Thank you for this synthesis. I see I am almost in your steps and I fully understand your description of the result. This is really encouraging to continue with this type of loudspeaker. Probably I have missed posts like yours in this thread. It would be great to have other feedback (or link back to posts), if possible to "exotic or more calculated panels" as you mentioned. Thanks again to have open the door to your system.
Christian
No problem. I have read every post in this thread up until a couple of months ago. So much good information if you can take the time to wade through it.
Anyway, the more "exotic" builds I speak of are people who were using composites and cnc machines to carve intricate panels, or using carbon fiber and resin and stuff to make their panels.
As for the "more calculated" part, I feel like I am just following the big crayon guide to DML building. I use basic placements and a lot of trial and error. There are a lot of guys in this thread who understand the science behind audio and acoustics far better than I do, and it shows, and put a lot more technical effort into understanding what's happening and trying to optimize their projects. I try to read the white papers and stuff and I maybe understand a small percentage of it before my eyes cross. I do some very basic RTA work but not to the extent of the big brains in here, and I'm not doing crazy modeling or going out of my way to source fancy materials or drivers.
Like, XRK971 is on a whole different level when I comes to technical understanding, and it shows in his enclosures and stuff. I follow his foam builds and horn loaded projects and am just in constant awe. He and guys like Burnt Coil, chdsl, spedge, and plenty of others have dropped a lot of technical papers and valuable working knowledge in here over the years that's very useful, and often over my head. I just feel like I am getting by in comparison. But hey, I got a pair of panels I'm really pleased with out of it.
I have lots of posts in the past and I spew streams of consciousness and ramble about small victories and discoveries, so it is probably easy to follow my journey. If not, I am always down to answer questions. I tried all of the simplest "slap an exciter on a substrate" experiments, just to hear them, even if people said they were a waste of time. And I did a lot of overcooked builds, including 2 and 3 way hybrid panels with mixed substrates and passive crossovers trying to get low and high extentions that didn't seem possible in a single panel. So I'm a wealth of what not to do as well as what works. LOL
Negative Ghostrider,
It's a valuable asset to the forum to be a repository of what NOT to do, as well as what TO do. Helping others to not go down the same rabbit hole is just as valuable as showing what are not rabbit holes.
Except for the electronics and my subwoofers, my whole audio system comes from diyAudio, both here and from XRK971's foam enclosures. I built the Nautaloss I, the XKi and the curved-sided double chamber bass box, all from the mind of XRK971, who I agree is a real genius, plus a set of Off-grid's canvas panels. Spedge was my guiding force there, and he is THE guru of DML, in my book. He is also a very valuable asset on what not to do, and he has stacks of prior panel experiments to prove it. In my younger days, I had 42 drivers surrounding me when I listened to my music, driven by home-built custom electronics from Revox and Nagra tape decks. It's a much longer span of time than I'd like to think about, but I like my system now about as much as I did back then (when I still had decent hearing!)
It's a valuable asset to the forum to be a repository of what NOT to do, as well as what TO do. Helping others to not go down the same rabbit hole is just as valuable as showing what are not rabbit holes.
Except for the electronics and my subwoofers, my whole audio system comes from diyAudio, both here and from XRK971's foam enclosures. I built the Nautaloss I, the XKi and the curved-sided double chamber bass box, all from the mind of XRK971, who I agree is a real genius, plus a set of Off-grid's canvas panels. Spedge was my guiding force there, and he is THE guru of DML, in my book. He is also a very valuable asset on what not to do, and he has stacks of prior panel experiments to prove it. In my younger days, I had 42 drivers surrounding me when I listened to my music, driven by home-built custom electronics from Revox and Nagra tape decks. It's a much longer span of time than I'd like to think about, but I like my system now about as much as I did back then (when I still had decent hearing!)
Amen to all of this, man. I have been wanting to build one of his Light as Air SLOB boxes for a long time. I considered making one (or a Voxel sub) to be the .1 sub for my DMLs, but I already had the velodyne laying around, and no real room for another sub 😅
Spedge is certainly a shining star in this group as well.
Negative Ghostrider,
When I lived in Germany in the '70s with that very bass-heavy system, I would play a 19Hz test tone at about a 6 volume level, then go out on my balcony to watch the neighbors come out on theirs to see what kind of heavy truck convoy was going by. Needless to say, I love good bass!
When I lived in Germany in the '70s with that very bass-heavy system, I would play a 19Hz test tone at about a 6 volume level, then go out on my balcony to watch the neighbors come out on theirs to see what kind of heavy truck convoy was going by. Needless to say, I love good bass!
