In very broad terms soundbars come in two flavours. The first is what you've got already which is essentially just a pair of stereo speakers arranged in a slim bar format and either with or without a sub. The audio processing, such as it is, is very minimal. This is why sometimes you're finding that voices are swamped by music and effects. A good stereo amp with Hi-Fi quality speakers will sound better in general but won't have the control option to help rebalance the sound. It is the same situation with better (more expensive) sound bars until you hit the point where thay have proper surround processing. [see below]
The second flavour of sound bar is that which is part AV receiver combined with speakers that try to bounce sound off walls to create the illusion of rear speakers. The best known and most effective brand for this is Yamaha. Their 'YSP' range have been doing this sort of thing for more than 10 years. So, on the one hand you have the advantages of the sort of set up flexibility and input range of an AV receiver plus some toys like wireless music streaming on the higher-end models; on the other is the higher cost for the convenience of the technical solution to getting rid of wires. Have a look at
YSP3300 (roughly £500) for an idea of what these sort of things can do.
If you're looking for something that is going to act as a hub device for any sources you're likely to connect, and you want to solve this sound balance issue, then you need to look at either something like the £500 Yam YSP3300 or an AV receiver and some combination of speakers to match your needs. The TV is a poor hub device because it limits the audio format via a headphone socket/optical out/HDMI ARC connection to just plain stereo for any direct input source via HDMI or an AV connection. The exception to this is 5.1 digital audio from the TV's internal
HD tuner* or 5.1 digital audio from streamed sources with a smart TV but only if the audio stream has the encoding.
AV Receivers range in price from £150 to in excess of £2000. Something at the entry-level with the connectivity you would need and wireless/BT streaming feature would be the Denon AVRX520BT @ approx £220-£270. This can then be combined with any combination of speakers from a basic stereo pair (2.0) right the way up to a 5.1 set and anything in between. You could quite easily have a centre and stereo speakers (3.0), or stereo plus sub (2.1) or three front and sub (3.1). The receiver will process the sound according to the speaker combination in use.
Even with a stereo speaker set the processing on the amp/receiver allows for the balance to be changed between dialogue (centre channel) and music/effects which is normally steered to the L&R and surround speakers.
Others here can go through the in's and outs of the various AV receivers and speaker packages available in the market. All I'll say at this stage is that building up a system over time through buying a stereo pair then adding centre and sub later will be more expensive but give better audio quality. It is possible to buy entry level complete 5.1 speaker packages from £130 and then elect not to use the two rear channel speakers. This will then leave you with a 3.1 system in the living room, and that arrangement will be superior to the Philips sound bar, but the quality of those speakers won't match that of the build and performance of stereo speakers costing £100.
I hope this helps.
* non-HD TV tuners aren't capable of giving digital 5.1 audio out. Also, true 5.1 digital audio is broadcast on only a very small number of HD TV channels. Most of the time it is plain stereo.
