Stereodude

I'm not assuming anything. Your 6 channel processor doesn't have enough channels to capture all the audio coming out of the factory radio. Whether you want to use a similar number of speakers or not is up to you.

I don't think anyone has marked you as a pariah. However, your approach seems questionable regardless of your credentials an an employee of Sirius XM. If you really just care about audio quality keeping only the front sound stage with discrete amplification, active crossovers, and time alignment would be a better solution than what you're planning.

StasisS4

Face push!! I guess thats what happens when you name drop your audio credentials... Pretty hilarious.

Evlengr

Hmm I thought that is what I just said. Wasting my time here. Not here to argue with you just trying to find out simple measurements for the door speakers that was it.

I would have done it myself but the vehicle is on order.

If you don't know, just say you don't know.

Ah well such is life.

Stereodude

Good luck! I don't expect you'll be getting any help here from anyone with that attitude.

PS: That's not what you just said. You said, "I will be using the doors only and the rear deck". There are full range speakers in the rear deck.

RobC

Coming from high-end home audio, I can appreciate your requirement for precise imaging, detail, dynamics, and timbre.

In my (early) 2010 B&O system, I found that there was a very apparent phasiness (out of phase) to the sound and especially the low end when the DSP soundstage was set to ALL. I prefer the sound when the soundstage is set to FRONT. The missing bass comes back, the sound is much more coherent, and the soundstage and imaging are greatly improved. I've no idea if this was addressed in later models, and the S6 B&O system I heard (at the car show) didn't suffer from this when set to ALL.

I'm not able to answer your question about speaker sizes, but I did want to give you some food for thought about speaker replacement. In my previous B5 S4 with Bose system, I'm fairly certain that the Bose amplifier had active filters to shape the frequency response of the system. I suspect that the same might be done in the B&O system (and especially easy with DSP) and simply swapping the main speakers may not result in the sound improvement that you're expecting. The only way to be sure I suppose would be to do a frequency response plot of the electrical signal feeding the speaker. I have the tools and means to do this, but I don't particularly want to take my doors apart :P.

jhartm2

Hooray for RobC for a useful response. Too many trolls wandering around these days, obviously everyone has their own tastes with their vehicle and a little respect really shouldn't be that hard to show others.

+1 on the active filter side, messing around with those on my B5 A4 cost me entirely too much time for the sound I wanted... guess I needed a better toolset, but it sounds like the OP may have that covered.

Dr Chill

Has anyone mentioned that B&O is a really nice upgrade over the standard stereo?

Evlengr

Thank you Jhart and RobC. I didn't realize asking about something as simple as speaker size would create such stir. I asked for an objective response (measurements) and got many subjective (quality) responses. The question was not asking if the B and O was better than the original system. It was simply asking about diameter and depth because I like to plan ahead and have things ready and in order for when the vehicle arrives.

I ran into this kind of attitude when I first changed out the sound system on my BMW. I now have a permanent sticky on Bimmerfest that myself and many members contribute to further enhance the quality of the X3.

I plan on bypassing all the electronics except to use the H/U as a controller/pre-amp set up. The new set up will hopefully include my Boston Acoustic Reference component speakers for front and back as well as a low profile dual voice coil 10" sub for the rear deck. The audio control elec component will be at the heart of this system and driven by Alpines newest 5 in 1 amp. It is a D class amp so very low profile and not as susceptible to heat issues as many amps.

I'm sure the B & O is a great system as they are a great electronics company, but part of the fun for me with a new car is changing the sound system and tailoring it to my tastes.

When I get the S4 I will take measurements, pictures, and do some DIY videos for future questions.

Thanks again guys.

RobC

I'd be very interested to find out how the outputs of the stock HU are implemented. In a previous non-Audi car, the headunit had differential low level outputs, so I had to build my own diffamp to convert to signal ended to use with aftermarket amps.

I've heard of some cars using class D amps with a digital signal straight to the amp. For your sake I hope that's not the case for the B&O :P.