Negative Ghostrider,
You know I was kidding when I said, "Just one", right? I read up on the Monolith sub. That is a monster! I can see why you like it. Right now, I only have 2 orphans from nice 5.1 systems. They do a good job for my needs. I can't turn my system up loud enough to justify anything else, due to my living with my daughter. Being disabled sucks! 18 surgeries in the past 25 years, 6 in only the last 2, with at least 3 more scheduled. Oh well, my country called, and I answered.
You know I was kidding when I said, "Just one", right? I read up on the Monolith sub. That is a monster! I can see why you like it. Right now, I only have 2 orphans from nice 5.1 systems. They do a good job for my needs. I can't turn my system up loud enough to justify anything else, due to my living with my daughter. Being disabled sucks! 18 surgeries in the past 25 years, 6 in only the last 2, with at least 3 more scheduled. Oh well, my country called, and I answered.
Probably not the place to ask, so maybe talk me out of it.
I have 4 downfiring ceiling hung panels and a sub. The panels go from about ~300Hz up to about 11KHz, then need heavy DSP lifting to cover the rest up top. They do sound great though.
I was looking at the Parts Express Christmas catalog (sidebar- this story will illustrate why they need to bring back the big driver table) and I came across these planar transducers:
https://www.parts-express.com/GRS-PT6825-8-8-Planar-Mid-Tweeter-8-Ohm-272-126
They cover 250-20KHz in a much more linear fashion than my panels, and are actually not terrible off-axis... and with my panels being downfiring, pretty much all listening is off-axis. My system sounds great, but I've always been a little bothered by the fact that all frequencies below ~250Hz or so are basically handled by 1 sub. So here is where the magic comes in. My panels are 2x2 feet. So I can easily fit a large or several small woofers on the panel and cover nearly full range. I would still keep the sub but only have it cover up to ~60-80Hz or so. The only question and challenge respectively is I won't have much clearance- maybe 6"?- so I don't know how that will affect bass response (and I wonder if that might be the problem with my panels- I never tested them in the open)- and of course finding a light, shallow driver that will cover the frequencies I want in an open baffle config. I do feel like those OB panels would require way less heavy lifting from my DSP...... possibly no DSP at all which would be cool. But I don't know.
I know this kind of goes against everything this thread is about................... but I get bored and like to switch things up a bit. And you guys understand DML magic so you know where I'm coming from to a degree. I wanted to experiment with different materials and all that but I just don't have the time........ looking for something I don't have to think about.
I have 4 downfiring ceiling hung panels and a sub. The panels go from about ~300Hz up to about 11KHz, then need heavy DSP lifting to cover the rest up top. They do sound great though.
I was looking at the Parts Express Christmas catalog (sidebar- this story will illustrate why they need to bring back the big driver table) and I came across these planar transducers:
https://www.parts-express.com/GRS-PT6825-8-8-Planar-Mid-Tweeter-8-Ohm-272-126
They cover 250-20KHz in a much more linear fashion than my panels, and are actually not terrible off-axis... and with my panels being downfiring, pretty much all listening is off-axis. My system sounds great, but I've always been a little bothered by the fact that all frequencies below ~250Hz or so are basically handled by 1 sub. So here is where the magic comes in. My panels are 2x2 feet. So I can easily fit a large or several small woofers on the panel and cover nearly full range. I would still keep the sub but only have it cover up to ~60-80Hz or so. The only question and challenge respectively is I won't have much clearance- maybe 6"?- so I don't know how that will affect bass response (and I wonder if that might be the problem with my panels- I never tested them in the open)- and of course finding a light, shallow driver that will cover the frequencies I want in an open baffle config. I do feel like those OB panels would require way less heavy lifting from my DSP...... possibly no DSP at all which would be cool. But I don't know.
I know this kind of goes against everything this thread is about................... but I get bored and like to switch things up a bit. And you guys understand DML magic so you know where I'm coming from to a degree. I wanted to experiment with different materials and all that but I just don't have the time........ looking for something I don't have to think about.
Yeah, it's a heck of a value. I run 9.2 Atmos in my theater room with the monolith and the velodyne. I know it's frowned upon to run unmatched subs but the end result sounds fine to me. Probably thanks to DSP.
Sorry to hear of your pains, but thanks for your service.
Hello Jaxboy,
Your post sent me almost where I stopped my linear reading of this thread to start my own experiments. It was about the time the fork design with canvas appeared (see Offgrid's posts). Now I better understand DML, we (my wife and I) appreciate their sound, it is time to continue experimenting... I have a pair of exciters left to fit in a canvas.
Your post proposes a solution with acrylic painting in order to have a nice looking (or at least a desired color) which important to allow the speaker to sit a long time in our living room( audio and styling!).
