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Old 2nd July 2008, 06:19 PM   #191
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Quote:
Originally posted by el`Ol
Etienne88,

I tried to find out the tilt angles (inwards/upwards) of the Carlsson orthoacoustic speakers (50/51/52 series). I don´t speak swedish and registering at carlssonplanet failed. It would be very kind if you could help me.

Regards,
Oliver
I can try to help you...
depending on what you want!

Regards,
Etienne
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Old 2nd July 2008, 08:42 PM   #192
graaf is offline graaf  Poland
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Quote:
Originally posted by Etienne88

I choose to have a wide band speaker for simplicity reasons. I wanted first to avoid filter since I have almost no idea how they work, but I would like to learn! So unless you teach me or you serve me the appropriate filter on a silver plate I will live with my speakers as they are!
I can understand that

Quote:
Originally posted by Etienne88

I did not hear anything wrong, no. But I trust better my microphone than my brain!
the problem is that microphone has VERY little in common with our hearing mechanism which is very selective, it integrates the data it receives, it is "active" (as opposed to "passive" reception of sound by a microphone)

read this to find out what is sound from the point of view of psychoacoustics: http://www.moultonlabs.com/more/nick...orf_interview/

Quote:
Originally posted by Etienne88

How do you interpret the impulse response from the lying speakers?
well - I can see NATURAL SOUND that is the first transient and a volley of early (but nor too early) reflections

IMPORTANT is that we don't hear those reflections as separate sound events
for our hearing mechanism it is all ONE SOUND coming from the direction of the first wavefront

the strongest reflection comes over 5 ms after the first wavefront and as You mentioned it comes from the ceiling and it means that it comes in lateral plane from exactly the same direction as the first wavefront, no problem at all
the second in strength is delayed by over 10 ms, no problem at all

best,
graaf
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Old 2nd July 2008, 09:02 PM   #193
el`Ol is offline el`Ol  Germany
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Quote:
Originally posted by Etienne88


I can try to help you...
depending on what you want!

This:
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Old 3rd July 2008, 10:51 AM   #194
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Graaf,
I think you are mistaking sound production and sound REproduction when you speak about natural sound. Early reflections are more than desirable when playing a music instrument. Then, reflections during the 10 to 20 ms after arrival of the direct sound are to be avoided when reproducing sound… The early reflections should be on the record, that's why you don't want them to interfere or to be masked by the reflections from your room.

El’Ol,
Try Espacenet.com to find some patents from Stig Carlsson. Many are in Swedish, but the drawings are international!
I found some that might be of interest for you which are in English: 4,558,762 and 4,475,620.

Regards,
Etienne
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Old 3rd July 2008, 11:29 AM   #195
graaf is offline graaf  Poland
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Quote:
Originally posted by Etienne88
Graaf,
I think you are mistaking sound production and sound REproduction when you speak about natural sound. Early reflections are more than desirable when playing a music instrument. Then, reflections during the 10 to 20 ms after arrival of the direct sound are to be avoided when reproducing sound… The early reflections should be on the record, that's why you don't want them to interfere or to be masked by the reflections from your room.
no, I am not mistaking anything
read the Batzdorf interview with Moulton carefully
I must admit that an analogy He makes with musical instruments is unfortunate as a little bit misleading but there is more than this analogy in His reasoning.

when early reflections are on the record it is practically impossible for them to be masked by room reflections, it is rather that the room reflections carry the information about reflections in the recording making them better audible, INCREASING (NOT DECREASING) the spatial resolution of the system

Read again our (and earlier mine) discussions with Dr Geddes who is clearly of different opinion than Moulton BUT from what He explains follows that it is all very complicated
one must distinguish between reflections <5 ms, reflections 5<10 ms, reflections 10<20 ms and finally reflections >20 ms

it all has been discussed recently on diyaudio between me and Dr Geddes

best,
graaf
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Old 3rd July 2008, 11:36 AM   #196
graaf is offline graaf  Poland
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Quote:
Originally posted by graaf

when early reflections are on the record it is practically impossible for them to be masked by room reflections, it is rather that the room reflections carry the information about reflections in the recording making them better audible, INCREASING (NOT DECREASING) the spatial resolution of the system
post scriptum

in fact there is nothing in reality like "masking of early reflections by other early reflections"
it is all perceived as ONE SOUND coming from the direction indicated by the first wavefront (Haas effect, sound fusion)

only late reflections, echoes, can mask the reproduced sound
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Old 3rd July 2008, 02:21 PM   #197
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Graaf,

I am not at all convinced by the interview you linked to: he tells his point of view without backing it up with tangible data…
Reread post #95 and #97, I hope it will convince you!

El’Ol
If I remember well, Stig Carlsson said in his paper that the drivers should be pointed so that they cross behind the listener. It is somewhere in this paper... From that you can construct speakers adapted to your own listening room!

Regards,
Etienne
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Old 3rd July 2008, 03:46 PM   #198
graaf is offline graaf  Poland
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Quote:
Originally posted by Etienne88

I am not at all convinced by the interview you linked to: he tells his point of view without backing it up with tangible data…
view? data? what data? this is not "His view". This is simply RUDIMENTARY psychoacoustics - something that is not questioned outside of HiFi discussions where it is questioned because rudimentary knowledge is unfortunately ignored in audio industry - engineers are rather interested in what they were educated that is "signal processing in electronic circuits" etc. than in physiology of human hearing

and Moulton is very credible, HiFi loudspeaker business is marginal in His activities, it is His hobby, he has no "marketing agenda"
browse His website

anyway, let me repeat my question:
Did You hear anything wrong which could be attributed to the time domain distortions? What was it?

