Sealed Infinity Kappa Perfect VQ

[Guiria]

You can see that the amp is really clipping hard when they try to use the EQ to boost output. Folks: you must use VERY high powered amps when you try to boost LF output on a sealed system. That was not a well done EQ compensation system by any means, nor did the DIYer have a clue of the requirements of power for the application.

-Chris

And this is the reason small sealed subs like Sunfires have 2500 watts rms (or whatever it is)...to boost the low end, I've never figured that out before. People always ramble about how sealed subs need more power but they never specifically say WHY they need more power.

Assuming a sealed box:
Why wouldn't you get a kappa perfect 12DVQ and wire it in parallel and run 1200 watts @ 2 ohm load per channel from the EP2500? Doesn't it claim that kind of power handling...

 

[WmAx]

And this is the reason small sealed subs like Sunfires have 2500 watts rms (or whatever it is)...to boost the low end, I've never figured that out before. People always ramble about how sealed subs need more power but they never specifically say WHY they need more power.

Assuming a sealed box:
Why wouldn't you get a kappa perfect 12DVQ and wire it in parallel and run 1200 watts @ 2 ohm load per channel from the EP2500? Doesn't it claim that kind of power handling...

The EP2500 can be bridged to drive 4 ohms mono, outputting a real 2000 watts of clean power. Assuming you have a dedicated 20A line to the Behringer with very large guage wire on a short run from the breaker box. As such, you can use the single VC version to the same end.

Except unless minimum size is needed, I don't see why sealed should be used. One can get much more LF output, and with lower power, out of the ported alignments that have been suggested.

-Chris

 

[Guiria]

The EP2500 can be bridged to drive 4 ohms mono, outputting a real 2000 watts of clean power. Assuming you have a dedicated 20A line to the Behringer with very large guage wire on a short run from the breaker box. As such, you can use the single VC version to the same end.

Except unless minimum size is needed, I don't see why sealed should be used. One can get much more LF output, and with lower power, out of the ported alignments that have been suggested.

-Chris

All the reading I've done on the kappa perfect involve SPL vs. Distortion. How does this sub sound? Is it tight? Ported or not, I don't care, I'm on the fence at this point.

I'd like to hear peoples impressions on SQ for this sub.

Perhaps I've missed all that in previous threads but I have read several regarding the kappa perfect and nothing comes to mind regarding SQ.

 

[WmAx]

All the reading I've done on the kappa perfect involve SPL vs. Distortion. How does this sub sound? Is it tight? Ported or not, I don't care, I'm on the fence at this point.

I'd like to hear peoples impressions on SQ for this sub.

Perhaps I've missed all that in previous threads but I have read several regarding the kappa perfect and nothing comes to mind regarding SQ.

The reason I do not make subjective statements about SQ issues, is because this subwoofer is transparent. It has distortion below audible limits. It's sound is completely and utterly the result of the cabinet you install it in. The cabinet will define it's sound. You can use a powerful precise DSP device like a DCX2496 to manipulate it's sound further, since this device can precisely change the response curve to your preference(s). It all comes down to: if you build a carefully thought out/designed cabinet - it will sound great. If you build a poor cabinet, it will sound bad.

-Chris

 

[Guiria]

Using the DCX2496 does placement of the subwoofers become less critical?

Also, are their any downsides to porting out the front instead of the rear like Avaserfi's build?

I'm trying to conceptualize how 2 5^3 ft boxes in my multi-purpose room would work, and perhaps if I laid them down on their side I could blend them in better. They would be up against a wall, however, and so front porting would be optimal.

 

[mike c]

Using the DCX2496 does placement of the subwoofers become less critical?

Also, are their any downsides to porting out the front instead of the rear like Avaserfi's build?

I'm trying to conceptualize how 2 5^3 ft boxes in my multi-purpose room would work, and perhaps if I laid them down on their side I could blend them in better. They would be up against a wall, however, and so front porting would be optimal.

no. basically you go through these in order of priority:
1) find the best position for your sub and listening position
2) room treatments
3) EQ

EQ that tailors the sound or FR on a DIY sub is another matter.

port location is irrelevant as long as air movement is not hampered.
though usually, locating the port up front = more SPL.

 

[annunaki]

no. basically you go through these in order of priority:
1) find the best position for your sub and listening position
2) room treatments
3) EQ

EQ that tailors the sound or FR on a DIY sub is another matter.

port location is irrelevant as long as air movement is not hampered.
though usually, locating the port up front = more SPL.

With the port on the same plane as the woofer, the waves are more evenly time-aligned/coupled which can result in potentially slightly higher output.

 

[Alex2507]

With the port on the same plane as the woofer, the waves are more evenly time-aligned/coupled which can result in potentially slightly higher output.

Port on the same plane means what exactly? Like a front firing sub with a port on the front? or does it mean that the centers of each line up on a horizontal plane?

 

[annunaki]

It would mean that with a front firing driver, the port opening would be on the front as well.

 

[Guiria]

Anyone have an educated guess or real world experience on the Kappa Perfect vs. the Dayton HF 12" in a sealed alignment?

I showed my wife Avaserfi's sub build and her jaw dropped, I'm not sure she is sold on the whole "we may never have to upgrade subs again" line I was using

 

[WmAx]

Anyone have an educated guess or real world experience on the Kappa Perfect vs. the Dayton HF 12" in a sealed alignment?

I showed my wife Avaserfi's sub build and her jaw dropped, I'm not sure she is sold on the whole "we may never have to upgrade subs again" line I was using

Sorry, I know of no credible 3rd party measurements that were made in the proper fashion of the Dayton that could be compared to the Kappa Perfect measurements. It would be a risk, in my view, to go with the Dayton. The Kappa Perfect is of known, quantified performance(which is very high).

-Chris

 

[TLS Guy]

Anyone have an educated guess or real world experience on the Kappa Perfect vs. the Dayton HF 12" in a sealed alignment?

I showed my wife Avaserfi's sub build and her jaw dropped, I'm not sure she is sold on the whole "we may never have to upgrade subs again" line I was using

What does your wife know about it?

The lowest F3 possible with that driver, and it has to be in a sealed box, is 42.74 Hz. It exceeds xmax with its rated power at just below 30 Hz, so EQ would limit spl severely. It does achieve an spl of 112 db though.

Not nearly as good as the kappa perfect 12 VQ.

If you build the kappa sealed subs, which will be fine for your requirements, I don't see that you would need to buy more drivers. If your circumstances change you might want to build ported enclosures for the drivers.

 

[WmAx]

What does your wife know about it?

The lowest F3 possible with that driver, and it has to be in a sealed box, is 42.74 Hz. It exceeds xmax with its rated power at just below 30 Hz, so EQ would limit spl severely. It does achieve an spl of 112 db though.

112 dB 'on paper'. Not many drivers can actually come near their theoretical maximums, of course; at least not without severe mechanical noises/distortion, etc.

-Chris

 

[TLS Guy]

112 dB 'on paper'. Not many drivers can actually come near their theoretical maximums, of course; at least not without severe mechanical noises/distortion, etc.

-Chris

I agree in "theory". The lowest F3 is in a box 1.6 cu.ft. If you lower the box size to around 1 cu.ft. then the f3 comes up to around 46 Hz but there are no xmax issues at its rated power. This is a driver designed to go in a small box, and be thrown in a vehicle, to make lots of noise, with no regard to quality.

 

[Guiria]

Thanks for your inputs. given the known performance of the kappa, I would definitely buy it over the dayton, and the kappa can be had on ebay for about 180 shipped with warranty. That's about $50 for piece of mind knowing what I'm getting into.

 

[Guiria]

After re-reading this thread I have a few more questions.

TLS Guy posts a recommended box volume of net 1.25 with no insert meaning a low-Q alignment.
WmAx posts a recommended box size of 16" cubed yielding roughly a 2^3 ft with the driver using a mid-Q alignment.

Are we talking two different boxes here or basically the same box explained differently? It seems I'm getting two recommendations which opens up a whole new can of worms on which box design I should use...

Will this sub perform acceptably without the DSP modified frequency response from the DCX2496 or is that piece of equipment critical for this configuration? I do plan on buying a BFD, however since I do not use external amplifiers for my mains the DCX wouldn't be utilized at this point.

Thanks in advance.

 

[TLS Guy]

After re-reading this thread I have a few more questions.

TLS Guy posts a recommended box volume of net 1.25 with no insert meaning a low-Q alignment.
WmAx posts a recommended box size of 16" cubed yielding roughly a 2^3 ft with the driver using a mid-Q alignment.

Are we talking two different boxes here or basically the same box explained differently? It seems I'm getting two recommendations which opens up a whole new can of worms on which box design I should use...

Will this sub perform acceptably without the DSP modified frequency response from the DCX2496 or is that piece of equipment critical for this configuration? I do plan on buying a BFD, however since I do not use external amplifiers for my mains the DCX wouldn't be utilized at this point.

Thanks in advance.

I'm sorry, but you are mixed up. The no insert is a HIGH Qt driver. You need a high Qt for the best sealed alignments.

Now you said you had shared walls and did not want to annoy the neighbors, and you were not interested in high spl. At least that was the gist of you pm to me.

The sealed enclosure and the vented boxes are very different designs.

Please look at this post carefully, which shows all my alignments for the kappa perfect 12 VQ.

http://forums.audioholics.com/forums/showpost.php?p=412993&postcount=5

The first is 1.25 cu.ft sealed with an F3 around 32 Hz. Now this will roll off at 12 db per octave and so will be about 15 db down at 16 Hz. So for your purposes it will be fine even if you do not use Eq. You can Eq a sealed sub, and if you start to add 12db per octave Eq at around 30 Hz you can flatten the response to 20 Hz and below. However it will take more amp power. Double the power for every 3db boost at that frequency.

Now the next alignment is low insert with a ported enclosure using a tube vent. Flippo built this and has been pleased with it.

The third alignment is for the low Qt insert with slot vent.

The fourth is the mid Qt insert in a ported enclosure with slot vent. The technical graphs and simulations are all there, so take your pick.

Now WmAx did a 3cu.ft alignment. This lowers F3 to 28 Hz. This is using no insert. xmax is not exceeded. It is up to you to decide whether this increase in size justifies the reduction in F3. I chose the smaller box as I thought if someone wanted to use a sealed alignment they would want to take advantage of a smaller box size. At 3 cu. ft. you can have a ported box with the low insert.

You asked me if the sealed alignment would be satisfactory for your needs, as you described them the answer is still, Yes.

I hope this clears up your confusion.

Here is the 3 cu. ft. sealed. If you want a completer pdf. PM me and I will Email a complete pdf.

Driver Properties
Name: Kappa Perfect 12 VQ
Type: Standard one-way driver
Company: Infinity Systems Inc.
No. of Drivers = 1
Fs = 22.9 Hz
Qms = 10.29
Vas = 96.43 liters
Cms = 0.323 mm/N
Mms = 176.4 g
Rms = 2.398 kg/s
Xmax = 16.75 mm
Xmech = 25.13 mm
P-Dia = 250 mm
Sd = 491 sq.cm
P-Vd = 0.822 liters
Qes = 0.79
Re = 4.42 ohms
Le = 1.14 mH
Z = 4 ohms
BL = 11.92 Tm
Pe = 400 watts
Qts = 0.74
no = 0.141 %
1-W SPL = 83.65 dB
2.83-V SPL = 89 dB
-----------------------------------------
Box Properties
Name:
Type: Closed Box
Shape: Prism, square
Vb = 3 cu.ft
Qtc = 0.821
QL = 20
F3 = 28.05 Hz
Fill = heavy

 

[Guiria]

I'm sorry, but you are mixed up. The no insert is a HIGH Qt driver. You need a high Qt for the best sealed alignments.

Thanks for clearing that up.

Now don't you want to stick around a Qtc of .70-.75? If so what would the cubic feet requirement be?

The 1.25 box has a Qtc of 1.003 and the 3.0 box has a Qtc of .81 so that looks like a sealed box would need to be bigger than 3^3 ft to achieve the desired Qtc?

I may as well go ported if that is the case.

How will the sound of a sealed box with a Qtc of 1 differ from that of a box with Qtc of .75???

 

[TLS Guy]

Thanks for clearing that up.

Now don't you want to stick around a Qtc of .70-.75? If so what would the cubic feet requirement be?

The 1.25 box has a Qtc of 1.003 and the 3.0 box has a Qtc of .81 so that looks like a sealed box would need to be bigger than 3^3 ft to achieve the desired Qtc?

I may as well go ported if that is the case.

How will the sound of a sealed box with a Qtc of 1 differ from that of a box with Qtc of .75???

The Qtc of the 1.25 cu.ft enclosure is around 1.0 which is just acceptable. The sealed enclosures have less phase shift and time delay and I think it will have good SQ. If you want you can add 1 cu. ft which will get the Qtc to 0.85 and the F3 to 29. But for a sealed enclosure, I think the sound will sound pretty tight either way. None of these designs have specs that are out of bounds.

I don't know your space available and WAF factors. Really you have a lot of leeway with the sealed enclosure, it can be from 1.25 to 3 cu.ft. Remember smaller enclosures are easier to brace and less prone to enclosure coloration. That is one advantage of smaller enclosures.

It's time to choose and get building.

 

[Guiria]

Does the EP2500 have enough power to apply the boost around 30 Hz and not introduce large amounts of distortion or risk of damaging either driver or amp?