Tcguy85

i always knew it sounded like there was a slight difference in bass response with the roof open and closed. so here is a chart of the sub-bass response in my car with it open and with it closed. there is a 7db difference at 20hz, a 5db difference at 32hz, and a 2db difference at 40hz. at 20hz and 32hz those are pretty big jumps with it open, the 2db jump at 40hz is a small difference but it's still there.

for those that don't know, i have a single ten inch ported sub tuned to 30hz. it's placed on the left side of the trunk firing to the side.

here is the chart

mike6789k

pics of sub plz?

Tcguy85

i want to keep this on topic but here ya go just for reference...

mike6789k

oohh yea that one! noice man

but yeh i mean obviously you'll get different sorts of resonance if you open / close the sunroof or windows.. hey since you have this fancy rta tool why dont you figure out the optimal window / sunroof position for most boost around 30hz :D

nodsetse

This isn't the case with all cars or systems, and I'm somewhat surprised of your results. There's almost always a trade-off in this scenario, where some freq's are boosted but others are lowered. It's also counter-intuitive/illogical, when considering SPL and the way mics work, sealed car should produce higher dB. Oh well, as long as you're happy with it that way...

Edit: Using a cheap SPL meter, when I open my sunroof, I lose dB. That's not frequency specific, but makes sense because the mic isn't seeing as much pressure.

Dr_Isotope

iTrader: (1)

I've gotten better response with the box on the opposite side of the hatch, and I notice a dip in bass response with the sunroof open (pair of 10s, sealed), so I think as nodsetse said above, results will vary from app to app.

Guanato

i'm gonna try that

rmp21115

i knew it!!

SupraSpeed

think of your car with the sun roof open as a huge ported sub box. viola

looks like you got a nice sounding sub though from what i can tell of the frequency graph =]

Tcguy85

yup, it sorta turns the car into a huge bandpass box in a way.

and yes, i love my sub. sounds sooooo good.