Yes! But so impractical (aka "pain in the butt") to do correctly, that it is never done. Maybe I will start a service to come and while the owner is away make changes to the audio system on random days, to see if they notice.
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kemmler3D
Master Contributor
Speaking as someone who qualifies as both, you're right that blind testing is the foundation.
The good news is that many foundations have already been built.
If someone measures the effect of a DBA (or something else) that shows a clear effect well above known thresholds of audibility, a blind test might still be useful for subjective reasons, but it's not needed to establish the effect is real and audible.
I also don't need blind testing to tell me 0C feels colder than 35C, we just need the thermometer.
As for hype around DBAs I'm not totally sure what you mean. I first heard about them here a good while ago, and the concept seems both sound and appealing to me. It's just ANC (which many air travelers know and love) in a larger format.
kemmler3D
Master Contributor
With that last pic I think it's case closed. Whether over-hyped or not, you don't get that result easily (or at all) with any other setup. 8 subs is cheap compared to how much acoustic treatment that would take...
Lion♡
Senior Member
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@Lion♡ could you please issue a warning to people with epileptic conditions before posting such flashy GIFs? ;-)
As the initial question from the point of understanding acoustics has been successfully answered and the OP seemingly is not capable of explaining how his preferred method is working, I want to come back the the thread´s title:
´DBA (Double Bass Array) - marketing?´
I wonder where this claim originated from. Where was this ´marketing for DBA´ on a large scale? If I recall it correctly, DBA was mainly promoted by people from DIY and installer scene, using comparably affordable subwoofers and repurposed pro audio gear in the beginning to achieve it. Marketing? Rather the opposite, I even know a case of a subwoofer manufacturer specifically not mentioning the DBA capabilities of their built-in DSP x-over in order not to bring people to this idea and bringing their hotline to its limits.
As the initial question from the point of understanding acoustics has been successfully answered and the OP seemingly is not capable of explaining how his preferred method is working, I want to come back the the thread´s title:
´DBA (Double Bass Array) - marketing?´
I wonder where this claim originated from. Where was this ´marketing for DBA´ on a large scale? If I recall it correctly, DBA was mainly promoted by people from DIY and installer scene, using comparably affordable subwoofers and repurposed pro audio gear in the beginning to achieve it. Marketing? Rather the opposite, I even know a case of a subwoofer manufacturer specifically not mentioning the DBA capabilities of their built-in DSP x-over in order not to bring people to this idea and bringing their hotline to its limits.
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olieb
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With that last pic I think it's case closed. Whether over-hyped or not, you don't get that result easily (or at all) with any other setup. 8 subs is cheap compared to how much acoustic treatment that would take...
EDIT: Oh, I was wrong. Lion used 8 subs. But this is not necessary here. 4 subs will create nearly the same result in this geometry.
In some way it can even be described better as two subs with two drivers each in specific positions in the room/on the wall.
The pic shows very nicely the principle of a DBA. The symmetry of the drivers' wall grid avoids the excitation of the lateral (width and height) room modes. And the source-sink concept stops the excitation of the length modes. All this works up to the frequency when the wavelength becomes shorter than the distance between the drivers in the grid
The absence of excited room modes explains the waterfall plot.
This is all simulation of course and in the real world the cancelation will not be perfect, but even getting half there is quite a result. And remember, one needs a rectangular room for this to work.
On the other hand the waterfall of the EQed sub (with cut AND boost) shows how much can be done that way (if you cut and boost this much). In the flat range the result is similar, but one has to remember that 50cm to the side the result may look quite different and the room modes show up with strength. And as soon as the room modes are not fully isolated anymore (above 50Hz) the EQ will not work that well. In a larger room this will start at lower frequency.
Haha, you went the extra mile. I left that as fun stuff for the reader
You could have moved the listening position up and down too, to create even more flickering.
Poor Arindal.
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Lion♡
Senior Member
Sorry. I changed it to a spoiler function warning.
No. You are not wrong. The waterfall is indeed a 4-sub graph. The GIF that was meant to show listening-position variation uses 8 subs.
That is true. It also varies depending on the wall’s reflectivity, and there will be various other factors. Nonetheless, there are many advantages.
Yes i can. But we won’t be jumping up and down when listening to music.... lol
By the way, we can also compare DBA with a conventional few multi-subwoofer setup.(No-Delay)
DBA (4sub)
Multisub 1
Multisub 2
Multisub 3
Since everyone’s environment is different, there may be cases where you need to place four subs, two subs, or only one sub like the OP did. (Of course, even then it might not be in an ideal location, but if there’s no other space available, you may have to place it there.) Each approach has slight differences, and it’s best to make the optimal choice according to your environment.
A Broad Discussion of Speakers with Major Audio Luminaries
Even though I know intellectually the challenges of creating the sensation of a large space using stereo speakers in a smaller room (mine is 13’ x 15’ with a large room opening to the hallway), in practice I have found I can get quite a believable-to-me sensation of listening into a very large...
audiosciencereview.com
Bass and subwoofers
@bmc0 https://github.com/MalcolmSlaney/LoudnessModel This is a loudness model in Python (MATLAB link is included) by hearing researchers who represent the top of the academic field. Might help. In regard to loudness, there's this: https://www.aes-media.org/sections/pnw/pnwrecaps/2014/jj_jan2014/
audiosciencereview.com
Of course, if you take into account in-room bass management and even the stereo-bass discussions that various contributors sometimes engage in, you’ll have quite a few choices and considerations. (And of course, you’ll end up with a headache.
)
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kemmler3D
Master Contributor
Sure, I should have been more specific though.
