DeudeMann
Active member
So I am a very recent purchaser of a low-mileage 2015 SL and am quite pleased with the car overall. As a daily driver it was what I was looking for.
However, going in, I knew it would be practically impossible to install an aftermarket system, especially the head unit. Since this car came with the Bose system, I looked into what I could do to improve it. One thing for certain is the Bose subwoofer is not adequate, at least not for me. It sounds OK, and being an offset Transmission Line (TL) produces a lot of 'bass' for using such a small driver, as is the nature of well-designed TLs; I have built some TLs for the house.
Thanks to this forum I found out that the Bose subwoofer is a passive unit, or in other words the box in the hatch just has a speaker and no amplifier. This meant that it would be possible to use the signal sent to the Bose subwoofer as a high-level input into an aftermarket amplifier which in turn could power my own subwoofer system. I've built several subwoofer enclosures so all it would take is effort. Time to get busy.
First, I knew that this would be an SQ (sound quality) build and not a SP (sound pressure) build, meaning I was optimizing for modest amounts of good sounding bass and not huge levels of lower quality bass. In a vehicle, this usually means a sealed system, which means tight and clean bass response at the cost of efficiency. Even though a sealed system has significant roll-off at lower frequencies, this is compensated, at least in part, by the cabin gain of the vehicle. Since a vehicle interior is essentially a small, mostly sealed volume, the response of the vehicle volume helps augment the lower frequencies lost by the sealed enclosure's response rolloff.
After much investigation into my options on drivers, including some 12" subwoofers I already owned, and some modeling in WinISP I opted for two 8" drivers, namely two Lanzar MaxP84, which are surprisingly good for their cost (about $25-$30 each). For the amplifier I chose a Power Akoustic RZ1-2300D, which is a monoblock (single channel) Class D amp, which means it is small, and efficient, both of which are good for this application.
Next, onto the cabinet design...
However, going in, I knew it would be practically impossible to install an aftermarket system, especially the head unit. Since this car came with the Bose system, I looked into what I could do to improve it. One thing for certain is the Bose subwoofer is not adequate, at least not for me. It sounds OK, and being an offset Transmission Line (TL) produces a lot of 'bass' for using such a small driver, as is the nature of well-designed TLs; I have built some TLs for the house.
Thanks to this forum I found out that the Bose subwoofer is a passive unit, or in other words the box in the hatch just has a speaker and no amplifier. This meant that it would be possible to use the signal sent to the Bose subwoofer as a high-level input into an aftermarket amplifier which in turn could power my own subwoofer system. I've built several subwoofer enclosures so all it would take is effort. Time to get busy.
First, I knew that this would be an SQ (sound quality) build and not a SP (sound pressure) build, meaning I was optimizing for modest amounts of good sounding bass and not huge levels of lower quality bass. In a vehicle, this usually means a sealed system, which means tight and clean bass response at the cost of efficiency. Even though a sealed system has significant roll-off at lower frequencies, this is compensated, at least in part, by the cabin gain of the vehicle. Since a vehicle interior is essentially a small, mostly sealed volume, the response of the vehicle volume helps augment the lower frequencies lost by the sealed enclosure's response rolloff.
After much investigation into my options on drivers, including some 12" subwoofers I already owned, and some modeling in WinISP I opted for two 8" drivers, namely two Lanzar MaxP84, which are surprisingly good for their cost (about $25-$30 each). For the amplifier I chose a Power Akoustic RZ1-2300D, which is a monoblock (single channel) Class D amp, which means it is small, and efficient, both of which are good for this application.
Next, onto the cabinet design...