I understand the basics of the canvas design. I would like to have some help on points that are not so clear to me :
- what are the pad in canvas and the exciter in the pad position (my second DML prototype was fully centered and the result not good!) ?
- what about the adjustment of the tension of the canvas ?
- do we need some damping to avoid noise at canvas / frame contact?
- Are there some data (experiments) that link the canvas dimensions to the low frequency obtained?
Thanks
Christian
homeswinghome,
I would strongly recommend that you review Spedge's posts, as he is who I consider the expert on DMLs. I followed his advice in setting up my panels, except for substituting the diluted acrylic paint/water (about 1:3 or so, which still provides deep color without the weight of undiluted paint) for the diluted pva/water solution. My wood exciter mount is about 4x6", with rounded corners, and is made from standard room paneling, as used in homes as wall covering instead of paint or wallpaper. I thinned it by approximately 1/3 by sanding off the outer ply on both sides. It is centered on the canvas. Artists routinely tighten their canvases by spraying them with water, so in addition to tightening the canvas, the acrylic paint/water or pva/water solution works to provide the hard surface needed for the DML to be most effective. Most canvases have slots in the frame that allow you to insert wedges at the corners to further stretch the canvas if necessary. My panels are still drum-tight with no wedges after several months of play, though admittedly at reduced volume. My panels are 12x16", and I was getting reliable 40Hz reproduction. However, I inserted a 100uf capacitor in their positive leads to limit the frequency range to 50Hz, as heavy-attack bass music can make the canvas vibrate so hard that the excitor will bottom against the spline. In normal music, this would not be necessary, but I am a bass freak, so I opted to take that problem off the table and use the sub to do that duty. I am very satisfied with the musical quality of my panels. I also run 2 of the 3 sets of the previously mentioned foam-core speakers that were designed by XRK971, as I had just made them, and I couldn't see putting them in the closet. The 3rd set is used with the TV. This gives me room-filling sound, as the speakers are set up it the 4 corners of my smallish room, and the DMLs are in the middle of the wall that I face when I am at the computer, which is most of the time. With the DMLs being so close to the wall, I have drapes and melamine foam panels behind them to reduce the rear radiation. Being unable to play them at the volume level I would ordinarily, the extra speakers work to fill the room with sound without the loudness, a suitable work-around for my situation. Too, the Nautaloss speakers play to below 40Hz easily, augmenting the sub nicely. I hope this helps you in setting up yours.
I would strongly recommend that you review Spedge's posts, as he is who I consider the expert on DMLs. I followed his advice in setting up my panels, except for substituting the diluted acrylic paint/water (about 1:3 or so, which still provides deep color without the weight of undiluted paint) for the diluted pva/water solution. My wood exciter mount is about 4x6", with rounded corners, and is made from standard room paneling, as used in homes as wall covering instead of paint or wallpaper. I thinned it by approximately 1/3 by sanding off the outer ply on both sides. It is centered on the canvas. Artists routinely tighten their canvases by spraying them with water, so in addition to tightening the canvas, the acrylic paint/water or pva/water solution works to provide the hard surface needed for the DML to be most effective. Most canvases have slots in the frame that allow you to insert wedges at the corners to further stretch the canvas if necessary. My panels are still drum-tight with no wedges after several months of play, though admittedly at reduced volume. My panels are 12x16", and I was getting reliable 40Hz reproduction. However, I inserted a 100uf capacitor in their positive leads to limit the frequency range to 50Hz, as heavy-attack bass music can make the canvas vibrate so hard that the excitor will bottom against the spline. In normal music, this would not be necessary, but I am a bass freak, so I opted to take that problem off the table and use the sub to do that duty. I am very satisfied with the musical quality of my panels. I also run 2 of the 3 sets of the previously mentioned foam-core speakers that were designed by XRK971, as I had just made them, and I couldn't see putting them in the closet. The 3rd set is used with the TV. This gives me room-filling sound, as the speakers are set up it the 4 corners of my smallish room, and the DMLs are in the middle of the wall that I face when I am at the computer, which is most of the time. With the DMLs being so close to the wall, I have drapes and melamine foam panels behind them to reduce the rear radiation. Being unable to play them at the volume level I would ordinarily, the extra speakers work to fill the room with sound without the loudness, a suitable work-around for my situation. Too, the Nautaloss speakers play to below 40Hz easily, augmenting the sub nicely. I hope this helps you in setting up yours.
Thank you for your quick and detaiedl reply Jaxboy. The answers I received encourage me diving again in this thread... what I did to set up my current design and what I am doing for the next steps.
