Haoleb's Kappa Perfect 12vq MidQ Build Thread

Haoleb

Haoleb

Audioholic Field Marshall
Alrighty, Here is going to be a step by step (sortof) build thread of the Infinity Kappa perfect 12vq MidQ subwoofer designed by our very own members avaserfi and WmAx. This is the first build thread of this subwoofer so if your intersted keep reading! The plans to this subwoofer can be referenced in this thread:

http://forums.audioholics.com/forums/showthread.php?p=429925#post429925

I am building two of these to be used in a strictly 2 channel system as a stereo pair. Powering them will be the Behringer EP2500, For the crossover, The Behringer DCX2496 and for the driver the Infinity Kappa perfect 12vq using the MidQ insert. For the cabinet I am using 3/4 inch Birch 7ply which I purchased at lowes for $55 per 4x8' sheet. I am building the sub exactly as specified in the other thread with the exception of the front panel which is going to be two peices of the 3/4 ply laminated together to allow me to flush mount the driver.

For two subs I needed just over 2 1/2 sheets of the plywood. I originally figured one sheet per sub, but forgot that I needed TWO sides and a top AND bottom. DOH!


Build Day One

Bought the plywood today and got all my peices cut. Everything is within 1/32 tolerance or less (took some time to square everything and reset the saw exactly for each cut of a new dimension. Luckly I have my dad to help rip the peices because its not a one person job ripping full sheets of plywood to exacting specifications on a table saw.



To get the most out of the plywood I ripped things according to size starting from the biggest down to the smallest. The first cut was ripping the sheet right down the middle at 24" Then going down the line to the smaller peices.

Before starting I printed out the pictures and cut list and then labeled each peice with a letter which makes it much easier to identify which peices are which and also which peices go where in the diagrams.





Once all my peices were cut I decided to start with the upper portion of the port, I rounded over the edges that are going to be the "intake" of sorts for air, It would look better for the roundovers if everything was put together with 45 degree cuts but since this is inside the subwoofer I dont really care. I know that it would have been better to have a bigger flare but this is the roundover bit I had so its going to have to do. I dont think I'll be able to round over the slot in the front of the sub though without cutting it into a bunch of peices and then re assembling it which I am not going to do as it would only weaken the front baffle and make things more complicated.



I very lightly sanded the peices with some 220 grit on a sanding block made from a peice of wood not needed. before gluing them to make sure all my edges are square.



My two upper port portions glued and nailed together with a brad nailer.



For glue I'm using some titebond 3, I have a bunch of titebond 2 already but this says its the strongest there is so.. whatever. I'll give it a try :) I also used a small peice as a spacer to make sure the 3/4" that overhangs to join with the next part of the port on the back was exactly 3/4" When sanding I like to use the wood block as it will not round over your edges and will allow you to sand very evenly. I am only doing a light sanding to remove any dirt and anything left behind from the saw even though I did install a new blade before starting.

Thats it for today! I'll just keep assembling the inside parts for now because I need to wait for my drivers and binding posts to arrive before I can really finish the front and back panels and make this thing start looking like a real sub. Stay Tuned!
 
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Adam

Adam

Audioholic Jedi
Impressive! You are very fast. Andrew just put that thread up a couple of days ago. Nicely done.
 
Haoleb

Haoleb

Audioholic Field Marshall
Impressive! You are very fast. Andrew just put that thread up a couple of days ago. Nicely done.
When I get my mind set on something I just go and do it. I only decided I wanted to build these yesterday afternoon.:eek:
 
WmAx

WmAx

Audioholic Samurai
A
For glue I'm using some titebond 3, I have a bunch of titebond 2 already but this says its the strongest there is so.. whatever.
In actual 3rd party analysis/comparison, subjecting joints to measured force, standard aliphatic resin is the strongest glue. Titebond Original is aliphatic resin. II and III are ironically, weaker, at least for dry indoor use, as compared to outdoor use and moisture exposure use, where the newer formulations may have specific advantages.

-Chris
 
Adam

Adam

Audioholic Jedi
When I get my mind set on something I just go and do it. I only decided I wanted to build these yesterday afternoon.:eek:
I am a huge procrastinator, so I'm very impressed with this! I really look forward to seeing your progress on it. Andrew's CAD diagrams are great (and I'm sure that he and Chris have been helping out a lot more than just that), but seeing real world photos of a work in progress are very educational.
 
Haoleb

Haoleb

Audioholic Field Marshall
In actual 3rd party analysis/comparison, subjecting joints to measured force, standard aliphatic resin is the strongest glue. Titebond Original is aliphatic resin. II and III are ironically, weaker, at least for dry indoor use, as compared to outdoor use and moisture exposure use, where the newer formulations may have specific advantages.

