I had an 2005 SL55 and traded for a 2013 SL63, but have been disappointed with the radio sound system. I think the quality of the speakers are OK, but the sound is no where near the quality of the Bose system in the SL55. Has anyone made any upgrades to this HK stereo system--added a power booster, changed speakers, etc? Thx.

you should have got the B&O system

Ok, thx for input. Got performance pkg, driver's assistance and premium pkg, but not B&O or ceramic brakes.

I can upgrade stereo and looking for input, not "should've" bs. Very happy with my CPO.

I'm sure some have.

Your best bet is just stop by a couple car audio shops in your area and tell them what you're comfortable spending and see what they can do for you. Today's car audio systems are very complex and you need someone with the knowledge of what you can and can't do.

I had a 2005 SL600 with the Bose system, the same as your SL55. I also have a 2009 SL600 with the HK system. I realize your 2013 is an R231 but I will come back to that.
Sitting in the garage with the systems adjusted to my taste I found the HK system in the 2009 sounded better than the Bose system in the 2005. This was with CD's as the source, not some compressed and frequency truncated satellite radio channel. Driving on the highway at speed the systems were indistinguishable. I have sold the 2005 and now have a 2017 SL65 with the top end B&O system. Again, sitting in the garage with a good CD as the source the new B&O system is much better than the HK system in my 2009. But driving along I-5 with the cruise at 70 the systems sound vurtually the same with the ambient road noise in the SL. Unless you are spending a lot of time in stop and go traffic I see minimal benefit to upgrading the system based on my actual driving experience in the SL. If you listen to a lot of satellite radio it is definitely not worth it.
If you really want top end sound you need an S class with the Burmester 3D system. The SL is a great car, just put the top down and enjoy the rumble, cracking and backfiring of the exhaust system.

While I haven't heard the HK system in the SL, the HK in my 2005 C55 is decent.

The Bose in my 08 SL is better than the HK, WITH EXCEPTION to certain frequencies in the low range bass. The SL COMPLETELY falls flat on it's face in certain frequencies, and it's incredibly noticeable (to me at least).

The HK in my 2015 Grand Cherokee is amazing. Except that every so often something doesn't start up right and the entire sound is like an old low quality MP3.

Good input; thx! One thing I really notice is the sound in the SL with HK is heavily weighted toward front of car and there isn't a front/rear adjustment that I see, lust left/right, bass, treble, etc. The SL is not a daily driver, but I may take it to a local audio store to see what they suggest--there is an outstanding one in town.

Hopefully the local store can work out an upgrade for your SL. The HK does not have an adjustment for front/rear volume but it does have the Logic 7 surround feature. In mine the system is front heavy with the surround system off. Turning it on moves the driver to the center of the sound field. There is a significant difference in sound and at least to my ears reduces the front weighting. Not the same as an actual balance control but it is an improvement.

Yes, I experimented with the Logic 7 and agree; it's better on. Just not used to lack of sound from the back. Guess it goes back to my old Jenson Triaxle days with boxes.

There are no speakers in the back except for 2 surround sound fill speakers. You have a center channel speaker in the front dash, woofers and mid-range speakers in the doors, the two fill speakers in the rear and a sub-woofer in the passenger footwell.

Roger that. Definitely and odd setup. Thx.

Read about the two different systems in this press release: https://media.mbusa.com/releases/rel...edes-benz-sl-1

in my experience the B&O system is superior to the HK system and both are superior to Bose. As for rear speakers I find it interesting that when we listen to music at home we generally have it coming at us from the front unless you are using a home theater surround system which defeats the purpose of a soundstage like from the old 2-channel stereos. We have gotten so used to having surround sound everywhere including our cars that the forward biased systems in the 2013 and newer SLs sound odd to us and unsatisfying. I have found the MB Sirius XM hardware to be noticeably lacking compared to some other vehicles that I have been in and own that sound as good as high-res MP3 files, because they have better hardware to receive and decompress the satellite signal. But nothing sounds as good as an original CD. The problem is most vehicles don't have cd slots anymore so we are forced to listen to low and medium res sources such as compressed MP3 files or even more compressed SiriusXM. Spotify and other streaming services do have HD quality options for a premium price. If you copy your own CDs onto a USB stick or SD card for your vehicle, you can choose hi-rez copy options on your computer before starting the copying process, which yield larger file sizes but with flash drives offering hundreds of megabytes that's not an issue anymore.

Thx for the info; makes sense!

I have a S63 with optional Bermister 3D, $6500 stereo. Its pretty good. But I notice alot of quality difference in the sirius sounds, and the HD FM channels , and the web, iheart and other web stations.
The sirius is dead and poor quality, compressed. While the HD sound opens up and has presence, like a cd.