29 replies to this topic

[shizzle]

Heya,

I am building a ported box for a family member, and have a very simple question.

Does the port have to be on the same side as the woofer?

Logic tells me any face except that directly behind the woofer should be fine. I would like to add aport on the side adjacent to the woofer, because of space constraints. IF this is possible, is there any preference to where on that side it goes, ie, farther from the woofer as possible etc.

Also, any opinions on the best orientation of a port in a hatchback? For example facing up into the car, back towrads the tailgate etc? I know the best way to test is by putting it in the car and moving the box around, but this is not possible unfortunately.

Thanks in advance for any help.

Cheers,

[D34M0N.inc]

Have it load of the hatch but either way it's fine to not have it on the same side the subs on

[shizzle]

Thanks, by load on the hatch you mean face backwards towards the tailgate?

[Lunchbox.inc]

perfectly fine to have the port on another side to the woofer...

generally in a hatch, subs up port back (towards the tailgate) works well... but it really comes down to the car, i found in my civic port facing the passenger side rear 1/4 sounds great to my ear,

generally there isn't much you can do "wrong"

[D34M0N.inc]

Yeh pretty much, sub up and port facing the tailgate

[Damon]

Best arrangement is both sub and port on same face, both facing backwards towards the tailgate.

[shizzle]

Thanks guys, appreciate the replies.
I wiill face thew port backwards as per Damons description. All it means is that I will have to put an elbow on the port and turn it inside the box to get the legth required.

Cheers,

[Lunchbox.inc]

Best arrangement is both sub and port on same face, both facing backwards towards the tailgate.

and why do you say this...?

i'm really interested to know the facts behind why this is the "best arrangement"

[D34M0N.inc]

I found numbers to be better with sub up port against tailgate and sounded good to.

[Damon]

and why do you say this...?

i'm really interested to know the facts behind why this is the "best arrangement"

I conducted numerous comparison test back in the '90 that I published back then that compared all manner of loading positions in sedans and hatchbacks - essentially covering 'one box' and 'two box' vehicles. I conducted these tests with sine wave measurements at individual frequencies from 30 - 100Hz with the microphone placed at the driver's head position.

Since then I have continually experimented with loading and every single time it has arrived at the same result. I think you'll find a great number of people will agree that this technique has provided the most reliable high output for bass loading in virtually any car.

From I scientific perspective I think you'll find that this arrangement simply yields the longest pathlength within any type of vehicle.

[Lunchbox.inc]

i can accept that you may have done some tests and whatnot over 10 years ago, but to say without ANY regard as to what vehicle or what gear, that subs back port back will be the best configuration is just simply stupid

for a start, i can honestly say i have not seen a truly successful build with subs and port firing back, and those cars that have had some success, have usually been wagons, not hatches...

Edited by cni.xobhcnuL, 19 February 2012 - 07:11 PM.

[Lunchbox.inc]

hmmmm... haven't found any subs back port back setups yet...

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seems to be everything EXCEPT subs back port back... and there is alot of different boxes, in alot of different cars, with alot of different gear...

Edited by cni.xobhcnuL, 19 February 2012 - 06:53 PM.

[SHANE G !!]

i'll be running subs up and ports back in my wagon,,hopefully successfully ,will be interesting to see how it works with my vehicle /gear/power.

[Lunchbox.inc]

i'll be running subs up and ports back in my wagon,,hopefully successfully ,will be interesting to see how it works with my vehicle /gear/power.

i would think you should have some success man, subs up port back is a great way to get loud... not always the "best" orientation, but usually makes for a damn good starting point!

[Damon]

With extreme SPL applications as you have shown it is obviously impractical to have massive ports and subwoofers all firing rearward as there simply isn't the sufficient space on the wall of the enclosure in these instances. But this is not such an installation. This is a regular subwoofer in a regular car.

[D34M0N.inc]

My EF gained 1.2db going from sub and port back to sub up port back seemed to get allot better airflow and flex the car allot more.

