Okay. I know when I need someone smarter than me. I need some advise.

I installed a 10" DVC sub in the trunk in a ported enclosure awhile ago. It was okay, but I was using an old 4-channel amp bridged down to run it (had that one lying around). I recently replaced it with a Rockford 750.1 sub amp that I bought from a friend. Huge difference!

It sounds okay, however, when I open the trunk a little, the SPL increases by a factor of 10, and quality increases during music as well. Why would the trunk be drowning out bass response? It's like I'm starving it for air.

More importantly, what would you suggest to fix it? Any thoughts?

Thank you for your response.

 

Just a guess, but the trunk is probably acting as a resonator and absorbing much of the frequencies you want to hear. Try moving the sub box forward and back in the trunk to see if it helps. You're not starving it for air. Subs don't blow air, they just shake it back and forth. Have you tried turning it around so it faces the other way? I'm assuming you mean the SPL and quality inside the car increases, not outside the car.

 

Which way is the sub and port facing? without your trunk being completely sealed from the inside of the car i would have the sub facing you when you open the trunk. port to the side or also facing you. Are you in a garage when your doing this or outside? also i would and have taken out the stock subwoofer to open op that big hole and let the sound travel in. Thats my

 

I agree with tfe691 - Subwoofer waves are very long, so you want to give them as much room as possible. I did this in my old CL-S, and it made a huge difference (FYI - it was 2 JL audio 10"s, sealed, with a 400W Phoenix Gold amp). The bass was so deafening, I had the potentiometer turned to about 20%.

 

all good responses so far, just want to focus on one thing, who made the box for the sub. If it was not custom made IE sq. ft. matching the sub, and port diameter and length correct, then get a new box. Secondly, your spl can increase when you slightly open the trunk because you decrease the pressure in the trunk allowing the excursion of the cone to increase further. This will have two other effects, 1: if you open your trunk fully you should hear much less bass, and, 2ndly, NEVER play your subs loud with the trunk open at all. Because this causes the cone to over extend itself you will blow your sub asap. When wiring up a sub in a trunk you should have it face the rear license plate then reverse the phasing. If you do not reverse the phasing then the sound waves will be out of phase with your interior speakers when they bounce off the back of the car and enter the cabin. To reverse the phasing just switch the positive and negative backwards when the connect to the amp. Because cars are so very different in how they effect soundwaves you will need to play with the phasing, because the above is only a rule of thumb and needs to be specific to your car.