This is my reply to your question.
http://edsaudiopages.blogspot.com/2021/06/subwoofer-and-satellites.html
So, based on my 30s speedread, it sounds like you think my plan to cross to mono active bass ~150Hz will work?
It still matters where in the room you place the single woofer, even more than with two woofers.
It will work, you just won't have a stereo signal below 150Hz, which does little for "stereo perception".
I take that to mean either...
1. Keeping the system in stereo below 150Hz doesn't do much for spatial enhancement so mono bass is fine.
Or
2. Not having stereo below 150Hz hurts spatial perception.
Which do you mean?
------------
In researching this, I came across many articles and posts by recording guys who encourage mono-ing below 100~200 Hz to ensure that there's adequate bass (in phase) when their music is played in mono. These appear to refer generally to pop music, not classical. Mono or L+R playback happens with the vast majority of smart speakers (Google, Amazon etc), in lots of cars, boom boxes, etc. And the vast majority of vinyl records have mono bass to ensure trackability. So there are many reasons to believe mono bass in a stereo system doesn't hurt the overall sound.
In addition to what has already been wisely said by everyone, I would like to add that the "stereo effect" is not perceived by all listeners in the same way and with the same intensity.
However, as far as I know, the "stereo effect" is also related to the differences existing in the signal of the two channels.
The differences (if any) existing in the signal of the two channels are more involved in the creation of the "stereo effect" at higher frequencies since the higher the frequencies, the more directional they are, the lower they are, the less directional they are. IMHO
So, personally I wouldn't worry too much about splitting hairs over the few hertz difference at low frequencies.
However, as far as I know, the "stereo effect" is also related to the differences existing in the signal of the two channels.
The differences (if any) existing in the signal of the two channels are more involved in the creation of the "stereo effect" at higher frequencies since the higher the frequencies, the more directional they are, the lower they are, the less directional they are. IMHO
So, personally I wouldn't worry too much about splitting hairs over the few hertz difference at low frequencies.
1) Yes, for the most part.
2) Having stereo presentation of signals below 150Hz can further enhance spatial perception, but for most music makes little difference in acoustically small rooms.
That said, there are many (arguably most) recordings to tape, vinyl, or digital with stereo content below 150Hz, the choice of how that information is presented is yours.
My studio system uses a pair of mono summed subwoofers below ~70Hz, my home theater mono summed bass below around 150Hz, with mains overlapping their response.
Art
There are advantages and disadvantages in both mono sub-bass (one or more/multisub subwoofers) and stereo sub-bass (usually a pair or stacked pairs, placed near the main speakers). My experience (disclaimer: only one data point and anekdotical, but enough years of dragging subs around a room, to be confident enough to share that experience, ymmv) is that using one subwoofer, that it might be better to choose a lower crossover point to avoid localization. Doing so, you have the benefit of finding the best place in the room for that one subwoofer and still have your stereo image intact. You can crossover higher, but then it seems to be better to place the subwoofer between the speakers.
The same for mono sub-bass distributed over multiple (distributed) subwoofers. In this case, you can even out the bass response in the room even better without harming the stereo image. A higher crossover point is not recommended due to localization.
In the case of stereo subwoofers, if they are placed near the main speakers as you might expect, a higher crossover point could be possible. In that case, the phase difference with the main speakers should preferably be small, when they have a relatively large overlap in the crossover region. Downside to this placement is that you can't even out the bass response as well as with a mono distributed multi-sub approach. Therefore it is more room dependent, a large room is more forgiving and stereo bass perfectly fine, and in small rooms the mono (multi)sub approach may be better.
The source cited says nothing about the 80Hz limit claimed in the Wikipedia article. In free space, humans can localize with reasonable accuracy significantly below 80Hz. Some directional sensation likely exists down to the lowest audible frequencies. In rooms, things get more complicated due to modal behavior, but David Griesinger (Lexicon), Thomas Lund (Genelec), and James Johnston (Bell Labs, Microsoft, DTS/Neural, etc.) all claim that directional/spatial sensation is intact down to 40-50Hz in a properly set up room and that having two or more independent channels in this range is important for envelopment. There are a number of sources linked here.
Thank you for the link. That is good reference material if somewhat confusing on the first pass.
It seems likely that most recorded pop music does not contain much stereo information in the bass, for reasons already covered. Classical, "audiophile", and some jazz recordings seem likely to contain more stereo bass simply because there's more to be gained by doing so in the music of those genres: more purely acoustical instruments played in real spaces with better capture of spatial data.
My practical concerns are --
1. Reducing potential overload (and distortion) of the 6" Satori mid in the all important <200Hz region -- the bass range of the piano. To achieve this, I expect the XO needs to be no lower than 150 Hz.
2. Not limiting the speakers' spatial qualities by crossing at too high a frequency to mono bass.
The only reason I am considering mono bass is the presence of the sub feature in the Wiim devices, which I consider excellent high performance/value, and the fact that this system is not for me. The end users are not as attentive as I am to recorded music played in their home, and they rarely listen to classical. The speakers are likely to be used with TV program material at least half the time.
I expect that empirical testing is the only way I'll be able to determine whether mono bass is acceptable for this system.
Last edited:
