phusis:
"I find the bass-being-omnidirectional claim too categorial in not factoring in the importance of ambient information aided via a stereo signal, below 80Hz as well."
Hello phusis,
I partially agree with your statement but, based on my experience, I think you have the cause and effect reversed. I know this is a subtle difference but I believe it’s important so I’ll do my best to explain.
First, I believe bass below about 80Hz is omnidirectional (that is, humans cannot perceive exactly where the bass sound is coming from.) Whether you configure 2 subs in a stereo or mono configuration, there is no ambient information existing on bass from about 80Hz and lower.
However, musical signals at or above about 80Hz are directional (that is, humans can perceive exactly where these sounds are coming from.)
I think the critical factor in determining exactly where bass sounds are coming from are the harmonics of the bass notes. For example, a fundamental bass note at 40Hz will produce harmonics at 80, 120, 160, 200, etc. Hz. Once these harmonics exceed about 80Hz, humans can perceive exactly where the sound is coming from. At this point, I think our brains take over and associate the multiple harmonics with the 40Hz fundamental note and the location it’s coming from.
So, I believe there is important bass ambient information aided via a stereo signal but none below 80Hz. Fundamental bass notes below about 80Hz are omnidirectional but the bass note’s fundamentals above about 80Hz are directional and are clues to where the fundamental bass note is coming from.
I believe the above based on my configuration and setup of my own system. I think the bass is the hardest to get right in any room/system so I do that first.
I use 4 subs (each is 28"hx12"dx14"w and weighs 40 lbs) all run in mono and powered by a separate 1K watt class AB amp with the cutoff frequency set at 50Hz. My room is 23’x16’x8’. My hdtv, system rack and components are located and centered along the front 16’ wall. My listening chair is located and centered along the opposite rear 16’ wall.
I optimize the bass at my listening seat by playing music containing good and repetitive bass, placing sub#1 at my seat and walking around the perimeter of my room in a counter-clockwise direction beginning at the front right corner of my room. I walk slowly along the front 16’ wall until I find the exact spot that the bass sounds best to me. Once determined, I relocate sub#1 to that exact position.
I then place sub#2 at my seat and continue walking slowly from sub#1 until the bass sounds best to me. Once determined, I relocate sub#2 to that exact position. This process is sequentially followed until all 4 subs are optimally positioned.
Last, I sit in my listening seat, replay the music with good bass and verify that the bass sounds very good. It’s important to mention that while the bass sounds exceptionally good at this point, I could not determine where the bass was coming from even though there was a sub on each 23’ wall with my listening seat in the middle of the rear 16’ wall between them and 2 subs located along the front 16’ wall.
Next, I optimally position my main L+R Magnepan 2.7QR panels along the front 16’ wall, about 8’ apart and each about 4’ away from this wall into the room, in relation to my listening seat and playing full range but rated bass down to only 37Hz.
Replaying the same music now heard in full range, everything becomes coherent and well integrated. There is a wide and dep soundstage illusion.
My main point being, with the benefit of now hearing the bass harmonics above about 80Hz, I could now determine where the instruments producing the deep bass notes below about 80Hz were coming from within this soundstage illusion. I believe hearing the deep bass harmonics above 80 Hz enables this no matter how many subs are used in a system.
Sorry this was so long but I find this a difficult concept to explain without a lot of detail. I hope I was successful.
Tim
"I find the bass-being-omnidirectional claim too categorial in not factoring in the importance of ambient information aided via a stereo signal, below 80Hz as well."
Hello phusis,
I partially agree with your statement but, based on my experience, I think you have the cause and effect reversed. I know this is a subtle difference but I believe it’s important so I’ll do my best to explain.
First, I believe bass below about 80Hz is omnidirectional (that is, humans cannot perceive exactly where the bass sound is coming from.) Whether you configure 2 subs in a stereo or mono configuration, there is no ambient information existing on bass from about 80Hz and lower.
However, musical signals at or above about 80Hz are directional (that is, humans can perceive exactly where these sounds are coming from.)
I think the critical factor in determining exactly where bass sounds are coming from are the harmonics of the bass notes. For example, a fundamental bass note at 40Hz will produce harmonics at 80, 120, 160, 200, etc. Hz. Once these harmonics exceed about 80Hz, humans can perceive exactly where the sound is coming from. At this point, I think our brains take over and associate the multiple harmonics with the 40Hz fundamental note and the location it’s coming from.
So, I believe there is important bass ambient information aided via a stereo signal but none below 80Hz. Fundamental bass notes below about 80Hz are omnidirectional but the bass note’s fundamentals above about 80Hz are directional and are clues to where the fundamental bass note is coming from.
I believe the above based on my configuration and setup of my own system. I think the bass is the hardest to get right in any room/system so I do that first.
I use 4 subs (each is 28"hx12"dx14"w and weighs 40 lbs) all run in mono and powered by a separate 1K watt class AB amp with the cutoff frequency set at 50Hz. My room is 23’x16’x8’. My hdtv, system rack and components are located and centered along the front 16’ wall. My listening chair is located and centered along the opposite rear 16’ wall.
I optimize the bass at my listening seat by playing music containing good and repetitive bass, placing sub#1 at my seat and walking around the perimeter of my room in a counter-clockwise direction beginning at the front right corner of my room. I walk slowly along the front 16’ wall until I find the exact spot that the bass sounds best to me. Once determined, I relocate sub#1 to that exact position.
I then place sub#2 at my seat and continue walking slowly from sub#1 until the bass sounds best to me. Once determined, I relocate sub#2 to that exact position. This process is sequentially followed until all 4 subs are optimally positioned.
Last, I sit in my listening seat, replay the music with good bass and verify that the bass sounds very good. It’s important to mention that while the bass sounds exceptionally good at this point, I could not determine where the bass was coming from even though there was a sub on each 23’ wall with my listening seat in the middle of the rear 16’ wall between them and 2 subs located along the front 16’ wall.
Next, I optimally position my main L+R Magnepan 2.7QR panels along the front 16’ wall, about 8’ apart and each about 4’ away from this wall into the room, in relation to my listening seat and playing full range but rated bass down to only 37Hz.
Replaying the same music now heard in full range, everything becomes coherent and well integrated. There is a wide and dep soundstage illusion.
My main point being, with the benefit of now hearing the bass harmonics above about 80Hz, I could now determine where the instruments producing the deep bass notes below about 80Hz were coming from within this soundstage illusion. I believe hearing the deep bass harmonics above 80 Hz enables this no matter how many subs are used in a system.
Sorry this was so long but I find this a difficult concept to explain without a lot of detail. I hope I was successful.
Tim