Sound quality dropped when changing vehicles

[aharper 10+ year member]

I’m having a problem with sound quality from a subwoofer and am hoping that someone can help me fix it.

I used to have a 2004 Suburban with a Pioneer headunit (subwoofer out, eq, etc) feeding a JL 500/1 amp pushing a 12” ARC subwoofer. Amazing… I could run at nearly any volume and the quality really sounded great. Nice tight low bass that was perfect for bass guitars, etc. If I played more aggressive music loudly it was hard enough that it would darn near effect my vision. Weird, I know, but worth mentioning because it was deep, clean bass.

I moved the amp and sub out of the Suburban when I sold it. In its place I now have a 5 series. The iDrive in the 5 series doesn’t allow for easy integration so I’m using a LOC that is tapping into the wires leaving the factory amp that run to the factory subwoofers under the front seats. The LOC converts to RCA’s that feed that same 500/1 amp with the same 12” ARC subwoofer.

Sound quality is terrible. It’s “loud” and punchy but has no real meat to it. I’ve tried some tweaking of settings on the amp but end up back to very close to where I was. When playing music that used to sound super clear with a clean, tight, carry in your gut feeling it’s now loud without any deep sensation at all. Very difficult to write out, it’s just not the deep sound that I enjoyed with every day music in the Suburban. I don’t normally listen loud, but I like the clean sound of deep quality bass. The subwoofer sits in my trunk facing into the ski pass into the cabin.

It’s been a long time since I’ve used a LOC, and this is my first 5 series with the iDrive. I had an older 5 series that didn’t have this same integrated radio and I got clean sound out of it. This car is just leaving so much to be desired. Nevermind that the highs need addressed as well, I’m just focusing on the lows right now because I already have the equipment. Other 5 series owners are talking about having good bass but I don’t have anyone nearby to allow me any real testing with the equipment.

My worry is that the amp may be filtering lower signals, say below 100Hz. This just doesn’t make much sense to me sense there are subwoofers that are getting the signal that I tapped into. I’ve gone so far as to remove my front seats to verify the wiring going into the sub just to be sure I’m in the right place. I also took some twisted pair RCA cables and tapped those directly into the location of my LOC because someone said that I didn’t necessarily need it. I get the same quality either direction.

Please help!!! I’m sooooo missing quality sound!!! What can I do to get low lows back again?

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[chillin 10+ year member]

It may not have that deep sound because you are aiming the sub into the cabin. Try turning the box around so the waves bounce off the back of the trunk first.

 

[jco1385 5,000+ posts]

maybe because of the considerable air space difference?

 

[aharper 10+ year member]

I'm thinking air space as well, I'll turn it around and fire the other direction tonight to see what happens. If air space is part of the problem would dropping my speaker size help? Maybe drop down to a good 10" sub or a couple of 8's??

Going back many years... had 3 8w6's in a smaller car that were amazing. To save space I dropped to a single 10w6 and had darn near the same quality. Thoughts?

 

[aharper 10+ year member]

I'm thinking air space as well, I'll turn it around and fire the other direction tonight to see what happens. If air space is part of the problem would dropping my speaker size help? Maybe drop down to a good 10" sub or a couple of 8's??

Going back many years... had 3 8w6's in a smaller car that were amazing. To save space I dropped to a single 10w6 and had darn near the same quality. Thoughts?

 

[Bumpin' Goalie 10+ year member]

Stock radio, etc? You may be lacking signal at the lower frequencies. Some radios will have a roll off to protect stock speakers, etc.

Once again, not all, just some. Might be worth looking into.

 

[tpmeredith 10+ year member]

I don't think dropping speaker size will help with airspace problems, seems like it would be something else. I mean you are going from an SUV with massive space and no blocking to a trunk car which can stop some bass

aiming into cabin is always a last resort if you cant aim it any other way, best is back or up

If your amp was 'filtering low signals below ~100hz' you would have almost zero bass coming from your sub, it could be that your LPF is way too high but that's doubtful

"LOC that is tapping into the wires leaving the factory amp powering the factory subwoofers"

The car has a dedicated factory subwoofer amp, correct?

I'm not sure but it seems like you'd want to bypass that amp completely,

Beyond that I'd say if all of that advice doesnt work... get an aftermarket HU

 

[aharper 10+ year member]

I can't bypass the amp because I'm not sure how it is getting it's signal. The iDrive dealio is a headache to deal with, BMW doesn't play nice with allowing customization. The amp is also driving another set of speakers along with the factory subs, I'm assuming the rear deck.

 

[jco1385 5,000+ posts]

if it was mine, i'd grab an aftermarket HU and some wire and re-wire the whole **** car. i hate **** like that. hell, i didn't have all that to bypass and i still re-wired the whole car.

 

[Imtjnotu 5,000+ posts]

air space may be it....turn it towards the back anytime u have subs in the trunk unless u are willing to seal the trunk off.....also how is the voltage...

 

[hispls 5,000+ posts]

Probably just the acoustics of that car. You can experiment with position and aiming of the box but from my experience those German luxury cars are tough to get good sub stage.

 

[Rudy 10+ year member]

You don't really know if it is the signal or the vehicle acoustics. Before I did anything, I'd try a different source - iPod or something directly into the amp. If that sounds good, you'll know the signal is the problem.

 

[tpmeredith 10+ year member]

You don't really know if it is the signal or the vehicle acoustics. Before I did anything, I'd try a different source - iPod or something directly into the amp. If that sounds good, you'll know the signal is the problem.

This^^

I'm willing to bet it's the install IMO

 

[tpmeredith 10+ year member]

if it was mine, i'd grab an aftermarket HU and some wire and re-wire the whole **** car. i hate **** like that. hell, i didn't have all that to bypass and i still re-wired the whole car.

Same here bro, I hate all "Premium" sound systems. My friends 99 maxima came with a bose system and it's a pain in the ***. It worked fine for a few years with an aftermarket HU and all kinds of adapters but recently a fuse blew and wont stay on without blowing, and his HU works fine and stays on, just the speakers / bose end doesn't work. All pain in the ***** IMO

 

[morespl 10+ year member]

Your facing the sub into the cabin is the first problem. My buddy had a lincoln ls with a soundstream xxx 15 and it sounded week the sub was facing forward. If you have no back pressure the sub doesn't play how it should.