My Car Audio VS My Home Audio

Actually your vehicle will have a lot more room gain than your home.  There are several possibilities why.  My guess would have to do with lower tuning, quite a bit of EQ on the HT subwoofer, and probably some peaking in the response at say 35 Hz or so to give the impression of more low bass than there really is. 

I did notice that the resonant frequency on that Momo sub is somewhat high.  Add to it that you might be using an enclosure on the small size for the sub (only a guess) and you will run into a peakier response with less low end.  The solution is to increase the size of your enclosure.  That will give you the low end you desire.

Steven Kephart

Adire Audio

I agree with Stephen, your enclosure sounds to be your limiting factor.

Your enclosure in your truck is on the small side, which will limit your low end. I know, through reading your past threads, it was designed/built with space restrictions. As opposed to your HT enclosure, which are designed for optimal performance, not the space it takes up.

1.  No, you can normally go very large with either type of enclosure.  For vented, the port volume has to be correct according to the enclosure volume.  Given that necessity for a vented box, for either type it is overpowering that causes overexcursion.

2. First, refer to #1.  Then, for one, one would choose whatever sub is in it's ideal enclosure for the parameters that the sub has.  And as long as the two subs are equal in quality.  A 12" sub will not perform better than an 8" sub if the former is confined to too small, or the wrong type, of an enclosure and the latter has the Taj Mahal.

Use your WinISD program for clues to this.  If you'll put various subwoofers into the database and bring them up, just clicking thru the boxes for automatic suggestions, the program will come up with the best size and type of enclosure given the specs that you entered for that sub.  It just looks at a flat response of a Q at .707 if the situation calls for a sealed enclosure.  It doesn't care what your putting the sub in...a car, a house, a boat, a stadium...so you'll see that sometimes you'll get responses like 10 cu. ft. for a sealed and things like 5 ft for a port with some vented types.  This gives you an indication that oftentimes a speaker is not going to perform as well as it mathematically can within the confines of the environment you want to put it in.  Manufacturers of car audio are well aware of that restrictive environment, and so they will give you a "reasonable" range of enclosure sizes that you can use.  Home audio is much easier because of the room you have there, so you will see 8" subs in enclosures that car audio sometimes tries to fit two twelves into.  That make sense?

Who said a 12" sub will necessarily outperform a 10" sub?  I've build systems using a  6.5" sub that easily "outperformed" certain 12" subs.  It depends on how the speaker is designed and made, how it is being used, how it is aligned, how it is powered and Eq'd, and how it is installed.  Cone size, by itself, means nothing without taking many other factors into consideration.  It also depends on what you mean by "outperform."

I also own one of THESE, the Sunfire Super Junior.  Although it is not my favorite system, this subwoofer uses 6" drivers and produces bass output that measured in both frequency response and SPL rivals most systems using much larger drivers.  Size does not always matter.

***sighs of comfort***   Posts like this is what makes the12volt my car audio forum of choice.  The other forums are bubbling over with newb SPLers whose analysis ends at "cone area * xmax."