Another recent example is the JBL EON615
The 15" is probably used very high, like 2kHz, so they had to do "something" to widen directivity...
The 15" is probably used very high, like 2kHz, so they had to do "something" to widen directivity...
An externally hosted image should be here but it was not working when we last tested it.
Kenji records in stereo using a Rodes Stereo mic.
At about 43 seconds in (to me at least) it's more than changes in freq. response/directivity and channel balance. In fact the vocals are still remarkably centered despite be so far off-axis (and NOT utilizing a "toe-in" setup).
Instead what I hear is something similar to your "spaciousness" sample.. The vocal doesn't seem to be moving left or right, but it does seem to be placed further back from the loudspeakers.
It also seems to be marginally larger as well - as in ASW. My suspicion is that any sense of enlargement or broadening of the image is from a change in freq. response favoring the midrange (below 900 Hz). It also seems to be a bit more diffuse in character, though of course a larger image should have this characteristic (seemingly occupying a larger physical space).
I do however "pick-up" the additions of reflections as a sort of room-acoustic overlay. This shouldn't be surprising though, it's a recording of a recording - and under this condition your brain can't process-out those reflections.
I also can't say that the reflections aren't the reasons for the changes I'm hearing on this example. However, I can say that under my own tests (which included physical obstacles in front of the loudspeaker in an absorptive room with digital eq. for freq. response correction), that a very similar result occurred (..the added "set-back" effect).
As a general rule: the larger the obstacle, the greater the effect.
More specifically, it's a diffraction effect.
IF we have a lower limit of 2 kHz, then I'd go with at least 1 and a half times the length of 2 kHz, or at a minimum a little over 10 inches. Certainly the shape of the diffraction object should also effect the sound as well as should it's proximity to the driver(s) reproducing that bandwidth. In my case I found the distance of the object from the drivers to be more critical - the closer the greater the effect.
Be sure to adjust the freq. response to your position after doing this, and of course try it in a more high-freq. absorptive environment (..typically curtains drawn) to hear it's effect without reflections (or rather without significant reflections).
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It wasn't provided as determinative proof.
Note the original caveat of "very imperfect" example.
It was provided more as an example of what I hear under better controlled conditions. It was relational, not proof - and at least with respect to the condition of a waveguide and the inability to see the compression driver, it was on-point.
Better still, it provides context to the effect I'm describing so that people (ie. you) can experiment for themselves to see if they perceive a similar effect - or not.
BTW, try a very basic websearch on Rodes Stereo Mic.. it should bring up the one Kenji uses.
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It wasn't provided as determinative proof.
Note the original caveat of "very imperfect" example.
It was provided more as an example of what I hear under better controlled conditions. It was relational, not proof - and at least with respect to the condition of a waveguide and the inability to see the compression driver, it was on-point.
Better still, it provides context to the effect I'm describing so that people (ie. you) can experiment for themselves to see if they perceive a similar effect - or not.
BTW, try a very basic websearch on Rodes Stereo Mic.. it should bring up the one Kenji uses.
Not
Visuals can change what we hear. There are studies showing that the auditory cortex responds to visual stimuli. See "Auditory Neuroscience" by Schnupp.
Not
Visuals can change what we hear. There are studies showing that the auditory cortex responds to visual stimuli. See "Auditory Neuroscience" by Schnupp.
Then try it blind-folded.
..and you can even do something avant garde with the youtube:
-listen to it with your eyes closed.
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But that's the beauty of your own testing - you can apply your own analysis.. and then of course others can tell you just how flawed it is.
Or did you perhaps mean "methodology" as this particular area of study?
^
Your own testing? Guess I missed the documentation. You simply linked a video. Why don't you think about a better way to show (to yourself and others) the "spl gradient" effect?
Maybe recording a speaker might be the right path but miking techniques tend to be quite complex: A Visual Guide to Stereo Recording | Creative Field Recording
...and don't miss this one: Visualization of stereo microphone system AB Base 60 cm Time-of-Arrival Stereo spaced system - Stereo recording angle SRA time difference level difference orchestra angle degrees visualisator - sengpielaudio Sengpiel Berlin
Your own testing? Guess I missed the documentation. You simply linked a video. Why don't you think about a better way to show (to yourself and others) the "spl gradient" effect?
Maybe recording a speaker might be the right path but miking techniques tend to be quite complex: A Visual Guide to Stereo Recording | Creative Field Recording
...and don't miss this one: Visualization of stereo microphone system AB Base 60 cm Time-of-Arrival Stereo spaced system - Stereo recording angle SRA time difference level difference orchestra angle degrees visualisator - sengpielaudio Sengpiel Berlin
Because it's not that interesting to me as something to prove.
More than a decade ago it might have been (..but I doubt it, I went to law school instead). It's sort of "old hat" to me, something I believe I've experienced to my satisfaction as being correct (to at least some extent), while fully realizing that it's not "proven" and that it may be utterly incorrect.
I do however think it's an interesting point of exploration, and so I share what little I can (when I have some interest in the topic).
I don't think however that this particular area is useful for most people wanting more accurate loudspeakers - at least not as most would traditionally define accurate loudspeakers. (..Note that I don't go around suggesting that people design their loudspeakers to include large diffractive devices in front of the loudspeakers - because I'm pretty sure that's not what they are looking for.)
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Now this explains a lot
Perhaps.
(..I should also not that my professional interests aren't stereotypical for that profession, but that they are specifically with respect to defining words to create a condition that is clear and unambiguous - but it takes considerable time.)
but then - giving the recommended size of the thing - isn't it rather about attenuation of the direct sound in the tweeter range than about diffraction?
How much of the direct sound would diffract and how much of it would be just reflected and redirected by an object of the size of more than a wavelength?
Good questions, and unfortunately I don't have any real answers (sufficient or otherwise). Certainly the object's shape and its proximity to the source (and the wavelength involved) will "define" the result though.
I will say that I think of direct sound to include diffraction effects (..its more of an alteration of direct sound - yet still non-reflected on its way to the listener). Ex. the baffle is major source of diffraction yet I think of it as direct sound.
If we want to think of direct sound as "un-corrupted" by diffraction effects, then it's an all or nothing effect within a certain "window" created by the diffraction device relative to its size and proximity to the source.
For instance you can certainly place an object in front of the sound source (a tweeter), so that you only have diffraction over a small angle. Ex. a standard paper-back book a meter away from the loudspeaker's tweeter. In my experience you'll still "focus-in" on the tweeter and any effect is hardly noticeable (if at all). This would of course include any percentage of reflection from the paper-back book.
From an alternate perspective and in relation to reflections: you can place an object so close to the device that reflections from that device really won't occur. Sound is reflected of course, but the freq. hasn't formed to generate a reflection. The effect still occurs.
..and of course this is all in relation to an equalized response at the listening position.
The fact is that you can also achieve image "set-back" by simply lowering spl/intensity (predicated on the bandwidth of the image, and in relation to that bandwidth). Still, when that is done the result isn't quite the same to me - it doesn't have a slight "phasey" character, and it also introduces other artifacts with respect to tonal balance and often image broadening (..by increasing the relative intensity of the lower freq. spectrum).
Another way of widening the image: aggressive toe-in with bent highly reflective surface in-between. Interesting stuff starts at 3:30.
Polished special JBL Paragon and JBL 4341 have been delivered from KENRICK SOUND to Mr. T's room - YouTube
Doesn't seem very hard not to be built by skilled DIYer. Requires dedicated room space, but can be done as part of interior, like creating bent wall. I'd place the tweeters higher from the floor as that's the way we, humans, like it more.
Polished special JBL Paragon and JBL 4341 have been delivered from KENRICK SOUND to Mr. T's room - YouTube
Doesn't seem very hard not to be built by skilled DIYer. Requires dedicated room space, but can be done as part of interior, like creating bent wall. I'd place the tweeters higher from the floor as that's the way we, humans, like it more.
I asked them because it seems to me that relative attenuation of the direct sound in the tweeter range is a common feature of all designs that are known to me as producing this kind of spatial presentation - from stereolit-like one box stereo through all kind of flooders to relatively more conventional designs like Gradient Helsinki.
Yes, many ("radial") designs have a definite loss in pressure above 1 kHz - at least with a traditional 1 meter anechoic measurement.
Here is an example:
SoundStage! Measurements - Mirage Omnisat v2 FS Loudspeakers (6/2005)
Of course the level of reflections (depending on distance from loudspeaker and loudspeaker distance from room surfaces and furnishings), *should* counter this to some extent, but I seriously doubt it's enough to achieve a "flat" response at the listening position.. and likely not even enough to achieve a more common "power response" at the listening position.
You can however eq. under any condition for a "flat" response at the listening position (..which always sounds "tilted-up", with to much emphasis on the treble).
I've found that with eq for flat, the effect persists.
Note that the Gradient isn't like this:
http://www.stereophile.com/content/gradient-helsinki-15-loudspeaker-measurements
Which tends to support the notion that it isn't totally about freq. response attenuation at higher freq.s..
Something I've been thinking about is my description of "diffraction effect".
As I think back, I've never tried this with a "blocker" that only provides substantial absorption in the targeted bandwidth.
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Another method to achieve greater image width can be achieved with a lateral array - even when it's eq'ed flat.
The closer you get to the lateral array, the larger the images.
Of course this holds true for simply the diffraction signature of the loudspeaker's cabinet as well - the closer you get to the cabinet, generally the wider the image becomes (all else equal - as in adjusting for spl and angle differences).
Finally, angle plays it's part here: generally as you spread the loudspeakers further apart (as they effectively move closer to the listener's +/- 45 degree angle), the image tends to get broader and often bigger as well.
In each case the image often becomes more diffuse with poorer localization.
I personally dislike this effect
, particularly with the lateral/horizontal array at most domestic distances from the loudspeaker.- Status
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