker and needs the sub , the proplex panel sounds like a large speaker with very little difference in LF.
the difference in the sound in room was more noticeable as the microphones roll off below 50HZ.
the proplex panel could be a good sub panel with a more powerful exciter, maybe even full range from 20hz to 20k ?
steve.
the epoxy panel sounds like a small bookshelf speaker and needs the sub , the proplex panel sounds like a large speaker with very little difference in LF.
the difference in the sound in room was more noticeable as the microphones roll off below 50HZ.
the proplex panel could be a good sub panel with a more powerful exciter, maybe even full range from 20hz to 20k ?
steve.
Steve's cell-phone recording, played back through my PA panels (at which I'm currently raising several eyebrows. More on this anon.) presents the EPS with a very aggressive lower-midrange honk (+/-500hz?) that is distracting.
But the 'Proplex' sounds very good. VERY good indeed!
Obviously a cell-phone recording will introduce time delays and all kinds of reflections and echo and reverb and is going to pick up standing waves and room resonance and modes and nodes and will not give true picture of what the panels are actually doing.
The Youtube link above might give us all a nice reference source for comparison purposes. It's an excellent recording.
I suspect that my own panels might have developed a bit of a peak around 500hz, and this might explain why Steve's EPS panels sound so aggressive in them.
Please comment.
I have never reeeelly bought into the idea of 'running in' speakers of any kind.
In my experience, speakers perform the same they do when you buy them as when they're older, barring depleted wallets, hopeful psychological issues and perishing surrounds of course. Same as when you overhaul your old Cosworth racing engine just before a race, as opposed to racing it 3 months down the line when the valves and rings are stuffed to hell-n-gone.
I measured my 'Gig Panels' (4 x DAEX25Q-4's each in 2 x 1,400mm x 450mmx 5mm Twinwall panels) beginning Feb just after assembling them, and I was a bit 'meh'—they were a lot better, bandwidth-wise, than the high power 30HESFs and "32QMB-4 Mega-bass" drivers in the same panels. But I still had to EQ them quite a bit to make them palatable for general stage use.
This has changed.
I find I have to EQ them less and less to get the sound that I want.
I've just compared them to the measurements I did a month ago (after A LOT of very loud abuse) and there are differences. I stand corrected: Drivers DO need to be run-in.
And as you can see, there is definitely a 450hz peak that might disagree with any other signal source with a similar peak.
Oh. And check out the bass end... Unless I'm driving very loudly indeed on stage, I don't need a sub.
50hz on the bottom is wayy enough for almost everything I consume at home.
I have never reeeelly bought into the idea of 'running in' speakers of any kind.
In my experience, speakers perform the same they do when you buy them as when they're older, barring depleted wallets, hopeful psychological issues and perishing surrounds of course. Same as when you overhaul your old Cosworth racing engine just before a race, as opposed to racing it 3 months down the line when the valves and rings are stuffed to hell-n-gone.
I measured my 'Gig Panels' (4 x DAEX25Q-4's each in 2 x 1,400mm x 450mmx 5mm Twinwall panels) beginning Feb just after assembling them, and I was a bit 'meh'—they were a lot better, bandwidth-wise, than the high power 30HESFs and "32QMB-4 Mega-bass" drivers in the same panels. But I still had to EQ them quite a bit to make them palatable for general stage use.
This has changed.
I find I have to EQ them less and less to get the sound that I want.
I've just compared them to the measurements I did a month ago (after A LOT of very loud abuse) and there are differences. I stand corrected: Drivers DO need to be run-in.
And as you can see, there is definitely a 450hz peak that might disagree with any other signal source with a similar peak.
Oh. And check out the bass end... Unless I'm driving very loudly indeed on stage, I don't need a sub.
50hz on the bottom is wayy enough for almost everything I consume at home.
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I found the same thing on my cedar panels, but I came to the conclusion that it was the panels themselves that became 'broken in'. They do a lot more flexing and moving than the exciters so it made sense to me.
Are your panels polycarb or polyprop?
Eucy
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Well... In simple terms, my first goal is adequate bass...a subjective term I realise, but there'll be two panels so do I need the equivalent of two 15" drivers...I don't think so ...
But looking at BL figures (insofar as they are a rough guide to punch), 4 BMR's will give about 19 total, which is more than many large woofers.
Looking at areas...12" driver about 550mm2, 15" about 900...
So say we look at a panel 500x300 = 1500 mm2 = 3 times a typical 12" cone so the required excursion for 12" equivalency is only 1/3rd that of a cone driver.
