After a lot of trial an error and wasted filament, I finally got a first unit assembled today!
Have not done response tests yet, but first listen was very promising!
Seems better by every metric. Noticeably more sensitive, stronger bass and tighter and punchier throughout the spectrum.
All parts are connected with TPU seals to ensure no distortion from the frame. The plate is held up by a thin TPU suspension to allow it to better transition to piston action at lower frequencies.
One small but important improvement is that the exciters are held up by TPU surrounds that are fixed to the frame, but they can just about slide in and out which means they will find they "natural" most relaxed distance from the frame, but are still supported enough to not sag I hope. With my previous version I was forced to get the distance exactly right when mounting the exciters.
Will get back with measurements!
Have not done response tests yet, but first listen was very promising!
Seems better by every metric. Noticeably more sensitive, stronger bass and tighter and punchier throughout the spectrum.
All parts are connected with TPU seals to ensure no distortion from the frame. The plate is held up by a thin TPU suspension to allow it to better transition to piston action at lower frequencies.
One small but important improvement is that the exciters are held up by TPU surrounds that are fixed to the frame, but they can just about slide in and out which means they will find they "natural" most relaxed distance from the frame, but are still supported enough to not sag I hope. With my previous version I was forced to get the distance exactly right when mounting the exciters.
Will get back with measurements!
Hi Leob,
Nice work that looks amazing, glad it is sounding good as well. Are you still using graphite EPS 20mm for the plate? How is the plate attached to the perimeter TPU filament?
Are you still using 4 panels per corner of this arrangement?
Nice work that looks amazing, glad it is sounding good as well. Are you still using graphite EPS 20mm for the plate? How is the plate attached to the perimeter TPU filament?
Are you still using 4 panels per corner of this arrangement?
Still using the same 20mm GPS but trimmed to a smaller dimension to give room for TPU perimeter without increasing the size of the speaker.
TPU is glued to the EPS using 3M Super 77 spray glue. Can be tricky to find an adhesive that sticks to TPU but does not dissolve EPS, but Super 77 seems to work really well.
Yes, will stick with four plates per sub, I had to push them very hard to match the subs, so the improved sensitivity is a welcome margin.
TPU is glued to the EPS using 3M Super 77 spray glue. Can be tricky to find an adhesive that sticks to TPU but does not dissolve EPS, but Super 77 seems to work really well.
Yes, will stick with four plates per sub, I had to push them very hard to match the subs, so the improved sensitivity is a welcome margin.
Size of frame is 496x360 and 50mm deep + extrusion for speakon connectors.
Assembly is made up of front, front seal, frame, plate perimeter/seal, and the back. Seals are printed in TPU and has grooves to fit into the PLA parts, and it is assembled as a sandwich with six 50mm M3 screws that goes into insets added to the front part.
Printed on an Elegoo Orangestorm Giga.
Assembly is made up of front, front seal, frame, plate perimeter/seal, and the back. Seals are printed in TPU and has grooves to fit into the PLA parts, and it is assembled as a sandwich with six 50mm M3 screws that goes into insets added to the front part.
Printed on an Elegoo Orangestorm Giga.
what exactly is TPU? sorry must have missed it in a quick scan through the past few pages
i've been contemplating having a go at making something with exciters.
i've been contemplating having a go at making something with exciters.
TPU is a flexible thermoplastic, basically a synthetic rubber, that can be printed on a 3d printer. Flexible and very strong and durable.
Hi Leob,
When you have a chance to test the new panels, it would be great to see a comparison between your old clamped mounting and the new TPU suspension.
I still think there is some merit in the point clamping for suspension as it can allow some physical tuning but for your usage I am sure you are running DSP so less of an issue.
When you have a chance to test the new panels, it would be great to see a comparison between your old clamped mounting and the new TPU suspension.
I still think there is some merit in the point clamping for suspension as it can allow some physical tuning but for your usage I am sure you are running DSP so less of an issue.
There are quite a few variables that have changed, so might be hard to determine how the suspension affects the performance.
But from my feeling the clamping has resulted in more problems than it solves. Yes, it will affect how free the plate is to excite at certain modes and hence affect the FR, but mostly because it will be fighting against some modes. I don't think that is an ideal way to address an uneven FR, then EQ might almost be preferable. I like the sound of a free plate apart from a couple of issues. First of all it can ring a bit resulting in a spacious but untight response. Also the swinging of the plate at low freqs muddies the bass. So my goal is just to dampen the plate a bit, which fixes both those issues.
Another problem I mentioned with clamping is that the plate is not free to act as a piston driver at lower freqs. A very soft clamping material lets the plate sag, causing strain on exciters, and hard clamping completely kills all piston action resulting in them struggling below around 120Hz.
But from my feeling the clamping has resulted in more problems than it solves. Yes, it will affect how free the plate is to excite at certain modes and hence affect the FR, but mostly because it will be fighting against some modes. I don't think that is an ideal way to address an uneven FR, then EQ might almost be preferable. I like the sound of a free plate apart from a couple of issues. First of all it can ring a bit resulting in a spacious but untight response. Also the swinging of the plate at low freqs muddies the bass. So my goal is just to dampen the plate a bit, which fixes both those issues.
Another problem I mentioned with clamping is that the plate is not free to act as a piston driver at lower freqs. A very soft clamping material lets the plate sag, causing strain on exciters, and hard clamping completely kills all piston action resulting in them struggling below around 120Hz.