The factory audio system is bad enough that the bass is improved (marginally) by one of the rear channels going to a sealed box with Qtc~1.44 and Fsc~100Hz.
The car in question is a 2002 BMW 325xi Wagon (Touring). I am having trouble finding the internal volume of the car online, and even if I could find it, I don't know how to calculate what kind of "room gain" I'll get from the cabin. I have a lot of space available above the spare tire, and was hoping to poke something in there.
One other idea I'm toying with is a small box (4L) with 8 Dayton PA130 drivers (Qtc~1.5, Fsc~300Hz), and a 2nd order 30Hz butterworth lowpass on the input to the amplifier.
Any ideas?
The car in question is a 2002 BMW 325xi Wagon (Touring). I am having trouble finding the internal volume of the car online, and even if I could find it, I don't know how to calculate what kind of "room gain" I'll get from the cabin. I have a lot of space available above the spare tire, and was hoping to poke something in there.
One other idea I'm toying with is a small box (4L) with 8 Dayton PA130 drivers (Qtc~1.5, Fsc~300Hz), and a 2nd order 30Hz butterworth lowpass on the input to the amplifier.
Any ideas?
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I'm afraid I have no idea what you're talking about, but a quick search says something about a Keystone sub? Is that some variation on a horn?
I was thinking of trying to put as large an enclosure as I can fit above the spare tire, with the speaker face 5cm below the surface of the trunk, then put a trunk floor above it with vents on the side to make, essentially, a slot-loaded sub.
I was thinking of trying to put as large an enclosure as I can fit above the spare tire, with the speaker face 5cm below the surface of the trunk, then put a trunk floor above it with vents on the side to make, essentially, a slot-loaded sub.
Well, the answer to the room gain question is - ALOT. From cars.com, I find 106 cubic ft volume...so go from there.
So, 106 cu ft. Cool. Now what? I've tried researching room-gain and all I can find relates to dimensions and whether there's room for a complete wavelength in the room or not. Since there won't be a complete wavelength, I figure room gain will be defined more by volume than by dimensions, but I have never actually found any references on how to calculate it. I'm sure I'll have less cabin gain than an MR2 would, but...
Cabin gain is approx 12db/octave below a frequency determined by the longest dimension of a space. As far as dimensions for the sub a quick tape measure trip through the cargo area will help.
Have you considered output levels required or power available?
i know that 2 8" in a 1cuft sealed box will hit 120db at 30hz in car.
As far as hearing damage as frequency drops aceptable output increases rapidly towards 140db at 10hz. Not comfy but not dangerous.
Have you considered output levels required or power available?
i know that 2 8" in a 1cuft sealed box will hit 120db at 30hz in car.
As far as hearing damage as frequency drops aceptable output increases rapidly towards 140db at 10hz. Not comfy but not dangerous.
Existing speakers run off the head unit, and are 2 ohms, so probably ~25 watts. I think the system is plenty loud, but it has too much midbass and not enough low bass. My previous car was a Saab NG900, and I had TB W6-1139si subs in the doors, off the stock amp. That was plenty of sound and sounded pretty good, but it was also a much smaller space.
Is the slot-loaded under-floor option feasible, or am I better off just going with a sealed box? Thinking I can make a fiberglass sandwich with sonotube in the middle for the sides of the box, and screw that to a plywood plate at both ends to drop into the spare tire area. I'll measure in a few hours.
Is the slot-loaded under-floor option feasible, or am I better off just going with a sealed box? Thinking I can make a fiberglass sandwich with sonotube in the middle for the sides of the box, and screw that to a plywood plate at both ends to drop into the spare tire area. I'll measure in a few hours.
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