1.5 cu. ft. sealed build w/Scan-Speak Revelator Subwoofer - 32W/4878T

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cameraman

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I am building a pair of 1.5 cubic foot sealed enclosures for Scan-Speak Revelator 13" Subwoofer - 32W/4878T drivers. They will be used with a pair of Dynaudio Contour 20"s and bass managed by an Anthem STR Preamp I ordered. This will be prioritized for 2-channel music although I will take advantage of Home Theater Bypass.

I'll use my normal Baltic Birch/MDF composite laminated with glue for the front and back, 3/4 inch MDF for the sides, at least 1 BB brace on the inside with a BB tie in to the back, finish with 1/4 inch x 5 or 6 inch oak boards for the sides and true 1 inch milled oak boards for the front fascia, likely 4 inch wide glued together. I'll use Dura Seal Jacobean stain, almost as dark as ebony, to match my wife’s hardwood floors.

The first cabinet is ready for stain as soon as it arrives and I bought the lumber except for the milled 1 inch oak boards to start the second cabinet.

The oak adds some weight and size to the box but makes the enclosure more rigid and seals all the seams. I add the oak primarily for cosmetics though. Final outside dimensions; 15 1/2 inch Wide, 16 1/2 inch tall, 17 1/4 inch deep. I haven't weighed it yet but it will be heavy.





cameraman

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duplicate

opnly bafld

Nice  :thumb:

WGH

Looks like an excellent combination. What is the sub amp?


cameraman

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Looks like an excellent combination. What is the sub amp?

I just bought a used QSC PLD4.2 amp with less than 9 minutes on it. I am still deciding if I want to use it for the subs but will likely give it a try. Coincidentally It came from a neighbor's mega church. I just don't know much about it and I don't need or want any DSP from it. Wish it could disable any A/D treatment but it probably won't matter for subs.

https://www.qsc.com/live-sound/products/power-amplifiers/pld-series/pld42/

JohnR

Very nice  :thumb: :thumb: Presumably that is the T00 version (not T01) - https://www.scan-speak.dk/product/32w-4878t00/ ?

Nice looking amp too. Gives you room to add more subs later :green:

cameraman

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Thanks @JohnR, and yes, it is the sub-woofer version, not the woofer version.

I don't know if I have room for any more, below is some but not all I have built.



WGH

Thanks @JohnR, and yes, it is the sub-woofer version, not the woofer version.

Is this your first sub build using the Scan-Speak Revelator 13" Subwoofer - 32W/4878T or are you moving up in both quality and price?
The price on Madisound is $566.50, why did you pick this driver instead of something like say, the $229 12" server driver for a sealed cabinet at GR Research or something else?

I'm certainly not opposed to high priced subwoofer drivers, the replacement driver for my REL Gibraltar G2 sub cost me $800 but it's a nice one.

cameraman

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Is this your first sub build using the Scan-Speak Revelator 13" Subwoofer - 32W/4878T or are you moving up in both quality and price?
The price on Madisound is $566.50, why did you pick this driver instead of something like say, the $229 12" server driver for a sealed cabinet at GR Research or something else?

I'm certainly not opposed to high priced subwoofer drivers, the replacement driver for my REL Gibraltar G2 sub cost me $800 but it's a nice one.

I at one time had a very nice 2-channel system in my family room, coincidently with a DIY kit from North Creek Music, an MTM design including a Center using all Scan-Speak Revelator drivers. The Vision Signature. They are in the collage above.

https://web.archive.org/web/20030412105145/http://www.northcreekmusic.com/Vision/VisionInfo.htm

My wife had me move them out and I put in Infinity Cascades, decor friendly but not the sound I was used to.

With 2-channel the priority and some decent monitors in the Dynaudio Contour 20's I wanted quality sub drivers that would work well for music in a small enclosure and the 32W were universally praised. The Anthem STR preamp is supposed to have very good bass management.

I built an enclosure with the Scan-Speak 28W/4878T Revelator 11" Subwoofer for our X6 that has worked very well and used the ScanSpeak Revelator 23W/4557T-02 with the matching passive radiator in a 1 cubic foot enclosure that sounds fantastic as well. I also built a 2 cubic foot enclosure with an Aurasound NS12-794-4A that I use in another room. It is excellent as well but the enclosure is a bit big and the natural oak finish doesn't work in the family room anymore.

So no, I was pretty set on the Revelator's, Im obviously a fan and with all the investment I am putting in to the system, didn't let the cost of the drivers influence my decision.

I also use an 18" LMS 5400 and a pair of 15" LMS-R's in my Basement Theater so can't say I've ever skimped on driver budgets.

Stain won't arrive untill this weekend at the earliest, a full size of the enclosure while I wait.




cameraman

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I stained the cabinets and they match our hardwood floors perfectly. There are a few blotches that bother me though. The end edge grain on the fascia is always a challenge as it tends to take the stain much easier. I wish I wasn't a perfectionist but I think I will sand them down and re-apply the stain. I think I just needed to do a more thorough sanding job. Whats another day or two as long as this is taking me.




WGH

Yea, that's pretty ugly. I've been there.

