IceNine

The boys at SR Audio strike again!

After hearing a car that had a Memphis Audio system installed, I just HAD to have the same system put in my car. So Shaun@SR Audio did some magic. He put a 5 channel amp (it actually fit in one of the cubbies that sits on top of the spare), M-class components front and rear, and........

Their M-class 10" DVC sub in the OEM bazooka box. Box was gutted, filled with some tiger hair to fill up some of the inside airspace, and the face was leveled by removing the gain **** and filling the hole with MDF and some glue.

We also added some additional sound deadening material to the mounting holes to make sure there would be a seal once the box was remounted.

The sub sounds amazing in this enclosure.

watcher1307

Am I to understand that you added material inside the box for the pourpose of making the internal volume of the box LESS?????????

IceNine

That is correct, sir. The box itself is quite large and ported to make the cruddy sub that Bazooka includes sound "ok".

If you are going to SEAL the box as Shaun did, you want to reduce the internal air volume to what the sub would consider optimal. In this case, I think Shaun read that it was around 0.75 cubic feet.

watcher1307

Typically, the bigger a sealed box is.......the better. That's why they make polyfil and such products. Tod determine if a box shoule be ported or not....I beleive the equasion is.......2Vsubof-. Had to look that one up! Forgot it for a minute.

IceNine

Well, I let shaun work his magic, and it sounds absolutely amazing. I won't claim to be the supreme master of car audio - but I can say whatever it is he did, it works quite well.

watcher1307

I'm not trying to down you or his work. I was just curious as to why he would do it. I suppose it doesn't matter though. As long as it sounds good, and you like it. Good job!

Shogun

That is actually not true. There are optimum volume for boxes relative to the driver used. There typically will be a range of usable volumes with one optimal size right in the middle. Bandpass boxes need more room and will be more forgiving with box volume. There is no formula for determining if a sub should be in a ported box, they can go in either and is up to the user. Ported vs. sealed have different characteristics that make them good at different things.

That is a good idea! I have been looking into getting the similiar box in the corner. It takes up little room and is not visible when the hatch is closed.

watcher1307

Actually, there is a formula for determining weather a box should be ported or not. The formula is 2Vsubof-. It uses the sub's specs and the box's specs in the calculation.
A bigger box will always provide deeper bass. Weather the box is sealed or ported. Provided, of course, that the proper port tuning frequency is utilized.

sraudio

The reason we added material and sealerd the enclosure is because that is What a Memphis M3 calls for a small sealed enclosure. Box speca out to like 1.7ish and it needs to be about 1 cubic ft

Shogun

After some searching, I saw that there is a formula, though, it will not mean only one type of box can be used. Most manufacturers offer a range of volumes for sealed and ported boxes. The "BEST" volume is right in the middle of the range. There is a reason why you do not want to just go big.

Taken from www.the12volt.com:
Just like life, there has to be balance between all things.

watcher1307

That rule makes sense. However there are times when it doesn't make sense. If you were to take a sub, and put it into a tiny box, it wouldn't be able to take unlimited power. This is not because the cone won't be restrained from vibration, wich is why using a small box is benneficial. It's because of the thermal power handling capabilities of the voice coil.
When using a very large box, even at worst, the sub would use it's "air free" charestics. I would say that it would have to be a very large box for this to be the case. So large in fact that the volume of air outside the box would be equil to the volume of air inside of the box. This is of course presuming that the windows are up, and the doors are closed.
These, being the extremes of box size, are possible, but give us a useable guideline for determining optimum box size. Granted, a larger box will allow the cone more "travel" distance, and a smaller box will allow slightly higher power handling charestics, at the cost of "travel" distance.
These things however, aren't the only guidelines in determining optimum box size. For example, the ability of a subwoofer to change frequencies is determined by box size. Ok, if you've got a small box, and are trying to change the rate at wich the cone travels(frequency), it will take less time. This is because the small box controls the excursion of the cone.
Another factor for determining optimum box size is that a larger box will allow the sub to move more air. This is because a larger box, will allow increased cone excursion at the same power levels.
That's what the whole game is about. Moving air.

iScion

What model of the amp did you use ?