[paulxr6]

I loved all those articles in Car Stereo Australia. So much info!

[shizzle]

If it makes a difference the woofer is a OZ Audio 300L (12" rated at around 250W) running off around 250w of power. Car is a Toyota Yaris, and install is just a small one, not SPL based (although beigng 16, you can bet it will get a hammering )

Due to box dimensions, I will probably go sub and port back, only because the sub will not fit on the top of the box as it is only a 200mm face.

Thanks again, and lets not get too heated here.

[Lunchbox.inc]

With extreme SPL applications as you have shown it is obviously impractical to have massive ports and subwoofers all firing rearward as there simply isn't the sufficient space on the wall of the enclosure in these instances. But this is not such an installation. This is a regular subwoofer in a regular car.

i won't get too into it, but i will put it simply...

it has NOTHING to do with practicalities... SPL cars are clearly not about being practical, they are built a certain way, because they are loudest that way, not because it is impractical to have all the woofers on the same face as the port and firing backwards...

just because it is a regular car, with a regular install, doesn't means anything, if it's louder in an SPL install, it will be louder in a daily install, it goes without saying that Shizzle isn't going for an SPL setup, and with only 200mm depth, a woofer isn't going to fit firing up... thats fine, in this situation, (as you said it's a regular install) there won't be a huge difference in port orientation, design it as it will fit best, if the port comes out the side, so be it, the audible difference would barely be noticable...

but my point is that you are giving false information, and stating it as fact... if any n00b were to come on MEA and start stating false information, as tho it were fact, without any leeway, just blanket information, they would be shot down pretty quickly, but because you come on here and say just as false information, we should take it as truth...? the sad thing is that due to your many jobs in the industry, alot of people actually look up to you, i know i myself used to look up to you, i used to read everything you'd print in hot fours as if it were the god honest truth, my 1st car was filled with Jaycar gear, solely because YOU said it was so great... of course i later found out that EDITED: your unbiased opinion was not quite as "unbiased" as it should have been having infact worked alongside Jaycar to produce alot of those products, but alot of people still look up to you, you have a responsibility to provide the general public with an unbiased opinion, in this case of which port orientation will work best for the OP, instead you make a blanket comment, with wrong information, and then when i pick you up on this fact, you have the gall to tell me to mind my tone, as if your some kind of Audio Elder that should be spoken to in in a "nicer than most" manner...?

i will happily speak to you with the same respect that you give me, or anyone else...


EDIT: i went back and edited a little, just to make it a little "nicer sounding"



sorry about this Shizzle, as i've kind of answered above, in this situation, the port orientation isn't going to make a huge audible difference, as long as it's not firing forward, or completely blocked, you should be fine... just make sure you allow enough room around the port for it to breathe, and you should be fine!

Edited by cni.xobhcnuL, 19 February 2012 - 11:44 PM.

[D34M0N.inc]

^ Well said

[ubernoob]

From what I understood(before I read this thread) is that the wave coming off the front of the cone is reinforced by the backwave which is delayed by 180deg by sneaky port tuning. If that is true it would make sense to have the port on the same face as the woofer to get both pressure waves loading off the tailgate at the same time.

Apologies for the terminology I still struggle with this sort of stuff.

[Lunchbox.inc]

From what I understood(before I read this thread) is that the wave coming off the front of the cone is reinforced by the backwave which is delayed by 180deg by sneaky port tuning. If that is true it would make sense to have the port on the same face as the woofer to get both pressure waves loading off the tailgate at the same time.

Apologies for the terminology I still struggle with this sort of stuff.

yes and no, you are correct in wanting the backwave delayed (in a sense) 180deg but the practical side of that is alot harder...

to delay the rear wave 180deg, at 40hz the port would need to be over 4 meters long for a full wave, but at the point your rear wave is 3db down... and for the 1/4 wave, it's still over 1 meter, to turn the 1/4wave 180deg... so even in this situation, it becomes VERY hard to make use of this on the same baffle in a hatch back, in a wagon it's a little easier because of the added length in the car, if you can do so, it can work in your favor, BUT there's other losses that come into account too, such as the distance from the baffle to the tailgate, and back to the windshield, as such this style of common baffle is often best left to walled cars, where you can play with the distance from the windshield to the baffle and from there to the rear wall......

