Speakers that throw images outside the speaker boundaries: a puzzling comparison

[Deward Hastings]

Crossing steeply at 2000Hz with the RS180 won't do anything to eliminate the excitation of the cone resonance by the higher order motor distortion, even with a notch.

While that's true crossing the RS180 at 2000 Hz also makes it very difficult to avoid its first breakup at 4000Hz . . . and I think that poses even greater problems than the somewhat amplified 5th harmonic. 2000Hz is just too high for the RS180 (and there are other reasons for that as well). It's a supurb driver that people ask too much of . . . crossed LR4 electric below 1100-1200Hz (and I'd still notch it at 4000) it's hard to better.

[mzisserson]

I think we're on slightly different wavelengths.

Both speakers image very well, with very precise placement in both width and depth when the recording contains that information, and more blurry placement when it does not.

The difference is that, for the 8 NFM II's (as well as my 12 DMT II's and most other narrower-pattern speakers I've heard) the stage width is limited by the separation of the cabinets. (With the 12 DMT II's, I solve that by putting them practically on the sidewalls. They throw a wide and stable image that way.) The Q900's are the only narrower-pattern speaker I've heard throw a stage that extends beyond the outer edges of their cabinets.

No, we are there, same book and page. Sound stage between the speakers is what I described as boxed in. A speaker should image well outside their outer edges. If it does not it does not sound very good, no matter how pinpoint it is between, how well balanced the timbre, or how ambient, it is like watching a TV vs. real life. Hi-Def is great but when you turn your head and look there is a wall on each side. Why do that to our hearing when we do not have to? Of coarse this does not mean they should ALWAYS project outside their boundaries, but when the the material is there it better.

[Face]

I've found that Tannoys with the pepper pot tweeter did the outside the boundaries trick better than their tulip waveguide counterparts. No idea why either.

[Face]

For a good example of out of boundaries imaging, check out NIN's "The Slip", track 8, "Corona Radiata". Scroll in halfway and you'll see what I mean.

Tool's track "10,000 Days" will also have 180*+ imaging during the lighting strikes.

[Whitneyville1]

I was at Worst By getting a new modem tonight and I went into "the listening rooms" where "the good stuff" is supposed to be. 95% of it was brands that were house brands, expensive and sounded terrible. When I mentioned that to the kid salesman, you'd thought I'd cast aspersions on his mother, especially when he turned on the Bloze HT 9.2 surround sound. Can you say beam and scream? Well they were loud. I know Joe Average doesn't know what a good still photograph looks like today, and has no idea of what a well composed, well lit and focused movie scene is today, and evidently has no idea what good sound is today either. It's rather depressing.

[Pallas]

FWIW, I'm pretty sure I found my answer. It is probably about directivity and sidewall reflections.

One of my assumptions (that KEF designed for roughly the same coverage angle as Tannoy did, based on the size of the driver and the stated crossover point) was simply wrong.

I asked my friend to measure the length and depth of the Q900's midrange cone (from edge of the phase plug through the end of the surround), and calculated (based on likely measurement error) the coverage angle to be actually somewhere between 120 and 140 deg. I did the same for two smaller-scale speakers of similar design in my home (KEF Q100, KEF KHT3005SE egg) and found the same. So the modern Uni-Q's have a broader, shallower cone than the Dual Concentrics do. Less curved, too. That would logically lead to a wider-pattern waveguide for the coincident tweeter. And, therefore, more interaction with the side walls.

That means the conventional wisdom about early reflections and imaging is, by these observations at least, challenged much less than I thought it was.

For a good example of out of boundaries imaging, check out NIN's "The Slip", track 8, "Corona Radiata". Scroll in halfway and you'll see what I mean.

Tool's track "10,000 Days" will also have 180*+ imaging during the lighting strikes.

The spoken word parts at the end of Natalie Merchant's "Ophelia" is a good one, too. On the Q900's, the first voice sounds like it's well beyond the edge of the left speaker. On the 8 NFM II's, it's placed at the edge of the speaker.

No, we are there, same book and page. Sound stage between the speakers is what I described as boxed in. A speaker should image well outside their outer edges. If it does not it does not sound very good, no matter how pinpoint it is between, how well balanced the timbre, or how ambient, it is like watching a TV vs. real life.

Not really. Once you move beyond the world of cone-dome mushroom cloud midrange machines and into high-fidelity speakers, you'll find speakers that can throw a stable image as wide as you care for them to throw. While it won't go outside the speakers, they throw a consistent and stable pattern, so one can just move them to spots corresponding to the maximum desired image width.

To riff on your TV vs real life analogy, going from something with a dome tweeter on a 180deg waveguide to a properly designed and executed loudspeaker is like going from Don Draper's TV to a front projector with the whole front wall of the room illuminated when the source material calls for it.

