*Gian Paulo
Sorry, I can't see the model of the speaker so it's a hard call.

But unlike siento's observation. I believe that's a passive subwoofer with a fabricated box. Reason for this is the tell-tale speaker terminals from the box as opposed to RCA inputs.

As a general rule, check the cost of the subwoofer driver then just add Php1,000 to Php2,000 for a box. The box cost differs as it will depend on the MDF used by the installer, its cover (either carpet or leather/leatherette), as well as how much internal reinforcements the box has.

In general, the more expensive your subwoofer, the more you want to pay close attention to the box. You throw in internal bracing (some even go for aluminums), the shape of it to reduce standing waves, etc. As an extreme example, home audio JL Fantoms can cost up to Php150,000 a piece for a subwoofer that costs Php30,000.. a built-in amplifier/DSP that's probably around Php20,000 and the rest is box and branding.




*aprilboyidol
Noticeable. Iba na agad yun driver configuration halata na agad

If you're already purchased separate components and are using it. Don't go the coaxial route. If you look at all the modern cars nowadays such as the Mercedes Burmester system to Mazda's BOSE system, all of those uses separate components na.




*AMjohnrae
Your best choice is to first bring it to an installer and check your separates' crossover. It might have decibel attenuation that is decreasing the output of your speakers. In general, it's usually on a 3dB gap (ex. 0dB, -3dB, -6dB). Aside from this, look at your source (head unit)'s settings. There might be settings there that is also reducing the tweeter output.

By experience, most people who have tweeter output problems suffers from either or both of these problems. It's very rare for somebody to be unsatisfied with their tweeter output given factory or aftermarket products.

Also, adding another tweeter may not necessarily solve your problem. Depending on acoustics, it might in fact just aggravate it.