BUT when running subs up/forward, port back, the distance between the port to tailgate and back to the woofer, then gives you the room for the rear wave to turn 180deg... so.. the rear wave may leave the box somewhat out of phase, but as it passes the woofer on it's way forward it ends up back in phase... or at least thats what we try for...


thats definitely over simplifying it all, but you get the gist...

[Damon]

When anyone comes onto a public forum and makes any statement it is a universal understanding that it is simply their opinion - that is all. It is also understood that others may have an alternate opinion that they are free to share and discuss this. Normally, forum etiquette says that this is done in a civil and respectful manner. Something you may need to consider.

Getting upset by comments made by me or anyone else simply because you disagree, then making personal attacks is not the answer. Nor should it be tolerated here at MEA.

At no point did I ever state that my opinion is irrefutable fact so do not place such words in my mouth. This is something you have arrived at, not me.

Nor do I have the time/inclination to write a white paper evey time someone asks the same old question about bass loading that has been discussed in these forums for over a decade.

[ubernoob]

Cheers Lunchbox, that makes sense, makes me want a badpass box so I don't have to think about any of this.

[Lunchbox.inc]

Best arrangement is both sub and port on same face, both facing backwards towards the tailgate.

all i'm saying, is that this above, which i have quoted, does not anywhere state, that this is only your opinion which may not be correct, it is stated that it is the "best arrangement" as if it is a blanket statement, and there is no other possible outcome...

if you do not have the time, nor inclination to "write a paper" for these such questions, then why bother posting at all...? considering that Shizzle's question had already been answered by 2 members, i can't see any valid reason behind why you would reply with a contradicting answer, and have no time nor inclination to go into any depth about why you've recommended what you have...? other than saying you've done some tests 10+ years ago showed it to be best...

people take your word as truth, just try and remember that, if you don't have the time nor inclination to reply properly, then maybe think twice before hitting reply? the people who you or i are replying to deserve our respect, and if we're going to make a blanket statement one way or another, we need to be willing to provide 100% evidence that that is the case...

Edited by cni.xobhcnuL, 20 February 2012 - 01:31 PM.

[DrBoom]

"People taking your word as truth" , No, this is an opinion expressed by Damon, but he is also backing his theory up with practical tests he has carried out and I second his opinion having tried and constructed many subwoofer boxes. Those pictures posted her only apply to "spl" vehicles as those massive ports will be an hinderance to everyday boot use.

As stated, the best result in an automotive environment is achieved by having both driver and port on the same baffle and facing towards the taillights will achieve the best "bass" in the car. however, in most cases, and the car owners choice may not depict this theory but the end result is, that the person driving the car is happy. BTW, my subwoofer is placed facing the right hand corner and I am happy with the result as it provides "corner loading" in my car.

Thank you for your professional input Damon!

[~Samuel~]

Great thread.

[SHANE G !!]

lets all agree to agree that the try it and see method, or if you want a challenge go with what "you" like ....life's too short for d@#k measuring comps lol

Edited by sostok, 27 February 2012 - 06:20 PM.

[Equilibrium1990]

I have two Alpine SWR-1043D's going into a ported box next week and the port and sub will be firing at the tailgate, Will post result if anyone is interested :-)

[shizzle]

Just an update for this thread.
Ended up putting the speaker and port on the same side, and facing them backwards.

This was done due to convinience. I did end up facing the port and woofer forward once the box was made, but found the rear facing to be better (did not try it facing straight up).

As a side note, I am amazed at the output the the single 12" Oz. It is not a hugely powerful woofer, and only running off around 280w (although it is nice clean power from a DLS amp). The bass it produces rattles not only the car, but some of the windows in my house. REALLY amazed, and it reminded me just how much I miss hatchbacks