Dual sealed Maelstrom's up and going

Discussion in 'Archived Threads 2001-2004' started by Carl_Berg, Feb 11, 2002.

  1. Carl_Berg

    Carl_Berg Auditioning

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    Well have been a long time lurker but first time poster.

    I have built 2 separate Maelstrom subs - each a clone of the other.

    Exterior dimensions are 22" wide and deep and 23.5 inches tall - I did not want a true cube. Each is constructed using one sheet of 4x8 appleply (13 layer maple faced, void free) and is stuffed with 5 lbs polyfill. There is a T brace and the driver side is 1.5 inches thick.

    First off - I purchased a Kregg pockethole jig just for this project and this thing rocks... Makes assembly an easy erector set - with only 2 24 inch bar clamps. I also used Gorrila glue - and this stuff is also really great to use and get off of everything you don't want it on. (except your skin).

    A little background. I made these for bass enhance use for my lex - not LFE. That will be another project for another time. However for the time being they trounce my HSU TN1220 w/500 watt amp (now for sale)so they will be used and moved around for multiple uses.

    I was also surprised at output as well as airmoving capability. These now provide the "feel" of being there. They most certainly excite a lot of air. Do let me tell you that although fairly small in the grand scheme of DIY subs, however my wife is quick to point out - those are 2 big boxes. (heavy too - about 100lbs finished each).

    The weight was also a reason I went with 2 separate boxes. I can stack them and make a pretty cool looking column, or have one on each side for bass enhance.

    Anyhow - I am stoked. This wasn't a real quick build and I still have 2 coats of Poly to put on (maybe 3). Powering these right now is 2 channels from a Cinepro 3k6 mkIII but I think I will probably use my parasound 2003a that is just sitting not doing anything. 300 watts should be plenty.

    Just wanted to add myself to the growing list of Happy Sub DIY'ers.

    Now, what to do for that 120db at seats capable monster LFE sub... (anyone with ideas and have it be smaller than these cubes?).

    Oh yes, there was a post a couple days ago where people where saying they just don't get the Maelstrom as all that great a buy? Well for me here is the answer (first off I did get them on pre buy so they were cheaper).

    Incredible efficiency, fairly small sealed boxes can get pretty darn loud with very little power. Low Q around .6, and deep extension for a sealed sub. (I played the Stryke Bass zone cd and although not audible 10,12.5,15,17.5, and 20HZ all shake the living daylights out of my house. Even turning 10hz sine waves was a little distressing. Makes you feel tense and you can count every rattle to the beat.

    Anyhow I'm happy.

    Total cost tally, for 1

    binding posts 8 bucks a pair parts express

    Kregg screws for pockethole jig 4 bucks

    stain 6 bucks

    polyurethane 12 bucks

    1 sheet 3/4 appleply 85 bucks

    Maelstrom (preorder 225)

    fiber fill 5lbs 14 bucks

    sanding pads 8 bucks

    Total about 365 bucks per.(now that is bang for the buck)

    Now I had all the other tools, router, tablesaw, bits, etc... not factored in.

    Thanks

    Carl
     
  2. Carl_Berg

    Carl_Berg Auditioning

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    Hi Jack,

    I happen to live in the NW and I believe the biggest supplier of Appleply is States industries in Eugene Oregon.

    Appleply is hard to find but can even be had in 1.25 inch thicknesses, which is also 21 ply. Although finding someone with that 1.25 or even 1 inch is really tough - I looked for a long time. Baltic Birch or Appleply is structurally very similar just that you get maple face with appleply. Oh yes, minimum order I have found is 30 sheets if you want the larger thicknesses of Appleply. Now that is a lot of subs...

    And to those who don't know there is no apple wood in appleply - where it got it's name - I have no clue.

    However, it is well worth looking for. It has furniture grade exterior maple facing, and routes to a very fine quality. The edges look good and no veneer work.

    Make your box and your ready to go - and looks good to boot. This was really the kicker for me in that I did not want to go to the trouble of veneer work. My wife was pleased enough that she now has asked me when I will be doing a built in bookshelf...

    Anyway - I am now stuck at work wishing I was cranking my system up loud...

    C.
     
