Lambda/Dayton PR sub: *PICS* (1 Viewer)

[Jack Gilvey]

I laid out the details of this sub in
http://www.hometheaterforum.com/htforum/showthread.php?s=&threadid=41898

(Edited pictures to new server, 3/30.)

 

[Dan Hine]

Wow! I love it. And with the stool being white, the sub almost looks like it is floating. I think the laminate looks great. That is what I tried to do with paint. I guess I know now what I'll use next time. Laminating the PR's is a nice touch. Does it have any adverse affects though?
Anyhow, you've just inspired me to do another one. Thanks a lot!
Dan Hine

 

[Brian J Dupuis]

Holy...
Wow, Jack, that's a really nice looking sub you have there. I really like the laminate, a whole lot. Looks like you did a great job with it. And the laminate on the PR?! Very sweet. You're doing your level best to get me to start on my mains and center, aren't you?
That's a great story about Pete's generosity, too. I'm currently working on my "Beginner's DIY Subwoofer Project" page, and just wrote the paragraph on the "whole segment of the DIY community that provides valuable information, advice, and support essentially for free." Pete's helpfulness truly defines that spirit. Kudos, Pete!

 

[Kyle Richardson]

Very, Very nice looking sub Jack! The laminate looks very nice and I'll bet it was even easier to apply than you thought (at least thats what I thought when I did my Kit 281's)

Kyle Richardson

Acoustic Visions

 

[Jack Gilvey]

Thanks very much, guys!
Dan, I don't think applying the laminate to these particular PR's has any effect beyond slightly increasing the Mms. The laminated area is only a painted black MDF disc in its original form, and I didn't overlap the surround material at all, I stayed just inside it. FYI, I used 3M 77 spray adhesive applied to the piece of laminate only.
Brian, I'll bet you'll have your mains and center completed before I do. I look forward to your writeup.
Kyle, I guess it was easier than I expected, but I really took my time, and the right tools are essential. I used 3M 90 spray adhesive to apply it, and my Dewalt 621 with a 1/2" flush-trim bit to cut it to size. If doing it again, I think I'll pick up a dedicated laminate trimmer, though. There were parts I screwed up, as I learned the technique on this thing, but I'm pretty happy with it.

 

[Wes Nance]

Jack,

What a cool looking sub! I'm starting today on mine- very excited, and a bit nervous, as it's my first DIY project. I figure I'll be relaxed about the whole thing and be prepared to learn as I go!

I'm planning to use quarter cut maple veneer on the sides and top (one piece bent around the roundovers), and over the PR's (like yours) and flat cut maple on the front and back.

My wife and I have been trying to decide whether to have the veneered PR's match the cabinet color (natural, or very light stain) or to stain them black to match the PR frame and surround- what do you think?

I'll start a threat with pics when I start-

Any more listening impressions on yours?

Wes

 

[Ryan Schnacke]

That's a beautiful sub, Jack. The gloss laminate looks very nice.

I appreciate your help with my brother-in-law's sub. We went with 1 cu ft stuffed as you suggested. Plain MDF enclosure, no finish since it just went in his trunk. We tested it in my 6000+ cu ft living room and it was unbelievable how much bass can come from such a small box. It didn't nearly have the extension of my 25-31 but it could really shake the windows. That was running off one channel (coils in parallel) of a cheap 70WPC Pioneer receiver.

I'm closing in on a design for the other 12" DVC (this one's mine!). 105L tuned to 20Hz looks good. I think that's a 4" diameter x 20" long port - I'm still a bit green at using Unibox. This'll be powered by the 70W receiver mentioned above, so I don't think I'll run into port chuffing with only 140W on tap. But Unibox seems to think that 4" may not be quite big enough.

 

[Wes Nance]

oops, didn't mean to scare anyone!

I'll start a *thread*. . .

 

[Pete Mazz]

Jeez, I've been called S**t-for-brains before, but never "copious brains"!
Jack, I was glad to help out. You've given a lot of people help (myself included) on the Forums, so I thought I'd return the favor.
I'm still embarrassed about the matte black. I don't ever remember it coming in with a peel coat. Good thing I didn't use it on a project and then find out!
I'm still curious as to what's "not perfect". It looks like a great job to me!
Pete

 

[ThomasW]

Jack
Pretty impressive looking for a laminating newbie. Very nice job with the facade for the PR's

 

[Jon Hancock]

Very nice looking, Jack! If the gloss laminate looks as nice in real life as your picks, I'm sure you're super pleased! It looks very close to a piano gloss finish- how do you think it compares? What brand of laminate is it?
And, how does it sound? How did using a lot of stuffing (as opposed to lining) affect the response curves? Do you have any impedance plots?
Last, should we expect something similar for the BP1803?
Best regards and congratulations on the nice work,
Jon

 

[Jeff Rosz]

hello jack,

killer looking sub. my sub will be wearing laminate soon and i have a couple questions for you. you said you used 3m77 and 90 spray adhesives. whats the difference between the two? and why did you use the 2 different sprays? did the pr require the use of a different glue? thanks, and again nice job.