Of course You have already answered. Nothing was wrong.
The problem is that You simply believe more the apparently "bad look" of impulse response measurement which You misinterpret.

Quote:
Originally posted by Etienne88

Reread post #95 and #97, I hope it will convince you!
ok. let's have a look at them:

Quote:
Originally posted by gedlee

(...)
The "Summing localization" and "precedence" effects are widely overstated in these discussion because they indicate - as you said - the principle direction of the sound perception. They do not indicate whether there is an increase in image blur or coloration, both of which exist for these small delays. SO yes the "principle" direction is set very early 1-2 ms, but the stability and coloration of that image is strongly influenced by the next 8-10 ms. I want a stable and uncolored image, not just a "good idea" of which direction its in.
(...)
Did You hear any "image blur"? Did You hear any "coloration" (apart from attenuated highs)?

notice that Dr Geddes wrote "next 8-10 ms", not 20 ms
look at Your measurement - most of reflections occur after the first 10 ms

"image blur" or "localization distortion" can occur but under specific conditions, absent in the case You have measured, the level of reflected sound would have to be much higher for these to occur

and all those effects were studied by Haas and others specifically for the case of reflections in the lateral plane (side reflections) and not in the vertical plane

Quote:
Originally posted by gedlee
Graaf
I tried to go back and read your first post. It is not clear enough to me to agree or disagree, only that with omni-directional loudspeakers in a small room like that I would expect a whole lot of VER (< 10 ms.) coming from all over the place. You seem to "assume" otherwise. In my rooms I measure the impulse response so I KNOW that my VERs are very low. I think if you measure the rooms impulse response for your setup you will find that its not what you think it is.
Dr Geddes expected "a whole lot of VER (< 10 ms.) coming from all over the place"

well, Your measurement proves that He was WRONG

I can see only three VER <10 ms - NOT "a WHOLE LOT from all over the place" - the first is probably off the floor, the dominating second off the ceiling and the third off the opposite wall or the front wall (?)
just as I had expected
in my proposed positioning it would be even better – reflection off the floor would be practically neutralized and ceiling and front wall reflections would arrive later in time

it looks that Your measurement supports my claims

best,
graaf
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Old 3rd July 2008, 05:51 PM   #199
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Graaf,

About the interview, let me quote a sentence in the answer to the first question: "We have a long history of knowing that we prefer to hear musical instruments in reverberant spaces with reflections; there's no reason we shouldn't hear loudspeakers the same way."
I agree with the first part, I have much more problems with the second part. To me, this is a highly subjective position not supported by any scientific argument...
And it goes on like that for the rest of the interview!

Back to the impulse response.
I mentioned earlier that the program I used with the microphone placed the start of the impulse at the big peak after 4 ms on graph 4. I am wondering if the brain would do the same? I don't know the answer to that question, but:
1) if yes, then you will agree with me that the "impulse" right after 4 ms is followed by plenty of reflections. Which is not what we want!
2) if the brain "feels" the impulse as shown in graph 4, then I agree with you that there little reflections at first, but only for little less than 5 ms. This is not either what we want (which is: as little reflections as possible during the 8 to 10 ms)
My guess would be that the brain put the start of the impulse at the big peak right after 4 ms. It is only a guess, maybe somebody with more knowledge than me could confirm or infirm my guess...

Regards,
Etienne
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Old 3rd July 2008, 08:30 PM   #200
graaf is offline graaf  Poland
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Quote:
Originally posted by Etienne88

About the interview, let me quote a sentence in the answer to the first question: "We have a long history of knowing that we prefer to hear musical instruments in reverberant spaces with reflections; there's no reason we shouldn't hear loudspeakers the same way."
I agree with the first part, I have much more problems with the second part. To me, this is a highly subjective position not supported by any scientific argument...
And it goes on like that for the rest of the interview!
You are right as far as You refer to informal character of an interview, it is INFRORMAL - hence questionable analogies as rethoric means
but the matter of the argument is something else - it is pure science, check some handbooks on psychoacoustics

it is all simple and it works

look - I told You that such positioning would work, Dr Geddes told You that it "cannot work"
I based my proposal on scientific grounds, I knew that it would work - neither the soundstage nor imaging is corrupted/destroyed in such positioning because no physical mechanism for such corruption/destruction exists in nature

You have tried it yourself and now You KNOW that it works

amazingly You still question Moulton position (which is also mine) because "is is not supported by any scientific argument"
and at the same time You quote with approval Dr Geddes who gave no scientific argument for support of His position that "it cannot work"

and You know that He was wrong because You have tested it Yourself
Your attitude amazes me

Quote:
Originally posted by Etienne88

Back to the impulse response.
My guess would be that the brain put the start of the impulse at the big peak right after 4 ms
our hearing works in time domain - "signal processing" starts with the FIRST wavefront, not with the loudest

Quote:
Originally posted by Etienne88

I agree with you that there little reflections at first, but only for little less than 5 ms. This is not either what we want (which is: as little reflections as possible during the 8 to 10 ms)
"little less than 5 ms"? I can see 5 ms or perhaps a little more for the ceiling reflection
(and those time limits of 5 ms and so on were experimentally established for lateral reflections, not vertical)

Can You decribe what You see on the graph?
I am not sure I can read it correctly.

anyway, I ask again: Did you hear anything wrong in terms of spatial reproduction?

best,
graaf
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