My speakers all work, but the subwoofer sound lowers when they are all working

I have a Sansui Subwoofer and when i turn it on the sound coming out is very low, its very hard to hear, can anyone advice ??

Hi, pls don't get me wrong, but might it be that you are just hearing more of either the front or the rear since they operate on the frequencies our ears are attuned to with the sub just producing the low ones. Other than that, might it be also the placement of the speakers? The front and/or rear are placed relatively higher than that of a sub woofer hence closer to the level of your ears and therefore you can hear them more distinctly while the sub being lower, you probably feel it as well as hear it but not as loud. Since all of them are working albeit the sound level, I can think of no other explanation. If however this is not the case before and that this problem just recently came up, then may I suggest that you bring the set to a qualified service personnel since this involve checking out the individual amplifiers and their attendant electronic circuitry. If you are comfortable working down to component level, you would probably have to start with determining how many amps are inside the unit and diagnosing each one including the PSU. Far chance as it may be, there is a possibility that the PSU is not able to supply the current demands when all the amps/speakers are working. Hope this be of some help. Pls post again how things turn up. Regards.