# Infinity Kappa 120.9w box graphs



## sannitig (Aug 23, 2013)

Hey Guys,

Could someone please look at the graphs on this sub and explain the difference between sealed and ported results?

http://eu.infinitysystems.com/tl_fi...a/Kappa/9-Series/120.9w/KAPPA120-9w_PI_EN.pdf

I'm trying to decide which route I want to go and do not have the luxury of hearing the sub in the two different boxes.

Thank you so much.

One sub run off a Pioneer gm-d9601


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## sqshoestring (Jun 19, 2007)

The graphs show in car response, which is based on whatever car they tested. The dashed line is the real box response. In my car there is little cabin gain so the sealed would not get low it would hit hard about 40hz and up like SPL. I ran an older Infinity 12 and it did just that, then I ran quad IB 12s and also did that until I put a PEQ on them. The ported would go lower and have more bottom. Depends on the car you have. Even the in car you can see a 5db peak at 40hz while the ported is more flat from 40 and on down. Of course also depends on what response you want. Personally I would do ported and tune it a little lower yet but I like a deep bottom and hate bumps at 40hz and up...and my current car has little gain to help. Some cars will fill the bottom end in for you.

Aside from cabin gain of your car, when you look at a chart anything over 2-3db is a change you will hear, 5 certainly, 10 forget it it will be difficult to EQ that without a lot of power and a healthy sub.


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## ATOMICTECH62 (Jan 24, 2009)

I was just playing around with this sub on BBP6 and once again I get a longer port then Infinity suggest for the fb.
They say-4"@13-5/8" long=30hz in 2cuft
I get-4"@20" long=30hz in 2cuft

Their port length=35hz in 2cuft.

What gives?
Dont want to jack this thread but it might make a difference to the OP.


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## therapture (Jan 31, 2013)

sannitig said:


> Hey Guys,
> 
> Could someone please look at the graphs on this sub and explain the difference between sealed and ported results?
> 
> ...



Well, you have enough power. I run my 120.9w sealed, and it plays nicely into the low ranges considering cabin gain and being fed an honest 500w of power available. If you are EQ'ing that sub/running active, then you should be golden, even sealed.

It's a nice sub, doesn't require much EQ in my car, and has the excursion to play deep with a fair amount of power applied.


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## sannitig (Aug 23, 2013)

I'm not running an equalizer but I am running 500w to it. This was supposed to be a budget system and turned out to be $2000 with install...

What about the eq and x-over in the deck?? Would that help if I went sealed?

Pioneer DEH-X9500BHS

The only reason I ask for assistance with the box is because I'm driving down to the USA from Canada to pick it up. I want to make sure I'm making the right decision from going all that way. I wanted to sound great and musical and I've read that sealed versus ported does not always mean sound quality versus SPL. That's the only reason I'm even considering ported, if I can gain loudness as keep the sq, then why not do ported.


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## sannitig (Aug 23, 2013)

ATOMICTECH62 said:


> I was just playing around with this sub on BBP6 and once again I get a longer port then Infinity suggest for the fb.
> They say-4"@13-5/8" long=30hz in 2cuft
> I get-4"@20" long=30hz in 2cuft
> 
> ...


That's interesting, I will have to keep that in mind if that's the case.


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## sannitig (Aug 23, 2013)

sqshoestring said:


> The graphs show in car response, which is based on whatever car they tested. The dashed line is the real box response. In my car there is little cabin gain so the sealed would not get low it would hit hard about 40hz and up like SPL. I ran an older Infinity 12 and it did just that, then I ran quad IB 12s and also did that until I put a PEQ on them. The ported would go lower and have more bottom. Depends on the car you have. Even the in car you can see a 5db peak at 40hz while the ported is more flat from 40 and on down. Of course also depends on what response you want. Personally I would do ported and tune it a little lower yet but I like a deep bottom and hate bumps at 40hz and up...and my current car has little gain to help. Some cars will fill the bottom end in for you.
> 
> Aside from cabin gain of your car, when you look at a chart anything over 2-3db is a change you will hear, 5 certainly, 10 forget it it will be difficult to EQ that without a lot of power and a healthy sub.


Thanks


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## sannitig (Aug 23, 2013)

So the graphs state "included driver displacement". 

Trying to wrap my head around this. Does this mean to get 1 cu. ft. I need a smaller box or a bigger box like 1.25cu ft?


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## therapture (Jan 31, 2013)

sannitig said:


> So the graphs state "included driver displacement".
> 
> Trying to wrap my head around this. Does this mean to get 1 cu. ft. I need a smaller box or a bigger box like 1.25cu ft?


I think a typical 12" is about .08 to .1 ft³ displacement....so you would want to build your box to 1.1ft³ if you wanted it just about 1.0ft³ net, but with sealed, that small a change will be a non-issue.

I personally like a bit bigger sealed, I run mine in 1.44ft³ after driver displacement. With this sub, it gets me a box "Q" of .724 (.707 is "ideal" in many circles). With only 1ft³ that gets a Q of .800 which still isn't bad.

I really like this sub.


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## sannitig (Aug 23, 2013)

therapture said:


> I think a typical 12" is about .08 to .1 ft³ displacement....so you would want to build your box to 1.1ft³ if you wanted it just about 1.0ft³ net, but with sealed, that small a change will be a non-issue.
> 
> I personally like a bit bigger sealed, I run mine in 1.44ft³ after driver displacement. With this sub, it gets me a box "Q" of .724 (.707 is "ideal" in many circles). With only 1ft³ that gets a Q of .800 which still isn't bad.
> 
> I really like this sub.


Ah crap. I ended up getting a 1cu ft box from sonic electronics lined with Polly fill. I can still buy a 1.25 or a 1.5. Cu ft as I'm not picking up until next week


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## sannitig (Aug 23, 2013)

So I'm thinking I might build my own ported box using those plastic tubes.

Probably going to to tune around 30Hz. I'm curious to see how this sub will perform in a ported box over my little sealed box. It thumps as it is right now but I do have to turn it way up to make it do so, to the point where the music (highs) hurt my ears, I think porting will make it louder. Then when I turn it up where the music hurt my ears, the sub will be REALLY powerful!

Only thing that concerns me now is sub sonic freq. Will the sub get damaged if it plays music below 30Hz?


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## 14642 (May 19, 2008)

Those are my enclosure design sheets. I tried to make it simple, but I guess that didn't work. It means, build the box volume that's indicated. if it indicates that the box should be 1 cubic foot, build a 1 cubic foot box. Line it with an inch thick fiberglass insulation or dacron.

And for shoestring, the in car graph is a real graph. It's based on the average of about 30 cars' transfer functions. 

I model boxes in LEAP. If you are using a simpler program or not factoring in the damping material, you may get different results.


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## therapture (Jan 31, 2013)

So Andy, what do you think of that particular subwoofer? I really like mine, but what do I know?


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## sannitig (Aug 23, 2013)

I listened to some rock the other day on it and damn...that's where it shines, my goodness...clean clear bass.

My electro dance music though...it sounds good but it's not NEARLY powerful enough.

I sat in my friends car...type R sub in ported box...sounds like crap but is loud!!!

I want mine but I want it louder!!! I will try ported but if that doesn't work I will probably get another 120.9W, two is better than one right?


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## sqshoestring (Jun 19, 2007)

Andy Wehmeyer said:


> Those are my enclosure design sheets. I tried to make it simple, but I guess that didn't work. It means, build the box volume that's indicated. if it indicates that the box should be 1 cubic foot, build a 1 cubic foot box. Line it with an inch thick fiberglass insulation or dacron.
> 
> And for shoestring, the in car graph is a real graph. It's based on the average of about 30 cars' transfer functions.
> 
> I model boxes in LEAP. If you are using a simpler program or not factoring in the damping material, you may get different results.


Thanks Andy, always wondered where they got the information from. I think I had 1252w and they had a similar graph. IMO it was accurate, I just like a much deeper sound and that car didn't help any. I still have the subs, thought about running a PEQ on them and doing ported or IB HT in the house some day. The quad 12s IB (about 16cf I guess) had a lot of impact, quite a bit of deep output on only 420rms with the PEQ. Raw signal the 40-50hz just ruled and not my taste. Unfortunately quads actually sat the rear of that car lower lol.


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## therapture (Jan 31, 2013)

sannitig said:


> I listened to some rock the other day on it and damn...that's where it shines, my goodness...clean clear bass.
> 
> My electro dance music though...it sounds good but it's not NEARLY powerful enough.
> 
> ...


I listen to ALOT of "electronic", such as Delerium, Astrix, Electric Universe, 1200 Mics, Cosmic Gate, Zedd, Infected Mushroom, Ocean Lab, Pretty Lights, Protoculture, plus ****loads of stuff I don't even remember the name of...

...and this sub plays it with aplomb. What kind of real power are you feeding the sub? What car are you running this in and where is the sub located? Of course I am running my sub active, crossed at 75hz/24db, and it is tuned to a curve via my DSP...so that would change things a bit since I can make the power go where I want it.


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## ZAKOH (Nov 26, 2010)

This subwoofer is well suited for a 1-1.25cu ft (net) sealed box. When you set impedance switch to 4ohm, ~1.2cu ft is for the perfect qtc. When you set the impedance to 2ohm, then box software suggests 1.7cu ft for 0.707 qtc. However, the qtc does not increase a lot if you put it into a 1-1.2cu ft box. I have run it both ways, as 2ohm and 4ohm sub, in a 1.15cu ft (gross) sealed box stuffed with some polyfill. I power it with a 600watt RMS amplifier in 4ohm mode. It can handle power IMHO. At least I haven't blown mine yet.

As for ported, I have no idea. The manual claims that this is a "medium q" design well suited either for sealed or ported box. The ported box will give you more output and probably a hump in the lowest frequencies, but you will give up more trunk space to it.


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## ZAKOH (Nov 26, 2010)

Andy Wehmeyer said:


> Those are my enclosure design sheets. I tried to make it simple, but I guess that didn't work. It means, build the box volume that's indicated. if it indicates that the box should be 1 cubic foot, build a 1 cubic foot box. Line it with an inch thick fiberglass insulation or dacron.


Andy, can you explain how this subwoofer maintains the same inductance value (according to the manual) in both 2ohm and 4ohm mode? I heard that inductance follows the same laws as resistance when you change the wiring of the voice coil from series to parallel, so inductance is supposed to change when you flip the impedance switch on the subwoofer, shouldn't it?


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## therapture (Jan 31, 2013)

ZAKOH said:


> This subwoofer is well suited for a 1-1.25cu ft (net) sealed box. When you set impedance switch to 4ohm, ~1.2cu ft is for the perfect qtc. When you set the impedance to 2ohm, then box software suggests 1.7cu ft for 0.707 qtc. However, the qtc does not increase a lot if you put it into a 1-1.2cu ft box. I have run it both ways, as 2ohm and 4ohm sub, in a 1.15cu ft (gross) sealed box stuffed with some polyfill. I power it with a 600watt RMS amplifier in 4ohm mode. It can handle power IMHO. At least I haven't blown mine yet.
> 
> As for ported, I have no idea. The manual claims that this is a "medium q" design well suited either for sealed or ported box. The ported box will give you more output and probably a hump in the lowest frequencies, but you will give up more trunk space to it.


I run mine on 2ohms, and I made the box to fit the spare well, so it came out to 1.44 ft³ net, stuffed @1.5lbs. I doubt I could tell a difference by filling it down to 1.2.

Sounds great, even before the tuning.


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## sannitig (Aug 23, 2013)

If anyone is still subscribed...

I'm now running at 2 ohms, 800w and what a difference. Still have the 1 cu ft box from soniceletronix.

Would like to build a ported box but not sure what to tune the port to. I read that playing through the subs FS sounds bad so it would have to be above 27Hz correct?


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## therapture (Jan 31, 2013)

I have recently retuned mine a bit. Currently using 75hz/48db linkwitz (thx hanatsu!) and I was able to give it +2db from 20-25 hz and fatten up the bottom end. I have modeled it ported, 28hz in 2ft of space would be sweeeeeeeet,but it also looks like it would be too much low end and required me to just have to eq out the peak. With 800w I doubt you really need ported, a nice eq could distribute that power where you want it?


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## sqshoestring (Jun 19, 2007)

Tune the port low as you need the box to play, just remember you lose output the lower you go. It will be easier to get lower with a larger box, shorter port too. It might not take as much power if you use a large box (in the normal range you would use for a given sub).


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## cajunner (Apr 13, 2007)

therapture said:


> I have recently retuned mine a bit. Currently using 75hz/48db linkwitz (thx hanatsu!) and I was able to give it +2db from 20-25 hz and fatten up the bottom end. I have modeled it ported, 28hz in 2ft of space would be sweeeeeeeet,but it also looks like it would be too much low end and required me to just have to eq out the peak. With 800w I doubt you really need ported, a nice eq could distribute that power where you want it?


if you need that output, the 3 db of boost by way of a ported box gain, is there for the taking.

equalizing a mild hump and redistributing those bass watts is the free lunch in car audio, and who doesn't like a nice, greasy, sloppy free lunch?


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## hurrication (Dec 19, 2011)

I just acquired one of these and have been thinking about running it in a transmission line with 200 watts. After testing it in 2 and 4 ohm mode, it seems like the inductance stays close to a 1:1 ratio to the re in 4 ohm mode despite what it says in the manual. It measures close to advertised specs, but in 4 ohm the re/le is 4.14/3.25 and 2 ohm is 1.85/1.92. Looking at the impedance plot, the rate of inductive roll off past minima is less in 2 ohm mode and qts is also little lower than 4 ohm mode.

Anyone ran this sub at both impedances in the same enclosure and noticed a difference in performance? I was going to run mine at 4, but it seems that 2 might have a slight advantage... so curious if getting an amp to run it at 2 would be worth it.


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## 14642 (May 19, 2008)

ZAKOH said:


> Andy, can you explain how this subwoofer maintains the same inductance value (according to the manual) in both 2ohm and 4ohm mode? I heard that inductance follows the same laws as resistance when you change the wiring of the voice coil from series to parallel, so inductance is supposed to change when you flip the impedance switch on the subwoofer, shouldn't it?


The inductance doesn't stay the same, but the frequency response does. That happens because the rolloff at high frequencies is determined by the inductance AND the resistance and they both change when you flip the switch. Same goes for Qes. Motor force is (BL^2)/Revc. When the coils are in series, L is increased and so is Revc. When the coils are in parallel, L is decreased and so is Revc.


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## cajunner (Apr 13, 2007)

hurrication said:


> I just acquired one of these and have been thinking about running it in a transmission line with 200 watts. After testing it in 2 and 4 ohm mode, it seems like the inductance stays close to a 1:1 ratio to the re in 4 ohm mode despite what it says in the manual. It measures close to advertised specs, but in 4 ohm the re/le is 4.14/3.25 and 2 ohm is 1.85/1.92. Looking at the impedance plot, the rate of inductive roll off past minima is less in 2 ohm mode and qts is also little lower than 4 ohm mode.
> 
> Anyone ran this sub at both impedances in the same enclosure and noticed a difference in performance? I was going to run mine at 4, but it seems that 2 might have a slight advantage... so curious if getting an amp to run it at 2 would be worth it.


interesting.

from Andy's input, it looks to me that you'd have more motor force with the series config, and if you want more output and only have 200 watts, you'd be better off running in 4 ohm mode.

I'm wondering, if you double the re from 2 ohm at 1.85, why doesn't it add up to 4.14 of the 4 ohm measurement?

Is it additional resistance from passing through several contact points of a switch or is there more turns on one of the coils?


3.70 to 4.14 is quite a bit of additional resistance?


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## hurrication (Dec 19, 2011)

cajunner said:


> interesting.
> 
> from Andy's input, it looks to me that you'd have more motor force with the series config, and if you want more output and only have 200 watts, you'd be better off running in 4 ohm mode.
> 
> ...


From what I understand, this sub uses a triple voice coil so the numbers won't be divisible the same way a dvc sub would be.

The qes of mine in 4 ohms is .729 which yields a bl^2/re of 66, while in 2 ohm mode the qes is .667 with a bl^2/re of 78.


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## 14642 (May 19, 2008)

There's no way the Qes is .7 and .6. Mayve you're thinking of Qtc. Anyway, this woofer doesn't scale perfectly like 2-ohm and 4-ohm DVCs because this thing is three coils in a couple of configurations depending on the switch position. I can't remember exactly. You can read the patent. Just search Jason Wehner at the USPTO.


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## cajunner (Apr 13, 2007)

did not know that they used 3 coils on the motor joy, that's a new one for me.

thanks for the clarification, Mr. Wehmeyer.


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## hurrication (Dec 19, 2011)

Andy Wehmeyer said:


> There's no way the Qes is .7 and .6. Mayve you're thinking of Qtc. Anyway, this woofer doesn't scale perfectly like 2-ohm and 4-ohm DVCs because this thing is three coils in a couple of configurations depending on the switch position. I can't remember exactly. You can read the patent. Just search Jason Wehner at the USPTO.


By no means am I trying to be controversial, simply stating my results.

Sub was tested firmly mounted with the cone firing horizontally, 1/2 surround method, with 230g mmd which yields as close to the listed 237g mms as possible with the software. Test ran multiple times on each impedance to confirm repeatability.

4 ohm:









2 ohm:


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## sannitig (Aug 23, 2013)

hurrication said:


> I just acquired one of these and have been thinking about running it in a transmission line with 200 watts. After testing it in 2 and 4 ohm mode, it seems like the inductance stays close to a 1:1 ratio to the re in 4 ohm mode despite what it says in the manual. It measures close to advertised specs, but in 4 ohm the re/le is 4.14/3.25 and 2 ohm is 1.85/1.92. Looking at the impedance plot, the rate of inductive roll off past minima is less in 2 ohm mode and qts is also little lower than 4 ohm mode.
> 
> Anyone ran this sub at both impedances in the same enclosure and noticed a difference in performance? I was going to run mine at 4, but it seems that 2 might have a slight advantage... so curious if getting an amp to run it at 2 would be worth it.


I did. I ran at 4 ohms for the longest time and just swittched to 2 ohms and it made a world of difference.

Next is going to be porting time! What does it mean when people say "it sounds awful when playing through the tuning frequency?"

I was planning on tuning around 28Hz.


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## 14642 (May 19, 2008)

hurrication said:


> By no means am I trying to be controversial, simply stating my results.
> 
> Sub was tested firmly mounted with the cone firing horizontally, 1/2 surround method, with 230g mmd which yields as close to the listed 237g mms as possible with the software. Test ran multiple times on each impedance to confirm repeatability.
> 
> ...


Interesting. If I were still at Harman, I'd investigate. I wonder if there's an engineer left who would...


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## AAAAAAA (Oct 5, 2007)

^What happened over there anyways? No more car audio division?


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## 14642 (May 19, 2008)

There's still a division for car audio. Actually, they are quite focused on it. I have no idea what they are planning, though.


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## rton20s (Feb 14, 2011)

Andy Wehmeyer said:


> There's still a division for car audio. Actually, they are quite focused on it. I have no idea what they are planning, though.


You act like you're busy with something else?! 

Aren't we all supposed to keep tabs on the inner workings of our former employers?


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## LNA71 (Feb 13, 2015)

Hello all. I'm hoping Mr. Wehmeyer might still be around to answer a quick question.

In the spec sheet found at

fi.infinityspeakers.com/tl_files/catalog//Infinity/Infinity-Car/Specsheets/Kappa/Kappa/9-Series/120.9w/KAPPA120-9w_PI_EN.pdf

it shows a graph entitled "Sealed Enclosure (Frequency Response @ 2.83V)."

The left side of the graph has a scale for 2 ohms and the right side has a scale for 4 ohms. There is a 3 dB difference between the two scales.

My amplifier is regulated. It outputs 500 W RMS to both 2 ohm and 4 ohm loads. Resistance does not matter, it puts out the same power.

Since the subwoofer gets 500 W RMS either way from this amp, will the 2 ohm configuration still be 3 dB higher in output?

I'm thinking the graph is assuming the power from an amp doubles when the resistance is reduced from 4 ohms to 2 ohms, but I'm not sure.

Thanks in advance.


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## therapture (Jan 31, 2013)

I have the 120.9 and a regulated Alpine pdx v9 amp. 2 or 4, I cannot hear a dfference. Power is power, and a 3db bump would mean twice the power, not something my amp can do. And I doubt going from 2 to 4 would change the sensitivity so much.

So why would they show that? I bet Andy has an answer to that somewhere.


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## LNA71 (Feb 13, 2015)

I think you are right. I have the PDX-V9 as well.


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## LNA71 (Feb 13, 2015)

hurrication said:


> By no means am I trying to be controversial, simply stating my results.
> 
> Sub was tested firmly mounted with the cone firing horizontally, 1/2 surround method, with 230g mmd which yields as close to the listed 237g mms as possible with the software. Test ran multiple times on each impedance to confirm repeatability.
> 
> ...





Andy Wehmeyer said:


> Interesting. If I were still at Harman, I'd investigate. I wonder if there's an engineer left who would...


Looks like BL is higher when running the subwoofer at 4 ohms. This is confirmed in the manual for the subwoofer. Does this mean the motor will have more control at 4 ohms than at 2 ohms? Will the sensitivity be the same or not? Is the graph assuming a doubling of power?

Just trying to understand any differences in the subwoofer between 2 ohm and 4 ohm operation with the same amount of power supplied.

Harman customer service has not been helpful. I think the people there with real knowledge don't answer customer service questions, unfortunately. When I asked about the graph a few weeks ago in an email, they sent back an answer that didn't address what I was asking. Not even close. When I replied and stated such, they asked what I wanted to know. I again sent the same question, and haven't heard back now in some time.


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## LNA71 (Feb 13, 2015)

I got a response from Harman tech support finally. Here is what they said.

"I am very sorry to see that no one has responded to your request. I’ve just received this and will do whatever I can to help you. If you have already resolved your issue or inquiry, please ignore this email. If you have not yet resolved it, please accept my most sincere apology, and now I will try to assist you.

This is a great question. The answer is no, the speaker will not play any louder, regardless of the impedance setting. The graph was created using one amplifier and switching between the two impedances. This amp happened to double in power, and so the speaker put out a hotter signal. In your case, it will not do this. Your best bet is to run the speaker at 4 ohms so that the amp sees a 4 ohm load and runs cooler, with less distortion."


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## BassShark12 (Apr 2, 2015)

Hey everyone, I'm new to this site and would love to have anyone's help regarding the Kappa 120.9w as I am looking to make a purchase for 2 myself (even though they are a few years old because then I'd have Kappas all around [= ). 

I've been trying to find whether or not 1000 Watt RMS from an amp would be too much for two of them since they are rated to 350 Watts each and lots of places/ people I've spoken with are telling me yes. 
Then I notice that LNA71, you're using 500 for just the one right?? Should I stay safe and use a lower rated amp like 600-800 for the two or can I just go with 1000 Watt RMS and be fine as long as the gains are set perfectly? 
The amp I would be interested in using is the Rockford Fosgate P1000x2, meaning I'd be wiring them in series to get the 1000 Watts @ 4-ohm.

Rockford Fosgate Punch P1000X2 2-channel car amplifier — 300 watts RMS x 2 at Crutchfield.com

If anyone and everyone is willing to pitch their thoughts, I'd sincerely appreciate it!!!!


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## ATOMICTECH62 (Jan 24, 2009)

As long as your gains are set correctly you will be fine.But if you drive the amp into hard clipping for extended periods of time you could damage them.
Other things like box size and tuning frequencies can have a major factor in power handling.


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## therapture (Jan 31, 2013)

This sub handles my V9 with aplomb - 500 clean watts to these subs, each, would be great. 

I find these are good SQL subs - they are not meant to pound at full excursion all day, but they WILL play nasty if you need them too. I find that driving them a little bit under "max output" results in fantastic SQ and definition - and they blend well into my front stage.


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## BassShark12 (Apr 2, 2015)

ATOMICTECH62 said:


> As long as your gains are set correctly you will be fine.But if you drive the amp into hard clipping for extended periods of time you could damage them.
> Other things like box size and tuning frequencies can have a major factor in power handling.


Yea, I am definitely not looking to be cranking the volume at max every time I get in the car. The amplifier I will be using from Rockford pretty much sets itself to the proper gain using clipping LEDs available on the amp (which is awesome). the remote bass knob that works for this amp has the clip LED too so I can see whats going on from the front seat if need be lol 





therapture said:


> This sub handles my V9 with aplomb - 500 clean watts to these subs, each, would be great.
> 
> I find these are good SQL subs - they are not meant to pound at full excursion all day, but they WILL play nasty if you need them too. I find that driving them a little bit under "max output" results in fantastic SQ and definition - and they blend well into my front stage.


I'll be honest, I don't know what you meant by V9 with Aplomb butttt it sounds like 1000 Watts (at a maximum) should be fine..? 
Just a little nervous because this will be my first subwoofer set up and I'd rather not twist anything up :3


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## therapture (Jan 31, 2013)

PDX- V9 is my alpine amp that can push a bit over 500w to the sub. Aplomb is a good thing.


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## BassShark12 (Apr 2, 2015)

That looks pretty awesome for the car/1sub set up that's for sure! I'm still new to this whole thing, and kind of the reason why I'm inclined to use rockford for the amplifier; I didn't want to "do it by ear?" and end up over setting/under setting the gain and risk screwing something up. Though I could stop being a wuss and use something from Alpine xD haha


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## Rzzza (Sep 19, 2017)

therapture said:


> Well, you have enough power. I run my 120.9w sealed, and it plays nicely into the low ranges considering cabin gain and being fed an honest 500w of power available. If you are EQ'ing that sub/running active, then you should be golden, even sealed.
> 
> It's a nice sub, doesn't require much EQ in my car, and has the excursion to play deep with a fair amount of power applied.


I hate to dig up an old thread but it's relevant to my situation and you still seem to be active in the forums so, I'd like to ask your opinion on building an enclosure for the Kappa 120.9s. 
I have two of these and I want to build a sealed enclosure. I found this thread while searching for a 1.0 vs 1.4 cubic ft enclosures. I have them in single 1cu ft prefabbed enclosures now. (atrend)
I have to determine the amount of volume inside the enclosure, I don't understand the speaker displacement though, so I would need to know dummy dimensions.


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## rton20s (Feb 14, 2011)

Rzzza said:


> I hate to dig up an old thread but it's relevant to my situation and you still seem to be active in the forums so, I'd like to ask your opinion on building an enclosure for the Kappa 120.9s.
> I have two of these and I want to build a sealed enclosure. I found this thread while searching for a 1.0 vs 1.4 cubic ft enclosures. I have them in single 1cu ft prefabbed enclosures now. (atrend)
> I have to determine the amount of volume inside the enclosure, I don't understand the speaker displacement though, so I would need to know dummy dimensions.


If your enclosure is a simple rectangle multiply the internal length x width x height in inches and divide by 1728. That will give you the total internal volume of the enclosure. One nice thing about the enclosure design specs from Harman (JBL/Infinity) in that era is that they are pretty spot on for optimal performance. You can thank Andy Wehmeyer for that. Their recommended sealed enclosure for the 120.9W (1CF per driver) includes the driver displacement. So, if you build an enclosure that is 1728 cubic inches (1CF) per driver, you should be good to go. 

A little larger won't hurt. 1.5CF per driver or larger, and you might want to model the driver response and excursion with the power available from your selected amplifier.


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## Rzzza (Sep 19, 2017)

rton20s said:


> If your enclosure is a simple rectangle multiply the internal length x width x height in inches and divide by 1728. That will give you the total internal volume of the enclosure. One nice thing about the enclosure design specs from Harman (JBL/Infinity) in that era is that they are pretty spot on for optimal performance. You can thank Andy Wehmeyer for that. Their recommended sealed enclosure for the 120.9W (1CF per driver) includes the driver displacement. So, if you build an enclosure that is 1728 cubic inches (1CF) per driver, you should be good to go.
> 
> A little larger won't hurt. 1.5CF per driver or larger, and you might want to model the driver response and excursion with the power available from your selected amplifier.


Thanks very much, I didn't know anyone replied to this. I currently have two of them in two single enclosure each are 1cu ft but I I am thinking about building them a nicer box that holds both. Can you explain what I might notice if I decided to go less volume than recommended? I really want some trunk space back, I was thinking about 28x10x14 with 1" wood which is 1.44 cubic ft. for both subs. Do you know of any pros and cons that I might notice? Thanks


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## rton20s (Feb 14, 2011)

Rzzza said:


> Thanks very much, I didn't know anyone replied to this. I currently have two of them in two single enclosure each are 1cu ft but I I am thinking about building them a nicer box that holds both. Can you explain what I might notice if I decided to go less volume than recommended? I really want some trunk space back, I was thinking about 28x10x14 with 1" wood which is 1.44 cubic ft. for both subs. Do you know of any pros and cons that I might notice? Thanks


I personally would try to keep the box larger, if possible. Even considering cabin gain, you're likely to lose output on the bottom end with the smaller enclosure. Lack of extension, if you will, compared to the enclosures you are currently using. The smaller enclosures may feel a bit "punchier in the upper bass/midbass region as well.


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## DeltaB (Jun 17, 2017)

The specs from Harmon for each cabinet is the total volume after driver displacement.


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## rton20s (Feb 14, 2011)

DeltaB said:


> The specs from Harmon for each cabinet is the total volume after driver displacement.


The manual states: *SEALED-BOX VOLUME (INCLUDES DRIVER DISPLACEMENT)*

That would seem to indicate that the recommended enclosure volume (1.0CF) does not require you to construct a larger box to account for displacement. Displacement for the driver is likely somewhere around 0.6 - 0.7CF. Either way, I would opt for the largest enclosure you are comfortable using and can fit in your install.


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## PPI_GUY (Dec 20, 2007)

A few in this thread have demonstrated (thru practical real-time application) that a larger enclosure yields a better result with this driver. Specifically, 1.4-1.5 cu. ft. 
Personally, I plan to run mine sealed in approx. 1.5 cu. ft gross (before driver install) for each subwoofer with resistance set at 2 ohms. 
Need to read the entire thread to have a better grasp of what seems to work better with this sub.


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## DeltaB (Jun 17, 2017)

rton20s said:


> The manual states: *SEALED-BOX VOLUME (INCLUDES DRIVER DISPLACEMENT)*
> 
> That would seem to indicate that the recommended enclosure volume (1.0CF) does not require you to construct a larger box to account for displacement. Displacement for the driver is likely somewhere around 0.6 - 0.7CF. Either way, I would opt for the largest enclosure you are comfortable using and can fit in your install.


I've worked with a number of JBL and Infinity drivers, in fact, I use an 8" Infinity in my installation.

You are welcome to email their tech department, they'll tell you the same. General rule of thumb, add this to your enclosure size to get the desired size;

8 inch = 0.03 ft3 
10 inch = 0.05 ft3 
12 inch = 0.07 ft3 
15 inch = 0.10 ft3

So for the sealed enclosure you would add 0.07. You would seek a sealed enclosure of roughly 1.1 cubic feet, or exactly 1.07CF, minus the displacement to get you to 1.0 if you mount externally. Larger baskets and magnet structures obviously displace more room.


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## rton20s (Feb 14, 2011)

DeltaB said:


> I've worked with a number of JBL and Infinity drivers, in fact, I use an 8" Infinity in my installation.
> 
> You are welcome to email their tech department, they'll tell you the same. General rule of thumb, add this to your enclosure size to get the desired size;
> 
> ...


I don't really need to email their tech department. I could PM Andy directly, or just look back on page one of this thread...



Andy Wehmeyer said:


> Those are my enclosure design sheets. I tried to make it simple, but I guess that didn't work. It means, build the box volume that's indicated. if it indicates that the box should be 1 cubic foot, build a 1 cubic foot box. Line it with an inch thick fiberglass insulation or dacron.
> 
> And for shoestring, the in car graph is a real graph. It's based on the average of about 30 cars' transfer functions.
> 
> I model boxes in LEAP. If you are using a simpler program or not factoring in the damping material, you may get different results.


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## DeltaB (Jun 17, 2017)

rton20s said:


> I don't really need to email their tech department. I could PM Andy directly, or just look back on page one of this thread...


What they are telling you simply, is that when the speaker is inside the enclosure, you need to have 1.0CF. To do that you need to have a cabinet that is 1.0CF + driver displacement. You build the box 1.07, drop the driver in which will take out 0.07CF of space and leave you with 1.0CF of space. If you're using a competition woofer with a huge frame and magnet structure, refer to the manufacturer for the actual displacement volume of the woofer. It isn't rocket surgery.


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## rton20s (Feb 14, 2011)

DeltaB said:


> What they are telling you simply, is that when the speaker is inside the enclosure, you need to have 1.0CF. To do that you need to have a cabinet that is 1.0CF + driver displacement. You build the box 1.07, drop the driver in which will take out 0.07CF of space and leave you with 1.0CF of space. If you're using a competition woofer with a huge frame and magnet structure, refer to the manufacturer for the actual displacement volume of the woofer. It isn't rocket surgery.














Andy Wehmeyer said:


> *Those are my enclosure design sheets.* I tried to make it simple, but I guess that didn't work. It means, build the box volume that's indicated.* if it indicates that the box should be 1 cubic foot, build a 1 cubic foot box.* Line it with an inch thick fiberglass insulation or dacron.


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## rton20s (Feb 14, 2011)




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## DeltaB (Jun 17, 2017)

rton20s said:


>


Andy doesn't work for Harmon. You can contact Harmon support, and they will tell you what I have. How do I know? 2 guesses and the 1st doesn't count. It isn't brain science. You asked, I told you. If you don't like my answer, ask the people who actually made it. Have a great day.


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## rton20s (Feb 14, 2011)

DeltaB said:


> Andy doesn't work for Harmon. You can contact Harmon support, and they will tell you what I have. How do I know? 2 guesses and the 1st doesn't count. It isn't brain science. You asked, I told you. If you don't like my answer, ask the people who actually made it. Have a great day.


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## SkizeR (Apr 19, 2011)

DeltaB said:


> Andy doesn't work for Harmon. You can contact Harmon support, and they will tell you what I have. How do I know? 2 guesses and the 1st doesn't count. It isn't brain science. You asked, I told you. If you don't like my answer, ask the people who actually made it. Have a great day.


actually, at the time of his post, he did. 

or at least just left


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## DeltaB (Jun 17, 2017)

rton20s said:


>


Thanks for the info


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## Weightless (May 5, 2005)

Lolz

Sent from my SM-N920P using Tapatalk


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## DeltaB (Jun 17, 2017)

SkizeR said:


> actually, at the time of his post, he did.
> 
> or at least just left


Actually, it doesn't have anything to do with the question. If you have a set of parameters that includes displacement, you have to remove that displacement to get the actual size. If the set of parameters didn't include the displacement, and you claim it does, then the question is erroneous. It's just that simple.


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## rton20s (Feb 14, 2011)




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## PPI_GUY (Dec 20, 2007)

therapture said:


> I think a typical 12" is about .08 to .1 ft³ displacement....so you would want to build your box to 1.1ft³ if you wanted it just about 1.0ft³ net, but with sealed, that small a change will be a non-issue.
> 
> I personally like a bit bigger sealed, *I run mine in 1.44ft³ after driver displacement. With this sub, it gets me a box "Q" of .724 (.707 is "ideal" in many circles). With only 1ft³ that gets a Q of .800 which still isn't bad.*
> 
> I really like this sub.


The above is from an actual, real world user of this driver. Quoted for reference.


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## DeltaB (Jun 17, 2017)

PPI_GUY said:


> The above is from an actual, real world user of this driver. Quoted for reference.


I run a Reference 860W and 0.35 is specified (includes displacement) for sealed design, and the 0.40 enclosure works very well for me after driver displacement brings it back down to about 0.36 (also, in the lower corner where the engineer who makes the graph generally attributes his initials isn't Andy's)


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## rton20s (Feb 14, 2011)

DeltaB said:


> I run a Reference 860W and 0.35 is specified (includes displacement) for sealed design, and the 0.40 enclosure works very well for me after driver displacement brings it back down to about 0.36 (also, in the lower corner where the engineer who makes the graph generally attributes his initials isn't Andy's)


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## DeltaB (Jun 17, 2017)

Might go easy on them pliers on them teeth, they don't grow back yunno...


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## rton20s (Feb 14, 2011)

DeltaB said:


> Might go easy on them pliers on them teeth, they don't grow back yunno...


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## DeltaB (Jun 17, 2017)

rton20s said:


>


Now, take the sealed enclosure reference response and superimpose the 8 10 and 12" on top of each other. Tell me how many drivers of various size in various enclosures make exactly the same plot. (the inside backstage tattling of consumer product divisions from Chinese suppliers)


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## rton20s (Feb 14, 2011)

DeltaB said:


> Now, take the sealed enclosure reference response and superimpose the 8 10 and 12" on top of each other. Tell me how many drivers of various size in various enclosures make exactly the same plot. (the inside backstage tattling of consumer product divisions from Chinese suppliers)


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## therapture (Jan 31, 2013)

PPI_GUY said:


> The above is from an actual, real world user of this driver. Quoted for reference.



It's pretty simply, not sure why there was an argument going on lol.

This driver works very well in an SQL application, plays lower and more efficiently in a bigger than spec box.


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