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Sealed HS-24 Build

34K views 147 replies 25 participants last post by  DesertDog 
#1 · (Edited)
I wanted to share with everyone the build I finished this weekend. I've been building it the last couple of months. I knew it was going to take a bit for the driver to come in so I took my time and was working mainly on the weekends. The way I finished it also took a couple weeks to do thanks to giving it ample time to dry on each coat.

On Thursday my HS-24 mk III driver was delivered so I was able to finally finish it off. First off it's huge. I knew it was big but until you actually see and try to lift one... My dog in the picture is an 85 pound lab and she looks tiny. Help should be had when moving it. I made the mistake of being over eager and did it by myself which I'm paying for now with a tweaked back.

I did figure out one trick though for getting it and out of the box for drilling the mount holes. The FAQ thread gives the tip of putting zip ties through two of the holes to lift. That wasn't going to work with the weight of it. A zip tie was going to cut a finger off. But I was able to modify off of it. I put two ties through two opposite holes to get a little more strength. Then through each set I put a heavy duty micro-fiber tower that I could grip. It ended up giving me a handle on each side that control lowering it into the box and then picking it back out.



For the cabinet I made it out of 3/4" baltic birch plywood. The hardwood store I shop at was having a big sale so I went with it instead of using MDF. I then add a top and trim to it made from curly maple. I've like the look of figured wood for subs since I first saw pictures of a couple subs from Funk.

I'm not going to bore too much with construction pictures. Since it's sealed it's a rectangular box with fairly standard windowed bracing inside. I can follow up with some pictures of that if anyone wants to see it.



Due to the size of it and that it's going to be in a spot that can be seen I wanted to give it a nice finish. For the body, after a thorough sanding I gave it a heavy dose of a black cherry stain. It was then topped with three coats of satin arm-r-seal urethane.



For the trim and top I wanted to make the curls in the curly maple really pop. So I died it black and then sanded off the dye. This leaves some color in the curls but brings the rest back to natural. I did 4 coats like this to get the curls nice and dark. For the final coat I didn't fully sand it down. I sanded it just enough to give the wood a smokey gray color. I didn't take pictures during these steps and I'm really kicking myself now. I wish I had it documented for the future.

Once the last coat of black was done I added a light layer of purple dye over it. Some extra purple, black, and alcohol (removes dye) was finally used in spots to even out the color and look. This picture is right after the purple was added and it was drying.



All of the curly maple was then finished with 4 coats of a tung oil finish and then a wood wax. I'm really happy with the way the finish turned out on it.




So far the sound is great. I did a basic setup of it last night and ran Audyssey on it. All the demo scenes I played sounded great. The server scene from pulse felt like it was barely stressing it. A couple of the things in my room got stressed out though. :) I then watched RP1 and everything was amazing in it. The big explosion near the end was amazing.

I dialed everything in a bit more today and I'm going to go watch a movie now before bed. I can't wait to hear it some more.
 

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#3 ·
Hey nice job on the finish. I do love curly maple. My dad use to build flintlock rifles out of that and it was beautiful. What did you end up with for a rough inteneral volume? And did you line the walls or fill with polyfill at all? And last what did you use for a amp? I am getting ready to buy one for mine and i am planning to get a fp20000q just not sure if it is overkill.
 
#4 ·
And last what did you use for a amp? I am getting ready to buy one for mine and i am planning to get a fp20000q just not sure if it is overkill.
You are in the wrong forum for overkill. Always get more than you need at every level. Headroom is king!

The clone amps are CHEAP and capable.
 
#7 ·
I wanted to share with everyone the build I finished this weekend.



All of the curly maple was then finished with 4 coats of a tung oil finish and then a wood wax. I'm really happy with the way the finish turned out on it.

Wow, looks brilliant!

Curly Maple was a favorite of mine to finish when I was in woodworking, and with your choice of dye, it almost looks like a highly figured piece of Purpleheart. That’s certainly a one of a kind subwoofer. Bravo!
 
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#9 ·
The best thing about the 24's is their ability to absorb power without bottoming or melting.
Levels that would damage even a 21 and totally toast an 18.

