Reflection Of Soundwaves Of Box Design

[PaulO2288]

Ive always been wondering how a certain box design can get loud. For example when you do subs back (sealed) and or subs back port back you are reflecting the soundwaves to the front of the vehicle and concentrateing the soundwaves to the front where the meter and listener are. Walls are self explainitory, they concentrate the soundwaves right up front to the meter and listener and keeping in enclosed in that area and also making it less area to pressureize and compress. Now subs up port back seems to baffle me on how its louder in suv's and etc. Subs concentrate the soundwaves up towards the roof and port back. Soundwaves are boucing around up and down in the car from roof to floor and ports faceing back. I understand how the port would concentrate the sound to the front and throughout the car but I dont understand how faceing it up would concentrate it through out the car.

[Ray]

depends on weather you have enough pressure to compress the cab or if you need the face them back.

for instance i only do subs up if i have enough woofer... to get pressure.

Like 2 15's in a small suv, or 2 18's in a large suv..

[PaulO2288]

depends on weather you have enough pressure to compress the cab or if you need the face them back.

for instance i only do subs up if i have enough woofer... to get pressure.

Like 2 15's in a small suv, or 2 18's in a large suv..

Yeah because when I was messing around with my box I had tried it with subs up port up because im normally subs back and port back and it wasent nearly as loud. You could barely even hear anybass. But then I went and moved it back to subs back port back and it was a completely different game.

[PaulO2288]

Anyone else have any opinions? Thinking about doing 4 12" CVR's subs up port back but cant decide if 2 12"s subs back port back will louder.

[mtxcivic07]

Anyone else have any opinions? Thinking about doing 4 12" CVR's subs up port back but cant decide if 2 12"s subs back port back will louder.

4 12" subs up port back will wang way harder than just 2 12's facing back... it's plenty of pressure to make the soundwaves hit the front of the car.. DO IT!

[BigPimpin91]

Not commenting on what you should do with your system, but here is my theory why subs up port back is best.

When the woofers start moving there is an immediate pressure difference above the box.

The back wave has to travel through the box and out the port before it can makes it way to the front to cancel out the subs movement.

It's this few milliseconds of time that causes a pressure difference and db.

[PaulO2288]

Not commenting on what you should do with your system, but here is my theory why subs up port back is best.

When the woofers start moving there is an immediate pressure difference above the box.

The back wave has to travel through the box and out the port before it can makes it way to the front to cancel out the subs movement.

It's this few milliseconds of time that causes a pressure difference and db.

Now why exactally is subs up port back louder than subs up port up? The port boucing off the back of the trunk lid or hatch. etc makes it that much louder along with the subs fireing up together?

[Noobtastic14]

how is the transfer function changed with placement of woofers/port?

by bouncing the port wave off the rear hatch/rear door increases the length between the cone and your ear thus lowering the transfer function? also- would adding that distance between the front and back wave decrease cancellation?

-Drew

[PaulO2288]

See ive found a wall is concentrateing the soundwaves and air pressure in the front of the cab by the meter and listener along with shorteing the cabin space so easier to pressureize. Then with a box if you face it back the waves and pressure just have to bounce off the back of the hatch and they are concentrated straight to the front of the cabin, subs up port back the subs are boucing between the roof and floor, dont understand how it would become loud in anyway you know?

[mtxcivic07]

See ive found a wall is concentrateing the soundwaves and air pressure in the front of the cab by the meter and listener along with shorteing the cabin space so easier to pressureize. Then with a box if you face it back the waves and pressure just have to bounce off the back of the hatch and they are concentrated straight to the front of the cabin, subs up port back the subs are boucing between the roof and floor, dont understand how it would become loud in anyway you know?

dude, you probably shouldn't think about this anymore... just think... steve has his subs facing up and port back and what does he hit on the meter???