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Old 30th June 2010, 07:23 PM   #4421
gedlee is offline gedlee  United States
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Quote:
Originally Posted by -CGL- View Post
My "on-listening-axis" curve is flat. The power response is falling.
Thats the classic response of a piston source.

Yes, CD speakers do tend to sound bright compared to this is the listening axis is flat. I generally roll off the top end of my personal system a dB or two because of this.

Its obvious why this is - there is simply no type of sound source with this characteristic in nature in a real room. We are used to the HFs rolling off in the reverberant field because of absorption. In small rooms this doesn't happen as much and so a nearly flat power response is deemed as "bright".
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Old 30th June 2010, 07:37 PM   #4422
-CGL- is offline -CGL-  Finland
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Originally Posted by gedlee View Post
Thats the classic response of a piston source.

Yes, CD speakers do tend to sound bright compared to this is the listening axis is flat. I generally roll off the top end of my personal system a dB or two because of this.

Its obvious why this is - there is simply no type of sound source with this characteristic in nature in a real room. We are used to the HFs rolling off in the reverberant field because of absorption. In small rooms this doesn't happen as much and so a nearly flat power response is deemed as "bright".
Yes, the natural stuff. I like to get flat first arraival, the rest may be rolled off (if controlled). Just my opinion after doing this some years . My room is about 40 sqm but I donīt know if thatīs small by Your standards.

BTW, my HF is a "waveguide" from Italy.
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Old 1st July 2010, 12:30 AM   #4423
soongsc is offline soongsc  Taiwan
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Quote:
Originally Posted by gedlee View Post
Thats the classic response of a piston source.

Yes, CD speakers do tend to sound bright compared to this is the listening axis is flat. I generally roll off the top end of my personal system a dB or two because of this.

Its obvious why this is - there is simply no type of sound source with this characteristic in nature in a real room. We are used to the HFs rolling off in the reverberant field because of absorption. In small rooms this doesn't happen as much and so a nearly flat power response is deemed as "bright".
I think it's necessary to look at the CSD. Flat tends to sound right to me. If brightness is due to the room, then probably the best solution is to treat the room. I am very curious though, brightness caused by the room seldom happens unless a large portion of surfaces are metal, glass, or some resonating object in the room.
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Old 1st July 2010, 01:36 AM   #4424
gedlee is offline gedlee  United States
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CSD!? HUUM seems you have suggested that before

What you "hear" when you sit in a room is a combination of both the direct and reflceted sound. As far as spectral balance goes its more heavily weighted towards the reflected sound or "power response" (imaging is more strongly affected by the direct sound for comparison). So it isn't "the room" per see, it's the way the room deals with the power response of the speaker. All of my speakers have a great deal of HF power - far more than is typical, because of the CD nature of the design. This is why they can appear "bright" if set to "flat" on axis. I don't see CSD having anything to do with it.
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Old 1st July 2010, 02:57 AM   #4425
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Inherent in the GedLee argument, is sitting far from the speakers. This increases the power of reflections and brings about the ills that his patented approach rectifies.

Parenthetically, ESL listeners typically put their speakers about 1/3 down the room and hence far closer to mid-area seats. This gained room liveliness without introducing echo-dominance that Earl rightly criticizes.

Sitting a distance from speakers was essential long ago when base noise levels were intrusive especially from over-powered amps and/or pre-amp outputs insufficiently throttled at the amp input.

Likewise, for home theater environments, you can't ethically set up for a single-person listening area. So again, the GedLee rediscovery of toe-in is helpful whereas in a single-person up-closer room it would not serve the same social purpose.

My system does some upper range beaming and it beams right to me and in the power spectrum I like. Sound from the walls (which are very irregular surfaces) slightly adds to the sound in all kinds of wonderful ways (some before and some after the magic 20 ms interval) and it is all softer and following receiving my very direct beamed sound.

CD combined with toe-in can help a lot in some cases. In fact CD doesn't make a lot of sense without toe-in. But for a single-listener in a properly set-up room, not so much.
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Last edited by bentoronto; 1st July 2010 at 03:01 AM.
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Old 1st July 2010, 03:07 AM   #4426
soongsc is offline soongsc  Taiwan
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Some things that I've found in listening tests:
1. If bright sound occurs, and the image depth is lost such that the sound seems to come from the plane of the speakers, and in some occation seem to shift to one speaker only, then normally something within 2K~6KHz can be found causing this. If the sound is a bit on the harsh side, then something above 10K~25KHz is causing this.

