1. Which car are we talking about here? Some car audio purists might scoff at it but car manufacturers actually pay attention to your stock car audio system. Whether you may be able to use your head unit's volume knob to control your volume will depend on whether your system is interfacing via an analog or digital signal.

If you have your everyday typical car which uses speaker-level outputs (which are analog) then the answer is yes. 90% of the cars out there have this answer. But let's say you're well-off and you have a nicer car with an external amplifier - in this case the system might be interfacing via digital which will move your volume control from the head unit (where it processes data) to the processor.

A very good example of this is my car which I have retained my OEM factory head unit but I'm interacting with my processor via digital out.


2. I do not have the answer for #2. Unfortunately, installation isn't my forte.


3. No. For a 2-way system, sail-mounted tweeters is actually an excellent location. Midbass location depends on the car but most enthusiasts aren't that hardcore to chop at their doors just for the sake of attaining "better". You will not be compromising.

Tip: Depending on the stock midbass location, it might be a good idea to modify them in order to "free" the speaker. This reduces resonance of sound waves bouncing off the stock speaker grills which are often restrictive so that people can't see them.


4. What do you mean "target matching"? If this means having the same set of speakers, it need not be. It need not even be same-brand speakers. As to what speakers to go for, I will suggest settling for a price that you're comfortable with. For example, if I were to build a 200,000php system build, I might allocate 20,000php for rear speakers but I doubt I'll budget more since it isn't my priority.

Truthfully, on a properly set-up'ed system, just the front speakers is enough. Listen to my car and I'm pretty sure I am not compromising the backseat passengers. They still have great tonality at a good enough volume (in fact, they'll probably be deaf if they complain about the volume) but they won't get imaging and staging.

Most people who are.. let's say more serious into this hobby simple defeat the rear speakers. Why? The art of getting a great SQ inside the car is controlling the car environment - you control how these sound waves interact with one another. Controlling 4 drivers (2-way) or 6 individual drivers (3-way) is hard enough. If you throw in rear speakers, it simply shoots up the difficulty a lot more.

In the Philippines, I haven't heard a stereo system with a properly implemented rear-fill. The type of rear-fill that adds to the ambiance or to your test sheet scores and not wreck the entire sound presentation. It says a lot about how hard it is in tuning one. If you plan on this route, going 5.1 might be a better idea.


5. Un-tuned? Then the passives flat out win. What an "active" system simply means is that you take advantage of your DSP's capabilities and tune each driver to perform optimally. When you talk about potential, active takes the crown. When we compete, most of us are in one form or the other using an active configuration. Whether that be a 2-way/3-way fully active or a 3-way semi-active configuration.


6. Correct. Class D designs are more efficient in converting power and because of this efficiency they also do not emit a lot of excess power in the form of heat. This allows amplifier designers to lessen the amount of heat sinks needed to cool it. Originally used for subwoofer duties, full-range Class D amplifiers are quite common nowadays as the technology evolved from 2010 onwards. And because it's still not yet mature, I will recommend you stick to known brands. For example, the Alpine PDX series of amplifiers are great but my personal favorites are JL HD series of amplifiers which sit on top of the Class D designs right now (the HD900/5 namely - just two of them are enough to run any system).


7. It's hard to quantify "moderately sensitive speakers" . Let's just say 50W of power is enough. Since power is cheap nowadays, I usually recommend eyeing for 75W. If you can go for 100W, why not? Amplifier power is inefficient because it scales exponentially. If it's volume efficiency you're looking for, I will suggest you start searching for efficient drivers.

On a personal level, I typically use around 400W in powering my entire system at a loud volume level. And trust me that I listen loudly. I use to joke that I'm not even tapping 20% of my available power (it can't anyway since my alternator won't keep up with the required amperes).


8. Nope. Subwoofers won't make a difference whether it's in mono or stereo. There's no such thing as a left or right signal in subwoofers is because "stereo" or "mono" is only relevant in imaging -- on how to pinpoint the sounds. However for sub-bass of less than 100hz, the sound wavelengths are too long that it doesn't matter. This is why you can have a subwoofer at the bottom of your computer desk and you still hear it getting along with your front desk speakers.

For subwoofers, the bigger - the better. If you can fit a 10" there, do it. If you can't, then go for multiples (ex. two 8" slightly outperforms a single 10")