Simple 12" Infinity Kappa VQ MidQ Plans

[WmAx]

Not to hijack the thread, but if one wanted less extension (25Hz max) would it possible to put these drivers in a smaller sealed enclosure?

Yes, but the output ability(SPL) would decrease substantially and the distortion would raise at any given SPL in the lowest octave due to the increased cone/motor movement required. A 12" Kappa Perfect subwoofer will slightly exceed a Velodyne DD-12, which is a high end commercial sealed design.High power is needed along with a precision DSP loudspeaker management device, like the Behringer DCX2496, if you want to achieve good FR into lower frequencies without the amp distorting and also be able to use protection filters to prevent the driver from being over-driven. If your budget can withstand a more expensive driver, the JL Audio W7 drivers(12" is about $430 on eBay) can be used in small sealed cabinet with some really fantastic results, if you have lots of power and a DSP management system to shape/correct it's response.

-Chris

 

[Guiria]

Not to hijack the thread, but if one wanted less extension (25Hz max) would it possible to put these drivers in a smaller sealed enclosure?

A discussion of a sealed design has been covered quite extensively in this thread.

http://forums.audioholics.com/forums/showthread.php?t=44354

FYI

 

[Sheep]

This was a relatively time consuming process. I probably won't have time to do something so detailed for the 10VQ, but would be willing to help you with your build.

I didn't even see this! Thanks buddy! You're so awesome!

SheepStar

 

[jboogie]

plate amp mounting

DOH! Thanks guys, I hadn't really gotten that far...I will have to study some options before I can answer where I will mount it!

I do have all of my pieces cut though. I am looking forward to making some more progress.

 

[Sheep]

DOH! Thanks guys, I hadn't really gotten that far...I will have to study some options before I can answer where I will mount it!

I do have all of my pieces cut though. I am looking forward to making some more progress.

I wouldn't bother with a plate amp. Euro Power FTW.

SheepStrr

 

[avaserfi]

DOH! Thanks guys, I hadn't really gotten that far...I will have to study some options before I can answer where I will mount it!

I do have all of my pieces cut though. I am looking forward to making some more progress.

Since it seems as if you already have the plate amp I would recommend making a small, simple, separate enclosure for the plate amp. This will give you the option to upgrade your amplifier in the future. This will allow for a good looking solution with your plate amp while keeping maximum versatility.

 

[jinjuku]

I was looking at the site that is selling the Kappa Perfect. They have a ton of subs. Out of all these, what made the Kappa the perfect pick?

 

[avaserfi]

I was looking at the site that is selling the Kappa Perfect. They have a ton of subs. Out of all these, what made the Kappa the perfect pick?

The versatility of the variable motor and its ability to produce extreme SPL at low distortion among other things. Simply put the Kappa VQ subs are extraordinarily well designed as shown by credible 3rd party measurements.

 

[jboogie]

Since it seems as if you already have the plate amp I would recommend making a small, simple, separate enclosure for the plate amp. This will give you the option to upgrade your amplifier in the future. This will allow for a good looking solution with your plate amp while keeping maximum versatility.

Yes, I do have the plate amp already. And I had thought of this very idea, it is what I will probably end up doing. I am thinking of making a small decorative box that will sit on top of the sub itself.

 

[Djizasse]

Guys, I'm in
Just ordered the 12 VQ (just one for now). I'm now looking for a Ep2500 in Europe.

My build is going to be much slower that Haoleb's, so don't expect any news in a week or two

 

[Haoleb]

Guys, I'm in
Just ordered the 12 VQ (just one for now). I'm now looking for a Ep2500 in Europe.

My build is going to be much slower that Haoleb's, so don't expect any news in a week or two

What do you mean, MINE is going slow! Been working on them for over a week already! Even took off work early today so i could come home and get a coat of primer on before it started raining (which it did about a minute before I was done painting my second sub) No chance of getting a coat of color on today

If you ever need any help along the way feel free to ask! Just take your time and im sure they will turn out fantastic

 

[Djizasse]

You're doing a great job

I'm not shy. I'll definitely ask, although looking at you work log already answers many questions. Lot's of attention to detail.

The Ep2500 is on its way. There's no going back now

 

[jboogie]

Rock wool

Just how important is the rock wool? I looked it up and it is VERY expensive and only available in somewhat large amounts. Is there a viable alternative? Will it make all of the difference in the sound quality of the speaker?

I am ready for glue up tomorrow and just realized that I missed this part of the build. I am anxious and also want to build these as well as I can, so any input will be appreciated.

 

[avaserfi]

Just how important is the rock wool? I looked it up and it is VERY expensive and only available in somewhat large amounts. Is there a viable alternative? Will it make all of the difference in the sound quality of the speaker?

I am ready for glue up tomorrow and just realized that I missed this part of the build. I am anxious and also want to build these as well as I can, so any input will be appreciated.

I would not recommend use of this subwoofer without the rock wool. It serves the purpose of ensuring no mechanical noise from the driver is audible.

If you need some I would be able to ship enough for the subwoofer to you at the price I pay. I did the same for Haoleb as he had no local suppliers and did not need 6 whole sheets of it.

 

[avaserfi]

On another forum the issue of port resonance of such a design was raised. To properly address this issue I have measured the resonance of my build and related it to perceptual research involved with resonance audibility.

The full findings for those who are interested can be found here.

 

[Djizasse]

I don't understand those graphs :\ Care to offer a simple explanation?

Can the EP2500 run one of these subwoofers with just one channel? Do I have to run it bridged?
My idea was to power the sub with channel 1 and use channel 2 for tactile transducers.

 

[Haoleb]

Yes the EP2500 can run one sub per channel, As i am doing. However, run it bridged and you may not need those tactile transducers

 

[avaserfi]

I don't understand those graphs :\ Care to offer a simple explanation?

Can the EP2500 run one of these subwoofers with just one channel? Do I have to run it bridged?
My idea was to power the sub with channel 1 and use channel 2 for tactile transducers.

The basic issue was that some people thought the port resonance of such a design would be audible as it is far lower than typically found in commercial and DIY designs. To prove that the port resonance would not be audible I took 4 measurements of the subwoofer alone:

Maroon is the subwoofer measured from 1" with no crossover.
Blue is the subwoofer measured from 1" with a 4th order Linkwitz-Riley crossover at 80Hz.
Purple is the port measured from 1" from the opening with no crossover.
Green is the port measured from 1" from the opening with a 4th order Linkwitz-Riley crossover at 80Hz.

Note the peak in both port measurements at about 111Hz. This peak is the port resonance.

The conclusion of these measurements is that audibility of this peak when attenuated by a 4th order Linkwitz-Riley crossover at 80Hz is nonexistent as correlated with credible perceptual research and my own experience. Thusly, there is no need to worry about coloration due to port resonance in such a design.

 

[Djizasse]

Thanks for the explanation. So, it's totally useless to eliminate that resonance with an aggressive BP filter (at high Q)?

run it bridged and you may not need those tactile transducers

"Love Thy Neighbor"

 

[avaserfi]

Thanks for the explanation. So, it's totally useless to eliminate that resonance with an aggressive BP filter (at high Q)?

The point shown is that use of a 4th order L-R crossover at 80Hz is more than sufficient in attenuating port resonance at 110Hz and greater such that it is not audible. This is all that needs to be done.

Implementation of a more aggressive method of attenuation (via crossover or a notch filter) is not needed nor does the port need to be shortened to cause a higher initial port resonance as it is already a non-issue.