ive not done anything wrong just asking questions
Hey mate, better to ask question if you are not sure, I like people asking questions, as it provides an impression on how everyone thinks! :graduate:
Now, the amp you have does not have subsonic filter so if you are using a sealed box, it maybe be tuned at 35hz (as a good overall sound frequency starting point) so the subsonic filter can be used but will not have any issue with the subwoofer.
The subsonic filter is a good prevention to your subwoofer, think of it as an insurance for your subwoofer and it outshines when you are using a ported box. Usually they expand from 20hz - 50hz depending on the type of amp, and are set at 25hz as a good measure. In reality, you cannot get bass lower then 30hz in your car, as the environment will not allow it, but I am sure you have heard people making custom box and tuned it low , say 28hz, but that does not mean, you will get 120db of bass at 30Hz, :uhoh: as most vehicles peak around 50 -60Hz
The bass boost function is usually centered around 45 Hz that provides a "peak" in that frequency and is used to compensate for your subwoofer enclosure, or placement / efficiency issue., But if you have high sensitivity subwoofers, then using the feature will just 'drown' the midrange/ mid- bass/ and high frequencies and is useful if you are into SPL :nerd:
Keep your eye out for a class D monobloc that you can buy later as its a good feature to have if you have a ported box. Not having them can reduce the life of your subwoofer in the ported box if you like to 'pound the pavement' but if you listen to it at low to moderate listening levels then its ok, but keep your eyes peeled for one you can get in future.
Hope this gives you some a better understanding of the amps bass boost feature mate! :veryhapp: