12" Infinity Kappa VQ Build Plans

[avaserfi]

She is alive!!!!

So I am sitting here with a huge sh** eating grin on my face. After having to wait and wait and wait to finish this sub due to school and work I finally managed to get it finished tonight.

Due to some time constraints I didn't have time to integrate the unit properly with my DCX so I just ran an RCA to 1/4" from my receiver to my EP2500 and fired the sucker up. The first question is how is the response and it seems very flat as I stuck it in the best natural place I have found in my room (it happens to be the center of the room). The second question is output. First off my room is about 8' deep x 18' wide x 8' tall (again with the sub nearly in the dead center). I put on my Rives test disc and put on the RS SPL calibrated tracks. sitting about 1.5 meters away I played the 20Hz test tone and sat diligently with the SPL in hand. The SPL registered 105 dB at the listening position with no audible distortion or compression and 99-100dB being placed 1 meter from the driver.

I could have gone louder as the Kappa was effortlessly reproducing these SPLs, but my windows were audibly flapping about and my entire floor felt unstable as it was actually wobbling like rubber (old wood floors) and I needed to catch my breathe . To be honest I am glad the cops didn't come as I bet my neighbors thought there was an earthquake or something.

This is one awesome driver no questions. I wouldn't hesitate to recommend the VQ to anyone for nearly any application due to its extreme versatility.

Pics to come later as well as response graphs when I have more time. For those who don't know the sub is fully functional, but has no veneer as that is going to happen when I work on the upper modules.

Lastly, a huge thanks to Chris for all his help.

 

[tomd51]

Great to hear, avaserfi! I've been following your thread as I considered using a 12" Kappa Perfect for a friend's sub build a few months ago, but I'd already had an Elemental Designs 13OV.2 onhand, so I opted for that driver instead. While I was pleased with it's results, of course I was left with the "what if?" question, not having an opportunity to try the Kappa.

Keep us posted on the veneers, definitely would like to see how this beast turns out.

Congrats! -TD

 

[no. 5]

The SPL registered 105 dB at the listening position with no audible distortion or compression and 99-100dB being placed 1 meter from the driver.

For what it's worth, it may have been a little louder than that; the calibration files that I have seen for the RS SPL meter show its response to be around 6dB down at 20Hz (unless you already compensated for that).

Either way, that a nice sub you have there.

 

[WmAx]

Well, avaserfi told me he desired a strong 20Hz extension when I was initially picking driver for optimal sound quality and desired extension. It would appear that he has achieved his desire. However, I was predicting 108 or dB for a single one of these subs in the cabinet I specified with the large cross section, large radius slot port I specified (all used in his final design) in room, near a re-enforcing wall. For him to get 105db in the middle of the room with no immediate boundary, and claiming he did not even push it to it's limits.... I guess I may have underestimated this driver's maximum output potential..... and at this point I will guess that he will achieve 115db at 20hz, if loaded in a corner and pushed to it's limit. To think he will later add a 2nd unit....

-Chris

 

[TLS Guy]

So I am sitting here with a huge sh** eating grin on my face. After having to wait and wait and wait to finish this sub due to school and work I finally managed to get it finished tonight.

Due to some time constraints I didn't have time to integrate the unit properly with my DCX so I just ran an RCA to 1/4" from my receiver to my EP2500 and fired the sucker up. The first question is how is the response and it seems very flat as I stuck it in the best natural place I have found in my room (it happens to be the center of the room). The second question is output. First off my room is about 8' deep x 18' wide x 8' tall (again with the sub nearly in the dead center). I put on my Rives test disc and put on the RS SPL calibrated tracks. sitting about 1.5 meters away I played the 20Hz test tone and sat diligently with the SPL in hand. The SPL registered 105 dB at the listening position with no audible distortion or compression and 99-100dB being placed 1 meter from the driver.

I could have gone louder as the Kappa was effortlessly reproducing these SPLs, but my windows were audibly flapping about and my entire floor felt unstable as it was actually wobbling like rubber (old wood floors) and I needed to catch my breathe . To be honest I am glad the cops didn't come as I bet my neighbors thought there was an earthquake or something.