That difference can be the difference between life and death when booming hard.
 
#10 ·
All of the curly maple was then finished with 4 coats of a tung oil finish and then a wood wax. I'm really happy with the way the finish turned out on it.
As others have said, wow, looks like purpleheart! Nice.

I know Overkill is the second Motorhead album. Other than that, is there any other form of it?
 
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#11 ·
Watching a large sub move is mesmerizing. The opening of Edge of Tomorrow gets it moving nicely.


And in slow motion.
 
#12 ·
Watching a large sub move is mesmerizing. The opening of Edge of Tomorrow gets it moving nicely.

That's crazy that you mentioned that movie.. I just watched it last night with my newly finished subs, and it totally caught me by surprise. I never had a clue (with my old subs) the depth and level of bass in the opening sequence. Had to back it up and replay it 3 times before my ears would believe it! :cool:
 
#14 ·
Some updates with new projects that I've been doing.

First I hadn't posted it but at the start of summer I built a equipment rack to match the 24" sub.


Currently I'm working on building a couple VNF boxes that each with have 2 of the 15" DIY soundgroup's group buy driver and 2 SLAPs down firing. Originally I was going to use 8 of the 12" JBLs for it but switched due to size constraints. The boxes for the JBLs were going to be a little wider than the couch. With the 15's I'm going to be able to have them spaced so that one is firing into each of the seating spots and the total size is a couple inches narrow than my couch. I'm going to top the boxes with a curly maple table top that matches the sub and rack. Everything should blend nicely together.

I'm also going to be expanding my BOSS to extend 19" behind my couch. The VNF box are then going to be on it to give extra TR similar to @Nalleh's setup. I'll also be adding another 4 JBLs to my BOSS while I'm at it. The combo of everything should give me a nice upgrade.



For the new boxes I made them out of 13 ply void free baltic birch. It's a bit more expensive than MDF but I like working with it and finishing it a lot more. The base frame was done with dados and glued. The two side were set in a few inches and the connectors are going in the side wall. There's then an end cap that's going to be attached that will hide them.



The front and back attached with glue and pocket hole screws.



The boxes last weekend stained, finished, and with the drivers and SLAPs installed. That's when I realized I messed up. The SLAPs have a mounting depth of 2.25" an xmax of 4". I didn't have enough clearance to the driver's basket. To fix it I added a couple more bezels.



I glued up the two new pieces and had to sand down the finish and stain on that side of the box. Wood glue needs wood fibers. It doesn't hold well with a urethane finish.



Finally glueing the new bezels onto the box. Luckily I have a couple camps :D I set it in an inch from the sides and there's going to be a strip of curly maple added to match the top and to hide the plywood edge. I'll be milling and attaching them tomorrow.

I'm also going to start building the stand for the boxes and two matching speaker stands for my rear surrounds. I have the wood cut for them and just have to assemble all of them. Then lots of sanding.
 

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#126 ·
Some updates with new projects that I've been doing.

First I hadn't posted it but at the start of summer I built a equipment rack to match the 24" sub.


Currently I'm working on building a couple VNF boxes that each with have 2 of the 15" DIY soundgroup's group buy driver and 2 SLAPs down firing. Originally I was going to use 8 of the 12" JBLs for it but switched due to size constraints. The boxes for the JBLs were going to be a little wider than the couch. With the 15's I'm going to be able to have them spaced so that one is firing into each of the seating spots and the total size is a couple inches narrow than my couch. I'm going to top the boxes with a curly maple table top that matches the sub and rack. Everything should blend nicely together.

I'm also going to be expanding my BOSS to extend 19" behind my couch. The VNF box are then going to be on it to give extra TR similar to @Nalleh's setup. I'll also be adding another 4 JBLs to my BOSS while I'm at it. The combo of everything should give me a nice upgrade.



For the new boxes I made them out of 13 ply void free baltic birch. It's a bit more expensive than MDF but I like working with it and finishing it a lot more. The base frame was done with dados and glued. The two side were set in a few inches and the connectors are going in the side wall. There's then an end cap that's going to be attached that will hide them.



