Programming the Volvo SC-816 Stereo

and still trying to find out about some of the mystery settings.

This document last modified January 24, 2006.

There were a few things that got me started on this subject. First of all, the standard Volvo stereo in the US spec cars sounds pretty nasty relative to most audiophile quality systems -- way too much bass, and the overall sound quality lacks presence and definition. I actually did some frequency response testing and found a huge 20 db peak centered around 60 hz. That's equivalent to turning the bass knob all the way up on your home stereo, and it's obviously why the US-spec stereos in the S70 models sound so much like those aftermarket stereos that urban teenagers like to put into Honda Civics to share with you at traffic lights. Some of that sound quality has to do with the stock US-spec speakers, and I've since done something about that. More on that within a week or so. Stay tuned. (That's a little radio joke, by the way. Get it? "Stay tuned?" Anyway....)

One of the things that I once read in some Volvo literature about the audio systems is that "every radio has a built-in equalizer where the sound curve from the deepest bass to the highest treble is set separately to suit each individual Volvo model." (This was in a long-gone Audio Options brochure from from Volvo's Swedish web site -- it was in English. This document covered radios similar to ours which are found in the European C70 models, so I'm going to assume that this statement extends to the US-spec radios as well.) To add to this, my '99 Owner's Manual describes a five-band graphic equalizer that's built into the (then) top of the line SC-901 stereo, and that equalizer has preset curves available for the S70, V70 or both C70s. Those preset curves are selected by holding down one of the preset buttons while powering up the SC-901, but there's no similar function described for the SC-816 in my car. Bummer!

Furthermore, the manual states that the SC-816 does have automatic loudness compensation as well as "automatic sound compensation" (ASC). Loudness compensation is a term typically used to describe boosting bass and treble frequencies at low volume levels to compensate for the human ear's natural insensitivity to those frequencies as sounds become softer. Most mid-range or better home audio systems have a switch for such a feature, and many car stereos do too. Our Volvo stereos apparently do not. The manual does describe a way to turn the ASC function off. It sure would be nice if there was a way to turn off the loudness, as well.

But maybe there is....

Several times recently, the subject has come up in a Brickboard forum that there was some undocumented functionality built into the controls of the SC-816. In summary, holding down the Chgr button while powering up the stereo allows you to switch between "stereo reception compensation" modes SRC1, SRC2, SRC3 and SRC4. I've since seen a Volvo Service Bulletin for the SC-815 stereo -- very similar, also with AM/FM/Cassette and CD -- which explains the use of a three position switch on the bottom of the stereo that allows you to switch between low, normal and high multipath sensitivity. (See the Volvo Service Bulletin for the 900 series vehicles 3-39-939, 10/95.) I can only speculate that this gives the equivalant of a high-frequency stereo blend function that I've seen on some other tuners. The idea is that, when reception gets weak, if the tuner designers minimize the stereo separation at high frequencies, they can make the tuner slightly more selective. This speculation is supported by the description of these three settings on the SC-815 service bulletin:

L = low multi-path sensitivity provides high stereo reception. Recommended in flat areas. (JR's note: I have a feeling that the word "reception" should have been translated to "separation.")

N = Normal Position. Factory Setting.

H = High multi-path sensitivity gives low stereo reception and switches to mono to keep interference to a minimum. Recommended in hilly areas.


Anyway, back to the SC-816. This stereo has four SRC modes, not three. And, most significantly, the SC-816 controls this function via undocumented modes of the front panel buttons. This led me to believe that there might be other functions tucked away in this stereo. In yet another example of how I have much too much time on my hands, I tested each and every one of the SC-816's buttons while powering the unit on. Here's what I found:

Pressing and holding preset 1 while powering the stereo on will start the volume at a moderately loud level. My best guess about this feature is that it approximates a 90 db listening level. The speakers in the 70 series cars are all rated 90 db at 1 watt, so maybe this preset 1 function is for setting the volume to some reference level for testing purposes.

Pressing and holding preset 4 while powering on will display a code on the LCD panel. This code does not correlate to any serial number, model number or any identification printed anywhere on my stereo, nor does it correlate to the four digit security code for my particular stereo. On my stereo, the code that is displayed is "07156." If yours is different, or even if it's the same, I'd like to hear from you. Maybe there's some correlation between models and years, so let me know what you're driving if you write me. (This just in: one reader with the SC-815 stereo has a code of 06155. Another reader with the SC-816 in his '98 S70 tells me that his code was the same 07156 as mine.) My best guess is that this is the zip code for where Jimmy Hoffa is burried. Zip codes matching the pattern 071xx are in the Newark/Irvington area of the meadowlands in NJ. The US Postal Service web site doesn't list 07156 as a valid zip code, but you know they wouldn't publish Jimmy Hoffa's zip code anyway. At least Jimmy can get his mail. The big question is "how do the swedes know?" Hmmm.... :)

Pressing and holding preset number 5 when you turn the stereo on will cause the display to show "USA" or "AUS" for the Australian market. When the display is in this mode, pressing that same preset a second time will switch to the other mode. As far as I could determine, this merely switches the FM station separation from the US standard of 0.2 Mhz spacing to the rest of the world's 0.1 MHz spacing. BTW, this frequency mode switching is described in the regular S70 owners manual.

Some new functions appear after the stereo has been disconnected from the battery:

Pressing and holding preset number 3 when you turn the stereo on will activate all LCDs on the display. Pressing 3 again will toggle between that state and another display, possibly in Japanese. (These stereos are made by Mitsubishi for Volvo.)

Pressing and holding preset number 6 when you turn the stereo on will allow the stereo to function for about 3 minutes, after which time the stereo shuts off and resumes the security lockout function.

Pressing and holding the "auto" button when you turn on the stereo will allow you to erase all station presets. When "erase" is displayed on the LCD panel, pressing "auto" again will confirm the erase command.

All of the other presets and other buttons seem to have no additional functionality on the SC-816. The equalizer settings on the SC-901 are accessed by holding down preset 2 if I recall correctly, but again, this seems to do nothing on the SC-816. But someone must know how to change the allegedly built in equalizer on this stereo. The truth is out there... somewhere.

If anyone can reference any official Volvo documentation on the functions of the "double secret stereo programming buttons," I'd love to hear from you. I'm also trying to find trends in the factory SRC settings for each model of car that the SC-816 is installed in. If you can add anything on this subject, please write me. If you give me good information, then I'll tell you which dashboard switch has a secret start up function to enable 18 lbs of boost on the T5 cars. ;) (click here for details)


Back to Volvo