[spasticteapot]

To riff on your TV vs real life analogy, going from something with a dome tweeter on a 180deg waveguide to a properly designed and executed loudspeaker is like going from Don Draper's TV to a front projector with the whole front wall of the room illuminated when the source material calls for it.

180 degree waveguide? Wouldn't that be a flat baffle?

[mzisserson]

For a good example of out of boundaries imaging, check out NIN's "The Slip", track 8, "Corona Radiata". Scroll in halfway and you'll see what I mean.

Tool's track "10,000 Days" will also have 180*+ imaging during the lighting strikes.

GREAT tracks for imaging. Peter Gaberil's "Growing up" is amazing, too. Good speaker put the image behind you. Lunchmoney introduced me to some pretty amazing imagaing tracks that are VERY good music as well.

[mzisserson]

FWIW, I'm pretty sure I found my answer. It is probably about directivity and sidewall reflections.


Not really. Once you move beyond the world of cone-dome mushroom cloud midrange machines and into high-fidelity speakers, you'll find speakers that can throw a stable image as wide as you care for them to throw. While it won't go outside the speakers, they throw a consistent and stable pattern, so one can just move them to spots corresponding to the maximum desired image width.

To riff on your TV vs real life analogy, going from something with a dome tweeter on a 180deg waveguide to a properly designed and executed loudspeaker is like going from Don Draper's TV to a front projector with the whole front wall of the room illuminated when the source material calls for it.

Ok, then why to the same speaker throw the same image in multiple, very different rooms? I will use the Spica TC50 for an example. Likely one of the best in this department. I have heard them in about a dozen environments from a showroom to near the middle of a room, close together, far apart etc, and they never fail. I have found many speakers to retain their image if it is a charastic of that speaker.

As for the rest, it is still boxed in...And very annoying. I could name about a dozen $10k/pr+ speakers that easily exhibit this behavior, sad.

To elaborate on your projector analogy: Nevemind the front wall, it is illuminating the side walls too that give you the dimension you are there. If I wanted a flat, widescreen I would go to the local discount movie theater, not IMAX 3d.

[Pete Schumacher ®]

Not really. Once you move beyond the world of cone-dome mushroom cloud midrange machines and into high-fidelity speakers, you'll find speakers that can throw a stable image as wide as you care for them to throw. While it won't go outside the speakers, they throw a consistent and stable pattern, so one can just move them to spots corresponding to the maximum desired image width.

I've heard surround sound on stereo PC speakers, away from walls, that can throw an "image" from any position around my head. If you've never played a first person shooter like Call of Duty, then you don't have a clue at what can be done with a recording to fool you into thinking things are happening all around you, when only two little, crappy, speakers ahead of you are doing the work.

If the recording has it, then the speakers should reproduce it. If speakers will not throw an image outside their position, regardless the recording, they're not very good speakers.

Something else Mike and I agree on.

[Face]

I've heard it with non waveguide loaded tweeters as well.

[Pete Schumacher ®]

I've heard it with non waveguide loaded tweeters as well.

Perhaps, the Tannoy's ain't all they're talked up to be?

[Deward Hastings]

If speakers will not throw an image outside their position, regardless the recording, they're not very good speakers.

Something else Mike and I agree on.

Well darn, that's three of us . . . we should start a club . . .

[Deward Hastings]

I've heard it with non waveguide loaded tweeters as well.

+1

Now there's four of us . . .

[mzisserson]

Five...

[Pete Schumacher ®]

Five...

Can't count yourself twice . . .

[CUtiger]

I've heard surround sound on stereo PC speakers, away from walls, that can throw an "image" from any position around my head. If you've never played a first person shooter like Call of Duty, then you don't have a clue at what can be done with a recording to fool you into thinking things are happening all around you, when only two little, crappy, speakers ahead of you are doing the work.

If the recording has it, then the speakers should reproduce it. If speakers will not throw an image outside their position, regardless the recording, they're not very good speakers.

Something else Mike and I agree on.

+1 Call of Duty has some amazing spatial sound effects, one of the best hallmarks of the game.

[Face]

For a good example of out of boundaries imaging, check out NIN's "The Slip", track 8, "Corona Radiata". Scroll in halfway and you'll see what I mean.

For those interested, this is available in MP3 format for free: http://dl.nin.com/theslip/signup

[Whitneyville1]

Somewhere I said something along these lines...
My really good electrostatic headphones image well beyond my ears and head.

[Face]

Somewhere I said something along these lines...
My really good electrostatic headphones image well beyond my ears and head.

My Hifiman HE-6's do also.