  3. Jack Gilvey

    Jack Gilvey Producer

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  4. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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  5. Jack Gilvey

    Jack Gilvey Producer

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  6. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    Good point Jack. I have a big room to fill. Longest wall is 30ft meaning I get zero room gain until below 20Hz. So I also tend to think in terms of the sub doing all the work.
     
  7. AjayM

    AjayM Screenwriter

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    I'll stick with my big sealed boxes. I was actually shocked to see how well my 170l sealed Tempest performed when I ran some tones through it to tune the BFD, I'm getting solid flat response down to 18Hz (and that was before I started to EQ it, I had to EQ it down at 20Hz because of around a 3db peak).

    Of course I can't hit the crazy SPL numbers some of you guys can hit, but it's more than loud enough for me.

    Andrew
     
  8. Carl_Berg

    Carl_Berg Auditioning

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    Well after typing a reply and having it suddenly disappear (I hate that) here I go again.
    Jack the Baltic Birch is a great looking incredibly solid product - biggest drawback I see is it is only available in 5x5 sheets. (pain to transport) and in my case would have created a lot of waste. 4x8 sheet works great for the this maelstrom project - and as I see it is another benefit to appleply.
    I hope to do a follow up with measurements from my Rat shack meter and running tones from the Stryke test CD I have.
    Are Warble or Sine waves a better tone to use for measurements?? And would 1M or listening position be of more interest?
    I will also do some distress testing and peaks. Run a tone, crank the volume until it starts to sound strained, or scares me [​IMG]. (oh my wife is going to hate me...) and see how loud it gets.
    Ryan, I understand some of your statements you made on the value of Maelstrom. But for a fairly small enclosure (22inch cube - mine has legs and is downfiring so appears bigger) you get 3L of dispacement and very high efficiency. I would bet that at 96db efficiency you could probably make this thing get pretty loud driven directly from a decent preamps output.
    Not to mention - I did look at the blueprint option. About the same dollars per driver but, many of the blueprints even state - not a great alternative for sealed. They also require HUGE amplifier power - so I think you were looking and focusing on just driver cost. Also a BFD is a requiremnet, not a niceity. Look at the total solution and the Maelstrom is pretty cheap. 375 complete minus amp. A adire AVA250 would drive this to pretty insane levels around 115db in room at 1m at 20hz (this is anticipated and projected but I will quickly state I am a LSPcad newbie and could very well have screwed the numbers up.(this is for a single not my stacked pair). Not only that group delay is peaks at 11msec and this even includes the crossover circuit. (read very low).
    However, for an LFE sub, I totally agree, a ported larger sub with a tempest would thump more down low than this option - just with greater group delay.
    In any event - Dan Wiggins has assured me that even at 14-15 feet away I should be in excess of 105 db from 17 hz up. Tonight I'll know for sure.
    None too shabby for sealed subs.
    Again this is not the end all of subs. (my next attempt will be closer and for lfe only) but for music bass enhance use on my lex, this is fun stuff.
    C.
    Oh Yes, and thanks to many of you here who have shared their experiences, and knowledge. I wouldn't have done this without seeing the great success many of you have had.
     
  9. Kyle Richardson

    Kyle Richardson Screenwriter

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    They sound like they are very nice subs!

    Hopefully, I will have my 283 liter vented Maelstrom up and running within about a week or so.