The front and back attached with glue and pocket hole screws.



The boxes last weekend stained, finished, and with the drivers and SLAPs installed. That's when I realized I messed up. The SLAPs have a mounting depth of 2.25" an xmax of 4". I didn't have enough clearance to the driver's basket. To fix it I added a couple more bezels.



I glued up the two new pieces and had to sand down the finish and stain on that side of the box. Wood glue needs wood fibers. It doesn't hold well with a urethane finish.



Finally glueing the new bezels onto the box. Luckily I have a couple camps :D I set it in an inch from the sides and there's going to be a strip of curly maple added to match the top and to hide the plywood edge. I'll be milling and attaching them tomorrow.

I'm also going to start building the stand for the boxes and two matching speaker stands for my rear surrounds. I have the wood cut for them and just have to assemble all of them. Then lots of sanding.
You can call us the clamp twins
Plant Wood Tree Gas Art
 
#16 ·
Looks awsome , can’t wait to hear how your impressions:)
 
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#17 · (Edited)
Made a ton of progress last weekend and a little this week. The new bezels for the boxes were finished up and stained with the curly maple border to hid the edge was added. The stand that the boxes are going to sit on was made (hard to see in the picture, the table top is laying on it). The table top for the boxes and the speaker stands I'm making for the side surrounds were cut and glued up.

I started the dye on the top and the stands today. They're drying with the first coat now. This is the slowest part of it for me due to the dye technique I'm doing to get the purple with black curls like my sub. I dye the wood black 3 times with sanding most of the black off after each round. Doing so gets the curls black but keeps the rest of the wood light for the purple dye that's done last. Unfortunately it takes me about a day for each round due to dry time and my neighbors not liking to hear sanders running at night. :)

I should have all the dying done this weekend and the assembly of the stands. The top and bottom aren't attached yet. The glue up for how I'm going to connect them is drying right now. Then next week will be spent finishing everything since once again it's about one coat per day due to dry time of the tung oil that I'm using on the maple.

 

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#18 ·
^^ pic don’t show for me ?
 
#20 ·
Works now, looking great :)
 
#21 ·
New progress update.

I finished up the stands for the rear surrounds. I might make a slight change though and add a couple binding posts to them at the base and run a wire through the tube I already have through the center to make easier to unhook and move around. Pulling the wire from the AVR through the tube on moves (and initial set-up) will be a bit of a pain since two banana plugs that I use won't fit through the tube at the same time.



The curly maple that I got for them came out amazing too. The curls really popped and gives a really nice depth look.



The boxes for the the 15s are done and work great. I was able to power them up for a test last night and everything looked good. Well, almost everything. I thought it sounded a little boomy and then I realized that I forgot to put the poly fill in. So tonight I need to pull off the slaps and stuff the box.



And finally I got a dry fit of the boxes with the stand and top last night before I put the next coat of finish on the top. It's looking good as a whole and was a good test. It showed me that I needed to adjust the stand's bracing that sits between the SLAPs slight. I made that change and finished painting it last night.



I should have these in place over the weekend. I'm probably going to start out with just the subs behind the couch. I don't think I'm going to be able to get the BOSS redone for a couple weekends due to the holidays. I'm also waiting for a new 4 conductor speakon cable. It should be delivered tomorrow. I messed up and thought I had another one.
 

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#22 ·
Looks great :)

BUT: PR subs are NOT supposed to have stuffing in them !
 
#23 ·
Really? Why not when you do other subs? I was looking to tame a little bit of the boominess that I heard last night. Thinking about it, I might try laying one down on the carpet and test again. when I had it running last night it was standing on end on the tile floor. It's possible the boom was from the the small cavity on the end with the tile.
 
#24 ·
Stuffing the box slows down the transfer of energy from the active driver to the passive driver. It also says so in the manual ;)

If they sound boomy, that can be fixed with EQ ;) What LPF are you using ?
 
