G

Guest

Guest
<font color='#000000'>So, I happen to question the correctness of information given as truth by gene and hawke and my message just gets deleted instead?

When this certainly confirms that the knowledge base here is sorely lacking.

What I have heard on many other forums is true, the owners here really don't know much about about the physics of acoustics.

Some here should go to school and actually learn a few things. &nbsp;Etiquette is also lacking, quite sad actually.</font>
 
G

Guest

Guest
<font color='#000000'>What I posted:

I'm thinking you guys don't have a clear understanding of the acoustic principles involved here;

&quot;Master Handbook of Acoustics&quot; fourth Edition by F. Alton Everest, page 39 is the ANSI S1.4-1971 graph showing the frequency response of &quot;A&quot;, &quot;B&quot;, and &quot;C&quot; weighting curves on the dB response. &nbsp;

Yes, &quot;C&quot; is the flattest curve, but that is because it accounts for the Fletchur-Munson effect of our hearing ability for low frequencies and thus boosts those frequencies to flat. &nbsp;While the &quot;A&quot; weighting curve starts falling at 1kHz and is &gt;40dB down by 30Hz.

So, this is why an &quot;A&quot; weighting curve with music and HT calibration tones will not work correctly.

To further expound on this premise, the leading maker of high-end calibration equipment states it this way,

THE ART OF EQUALIZATION
FOR CUSTOM HOME THEATERS &nbsp;By Gregory Miller, Gold Line

Gregory Miller is director of audio training for Gold Line, a leading manufacturer of audio calibration equipment. He is certified as a
Home THX dealer by Lucas film. In September, Gold Line Technical Publications will release his book &quot;Guide to Home Theater Analysis
and Equalization.&quot; Miller can be reached at (203) 938-2588
Reprinted from CUSTOM HOME ELECTRONICS, July/August 1997

Every modern processor has a reference specification for finding &quot;0&quot; reference level in a test mode. Then using a sound pressure level
meter, as measured from ear level at the center listening position, the system must produce 75 dB in &quot;C&quot; weighting from every
loudspeaker. If you fail to do this, then speakers that are louder or softer than another in the system will produce a level that your brain
will perceive as coming from an incorrect position.
. . . . . . . . . .
Finally, changing EQ will adjust your system reference level. The last step is always to go into test mode and reset the levels, so that
every speaker produces exactly 75 dB in C weighting from the central listening position. This step is critical to proper imaging, so take a
few minutes to get the levels just right.


<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>
gene : <table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>Quote </td></tr><tr><td id="QUOTE">This message was sent to: Bruce, hawke
Bruce;

Sorry, but you have it all wrong, dBC is designed for flat frequency response within 20-20kHz, dBA is weighed more like the human ear which is exactly opposite of what you said. &nbsp;</td></tr></table>

<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>
hawke : <table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>Quote </td></tr><tr><td id="QUOTE">This message was sent to: gene, Bruce
<table border="0" align="center" width="95%" cellpadding="0" cellspacing="0"><tr><td>
gene : dBC is specifically designed with the Fletcher-Munson curve built-in and was designed for music.
I think we should just assume you got these flipped and end this part of the discussion.</td></tr></table></font>
 
Clint DeBoer

Clint DeBoer

Banned
<font color='#000080'>Bruce,

We addressed this issue with you privately via PM, after which you posted our private discussion in this forum for all to see. Since your post made you look like an a-s-s, and it was meant to be private in the first place, I deleted it. I'll take full responsibility for this.

But since you insist on pushing it and publishing your contentionless &quot;argument&quot;...

First of all, we do home theater SPL calibration measurements with C weighting - that's not the issue. You are trying to confuse what the weighting is based on with what our ears actually hear (the compensation basis vs. the weighting itself). No one said we do SPL calibration with an A weighting scale. You have made a straw man argument. Congratulations you won a point you made - one we weren't even discussing.

Your desire to appear knowledgable about this is causing you to create a problem where there is none. If you remember, the original statement you had a problem with had to do with going deaf from listening to loud levels (based on a post from another member, I might add). For some reason you launched into dBA vs. dBC as if, without any reference whatsoever, levels rated one way could hurt you and another could not...

I'll leave this post where it is. You obviously seem to feel that your argumentative nature and desire to create a contention where there is none should be here for all to see...

[Edit: typo]</font>
 
gene

gene

Audioholics Master Chief
Administrator
<font color='#000000'>Attention Audioholics forum members;

The original posts in this thread &nbsp;now titled &quot;Guest&quot; were posted by Bruce. &nbsp;By his request, and because of his blatant flaming and personal attacks he has committed against other forum members and our staff, I have terminated his account and posting privledges on this forum. &nbsp;In the process of doing so the forum software has renamed all of Bruces subsequent posts to &quot;Guest&quot;.</font>
 

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