    Kyle Richardson

    Acoustic Visions
     
  10. Carl_Berg

    Carl_Berg Auditioning

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    Jack,
    The Pocket hole jig I bought is the K-2000 pro-pack. You mount the clamp and jig holder onto a scrap piece of plywood and it makes making the pocket holes really quick.
    Here is a link with a pic, although I was able to find it local for about 120 bucks.
    http://shop.store.yahoo.com/squaredrive/ktc-2001.html
    I planned out where I needed all pocketholes to be than did all holes in one streamlined assembly line. The jig comes with everything including 1.25 inch screws. (these are the right size for 3/4 inch material - I would assume that 1 inch ply would need 1.5 inch screws.) If you have a good woodcrafting store nearby they would probably carry this jig. Also - just like routing ensuring the depth of the pocket hole is right is critical so do some test pieces with scrap. And if you are going to do a roundover after (I did all roundovers first)- ensure you will not hit a screw tip with your router bit - again depth is critical of the pocket hole.
    The way I made my subs was that both front and back of the sub the width was 20.5 inches, and that both sides of the sub are 22 inches wide. With the material being 3/4 inch ply that makes a 22 inch cube. I made 3 pocket holes on each side of the front and back 20.5x22 pieces, and 2 on the top and bottom. Both sides only had a total of 4 pocket holes, 2 on top and 2 on bottom.
    This makes assembly real easy - even if you are short on clamps - I did both subs with a total of 2 24 inch bar clamps and 2 12 inch (although having 4 24 inch clamps would have been handy in that I was building 2 subs).
    Prior to doing any glue, mount all screws into recessed holes and hand tighten (with fingers) so that the points of the screws do not poke through the to be glued material.Wet one side, spread glue the other, 2 clamp the 90 degree corner, tighten screws, unclamp and move on. You can do the entire sub not waiting for anything to dry up. A Panel, with just 2 pocketscrews installed is really really strong - even without the glue dry.
    My order of assembly was the following, installed front to side1, than installed opposing side 2. I then installed the full length brace to the half brace ( I did a brace scheme similar to Adire's recomendation on their sealed tempest project - so refer to their application notes for detail). This made a capitol T. (the braces I also used pocketholes to assemble.)I than installed this assembled T brace into the side, front, side piece. Once this was done I put on the driver cutout piece in that doing this piece allows you to tighten all screws into the eventually to be bottom piece. (I hope this makes sense)
    I than put on the back piece, and than the last 1/2 brace, than the top. The driver hole allows you to screw all the screws into the top. I also had 1 pocket hole at the top center of each brace. This order of assembly allowed me to use a cordless for every screw. ( a real hand saver.)(and the jig comes with 2 long and real long square head screw bits)
    Lastly I cut scrap that I cut into 4 pieces that I installed inside the box to double up the driver mounting piece for a 1.5 inch thick mounting flange. I did not counter sink the Maelstrom in that it is 3/4 inch thick and is downfiring in my case and you can't see it anyway.
    OK way more detail than a very experienced sub builder needs but hopefully helpful to someone who hasn't yet bit the bullet and done this.
    Oh yes, I tried to do measurements last night, however I had issues. The ceiling in the bar area has hidden lights under a wooden screen with a piece of smoky plexy on it ( bought the house this way - I didn't do it) And the rattles were so loud as to screw up the measurements entirely. I really need to DIY deconstruct this room, run proper cabling everywhere, and reconstruct in a more rattle averse method. Unfortunately this has to wait a while.
    I will say this, this room is in a basement, the family room is at the complete other side of the house, with no basement under it. The family room is on a slab of concrete on the main level and where my wife was sitting is in excess of 75 feet away and one floor up - again on a slab of concrete. I started to run signal sweeps starting at 10 and 12.5 hz sine waves. I ran the 10 hz than the 12.5 signal and the lighting rattled pretty badly and loudly.I than started to crank it up and at about reference level my wife ran down the stairs and asked me what the hell I was doing because the house was rattling and it scared her. [​IMG]
    OK enough output at 10 hz and 12.5 hz in a sealed enclusure to rattle the house, and pretty strongly from what she said. Not bad.
    C. OK long rant over, I hope this info helps someone.
     
  11. James Mudler

    James Mudler Stunt Coordinator

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    Carl,
    2 Maelstroms! I see you sitting in the chair like the old Memorex (sp?) ads with you hair blown back. [​IMG]
    Jack,
    Kreg also make a rocket version, it's cheaper but would not be as fast. I could not swing $140 at the time, so I picked up the $50 rocket version. I bought mine from woodcraft. I have not used it on cabinets, but do on funiture. Incredable little tool.
     
  12. Brian Bunge

    Brian Bunge Producer

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    I have a question concerning the Kreg jigs. I understand that the jig drills angled "pilot" holes into the face of the material that then come out of the end. My question is, do you also drill "pilot" holes into the face of the adjoining material. Or do you simply line up the two pieces, clamp them, and then drive the screws into the face of the adjoining material without any "pilot" holes into this piece?

