Loudspeaker perception

[graaf]

There is a serious limit to which two speakers can reproduce the spatiousness of a live performance. Thats because good spaciouness - in the room acoustics sense - requires multiple lateral reflection from the non axial direction. This is precisely what the interaural cross correlation measures. Two speaker in the front cannot achieve this without the room adding in the non-coherent lateral reflections.

what are the "non-coherent lateral reflections"? what is the difference between them and "coherent lateral reflections"?

Markus

That early refections help audibility is well know, but not relavent to the music situation.

why? Isn't audibilty about retrieving information? What is the difference between musical information and speech information?

best regards!
graaf

 

[markus76]

Originally posted by graaf in fact omni speakers have best imaging - lifelike, palpable

Razor sharp localizeable phantom sources are part of good imaging and are part of what stereophony is capable of. Omnidirectional speakers destroy that feature completely.

 

[Elias]

Hello,

There is a tradeoff that one has to make here. Good imaging of the recording requires things that minimize the rooms spaciousness - things like narrow directivity will dramatically lower the spaciousness added by the room, it has too, There is far greater direct to reveberant ratio with narrow directivity. But without a narrow diirectivity a small room has a plethora of early reflections and these will ruin the image, albeit the spaciousness will increase.

Seems to me that the solution is obvious - a very live room with highly directional speakers. Seems to work according to all the reviewers that I've had.

Exactly, this is what I'm thinking also about spaciousness and imaging.

Then how to achieve both, you need to have highly directional speakers over the full range of freqs starting from the bass already. This would rule out omnidirectional monopole boxes alltogether.

- Elias

 

[graaf]

Localizable phantom sources are part of good imaging and are part of what stereophony is capable of. Omnidirectional speakers destroy that feature completely.

obviously Your experience with omni speakers is very limited or very unfortunate

best!
graaf

 

[el`Ol]

in fact omni speakers have best imaging - lifelike, palpable

I listened to the MBL bending melons and the Duevel 360° horns and the only plus i see is that the speakers are not localizable. My own experiments with reflector cones gave a too wide and too flat image.

 

[graaf]

Good imaging of the recording requires things that minimize the rooms spaciousness

is good imaging a lifelike imaging or something else?


for lifelike imaging spaciousness is essential, there is no trade-off
virtual image must occupy virtual space, must be surrounded by "air", not hanging in black vacuum

 

[Elias]

Hello,

As I see the picture only tells what will happen when the other source has fixed position at phi = 90 degrees.

At what freq range is this valid?

Can you give the reference, I want to read it all.

- Elias

Elias, 90° is "best":

 

[el`Ol]

Guys, you should come back to facts and avoid nonproven presumptions.
Here are the promised examples:

http://www.mehlau.net/audio/examples/spaciousness/

Best, Markus

I really like the example with the hall. Is it created by convolving? And what was the microphone setup for the impulse response?

 

[graaf]

I listened to the MBL bending melons and the Duevel 360° horns and the only plus i see is that the speakers are not localizable. My own experiments with reflector cones gave a too wide and too flat image.

well, certainly not ALL omni speakers have best imaging
and I haven't said that

on the other hand no need to look far away for other examples - what about CFS, Carlssons and SLS?
CFS are omni, also Carlssons and SLS are closer to omni than to conventional front firing speakers
they all create many many reflections
yet You have said that:

Both CFS and SLS, same as carlsson, give you a better impression that instruments are "really there" than a conventional setup.

or is imaging about something else than impression that instruments are "really there"?

best!
graaf

 

[gedlee]

in fact omni speakers have best imaging - lifelike, palpable

best!
graaf

You can't be serious! This is completely contradictory to what I have found.

 

[Elias]

Hello,

what are the "non-coherent lateral reflections"? what is the difference between them and "coherent lateral reflections"?

Coherence is something like similarity, when your ears measure signal at two different points in space the signals may be more or less similar to each others. Think about longitudal reflections (front-back), both ears have same signal and thus are coherent. Lateral (left-right) reflections will arrive to the ears at different times and are altered by head diffraction in a different way for each ear so they are less coherent.

- Elias

 

[ScottG]

Razor sharp localizeable phantom sources are part of good imaging and are part of what stereophony is capable of. Omnidirectional speakers destroy that feature completely.

A good "omni" (800 Hz up) can easily surpass the localization character of a more conventional speaker.

The trick is to being at least a little bit closer to the speakers than the speakers and you are to any wall.

 

[markus76]

Originally posted by el`Ol I really like the example with the hall. Is it created by convolving? And what was the microphone setup for the impulse response? [/B]

It's just a very dry monophonic recording. I simply applied a digital reverb to it.

Best, Markus

P.S. graaf, ScottG: I guess you have never heard your speakers outside so no reflections disturb localization. Please try it for yourself and you'll know what Earl is talking about.

 

[Elias]

Hello,

I said early on that there is a tradeof that one has to make in a small room to achieve spaciousness AND good imaging. Its a balancing act. And I have also stated that highly directional speakers are the main component of how this balance can be optimized. There appears to be a lot of background information that you are not aware of. Perhaps you should read my white paper at www.gedlee.com as I address many of these issues.

Yes, I noticed you already had the answer before I was refering to some points, thank you and sorry about that. I started reading this thread from the beginning but it's moving faster than me I suppose

- Elias

 

[markus76]

Originally posted by Elias As I see the picture only tells what will happen when the other source has fixed position at phi = 90 degrees.

At what freq range is this valid?

Can you give the reference, I want to read it all.

No, it shows that for any other direction you need a higher level to create the same spaciousness you get from a 90° reflection. So in conclusion 90° is best.

You'll find that diagram in Jens Blauert "Spacial Hearing". One of the best books available with loads of references.

Best, Markus

 

[el`Ol]

You can't be serious! This is completely contradictory to what I have found.

I guess the problem is that graaf believes his and my experiments are omnidirectionals (which they are not). If he had listened to one of the $$$ radials he would be more carful in using this word.

 

[el`Ol]

It's just a very dry monophonic recording. I simply applied a digital reverb to it.

My experiences with the usual synthetic reverb productions are very poor. Would you say reverb devices in general are better in simulating large rooms / long delays? What device / algorithm did you use?

 

[markus76]

What kind of discussion is that? Multiple A/D and D/A conversions and synthetic reverberation can be found on nearly every recording available today – independend of multitrack or live recording. The pro audio folks are much more hands on. For them it's a job and only few see it as an art. And why should they care when in the so called high end sector people still haven't touched even the basics of what stereophony really is.

Best, Markus

 

[ScottG]

P.S. graaf, ScottG: I guess you have never heard your speakers outside so no reflections disturb localization. Please try it for yourself and you'll know what Earl is talking about.

Your guess is wrong then. Try re-reading my first post. (..and yes, I have heard several different types of loudspeakers out in a large field with light wind and modest grass length with battery powered amp/source.)


I well understand what you and Earl have been advocating, (and I certainly don't disagree with all of it), rather I've just heard better and as a result *know* better. (..this is not unlike Jmmlc's reaction statement: "That is not the first time that someone tells me that what I describe cannot be heard".)

 

[gedlee]

Scott, I've heard a few audio systems in my days and by far the best imaging comes from directional speakers NOT omnis. And what you are proposing for how to get omnis to image well is simply not possible in a small room and it is small rooms that I am talking about. The situation is completely different when the room is large enough that the early reflections from the omni are not a problem, but that is not the typical situation.

The reviews of my speakers clearly show that they image as well as or better than anything on the market and they are not omnis.