#26 ·
@Nalleh I'm just about up and running minus the BOSS expansion. The boxes are in place and a quick dry run with just some music sounded good. I'm going to start getting them integrated with everything else tomorrow. A couple questions though. What did yours end up being tuned to? I need to double check things tomorrow when I'm awake but it seems like I ended up a little higher than I was expecting. I might add some more mass which I know you didn't do. So I'm curious as to what frequency you ended up at since you've been happy.

This is my first time doing a PR build. Is a high pass filter supposed to be added like with a ported box? I thought I read that one was (and I added one to be safe) but I'm not having much google luck right now getting an answer.
 
#27 · (Edited)
Ooops, i totally forgot to answer here, sorry about that.

Yes, i just used my SLAPS as is, so including the 255gram mass, and the tune ended up ~ 22hz, i think.

I don’t use a HPF, on the contrary i use a lowshelf, LOL. The stupid capacity on the SLAPS, and relationship between it and the JBL’s seem to make a HPF unnessesary. At least in my case, so far.

If they are like mine, you need to EQ them down in the upper octaves, probably from 40hz and up. And a LOT. I have probably ~20-30dB negative high shelfs on mine + a 60hz LPF at 12dB.
So yeah, un-EQ’ed and too high LPF(above 80hz) they can be boomy, alright ;)
 
#29 ·
Yes, see how it looks in REW, and then go from there.

I only have a 5dB LS on mine to make them reasonably flat all the way down, but I have a lot of EQ above 40hz to tame them ;)

When you are done EQ’ing, just play some familiar content while upping the level on them, they’ll let you know when you push too far :)

But are you just using them as VNF so far, or are they ON the BOSS plattform, for BOSS duty as well ?
 
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#31 ·
Ok, cool. Since I'm using the 15s I'm hoping I don't have to tame too much. We'll see what REW brings. I'm hoping to start measuring tonight, if not I'll be able to over the weekend.

Just VNF right now. I need to build the new BOSS first. I drew up the design for it last night and I'm going to go get the lumber tomorrow. I was going to go tonight but I forgot to register my truck and have to do it first tomorrow. Not going to get a stupid ticket.

I'm going to beef it up a bit when I do it. I'm going to run 2x6 and 2x4 front to back in instead of the 1x6 and 1x4 like the current one. It should give me some more stiffness and help with the cantilevered part. @Magly post about having his free air has me intrigued too. I don't think I can do that without tipping. I'm pretty sure the VNF boxes weigh a hair too much. I'm going to play with it though. It extends about 20" behind my couch. So I'm thinking of playing with putting the isos halfway and finding the point that will cause it to not tip. I'm wondering if I hybrid it like that if I'll get a little extra out of it from having them all the way back. I just wished it was easier to move them around with the size of my riser.
 
#32 · (Edited)
Got it :)


Yeah, beefing up the frame underneath will help since you are adding cantilever. My 2x4 frame ended up incredible stiff, more so than i thought it would, so go for it ;)

Yes, you and me have a little heavier rear load than @Magly has, LOL. But sure, placing the iso’s more forward is one way of tuning it towards free air, without it tipping. Don’t now if you’ve seen my latest idea of using innertubes under the rear to simulate kind of the same thing, but it seems to work very well :)
 
#33 ·
Yeah, I saw the innertubes that you did. It looked interesting. I haven't really considered doing it yet. Maybe I'll take a look after doing this phase. I'm not sure how practical if will be for me though due to the size of my platform. The new one is going to be about 6.25 m^2 (2.5x2.5m). So I have a few concerns with doing it. Mainly:
- Getting the tubes sized and placed correctly for the size so that it's stable.
- Getting the underside smooth enough so that the tubes don't get punctured. I've been using rough lumber underneath and not standing at since once it's set up it is never scene again.
- Setting up some way to auto inflate and deflate with the size.

So, we'll see. After I get the BOSSac 2.0 set up I need to take a little break from building physical stuff to finish up BEQ Browser. It's been dragging on way too long now and I need to get at least the initial version out. It's needed for a couple different fronts.
 
#34 ·
^^^ will await your impressions ;)
 
#35 ·
Well, I almost have all my subs dialed in. Still deciding if I want to tame that peak at 14 hz. Thinking of keeping it in to keep the little bit extra boost in the ULF. Now to start playing with it.
 

