If you are owner of portable speaker Sony SRS-X55 you may already found that regardless of good sound quality it has one major flaw - tremendously huge bass. And this also implies sub-woofer rattling on bass peaks. From my point of view Sony engineers screwed up here really bad.

But there is a good news to, you can fix this. In order to do this, your hands must grow from the right place and you should be familiar with soldering stuff.


Fix is possible because if you have to much bass it much easier to reduce it, than to level up bass if your speaker has none.

Basically you have to reduce amount of current that flow through your bass speaker. You can do it in several ways, by applying one of these attenuator filters:

In my case I’ve decided to use L-pad approach. Calculating correct resistance value was the main challenge here. Main goal it not just add resistance but reduce bass volume in dB on some unknown value. Fortunately I’ve found good L-Pad calculator resource. Advanced equalizer helped me to determine desirable bass level reducing - it is about -6dB or more.


On iFixit site you can learn how to get to the bass speaker and it physical specs: 10W 4Ohm. And here is where problems appears. Because speaker power 10W this means that it literally may consume 10W on spikes, thus I should use 10W resistance. The problem here is that physical size of 10W resistance is big, it is not just big it huge if compared to the free space inside SRS X55. I’m not a real pro in circuits and maybe it is possible to use resistance created for less power like 5W, but I’m not sure about this.


The white thing is resistance itself :(

It is almost impossible to fit 10W L-pad attenuator inside speaker that is why I’ve decided to use single resistance instead. Single resistance specs can be also calculated at L-Pad calculator. So I’ve bought 2 resistances at 9.1Ohm and 4Ohm.


That is how I’ve fit resistance into speaker’s case


9.1 Ohm reduced bass level, rattle disappeared but it is too much. I can not say that there was no bass at all, but height tones became more clear and annoying for me. There was almost no bass rumbling and that is not so good.

4 Ohm just did the right thing. Personally I fell sound in the same way as on original speaker, but bass rumbling does not annoy me anymore, and does not cause my headache to :)

I can suggest that you should use at leas 4 Ohm resistance and maybe you can try 6 Ohm but you should not use values near 8 or 9 Ohm.