Simple 12" Infinity Kappa VQ MidQ Plans

[abboudc]

Very very nice.

Can i ask what the total project cost was?
Kappa - $200
Amp - $350
Wood - $50??
Rock Wool - $??
Anything else?

How did you finish the outside of the box -- wrap it in fabric, spray paint, etc? Anyone got any finished pics -- it seems several of these were works-in-progress a couple weeks ago...

 

[GTHill]

Very very nice.

Can i ask what the total project cost was?
Kappa - $200
Amp - $350
Wood - $50??
Rock Wool - $??
Anything else?

How did you finish the outside of the box -- wrap it in fabric, spray paint, etc? Anyone got any finished pics -- it seems several of these were works-in-progress a couple weeks ago...

I also bought the EQ... I think it was $200. So, you need the EQ or a crossover to add to that list.

I bought the OC705 and it was $130. However, that could do about 20 of these subs. So, I would budget $20 (shipped) or so for the OC705.

Wood... If you use the plywood as suggested, at least $50. It is sometimes above $50 a sheet and you will have to buy two sheets. I used MDF (see my build thread) and that takes two sheets at $22 per sheet.

I'm also building a speaker grill and a few other accessories that will add up a bit.

Gene

 

[avaserfi]

Very very nice.

Can i ask what the total project cost was?
Kappa - $200
Amp - $350
Wood - $50??
Rock Wool - $??
Anything else?

How did you finish the outside of the box -- wrap it in fabric, spray paint, etc? Anyone got any finished pics -- it seems several of these were works-in-progress a couple weeks ago...

I highly recommend using a quality plywood over MDF this will likely cost $100 for a subwoofer. Along side this you will need some wire, feet (or casters) for the subwoofer, ideally a DCX2496, wood glue etc...I believe my build, which was far more complicated [and expensive] because of using solid oak bracing and a doubled over port as well as more complicated bracing, ended up costing about $1,000 for a single subwoofer including the EP2500 and DCX2496.

User Haoleb built a pair for himself and reviewed them here. I believe he links pictures to his final product in the review as well.

 

[KiltedNerd]

OK, I am coming in a little late on this but I think I am going to try one of these. Just a few things I wanted to make sure of...


the amp you are speaking of, is it a Behringer EP2500?

if so, are you bridging it to the Kappa?

isnt the RMS on the sub like 70-400 with a 1600 peak?

And the amp 1200 per channel? I would think you could drive two off of one amp without much problem which is what I am hoping to do....

 

[avaserfi]

the amp you are speaking of, is it a Behringer EP2500?

Yes, that is the amp.

if so, are you bridging it to the Kappa?

You can bridge the Kappa, but I always recommend use of stereo subwoofers.

isnt the RMS on the sub like 70-400 with a 1600 peak?

Driver power rating isn't indicative to real life power capabilities. The VQ can easily make use of the full power of a bridged EP2500. Of course, in actual use you would never use so much output.

And the amp 1200 per channel? I would think you could drive two off of one amp without much problem which is what I am hoping to do....

This would certainly be the ideal situation.

 

[armstrr]

ok, guys, i have read this build thread with great interest.

i am a want to be wood worker, and i need an excuse to get into the shop...well sort of.

i have had an av123.com mwf-15 b-stock on order for over 3 months. i paid $525 including shipping. it has not arrived and i am sick of excuses.

so i am looking at 3 possiblilities, and by the sounds of it, you guys have a tremendous understanding of subs and their cababilities.

option one: do nothing, perhaps the mwf-15 will ship in the next year or two.

option two: build the sub you have described. i have all the tools (and then some) to do this.

option three: build a dual 12" rythmic servo kit. the owner will have a 600w amp he will trade for the 370w amp that sold with the kit. so this would be a dual 12" sealed kit in a 4 cubic foot box. i can buy this kit from a guy and then trade the amp in for the larger one. this will set me back probably $550 + the box materials.

here are a couple of questions. i have a denon 2809ci which has all 3 of Audyssey's eq technologies. would this allow me to forgo the eq you guys are using?

