How do you seal between the mounting plate and waveguide? PLA plastic.
I would like it to have it zero thickness but still be detatchable for driver removal. A very thin rubber/foam gasket or some paste sealant? What product if so? Or is it just to over-do it? Will it be air-tight enough if 4-8 bolts are used to screw it together? (4 are shown below). The waveguide will boxed and woofers will be atatched later on, so I don't want the waveguide to become leaky.
Thanks/
Petter
I would like it to have it zero thickness but still be detatchable for driver removal. A very thin rubber/foam gasket or some paste sealant? What product if so? Or is it just to over-do it? Will it be air-tight enough if 4-8 bolts are used to screw it together? (4 are shown below). The waveguide will boxed and woofers will be atatched later on, so I don't want the waveguide to become leaky.
Thanks/
Petter
I used wax paper between machined surfaces to replace Altec's 0.074"/1.88 mm treated cardboard gaskets; align honed the assemblies to deal with the mismatched horn tapers and I've seen some early systems using leather gaskets too.
Both sets of compression drivers I own have a gasket already glued to them. I assumed this was normal ?
Rob.
Rob.
Is it certain that a stiff rigid connection is optimal?
https://www.diyaudio.com/community/threads/hornflower-2-way-point-source.386363/page-4#post-7111646
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https://www.diyaudio.com/community/threads/hornflower-2-way-point-source.386363/page-4#post-7111646
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Mine also has some foam glued to it:
Bottom of 3d printed mouth (PLA) is already quite flat.
How much air will leak through tiny holes instead of through the large hole it is supposed to?
Bottom of 3d printed mouth (PLA) is already quite flat.
How much air will leak through tiny holes instead of through the large hole it is supposed to?
Great info guys, Thanks a lot! I've gotten inspiration.
I think the surfaces are very flat, but it is always good to learn from the community.
Speakerbob, the driver I have have no sealing foam. It is a dome tweeter.
I think the surfaces are very flat, but it is always good to learn from the community.
Speakerbob, the driver I have have no sealing foam. It is a dome tweeter.
In that case I would cut a thin rubber gasket. Try and find a punch to get an accurate circle.
Rob.
Rob.
In case your CAD pictures are not just for illustration, I don't think it is a good idea to put waveguide with roundover into a box.
Anyway, if both WG and driver faces are sufficiently smooth and flat, use thermal grease. Cheap, non-drying kind - zinc oxide in silicone oil. We use it to both seal and improve thermal hanling of PA divers on aluminium waveguides. As your design is unconcerned with power handling, any thin powder in silicone oil will make a good non-drying sealant. Like talc or titanium white, whatever is readily available.
Anyway, if both WG and driver faces are sufficiently smooth and flat, use thermal grease. Cheap, non-drying kind - zinc oxide in silicone oil. We use it to both seal and improve thermal hanling of PA divers on aluminium waveguides. As your design is unconcerned with power handling, any thin powder in silicone oil will make a good non-drying sealant. Like talc or titanium white, whatever is readily available.
The flange should be sealed and sanded flat. Revell Plasto is great, but acrylic wood putty would do as well. As for the gasket material, I still have not found easily attainable material.
Oh, really good! Makes a neat, hopefully invisible seal.
Thanks for the concern about boxing the wg. The rear will be 3d-printed too, so they will merge nicely.
I wouldn't use any of those compounds if it will touch the surround where it is glued to the chassis. Wouldn't want to deteriorate the glue or the surround. In fact, if the surround is the highest part of the face, it may do the sealing just fine. I haven't verified that, but I think it should be the case if the waveguide is pressed against that part of the surround.
Silicone (polydimethylsiloxane, precisely speaking) is inert. So inert you could eat it (E900 additive). We use it to improve sealing on treated cloth surrounds, when vinyl acetate polymers are for some reason unsuitable (to keep Rms low, for example), or on rubber surrounds to provide some degree of protection against airborne sulphur.
The tweeter i am about to mount wg to, has its surround mounted on the frontplate. So to get a mechanical tight fit (no air layer) i cut a shim from japanese paper 0.16mm thick. I do not know how and how much the wg flange will deform when mounted tight but will see.
Thanks, I've found silicone grease to source locally.
I've also found this gasket material, 0.4 mm thick. Problem solved then. Only to test the two.
https://www.biltema.se/bil---mc/bil...pluggspackningar/packningsmaterial-2000017981
I've also found this gasket material, 0.4 mm thick. Problem solved then. Only to test the two.
https://www.biltema.se/bil---mc/bil...pluggspackningar/packningsmaterial-2000017981
Question: how sensitive is the waveguide functioning to thickness of baskets/shims?
So if f.i. 0.5mm of gasket is placed will the tweeter response change unacceptable?
So if f.i. 0.5mm of gasket is placed will the tweeter response change unacceptable?
20 kHz is 17.2 mm. So I expect the response to be unchanged. Otherwise, I can always reduce the mounting plate with 0.4 mm to be on the safe side.
I have used chamois lether to great success. It compresses to almost nothing.
//Anders
//Anders
I use thing yoga mats for all my driver sealing needs, really handy material. Can be cut to size.
Thanks, so did mine. I redesigned the mounting plate. The ring marked with the arrow will seal towards the surround as the original mounting plate does.
Between the mounting plate and waveguide, several good suggestions have been given by others.