Troubleshooting Cancellation in my 09 Jetta.

Bwcad1 · Post by **Bwcad1** » Tue Aug 17, 2010 9:43 am

what were you trying to gain with the downfire.

CaptainPioneer · Post by **CaptainPioneer** » Tue Aug 17, 2010 9:55 am

The ability and carelessness to just throw shit into my trunk without the possibility of hitting the subs... lol

JeremyC · Post by **JeremyC** » Tue Aug 17, 2010 10:23 am

I've always had the best experiences down firing in trucks where the speaker is in the same area as you.

Never tried it in a car, but I can see how it would be problematic. Especially if both the front and back of the enclosure were open, allowing the sound wave to go both directions.

If your enclosure is open on the front and the back, try blocking one of the two. You might even try swapping what one is open (same thing if only one side is open, try spinning the box)

If neither helps, then your best bet is going to be a new box.

If you don't mind giving up some trunk space, build a baffle to seal the subs to the back side of the seat. I'm guessing thats what bill did to his car. That will stop any of the sound wave from hitting the back of the trunk and canceling out once it inverts 180 deg.

If you can't do that, you next best option is firing back, or mounted to the sides firing cross. Mounted to the sides will open your trunk up, and does sound pretty dang amazing, but it is a lot of work.

CaptainPioneer · Post by **CaptainPioneer** » Tue Aug 17, 2010 10:43 am

I actually have another box built for what was supposed to be my Eclipse 12" subs when I had the 07 Camry... It's still in my basement... If it turns out that i have to re-outfit the subs in a new enclosure, I'll try that one first... Its considerably larger but I think it should work, as in the case with my last downfire box in my truck... bigger and better sounding...

I think Autotek may have it wrong with their recommended box size... my enclosure is tiny

Bwcad1 · Post by **Bwcad1** » Tue Aug 17, 2010 11:02 am

CaptainPioneer wrote:I actually have another box built for what was supposed to be my Eclipse 12" subs when I had the 07 Camry... It's still in my basement... If it turns out that i have to re-outfit the subs in a new enclosure, I'll try that one first... Its considerably larger but I think it should work, as in the case with my last downfire box in my truck... bigger and better sounding...

I think Autotek may have it wrong with their recommended box size... my enclosure is tiny

They dont. They were built just for that purpose. However i had the 12's in 1.8cf in my sealed bandpass and i was looking for much more lower end.

Jeremy is right about how i did my box.

Just some simple modification can fix it. Add a back to the bottom of the box and sides so just the front of the box is open and then just make some cheap baffles around the box from 1/2 mdf and cover with carpet should work just fine.

CaptainPioneer · Post by **CaptainPioneer** » Tue Aug 17, 2010 11:44 am

I feel like I'm loosing a lot on the low end in my current box enclosure... the possibility though may be the fact that I'm using a LOC.

I will relocate first then if it doesn't seem to get me where I'm going, I will try my other box which is bigger... and see if there is an appreciable difference.

Bwcad1 · Post by **Bwcad1** » Tue Aug 17, 2010 12:02 pm

CaptainPioneer wrote:I feel like I'm loosing a lot on the low end in my current box enclosure... the possibility though may be the fact that I'm using a LOC.

I will relocate first then if it doesn't seem to get me where I'm going, I will try my other box which is bigger... and see if there is an appreciable difference.

you may need to use an auto summing module like the LC6i. You may not have a full frequency input into your amp. For instance my Buick factory radio crossed over each channel before amplifying it. So my front speaker out put rear speaker output tweeter and rear mid range speakers all received the specific range they were ment to play. I had to sum the Front Speaker Tweeter and Rear speakers in order to get one full range output. Was a pain in the dick.

The small box is probably recommended and sounds decent but is also designed to protect the sub. that's y no body ever goes with factory specs anymore... lol

CaptainPioneer · Post by **CaptainPioneer** » Wed Aug 18, 2010 8:47 am

Well I took into consideration everything that was recommended and success i have substantial bass now... here's what I did.

I first moved the subs all the way to the back of the trunk where the lid opens.
then, fired them up Tuned the amp a bit and voila! Its sounds much better.

Still low end is suffering anything below I would say 100hz... (Estimation please don't castrate me over that)

So I think like bill said the problem lies in the source... I doubt the LOC is actually restricting frequencies, and I did tap into the bass speaker in the rear which is the only one that would give me the full range of frequencies. I believe that either the amps for the car or the HU may have a built in lowpass filter not allowing signals to be transmitted below a certain hz...

If this is the case I may end up purchasing a Pioneer AVIC D1 or D2...

Jason

Bwcad1 · Post by **Bwcad1** » Wed Aug 18, 2010 10:03 am

CaptainPioneer wrote:Well I took into consideration everything that was recommended and success i have substantial bass now... here's what I did.

I first moved the subs all the way to the back of the trunk where the lid opens.
then, fired them up Tuned the amp a bit and voila! Its sounds much better.

Still low end is suffering anything below I would say 100hz... (Estimation please don't castrate me over that)

So I think like bill said the problem lies in the source... I doubt the LOC is actually restricting frequencies, and I did tap into the bass speaker in the rear which is the only one that would give me the full range of frequencies. I believe that either the amps for the car or the HU may have a built in lowpass filter not allowing signals to be transmitted below a certain hz...

If this is the case I may end up purchasing a Pioneer AVIC D1 or D2...

Jason

A LOC is not a crossover or eq and wouldn't modify the signal. My guess is the factory audio is limited after 100hz to protect that shit factory speakers. My Buick would do that once you reached a certain volume it would start attenuating bass to limit excursion on the speakers. the small box size is also probably limiting you a bit but with the power your using i wouldn't go any bigger.

CaptainPioneer · Post by **CaptainPioneer** » Wed Aug 18, 2010 11:43 am

So the real solution is a HU and if I deem necessary a new box design... I have turned the gain down on the amp significantly and has improved the overall bass experience quite a bit...

I'm looking into the Pioneer AVIC X910BT... looks like everything I would want in a HU...