Base stereo upgrade - Full range output

[TechieCarGuy]

I've been fighting with an install in my 2010 135 with base stereo option for over a month. I was working under the assumption that I could get a full range speaker level single to my Audison Bit-One from under the seats, but after fighting with this install for way to long have come to the assumption that whatever I have tapped into is not full range.

I am feeding the signal from what use to go to the 6.5 midrange under the seats into my Bit-one and allowing the Audison to De-Eq the signal. The 3 way separates up front sound amazing, but no matter what I try I have had no luck getting my subwoofer working. After first thinking I had two blown woofers, I moved to the amp, but all are working fine.

Today, I went so far as to swap out six different pairs of RCA's going from the Bit-One processor to my subamp thinking is was the RCA but each time I have the same thing... I can hear the sub, but its as if the signal is majorly attenuated. I even bypassed my subamp and plugged in a Velodyne home subwoofer in my trunk and had the same results, so have determined that everything below about 70 hertz or so is rolling off someplace and not offering any sort of low frequency output.

Everywhere I look online indicates that there is a fullrange output under the seats, but I am doubting this is the case. I am in the process of tracking down someone who can recode my car to Hi-fi in hopes that doing so will change these outputs to a low-level full range, but I am puzzled since every source I find online indicated that under the seat was full range.

My next step is to take the rear speak outputs and feed them into the Bit-One and let it De-Eq all four channels,er maybe that will work....

Has anyone else had experience with this? Did I misread all the post I read about the Base Stereo options? or am I just missing something simple?

[Dackelone]

I think you need to "code" the radio to change it's output signal. Its the same when you upgrade to BMW's Alpine HiFi audio amp & speaker kit.

Perhaps Technic or Patrys@BimmerTech can help.

Dack

[iminhell1]

I swapped my base speakers (no tweeters) in the doors to the premium ones. The mid in the door of the premium has a 'bass blocker' (capacitor) built in. That way it does not send the tweeter low frequencies.
The odd thing about when I did this swap was that I lost most of the output from the subs. I had chalked it up to loss of power because now I'm driving 2 more speakers on the same channels (6 vs 4). But now that you're finding issues also maybe I'm wrong. I'm wondering now if the output frequency range is based on feedback resistance?
IIRC there is a 'distortion circuit' involved and those tend to be based on return resistance. Maybe adding resistance to the circuit causes the reduced frequency output, low being the highest consumer of power and most often distortion.

[TechieCarGuy]

I have swapped out all my speakers with new ones, and ran my own wires to each location from the trunk where I have a 6 channel amp installed. The new speakers (8, 4 and TW) all sound fine and with the 8-inch crossed over at about 70 hertz inside the Audison all sounds fine from there up... its just the output for my subwoofer than gives me pause. Thus my assumption that the signal under the seat that I thought was full range, obviously is not. I have my tweeters xover using the Audison from 3500 Hz and up, my 4-inch mid between 110-3500 Hz and the 8-inch midwoofer from 70-175hz.

I tend to agree that coding may be the best solution, although I am worried about the expense. I will not consider the dealer due to the inherent cost associated with them and my independent, while extremely capable has never coded for audio and will charge me for the time it takes for him to find the module in the software. While I have read several post of coding for the Alpine Hi-Fi, I'm not confident even if I printed those post out my independent could find the right places to change settings without a ton of trial and error.

[TechieCarGuy]

Since I don't have anyone in my area who can reasonably code my system to Hi-Fi I have continued to try to address this issue through other methods. In the end I fear I will have to pay someone to do it, or drive a couple hundred miles to find a regional club member who can do it.

After attempting to reconfigure my BitOne and De-Equalizing the outputs from the factory head unit I have come to the conclusion that the Base stereo significantly attenuates all frequencies below about 70 hz. When I connect my subwoofer I can hear bass very faintly coming from the speaker but no amount of adjusting the subwoofer amp, settings in the Bitone or anything else will produce any results.

Considering I have not come across anyone else having this problem when upgrading the stock system, I am a little surprised. Normally I might expect such setup from an OEM, but considering our cars are getting more than 5 years old now (or more) I am surprised no one has discovered this before. Either this is the case, or three different (brand new) subwoofer amps on my part have been bad, which seems unlikely.

[tracer bullet]

I wouldn't call it common knowledge but it's been discussed that the factory head deck in the base system does some interesting things. Here's one of the first posts I've found on it, I think you may find it helpful. At least to confirm what you are seeing, if nothing else.

http://www.1addicts.com/forums/showthread.php?t=338597

[Dackelone]

VP Electricity knows what he is doing. After all he does run a stereo shop in the Pacific NW. He could code your HU Quart & iminhell1

There are also vendors over on the e90post that can do remote coding like Patrys@BimmerTech or bmwretrofit

Dackel