I’m looking at making a pair of distributed mode loudspeakers to mount in my room because they look cheap and fun to make and I’m poor and bored. Win-Win
Anyway. I was wondering if anyone has any tips or info on mounting?
I saw in This Video they used cotter pins in the foam board with fishing line to hang them up vertically. I was wondering if I could mount them from my ceiling but horizontally. How directional are they and would they just not work if I mounted them that way?
Some guys at my hackerspace built a pair of these, and they work amazingly well. I was shocked, I didn’t expect them to work at all, but the sound really fills the room in an interesting way. I’m surprised they aren’t more popular.
I moved away, but I still get the emails. They’re doing… okay. COVID wounded, but not killed (yet). They’re very much more on the DIY/community end of the spectrum, so the community has helped keep them alive. I think all of the “professional” makerspaces all got killed off.
It’s a damned shame. A load of us were on a call list for non profit repair shops in the region but that’s dried up too as the shops are "non essential. "
I was hoping to find an AI buddy to look into a silly idea of using the tiny rules generated by a large AI system on something like an esp32 or esp32 cam to act as a vocal/visual MIDI composer and controller. The object was so I can compose without my hands (im more a crumble than a cripple these days): Saying “computer give me a 4/4 stave at 120bpm, call it bass, set key to A minor. Start on the third beat with a D .record. bom bu bu bom” .
I still have the cigarette packet with my notes if anyone’s interested
The directional question is fairly moot as its the board vibration that creates the sound and both sides vibrate. Many concert halls use the same idea but when horizontal they like to curve the plane to prevent a column of sound and direct reflection from the floor which can create nodes of silence and greater amplitube.
Bending acoustic ceiling tiles is easy. Leave them out in the rain with a brick in the middle then wait weeks to dry them or contact a local ceiling tile company and ask for any bent or bowed stock.
Oddly enough ceiling tiles make great crowd microphones and I have found no need for expensive speaker drivers when you use piezo sensors from the building trade (the laminate foil ones as opposed to brass disc type)
Do you happen to know much about what they used or anything? I was just going to use those dayton exciters and 2 XPS foam boards sand them down, maybe a light black spray and mount them to my ceiling with cotter pins and fishing line.
I’m not sure about this foam stuff, though if the guide says it works then I’m sure it will, but I’m pretty sure they just used some thin particle wood that was lying around the shop. I don’t know what drivers they used but I know they didn’t cost all that much.
I think the dimensions of the boards was more important than the material.
There is an advantage to using professional drivers but the downside is that they are operating outside their normal field of use (wibbiling cardboard cones and laminates).
Id urge you to test your sheets with simple piezo drivers or cheap speaker drivers first. Just mounting a pro driver "incorrectly " can ruin it’s response. It’s easy to stick a cluster of piezo to a sheet of ceiling tile and make it sound great but the inverse of sticking ceiling tile to a posh driver has a high probability of sounding like a vibrating phone in a shoe box.
Rule no#1 in sound design is function before fidelity. (Also known as steal what works)
Note all sound design rules are numbered as they come to me and have no connection to any official sound design rules published prior to me making them up.
Convex (bending out in the middle) to distribute the sound and concave (bending in in the middle) if you want to focus the sound in a particular direction. (Distance shortens exponentially so no need for big curves : unless you want a speaker that only works when you stand next to it. Some Art galleries use these and most engineers try not to giggle when invoicing for this remarkable kit) @BlackDeath has brought up a very important point and that’s the dimension of the sheet. Too big and you’ll get null points forming on the sheet that mute the overall vibration of the board. Too small and you get both interference on the surface and wash as the frequency of the sound changes.
Simplest method to test the diameter is to use a pencil with a piezo attached to it with the output going into a scope. Then you can perform touch tests to map dead zones or buzz.
Other good ideas are framing the boards. This is good for mounting / suspending (like a trampoline top) but also so you can add an initial tension to the frame that any audio Boffin will tell you increases the fidelity and volume (amplitude/ energy) of the applied vibration. (Its how drums, cymbals, guitar Soundboards and beaten bowls in a Dobro work)
Thanks for all the help everyone / @Farabide and @BlackDeath lol. I’ll have a look around for cheap materials and report back when I get something going!
How efficient are the panel speakers? They must take a bit of power to get them to move air. There are several audio engineers lamenting the drop in speaker efficiency over the years and comparing older little 20W systems that are louder than new 100W systems. I guess if power is cheap, go for it. I understand that horn speakers are a very efficient design and are really loud and not nearly as directional as it might seem. Oh, and big too.
Large diameter panels can be very loud with much less power. That said the effective range of that volume is not a efficient as cone or shaped compression speakers. This is why a panel can be used in a small room like an art gallery but you’ll never see them at am outdoor rock concert.