May I ask for an additional precision : what is the exciter position ? dead center? off center?
christian
regarding canvas DML speakers, do we need them to be in circular shape or regular rectangular shape?
does they work like a normal speaker where the stretched canvas acting like a speaker cone?
is this the reason they are giving good bass till 40Hz , acting like a big size cone regular speaker?
does they work like a normal speaker where the stretched canvas acting like a speaker cone?
is this the reason they are giving good bass till 40Hz , acting like a big size cone regular speaker?
I hadn't thought about it before, but canvas stretched in an embroidery hoop would be a novel and effective way to make a DML! You'd just have to be careful that you stretch the canvas equally from all sides. I'd recommend that you sand the top of inner ring so that there is a taper towards the inside, to prevent the canvas from slapping against it with the heavy bass notes, and to prevent print-through of its shape onto the canvas. A 16" or so ring set would seem to be ideal. Also, don't forget to coat both sides with either pva or acrylic paint, diluted to about 1:2 -1:4, to further shrink the canvas and to give the canvas a hard surface. A 3-5" circle of thin light wood for the exciter mount would be about right. Polishing and/or staining the outer wooden ring would give a nice touch, too. My rectangular canvas DMLs played 40 Hz with no problems, but to prevent slap from the heavier bass notes, I added a 100uf capacitor in the positive lead, to limit bass excursion to 50Hz, using a sub to play those lower notes. Good idea!
Sarath.
I have made the hoop and the canvas art panel,and personally if I was working from scratch,I would go for the art panel.
it's all pre made and stretched to about the right tension, you only have to attached the 6x4inch 3mm balsa ply.
I also prefer the heavier frame of the art panel.
The response below about 100hz is ,I believe, helped by the exciter panel resonance ,which causes a large hump in the response.
this is easy to EQ or roll off to a sub.
Yes they are acting very similar to a cone driver at these frequencies , but I do feel there is more going on in the dml mode too ?
There does not seem to be as much cancellation from the sides, which helps the in room response.
I have no art panels up and running at the moment so cannot measure this and compare, only the posts and recordings already posted.
If using very near field with not too strenuous music I would think they would give very good results.
But I wouldn't use them for driving a room with heavy bass, I would use a sub to take the strain off of the panel,as you would with any ordinary good quality full range driver.
Steve.
I have made the hoop and the canvas art panel,and personally if I was working from scratch,I would go for the art panel.
it's all pre made and stretched to about the right tension, you only have to attached the 6x4inch 3mm balsa ply.
I also prefer the heavier frame of the art panel.
The response below about 100hz is ,I believe, helped by the exciter panel resonance ,which causes a large hump in the response.
this is easy to EQ or roll off to a sub.
Yes they are acting very similar to a cone driver at these frequencies , but I do feel there is more going on in the dml mode too ?
There does not seem to be as much cancellation from the sides, which helps the in room response.
I have no art panels up and running at the moment so cannot measure this and compare, only the posts and recordings already posted.
If using very near field with not too strenuous music I would think they would give very good results.
But I wouldn't use them for driving a room with heavy bass, I would use a sub to take the strain off of the panel,as you would with any ordinary good quality full range driver.
Steve.
Hello Steve,
May I ask you 2 questions?
- Up to now I made panels with a width of at least 40cm and a height from 60 to 125cm. For each, there was a loss in the bass when I measure at the listening position compare to the proximity measurement (few cm in the exciter axis). By making indoor and outdoor measurement with my latest plywood panel (see post 4116), I came to the conclusion it was an effect of the combination of the front and the rear wave in room (the outside FR of the panel was pretty the same as the proximity one). My understanding is the frequency where the level starts decreasing increases when the panel size is reduced (but I think I have no real proof of that!). From your tests on canvas, seems not... Do you have some explanation or better way to predict this behavior ?
- You have no canvas panels working for now... May I ask what is working for now? Forget this question if it intrusive!
Christian
Hello all,
After the satisfaction of a first pair of plywood panel, I restarted deep diving in this thread, taking new notes. You will find in the attached file links and information about it. It is not for sure an academic objective synthesis but if like me you are looking for reference realizations or the time period or page rank for a post, it may have a utility. If not, not a problem... Additional information, suggestion for reference realizations or posts are welcome. I can post the original open office file if needed.
Christian
After the satisfaction of a first pair of plywood panel, I restarted deep diving in this thread, taking new notes. You will find in the attached file links and information about it. It is not for sure an academic objective synthesis but if like me you are looking for reference realizations or the time period or page rank for a post, it may have a utility. If not, not a problem... Additional information, suggestion for reference realizations or posts are welcome. I can post the original open office file if needed.
Christian