It would be illogical to suppose that it’s anything other than a scale with 20 steps. 

In actual fact moving the slider to the right would reduce the left channel output. Does it matter whether it’s exactly 2dB or not? Simply adjust till it sounds right at the listening position.

Yes it totally makes sense when you are trying to realize why you’re having an imbalance. Adjusting the balance is not the optimal way to solve these problems. It's just a quick fix, but adjusting placement of speakers, or dealing with reflections is the better way. Plus, I’m trying to understand if my ears are playing any role in this imbalance. If I do +5R (I know it means reducing left, but in the app it’s +5R) and I know it’s 5dB then that’s a HUGE alteration. But if +5R means 0.5dB then that’s a whole other story.

It’s most likely to be 5% per step. Clearly when at +20R the left channel is not 20dB down, as it’s totally silent. 

You're probably right. 20 does silence the other speaker entirely. I just can't stand Sonos hiding so many technical details from their devices. It's like Sonos is barely an audio company. True audio companies are transparent about their technology. Everything is secret. Sub crossovers.. Exact operation of loudness.. Power consumption. It's ridiculous. 

Sonos is indeed an audio company. It makes kit that works well together and sounds really rather good.

What it isn’t is an audiophile company, where apparently the operation of the equipment is everything and the music is distinctly secondary.

You couldn't be more wrong. I thank you for responding to my inquiry and I guess I can just rely on your 5% idea which makes sense.

All speaker companies that respect their own name detail all specs of their "Audiophile" equipment as well as budget equipment costing way less than half of a Beam. I went all the way from Beam to Arc with a Sub in both (and without). Sonos value for money audio quality is the worst I've seen. The Arc is not even close to being a $799 speaker. Or a set of left right center speakers. The sound from even the most basic bookshelves is far superior. My SVS sub costs less than a Sonos Sub and is so much better.

Sonos focuses on its name, brand, marketing more than creating good sounding equipment. People buy it because of comfort and asthetics thinking they're getting premium sound. In fact the JBL and Samsung bars sound better at the same price. They might not have athmos but the sound is superior.

I actually love the Amp. If is really a very convenient good sounding amplifier, but the rest is overpriced for no good reason.

Even the "cheapest" low tech audio companies are transparent.

Sonos is audio for the masses. And the masses don't care about specs. So Sonos doesn't care either. 

I can’t think why you’re talking of sound bars if the requirement is for the best music experience. Of course discrete L and R speakers will present a better sound stage. 

Try a pair of Fives with (or even without) a Sub, ideally with Trueplay room correction. 

I’ll add my two cents….

@yuvalfrr..I don’t know how old you are but back in mid 1960’s a company was formed called Bose (maybe you’ve heard of it). Back then Bose marketed a speaker called the Bose 901 as its Flagship speaker set. Needless to say you either liked the 901 series or you didn’t. Audiophiles were also divided with their opinions. Guess what...the division was for mainly the same reason you are citing now….no printed specs.

IMO unless you are an engineer what difference do specs make if the sound is pleasing to your ear. When I first started my serious listening there were only few ways to adjust your listening experience by analogue adjustment of Bass, Treble, L/R Balance and eventually Mid-Range on some more expensive amps. Today the consumer has access to full range EQ..assuming they know how to properly make the adjustments...most don’t.  Have you ever heard of Sonos TruePlay? But that’s a subject for another time.

Back-in the day before the brick n’ mortar big box discount stores you went to a local dealership that carried varies brands of speakers with listening rooms. The rooms might be divided by price range (i.e. high/mid/low).  I’d pick out 3 or 4 brands in my price range and audition them against a more expensive speaker that I couldn’t afford...that’s because of it’s price the speaker was suppose to sound better than the one’s I picked. Yeah right….anyway...

I’d be escorted to a listening room with all speakers setup in pairs and I’d listen to the expensive speakers first then one of the ones I’d chosen. I might add that my back was turned to the sound stage so my decision was made solely on acoustics to my ears. Granted it was a controlled environment and which ever speaker set I chose was not going to sound the same in my home. But that was the best measurement I could use as a gauge to invest my hard earned dollars.  Bottom-line reading the specs served only to justify a price...maybe...but in the end it was my ears that mattered.

Oh...back to that company called Bose. To this day Bose doesn’t publish specs. Yet they sell a Bose Life Style 650 Home Entertainment System at $3,999.00 (USD).  I’m not a big fan of Bose as I prefer Sonos. However, $4K for a system that doesn’t support Dolby Atmos versus $1,856.00 (USD) for a Dolby Atmos Sonos home theater system...well...you do the math.

The audiophiles that I encounter are adverse to specs. They believe that their superior hearing ability will guide them to the “best” sound and that specs are poor predictors because the audiophile believes that science has a defective understanding of how we hear and therefore there cannot be any valid metrics.

With respect to 0.5dB level differences, this is below the threshold of untrained listeners ability to detect. By “untrained” I mean individuals who don’t regularly work in a studio environment. However, in A/B instant comparisons, even though the listeners will probably not be overtly aware of any level difference, since we tend to prefer the louder presentation, 0.5dB becomes very significant. On a practical basis out in a room 0.5dB is surprisingly difficult to measure unless we are dealing with single frequencies. This is because rooms and speakers do not have uniform response with respect to frequency. The measurement device would need to concentrate on the frequency that was most important to the listener and this is unknown.

I’m familiar with a, now defunct, audio store that would use level differences to sell the “right” speaker. The sales people were shown that very small level differences would sway the comparison and demos were stacked such that the speaker that the sales person wanted to sell, for whatever reason, would be slightly louder. What would be the “reason”? In some cases the sales person felt that ‘A’ was a better product and guiding the customer to ‘A’ was in the customer’s best interest. And, of course, there could be special advantages for the sales person when selling product ‘A’.

In general there must be a 10dB difference before the listener claims “twice as loud”.

Instead of the second para quoted, I would say that Sonos isn't a company that caters -panders?:-) - to the needs of audiophiles that are as interested in interacting with the equipment as they are in the music. And in many cases, are more interested in the former.

But Sonos kit is perfectly capable of delivering audiophile sound. This by the way is a subjective opinion, having spent ten years in the world of the audiophile hobby, that no one can argue with because, in the first place, there is no accepted definition of the term “audiophile sound”! I would therefore put forth that Sonos makes kit that can deliver audiophile sound to the masses, but to an audiophile this will never be an accepted definition as well, because it is a contradiction in terms to the elitist hobbyist, that is typical of many of the audiophile set. Been there, outgrown that.

To the OP:

What do you find missing in the amp spec, that comes in the way of comparing it with other amps for making a buying decision?

As for being overpriced, I agree, but not for the reasons you mention. I can get the same sound quality as Sonos from an Echo Dot wired in to the analog inputs of quality active speakers for a lower price. Especially if a suitable pair of studio monitors is picked. But Sonos is not overpriced if you are comparing something like a Sonos One pair + Sub or a Five pair + Sub with a typical HiFi brand set up for stereo music play with sound quality that is in the same ball park. If you know of any other that is much cheaper that does all that Sonos does, name it.

I don't know anything about Sonos products for TV, but as pointed out by others here, comparing these for music sound quality/price with a stereo HiFi set up is not an apples to apples comparison and is therefore invalid.