    Brian
     
  13. Carl_Berg

    Carl_Berg Auditioning

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    James, that is too funny because my sister was giving me crap exactly about that. (course due to bad family genetics have less hair to blow away these days)

    I really hope some of the projector technology gets a little better and a lot cheaper soon so that I can truly do up this room like I want.

    Brian, the pilot hole made does not break through entirely the surface of the piece being drilled. Kregg sells specific square head screws to be used with their pocket holes. The have a larger head on them - kind of like a built in washer, as well as the screws are hardened and they require NO pilot hole. They actually have a built in cutter that is designed for no pilot hole use. They work really well and are about 3.95 for 100 screws so they are reasonable.

    If you ever have a need to do face frames for cabinets or frames for pictures this is the tool.

    Once done you can not see any holes or even know it was screwed together. But this is one VERY strong joining method. It puts biscuits to shame for strength - not that biscuits are made irrelevent by this tool, but in many cases can make them not needed and stronger at the same time.

    Do be aware I did this project with appleply and that screw holding capability of appleply is extreme. 1.5X stronger than regular 7 ply 3/4 inch plywood. So in MDF it is not near as strong but should allow you to glue, clamp, screw, unclamp and move on.

    C.
     
  14. Carl_Berg

    Carl_Berg Auditioning

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    Oh one more thing.

    James the "kit" I referenced also comes with the rocket portable version. The mounted jig though makes it go really quick. Clamp the jig to your work surface, quick clamp your material, drill, push lever back, slide over, pull lever forward, drill, repeat.

    Real real quick. I like good tools and this thing will find lots of uses I haven't even thought of yet.

    C.
     
  15. Jack Gilvey

    Jack Gilvey Producer

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    Thank you very much for that detailed description of the process, Carl. I'm going to look into that tool very closely, and the local Woodworker's Warehouse apparently carries it. Looking at the joint cross-section in catalogs, the prospect of rounding-over did concern me, but I guess I'd just watch the depth as you mention.

    As an aside, I went to order some 1" Baltic birch today, but the kid who originally gave me the quote called the supplier, they said they didn't carry it. As I was there for both calls, it seems they thought he meant just regular Birch ply. Anyway, they do stock the 3/4" stuff, so that's probably the way I'll go.
     
  16. Carl_Berg

    Carl_Berg Auditioning

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    Jack,

    That is a drag. They can get it it would just result in their supplier probably having to do a minimum order. Minimum orders are usually around 30 sheets, and considering that 1 inch and larger baltic birch does not have all that great a demand, I can understand why. (biggest use i have ever seen for baltic birch is in drawer sides in cabinets.) I doubt you'll ever see a 1 inch thick drawer side...

    You can always bite the bullet and glue and clamp multiple layers together. I bet 2 sheets of 1/2 inch are pretty similar in cost to a 1 inch sheet anyway. If you were going to buy 2 sheets of 1 inch, if you have a garage you could probably laminate sheets together for 1 inch thickness, use some scrap and drive a vehicle on it. Plenty of clamping pressure... While doing this choose the inside piece and screw together with 7/8 inch screws while glue dries.

    Just a thought.

    I swear though if you have 3/4 inch BB (if it is similarly strong as appleply) and cut a 1 inch strip. You can't even bend it (not even a little)let alone come even close to trying to break it over your knee. This stuff is amazingly strong.

    I'll post a pic once I get 2 coats of polyurethane on these babies.

    C.
     
  17. Jack Gilvey

    Jack Gilvey Producer

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    Yeah, I considered laminating the 1/2" stuff. For a box, I may try the method whereby a first box is built from , say, 1/2" stock, then another box is "built" onto the outside of it, overlapping all the previous joints, each side glues on slightly oversized then trimmed with a flush-trim bit. Maybe even better than going with the 1" stock.

    I know what you mean about the stiffness, even this marine ply is amazing in that way.

    Look forward to the pics.
     
  18. Kerry Hackney

    Kerry Hackney Stunt Coordinator

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    Don't know if you have used much Birch in the past so here's a note. Birch can be funny about staining. Some sheets will take the stain pretty even and then the next sheet will be VERY blotchy. By all means, use a stain pretreatment. Your results will end up much more uniform. Not that it has ever happened to me mind you [​IMG]
     

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