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Re: Image perception [message #15001 is a reply to message #14993] Tue, 24 May 2005 08:10 Go to previous messageGo to next message
Earl Geddes is currently offline  Earl Geddes
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Master
I may have missed it but if the imaging is so good at 6' why do you listen further back? Which image do you prefer.

By the Sattelitte radio uses AAC compression from Fraunhofer. The next generagtion of MP3. AAC is why they let MP3 leak into the public domain. They thought the market would jump on the newer better AAC. Big miscalculation.

Re: Image perception [message #15004 is a reply to message #14995] Tue, 24 May 2005 08:42 Go to previous messageGo to next message
Manualblock is currently offline  Manualblock
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Illuminati (13th Degree)
Wasn't there an old song,"Everything old is new again."

Re: Image perception [message #15012 is a reply to message #14977] Thu, 26 May 2005 12:17 Go to previous messageGo to next message
akhilesh is currently offline  akhilesh
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HI Earl,
At GPAF, I heard your speakers the way you had positioned them, from the couch. Then, I moved forward a little, so the apex was at my ears, or a little bit behind. I preferred the imaging in that positiont. I remember telling you that, and you said it was a matter of preference. So, one more data point for you: I prefer being at the apex of the speakers and getting the "headphone effect" i think you termed it.
MAkes it sound more immersive for me.
-akhilesh

Re: Image perception [message #15014 is a reply to message #15012] Thu, 26 May 2005 12:52 Go to previous messageGo to next message
Earl Geddes is currently offline  Earl Geddes
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Master
Thanks

There is a blend of responses, but the far-field one seems to be the preference. All agree that the near-field "headphone" effect is the bigger "wow", but once this effect has been settled into, the far field is prefered as being more natural and listenable over the long term.

I really do enjoy the near-field rock-solid bigger-than-life effect as a once-in-a-while entertaimnment. But I can't listen like that for a long time, it gets unsettling.

Re: Image perception [message #15015 is a reply to message #15014] Thu, 26 May 2005 13:31 Go to previous messageGo to next message
akhilesh is currently offline  akhilesh
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Illuminati (3rd Degree)
Of course, this assumes that one GETS to listen to music for more than a few minutes a day. I listen maybe 30 minutes a day.

So far, I like the "headphone effect" with slightly rolled of highs to assuage the fatigue, if any. Not to mention the euphonic distortion of my 45 SEt amp in the 90-3500 Hz range. Really sounds good to me!
-akhilesh

Re: Image perception [message #15016 is a reply to message #15014] Thu, 26 May 2005 14:47 Go to previous messageGo to next message
Bill Wassilak is currently offline  Bill Wassilak
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Illuminati (1st Degree)
I agree with what you said so I guess I'm in the minority, because I like the near field listening myself. I'm using line arrays and there designed so I'm always in the near field. I don't listen to my system everyday but when I do fire it up I listen at least 2+ hours or more and it dosen't bother me. When you switch media you can really tell a difference on what they did in the control rooms of a studio or differences in acoustics from different halls on live recordings.

Bill W.

Re: Image perception [message #15018 is a reply to message #15016] Fri, 27 May 2005 07:33 Go to previous messageGo to next message
Earl Geddes is currently offline  Earl Geddes
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Registered: May 2009
Master
Thanks

Your message pointed out an error that we are both making in terminology. The listening that I am talking about is the the "direct field" i.e. the field where the reverberant energy is negligable compared to the direct energy. This is quite different from the direct field of the source and they may or may not overlap. So your being in the near field of the line arrays does not mean that you are also in the direct field. I suspect that you are, but I wanted to be clear about this.

Also, the direct field tends to be frequency inpependnet, while the near field is highly frequency dependent. So the two may overlap at some frequencies and not at others.


Re: Image perception [message #15019 is a reply to message #15018] Fri, 27 May 2005 08:58 Go to previous messageGo to next message
Bill Wassilak is currently offline  Bill Wassilak
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Illuminati (1st Degree)
>>So your being in the near field of the line arrays does not mean that you are also in the direct field. I suspect that you are, but I wanted to be clear about this.

I should of made it a little clearer, the line arrays are toed in about 45deg pointed directly at my seating position. So my reverberant energy is very very low just a little off the side walls compared to whats coming directly at me out of the speakers.

Re: Image perception [message #15020 is a reply to message #15019] Sat, 28 May 2005 17:43 Go to previous messageGo to next message
Earl Geddes is currently offline  Earl Geddes
Messages: 220
Registered: May 2009
Master
Your line arrays will reduce ceiling and floor reflection energy, but the horizontal directivity will be almost 360° due to the small size of the drivers. So you are getting a lot of early lateral reflections off the side walls. The pointing angle for these speakers is pretty unimportant because the directivity is so wide.

I am not sure that you can actually claim to be in the direct field of these sources.

Re: Image perception [message #15028 is a reply to message #14980] Mon, 06 June 2005 12:22 Go to previous messageGo to previous message
Earl Geddes is currently offline  Earl Geddes
Messages: 220
Registered: May 2009
Master
Wayne

Missed this post until now.

I have been doing a lot of measuring and investigation as of late and now I think that I have a pretty good understanding of what is required for good imaging and sound quality. Mind you none of this is actually new, it is completely consistent with what I have belived and used all along, but now I have some more data and experience to better quantify things.

There are two aspects of the sound REPRODUCTION problem (note - I am only talking about reproduction here NOT sound reinforcement or musical instruments). These are the transient response and the steady state response - both defined here as in-room responses. For imaging it is critical that the first 5 - 10 ms of the impulse response be reflection free. That is best done with careful polar design, speaker placement and selective room absorption. The image will be degraded for any sound arrivals between the impulse arrival and 5-10 ms. This first arrival must also be fairly flat in freq resp. or it won't sound narural. Make no mistake about it getting these kinds of impulse responses in real rooms is very very challenging. If there is a floor or ceiling reflection, then the image will be less precise and will tend to move in the direction of the reflection, but early lateral reflections will cause coloration and seveer imaging problems - so lateral reflections are worse than vertical ones.

Now to get a natural sound - in a small room - one also needs for the steady state response to be the same as the direct response - nearly flat. This is measured using a spatial average technique to get a good measurement stability. If these two things are achieved, I have found that the imaging is extremely precise and the overall response is quite natural. The speakers will disappear and only a sound stage remains.

Now when one listens very close, then the reflections are brought down by the direct to reverberant ratio increase and the imaging becomes quite precise, but, IMO, not natural. It sounds as if you have been transported into the recording. This will also occur in a very well damped room that had no room reflections to speak of. In these situations only the transinet response is important because there is no real steady state response.

In a lively room, however, where there is a lot of reverberant energy, things are much more difficult to do, but if done correctly they are much more realistic. It then sounds as if the music was moved into the room with you - not you into the recording. The room adds spatiousness and gives an overall perception of the music being in the same space as the one that the listener is in. The steady state response, as well as the transient response are both critical for this to work properly.

This is my current level of understanding of imaging and naturalness as well as the disappearing speaker trick. The speakers will only disappear in the lively room as they will always be obvious in the transient only situation.


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