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Re: skywave's 3Pi subwoofer build [message #71653 is a reply to message #71617] Sun, 04 March 2012 04:34 Go to previous messageGo to next message
Psychoacoustic is currently offline  Psychoacoustic
Messages: 75
Registered: May 2009
Viscount
Hope these photos give some perspective. Please excuse the filth- it's all part of the sonic tuning.

Showing spacer, grille, mounts, riser.
http://i38.photobucket.com/albums/e105/NormGunston/DSC_0159.jpg

Hard time finding veneer here.
http://i38.photobucket.com/albums/e105/NormGunston/DSC_0162-1.jpg
Re: skywave's 3Pi subwoofer build [message #71654 is a reply to message #71617] Sun, 04 March 2012 04:36 Go to previous messageGo to next message
Psychoacoustic is currently offline  Psychoacoustic
Messages: 75
Registered: May 2009
Viscount
Forward sub.
http://i38.photobucket.com/albums/e105/NormGunston/DSC_0166.jpg

Rear.
http://i38.photobucket.com/albums/e105/NormGunston/DSC_0168.jpg
Re: skywave's 3Pi subwoofer build [message #71655 is a reply to message #71649] Sun, 04 March 2012 07:59 Go to previous messageGo to next message
skywave-rider is currently offline  skywave-rider
Messages: 104
Registered: May 2009
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Wayne Parham wrote on Sat, 03 March 2012 21:21

You can take the gasket off if you want, but if you do, be sure to scrape it off completely and clean the surface, like you would do on an engine rebuild. Start with a completely smooth and clean surface for the new gasket. Otherwise, you may not have a good seal.

I guess I don't see the benefit in doing this. If you are concerned with the height from the baffle, wouldn't it be better to route a recess for the woofer to sit in?

About the mounting holes, and the portion of the surround that partially covers them, simply foke through that. It's just an artifact of assembly. You can cut it with a razor, if you want. But you can just poke the mounting screw into the hole too. There's no harm if that bit of material bends or tears.




Wayne,
Actually, the woofer arrived with no gasket at all on the bottom part of the flange. The top has a neoprene (maybe) gasket which is possibly be glued on. I don't want to mess with it. A thick paper or fiber gasket was taped to the top of that, for use on the bottom. So I have a clean surface on the bottom flange.

As far as the recess goes, I would love to do that but it will require a thicker baffle and more cost. The protection and aesthetic the recess offers is something to consider, though.

Thanks for the tips on the mounting holes. I managed to accidentally remove the surround on a PE woofer once with mounting screws, but that's a different animal I'm sure.

Re: skywave's 3Pi subwoofer build [message #71656 is a reply to message #71655] Sun, 04 March 2012 08:12 Go to previous messageGo to next message
skywave-rider is currently offline  skywave-rider
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Registered: May 2009
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Psychoacoustic,
Thanks for the photos. Your system looks formidable. Actually, I don't mind a raw finish or a utility finish. I could live with that for sure.

The detail of the spacer used on the grill mount assembly is great, and I can now see that shape is not very easy to make.

I admire your skills, and I would love to hear those cornerhorns.

Isn't it interesting how many avid hi-fi and horn-system fans there are in Japan?
Re: skywave's 3Pi subwoofer build [message #71658 is a reply to message #71655] Sun, 04 March 2012 08:54 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

skywave-rider wrote on Sun, 04 March 2012 07:59
Actually, the woofer arrived with no gasket at all on the bottom part of the flange. The top has a neoprene (maybe) gasket which is possibly be glued on. I don't want to mess with it. A thick paper or fiber gasket was taped to the top of that, for use on the bottom. So I have a clean surface on the bottom flange.

Of course, you're right. So sorry for the confusion! I was thinking of the pressed framed drivers that have the gasket glued on. Those are rather thin, and don't make much sense removing. But the cast drivers don't have them. You're talking about that extra gasket, loose in the box, the one that comes with the woofer.