 

[Scott Simonian]

Wow Jack! They just keep getting better and better.
Let us know if it rocks the place.

 

[Jack Gilvey]

Thanks again guys for all the nice words. I'm truly flattered by the people contributing.

Wow Jack! They just keep getting better and better.
Let us know if it rocks the place.

Thanks, Scott. Indeed, if nothing else, it rocks the place.

 

[Vince Bray]

Very nice work, Jack! I want to put in another vote for a 1803 / PR design. Can the 1803 be used downfiring? If so, maybe a cube with a downfiring 1803 and PR18 on all four sides, so it would be balanced. Hmmm...

Vince

 

[Mike_Ped]

HOLY GOD that is a nice sub!!

P.S. What's laminate exactly? How would one do that?

 

[Jack Gilvey]

Thanks, Ryan, glad I could help with that sub. I'll bet it's amazing in a car if it performs as well as it does in a room.

105L/20Hz looks very nice to me for the DVC, also, I think you'll be OK with that port as long as you use a dual-flared one, they really cut down on noise.

HOLY GOD that is a nice sub!!

P.S. What's laminate exactly? How would one do that?

Thank you, Mike. Laminate is plasic sheet material that comes in numerous colors, patterns, and textures. Formica and Wilsonart are two brand names of the stuff. Typically it's used for countertops, etc., but it has other grades and uses.

Here's a basic outline of what I did:

First of all, it did take me a long time since it was my first experience with laminate or veneer-type work and since I had to not only flush trim the three cutouts but punch and drill all the bolt-holes again plus do the circles on the PR's. I guess 7-8 hours altogether, and three pots of coffee. I really take my time with this stuff, though, since I hate for things to go wrong.

I cut each piece to about 18" square so I'd have enough margin for error when applying each one. I tried my box-cutter, but picked up an actual laminate cutter ($5 at HD) which made the job much easier. Basically just scoring with a straight-edge then snapping it off.

I sprayed 3M High-Strength 90 adhesive on both the box side and the laminate and let tack-up for 5 min or so. The piece was then carefully applied to the side smoothing from one side to the other. I'm glad I left myself that much overhang, since there's no going back once you start to apply it (I needed it). I used a high-pressure J-roller like a madman at that point, especially on the edges. I used a wood block at the very corners, though, since accidentaly going over the edge tends to break the laminate with the break actually scalloping into the workpiece and not just cracking nicely on the edge (don't ask).

I then trimmed with my router and a 1/2" flush-trim bit and cleaned up with mineral spirits.

The PR's where done by cutting a plywood circle in the diameter I needed, fastening the "scrap" laminate piece from the PR cutout to the plywood with some double-sided carpet tape and just flush-trimming the piece. I used 3M77 spray adhesive to lam. the PR's.

Finally I filed the edges with a laminate file just to take the sharp edge off.

 

[Jack Gilvey]

Fwiw, I just confirmed Fb using the rather primitive method of running one of the 200-20Hz descending frequency sweeps from Avia, A-B repeating the 30Hz-20Hz part, and feeling the driver for the point of minimum excursion. As near I as can tell (I think I got it, the sweep moves just slow enough), this point occurred between 23-24 Hz with a quick rise below that, which is what Unibox predicted.

A hand is technically a "digital" meter, right?

 

[Wes Nance]

Jack,

Very cool- I bought the Stryke bass test cd so I could have more time to react to stuff than Avia gives you. . .

I wanted to ask your opinion (again) on my project- I've basically got an 85l box (before drivers, bracing, etc.) and the Stryke SAE 1204, with 2 15" Lambda PR's. The PR's are currently weighted to 1050 each. I was going to get them to 1400g each, like yours, but the different curves in Unibox are pretty interesting. I'm wondering if, based on the results of your sub, you have a recommendation? John at Stryke thinks the sub will be great at 1050, just a bit different than 1400.

Also, the PE 250w amp I bought doesn't have any bass boost as the default setup, which means also that there is no rumble filter enabled. Looking at driver excursion plots in Unibox, I'm concerned about overexcursion below 20hz. I could enable 1 db of boost in the 20-24hz range, which would set the rumble filter to start around 20hz, I think. Do you think this is a good idea?

Thanks again- I've got all the sides cut, and one 15" driver cutout/rabbit left to do. I hope things are cut close enough to perfect- using just my circular saw and home made sawboard left a bit too much play in things. . .

Congrats again on your awesome looking and sounding sub!

Wes

 

[Seungsoo Hwang]

sweet lookin sub there jack.