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Old 2nd April 2013, 11:21 PM   #2721
ScottG is offline ScottG  United States
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Hey, you went looking for spectrograms. It was a helpful key word for your search, no?

Did you find the one with bass guitar showing the high 2nd and 3rd order harmonics?
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Old 2nd April 2013, 11:22 PM   #2722
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Rudolf,

Thanks for shorter window. 7ms reflection free places microphone very close for avoiding floor signal.
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Old 2nd April 2013, 11:54 PM   #2723
ra7 is offline ra7  United States
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Sorry for the multi-quote.
Quote:
Originally Posted by Rudolf View Post
My room is 5 x 4 m. 100 Hz is 3,4 m wavelength. If both speakers are at leat roughly symmetrical to the room axis, L-R should produce almost complete cancellation in that range and below.
Complete cancellation means what will show up on the graph is only the reverberant spectrum. If that's what you mean, then yes.
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At high frequencies a large part of the sound arriving at the mikrophone will be from boundery reflections - which are much harder to be kept perfectly antiphase at small wavelength.
Again, I think you are confusing cancellation with what is left on the graph. Cancellation is of the direct sound. What is left is reflected sound. There should be no impulse if you achieve perfect cancellation, just random noise-like spectrum in the impulse window that are the reflections.
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If your speaker has rising directivity, the ratio between reflected sound and direct sound will become lower with rising frequency, resulting in better cancellation.
Agreed. But I think in your earlier post, you mentioned constant directivity.
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Have you ever done L+R versus L-R measurements outside your sweet spot? From what you report about your listening impressions, they shouldn't deviate much from the sweet spot measurement.
Rudolf
No, I haven't. Outside the sweet spot, I wouldn't expect perfect cancellation because I would be closer to one speaker than the other and the level would not be the same. BTW, my speakers are only constant directivity above 1 kHz. As much as I argue for directivity below 1 kHz, I don't have it currently
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Old 3rd April 2013, 12:27 AM   #2724
FrankWW is offline FrankWW  Canada
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Quote:
Originally Posted by ScottG View Post
Hey, you went looking for spectrograms. It was a helpful key word for your search, no?

Did you find the one with bass guitar showing the high 2nd and 3rd order harmonics?
Yeah, and I haven't forgotten you trying to mark me into no upper harmonics down low in bass/baritone register - even singing the low C the only way there is no higher harmonic material is when the sound is so quiet as to be useless. Any zip at, and there's harmonic stuff over 1 kHz.

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Old 3rd April 2013, 02:24 AM   #2725
ScottG is offline ScottG  United States
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Quote:
Originally Posted by FrankWW View Post
Yeah, and I haven't forgotten you trying to mark me into no upper harmonics down low in bass/baritone register - even singing the low C the only way there is no higher harmonic material is when the sound is so quiet as to be useless. Any zip at, and there's harmonic stuff over 1 kHz.

Naughty, naughty
Ah, yes - but the vocal test was *humming* and at a low enough freq. that specifically didn't register with much output at 700 Hz (or above). (..I've done that before - so I know it can be done.)

It's largely a matter of which freq. is played for instruments with substantial harmonics (..a pure synth is one of the few that wouldn't meet this qualification, but then again - pure synth's playing that low in freq. are pretty rare.)

The real "kicker" however is - just what level is significant? That's the really important part.

I don't remember that at all. (..it's been over a decade and half since I read research on this topic. ) I also don't remember if with certain instruments we might focus more on the harmonics, and which harmonics, than the fundamental.

Lot's of questions.

Anyway, here is the bass guitar (Fender) link with a few other bass instruments:

Audio Spectroscopy in the Analysis of Stringed Instruments and Their Components

Don't know what the amplitude difference is in the shading, but at least with the Fender at 55 Hz, there isn't much at all above about 850 Hz - that is still above 700 Hz though. BUT the output above perhaps 600 Hz or so may not be significant. Don't know.
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Old 3rd April 2013, 07:37 AM   #2726
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Default pseudo hulabalaoo

how about we stick to talking about david's 700hz shait and trying to understand obviously what his test conditions were&his conclusions. (and try to note that even blumlein had something negative to say about pan-pots)

and please stay away from sociology studies of scientific knowledge, unless your willing and daring to venture into philosophy of science... +its really not relevant to this issue...
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Old 3rd April 2013, 08:54 AM   #2727
soongsc is offline soongsc  Taiwan
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Quote:
Originally Posted by ra7 View Post
Perhaps you missed this post:
Linkwitz Orions beaten by Behringer.... what!!?

Note Pano's exceptionally high DR ratio.

I thought this was the most important discussion in that giant thread.
I must have missed it before, but I totally agree. Thanks for pointing it out.
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Old 3rd April 2013, 09:48 AM   #2728
Rudolf is offline Rudolf  Germany
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Quote:
Originally Posted by ra7 View Post
Complete cancellation means what will show up on the graph is only the reverberant spectrum. If that's what you mean, then yes.
I thought that the measurement knows no difference between direct and reflected sound. "Complete" or "perfect" cancellation would be (L-R) at least 20 dB below (L+R) for me. About -20 dB is the hearing threshold for some/most effects in the direct/reverberant field.
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Again, I think you are confusing cancellation with what is left on the graph. Cancellation is of the direct sound. What is left is reflected sound.
If that is the official definition of cancellation, you might exchange attenuation for cancellation in my last post.
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Agreed. But I think in your earlier post, you mentioned constant directivity.
Well, my speakers have constant directivity up to 9 kHz. I believe that your and panos speakers have narrower directivity in that area. My speakers are even "wider" if we look at 360 and not 180 only. So my reflections have a harder time to cancel one another in the L-R measurement.
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Outside the sweet spot, I wouldn't expect perfect cancellation because I would be closer to one speaker than the other and the level would not be the same.
I always thought that this level balance was an indispensable requirement for exquisit imaging. Didn't you claim that for your speakers for an extended area?

Rudolf
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Old 3rd April 2013, 09:53 AM   #2729
graaf is offline graaf  Poland
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I wonder whether what's beyond The Ariel would be beaten by Behringer
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Old 3rd April 2013, 11:01 AM   #2730
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Quote:
Originally Posted by Barleywater View Post
Ask yourself some genuine questions, work out an experimental design, pull out a measurement microphone, and perhaps grab a tape measure. Generate some real data. Analyze it.

Your don't seem to like all the data and information you receive from others.

Build nice simple 3" FR pipe mounted (and well damped), point them at the ceiling and have a good listen. Ignore frequency response/timbrel issues and concentrate on the imaging performance. This should be easy to do.
Cut the crap and stop making things up. You don't know anything about me and yet you act as you would. I have a speaker that is more uniform than anything you guys showed.
I did and do extensive tests and have tons of data but things aren't as simple as some here try to make it look.

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Originally Posted by Barleywater View Post
Easier than clogging up thread with snippy retorts.
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A small head is fundamentally more absorptive than a big head, and the small head fills up with noise quicker.
Practice what you preach!
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