I had a box ibiza (active) of the same power and the same formal (15 "), it really was not pleasant to hear, between parasites (incurable) and the sound too" metal "in all frequencies.
But I could compare with this pack (buy for 90 € TTC) amplified on an amp bridged 1X 400Watts rms. (With a pregnant ibiza broad band active too disgusting)
Construction certe is not superb, one of the screws vibrated and moved speakon outputs (stuck in 10min that followed) + 1 or 2 screws turned into the void, with low, low-volume by heard.
for a sub 90 €, the sound is good!, 400 watts rms advertised are quite wrong of course, rather 250/300rms.
It has a passive filter (hence the ON / OFF to the rear)
Sound and bandwidth in detail:
Announced 20-300 hz (filter ON)
Frequencies from 20 to 25/28HZ not make biensur not hear as you can imagine, it would be too good, finally good normal, false features on this kind of brand are commonplace.
65-100hz frequencies are clean, 50-60hz frequencies are a bit "metallic" but not so bad that ca, ca you can listen nicely, there is a loss of volume for the 35-45Hz frequency (mainly 35 - 40), so I set my equalizer has 6 / 8db a little pressure to lower frequencies and, to my greatest surprise, the yield was very good for the 35-45Hz, the bass was deep and saturation were beginning has a pretty decent volume (he descended fairly well until 32/33 and the yield loss fell dramatically after)
Mounted with an equalizer just for very low frequencies, this box allows you to listen without discomfort or DUB HipHop or low down well.
low ingeneral were not a lot of depth but respectable for this type of product.
I had to go myself one day my broadband pregnant because the RCA cable plugged in for the dead.
so I had more than my box (my main entrance is on the amp), I put off the filter and I sent the music, my 15 "reproduced me all mediums acute low frequencies better than my speakers lanes 3, 15 my "worked channels 3 during 5 days.
the sub BX-1550 A beautiful acquisition and my biggest surprise for my tiny budget of € 90
(Purchased at the base only because we had given the amp m)
If you want sound for cheap nights at all, I recommend a not too bad amp and turn it as you like.
Or try its big brothers in the 18 "has a roughly € 125 TTC, more powerful but no opinion on it