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M-21 Giveaway Build Pics

151K views 427 replies 69 participants last post by  pharoah 
#1 · (Edited)
Okay, I was the guy lucky enough to win this amazing 21in driver from Exodus Audio, so I guess I've got to do something with it. This will be my first speaker build ever...no pressure though:yikes:. This post will be a thought starter as I will need lots of input from those of you more experienced types.

Here's my situation and my thoughts. I don't have a ton of room. I don't have a dedicated HT room. My system is in my main living area. Its 14x20 and vaulted ceiling, open floor plan to kitchen, dining room and foyer. There is currently 2 SVS PB-13 Ultras squeezed in there. Every square inch of wall space is taken up by furniture or stereo equipment. Will this new beast be added to the existing 2, replace them, or end up in the HT of my buddy who already has called dibs? We'll have to wait for the finished product to make that determination.

Aesthetics and WAF play an important part of the project as this is the main part of our house. I don't think I want to go sealed because I assume it would take a very beefy amp to get what this thing is capable of in a sealed box. A ported box presents the problem of size. From the little bit of modelling I've done, I think I need to be near 500L to do this driver justice. That has me leaning toward a Sonotube. The sonosub program says I can mount this driver horizontally, but I guess Kevin can answer that more definitively.

In my modelling I'm making the assumption WinISD doesn't care if the box is a cube or a tube, correct me if I'm wrong. i would like to keep this thing down around 6 feet, so I went with a 480L enclosure. In my limited knowledge that seemed to give me the smallest enclosure without sacraficing too much performance. I use my system for music, gaming and movies but most of the high volume is with music. I love loud music with lots of bass. With that in mind I used a 20hz tuning. A single 8in port would require a 24" tube. Those specs get me in that 6ft high range. I'm modelling with 1500W and an active high pass filter at 17hz. I do use a BFD1124p with my Ultras but don't have any eq factored into the following graphs.

Text Font Software Line Screenshot


Text Font Line Design Screenshot


I'm starting from scratch here guys and need your input. These are just my initial ideas based on my limited knowledge, so let me have it. The good, the bad and the ugly.
 
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#162 ·
Ply is a lot lighter than MDF so I wouldn't worry about it. With all the bracing you added and the thickness of the walls you should be just fine.
Besides, your back will thank you for it:clap:
 
#167 ·
I'd bet you got the DIY bug pretty bad by now. - prolly gonna build your own three fronts next, huh?
hold off on finishing if that's the case. You'll get a better match if you do all of them at once.

If not, the I agree with the previous poster, we'd need to see what the existing front end looks like first.
 
#169 · (Edited)
What do you think of this idea. I can get a 1/4" steel plate laser cut by a friend of mine. Paint that gloss black, mount the sub to it, then flush mount it on the box with a 1/4" wood border around it. Then finish the rest of the box natural.
 
#175 ·
I gotta say you went all out on this build and it's turned out awesome so far, exellent job! How many hours do you think you have into it at this point? Can't wait to see it finished, when i started reading the thread and saw the renderings i thought 2 and 3 would have had fiberglass involved in the build but you kicked butt and went all out with wood, I'm amazed!
 
#176 ·
Thank you for the compliments.

My best guess is that I've been at it just over 5 weeks and I've got to be doing about 10 hours a week, so about 50 hours or so I suppose. I spent a lot of hours working on the design as well.

I'm learning as I go and experimenting along the way, so if I did it again it wouldn't take nearly as long.
 
#178 ·
You know Graham you could always do one for that side of the pond.

Its been suggested that I seal the inside of the box with epoxy to help prevent the laminations from cracking. Do any of the woodworkers out there have any pros or cons on that? Or other suggestions.
 
#183 · (Edited)
Maybe you're more charitable than me because I'm not refusing a free Maelstrom 21". My 8" Paradigm was doing me justice until I got a 10" Paradigm. That did me justice until I got an SVS PB13-U. That did me justice until I got a 2nd PB13-U.............you see where this is going. If you're refering to my early comment about not being concerned if this build turned out better than my dual SVS set up, that was a way of justifying doing a sealed build when others wanted me to build a giant ported monster. However, I can see where some would take that the wrong way and I admit it may have come off rude when there are others may not be able to afford either option.

I'm very happy I entered the contest and won the Maelstrom because I would have never undertaken building a sub otherwise. I'm loving doing this project. Its really opened the DIY door for me. Winning this contest for me is way more than the few hundred dollars I saved on the sub.
 
#194 ·
I'm very happy I entered the contest and won the Maelstrom because I would have never undertaken building a sub otherwise. I'm loving doing this project. Its really opened the DIY door for me. Winning this contest for me is way more than the few hundred dollars I saved on the sub.
I'm still glad it went to you - my build would have been a plain old boring box.

If you need an amp and are in the Saskatoon area, I have to put a plug in for a friend of mine - Bill Webster at Night Owl Audio. He has some demo QSC RMX-4050HD's in brand new condition. He's the guy my 1850HD came from. You won't find better service ;)

They're listed here: http://www.nightowlaudio.com/html/equipment/used_equipment/index.cfm
 
#184 ·
I for one am glad it went to a member who is appreciating it, and is going to all the effort of using it and sharing this with everyone here on HTS.

I also like the fact you have taken the chance on a sealed design, and would be interested in how it finally works out, especially in comparison the the SVS's.
 
#185 ·
I'm with you Moonfly, I think corock has one of the most innovative designs I've seen on the HTS. I haven't even started my first DIY project and I already thinking about building one like his. I've got two 15" drivers and a ported Sonotube design in the works but have never heard a sealed sub before. Would I be crazy to build one sealed and one ported and see for myself which I like better?

This may be a very stupid question but would they play well together?

John
 
#187 ·
I dont have a sub right now.:crying: J/K

Anyways your build is truely something amazing. I would have never thought of doing that design. I am just happy that you are documenting your build so well. Thats all I would have asked to whom ever would have won.

WINNING is amazing and the odds are always horrible. Continue documenting this awesome build so I can learn some more carpenter skills.
 
#191 ·
Speaking of sub building....

I'm not going this way anymore, but here are some mock ups of the baffle that I was experimenting with. The Test baffle is cut to exact size so it gives you an idea of what the Maelstrom 21" will look like in my enclosure. You'll notice that in the first picture I routered a groove wider than the sub's basket. That gave me room for a wood donut that I made to cover the mounting surface. The different gaps around the donut is me trying out different router edges. I'm not going to do this now because I'm going to have a black front rather than wood, but I still kind of like it.

Subwoofer Car subwoofer Loudspeaker Audio equipment Sound box


Subwoofer Car subwoofer Loudspeaker Audio equipment Sound box
 
#192 ·
Corock, I'm glad you won (but not as glad as I would have been if I had instead:hissyfit:). Your build has given me ideas for my next build. You've done a great job and I can't wait to see how it turns out.
Mine will also be a sealed build. I've heard, and built, many ported and sealed over the years. I like sealed better. And not everyone wants an elephant in the room.
 
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