-Chris
I'm just going to pretend that you didnt say that... :)

Now i'll Probably wake up having nightmares of my subs blowing apart because I used the number 3 vs the original!

I did a little test gluing some scrap peices of mahogany together butt jointed with just glue and I only let it dry for an hour or two and had a hard time tearing it apart with just my hands so I think it will be sufficient once its fully cured and nailed.
 
Haoleb

Haoleb

Audioholic Field Marshall
Just realized I made my first goof. When I decided to do 2 sheets of ply for the front baffle I didnt look closely enough at the design to see that it sits Inside, I thought it mounted on the outside of the other panels. I did not account for having the added 3/4 inch when I cut my second set of front baffles so that they could cover all the sides and top. Of course, This is only 20 minutes after I laminated my first two panels and I could not get them back apart.

Luckly I have two more front baffles and some extra plywood.

If I were to just laminate a small portion, big enough to allow for the driver mounting flush how is the decreased volume in the sub going to affect performance? I dont have a plunge router or a circle jig so I may end up just giving the flush mounting the old boot anyway and sticking with the original plans.
 
avaserfi

avaserfi

Audioholic Ninja
I'm just going to pretend that you didnt say that... :)

Now i'll Probably wake up having nightmares of my subs blowing apart because I used the number 3 vs the original!

I did a little test gluing some scrap peices of mahogany together butt jointed with just glue and I only let it dry for an hour or two and had a hard time tearing it apart with just my hands so I think it will be sufficient once its fully cured and nailed.
No worries here. My original build used number 3 due to weather conditions.

If I were to just laminate a small portion, big enough to allow for the driver mounting flush how is the decreased volume in the sub going to affect performance? I dont have a plunge router or a circle jig so I may end up just giving the flush mounting the old boot anyway and sticking with the original plans.
The volume change would most likely not be substantial enough to change performance noticeably.
 
Guiria

Guiria

Senior Audioholic
Keep the build updates coming...very interesting.
 
Haoleb

Haoleb

Audioholic Field Marshall
Alrighty. Build Day 2

Spent most of the day working on the subs, So far I have the entire port/bracing assembly completed and have got one coat of paint on the areas inside the sub that will be seen in the port.

One thing I did not really realize looking at the design on paper is just how big these really are! Its going to be almost like having two 3/4 size washing machines in my room :eek:



Assembling the rest of the port peices into one peice. I measure, glue, clamp, measure, and then nail with a brad nailer. Each joint has about 15 nails in it. The big cross brace is just in there temporaraly to give me the correct measurement between the two sides of the port.



Perfectly square! :D



A small speed square is a MUST for doing projects like this with any precision. They are only about 6 bucks at the hardware store. Dont go without it.



Attaching the small brace to the port. The smaller peices on each side are just spacers I cut to keep it all square while I was gluing and nailing the peice on. They were taken out afterwards.



Goof up on the front baffle solved. Luckly I had enough extra plywood to recut a pair of front baffles that is 3/4 inch bigger on each side to allow me to have a double thickness baffle without altering the box volume. This will also give me a better face because it wont have all the joints showing. I think the plans should be changed to go with this addition as it will only make the box even more rigid (and front heavy unfortunately)



fully assembled and onto painting the ports! I sanded and bondo'd my nail holes even though you'd never see them anyway. Primer coat first. I also painted the bottom panel and part of the back panel.
 
Haoleb

Haoleb

Audioholic Field Marshall


back panel. The small cutouts are for the binding post plates.



Its pretty obvious that for the outside I am going to have to put a thin coat of bondo over the entire plywood surface for a professional looking finish. It will be quite a bit of extra work but I think it will be worth it. So far I am going to do with a semi gloss black, But i'll have to see how these inside peices turn out when I am done painting them before I make my final decision.





Spraying with an HVLP sprayer, Spraypaint simply will not give me good results on something this large. I am by no means a painter so hopefully it will turn out ok but from what I have seen so far it should be a breeze :D

Thats all for today. I had hoped to get the inside assembly attached to the base panel today but am going to sand and repaint the port and bottom panels again for a better finish as I am simply not satisfied with how they are now. Its better to just take the time and do it right the first time then rush and overlook things.

I can say without a doubt that this is looking to be the finest thing that has ever been created by myself up to this point. I have high hopes for this project! :D
 
WmAx

WmAx

Audioholic Samurai


back panel. The small cutouts are for the binding post plates.



Its pretty obvious that for the outside I am going to have to put a thin coat of bondo over the entire plywood surface for a professional looking finish. It will be quite a bit of extra work but I think it will be worth it. So far I am going to do with a semi gloss black, But i'll have to see how these inside peices turn out when I am done painting them before I make my final decision.