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#36 ·
Not to shabby ;)

Remind me again: what was the rest your the sub setup?

Could you reconfigure graph to show 5dB increments?

Could you graph just the VNF’s?
 
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#37 · (Edited)
The 4 15" for VNF, the 24", and I brought my Monolith 12" back into the room and integrated it with the others. It was nice, I was able to place it to fix a null I had in the mid-30s and another in the mid-50s when using just the 24" and the VNF.

Sorry about the increments. I had it at 5 db on screen and didn't realize it exported the screen shot at 10. I've redone it and included the VNFs. The VNFs are them "raw" with no filters turned on.

After playing a few clips tonight I might need to redo the final curve to tame the 14hz peak a little and to turn down the slight house curve I added. It mixed with my BOSS felt slightly out of balance with the rest of the sound stage. I need to do some more listening though when I get home from work tomorrow before making any changes.
 

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#38 · (Edited)
^^^ Awsome job integrating it all ;) Mixing two different ported ones with one sealed isn’t easy ;)

Yup there is that ~40hz peak! I have it on my VNF’s too. I have a messy room, so i needed a lot of EQ on all of mine.

Just my curiousity, but could you also graph the Monolith and 24" ?

Tuning for FR and tuning for TR is a bit different, and introducing VNF’s kind of mixes the two.

IMO you need to start with the farfields, get the FR inline and EQ’ed best as possible, then do the NF(24" in your case) and get it integrated with farfields. Then on to VNF’s, EQ’ed and integrated with the rest.

Of these 3 subs, the VNF’s is most likely contributing most to TR, so your TR devices then need to be tuned to your VNF’s. So that may be why you feel your BOSS is out of balance, because earlier it was making TR all by itself, but now the VNF’s are contributing to TR. And those two need to be in sync.

Also, the dip at 10hz shouldn’t come from your VNF’s, that is way below tuning for them.
 
#39 ·
^^^^^Thanks! I can post the other graphs when I get home. I have them on my MBP that I keep in room for BEQ. The Monolith I ended up running in it's sealed config with both ports plugged. It had looked best with one plugged when running on it's own, but I got the best combined response with both plugged.

My room isn't the best either. It's rectangle but one of the short walls is mostly open the the foyer with only a 4.5' wall for one end of it. It also has a sloped ceiling which made installing the Atmos speakers fun. It'll be nice when I get a new place that I can setup correctly.

What you described with doing the VNF last is the order I went. I didn't EQ them separately though. I got everything time aligned and then EQed at one. Similar to the .

I ran out of time last night to retune the BOSS. I'm going to mess with that some tonight. I might just turn it down a little for now since I'm hoping to be able to work on the new riser this weekend.
 
#70 ·
^^^^^Thanks! I can post the other graphs when I get home. I have them on my MBP that I keep in room for BEQ. The Monolith I ended up running in it's sealed config with both ports plugged. It had looked best with one plugged when running on it's own, but I got the best combined response with both plugged.

My room isn't the best either. It's rectangle but one of the short walls is mostly open the the foyer with only a 4.5' wall for one end of it. It also has a sloped ceiling which made installing the Atmos speakers fun. It'll be nice when I get a new place that I can setup correctly.

What you described with doing the VNF last is the order I went. I didn't EQ them separately though. I got everything time aligned and then EQed at one. Similar to the Home Theater Gurus video..

I ran out of time last night to retune the BOSS. I'm going to mess with that some tonight. I might just turn it down a little for now since I'm hoping to be able to work on the new riser this weekend.
So the Home Theater Gurus approach I'm pretty sure you get a biquad file to import to minidsp. I saw him importing this to the inputs where we put our BEQ settings. So are you just importing the biquads to each output channel individually.:confused: I've never used the Biquads so am I right that you really can't tweek or change your minidsp output settings when using the Biquad file? (I'm going absolutely crazy right now integrated my new PB4000 sub with another sub and has just been a vortex of time in minidsp.:rolleyes:)
 
#40 ·
^^ Got it ;)
 
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