# LF ported box built



## eviling (Apr 14, 2010)

I want a nice ported box preferer formed into my trunk. I Wang quality box though I really am not looking to an excessive system its a simple sub and amp that'll be going in. 2 8" image dynamic IDv3 and a helix B2. WANNA do ported just to maximise the output 
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## subwoofery (Nov 9, 2008)

What's your question? lol

Kelvin


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## eviling (Apr 14, 2010)

subwoofery said:


> What's your question? lol
> 
> Kelvin


I want a ported box done in my car. I don't understand the conffusion seemed pretty cut and dry to me :\ 

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## subwoofery (Nov 9, 2008)

eviling said:


> I want a ported box done in my car. I don't understand the conffusion seemed pretty cut and dry to me :\
> 
> Sent from my EVO using Tapatalk 2


You want a sub formed into your trunk... Do you need fiberglassing advice on that? Do you need ideas on where to put the port? 
So it's gonna be a ported enclosure... Do you need us to model an enclosure for you? For SQ, SQL? Tuning freq you'd prefer? 

Reason I asked what your question really was 

Kelvin


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## eviling (Apr 14, 2010)

it says lf ported box built in tittle. i'm sorry if i confused ya


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## subwoofery (Nov 9, 2008)

cajunner said:


> I think he wants someone to build one for him.


Oups... Sorry, did not notice that we were in the "car audio jobs" sub-forum :blush: 

Kelvin


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## eviling (Apr 14, 2010)

i believe ive seen you talk of boxes in the past, perhaps you could be of some assitance, im half considering doiing it my self i just guidence. i built sealed boxes and recently built a very very large one that i was quite happy with 

the subs are speced for the subs are 2 8" Image Dyanic IDv3 sub's

http://www.sonicelectronix.com/item_22182_Image-Dynamics-ID8-D4-V.3.html

Subwoofer Series	ID V.3
Subwoofer Size	8"
Peak Power Handling	300 watts
RMS Power Handling	150 watts
Voice Coil(s)	Dual
Impedance (Per Voice Coil)	4 ohms
Sensitivity	85.6 dB
Xmax (millimeters)	15.5 mm
Subwoofer Design	Round / Circle
Main Cone Color	Black
Woofer Composition	Poly-Mica
Woofer Surround	Rubber
Subwoofer Grille	No
Re-Cone Kit Available	No
Recommended Enclosure Specifications
Recommended Enclosure Type	Ported / Vented
Sealed
Minimum Sealed Box Volume	.20 cubic feet
Maximum Sealed Box Volume	0.45 cubic feet
Minimum Ported Box Volume	0.50 cubic feet
Maximum Ported Box Volume	0.90 cubic feet
Top-Mount Depth	4-3/4"
Cutout Diameter	7-1/8"


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## subwoofery (Nov 9, 2008)

What type of car and will you be using a PEQ to lower any peak in the low frequencies region or only a subsonic filter? 

Kelvin


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## eviling (Apr 14, 2010)

stock nav has 9 band EQ no subsonic but amp might. its helix B2 percisian , ima look into that. doenst look like it though. 

im considering an ms-8 or processor of the like sort.

its a sedan, 09 impala.


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## Oliver (Jun 25, 2007)

12vdb.com - car audio database: Image Dynamics Id8v3.1 - YouTube



> Chaos` 8 ID8D4v.3 in a 1.5 cu. ft. dual tuned (ABC) enclosure at 28Hz and 56Hz, powered by a Parts Express 250. He`s playing the Speakerboxxx Intro from Outkast. The ID8 being motivated to maximum excursion in a custom slot ported dual tuned bass reflex enclosure.


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## subwoofery (Nov 9, 2008)

eviling said:


> stock nav has 9 band EQ no subsonic but amp might. its helix B2 percisian , ima look into that. doenst look like it though.
> 
> im considering an ms-8 or processor of the like sort.
> 
> its a sedan, 09 impala.


After modelling, I like 1.3cuft tuned to 27Hz - a 4" round port makes the vent 33" long. 
Transfer function -3dB is around 40Hz which should mate well with the cabin gain of your sedan... 
With your B2, use the highpass to the lowest setting (15Hz) - if you use an MS-8, use 20Hz @ 6dB/oct slope 

If you get creative, you might not lose much trunk space - a design such as this one: 









Kelvin


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## eviling (Apr 14, 2010)

yeah... so if its a round hole why you showing me a vented port not a tube? O_O and thats a jl box lol i don't follow the info your giving me, so a 4" round hole in each champer 30" long but only 1.4 CF how the ****


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## subwoofery (Nov 9, 2008)

eviling said:


> yeah... so if its a round hole why you showing me a vented port not a tube? O_O and thats a jl box lol i don't follow the info your giving me, so a 4" round hole in each champer 30" long but only 1.4 CF how the ****


Ok, let's try something else... 

Look at the below picture: 








Your 2 x ID8 in that kind of box with the vent above your subs like in the first picture I've linked. 

