What Audio works in the SL-C?

Some builders scoff at the idea of any audio system in the SL-C- isn't the sound of the engine enough?

And of course, there is some merit to that position- who doesn't like to hear the roar of the engine?  But for those that take the effort to build a quiet SL-C, a decent audio system can make long drives more relaxing.  And of course, real Supercars tend to have high-end audio.  So there's a precedent. :)  Plus, for some builders, audio is just part of the build spec for their car.

So, given a decision to put a system in your SL-C, what works best?  Pretty much any audio system works in the SL-C, from basic radio or iPod-style setups, to full-blown custom setups.  There are, however, a few limitations it's worth keeping in mind when specifying audio in the SL-C.

Physical Limitations

There are several limitations in the SL-C that constrain the set of possible audio solutions. Most of them are space-related.

The most striking limitation is that there is no room in the center stack for a conventional-depth 2-DIN headunit.  Really, there just isn't.  Though the opening in the center stack looks like it would fit such a unit (and does, in terms of width and height), the very limited depth prevents conventional headunits.  You can't easily just cut out useless stuff to make room as is possible in some production cars- the problem is interference with the chassis.  Extending the dash with FG puts the headunit too close to the shifter (it's been tried), and looks ungainly as well.

Recently, Alpine released a shallow-depth 2-DIN receiver that is Apple-focused that some builders think will fit in the opening. It's the Alpine iLX-007. No one has yet mounted it, but measurements seem to indicate a fit.

There is also no good place in the factory dash for a single-DIN radio, either.  Several cars have been built with a single-DIN radio with a flip-up screen mounted on the passenger side, but this implementation reduces knee room for the passenger, is difficult to reach for the driver, and, to some people, looks like a wart.

Finally, there is limited space for normal-sized speakers, either in the car generally, or in the doors.

Possible Solutions

So, what to do?

Several SL-Cs have been built with good audio systems, that perform well and look good as well.  Some approaches that have worked well in the past are discussed below.


At least one SL-C has had a conventional 2-DIN headunit modified by removing the screen and controls, and mounting them in the center stack.  The rest of the headunit is mounted elsewhere, where it isn't visible.  This practice is not uncommon in high-end stereo shops (they call it "meching", because the screen and controls are mechanically separated from the rest of the unit) and is a great solution for those builders who want the features and ease of use of a conventional 2-DIN unit.

A variation of this is a headunit designed to have a detachable front.  Alpine once had a system like this.  This approach is like the meching approach above, except presumably cheaper since it is all factory supported.

At least one SL-C has mounted a single-DIN headunit under the driver side of the dash, recessed so far as to be invisible in normal operation or viewing. You have to bend down and look under the dash to see it, yet it remains accessible by feel.  This is an inexpensive approach that looks great (you can't see it, so there is no indication that there is a radio or headunit there at all) and can work well if you can live with the lack of visual feedback.

Finally, there are companies that make radios designed to be hidden, and operated with a small remote control that can be  stored in the center console when not in use.  For example, http://www.classiccarstereos.com/category/Secretaudio-SST.html?st-t=google-Secret_Audio_Radio&gclid=Cj0KEQjw8-GtBRCMl7m54PzgjNQBEiQAIZckvzhlaKbHhhMMWCxOdB4Hw57zHUaR1ZGPtcE8G2nR9xwaAm_28P8HAQ or http://www.outofsightaudio.com/


Several SL-Cs have had subwoofers mounted in the passenger footwell.  This is a popular place for such a unit, as it is relatively spacious, and because the footwell is so long, the encroachment by the woofer is typically never noticed.

Other popular places for speakers are in the door panels, and in custom-made kick panels.  Because of the way the chassis is built, kick-panel-based speakers don't get the potential damage you might expect.  Speakers in the door panels can be a good idea, especially if the doors can be sealed, but room is limited.  Count on 4-5.25" diameter speakers as a max size.  Here's a case where components are a good idea as well.

A couple of SL-Cs have been built with the speakers in the bulkhead panel behind the driver and passenger heads.  Like door-mounted speakers, there is a natural limit to the depth of speaker mounted this way. and the roll cage and other things may dictate where the speakers can be mounted- so don't cut openings here unless you are certain there is clearance for the speakers you have selected.


In recent years, tablets have become quite inexpensive, while at the same time offering more features that make them a substitute for a headunit.  They are easy to mount in the center stack, take almost no depth, are self-contained, and have a wide range of apps that enable them to do all or almost all the very best headunits can do.

They will typically require an external amp, however, but even good ones nowadays are relatively inexpensive. 

The combination of an inexpensive Android tablet, some well-chosen apps, and a good amplifier and speakers may be all you will ever need.


Of course, you can combine a tablet, a headunit, an amplifier, etc to get the features you want.  For example, one SL-C has a hidden single-DIN headunit, a steering wheel adapter to use the wheel-mounted controls to manipulate the radio, a tablet with audio out to the headunit and an ability to make calls from the tablet, a powerful amplifier, a subwoofer in the passenger footwell, and component speakers in the doors.  

Another high-end car has a powerful amplifier driving separates mounted on the kick panels, with a subwoofer in the passenger footwell.  Instead of a headunit, it has a Bluetooth module, so the owner can play music from an iPod, phone or any other Bluetooth-enabled source.  A discreetly hidden volume control manages sound levels and the entire system is very subtle, yet sounds very good, especially at higher levels (the speakers and amp are pro-hobby level components).

There are countless variations on the theme, and your budget and imagination are the only real limits.