This is one awesome driver no questions. I wouldn't hesitate to recommend the VQ to anyone for nearly any application due to its extreme versatility.

Pics to come later as well as response graphs when I have more time. For those who don't know the sub is fully functional, but has no veneer as that is going to happen when I work on the upper modules.

Lastly, a huge thanks to Chris for all his help.

That's a very impressive first test. Congratulations all round. I know exactly what you mean about the floor feeling unstable and being worried about the windows. I got really worried once as my floor started to look like clips from security cameras in an earthquake and had to kill it in a hurry. Since then I have been more circumspect.

 

[ParadigmDawg]

Awesome Andrew. I cant wait to hear it!

 

[avaserfi]

So, there is a little update to this situation. I decided to do a real max SPL test today with the sub corner loaded. Using my calibrated ECM8000 I set everything up in the listening position which is about 7-8 feet from the sub and cranked it up. At 20Hz there was 110dB at the listening position with no audible port compression or distortion from the driver. I actually ended up pussing out because my windows were actually bowing in and out considerably and I got worried about permanent damage to my apartment/the cops being called.


I think we can say I am happy with this sub . Sorry I don't have pics yet, but they will come I promise. I have been swamped with classes and am too lazy to get my camera out on a tripod.

 

[-knife fight-]

So i wasn't signed up to this site before and i was just watching this thread cause i was dying to see the final product so i had to sign up to say,Great work and post pics pics pics!!.

 

[annunaki]

Andrew,

I ran the Perfect VQ 12 in mid q mode through WinIsd and I was not that impressed to be honest. The response curve was nice, but the excursion was all out of wack????

I am thinking of selling my SVS PB-12 Ultra and doing a pair of these. After running it through WinIsd though I am not quite so sure. I am very intrigued by your findings.

What do you make of this anomaly?

 

[avaserfi]

Hmm, I haven't had any excursion issues. What was the cabinet size modeled as well as the tuning frequency port size etc? I found that WinISD did not do a good job with its auto adjust of the Kappa VQ, but after toying with the settings for a while it modeled very well.

My 3.5 cubic foot cabinet with a 55"x12.5"x3" port models well (20hz tune).

The latest pics (remember veneer will be applied when the entire speaker system is complete):

The rounds are fully non-functional so the gaps don't effect performance in the least. Before applying veneer the gaps will be filled with something like Bondo for aesthetic purposes.

Edit: Here is how the driver models for me Transfer function first then Excursion second. You can see the port sizing, tuning frequency and box sizing on the right.

 

[WmAx]

Andrew,

I ran the Perfect VQ 12 in mid q mode through WinIsd and I was not that impressed to be honest. The response curve was nice, but the excursion was all out of wack????

I am thinking of selling my SVS PB-12 Ultra and doing a pair of these. After running it through WinIsd though I am not quite so sure. I am very intrigued by your findings.

What do you make of this anomaly?

As Andrew has provided, the excursion curve at full rated power is acceptable, in the specific tuned systems that I specified, that Andrew used in his final design. It should be noted that the Kappa Perfect subwoofers have an extremely conservative x-max rating, or so it would seem. At x-max, they are linear. I have pushed Kappa Perfects 50 percent past the rated x-max without obvious detriment, unlike most drivers, that become obviously distorted before approaching x-max rating, much less exceeding it. In actual use, I find it unlikely that one would ever approach rated x-max in a normal size room for real program material(as opposed to test tones pushed to maximum SPL), if using the cabinet system that Andrew uses. I a not sure what kind of motor design that Infinity used - but I suspect it is one that is extraordinarily linear to a point - then becomes extremely non linear without gradual degradation, possibly operating at a critical failure point when it is pushed to that point. I know that I have read about failures that seem to meet this description on car audio forums concerning the Kappa Perfect drivers. The typical description of failure reads something like this: no obvious problems - driving extremely hard - then sudden mechanical failure ensues. To be fair, I am not aware of these drivers ever being marketed for SPL applications - though they obviously can produce substantial SPL with very low distortion - but perhaps it is not that safe to abuse them on purpose as would a typical teen ager trying to impress his peers with his car stereo's 'boom boom' ability.

-Chris

 

[annunaki]

The excursion peaks at about .866 inches which is xmax plus 35%. That seems a bit out of standard operating range.

For now I will most likely be selling my SVS PB-12 Ultra and doing an enclosure for my 12W7 tuned to 18hz-20hz. With the proceeds of the sale, I will pick up a Behringer EP2500 and DCX2496 and or a feedback destroyer. I will be trying it out sealed at first and then going vented afterwards.

I am thinking I may be quite happy with that option.

 

[avaserfi]

The excursion peaks at about .866 inches which is xmax plus 35%. That seems a bit out of standard operating range.

By my model xmax is 18.3mm while rated xmax is 16.75mm which results in an excursion 10% greater than rated at maximum rated power (400W) which would be rarely achieved.

Also, from the measurements I have seen on this driver over at Home Theater Shack, taken by Ikka, there is no reason to be concerned with the small deviance from rated xmax.

The math:

18.3-16.75 = 1.55

100*(1.55/16.75) = 9.25%

For now I will most likely be selling my SVS PB-12 Ultra and doing an enclosure for my 12W7 tuned to 18hz-20hz. With the proceeds of the sale, I will pick up a Behringer EP2500 and DCX2496 and or a feedback destroyer. I will be trying it out sealed at first and then going vented afterwards.

I am thinking I may be quite happy with that option.

You seem to like those drivers. I look forward to seeing your build progress.

 

[WmAx]

The excursion peaks at about .866 inches which is xmax plus 35%. That seems a bit out of standard operating range.

For now I will most likely be selling my SVS PB-12 Ultra and doing an enclosure for my 12W7 tuned to 18hz-20hz. With the proceeds of the sale, I will pick up a Behringer EP2500 and DCX2496 and or a feedback destroyer. I will be trying it out sealed at first and then going vented afterwards.

I am thinking I may be quite happy with that option.

It would appear that you did not model the same alignment as avaserfi used. The excursion peaks at far less, and in a narrow band. Considering the very conservative x-max specification and the very high SPL range this occurs - it is a non issue. I carefully selected this driver after careful modeling considerations before suggesting it to avaserfi for his specific desired application(best value high output, very low distortion driver to be used to at least 20Hz) that will outperform most high-end retail units. As for performance, avaserfi has already measured very high SPL from a single one of these units; 110db at 20Hz at listening position with no sign of audible distortion, and he did not push it to limit because he is in an apartment. I would wager that if you compare this to the sealed JL Audio 13" home unit, that the Fathom will not be able to compare below 30Hz in terms in of SPL vs. distortion. Of course, the JL is crippled, being used in a sealed box and having it's low end extension enabled by EQ. If you put that same driver in the appropriate ported or passive radiator system, of course, it would out perform the Kappa Perfect driver in maximum SPL vs. distortion in all frequency ranges.

Why would you buy a feedback destroyer and a DCX? That is redundant; the DCX has parametric band filters.

BTW, is that JL Audio a 3 ohm (two 1.5 ohm coils in series) driver? If so, the EP2500 will probably have reduced power output in bridged mode - as the current demands will rise above what was intended for it's minimum 4 ohm rated bridged output. In 3rd party tests, output was greatly reduced at 2.4 ohms bridged(only about 1200 watts, compared to 2000 at 4.4 ohms), supporting this probable outcome.

-Chris

 

[annunaki]

By my model xmax is 18.3mm while rated xmax is 16.75mm which results in an excursion 10% greater than rated at maximum rated power (400W) which would be rarely achieved.

Also, from the measurements I have seen on this driver over at Home Theater Shack, taken by Ikka, there is no reason to be concerned with the small deviance from rated xmax.

The math:

18.3-16.75 = 1.55

100*(1.55/16.75) = 9.25%




You seem to like those drivers. I look forward to seeing your build progress.

My bad. It was late for me when I posted sorry about the mixup.