ID8 have a mounting depth of 4.75" so if you build the vent to be 5.75" x 2.5" - length of the port becomes 37.57" in order to keep the tuning freq @ 27Hz in a 1.3cuft box

Kelvin


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## subwoofery (Nov 9, 2008)

cajunner said:


> I wouldn't tune any 8" car audio subwoofer to 27 hz, that just seems sadistic to me.
> 
> By the time you get up an octave to 54 hz, you're moving away from the protective excursion control the vent provides and losing output in the region of the power response most suited for music.
> 
> ...


All good points... Just did not see much problem since the ID8 has an FS of 22.7Hz  
Input signal of 360 watts, the apparent load @ the amp is only 200 watts so it's not straining the amp much IMO - and tuning higher, the amp is actually working harder (according to WinISD) - for a 0.9cuft enclosure tuned to 35Hz, the system is actually less efficient (amp wise) between 25Hz and 55Hz

Kelvin


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## eviling (Apr 14, 2010)

this is good stuff  really learning a bunch  i could handle that box build.

i never knew it gave it an out of phase response? can i sightly rotate the phase with a higher end procssor to loose that? like say a ps8 i believe is now the top dog.


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## subwoofery (Nov 9, 2008)

eviling said:


> this is good stuff  really learning a bunch  i could handle that box build.
> 
> i never knew it gave it an out of phase response? can i sightly rotate the phase with a higher end procssor to loose that? like say a ps8 i believe is now the top dog.


Not really... I believe the port gives an out-of-phase sound (180° from the driver) from the port - so you'll need to have the enclosure in the trunk while having the end of the port close to you in order to bring most of the sound from the port back into phase 

Kelvin


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## eviling (Apr 14, 2010)

cajunner said:


> haha........
> 
> 
> the out-of-phase comment, please disregard my observation!
> ...


Well its interesting to me I competed with a jbl gti 12" in a ported box. I accualy used to have it fire out back but once I took my 6x9s out I aimed the port at the whole and noticed a better sounding base more so than just the general impact increasing. So maybe I stumbled onto that on my own ? 

FYI that box was an eBay box. A few yrars back if you recall theri were a few people building em for the gtis before stock got rare

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## subwoofery (Nov 9, 2008)

cajunner said:


> I don't understand this?
> 
> are you going off of the impedance peak at resonance to describe the power the amplifier is putting out?
> 
> ...


Just going with what I learned from WinISD, see below: 









Input is 360 watts for both enclosures

SPL graph for reference: 









Kelvin


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## eviling (Apr 14, 2010)

that helix B won't touch 360 into those i dont think...its a nice amp but its nothing beastly by any means, its pure SQ.

the max these will reach is 110? thats pretty low. i suppose they are only 8's on 300 watts though


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## subwoofery (Nov 9, 2008)

eviling said:


> that helix B won't touch 360 into those i dont think...its a nice amp but its nothing beastly by any means, its pure SQ.
> 
> the max these will reach is 110? thats pretty low. i suppose they are only 8's on 300 watts though


If you're talking about this amp, it says 360 rms @ 4 ohm mono 
German mag tested these to put out 440 rms 

Kelvin


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## eviling (Apr 14, 2010)

..im running 2 subs each on their own channel is D4. 2 ohm load on each channel.

you ran your test with 360 total for both? why would i bridge it when i could get 600 watts total rather than 360? the specs are 150-300 , the amp does exactly that at 14.4 with 2 ohm load. these were my intentions anyhow.

I COULD get it to a 4 ohm load wired together yes and i could bridge it and run like that if it is preferable but i thought the 2 ohm 2 channel load would work better and i could put a sub on each side..although direction isnt importent. id like to try it my self. I've heard cars with right left subs...i liked em, granted you cant tell the direction of a sound below these frequencies, the cars noises resonate at frequencys i can pick up and your brain auto tunes to this as an adjustment i believe? maybe im mistaken, it was just how i was thinking., i only came up with the dual box last night though. i mean if ima run em on their own channels might as well well split em, or bad idea? i could run them each behind the rear tire fender in a half box glassed into the corners, or a full box glassed in and finished in trunk liner.


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## Oliver (Jun 25, 2007)

subwoofery said:


> If you're talking about this amp, it says 360 rms @ 4 ohm mono
> German mag tested these to put out 440 rms
> 
> Kelvin





> The B2 has an integrated temperature controlled cooling fan that can be switched off if desired. The turn-on temperature as well as the maximum power of the cooling fan can be adjusted by two separate controls. The connection of an external fan is possible.
> 
> Cont. power rating RMS / Musik an 2 x 4Ohm at 12 Volt: 2 x 80 Watt
> Cont. power rating RMS / Musik at 2 x 4Ohm an 13,8 Volt: 2 x 100/165 Watt
> ...





> *Kelvin*
> After modelling, I like 1.3cuft tuned to 27Hz - a 4" round port makes the vent 33" long.
> Transfer function -3dB is around 40Hz which should mate well with the cabin gain of your sedan


The ratings appear to be conservative, I'd put both subwoofers in 1 box and run a port as described by Kelvin, for what it is worth.


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## eviling (Apr 14, 2010)

Oliver said:


> The ratings appear to be conservative, I'd put both subwoofers in 1 box and run a port as described by Kelvin, for what it is worth.


So I should run it bridged into the pair at 4 ohms

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