Hmm.... built-in subwoofers. There's a can of worms.
Just as the portable transistor radio never sounded as rich in tone as the bigger speakers of a home stereo,
View attachment 309193
then it should stand to reason that a sound bar which might only be a couple of inches tall and maybe 3" deep is going to be limited on the size of the bass speaker drivers it can accommodate.
View attachment 309197
Typically, they are 2", 2.5" or 3" in diameter.
View attachment 309201
View attachment 309212
Contrast that with a sound bar with a separate subwoofer,
View attachment 309194
housing 5.5"~6" bass driver
View attachment 309196
and it shouldn't be too difficult to guess which will produce a richer tone.
Naturally though not everyone can find space for the sub, and that's fine so long as the expectations are adjusted accordingly.
There are some tricks that are commonly used to help bolster the bass output from smaller drivers. Bass porting is now pretty-much universally employed. It can't make the sound significantly deeper than the driver size can manage on its own. But it can add a little more power to the sound and at a frequency just below where the bass from these small drivers would normally tail off.
With all this in mind, then I'd recommend the Yamaha SR-C20A. It's at £169 from the RicherSound site.
Key points in relation to your 'wanted' list
"
No separate subwoofer" - that's fine. The SR-C20A has no separate subwoofer
"
Not wider than 90cm" - that's fine. The SR-C20A is 60cm wide
"
Has an optical input" - that's fine. The SR-C20A actually has two optical inputs.
"
Has a HDMI input with ARC" - that's fine. The SR-C20A has a HDMI ARC input - and before you ask,
yes, it's compatible with the TV's HDMI ARC socket. All HDMI ARC connections are compatible with each other.
You require no more clarification on this point. This is the belt and braces answer.
View attachment 309214
"
Makes dialogue easier to hear" - that's fine. The SR-C20A has a feature called
Clear Voice. This helps with dialogue.
"
Has a remote learning feature" - No, it doesn't. But you don't need that when running an ARC connection. The TV takes control of the sound bar for power On/Off,
and for volume control including mute. Learning was only required when the connection to the TV was by optical. There is no reason for you to reject the SR-C20A.
The deal sweetener is that Amazon has the Yamaha SR-C20A at a special price of £119.95. The sale page linked
HERE calls it the C20A in the page headline. Read down to the specs though and you'll see the full model name is given: SR-C20A. This is the same model as the RicherSound site, it's just at a much cheaper price.
Whether you buy from Amazon at £119, or Richers at £169, or you manage to find a retailer charging the full list price of £229, you will still need to buy a HDMI lead. This Amazon Basics HDMI lead that supports HDMI ARC will do you just fine.
LINK Buy it at the same time you order the sound bar.
That's it. Job done. All you need do now is place a couple of orders.