Hard to tell if the blotches are deep swirls or scratches from a belt sander. Since the boxes are solid wood you can really attack them. The stain will clog the sandpaper so start with some cheap stuff. Stay with the random orbit sander for all the sanding. You will have to start with 80 grit, at least the scratches are easy to see now, probably will take 10 disks per cabinet for initial cleanup to bare wood. Then move up to 120 grit, 150, 220, 320. You can go finer if you like, those round overs can take forever to get perfect. The 220 grit will still leave small swirls when staining so I always have to go finer.

Dewalt random orbit sanders have a 3/32 orbit, nice for finishing. The $89 Mikita has a 1/8" orbit, bigger orbits leave bigger swirls.

I use a Dynabrade Spirit 59020 12,000 RPM, 3/16"orbit for rough sanding and stain removal and switch to a Dynabrade 59035 12,000 RPM, 3/32" orbit for 150 grit and finer. Not all air compressors can handle 14 SCFM at 90 psi for hours at a time, generally you need a good 2-stage 5hp compressor.

russellberg

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I am doing a similar application of thicker hardwood over MDF on a set of speakers. I have some beautiful quilted maple and I think it will look amazing. One question: did you have any issues cutting the hole for your driver?  I am worried that my router bit may not reach through 1½” of wood and MDF.

WGH

I am worried that my router bit may not reach through 1½” of wood and MDF.

Shouldn't the inside edge of the hole have a round over? Can't do that after it is assembled.

If you don't care about the round over then you can route the first .5" or .75" deep the usual way then use a top bearing straight pattern bit to finish up.
https://www.grizzly.com/products/Grizzly-3-4-Straight-Pattern-Router-Bit-1-2-Shank/C3702Z



Cut out the MDF hole about 1/4" too small with a saber saw and use the router bit to clean up to final size.

cameraman

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Thanks, I have an old Porter cable 1/2 sheet finish sander that has held up well. I'll leave the belt sander alone. I've never worked with Duraseal Quick Coat before but that is what I need to match my wife's floor stain.

Yea, that's pretty ugly. I've been there.

Hard to tell if the blotches are deep swirls or scratches from a belt sander. Since the boxes are solid wood you can really attack them. The stain will clog the sandpaper so start with some cheap stuff. Stay with the random orbit sander for all the sanding. You will have to start with 80 grit, at least the scratches are easy to see now, probably will take 10 disks per cabinet for initial cleanup to bare wood. Then move up to 120 grit, 150, 220, 320. You can go finer if you like, those round overs can take forever to get perfect. The 220 grit will still leave small swirls when staining so I always have to go finer.

Dewalt random orbit sanders have a 3/32 orbit, nice for finishing. The $89 Mikita has a 1/8" orbit, bigger orbits leave bigger swirls.

I use a Dynabrade Spirit 59020 12,000 RPM, 3/16"orbit for rough sanding and stain removal and switch to a Dynabrade 59035 12,000 RPM, 3/32" orbit for 150 grit and finer. Not all air compressors can handle 14 SCFM at 90 psi for hours at a time, generally you need a good 2-stage 5hp compressor.

cameraman

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  • Posts: 46
I used to drill the hole for the jig pin all the way through the two laminated 3/4 inch MDF BB pieces and route from both sides but could never drill the hole strait enough by hand and there would be a noticeable offset. Not an issue since its not seen. I ended up getting a 1 1/2 inch Single Flute Strait bit so no issue any more going all the way through.

I'm not sure it matters for sub-woofers but I also like to use a 1/4 inch round over on the inside edge of the BB before assembly/gluing.

I am doing a similar application of thicker hardwood over MDF on a set of speakers. I have some beautiful quilted maple and I think it will look amazing. One question: did you have any issues cutting the hole for your driver?  I am worried that my router bit may not reach through 1½” of wood and MDF.

WGH

Thanks, I have an old Porter cable 1/2 sheet finish sander that has held up well.

I haven't used my 1/2 sheet sander in 20 years since random orbit sanders were invented. I think you would get better results with the Dewalt 5" random orbit sander, faster too.

cameraman

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I haven't used my 1/2 sheet sander in 20 years since random orbit sanders were invented. I think you would get better results with the Dewalt 5" random orbit sander, faster too.


Aren't they orbit sanders as well?

WGH

Random orbit sanders are orbital with a trick up it's sleeve, an eccentric pattern that leave smaller swirls.

The 1/2 sheet sander is much slower at removing wood which is probably why your cabinets have scratches and blotches, you didn't spend enough time sanding. Usually prepping a surface takes hours and hours, finishing takes just as long or longer than the actual construction.

The Rockwell 505 was the gold standard sander in it's day but all my woodworking buddies have switched to the 5" circular random orbit sanders, same as me. The 505 still gets the job done, but in twice the time.

Here is a good explanation of the two types of sanders:
https://www.youtube.com/watch?v=a8iFJL0wVXU

cameraman

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  • Posts: 46
I'll pick up a 5" random orbital sander and give it a try. Thanks.

WGH

I'll pick up a 5" random orbital sander and give it a try. Thanks.

Make it a Dewalt  :thumb: