Sub install

[LCP]

Some pics of the install, just a 10" Infinity Kappa Perfect 10.1D, sound's good, much better than when it was in a sealed box in my other car.The boot:

Close up of the sub and amp:

Before the rear seat was fitted:

Finished... not visible under normal lighting.

LCP

 

[LCP]

Oops, typo error, should be "infinite baffle"...

 

[weechoon]

LCP,
where did u install this ?...looks interesting & save some space at the boot !

 

[Vanquish]

LCP,

Has the boot been soundproofed / treated ? You'll be surprised at the amount of openings /gaps in the E36 boot that cud rob you of low bass notes. Just curious ..

Cheers bro,

 

[dwj]

wow....cool...looks not bad ..save alot of space.how was the quality?good?
how much it cost btw?

 

[LCP]

Install was done at CT2 here up north at Bayan Baru, Penang... total cost of install including amp and HU install was only RM170, all these items had been taken out of my other car a week earlier. Amp wiring is already there on my E36. A baffle chip-board was needed to mount the sub, 1/2" thickness.

And nope, no extra soundproofing other than stock stuff... the nice thing about this sub is that it is capable of much lower freq than others, refer to specs attached below... No missing low notes yet, at least not to my ears, low bass is pretty full, like I mentioned, much better than when it was in sealed box. Will play my test CD one of these days, it includes a "warble" track at 80Hz mid point, warbling between 40Hz and 120Hz to ensure smooth transition between sub and my speakers.

My sub low pass filter cut-off freq is set at 80Hz, 4th order (-24db/octave) and the normal speakers are set to high pass filter at the same freq point, 4th order too, all set from my HU... Alpine CDA-9833.

Attached below is the spec and frequency response of the sub in a recommended small 0.6 cu ft sealed case. Also shown below is the infinite baffle response of the older and single coil variant of this sub (Kappa Perfect 10).

Specifications of Infinity Kappa Perfect 10.1D...

Sealed case response, 0.6 cu ft only!

This is the infinite baffle response of the older and single coil model:

LCP

 

[DanPromote]

nice and simple! I've also installed mine without the box but located in the top-middle part of the rear speakers. Had problems with vibrations to the top speaker panel but after adding some padding it was better. Still I noticed a loss on lower range.. maybe it's due to the standard single core 12in sub. (shuttlelab). Will try to get something like yours to compensate.

Btw where are u located, anywhere nearby PJ/KL? Would love to hear a demo of your sub at one of the tt sessions.

Here's how mine looks :-

 

[LCP]

Hi DanPromote,

I'm located in Penang... The sub must be capable of being used in infinite baffle applications, usually the instruction manual or marketing brochure will state so. Mine's stated in the instruction manual but user was cautioned about the max power handling, which is estimated to be just half than when in sealed/ported case, this is to avoid the coil from moving out of the magnet range due to too much excursion, infinite baffle has nothing to damp the movement of the cone, unlike in sealed case.

The total Q factor is the basic guideline to determine the case type to the sub, usually for infinite baffle, Q factor must be high, I can't remember how much, maybe above 0.6. If going by the Q factor alone, my sub is supposed to be more at home with a sealed case or even a ported case.

LCP

 

[SMG330i]

To get a max perfomance for this configuration, we need a freeair sub. Normal sub if install to this config, eventually it'll not get the best quality. Lost of low freq will occurs and we won't get tat kick anymore. If we go for freeair sub, we will be getting much of the same quality with the sealed ones.

 

[Iqlima]

I always curious about what range of my ear can hear.I did a test today and found I can only hear sound from 25hz up to 15Khz but my wife can hear up to 17Khz ( no surprise ). In normal life there is alot noise out there which "disturb" our ear try to catch extreme frequency while driving a car.

May be you can try download from internet ( there is a lot sound test) and see whether your ear can tell different between frequency ( well make sure speaker capable produce it ) before you start spend more money on nothing.....

Cheers

nice and simple! I've also installed mine without the box but located in the top-middle part of the rear speakers. Had problems with vibrations to the top speaker panel but after adding some padding it was better. Still I noticed a loss on lower range.. maybe it's due to the standard single core 12in sub. (shuttlelab). Will try to get something like yours to compensate.

Btw where are u located, anywhere nearby PJ/KL? Would love to hear a demo of your sub at one of the tt sessions.

 

[Daniel]

LCP, you do seem to be knowledgeable in the techical aspects for car audio, so why did you even allow such an install in your car?

This 'free-air' mounting of a vertical amp rack behind the rear sear, is so amaturish. Since being about to explain the finer details of your crossover cut-offs, frequencies etc, somewhere along that road you would have realised that that install isn't going to work wonders.