Spraying with an HVLP sprayer, Spraypaint simply will not give me good results on something this large. I am by no means a painter so hopefully it will turn out ok but from what I have seen so far it should be a breeze :D

Thats all for today. I had hoped to get the inside assembly attached to the base panel today but am going to sand and repaint the port and bottom panels again for a better finish as I am simply not satisfied with how they are now. Its better to just take the time and do it right the first time then rush and overlook things.

I can say without a doubt that this is looking to be the finest thing that has ever been created by myself up to this point. I have high hopes for this project! :D
Another option is laminate it with Wilson Art sheet laminates. They are not cheap, though.

-Chris
 
TLS Guy

TLS Guy

Seriously, I have no life.
Just realized I made my first goof. When I decided to do 2 sheets of ply for the front baffle I didnt look closely enough at the design to see that it sits Inside, I thought it mounted on the outside of the other panels. I did not account for having the added 3/4 inch when I cut my second set of front baffles so that they could cover all the sides and top. Of course, This is only 20 minutes after I laminated my first two panels and I could not get them back apart.

Luckly I have two more front baffles and some extra plywood.

If I were to just laminate a small portion, big enough to allow for the driver mounting flush how is the decreased volume in the sub going to affect performance? I dont have a plunge router or a circle jig so I may end up just giving the flush mounting the old boot anyway and sticking with the original plans.
Those troubles are just part of the fun! Very good work. I think you will be pleased you chose to undertake this. Next build the rest of your speakers!
 
Haoleb

Haoleb

Audioholic Field Marshall
Another option is laminate it with Wilson Art sheet laminates. They are not cheap, though.

-Chris
I did consider doing a veneer or some type of laminate but want to try and keep the costs down as much as I can. I am already beyond what I was ready to spend on a commerially available sub :eek: If the painting doesnt turn out to my standards there's always the option of doing a veneer down the road but so long as I take the time to properly prep everything it should be good.

My biggest concern is how i'm going to cut the slot in the fascia while keeping it perfectly straight and square. A jigsaw is already out of the question that will end up looking like crap no matter how carefully I do it. I'm also not sure how I am going to flare the slot.
 
Sheep

Sheep

Audioholic Warlord
Nice work. I want to get started on mine, but I haven't heard back on my Ep1500.

SheepStar
 
Haoleb

Haoleb

Audioholic Field Marshall
Nice work. I want to get started on mine, but I haven't heard back on my Ep1500.

SheepStar

Speaking of that, I kinda think the deal I was working on a used EP2500 may have fallen though. I pray it hasnt otherwise its going to add a couple hundred more onto the price I had not expected :( The cost of building these is quickly adding up. By the time you get the paint, sandpaper, mineral spirits, bondo, spikes, speaker wire, insulation, etc etc etc next time I think i'll figure my costs, then add 500 on top of that. Too late to turn back now though!
 
mike c

mike c

Audioholic Warlord
Nice work. I want to get started on mine, but I haven't heard back on my Ep1500.

SheepStar
unless the 1500 was ultra cheap over the 2500, i'd get the 2500 ... the 1500 bench tests seem to put it way below rated specs.

see this bench test:
http://www.avsforum.com/avs-vb/showthread.php?p=10749440&highlight=behringer+ep1500#post10749440
http://www.avsforum.com/avs-vb/showthread.php?p=10748192&highlight=behringer+ep1500#post10748192
http://www.avsforum.com/avs-vb/showthread.php?p=10747784&highlight=behringer+ep1500#post10747784
 
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WmAx

WmAx

Audioholic Samurai
I must disagree with your "way below rated specs" comment. The EP1500 meets or nearly meets all of the tests with the exception of the stereo 2 ohms and 4 ohms bridged mono, where it is off by a touch over 20 percent from ratings . It meets or comes very close to meeting both 8 ohm stereo and 4 ohm stereo rating specs and it is more true to the specs than most amplifiers measured, if you want to get picky. :)

Want an example of amps with truly "way below rated specs" performance? Refer to Crown XTi1000, The Butticker amp or the Dayton 1000W rack mount sub amp. These amps barely exceed 50 percent(!) of their spec, or even do worse in some cases.

Now, I do agree with avoidance of buying the EP1500 unless one gets a killer deal. It is only $50 lower($300) in price as compared to the Ep2500($350), but the Ep2500 has almost 2x the power output across the board.

-Chris
 
Sheep

Sheep

Audioholic Warlord
You guys must remember that these amps are 500 and 600 dollars in Canada. I found an Ep1500 for 250, which I'm trying to work down to 200. If I can't get the amp, I'll have to wait and save. Musicians friend has them for less, but you need to factor in shipping and duty.

Mike, the EP1500 will be enough for what I need, regardless of a 20% drop in performance.

SheepStar
 

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