Sub Positioning

[Chris Mac]

im currently running 2 infinity 12" subs, im getting 141.8 db from the (cruise control) but, as youll see in the photo below, the magnet is sitting up, would it make a difference for sound offs if the cone was facing up??

or is it 6 of one, half a dozen of sed other??

 

[-Pete-]

its a bit of a hit and miss thing at times and it may only be clear with testing it for loudness when used inconjunction with a meter to see what changes are making what results.

by putting the cones up the right way you will effectively reduce the internal volume of the box but this will make little difference to the loudness. if youre looking to get loud then make a dedicated box designed for those subs and for spl. simple as that.

by mounting them properly or not you might gain something or you might lose something, either way the change would be tiny im sure.

are you that keen to go for spl? or do you just want lots of wobble and the subs to go low?

you cant go for balls out spl performance and still have sq and useable subs for everyday driving. there has to be a compromise between design and function.

 

[Nicky]

Would ported boxes not enable him to go a bit louder (if tuned right), or does that only affect the note he can hit?

 

[-Pete-]

yes a ported box will IN THEORY give a 3db rise in output but this isnt always the case. a ported box will usually give a smoother low end roll off and a bit more output but at the loss of tightness and absoloute low end.

if he wants spl then go ported all the way. if he wants a compromise due to wanting to listen to his subs for daily use then he wont be able to get maximum loudness due to the box design needing to be functional for daily use.

 

[Nicky]

Your on TA too much lad lol

 

[-Pete-]

well over 5 years now

 

[Nicky]

I rest my case... lol

So a ported box is for smoother bass at the bottom freq's, but the well designed box would be more appropriate for daily, more conservative use?

Sorry, im still trying to learn about this stuff..

 

[-Pete-]

I rest my case... lol

So a ported box is for smoother bass at the bottom freq's, but the well designed box would be more appropriate for daily, more conservative use?

Sorry, im still trying to learn about this stuff..

well you want a well designed box for whatever application you want, be it sound quality or spl etc. but yes you would have a ported box for a bit more low end wobble and output. a well designed box with the right sub can tick a lot of boxes but for dedicated things only certain boxes will do. for dedicated spl then only ported will give the most output

for dedicated sq, then either IB, Aperodic or sealed are the ways to go.

 

[Nicky]

for dedicated sq, then either IB, Aperodic or sealed are the ways to go.

Like all the other members of RMS, you agreed to English as the only language you use on here, so please do so...?

I know sealed is as it says, a sealed box with no ports, but what the hell are the others? Please elaborate..

Cheers
Nicky

 

[-Pete-]

sorry, i know the others are less well known.

ill keep it brief and simple for now as im heading to bed asap!


an IB set up is short for Infinite Baffle. this is the same way your door speakers are mounted. this means that there is no enclosure as such, just the panel of a door or using the parcel shelf(but only if specifically designed and to do so!!)
Infinite baffle applications for a speaker require the front and rear waves to be seperated from each other in order to create the porper sound and stop the waves interferring with each other.
normally this is ok by the use of mounting your mid to your door or a sub to a large baffle(baffle is just the word for the bit of wood or metal you would mount the speaker to)

Infinite baffle applications are most common in saloon cars where the boot is sealed off from the cabin of the car. people will then mount a sub in the ski hatch firing into the cabin using the boot space as an enclosure or mount it on the parcel shelf as it is usually made of metal and pretty strong to mount mdf or wood too for support.

Infinite baffle has great advantages over other methods, but and this is a big but, a sub HAS to be able to be used in such and application. you cant just whack any sub into this type of situation, the sub has to have certain properties in order to work correctly in an infinite baffle set up.

anyway, thats a very rough explanation of infinite baffle but i cant really cover it all in a few lines as theres loads more to say on it !!!

and aperodic(spelling might be a bit off) is a lot more complicated in terms of how to describe it but it is basically a box or enclosure that can be used for any speaker or sub. it uses a very tightly fitting enclosure that would literally be not much bigger than the rear of the speaker and then at the front or rear, mount a resistive membrane to control the air pressure of the speaker.

its pretty technical when you get into the nitty gritty of it but thats as basic as i could be about it.

its also great where space is at a premium and can have some seriously good results when used correctly in sq stereo applications.

 

[Nicky]

Noted..

Cheers Petey lad.. Proving once more to be a more than adequate Ice advisor

 

[-Pete-]

thanks, if i can offer more info on that stuff then feel free to pm me, im more than happy to help when i can.

 

[daves106]

now u r just showing off pete lol with my ported box i am finding its louder musically but not a lot louder than sealed because sealed boxes peak higher and are using the power better plus if you were to try and fit those 2 subs in a ported box in your boot it would end up looking like mine and take up the whole boot lol

as for back in or back out i dont think it would make a lot of difference only one way to find out give it a go and see

 

[Chris Mac]

so, as far as db, there shouldnt be a great difference?

dave do u think a box like yours would make a big difference? how did you find out the dimenstions for yours? is there a site for different subs and the correct size?? fancy a wee winter project for the long dark nights

 

[-Pete-]

yes a box like daves would make a big difference. a box like daves being a dirty big ported thing!

if youre after more output then yes a ported box is what you will want. to make a correct ported enclosure you will need to get the specific details of your sub and its properties and then give them to someone who can design enclosures properly.

then once you have the design its a simple case of putting the box together and dropping your subs in, but realise that a ported dual sub box will be pretty big and bigger than your current boxes. well thats depending on the current size of them? how big are your current boxes? 1.25 cubic foot or bigger?

 

[daves106]

someone designed my box for me on talk audio if you are serious about spl you will need to do something similar to me and fill your boot completly with a box i would also reccomend a port which you can change so you can listen to it as well because a high tuned port for spl will not sound the best

what subs are they and a ported box will be bigger than a sealed box so to fit 2 12's in it will take up your entire boot

 

[Boydie]

didnt read it all but you will get better SQ if you bin the 6x9s

also the magnets from the subs and 6x9s will interfere being so close

 

[-Pete-]

forget interferring boydie, the 6x9s are getting hammered by the air pressure of the subs. heres a wee test for anyone running a sub or two in the boot and 6x9s on the shelf, disconnect the 6x9s and just play things normally and watch what happens. and for the rest, heres what happens, the cone will still move loads due to the pressure on them from the air moved by the subs. this is why its pointless having 6x9s and a sub/s in your boot, they cant even function properly!!!

 

[Boydie]

know that - thats why i took mine out years ago lol as well as all the other speakers i wasnt using because they vibrated from the force of the sub

 

[Chris Mac]

of first of all, its for SPL - and the 6x9's are out for th sound offs obvioulsy, the rest of the time the music isnt reli turned up that high, and the bass is turned right down, so the 6x9s wont be getting much of a beating from down below.

dave, u think if i posted up on talk audio someone would design the package for me??

 

[-Pete-]

yeh they would but you will need the TS parameters of the sub or at least know the model etc so you can find the parameters for them

 

[Chris Mac]

yea i know the subs, infinity 1240w

should i just post and ask if anyone could do i for me??

 

[andy_gdon]

I dont think you'll see much more from the infinitys' to be honest! what amps are you running? what are the RMS figures for the subs and amps

 

[-Pete-]

you need more than that, you need the parameters for them, the fs,vas, qtc,qms etc, it will be a big list of things. if you dont have these you will need the model number of the sub. you wont be able to make a correct enclosure specifically for the sub without the parameters

is that the model or just the number for the watts (infinity 1240w??)

 

[focus_rs_jonny]

nope thats the model infinityt 1240w - but they are 1200 W subs

theres a 4 channel 1200 watt amp powering them