2. If bright sound occurs, and the sound seems closer to me than the speakers, then it could be either a specific humb in the SPL or strong early reflection.

3. If bright sound occurs, and the sound seems to come from all around, I have only heard this in a room with more than 30% glass walls(two glass walls facing each other). Sounds really bad due to the high frequency modes.
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Old 1st July 2010, 03:24 AM   #4427
gedlee is offline gedlee  United States
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Originally Posted by bentoronto View Post
But for a single-listener in a properly set-up room, not so much.
While most of what you say has some merit, the idea of design for a single location, IMO, does not. But yes, as one gets closer to the speakers, the direct field begins to dominate and the polar response and room matter much less. But this kind of "into the recording" imaging does not please me, single listener or not. So the fact is that I don't sit close to the speakers because I don't like the effect (it's kind of "headphoney") - albeit some do.

But let's not forget that near field listening requires small speakers and small speakers have dynamic problems (thermally related). And then there is the near field itself - not at all a stable environment.

I've been through all these "alternative" views and setups. I didn't come by my approach by chance. It was well thought out, investigated, implimented and refined and all I can say is that everyone who hears it is impressed. I'm not saying that "I" like it - I'm saying that everyone else likes it.
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Old 1st July 2010, 05:29 AM   #4428
ScottG is offline ScottG  United States
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Originally Posted by bentoronto View Post
Inherent in the GedLee argument, is sitting far from the speakers. This increases the power of reflections and brings about the ills that his patented approach rectifies.
I wondered when someone would pick-up on this.

..it's worse than that actually. (..or rather it *can* be.)

It doesn't just create a problem and then solve it, rather it creates a problem and then potentially compounds it. (..or perhaps is even likely to compound it.)

The problem is one of cross-reflections, often near in time to direct sound.

In other words your right speaker (referenced to you) is aimed at your left side wall. Your left speaker is aimed at your right side wall.

So you have a first reflection bouncing off of your left wall from your right speaker, and the other first reflection bouncing off of your right wall from your left speaker.

This isn't really a problem IF most of each reflection's energy is reflecting from a position a fair bit BEHIND you, where it can "reverberate" out and marginally give the impression of the recreation of envelopment. (..though note that you need a fair bit of room behind you for this to occur, otherwise you can get some pretty strange effects.)

Chances are though that each listener is NOT in a position for this to occur, because again - they are further away from each loudspeaker. In fact just the geometry of the room, (in relation to the angle of the loudspeaker's radiation under this setup) is pretty limiting on where you can sit and still be "in front" of the dominate first reflections. Worse, because of the distance this cross-reflected sound could be arriving closer in time to the direct sound than other setups (..particularly those loudspeakers with nulls at their sides that are well-positioned).

Psychoacoustically this potential new problem tends to create a "limit" on horizontal "spread" or re-created venue expansion and particularly source localization within that venue.. (..i.e it's a higher freq. problem where intensity dominates.) . In fact, it can be a bit odd to hear performers "boxed" in your room (..or sometimes out of it in the depth plane and only marginally expanded horizontally), and yet sense a massive space well beyond the confines of your room because of the information presented with low and extremely low freq.s (..at very low spls). I would note however that this is absolutely ideal for front L/R channels for movies.. needing the *restriction* to match the motion on the "screen".
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Last edited by ScottG; 1st July 2010 at 05:38 AM.
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Old 1st July 2010, 05:15 PM   #4429
doug20 is offline doug20  United States
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Originally Posted by gedlee View Post
It was one of the Truth 203X - other than that I don't know.

Nice attention to low diffraction for a commercial product.

I should mention that in a recent blind listening test it beat out the Orion. The data supports that result.
Dr. Geddes thank you for putting a low cost solution in the measurements program.

Is there going to be some sort of protocol to allow other speaker measurements to be added?
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Old 1st July 2010, 05:18 PM   #4430
-CGL- is offline -CGL-  Finland
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Is there going to be some sort of protocol to allow other speaker measurements to be added?
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