# New Graph, dip at 200



## Papcody (Mar 6, 2013)

This is my latest FR after running audy and MiniDsp. LCR average with subs:









Anything I can do about the 3 dips, especially the one at 200? what would cause this?

I have 2" panels with a one inch air gap for first reflection points.

bass looks pretty good:









Not sure how to interpret the waterfall yet:


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## prerich (Mar 26, 2008)

What speakers are you using and what frequency are you using as a crossover point?


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## Papcody (Mar 6, 2013)

M&K S-150's across the front and 2x 18" sealed Dayton subs. They are crossed at 80. The S-150's are THX spec'd speakers designed for 80 cross. Audyssey actually wanted to cross them at 70 if I remember correctly which made no sense to me.


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## Wayne A. Pflughaupt (Apr 13, 2006)

Papcody said:


> Anything I can do about the 3 dips, especially the one at 200?


You don’t want to “do” anything about a dip based on a graph that’s averaged from measurements from multiple speakers. Better to look at each one individually – the problem might be traceable to a single speaker, and that’s the one you want to “do” something about, not all of them.

However, unless your AVR has manual EQ that will affect that frequency range, probably not much you can do about it.

Regards, 
Wayne


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## Papcody (Mar 6, 2013)

Here is L,C,R separated. The green is the center, I must have had the volume turned up a little higher when I took that one. But you can tell they all exhibit the same graph characteristics. 









yeah, not sure what I can do to smooth that out or if it would matter that much anyway? its kind of a big dip.

Anything note worthy on the waterfall?


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## Wayne A. Pflughaupt (Apr 13, 2006)

Not really, it looks okay. I typically don’t concern myself much with them because if they’re bad there isn’t much you can about it short of drastically treating the whole room. The exception would be a mode with extended decay that you can apply parametric EQ to, but you don’t appear to have any of that. :T

Regards, 
Wayne


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## prerich (Mar 26, 2008)

Papcody said:


> M&K S-150's across the front and 2x 18" sealed Dayton subs. They are crossed at 80. The S-150's are THX spec'd speakers designed for 80 cross. Audyssey actually wanted to cross them at 70 if I remember correctly which made no sense to me.


very good speakers!!! How old are they? You may have a defective cap in the crossover.

Sent from my iPad using HTShack


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## Papcody (Mar 6, 2013)

Thanks prerich. Yes, i like them and they are pretty old, from when they still made them in the USA. I would have no idea how to check for a bad cap but all 3 have the same FR when tested separately so I would think its something else causing the dip, or they all have a fault...


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## prerich (Mar 26, 2008)

Papcody said:


> Thanks prerich. Yes, i like them and they are pretty old, from when they still made them in the USA. I would have no idea how to check for a bad cap but all 3 have the same FR when tested separately so I would think its something else causing the dip, or they all have a fault...


You're correct!!!! I'm just reaching at straws right now

Sent from my iPad using HTShack


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## JohnM (Apr 11, 2006)

A dip in that region is commonly caused by 'floor bounce', i.e. the reflection from the floor combining with the direct sound. If that is the case it will move a little if you change the height of the mic and may be reduced by a rug or something acoustically absorbent on the floor.


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## primetimeguy (Jun 3, 2006)

Or move you listening position or speakers closer or farther away. Just have to experiment.


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## Papcody (Mar 6, 2013)

Thanks John. I'll try moving the mic around and see where it changes. It's a dedicated theater room so I can't really play around much with the main listening position location (I have two rows of recliners) or the speakers, they're behind an AT screen. Its in my basement, there's padding and carpet down. I'll try and take a picture so you can see the layout. 

Audyssey doesn't seem to be able to get the dip out. I might also run it again putting more focus on the MLP.


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## EarlK (Jan 1, 2010)

Some Reference Material :

*SBIR *

*SBIR & Floor Bounce Calculator*

:sn:


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