A lot of other factors come into play but at least the potential is there from a basic point of view.
Worth a try?...absolutely
Andre.
That is the CD I was using.
I presume you are referring to the epoxy XPS not the small EPS panel on the left ?
I made this recording from my seating position 3m back from the panels.
The room is stacked up with boxes on both sides of the walls.
This was to show the in room bass response under normal- ish room conditions.
Plenty of room problems.
I always recommend using headphones as this gives more of a being there sound.
I would expect the recording to sound odd being played over another stereo system.
I usually try to get close to the panels, under 1m to minimise room problems
The proplex was a 2ft x2ft panel.
The XPS epoxy panel was 85cm x60cm.
I could hear an echo in the panel ,that was why I subsequently used smaller XPS panels to reduce this.
Some small weights might solve this problem?
I will have a look tomorrow when I get time.
Steve.
That is the CD I was using.
I presume you are referring to the epoxy XPS not the small EPS panel on the left ?
I made this recording from my seating position 3m back from the panels.
The room is stacked up with boxes on both sides of the walls.
This was to show the in room bass response under normal- ish room conditions.
Plenty of room problems.
I always recommend using headphones as this gives more of a being there sound.
I would expect the recording to sound odd being played over another stereo system.
I usually try to get close to the panels, under 1m to minimise room problems
The proplex was a 2ft x2ft panel.
The XPS epoxy panel was 85cm x60cm.
I could hear an echo in the panel ,that was why I subsequently used smaller XPS panels to reduce this.
Some small weights might solve this problem?
I will have a look tomorrow when I get time.
Steve.
They are polycarb.
They are lighter and harder than polyprop which I have tried and which I found to be unsatisfactory
Yep...I have yet to try Polycarb,. Steve wasn't impressed from memory...bright but plasticky???. Can't remember... Both he and I have quite good results from polypropylene... A bit soft without added measures but generally better than expected
Eucy
Yes, bright and plasticky indeed. But it's given me the best combination of HF response and efficiency so far.
I've damped the plasticky sound by applying a few layers of spray paint.
Eucy, Andre.
All materials have their trademark sound, it is what we do to minimise this and what we can put up with.
I have only tested the 1cm thick square fluted Polycarb sheet.
Which had a very hard bright sound ,I don't remember it being that efficient except in the hf ?
But I was only using my 10watt exciter.
The 4mm square fluted polypropylene panel does seem to have a sort of cardboard sounding coloration to it ,compared to the round flueted 6mm proplex panel.
The proplex sound is hard to pin down, or I have not been paying enough attention, but nothing has hit me in the face yet, apart from the usual problem of a heavy panel.
And this is a very heavy panel, that is why I am trying out the thin film on these two panels.
The round flueted proplex panel did surprise me, I was not expecting this sort of performance from such an over damped panel.
I expected it to sound over damped and dull with curtailed frequencies.
There is one slight problem I have found, which is where to buy the product!
I have had a look on the Internet, and cannot find any trace of it ?
Only square flutes , which probably means that if round flutes can be found it will be very expensive .
Steve.
All materials have their trademark sound, it is what we do to minimise this and what we can put up with.
I have only tested the 1cm thick square fluted Polycarb sheet.
Which had a very hard bright sound ,I don't remember it being that efficient except in the hf ?
But I was only using my 10watt exciter.
The 4mm square fluted polypropylene panel does seem to have a sort of cardboard sounding coloration to it ,compared to the round flueted 6mm proplex panel.
The proplex sound is hard to pin down, or I have not been paying enough attention, but nothing has hit me in the face yet, apart from the usual problem of a heavy panel.
And this is a very heavy panel, that is why I am trying out the thin film on these two panels.
The round flueted proplex panel did surprise me, I was not expecting this sort of performance from such an over damped panel.
I expected it to sound over damped and dull with curtailed frequencies.
There is one slight problem I have found, which is where to buy the product!
I have had a look on the Internet, and cannot find any trace of it ?
Only square flutes , which probably means that if round flutes can be found it will be very expensive .
Steve.
Tried it with good result. See https://www.diyaudio.com/community/...ll-range-speaker.272576/page-406#post-7224227
It’s a full range that playes from 30 to close to 20k. It’s used in a 40 sqm living room. Possible sound level can easily destroy your hearing…
It’s quite easy to eq it to a flat response. I think it’s possible to make it play down to 20 Hz, haven’t tried it yet though.
Thomas