15" cinema subs cost how much?!?!

Soldato
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Blimey. So obviously this isn't a PC build or a mod. People have posted their carpentry projects though and we all like bass, so here goes.

For the past three years I have been very slowly building up my cinema rig. It has lots of Tag Mclaren. I was happy with the 8" sub I had for ages, but then I decided to add my first purchase speakers and amp to the system as well. I originally bought these Sonus Fabers as my front speakers, but then I had a result and ended up with some Revel M105s. Which cost three times as much (the ones on taller stands)

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Then I recently bought the 70" TV there and it came with a new sound mode for my Tag to chew on. Instead of it using just the centre for the most part it uses the two front speakers far more. Hence why I fancied adding the Fabers to the array. Well the problem is it sounded so good that I decided to keep them there. Just one problem, the sub is basically gone. It had large boots to fill and it's done its job well. I wanted something a bit bigger, though.

I looked around at cinema subs but they all seem to be sniffing something. I've had a lot of experience with speakers and especially subs (used to compete back in the 90s) and whilst I understand that nice subwoofers are nice, the prices in cinema audio seem to be a bit of a joke given that subs are just air pistons, and their capabilities are far more physically based than being posh. Bottom line? the drop and the bass is not something people should get all SQL and snake oily about. As I said, it's an air piston it doesn't need to do it in some audiophile form. The fact is car subwoofers have had more R&D and become more and more mean over the years. They are also pretty damn cheap now for a ton of noise too.

So my first idea was to make a cheeky offer on a car built sub, then make the box look nice. So I ended up paying £21 for this cabinet over the cost of just the woofer.

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My goal was to take out the vents, paint them black, and then cut off the horrid lip and veneer it. Only problem? router malfunction. Well actually not the router, the bit. The bearing came off and before I knew it it was game over.

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Whoops.

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Now a part of me was pretty angry given my experience that I tried to do a cheap hack like that in the first place. So once I had asked someone to take it to the tip I decided not to be so lazy and just do it properly. 32hz down to 24.

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I then went on a tool buying spree. I also sent the design to a local place with a CNC saw, for super precise cuts. I went with 18mm hidrafugal MDF. It is water proof, fire proof, and much harder and less fluffy than regular MDF.

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Build port duct.

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Port said port duct to reduce chuffing and turbulence.

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Paint said port duct.

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Paint inside of right, put right on bottom and port duct on front and left.

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Realise you wasted half a day painting the bottom too soon and that it would need a F ton of holes drilled and countersunk into it.

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Mark out sub hole and place top on.

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Put back on.

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Fill twice.

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Sand like buggery.

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Pre drill and sink top.

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Fit top and return to filling like buggery.

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Then sand like buggery again.

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Fit woofer and feel elated but quite terrified.

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Buy amp.

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And bars.

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Repaint bottom.

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Then sit and watch it dry for a bit..

Things to come. Ebony veneer starts tomorrow.

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Then.

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Before finally putting two layers of sound deadening in the top and bottom. I haven't done it now because it is heavy as balls already and the deadening adds another 5kg or so.

Ask friend to make posh legs with spikes.

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And wait for said friend to make them for you :)
 
Soldato
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Ohh I guess you mean the centre. Have you seen it?

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It's piggin massive :D I would like to know where you would put it. I used to have a normal centre on a stand.

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But I wanted to bi amp it so I didn't leave an amp channel with no load on it. I got the Linn, which is awesome as it has much more oomph. Just one problem, if you put it on the stand you cant move.
 
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Jeez look at the size of that driver. I hope you've bought some extra paracetmol... !

Yeah see I told myself if I was to come out of retirement and do this again it would be the forever sub.

I gave it a test last night on the amp. I haven't giggled like that in many years. I used this as a test track.

https://www.youtube.com/watch?v=2ZG9hVlJo18

And when it hits 33hz the thing just leaps to life lmao. It shook the entire house.

Been very busy today. I had my mother nagging in my ear when measuring the amp, and so inevitably this ended up happening.

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One thing I can not do is listen to a nagging woman and multi task at the same time. After a firm telling off I got on with fixing it.

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It then got a skim (two lots) of filler.

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And then today.

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The bars I ordered came too.

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Easily the hardest part so far. It's not very well trimmed, but I risked seriously damaging it by going too far.

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I need to peel the mask off the bottom to trim it up, the rest is done with a file or sand paper.
 
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I haven't ditched it. Weather has been conspiring against me. Last night I got so fed up of it I decided to open the back doors and do the top in here.

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I made but one error. I should have masked the veneer already on there to stop the glue getting into the grain. I have gotten 99% of that off, but fear going through the veneer if I continue. So, I am just going to have to accept it.

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The legs are done and here, with the inserts for the wood itself. I will get pics of those later. Might bash out a side tonight, we'll see.
 
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Friend of my dad was an electronics engineer and designed his own valve amp which was something to behold but this is a very impressive project too.

When I was transitioning from a somewhat flabby 14" Yamaha sub to a much better 12" REL I thought I'd try running both from my then Yamaha DSP A1 amp as it had two sub outputs. Didn't take long for my neighbor to come knocking as they said stuff was falling off the wall!

Yeah I got a noise pollution notice in the 90s. I had an addiction to loud bass. At the time I had a 18" Cerwin Vega Stroker in their T36 Intense cabinet. I realised it was better to sell it before I ended up in prison lol.

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I had 10" Macrom compression drivers in the cupboard flaps up top (they had horns in the middle). I had a Rogers E40 valve amp running those and a Soundmaster amp running 2 ohms at about 2kw into the sub.

