04-Aug-2020, 01:37
Delija isn't quite correct.
The subwoofer range may not be mono on 99.9% of recordings because the subwoofer range is variable. It depends on the crossover frequency chosen. Studies have shown that most people are unable to detect the source of sounds below 80 Hz. That means that if you set your crossover frequency at 80 Hz or below, you will probably not be able to detect the source location of the sounds reproduced by the subs but I use two subs in my HT system (a different system to my audio system and located in a different room) and been able to detect the location of one of the subs because the sub was in a corner and strongly loaded a room mode at a frequency below 80 Hz and I was able to detect that that sub was in the corner when the sub was reproducing loud sounds at that modal frequency though I could not detect its location at other times. If you set the crossover at 80 Hz or lower you should rarely be able to notice the difference between 2 subs operating together in mono and 2 subs operating in stereo mode but it may be possible to do so at some times depending on the location of the subs and how each sub loads the room's modal frequencies.
Is it worth using the subs with a stereo connection rather than using them with a mono signal? That's going to depend on where you place the subs and where your listening position is located, plus on the frequency content of the signal going to the subs from moment to moment. Most of the time there should be no significant audible difference, perhaps even all of the time depending on the bass content of the music you're playing and whether or not your room modes coincide with the frequencies of any musical notes. The times when I could tell that one of my subs was located in a corner wasn't with musical notes, it was with sound effects noises like explosions, earthquakes and so on, which were noises with broad band low frequency content that didn't coincide with the frequencies of the notes occurring in the music content of the soundtrack.
I can't say that you will never notice a difference but you may. If you are going to try using 2 subs in stereo mode then the best advice would be to locate them close to the speakers so that the sound from each sub arrives at a very close angle to the sound from their associated speaker. The problem with that is that not only is that placement not likely to deliver the best bass performance the subs are capable of, it's that multiple subs are normally used to help smooth out the modal behaviour of rooms at low frequency and placing the subs close to the speaker is unlikely to result in a smoothing of the low frequencies over a wider listening area. In fact, if you have noticeable room modes with your current speakers when using them full range without a sub, placing a pair of stereo subs close to the speakers is likely to exacerbate the modal problems you notice without a sub.
In short you may notice some small, occasional benefit from using 2 subs in stereo but it's also possible that 2 subs in stereo might make any existing low bass problems worse. It also requires more work to balance the sound of 2 subs in stereo with your speakers than it does to balance the sound of a mono pair of subs with your speakers. You may find yourself having to do a lot more work to get a good result with stereo subs for very little overall improvement and if you have modal frequencies that coincide with musical notes you may even make things worse. I've tried a stereo sub setup in my HT system with good results but it took a lot of work and it was a fidgety process. In the end I went back to having the 2 subs operating together in mono. It was a lot easier to set them up in mono and any difference in sound quality or imaging was negligible to non-exsistant in my setup. You're more likely to notice a difference between stereo and mono subs if your crossover frequency is set above 80 Hz, especially if it's set at 120 Hz or higher because you're using main speakers with very limited bass capability and/or your room is large and getting good bass down to 80 Hz or preferably lower is presenting too much demand on your amplifiers since the bass frequencies are where the amp has to work hardest.
The subwoofer range may not be mono on 99.9% of recordings because the subwoofer range is variable. It depends on the crossover frequency chosen. Studies have shown that most people are unable to detect the source of sounds below 80 Hz. That means that if you set your crossover frequency at 80 Hz or below, you will probably not be able to detect the source location of the sounds reproduced by the subs but I use two subs in my HT system (a different system to my audio system and located in a different room) and been able to detect the location of one of the subs because the sub was in a corner and strongly loaded a room mode at a frequency below 80 Hz and I was able to detect that that sub was in the corner when the sub was reproducing loud sounds at that modal frequency though I could not detect its location at other times. If you set the crossover at 80 Hz or lower you should rarely be able to notice the difference between 2 subs operating together in mono and 2 subs operating in stereo mode but it may be possible to do so at some times depending on the location of the subs and how each sub loads the room's modal frequencies.
Is it worth using the subs with a stereo connection rather than using them with a mono signal? That's going to depend on where you place the subs and where your listening position is located, plus on the frequency content of the signal going to the subs from moment to moment. Most of the time there should be no significant audible difference, perhaps even all of the time depending on the bass content of the music you're playing and whether or not your room modes coincide with the frequencies of any musical notes. The times when I could tell that one of my subs was located in a corner wasn't with musical notes, it was with sound effects noises like explosions, earthquakes and so on, which were noises with broad band low frequency content that didn't coincide with the frequencies of the notes occurring in the music content of the soundtrack.
I can't say that you will never notice a difference but you may. If you are going to try using 2 subs in stereo mode then the best advice would be to locate them close to the speakers so that the sound from each sub arrives at a very close angle to the sound from their associated speaker. The problem with that is that not only is that placement not likely to deliver the best bass performance the subs are capable of, it's that multiple subs are normally used to help smooth out the modal behaviour of rooms at low frequency and placing the subs close to the speaker is unlikely to result in a smoothing of the low frequencies over a wider listening area. In fact, if you have noticeable room modes with your current speakers when using them full range without a sub, placing a pair of stereo subs close to the speakers is likely to exacerbate the modal problems you notice without a sub.
In short you may notice some small, occasional benefit from using 2 subs in stereo but it's also possible that 2 subs in stereo might make any existing low bass problems worse. It also requires more work to balance the sound of 2 subs in stereo with your speakers than it does to balance the sound of a mono pair of subs with your speakers. You may find yourself having to do a lot more work to get a good result with stereo subs for very little overall improvement and if you have modal frequencies that coincide with musical notes you may even make things worse. I've tried a stereo sub setup in my HT system with good results but it took a lot of work and it was a fidgety process. In the end I went back to having the 2 subs operating together in mono. It was a lot easier to set them up in mono and any difference in sound quality or imaging was negligible to non-exsistant in my setup. You're more likely to notice a difference between stereo and mono subs if your crossover frequency is set above 80 Hz, especially if it's set at 120 Hz or higher because you're using main speakers with very limited bass capability and/or your room is large and getting good bass down to 80 Hz or preferably lower is presenting too much demand on your amplifiers since the bass frequencies are where the amp has to work hardest.
Roon Nucleus+, Devilalet Expert 140 Pro CI, Focal Sopra 2, PS Audio P12, Keces P8 LPS, Uptone Audio EtherREGEN with optical fibre link to my router, Shunyata Alpha NR and Sigma NR power cables, Shunyata Sigma ethernet cables, Shunyata Alpha V2 speaker cables, Grand Prix Audio Monaco rack, RealTRAPS acoustic treatment.
Brisbane, Qld, Australia