another question. the amp that you suggest: how many amps does it draw according to the back plate? also, is it possible to adjust the volume of the 2 channels seperately? i have a couple of buttkicker LFEs to power and i am wondering if i could use one channel to power the sub, the other the buttkickers. i sold my buttkicker amp, which i think was 2 ohm cabable, so i have both sets of speaker wires terminating at the same output posts, so does that mean this is a 2 ohm load? ( i need to check that out, but i'm sure i could change the wiring to make it an 8ohm load).

if i go the kappa route and power the lfes using another amp, that would free up the other sub amp to power another sub for the cost of the kappa and box...interesting!


so of the 3 options, does one stand out in your mind as the best performer given the cost factor? assume the eq can be left out due to audyssey multeq...unless you inform me otherwise.

oh, and as an edit: I will be using this 95% for home theater use. my room is 13.5'x17'x7'8"

thanks!!!

 

[jamie2112]

Build Andrew and Chris's sub. I just got finished and it is unbelieveable. I am not even using the amp suggested. I am using a 400 watt peavy amp from the late 70's and it still kills. I will be getting a behringer amp shortly but I would highly recommend this build......

 

[Matt34]

Build Andrew and Chris's sub. I just got finished and it is unbelieveable. I am not even using the amp suggested. I am using a 400 watt peavy amp from the late 70's and it still kills. I will be getting a behringer amp shortly but I would highly recommend this build......

Hey Jamie,

What other subs have you heard to compare this too? I'm still tossing around the idea of doing one of these builds.

 

[jamie2112]

Hey Jamie,

What other subs have you heard to compare this too? I'm still tossing around the idea of doing one of these builds.

Well I got to tell ya I am very hard to impress when it comes to sound. The sub smokes the SVS pb plus that I compared it to and my friend in DC has 2 HSU vtf3 mk and it killed that as well, with a peavy cs 800 amp which is a dinosaur I will be adding the Behringer 2500 this week and I am sure it will be that much better. It is a big sub but my god I corner loaded it at my partners place and his neighbor came over and said her house was shaking. This was about 30 feet away from the corner of the house I set it up on. I was impressed to say the least. I now have the sub bug and may be building a slew of subs.... Matt I would not even hesitate to build this sub it is amazing truly...

 

[avaserfi]

here are a couple of questions. i have a denon 2809ci which has all 3 of Audyssey's eq technologies. would this allow me to forgo the eq you guys are using?

At minimum you will need an infrasonic filter in place at 20Hz, Audyssey will not do this. There are cheaper options available than the DCX recommended such as the Reckhorn B1.

another question. the amp that you suggest: how many amps does it draw according to the back plate? also, is it possible to adjust the volume of the 2 channels seperately? i have a couple of buttkicker LFEs to power and i am wondering if i could use one channel to power the sub, the other the buttkickers. i sold my buttkicker amp, which i think was 2 ohm cabable, so i have both sets of speaker wires terminating at the same output posts, so does that mean this is a 2 ohm load? ( i need to check that out, but i'm sure i could change the wiring to make it an 8ohm load).

The EP2500 will draw up to 20 amps if required. The back plate is incorrect. Gain on each channel can be adjusted separately and the EP2500 is stable at 2 ohms.

so of the 3 options, does one stand out in your mind as the best performer given the cost factor? assume the eq can be left out due to audyssey multeq...unless you inform me otherwise.

The Kappa sub will be the highest performing unit of the three options without a doubt. In such a situation I know what option I would choose .

 

[avaserfi]

Glad you are enjoying those subs Jamie, have you decided on mains yet?

 

[jamie2112]

Glad you are enjoying those subs Jamie, have you decided on mains yet?

I am sticking with my Matrix 804s. I have yet to hear a cabinet that I liked better. The things are braced to death and sound amazing to me. Of course if I could afford the 800d or the 804N then I would go for those. The only thing I have heard yet that I liked better was a $20,000 pair of Wilsons and no way would I pay that price. I do however love the sub and when I get my 2500 this week I am sure it will sound even better. I will also be using a dbx driverack as I just happen to have one sitting for the eq. Thanks again Andrew and Chris for designing an amazing subwoofer.

 

[armstrr]

At minimum you will need an infrasonic filter in place at 20Hz, Audyssey will not do this. There are cheaper options available than the DCX recommended such as the Reckhorn B1.



The EP2500 will draw up to 20 amps if required. The back plate is incorrect. Gain on each channel can be adjusted separately and the EP2500 is stable at 2 ohms.



The Kappa sub will be the highest performing unit of the three options without a doubt. In such a situation I know what option I would choose .

alright, i'm sold. as soon as my money for the mwf15 is returned, the build will begin!!! i'll be back for help soon!

 

[WmAx]

alright, i'm sold. as soon as my money for the mwf15 is returned, the build will begin!!! i'll be back for help soon!

While Andrew is correct that there are cheaper options than the DCX2496; there is not a better option for optimal set up/integration if your budget can allow for it.

-Chris

 

[armstrr]

While Andrew is correct that there are cheaper options than the DCX2496; there is not a better option for optimal set up/integration if your budget can allow for it.

-Chris

i'll keep my eye out for a used one, or add it as funds allow. i don't normally run at reference levels either...

anything you guys would add or change to this sub if you were to design/build another?

 

[mike c]

anything you guys would add or change to this sub if you were to design/build another?

i would make it taller so it would have less footprint ... i believe most rooms need the floorspace more than the airspace

 

[WmAx]

i'll keep my eye out for a used one, or add it as funds allow. i don't normally run at reference levels either...

anything you guys would add or change to this sub if you were to design/build another?

No, we carefully designed this cabinet for optimal bandwidth, SPL and fidelity from 19Hz - 85 Hz. It acts like a text book perfect example as a result with no performance degradation due to things like insufficient port air flow, etc..

The only thing to change if you wish, is the ratio of height/depth/width to fit your personal space better. You could make it taller as Mike C. suggested. But you must keep the original internal net volume and you must keep the port identical dimensions to the original specified. If you need, you can shift the port dimensions some as long as the cross sectional area is kept identical, and that you do not make the port thinner; if anything you must shift the port to a more squared ratio. If you make it thinner than it is, non-linear air behavior(s) may occur, causing problems in performance/tuning. Be very careful shifting the dimensions beyond those published is my only point, or you may end up with diminished performance.

Realize that one of the specified and intended materials is a high density fiberglass or mineral wool board, of 4-8lbs/ft^3 density. This is over 2x the density of materials you find in stores like Lowe's or your local hardware store. You can buy this material online or get it at local commercial insulation contractors. I sometimes send the material to people if they need it, but I don't do it all that often and I do not offer rush services. I do it only as a last resort source for people with no way to get it otherwise.

-Chris

 

[allargon]

Instead of rock wool or polyfill (which also ain't cheap), have you guys considered spraying the cut sheets with a rubber like substance similar to but obviously not as hard as truck bed liner to cut down on resonance?

 

[WmAx]

Instead of rock wool or polyfill (which also ain't cheap), have you guys considered spraying the cut sheets with a rubber like substance similar to but obviously not as hard as truck bed liner to cut down on resonance?

Applying a mass loaded dampening material like the material you mention, or Dynamat, is useless, as the resonance that is reduced using the high density fiberglass or high density rockwool is that of acoustic wave modes based on the internal dimensions of the cabinet. [You mentioned polyfill, but this material is not very valuable as an acoustic absorption material.] The resonance affected by the mass loaded dampening material is panel resonance. These are two disticly different things. Also, due to the relatively low frequencies subject to a subwoofer do not normally require any special panel resonance solutions, as it's easy to push panel the 1st panel resonance over the bandwidth of a subwoofer.

-Chris

 

[allargon]

Applying a mass loaded dampening material like the material you mention, or Dynamat, is useless, as the resonance that is reduced using the high density fiberglass or high density rockwool is that of acoustic wave modes based on the internal dimensions of the cabinet. [You mentioned polyfill, but this material is not very valuable as an acoustic absorption material.] The resonance affected by the mass loaded dampening material is panel resonance. These are two disticly different things. Also, due to the relatively low frequencies subject to a subwoofer do not normally require any special panel resonance solutions, as it's easy to push panel the 1st panel resonance over the bandwidth of a subwoofer.

Crap... I despise working with any potential carcinogens like rock wool, insulation, etc. Thanks for the 411.