The included unattached paper gaskets that come with the woofers are good. They double as spacers for installations where the woofer is mounted to a compression plate. But if you want a spacer and don't need the extra thickness, try making a gasket with PVC material. Like this:

http://www.pispeakers.com/Basshorn/Cutting_Gasket.jpg

Re: skywave's 3Pi subwoofer build [message #74599 is a reply to message #71658] Mon, 26 November 2012 16:09 Go to previous messageGo to next message
skywave-rider is currently offline  skywave-rider
Messages: 104
Registered: May 2009
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Wayne, your T-nut installation instructions should go into your FAQ thread if it isn't already. Stupid question, is Gorilla Glue going to hold the T-nuts? Or is epoxy, as you mentioned, the way to go?
Re: skywave's 3Pi subwoofer build [message #74600 is a reply to message #74599] Mon, 26 November 2012 16:18 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

Good catch, I'll add that T-Nut installation page to the FAQ right now.

I like using 5-minute epoxy but PL adhesive or Gorilla glue will work just fine too. The whole goal is to give 'em just a little more "stick". I've found that T-Nuts tapped in bend the prongs sometimes, so that leaves us with nothing holding them. But even when you pull 'em in as described in the "installation instruction" post linked above, they still just have the three or four prongs holding them in. The rasped ones hold better than the straight ones, but still, I've had them get loose over time. A dab of glue prevents this. It really stinks when you go to remove a woofer for whatever reason, and the T-Nut spins. So this is just extra precaution. I've never had a problem with a T-Nut that I added a dab of glue before installing it.

Re: skywave's 3Pi subwoofer build [message #74605 is a reply to message #74599] Mon, 26 November 2012 21:16 Go to previous messageGo to next message
steve f is currently offline  steve f
Messages: 236
Registered: May 2009
Master
Been following the thread. I personally don't like Gorilla Glue for mounting tee nuts. The glue expands as it dries, and you have to keep wiping off the excess. If you assemble the woofer wet, glue can get on threads, gaskets, etc. You will have one heck of a time removing the driver for servicing. Epoxy or non expanding glues work best.

Another way to insert tee nuts is to drive them in with a C clamp. No thread distortion at all.

Steve
Re: skywave's 3Pi subwoofer build [message #74607 is a reply to message #74605] Mon, 26 November 2012 22:00 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18670
Registered: January 2001
Illuminati (33rd Degree)

You're right that Gorilla glue and PL adhesive expand as they cure. But if you just put on a drop, just a smear of film, that kind of adhesive works great. That's all we want, really, just a dab. It adds extra hold and prevents the T-Nuts from backing out. But yeah, whether epoxy or PL adhesive, you have to be careful not to get it on the threads or anywhere else you don't want it.

Using a C-Clamp is basically the same approach I usually recommend, which is to pull T-Nuts in with a screw and washer rather than tapping them in with a hammer. I think the C-Clamp method is a fine way to do it too. The main thing is to apply a slow, even and straight pressure rather than with sharp impacts from a hammer, which tend to bend the tongs rather than driving them in.

My experience with high-power hornsubs is what drove me towards these methods. Prosound subs beat the hell out of stuff, and you would be suprised what that much vibration can do.

Most people won't punish their subs the way prosound hornsubs are, and many won't ever need to remove a woofer. So for them, this is probably overkill. But there's nothing worse than a spun T-Nut when you're trying to remove a driver, so I think it's worthwhile to do anyway.

Re: skywave's 3Pi subwoofer build [message #74612 is a reply to message #74607] Tue, 27 November 2012 16:30 Go to previous messageGo to previous message
chrisR is currently offline  chrisR
Messages: 36
Registered: May 2009
Baron
Wayne,
Have you tried the hurricane nuts from PE? No prongs, but a sort-of thread on the outside of barrel. They've been easier to deal with for me. Chris
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