subterFUSE

This is an interesting issue, and I think it might have something to do with the fact that the factory system is Bose. Bose car stereos have always been unusual because they use non-standard impedance loads for their speakers. In addition, there might be some unusual Equalizing done to the Bose system. It is very common for OEM car stereos to have some factory equalization applied in an attempt to tune the interior of the car. This equalization can affect aftermarket audio equipment performace if you don't have any processing to undo it.

I had noticed that the amplifier you are using has High Level inputs built-in, but you also mentioned it was an inexpensive amplifier. My guess would be that it has little or no DSP processing to correct factory equalization. If that is the case, then it is entirely possible that the Bose system could be affecting things.

This could be a scenario where it might be helpful to have a processor in your system between the Bose amp and your aftermarket amp. Most aftermarket Line Output Converters and/or signal processors will have a calibration CD which is designed to detect factory stereo equalization and correct it. That way your aftermarket amps are feed a clean, flat signal which improves their performance.

Do you know if your stereo shop did any testing on the Bose amplifier signal to determine crossover frequencies? Do they have an RTA meter and oscilloscope?

Archieafroz

Guys... I have a question and while I was thinking about the Question, I thought it was dumb to even ask but I am going to to. Sorry in advance.

I have read the whole thread and it seems like AudioControl LC2i does a pretty good job. I have the 2012 C7 and while reading about the AudioControl LC2i, I interpreted that this AudioControl LC2i can be added to any "Stock" car music system.

AudioControl LC2i requires an Amplifier and a Sub-woofer. The C7 has both (correct me if I am wrong). The question !!

Can I just add AudioControl LC2i to my current BOSE system...? No new Amplifier, No new Sub-woofer. Only adding a AudioControl LC2i module.

Will it work...? (Call an idiot if you want Better someone calls me one here then the real world)

Thank you

subterFUSE

The answer is No. The AudioControl LC2i is simply a converter. It is not an amplifier, so it cannot drive any speakers directly.

The purpose of the LC2i (and any other brand of line converter) is to allow integration of aftermarket audio components to modern cars where it is no longer practical to replace the source unit in the dashboard. Back in the old days, car radios were very simple boxes that could be taken out of the dashboard without affecting any other components of the vehicle. But in today's modern cars, the stereo units are often molded into the dashboard permanently and include air conditioning or other controls. The option of removing the source unit in a modern car is very limited. The aftermarket car stereo business had to adapt. The line output converters are just an adaptation the industry made to be able to upgrade audio in modern cars without having to replace the source units.


The line converters work by plugging into the amplified signal from the factory amplifier. They convert this high level input into a low level preamp output which can then be used to feed aftermarket devices. You retain full use of the audio controls in your dashboard, while getting the advantage of adding your aftermarket equipment like DSP processors, Amplifiers and speakers.

Some line converters are very simple, while others can be highly complex DSP processors. Your overall system design may dictate which kind of converter makes most sense.

One thing which I have pointed out before which should be repeated, Bose car audio systems are notorious for being quirky when it comes to adding aftermarket audio. Bose is a company which does not follow the most common design norms for their equipment. For example, most car audio speakers are built at a 4 ohm impedance. Bose speakers are often lower impedance than that. Many OEM audio suppliers, Bose included, also will EQ their systems to give them a distinctive acoustic profile. This may be a nice thing for the OEM equipment, but when adding aftermarket gear you don't always want their EQ coloration.
For these reasons, I would generally recommend selecting a line converter which has some DSP processing onboard that can de-equalize the factory audio signal. Some examples of these DSP units would be the Audison BitOne, JL Audio CleanSweep, and JBL MS8. Each of these includes a setup CD which you play in the car and it will calibrate the DSP to correct any equalization to the factory stereo.

Archieafroz

Thank you so much. Makes sense...

S6Express

I just installed a 12" sub and RF amp via line output converter to the signals going to the passenger front door sub and the rear parcel shelf sub on my B&O system in my S6.

My 12" sub is generating a real annoying buzz/hum from the system and feel like it's being generated by the ANC.

What do you guys think I can do to eliminate that noise? Disable ANC? Use a different signal? I need help.

Thanks.

subterFUSE

What are you using for volume control?

simplysukh

Great read, this sounds great.

I have a 12" Rockford Fostgate T1 at home from my previous car.

My concern is will there be any boot rattle or any distorted noise outside the car from rattling number plate or anything?

can someone who has installed a sub shed some light on this please

subterFUSE

High output bass will cause rattles.

Sound dampening can be applied to metal panels to keep them from rattling. We're going to be dampening just about every inch of my car from floor to roof, trunk to dash.

S6Express

I've confirmed the noise is being created by the noise canceling system in the car's b&o system. When I roll the front windows down halfway the noise goes away and it sound like a normal sub. I didn't buy a new loc because the noise is being sent to any loc I put in place. So question is: is there a way of switching off the noise canceling by making the car think the windows are down?

subterFUSE

Have you attempted to disconnect the ANC microphones?


My car is still in the shop for my audio install. We are not far enough along yet to test this, but will be soon. I'll report back with whatever we find.