Is it possible to add a second Sub?

Hi Proton,

Welcome to the Sonos community

The short answer is No. You can only have one Sub in the 5.1 setup. You can have a second sub with another speak set up and the bring them all together for music.

See how things sound with the Sub set to max output levels!

Hi Proton,

Welcome to the Sonos community

The short answer is No. You can only have one Sub in the 5.1 setup. You can have a second sub with another speak set up and the bring them all together for music.

In other threads from a year or two ago we were discussing the possibility of Sonos offering discrete multichannel HT using a decoder box and multiple Plays/Subs. I like my Playbar HT - especially now that the tuning option has arrived - but the limitations are glaring. I sincerely hope Sonos is working towards a "next-level" HT system.

See how things sound with the Sub set to max output levels!

If you picture your sub output as an EQ curve, the proper technique to adding bass is not to increase the overall level but rather to boost the weakest frequencies. You need more loudspeaker surface area to do this, not more volume. More speaker area will move more air at lower frequencies, thereby boosting the low range. Simply adding volume by cranking up the levels just raises the original curve, which makes the bass boomy and oppressive. It also will quickly introduce distortion as the amp will be driven closer to its peak output and clipping will occur.

It also will quickly introduce distortion as the amp will be driven closer to its peak output and clipping will occur.
That depends on the point at which the amp starts to clip; I have never had reason to boost the Sub levels all the way to the right, but I am reasonably sure that Sonos has designed even these to be below the clipping points of the driving amps. I know that no clipping happens till 75% for sure.
As to the effect of raising output levels in general, what do you think happens to the frequency curve of the sound of my play 1 units when I raise the volume levels from 25% to, say, 50%? Do you think that EQ curve changes with respect to the sound frequencies delivered? Is it not the case that all frequencies are delivered with more energy, leading to higher sound levels of the same EQ relationships? Do I instead need to use two play units to achieve this?
If you use two Subs, both moving air in different parts of the room causing low frequency sound waves to be generated from different parts of the same room, what do you think is the audible effect when these sound waves meet and interference is caused?
Many here have pointed out the limitations of the play bar for HT, but I haven't heard anyone else say that it is the bass delivery of the Sub that is inadequate. Reportedly a new HT solution is around the corner, but don't hold your breath on that including multiple Subs.

As to the effect of raising output levels in general, what do you think happens to the frequency curve of the sound of my play 1 units when I raise the volume levels from 25% to, say, 50%? Do you think that EQ curve changes with respect to the sound frequencies delivered? Is it not the case that all frequencies are delivered with more energy, leading to higher sound levels of the same EQ relationships? Do I instead need to use two play units to achieve this?


A rule in hifi is the farther down the frequency band you move, the more power/more surface area is required to play back the low frequencies - at the same apparent volume level. You lower the volume and the far ends of the frequency response take the biggest hit. This is why many standard receivers for both home and car have included loudness contours, to raise the high and (especially) low frequency response at lower listening levels. Now I have no idea if the Sonos gear - any of it - includes a loudness process in the logic. I think that the lack of readily accessible basic EQ controls (you have to dive deep into the app to mess with any settings) means that there is a contour, but who knows?

So, raising the volume of your Play 1 one hundred percent (from .25 to .5) doesn't cause a linear increase in the frequency curve. It will cause a disproportionate shift in heard frequencies, with the lows and highs benefitting the most - if there is no loudness contour. If there is a contour, you'll hear a more linear increase. Adding a second Play 1, well that will depend on room size, separation and placement of the speakers and playback level. Generally though, adding a second Player set to the same volume of the other Player is going to result in a perceived increase in volume. Remember, you're still adding more cone area which results in more air moving, so... more volume at the same output level.


If you use two Subs, both moving air in different parts of the room causing low frequency sound waves to be generated from different parts of the same room, what do you think is the audible effect when these sound waves meet and interference is caused?

Interference fronts are nowhere near as pronounced for bass as what you'd get for vocal range or higher. Otherwise, what would you do if your subwoofer happened upon its own reflection coming off a wall ten feet away? In fact, many people wall- or corner-load their subs to increase bass response. Plus, practically every home sub I've seen until the Sonos sub has been a down-firing driver. If interference was a concern, having a 180 degree out of phase reflection coming back to the source would be a lot more damaging to HT than having a couple of subs ten feet apart.

Many here have pointed out the limitations of the play bar for HT, but I haven't heard anyone else say that it is the bass delivery of the Sub that is inadequate. Reportedly a new HT solution is around the corner, but don't hold your breath on that including multiple Subs.

I would agree with you there. However, are you sure people are happy with the Subs? Or maybe just so distracted by the Playbar limitations that they completely overlook the Sub? :D

I'm definitely not holding my breath over anything from Sonos. If they decide to stay on their present course of just integrating microphones and Alexa into incrementally improved speakers, I'll be quite happy to hang on to my first generation Sonos equipment until it breaks, at which point I'll be looking at HEOS and whatever other new wireless stuff is on the market. If I can't find anything there, I'll look at discrete components from Denon, Marantz, whomever.

But...

If Sonos DOES come out with a magic box that can decode DD/DTS and allow me to run 7.1/7.2 setup made up of multiple Play 1 or Play 5, plus a couple of Subs, I will buy that.

So, raising the volume of your Play 1 one hundred percent (from .25 to .5) doesn't cause a linear increase in the frequency curve. It will cause a disproportionate shift in heard frequencies, with the lows and highs benefitting the most - if there is no loudness contour. If there is a contour, you'll hear a more linear increase.
I don't agree because I do not find that to be the case with my 1 units, or other amps I use. Increasing the sound levels within a range that excludes the low and high ends of the range, just seem to be loudness changes across the fq board to my ears. A frequency graph on an instrument may show some differences, but since these aren't audible to me, I don't care about these. I have no idea if Sonos does any contouring via DSP.
I agree that at the extremes of the ranges what you are saying takes place to the extent that lows are affected more audibly. At low levels bass loses its presence and needs a boost via the loudness toggle to be well perceived, but an anchored to play unit Sub does the same job better. Nothing as obvious needs be done for the high end.
I don't play music at the other, extreme loud end, but there are reports that the 5 seems to be bass light close to 100% volumes - almost certainly because Sonos does something in the DSP that keeps bass down to levels that don't distort with the available amp power at those levels. I doubt that anything changes at the high end that needs special handling, but again, I never play at those levels.

Generally though, adding a second Player set to the same volume of the other Player is going to result in a perceived increase in volume. Remember, you're still adding more cone area which results in more air moving, so... more volume at the same output level.


I agree but here is the interesting question, via a thought experiment:
Place two 1 units side by side and play them as a grouped zone. And adjacent to this pair, place a single play 1 unit, playing by itself.

Now play the same music through both set ups and using a sound level meter set the volume control of both set ups such that both deliver the same sound levels in the room, at around 50% of the maximum possible levels.

Obviously, the volume levels for each of the paired 1 units will be lower than that for the single play unit.

Are you saying that now with the same sound levels delivered from both set ups, in a blind test one set up will sound different from the other? In what way? How will the EQ curves for the delivered sound differ from each other?