I use the larger Sonos Sub with the Arc and at default settings I notice a difference. Although I’m currently using the setup with Trueplay disabled.

I do have the Sub-Mini too and use that with a Beam (gen1) + surrounds in our main bedroom and notice the difference in Bass frequency immediately and adjusting the Sub-Mini volume up makes the Bass far too much for my ears so I’ve just left it at default.

Maybe you need the larger SUB (or two) for your room - my Arc Room is 22’ x 14’ and the main bedroom is around 14’ square. In my use-case I’m really happy with the Sub output In both rooms. 

My thoughts are to perhaps try you Sub Mini in different locations in the room and perhaps try it with Trueplay enabled/disabled. My own preference is to have a Sub out in front of my listening position on the floor in a corner of a room (generally speaking).

Thank you, I'll try different spots in the living room tonight, but what leaves me confused is that apart from the increase in bass output I was expecting to notice an improvement in the mids reproduced by the arc (that’s what all the reviews are saying), by freeing it from outputting lower end notes, but it seems identical to me

Same here

i paired the sub mini with a beam gen 2 and two play five has surround 

if I set sub mini to 0 level, I can’t even see the sub mini working.

at first I was even believing that my unit was broke (cause 0 is default level). 
 

i can see the sub mini working (just a bit) if I put it at +5 minimum.

i think it does not supposed to work like this and the « 0 level » should be adapted to existing equipment. 

Maybe try Trueplay tuning the room (again) and see if there is a difference with that feature enabled/disabled. Also try a different audio source, perhaps.

You mentioned you have tried +5 Sub volume, but you can go higher than that and/or adjust the Bass slider control in the EQ settings, to perhaps achieve an outcome of how you like to hear the playing audio.

The default setup settings may not suit every environment, or everyone.

I’ll try a new trueplay

i know I can push the sliders to get more bass, but I think at a default setting the sub should do something, not like if he is dead…

Obviously I can’t hear/see what you’re experiencing, but maybe it’s the audio source you are using? If it’s TV audio, then ensure the ‘now playing’ screen in the Sonos App shows the audio as DD 5.1 or Atmos, rather than PCM 2.0 stereo, just as an example.

Subwoofers will be more efficient when placed in the corner of a room, near the walls.

Indeed, placement is key for a subwoofer. The frequencies are substantially more apt to be altered by placement in the space. And there’s only so much that can be done by TruePlay. 

It is fortunate, in many cases, that subwoofers frequencies are often perceived to be omnidirectional, and they don’t have to be placed in the same “plane” as the other speakers. 

The Sub Mini goes very deep so the placement in the room is very important. Sometimes, moving it a few inches will completely change the sound. Trueplay is supposed to help improve this, but sometimes you’ve got to move the Sub elsewhere to find the best sound.

UPDATE: Changed location of the sub mini and it made a night and day difference: now it really rocks!!

Better when putting sub in the corner near walls and after a true play 

But still thinking that it’s not correct to have to put it at +4 at least for the mini to do something with my play five duo.

what’s the purpose of the range -15 to 0 in that case ?

Different listening environments and we each may hear things differently, that’s the reason the customisation controls are there in the Sonos App. I prefer my Sub-Mini at its default Bass setting, my Wife would prefer less, but my Son would likely want its volume increased to a much higher value. 

I get that : 
Everyone have different tastes, and the settings in the app (equalizer, bass setting, loudness, etc…) are here to answer each one of us with our preferences. 
 

what I’m saying, (but my English might be not really good as a French guy to be understood), is that with my setup, between -15 and +0 on the sub mini there is 0 difference. Nada. 0
Between that range the sub doesn’t even tremble.
That’s not a matter of taste, he act Like there isn’t a power cord on the unit.

same for music, film, etc…

it might come, but I think Sonos have to « calibrate » the bass response of the mini in a more adaptive way regarding the setup of the owner.

@xenadondoit,

In my case the ‘Sub level’ adjusts the volume output of the Sub - I personally notice a very ‘clear’ difference between the two extremes -15 and +15 values

I can ‘hear’, & ‘feel’ the difference and ‘see’ the difference too, if I look at the movement of the two opposing speakers within the Sub, when the same Bass audio is played at those two mentioned settings.

Maybe try various audio sources, but if the issue persists for you, then perhaps there is an issue. If you do think that might be the case, after trying various audio sources, then I would go onto submit a Diagnostic Report and discuss the issue with Sonos Support Staff via this LINK. Maybe video what you see/hear too, to assist with the support request, if you think that may possibly help.

@xenadondoit, 
As a further afterthought, when you were testing the Mini-Sub level settings of -15 and +15 were you ‘perhaps’ playing TV PCM 2.0 audio? (I do appreciate that you mentioned music playback too).  If so then maybe try it again whilst playing Dolby Digital 5.1 audio instead as that has the .LFE channel audio output, which you should clearly notice the difference between, using those two sub level settings. That’s if your Sub-Mini is of course part of a Sonos HT setup.

Just in case you are not aware, the type of audio output will be shown on the ‘Now Playing’ screen in the App when playing TV audio.

Anyhow I hope that assists too.

SONOS cannot renegotiate the laws of physics.

You can investigate these laws. Use a music track with an active, thumping bass (typically any classic rock-n-roll track will suffice), and a pack of Post-it notes. Play the track while walking close to the walls. When you notice a spot with increased bass, mark the wall with a Post-it and continue around the room. You’ll usually notice four spots (why ‘four’?) with much more bass. Mark this Post-it with “!!”. Now, step back and you’ll notice that the Post-it’s are more or less regularly spaced around the room. The Post-it’s are located at “peaks”. Midway between the Post-it’s is a “null”. Positioning a subwoofer or listener at a peak increases bass efficiency, while subwoofer efficiency is decreased at the nulls. After some practice you’ll be able to identify some less significant peaks and nulls throughout the 3D space.

If you accidentally locate the subwoofer and yourself at a significant null, the subwoofer will not have much effect -- regardless of it’s power or calibration.

In my college apartment I found a huge peak and placed a chair at that peak. Bass seemed to explode from inside your body. Males loved this seat. If I moved the chair a few inches the peak was gone. The smarter, more observant males would move the chair back to the peak.