Hi love the forum, I have a 2004, SL55 AMG, I am interested in changing the stock radio for something else. An upgrade. Any recommendations as to what works? Is it better just to get a newer 2008-12 factory head unit, or go off factory and get a Alpine, Kenwood, Android, pioneer, or something else? Any suggestions would be much appreciated 😊 thanks! wadennis2@gmail.com or here on site or both!

Welcome to the forum. One great feature is the search button to find topics that have been discussed in great detail. If you have not used the functionality of the search feature, it's a great time saver with tons of information.

Your amplifier has an optical interface which is only compatible with '04 and earlier COMAND, so it will have to be replaced as well. And while a typical audio installation has a crossover on the speakers, with your car the crossover is in the amplifier.

If I were going to replace COMAND, I would get an '05 or newer factory amp and an ellectric-to-optical interface like this to work with my replacement head unit.

Hi!

I would definitely go with an android head unit. It works as radio, MP3 player, navigation,you can connect your phone to it...
And if it has a touch screen, even better.

Mario.

I priced out a complete replacement at one of my local shops. I was quoted about $3k, with a lot of that the work to construct a custom facia and the labor to rewire the speakers and amp. Bobterry's suggestion is also possible but certainly is not straight forward. I've purchased a MOST-compatible amplifier and mapped the wiring to replace my D2B amp. Still would need a MOST adapter and extension cable, along with a head unit and a custom-fabricated trim facia.

The good news is R230 amps from '05 - '08 cars are readily available on eBay, if not a bit pricey.

As others have mentioned, there are a lot of threads on this subject in the forums. Worth the time to do the research.

I also like the android replacement radio. Just beware, your fm reception will be garbage.

I missed this but there are trim faces readily available for aftermarket equipment as well as most adapters for the factory amp. Look around a bit or even do a search on this forum. Been covered many times.

I'm certain no amount of searching the forums will reveal an adapter for an '04 or older car, as none exist.
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https://www.installer.com/item/displ...php?it=ctkmb08

https://www.installer.com/item/displ...?it=most-hurmb

That unit explicitly states: "Must have a Fiber Optic MOST Amplifier." An '03 and '04 U.S. car has a Mercedes-proprietary D2B optical interface -- not MOST. AVIN USA offers the same product at a fraction of the cost.

That unit is not an interface to an optical amplifier of any kind: "CAN-Bus steering wheel control interface and Fakra antenna adapter w/ NO FIBER OPTIC AMP" {emphasis added}.

All you need to do to get the android radio working with your Mercedes is to buy the optional bypass cables. This allows you to tap directly into the speaker wires and bypass using the stock Bose amplifier completely. I also added a Rockford amp to run just the subwoofer. In the future, I will replace the stock speakers and add a 4-channel or 6-channel to run the doors and rear “fill” speakers instead of the head unit. I have an 03 btw.

There are advantages to keeping the stock amplifier.

There are no electronic filters of any kind on any of the car's speakers, since the desired filtering is done in the stock amplifier. If that is not addressed in a system using an aftermarket amplifier, then the door tweeters and rear speakers are fed audio frequencies which they can not properly reproduce (bass, notably), and these speakers will run hotter than they would otherwise. That unnecessarily limits how loud the entire system can play. To a lesser degree the above comments also apply to the door mid-range speakers.

Also, since the stock amplifier is bespoke to the R230, it is able to incorporate equalization and digital signal processing to enhance the sound quality specifically for the R230. I'd find those benefits difficult to replicate with aftermarket gear -- particularly if I am shopping on a limited budget.

Finally, the rear speakers are wired in series. With an electo-optical interface like the AVIN, no sound will play from the rear; there is only sound from the doors and the subwoofer. I have no idea if this is the case with a wiring adapter which interfaces a head unit directly to the speakers, but if there is sound, it is not stereo, of course.

The rear fill speakers are used when processing a surround-sound source. Not sure under what conditions the stock unit will make use of those rear speakers. I believe I have heard them used with FM radio reception, but I cannot confirm that.

If I understand what you are saying is that the only way to utilize the rear fill speakers are to either 1) leave the car completely stock, 2) for those with '03-'04 R230s upgrade to a '05-'08 system replacing amp and head unit, or 3) rewire all the speakers to an amp and head unit system that can utilize rear channel speakers at a less than optimized level.

A year ago I met with an audio guy who's shop specializes in high-end audio systems. He quoted me a number around $4k to replace just the speakers and amps - keeping the head unit. Another shop I spoke to quoted around $3k to replace head unit and amp, leaving the speakers in place.

That's an accurate summary, I think.

If you look at the architecture of high-end home audio systems, I think you'll see there is a left-front channel and a right-front channel. There is no sound coming from behind the listener. Also, with the stock system I have only discerned sound coming from the rear when I have chosen one of the spatial expansion options ("surround"), and I personally chose not to select any of them. Mindful of these points, I don't know if losing sound from the rear speakers with an aftermarket head unit is much of a loss at all.

Also, I'm of the view that if someone cares about music and having it sound really good, a car is a terrible environment for listening. While a home system costing $3000 or less can give the illusion of listening to a live performance, no car system I know of can accomplish that feat.

So, presuming the reason to alter the stock system is to upgrade the head unit (COMAND), then the objective is to spend as little money and effort as possible to have sound in the car. With an '05 or newer car, an AVIN-like interface which keeps the stock amp and speakers seems logical to me; but on an '04 or older car, I'm not sure. I suppose having the AVIN while integrating a MOST amp from a newer car is easiest, but possibly an aftermarket amp and either a filter capacitor on the door tweeters or new door speakers is best.