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There was a guy opposite about 5 doors up that still had those crittle (sic) council windows. I managed to crack one. That sub was barbaric, and even more so because it was in a trapezoidal folded horn. So the further you got from it the more it just made everything shake.
 
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Can you guys go into more detail about those competitions?

Sound offs. You had classes and strict rules. So for example in one comp you had to use an amp with no more than 20w per channel (with combined 40w bridged) then design your car around getting as much SPL (sound pressure level) out of it as you could, with that range of amplifier.

However, those like me (who were in the know) would use what was called "the cheater amp" and get banned :D

So why was it the cheater amp? well, there was a certain Phoenix Gold amplifier released many years ago. It was called the Phoenix Gold MPS 2220. It was so over designed and over built (triple gold plated PCB traces) that it could handle about twenty times that power. Then someone realised that if you played with the inside a little bit the amp could run at 1/4 of an ohm.

So think about it like this. The amp is made to run at 40w into 4ohms. However, theoretically (some is lost in heat) each time you half the ohm load you double the power. So at 2 ohms it would put out 80w. At 1ohm it would put out 160w. At 1/2 an ohm it would put out 320. Drop that in half again? you are talking 600 watts.

And that's why it was called the cheater amp and eventually banned from competition :D

I joined Team PG when I got to the USA and met all of the guys who ran it. Awesome bunch. If I can find my old comp pics I will upload them.
 
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I won't butter it up mate, it's hard and it's scary.

Most people now use wood glue, but this means you need to vacuum bag the parts and then cut them at 45' and build it that way. Which for me was not an option. As such I used Evo Stik, AKA "Skinhead space costume". It absolutely stunk the house down. Also, once it goes on? that's it. You are supposed to use wooden pieces to line them up but I would have needed loads. So instead of cutting the panels roughly to size I had to leave them over sized which meant I cracked it a lot when rolling/scraping it down. This meant rough edges, which required more work. The reason it looks so much better now is because I went in with a artist brush and some satin black. Wherever there was like, patches between the black stripes I touched in. So its much more seamless than it was.

I did watch a guide or ten. This was about the best.


However, what you don't realise is that he has obviously had a lot of practice and has made his mistakes off camera. So all of mine? I had to fix.

He does make a mistake though. Well, two for me. Firstly he is using a roller to apply the glue. I thought "Oh cool that will make it easy!". Sadly I did not realise that my glue was way stronger than his and my roller head fell apart and stuck to the cabinet. I had to pick it all out whilst it was wet. I had to use the scrapers that come with the glue, and it was unbelievably messy and horrible. There are companies who do iron on, personally I would use that. I highly doubt it has the holding power of what I used, but lets face it you usually just sit and look at speakers and never touch them.

You are supposed to use a scraper to apply veneer. Thankfully my roller had one on the other side. Lots of pressure. A roller (even a wooden one) does not apply enough.


IDK what roller he is using there but it's obviously a special one.

All I know is I never ever want to do it again. Especially not on this scale. That said it was always going to be "the forever sub" so unless someone is crazy enough to try and steal it? it will be lol. I've even got a spare woofer, so yeah for sure never have to do it again.

Had I known all of this? I would have painted the whole thing. That said I am glad I went to hell and back with it.
 
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Love a good box build! Keep meaning to box up the IDMax 12's for home use (currently on a BK Monolith DF, so no real urgency)

Veneering has always scared me, how hard is it without the clamps/presses etc?

If those are the 12s I am thinking about they were one of the best ever made. IIRC Image Dynamics sold out to China, along with Soundstream and loads of others.
 
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Ah. It seems I forgot to post up another step. I've been really sick (med change, side effects). I got it done then was supposed to post it when I got home, but was too busy watching Netflix and listening to records :D

Any way, I fitted the legs. It was a lot harder than I planned on it being. Firstly I needed to drill 10mm holes. However, if I had tried to do this it would have blown through into the port duct and looked terrible. I also needed them to be flat inside, and not curved like the tip of most drill bits.

I started out with a bradpoint bit.

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Mostly because of the point. This means I don't have to drill a pilot hole. I bought these things.

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Which clamp onto the bit and stop it pulling itself in. I pre drilled all of the holes deep enough so that I could use a mill bit. This is totally flat at the cutting end.

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Which was locked off at 11mm depth. Then you bolt in the metal receivers, which give you a solid metal threaded hole.

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So that is done also. When I am done with the PU clear I will repaint the bottom and entrance to the port duct. That will be the last job to do before packing it up and having someone move it to my place :)

Edit. Oh ruddy heck. My lazy two weeks meant I missed even more ffs.

OK so when I went home I looked at the coffee table this is replacing. It was a bit of a mess tbh. I don't want the top of the sub ending up like that.

So I bought a remnant of ox blood leather.

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And ordered pinking shears.

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I am going to make a sash to put stuff on. The left overs can make some coasters to put my coffee on etc.
 
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Started working with the leather. Hardest part was getting it squared and learning how to cut it. Turned into a bit of an ordeal, but it's there. I've cut two coasters also, and have loads of spare. I want to test the pinking shears on scrap first, as it is really thick.

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Final coat of PU is down. I will let it harden fully now before tackling the last black work.

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As you can see the port is absolutely filthy. So I need to make a tool that I can wrap a cloth around and clean it out properly. I do not want to even think about running a sub in there until it's sparkling. I decorated my room with dust quite a few times in the past.

The leather work is done also.

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