Practical application is necessarily a different mindset than research. State of the Industry vs. State of the Art.
While in practice, many subs may be localized due to cabinet coloration or distortion or higher frequency excitation, understanding the cutoffs and whatnot is important for advancing the art. If the late Thomas Dolby had said "It's a chemical system with significant entropy, there's really always going to be noise, let's just work with what we have", one of the great audio innovations would have been left on the table. It's not pertinent today anymore but nevertheless, was an important development.
Our posters here, in sum, represent the biggest audio playground and experimentation facility ever assembled. It's not professionally organized but these discussions may lead to an improved subwoofer technology.
There's a place for ivory towers and faeries, and that is here.
It may take me a while, but I will perform an experiment. I currently have 4 subs in my living room, two on each side. Currently, they're all fed from a mono amp with a combined signal. I have a spare stereo amp that could drive 'em, and can certainly remove the mixing.
I'll report back if there's any noticeable difference...
I'll report back if there's any noticeable difference...
It'd also be helpful to test driver orientation (rear or downfiring vs. forward) and playback level, to test if it's higher freqs from distortion, box, whatever making the difference. If they sound more separated when front firing but not rear.... then filter, distortion, or box may be to blame.
Not fancy, but yes, nice. When you live with a design professional, your home is also a showroom. True, the audio is all pretty well hidden, but there are two amps and a computer running MPD for playing and crossover...
If you're interested in more pictures of our home that we spent 4 years designing:
Dream
If you're interested in more pictures of our home that we spent 4 years designing:
Dream
But it's not that hard to design and build clean-performing subs. Good drivers don't have mechanical noises. Good cabinets are inert and either heavy enough to stay still or filled with dual opposed woofers.
The only hard part is tracking down the annoying rattles in the room.
Depending on the signal there will be a difference but not because bass is now stereo but because modes are driven differently.
There will be frequencies at which the signal is louder at one ear and softer at the other. This doesn't necessarily correlate with the level of the subs, i.e. if a left sub is louder than a right sub then the level at the ears might be reversed due to room resonances.
It ALWAYS comes back to the room . . . the most neglected part in almost every sound system . . .
A friend of mine said that his buddy could tell which sub was on or off, crossed in below 30hz, on program material. These were subs, downfiring, with significant output and presumably low distortion (one of the dual driver RELs I believe) used something like -10dB below the mains as a modal control device for a 20hz room mode.
I know that carries no water here, 2nd hand account, but my friend was performing the testing and is generally a rigorous fellow. He said that while the subs alone couldn't be "pointed to", the tonal balance changed on one side or the other when only one of the stereo subs was on or off.
Just more anecdotal junk to vex Bill.
I know that carries no water here, 2nd hand account, but my friend was performing the testing and is generally a rigorous fellow. He said that while the subs alone couldn't be "pointed to", the tonal balance changed on one side or the other when only one of the stereo subs was on or off.
Just more anecdotal junk to vex Bill.
It was described as a tonal shift tracking towards the sub that was on, but yes, agreed, modal behavior could be the driving factor.
I believed the bass is not directional because of the wavelength theory, so I bought a REL sub some years back. Trouble was the only place it sounded decent was between the main speakers in front of the TV. It was obvious where it was when placed in the corner which was the only place SWMBO would tolerate it staying and I was banned from buying a second one. Also it made the doors and windows rattle in their frames when playing a particularly powerful bass note. I sold it on in the end.
Well, certain frequencies being louder/softer is a tonal shift, isn't it? I guess it was also a sighted test? Once our brain made a decision how sight and sound correlate it doesn't let go easily. See Franssen effect.
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I think there is a certain difference between what the original poster actually wanted to know and the question that he formulated:
Q: Can the human ear really localize bass ?
A: No the human ear can't localise anything !
Q: Can the human hearing really localise bass ?
A: Yes the human hearing can actually localise bass (bass in terms of a family of instruments) !
Q: Can the human hearing really localise the sources of low frequencies ?
A: Well - it depends ! The lower the frequency the more difficult it gets due to the effects that have been mentioned already - like ratio between wavelength and the dimensions of our heads.
I think the original poster had a reason to ask this question. And maybe it would be more helpful to you to ask that question that is lurking somewhere in the background. I guess you'd like to know whether it is worthwile to have stereo bass reproduction. Is it ?
Regards
Charles
Q: Can the human ear really localize bass ?
A: No the human ear can't localise anything !
Q: Can the human hearing really localise bass ?
A: Yes the human hearing can actually localise bass (bass in terms of a family of instruments) !
Q: Can the human hearing really localise the sources of low frequencies ?
A: Well - it depends ! The lower the frequency the more difficult it gets due to the effects that have been mentioned already - like ratio between wavelength and the dimensions of our heads.
I think the original poster had a reason to ask this question. And maybe it would be more helpful to you to ask that question that is lurking somewhere in the background. I guess you'd like to know whether it is worthwile to have stereo bass reproduction. Is it ?
Regards
Charles
I profoundly disagree. This is a DIY audio forum. It should be about building things, not researching the state of the art or cutting edge theories. While that may be OK as a subgenre of the forum, here we should be building and putting knowledge into practice. There is far too much talk, not nearly enough sawdust and molten solder. What's the purpose of a thread like this?
While it is useful to know if pure bass tones can be located or not, it's even more important to know almost no subwoofer will supply pure bass tones. Crossovers and mechanical faults don't allow it.
This reminds me of the story of my friend Jim.
A few years ago Jim set out for a long hike across the some mountain trails. Some miles in he came around a bend in the path and saw a big, brown bear standing there, giving him stink-eye. Jim was surprised, but remained calm. He reached into his backpack and quietly pulled out his local wildlife guide. "Ah-ha!" said Jim. "The guide reports there are no bears in this region. Therefore that is not a bear, and therefore it is not a danger". Thus reassured, Jim proceeded straight on along the path, ignoring the bear. Alas, the bear had not read the guide and was unaware that he was not supposed to be there. He made a tasty snack of poor Jim.
Theory is fine. Reality bites.
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