Best position for 12 inch sub?

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Best position for 12 inch sub?

Post by aceracer24 » Mon Jun 12, 2006 12:07 am

Currently I am running 2 1o inch Memphis with 500 RMS. Sounds great but not low enough. They are however in a sealed box. Anyway, I have tried them pointing to the back, pointing forward and pointing up. Pointing up I seem to loose some bass forward is pretty good and back seems to be the best for bass. I can't fire them down because of how the box is designed so I was looking for opinions on what seemed to give the best sound quality and bass response as far as positioning goes and how well firing them down might sound.

My reasoning is simple, I want to make a custom fiberglass box but, if I fire the soon to be 12 in any other direction then up, fiberglassing will be a waste of time. I might as well make an all MDF box. As much as I want to make a cool looking glass box, I want the sound to be good. I'm thinking of going with a single MTX 9512-44 or 8512-44. Not fully decided yet if i will go sealed or ported though and since this would probably make a difference with positioning as well I am looking for opinions on that also.

Oh and this will be going into the package area in the back regardless of what box, direction and speaker I choose to go with.

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Post by 73VWBUG » Tue Jun 13, 2006 9:41 pm

Ok first off, the lowness of the bass is all determinent on the sub that you choose. Check the specs, and see if your amp will produce that low before you start.

Second, you'll always get a better response from a box pointed to the rear of the vehicle that "bounces" off the rear and goes forward. Understand though that it also depends on the box type. If your sticking with sealred, this is the way to go.

Third, two memphis tens should get you low enough for where you want to be. From my knowledge, the highest a memphis sub will go is 25 hrtz, which is plenty low for anyone. Check your setting on your amp and deck to make sure that your subs are getting all the wattage and frequencies they are supposed to.

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Re: Best position for 12 inch sub?

Post by 67 Type-1 » Wed May 05, 2010 1:19 pm

How Low a sub plays is determined by the crossover point,not the speaker.The sub will be designed to play in a specific frequency range,but you need some type of crossover to send these frequencies to the drivers.Most amplifiers have some type of crossover on them,if yours doesn't you will have to get an either electronic or passive crossover.Make sure you get one that has a sub sonic filter too.It will stop your speaker from trying to play frequencies that just rob power from your amp because #1 you can't hear them,and#2 they could possibly damage your drivers.There are a lot of crossovers on the market but the best I have found are made by a company called AudioControl.Check them out at

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Re: Best position for 12 inch sub?

Post by GonzoTx » Mon Apr 25, 2011 10:59 am

'73 and '67 are both right TO A POINT. The low notes you are looking for are really dependant on the size and type of enclosure you use.A properly designed ported (2nd or 3rd order band pass) can go lower than a sealed box,but it tends to be "boomier" and looser.I like to listen to metal and classic hard rock and a sealed box gives you the "punch" you need for this type of music. Ported boxes work well for hip-hop and other types of music where you want the boom.
Look for an electronics retailer who has a box building program and will run your drivers (speakers) specs and print out box volume,port size and length etc. to get the best performance for your $$$$.Make sure to tell him you are putting the box in a Bug. The shape of a Beetle acts like a horn and will actually give you up to a 10 db boost in the lower frequencies !

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Re: Best position for 12 inch sub?

Post by Buggin_74 » Mon Apr 25, 2011 7:29 pm

GonzoTx wrote:Make sure to tell him you are putting the box in a Bug. The shape of a Beetle acts like a horn and will actually give you up to a 10 db boost in the lower frequencies !

So many people don't realise this, I wish I had $1 for everytime I've heard beetles are no good for a big ICE setups.

My bug with the same setup from our shop demo Suzuki Swift hatch pulled 5.8dB more.

Also heed the advice of Gonzo, ported enclosures will get alot lower frequency response but box design, capacity and dimensions is far more critical with a ported enclosure than sealed.
1974 Germanlook 1303 Suba-Beetle
Subaru EJ25 Boost R 17", 4 Wheel discs, Topline suspension and A/C

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Re: Best position for 12 inch sub?

Post by volksbugly » Thu May 05, 2011 3:07 am

ok so here is the good stuff...

correct the low sound of bass does depend on its specs. of the subwoofer, and crossover points, but those are only two of the points that can actually be negated by acoustic design of your box. I've competed in car audio for years, sound quality and SPL. I had a 1967 vw bug with 12 12inch subs, we learned alot with that setup.
ok that said to my point...

the lower frequency the sound wave the longer it is. If you want to have that sweet sound you need to tune it so at your head it resonates at about a 20 hz note. That said this is where the science comes in, figure out how long a 20 hz note is, then calculate from your speaker source the distance it will travel to make that note be in tune with reflected notes of the same frequency. You want this frequency to amplify at your head. There is software that is available and also you can take it to a reputable car audio store, one that actually has a audio spectrum analyzer. let them pump pink noise and measure at your head. it will probably peak around 110 hz. (thats what mine was) but each car is different.
To get this lower you can sound deaden the entire car but you still have huge reflective points ie, your windows. after I did all my sound deading the best peak rta I could get was 60hz. I would suggest just making the sound bounce as much as possible. I personally am going to build a down fire box, but down firing into wood (Part of the box) not the cargo area metal. my box is going to be a little shallow ie narrow so the sound will bounce off the back of the back seat, then off the box front face then the sound will come out between the back seat and box, next the sound will bounce of the inside of the roof and back glass, then it will bounce off the front glass and resonate with itself somewhere. Just remember the longest the distance it has to travel the lower frequency resonance will be closer to your seating spot.
now thats just one direction that the sound will take, it is of course infinate, but that is the direction most sound will take,

good luck

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Re: Best position for 12 inch sub?

Post by volksbugly » Thu May 05, 2011 3:16 am

GonzoTx wrote:'The shape of a Beetle acts like a horn and will actually give you up to a 10 db boost in the lower frequencies !

an increase of 10 decibels in sound represents a DOUBLING of
the volume. That means that 70 dB would be TWICE as loud as 60 dB.

The term decibel (dB) is defined as dB = 10*log(P1/P0) where "log" is
base 10 and P1 and P0 are the actual sound excess pressure between two
pressures P1 and P0. ... g99325.htm

Many people misunderstand db ratings, I used to misunderstand it till I was schooled :)

:) cheers

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Re: Best position for 12 inch sub?

Post by Rodek » Mon May 13, 2013 9:33 pm

I applaud your efforts to achieve good sound in your car! First and foremost, ensure you have a good source unit. One that's capable of driving your amplifier with good clean signal. Also ensure you have run the proper sized power cabling for your amplifier's electrical current demand. Good signal wires (RCA cabling for example), speaker wire, the ground wire and the routing of all wiring is important as well. Now, if you've already done this, you're headed in the right direction.

The subwoofer should sound great providing its in the proper enclosure. By proper I mean an enclosure designed with the optimum amount of airspace that your woofer calls for. This is true for sealed and ported designs. A custom fiberglass box can look incredible and still perform with subpar results if it's not providing the correct amount of air space.

Also be sure the woofer's ohm load isn't lower than your amplifier's recommended safe ohm loading. I also agree with the post above about sound deadening. You don't have to go overboard as it does add weight to the car. Just be critical in it's placement and you should achieve satisfactory results. Be careful about bass boost, turning amplifier gains wide open and adequate amplifier cooling.

Finally, do you have a single or dual voice coil subwoofer? How is it wired to your amplifier and are you certain that your amplifier provides 500 watts RMS to your woofer?

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