sub enclosure advice from audio gurus

[clipto333]

hi,

im planning to build a sub enclosure for my pio subs.
i have 2 304c 12" and im planning to use 2 seperate enclosures for it.
plese advice on the specs of the enclosure(box volume, vent dia, vent length and dimensions if you can).or should i use a sealed enclosure? i have a hyundai accent crdi and i dont care much about the boot space. i like low freq bass. please reply as soon as possible.

in future i might buy 2 pio 306dvc. can both the subs use the same enclosure.
never mind if it cant. ill build a new one then.

currently my subs work best on 50 hz and above. i used my laptop with winisd sgnal generator.connected it to my amp. i have a x944 pio. i wanna go lower much lower if possible

[Sam Kapasi]

Clipto, to determine any subwoofer enclosure, you need a set of data about the woofer, called the T-S parameters (Stands for theile-small)

Once you have these parameters, there are a host of box calculating software (mostly free) that will give you exactly what you want.

I say, go online, find these parameters, get a box calculating software and do it yourself!!

Forget these silly gurus, it will be most fun to do it that way

[low_bass_makker]

Here you go for the t-s parameters...




I would say go for a bit large enclousre like 1.5 - 1.6 cu ft and it will decrease the qtc and the low freq which you require will increase....

dont go for ported as the sealed enclosre can reporduce the low end efficently than the ported ones....

here is a link for calculating the internal volume of the box...

Woofer Enclosures - Fraction to Decimal - Parallel - Series - Port Length and Volume Calculators

[navin]

Yes 1.5 cu. ft. selaed seems about the minimum. However if you need a smaller box you can always use an aperidic vent to reduce the Qtc (Q of woofer in box).

[Sam Kapasi]

NAVIN! He's a newbie, old man, don't make someone faint just by reading your sentence.

Clipto we are here, if you decide to do it yourself, we will help you online.

[Vivekphadnis]

I know Navin to be a big fan of the aperiodic vent.

[Bass&Trouble]

Originally Posted by Vivekphadnis

I know Navin to be a big fan of the aperiodic vent.

ha ha ha ha haaaaaa

Good one. Heavens, some of you have an insane sense of humor and pun-dropping timing.

[Sam Kapasi]

b&T, i don't think Vivek meant it that way, as a pun, but now I realise, that is pretty funny.

[navin]

I am solely becuase almost all of us want to stuff big subs in small boxes. I find in many cases the AP vent is nicer on the ear than electronic Q control. Then again you can AP vent everything (you might as well go for Open Baffle if you do). An AP vent can help if the Qtc is between 0.7 and 1.0 and can drop that to a less boomy level.

Sam you are right, I should explain Qtc.

Clipto.

a) if you have 2 subs you need twice the volume. What you can do though is build a 2.5-3 cu. ft. box if that will fit and then you can put one sub in and add a second later (with the AP vent mentioned above).

b) A speaker has electrical (primarily related to the voice coil) and mechanical (primarily related to the suspension and cone mass) characteristics. These are known as Qms and Qes (m for mechanical). Since the woofer is not in a box these numbers are taken in "free-air" or without a box. see pic below. Qes and Qms are often combined to give Qts (t for total).



Once the speaker is in a box the mass behind the speaker changes and hence the Qts changes and this is known as Qtc.

Hope this helps.

[navin]

The pic above is not how we meausre Qts (these drives are being "run in") it was just to show drivers in "free-air". And if anyone recognises the make/model of these drivers I'll send them a cigar!

[gunbir]

Originally Posted by navin

And if anyone recognises the make/model of these drivers I'll send them a cigar!

I see some Scanspeak in there... and possibly some Aurasound... not sure though... I could be totally off... cant see much

[panky12345]

Originally Posted by gunbir

I see some Scanspeak in there... and possibly some Aurasound... not sure though... I could be totally off... cant see much

but gunnu doesnt smoke....

[clipto333]

Originally Posted by navin

I am solely becuase almost all of us want to stuff big subs in small boxes. I find in many cases the AP vent is nicer on the ear than electronic Q control. Then again you can AP vent everything (you might as well go for Open Baffle if you do). An AP vent can help if the Qtc is between 0.7 and 1.0 and can drop that to a less boomy level.

Sam you are right, I should explain Qtc.

Clipto.

a) if you have 2 subs you need twice the volume. What you can do though is build a 2.5-3 cu. ft. box if that will fit and then you can put one sub in and add a second later (with the AP vent mentioned above).

b) A speaker has electrical (primarily related to the voice coil) and mechanical (primarily related to the suspension and cone mass) characteristics. These are known as Qms and Qes (m for mechanical). Since the woofer is not in a box these numbers are taken in "free-air" or without a box. see pic below. Qes and Qms are often combined to give Qts (t for total).



Once the speaker is in a box the mass behind the speaker changes and hence the Qts changes and this is known as Qtc.

Hope this helps.

hi guys,
i just installed my new enclosures in my car. each one is a 56 litre box with 3.75 dia vent about 8-9 inches long. its not finished yet but they have come out to be huge. and thank god they are cause i mistook my subs model no. its 304f not c its the free air one. i connected the to myy 944 bridged. man they are rocking like hell. i knew there was some problem with my earlier enclosure. the installation guys here take you for a ride man. they make the box accordin to your car and not the sub. was really pi$$** with it. i tried three different cars as i thought there was something to do with car acoustis. i tried it in my octy(my car got stolen thank god i removed my system). then in my palio(it got totalled hehe) then fiesta and now accent. its like improvement of around 200% and im not kidding really. il post pictures when i get time. Happy New Year to All you BHPians and The Audio Gurus. i Have a suggestion which ill post a little later got to go now.

Thanks

[Vivekphadnis]

Originally Posted by Sam Kapasi

b&T, i don't think Vivek meant it that way, as a pun, but now I realise, that is pretty funny.

There was no pun there. But now I realise what it could also mean. Sorry Navin.

[navin]

Originally Posted by clipto333

hi guys,
i just installed my new enclosures in my car. each one is a 56 litre box with 3.75 dia vent about 8-9 inches long.....its 304f not c its the free air one. i connected the to myy 944 bridged. ... i tried it in my octy(my car got stolen thank god i removed my system). then in my palio(it got totalled hehe) then fiesta and now accent. ...Happy New Year to All you BHPians ....

You got the 306F in a bass reflex box. From the looks of the box it might be some sort of an EBS alignment (extended bass shelf). Never mind you are happy and that is what matters. For academic purposes I would love to hear your views with the port plugged.

BTW, You seem to have awful luck (one car stolen, another totalled) and great sprit to still be wishing us a Happy New Year. Hope 2007 is not as "exciting".