weird question about airspace and subs, help me out

[mr_tinkertrain]

i have a box loaded with 3mtx 6000 series subs which i bought as a package from the manufacturer. The box really doesnt have enough air space for the 3 subs. If i were to just unwire one sub but leave it in the box, would the subs hit better?

 

[grodgers]

Doesn't have enough airspace?

i have a box loaded with 3mtx 6000 series subs which i bought as a package from the manufacturer. The box really doesnt have enough air space for the 3 subs. If i were to just unwire one sub but leave it in the box, would the subs hit better?

Please explain why you think this is so? If it's an MTX pre-loaded enclosure, it seems to me that MTX would have optimized it for performance.

The short answer to your question is no - don't just unplug one sub. The right answer is make sure you're throwing the right amount of power at it (it'll take 750 watts RMS at 4ohms if it's the sub box I'm thinking of).

 

[Cobra01Vert]

don't unplug the 3rd sub, it will then act like a damped passive radiator and mess with the sound. MTX box should have been made for the subs, don't worry about a high tuning point as a car's inherent small airspace makes a big boost in lower freq. unlike a normal room.

Same Q as above, why do you think that it is too small?

 

[mr_tinkertrain]

normally you see a 10" sub in boxes much bigger than this, and with 3 all together it really just doesnt seem like enough.

 

[mr_tinkertrain]

i really didnt have the funds for 750 watts rms at the time, so i've gotten an mtx 801d amp rated at 400 rms @4 ohms, BUT i've heard from several people that its actually underrated and puts out about 500 watts rms.

 

[mr_tinkertrain]

p.s. it is the box your thinking of grodgers.

 

[grodgers]

Remember....

normally you see a 10" sub in boxes much bigger than this, and with 3 all together it really just doesnt seem like enough.

regardless of what spouses/GF's tell you....

Bigger isn't always better....

 

[mr_tinkertrain]

lol well put but i'm a newb so i really didnt know that. thanks for the info though

 

[Cobra01Vert]

A smaller box (sealed) usually is just tuned to a higher frequency, it also depends on the parameters of the subs. A ported box is also tuned by its box size and the port dimensions.

Don't worry about it.

 

[KWIK9550]

A smaller box (sealed) usually is just tuned to a higher frequency, it also depends on the parameters of the subs. A ported box is also tuned by its box size and the port dimensions.

Don't worry about it.

Sealed boxes cannot be "tuned" in the common sense of the word, only vented. Yes, sealed enclosure generally have a higher F3(3 dB down point), but as mentioned, the low end extension with cabin gain will generally take care of this. AS for the 6000s, they work very well in about .75 cubes each so you should be good, especially being it is an MTX specific enclosure.

 

[Cobra01Vert]

If you change the size of a sealed box, then you change the rolloff point, with a smaller box equalling a higher rolloff, this is what I meant by tune. You can effectively make a box larger by putting polyfill or wool inside it, giving it a larger effective size, with some doing this in ported boxes to effectively change the boxes tuning freq.

 

[KWIK9550]

If you change the size of a sealed box, then you change the rolloff point, with a smaller box equalling a higher rolloff, this is what I meant by tune. You can effectively make a box larger by putting polyfill or wool inside it, giving it a larger effective size, with some doing this in ported boxes to effectively change the boxes tuning freq.

I knew what you were getting at, I just didn't want anyone to get confused if they went to a shop or something and people started talking about tuning vented enclosures. Not trying to be an ass. Most people don't understand tuning on a sealed enclosure and would not even think of one being able to be tuned.

Here are some graphs of the frequency response of your driver. The first one is in a .75 cubic foot enclosure basically in a free field, or just sitting in a large room. Notice the F3 or 3dB downpoint is 43.81 Hz.

Now look at the next graph with cabin gain added. This is response with the enclosure loaded in the vehicle. With the cabin gain your F3 shot to 5Hz. Now you can get an idea of exactly how well your enclosure actually is.

 

[Cobra01Vert]

Didn't take offense, just didn't want anyone misunderstanding me so I clarified. Great graph showing the cabin gain. One of the reasons why car systems hit so hard.
Even going down to 40hz or so isnt bad for a car as a lot of info is in this range and you don't see alot of info below this in most modern music.

 

[KWIK9550]

Didn't take offense, just didn't want anyone misunderstanding me so I clarified. Great graph showing the cabin gain. One of the reasons why car systems hit so hard.
Even going down to 40hz or so isnt bad for a car as a lot of info is in this range and you don't see alot of info below this in most modern music.

Agreed, but a nice 20Hz note is just heaven!

 

[Phoenix00GT]

The box size is right...you just need to make sure that your amp is right...you could safely run an amp that pushes 1000w RMS and that may work better with those subs in that box