 

[annunaki]

It would appear that you did not model the same alignment as avaserfi used. The excursion peaks at far less, and in a narrow band. Considering the very conservative x-max specification and the very high SPL range this occurs - it is a non issue. I carefully selected this driver after careful modeling considerations before suggesting it to avaserfi for his specific desired application(best value high output, very low distortion driver to be used to at least 20Hz) that will outperform most high-end retail units. As for performance, avaserfi has already measured very high SPL from a single one of these units; 110db at 20Hz at listening position with no sign of audible distortion, and he did not push it to limit because he is in an apartment. I would wager that if you compare this to the sealed JL Audio 13" home unit, that the Fathom will not be able to compare below 30Hz in terms in of SPL vs. distortion. Of course, the JL is crippled, being used in a sealed box and having it's low end extension enabled by EQ. If you put that same driver in the appropriate ported or passive radiator system, of course, it would out perform the Kappa Perfect driver in maximum SPL vs. distortion in all frequency ranges.

Why would you buy a feedback destroyer and a DCX? That is redundant; the DCX has parametric band filters.

BTW, is that JL Audio a 3 ohm (two 1.5 ohm coils in series) driver? If so, the EP2500 will probably have reduced power output in bridged mode - as the current demands will rise above what was intended for it's minimum 4 ohm rated bridged output. In 3rd party tests, output was greatly reduced at 2.4 ohms bridged(only about 1200 watts, compared to 2000 at 4.4 ohms), supporting this probable outcome.

-Chris

I will most likely do the DCX, as was my original plan. I will be doing the W7 in a vented enclosure tuned to 20hz. It is big though. The vent alone displaces about 1.8 cu.ft. It will not be much bigger than my SVS PB-12 Ultra, but should crush it in every way. I am afraid it is going to be a massively heavy enclosure at 7.37 cu.ft. gross before any displacement calculations. I have it 80% designed right now. I just need to finalize the bracing and then figure all of my cuts.

Once I am all set to go, I will put my SVS up for sale. If I can get $800.00 for it, it will easily cover my whole project.

I only need 750 watts rms from the Behringer. From my calculations I will not be able to stand it at full rated power. As long as it will give me 3db of headroom from full rated power (on the sub) I will be fine with it. i.e. 1,500 watts rms. The sub is a single 3 ohm coil.

 

[WmAx]

I will most likely do the DCX, as was my original plan. I will be doing the W7 in a vented enclosure tuned to 20hz. It is big though. The vent alone displaces about 1.8 cu.ft. It will not be much bigger than my SVS PB-12 Ultra, but should crush it in every way. I am afraid it is going to be a massively heavy enclosure at 7.37 cu.ft. gross before any displacement calculations. I have it 80% designed right now. I just need to finalize the bracing and then figure all of my cuts.

Once I am all set to go, I will put my SVS up for sale. If I can get $800.00 for it, it will easily cover my whole project.

I only need 750 watts rms from the Behringer. From my calculations I will not be able to stand it at full rated power. As long as it will give me 3db of headroom from full rated power (on the sub) I will be fine with it. i.e. 1,500 watts rms. The sub is a single 3 ohm coil.

Never, in my life, have I built a single sub. Always pairs. I guess it's partially by obsessive compulsive behavior. But you know, you should just build two of those darn things. Would not 125 dB at 20Hz be a rational goal?

In any case, for safety purposes of the amplifier, it would be best if you use just one channel of the EP2500 for each subwoofer. This will give you about 850-900 watts output into 3 ohms - of course - peak output is higher for very short millisecond durations, as with any amplifier. You will get a little more power bridged, I would estimate 1300-1500 watts, based on the known measured behaviors from credible 3rd parties. But you do risk the unit running at excessive heat levels if you use it at moderate to high levels on a regular basis into 3 ohms bridged; the amplifier simply was not intended to operate into a load under 4 ohms when bridged. I have run amplifiers under their rated impedances for long periods of time - but it's always a risk in the long term.

-Chris

 

[annunaki]

If I am happy with the W7, I will find another sub and build another enclosure. I want dual subs as well.

 

[Djizasse]

The pics are gone. Can you do something about it?
It would be nice to compile all this into a word document, zip it and upload it.

 

[Haoleb]

Heres a link to andrews photobucket with the pics.

http://s288.photobucket.com/albums/ll171/avaserfi/My 12 MidQ Build/