What I mean is that a DBA can produce a reduction in decay time that is unambiguously audible, as in @Lion♡ 's post. This is not something that can be done with 1, 2, 4, or 64 subwoofers unless they are set up as a DBA. The only other way to achieve that is lots of acoustic treatment, and even then it's not easy. The drop in decay time is IMO what establishes the value of the technique.
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This point should not be taken as an axiom until a full comparative blind test of 2 different systems, with a DBA and with one subwoofer, is conducted. As I have already said, the main difficulty in such a test will be the precise volume equalization, because even slightly louder sounds are interpreted by our subconscious as higher quality.
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DBA marketing... that's amusing. DBA is an inherently unmarketable concept outside of a pretty small niche inside the already fairly niche space of hi-fi. Where is this pervasive DBA marketing, telling people to buy 8 subs immediately, that I have been completely missing?
It's a perfectly valid concept and works quite well. We have plenty of data that indicates that, it doesn't matter if you believe it or not. But it obviously relies on either a lot of DIY effort and know-how or paying for expensive devices and services that implement it for you. Plus, y'know, having multiple subs mounted on two of your walls.
It's a perfectly valid concept and works quite well. We have plenty of data that indicates that, it doesn't matter if you believe it or not. But it obviously relies on either a lot of DIY effort and know-how or paying for expensive devices and services that implement it for you. Plus, y'know, having multiple subs mounted on two of your walls.
olieb
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Yes, there are other options, but all these setups put the subs in somewhat inconvenient places. Unless in a basement there will be a window (and a door) somewhere and to put a sub in the centre of each wall will not work too well with that, certainly not in my room.
4 subs in 1.3m height in the middle of the room are not for everybody either. Not to mention 8 subs.
But putting 4 subs in 1/4 positions on the floor is possible and while not looking as good as a DBA it is not bad and will probably work in non-rectangular rooms as well.
As the examples from @Lion♡ show, it is possible with multiple subs to get a similar solution as a DBA.
A dual bass array in a rectangular room is just a very elegant and simple solution that realises an optimum.
With different positions or in a non rectangular room it gets more complicated and one probably needs individual delay and level (phase?) adjustments for each of the subs.
The only rivaling concept I tried which gives astonishingly similar results compared to a DBA, is a multi-array with cardioid subwoofers (4 or more). It is also less dependent on the exact positions, so inconvenient places can be avoided in most of constellations (sometimes they are necessary, though). We should note that for similar max SPL and subjective decay, it is much more expensive than a DBA.
And could you name the ones having turned it ´into a weapon´ already in the last 20 years, since it is discussed publicly? Me thinks, the list of manufacturers actively marketing it, is pretty brief. Maybe some installers do.
It is not done, though, with an 8x increase in turnover (not profit, please!). Implementing it properly in a customer´s room, is pretty labor- and service-intensive. And you can bet, that any potential consumer being convinced, will probably stick with the most affordable subwoofer solution.
I have done such a listening test a long time ago. The differences in subjective bass precision are even easier to detect than the measurements are suggesting, particularly if listeners are positioned within a range of seats like in a typical home cinema. It is completely unnecessary to conduct a controlled test.
BTW adjusting the correct level for such a comparison, is not as easy. At which seat or with which signals are you planning to do the calibration?
kemmler3D
Master Contributor
I'd say it's a weapon in the hands of salespeople but not marketers.
As a marketer, convincing a normal person, who usually struggles with the idea of 2 subs, that 4-8 subs is really the way to go, would be hard. "You only need to spend 6x more than you planned, and go through a highly technical setup process, and dedicate an entire room to subwoofers, to get good results" is a good way to get someone to give up on the idea altogether.
As a salesperson, with a known-to-be-rich person in my demo room, I could certainly improve my sales with a 1-sub vs. DBA "test". Hearing is believing, after all...
Vladimir Filevski
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No need for "full comparative blind test" when measured difference is 12 dB (!!!) between 1 sub (blue line) and DBA with just 2 subs total (orange line):
It is obvious that no one needs to use his own 2 ears to make an ordinary listening test, let alone "full comparative blind test" when difference is 12 dB- it is completely sufficient to use 2 eyes and the organ between the 2 ears.
(Above measurements are from https://www.audiosciencereview.com/forum/index.php?threads/double-bass-array-experience.19256/ )
As I have already said, you should consult beginners books about audio technology, where you can find, among other things, that people are using microphones for the last 110 years to make "precise volume equalization" without sweat.
The first condenser mic was invented in 1916 by E.C. Wente from Western Electric.
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Yes, even a manual PEQ setup was used to give a similar tonal impression. But you should understand there cannot be any ´precise´ equalization, if the bass performance of one setup, like the mono-subwoofer constellation, is highly dependent on position, SPL and signal´s transient behavior to excite room modes.
It gets revealed easily the moment you use different test tracks in terms of bass character, particularly those with long-standing tones exciting one of the room modes (Madonna´s ´Power of Goodbye´ is an infamous test track classic for this purpose).
It's possible to get a relatively even response in a single listening position with one sub, but it is relatively rare. You are lucky with your room, that is great, but you can't generalize that to mean that no one needs more than one sub.
Moving up to two subs will give a significantly better result (detectable both by ears and measurements).
The benefit from moving from two to four will depend on the room and if one needs to have an even response over a larger area or just a single seat. And you are correct that often the audible differences are not as significant as the measurements may imply since narrow dips aren't necessarily so audible.
Beyond that I am a bit confused that you keep referring to DBA, I have almost never seen anyone market DBA. Are you simply referring to having two or four subs?
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