 

[Daniel]

Have freeair subs come such a long way over the past few years?

Free air subs are supposed to use the boot as their enclosure arn't they? er..... how sealed is that? I can tell you, leaks everywhere!

If you need good bass, better an enclosure custom built for your sub.

There is a reason why rep show cars and award winning cars have their subs and sometimes their speakers in individual enclosures, and aesthetics is only half of it.

To get a max perfomance for this configuration, we need a freeair sub. Normal sub if install to this config, eventually it'll not get the best quality. Lost of low freq will occurs and we won't get tat kick anymore. If we go for freeair sub, we will be getting much of the same quality with the sealed ones.

 

[SMG330i]

Daniel : I totally agree with you, it's still long way for freeair subs to catch up, but for our fellow members config, better way is to buy a freeair sub. If you listen to music soft, and dun need all that punch, a/d/s freeair sub is surely a good choice. Last, enclosure still rocks. haha.

 

[Iqlima]

LCP like the sound, I think he's pro on his own !

Basic theory says, isolate front side and rear side of speaker because like mirror but different direction,so it will cancel each other. Speaker need air to work.

Infinite baffle system normally need large enclosure compare to air suspension system where need small enclosure.

Anyway, car environment never good to create such very low frequency, it need large amount of air.

But some people just want to feel the low frequency rather than to hear it. Saliva drop when their butt shake !

Cheers

LCP, you do seem to be knowledgeable in the techical aspects for car audio, so why did you even allow such an install in your car?

This 'free-air' mounting of a vertical amp rack behind the rear sear, is so amaturish. Since being about to explain the finer details of your crossover cut-offs, frequencies etc, somewhere along that road you would have realised that that install isn't going to work wonders.

 

[Daniel]

can you please explain this further?

Basic theory says, isolate front side and rear side of speaker because like mirror but different direction,so it will cancel each other.

are you implying that you have 2 speakers mounted one infront of the other out of phase from each other?er.....why are you bring that up? no correlation la.

 

[Daniel]

ever notice if your entire speaker panel is flexing when you crank it up?

nice and simple! I've also installed mine without the box but located in the top-middle part of the rear speakers. Had problems with vibrations to the top speaker panel but after adding some padding it was better. Still I noticed a loss on lower range.. maybe it's due to the standard single core 12in sub. (shuttlelab). Will try to get something like yours to compensate.

Btw where are u located, anywhere nearby PJ/KL? Would love to hear a demo of your sub at one of the tt sessions.

Here's how mine looks :-

http://www.xtmods.com/images/bmwspeaker.jpg

 

[LCP]

Yo Daniel... yes I know there are leaks, but I don't think it is affecting the bass that I'm getting. Simple explanation here... the leaks are not at the "correct" locations to cause major cancellation of certain frequencies. Just like when you design a ported enclosure, if the port is designed wrongly, you will get poor efficiency, and possible cancellation. But if it is designed correctly, the output of the port is actually in phase and will reinforce the sound.

There is also an explanation for the possible good bass in my setup... the subwoofer itself. Although this is not a true freeair sub, it already has some capability, albeit at some lower power levels as advised by the manufacturer. The sub is designed to have very very low Vas (compliance volume), which means that if you put it in a case bigger than the Vas volume, it will perform as if it is mounted infinite baffle. In my sub, the Vas is just 1.095cu.ft. (31 litres), this is already smaller than most people's sealed enclosure! So, right now, with a boot of maybe 300-400 litres, it is definitely a whole lot more infinite than the minimum spec, and little leaks should not be affecting the sound.

Btw, there are only 3 noticeable "leaks" between the boot and the interior:
1) The ventilation grille near the 3rd brake light housing.
2) The rear speakers... with 5.25" speakers, there's some gap in the opening, taken care by polyester fibrefill paddings...

LCP

 

[LCP]

DanPromote, just had a good look again at your setup... from the photo, it looks like there's insufficient separation between the front and rear of your sub... the sub looks like it's firing part of the sound into the boot. I think that should explain the low freq cancellation.

LCP

 

[LCP]

Iqlima, most humans can actually hear 20Hz, the only problem is not many speakers can reproduce that low note correctly. Most of the time, you will end up feeling the 20Hz moving air instead of hearing it. In my car, using my test CD, I can actually hear the 20Hz, but on my home hi-fi, I can only feel the moving air. If you are using a good pair of headphones to listen to the 20Hz, I think you should be able to hear it.

The "feeling" that you get when you hear a 20Hz note is actually very similar to the feeling you get when you are near a bunch of elephants... heck, elephants communicate using infra-sound frequencies anyway... 20Hz and below.

Or maybe it's just me being a bit weird to be able to hear so low.... hahaha...

LCP

 

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