Hey everyone,
Hope this makes sense:
I had a pair of Pensil 11s commissioned but the speaker holes weren't countersunk and I'm experiencing pretty bad baffle diffraction. I've remedied a lot of it by placing compacted wool around the drivers, however I'm looking for a permanent and better looking solution.
The cabinets are currently at a CNC/laser shop and he's figuring out a way to make the speakers flush with the cabinet.
Assuming we have to go with C:
Any help would be appreciated. See picture for a hopefully better clarification here:
Thanks in advance!
Hope this makes sense:
I had a pair of Pensil 11s commissioned but the speaker holes weren't countersunk and I'm experiencing pretty bad baffle diffraction. I've remedied a lot of it by placing compacted wool around the drivers, however I'm looking for a permanent and better looking solution.
The cabinets are currently at a CNC/laser shop and he's figuring out a way to make the speakers flush with the cabinet.
- Our plan A was to see if we could fit the built cabinets in the laser / CNC machine to accurately cut the 4.6mm required depth-- unfortunately neither machine had adequate height clearance to do this.
- Our plan B is to see if he can construct a jig to accurately countersink the existing speaker hole the required depth to flush mount the speakers without damaging the veneer.
- Our plan C is, as a last resort, to CNC a custom front panel to overlay on the front of the speaker cabinet to emulate a flush-mounted driver, which will then be veneered to match the existing finish, either with a hole cut in a 5mm panel or a thicker panel with the 5mm countersink CNC'd into it.
Assuming we have to go with C:
- What risks to audio quality will I be introducing by adding a solid 5mm panel to the front of the speakers to make the speakers flush with the cabinet? (assuming it's secured tightly and there's no gaps between the cabinet and the newly added front panel)
- If I have to go this route, given we have access to a CNC machine and laser, is there anything specific that would be beneficial to add to this panel, or is a completely flat panel ideal? (example: thickening the panel and CNCing a wave guide vs. just keeping the panel completely flat)
Any help would be appreciated. See picture for a hopefully better clarification here:
Thanks in advance!
I would just make a ring, outside twice the cone diameter, inside to fit speaker, 1/4" thick, tapered 1:3 at the outside. You can get 1/4" plastic "trim board" at the Home Depot.
When you say baffle diffraction you don't mention whether it is from the driver frame or the cabinet edges, but this is an opportunity to address both given that a thicker baffle can accept a larger roundover.
This front piece is also an opportunity to do constrained layer damping on your baffle.
This front piece is also an opportunity to do constrained layer damping on your baffle.
Apolgoies, PRR; I don't quite understand-- could you visualize it?
Is this close?
AllenB,
I should have clarified: this is for the driver frame, not the baffle itself. It's my understanding that the Pensil 11 case has a good synergy with the Mark Audio drivers with a regular cubic case, however I'm curious to what you had in mind? A rounded baffle does sound enticing and I've only heard good things. What is constrained layer damping?
Is this close?
AllenB,
I should have clarified: this is for the driver frame, not the baffle itself. It's my understanding that the Pensil 11 case has a good synergy with the Mark Audio drivers with a regular cubic case, however I'm curious to what you had in mind? A rounded baffle does sound enticing and I've only heard good things. What is constrained layer damping?
Sometimes a baffle shape distributes diffraction evenly, and response measurements will look good, however response measurements don't tell the whole story. Rounding the baffle is intended to reduce the diffraction in the first place.
It's unclear how much it will help with a full-range driver because they tend to focus the higher frequencies forward of the baffle, but there still are some inconsistencies with that for which rounding might help.
Constrained layer damping is about reducing panel vibrations.
It's unclear how much it will help with a full-range driver because they tend to focus the higher frequencies forward of the baffle, but there still are some inconsistencies with that for which rounding might help.
Constrained layer damping is about reducing panel vibrations.
Ah, yeah, that makes sense-- thanks for the clarification. I guess my concern is whether rounding the edge could have any detrimental effects, or if it's at least directionally a net positive? Sounds like the latter, yeah?
I just looked up CLD-- sounds cool! However I can't seem to find any agreed-upon ways to go about implementing the idea and it makes it seem like a precarious venture. Is my gut check right or is there a tried and true CLD design that could be incorporated into this build? 🙂
I just looked up CLD-- sounds cool! However I can't seem to find any agreed-upon ways to go about implementing the idea and it makes it seem like a precarious venture. Is my gut check right or is there a tried and true CLD design that could be incorporated into this build? 🙂
Baffle rounding generally doesn't hurt. I have noticed that when people here talk about adding it to an existing design, few will argue the benefits to the high frequencies but some might mention the potential for change in baffle step frequency, but this shouldn't be a concern and it's not likely to be significant.
I've had good results simply laminating cabinet walls using a thin layer of polyurethane adhesive. You could use a tile adhesive trowel to make it even. The polyurethane should feel a little like marshmallow. When you drop your hammer on a panel like this it doesn't ring.
I've had good results simply laminating cabinet walls using a thin layer of polyurethane adhesive. You could use a tile adhesive trowel to make it even. The polyurethane should feel a little like marshmallow. When you drop your hammer on a panel like this it doesn't ring.
Very cool-- do you have any reading material for CLD I could use to research, visualize, and potentially use to mock up something for the CNC and laser shop to add to the baffle addition? Or any pictures of what you've done with this method to your current speakers? 🙂
Also, is there a general roundness that I should be aiming for with the baffle? I know it's a matter of thickness of this additional piece-- I'm assuming just a perfect rounded taper connecting each edge?
Also, is there a general roundness that I should be aiming for with the baffle? I know it's a matter of thickness of this additional piece-- I'm assuming just a perfect rounded taper connecting each edge?
I didn't try too hard to find this thread, but one or two of the members there have some good knowledge on the subject - https://www.diyaudio.com/forums/mul...er-damping-mdf-ply.html?highlight=constrained
With rounding, larger works down to a lower frequency. For example if you want to get all high frequencies down to about 3k5Hz, you'd use a radius of 1".
With rounding, larger works down to a lower frequency. For example if you want to get all high frequencies down to about 3k5Hz, you'd use a radius of 1".
Plan B -
Creating an MDF template with a hole of the required diameter then hand routering the recess using a top bearing cutter or a template guide bush is pretty simple to do.
Creating an MDF template with a hole of the required diameter then hand routering the recess using a top bearing cutter or a template guide bush is pretty simple to do.
I can't speak about the diffraction. However, if you add a solid 5mm panel to the front of the speakers to make the speakers flush with the cabinet you will have the added benefit of reinforcing the cabinet, which is always good. I'd use hardwood ply rather than mdf. In your original drawing, "opt a" has this panel shaped to fit over/around the speaker (making it hard to remove). I'm not sure if this is by design or just the way it's drawn, but I would construct it so the speaker can be easily removed in the future if required.
Thanks for the info, everyone 🙂
CNC/laser shop is gonna get back to me this week. Re: the 5mm panel: it would definitely be solid wood, and apologies on the lack of mspaint skill for it haha; it's gonna be around the speaker ring as it would look if it were just a normal countersink
CNC/laser shop is gonna get back to me this week. Re: the 5mm panel: it would definitely be solid wood, and apologies on the lack of mspaint skill for it haha; it's gonna be around the speaker ring as it would look if it were just a normal countersink