# please have a look at my charts



## shambles (Mar 29, 2011)

Hi everyone ,

This is my first attempt measuring my room response using REW.
Equipment used: Mac book pro- motu ultralight interface- AKG C414 (omni mode)- Genelecs 1029A with Sub.

Ive filled up the room with basstraps at all corners, top corners & a cloud to.

Im comparing my charts to some of your charts but i feel that something is not right with my waterfall graph, can anyone pls advise me. it doesnt seem right as the decays are all same! I must be doing something wrong here, am i?

Ive included 20hz-300hz test & 20hz- 20khz test

Thank you for your consultation and time :help:


----------



## shambles (Mar 29, 2011)

Correct me if im wrong, i see alot of comb filtering 2k onwards also a lot of nulls at 150hz, 700- 2k area, 4k,7k 10 k and onwards. Is this right? Please let me know if ive missed out anything else, i am trying to learn to read this chart. thank you


----------



## atledreier (Mar 2, 2007)

use the standard range of 45 to 105 dB for the magnitude axis, as that is the defacto standard at this site. Makes it easier to relate to the other graphs posted.


----------



## shambles (Mar 29, 2011)

atledreier said:


> use the standard range of 45 to 105 dB for the magnitude axis, as that is the defacto standard at this site. Makes it easier to relate to the other graphs posted.


er... im not sure what do you mean? where can i find this option on REW? 
Thank you


----------



## shambles (Mar 29, 2011)

all this is a bit new to me but im trying my best to look for it. also goggled it but no joy ;-(

could you be kind enough to point me the right direction? 

Thank you for your patience and time :help:


----------



## shambles (Mar 29, 2011)

atledreier said:


> use the standard range of 45 to 105 dB for the magnitude axis, as that is the defacto standard at this site. Makes it easier to relate to the other graphs posted.


hey man, is this what you mean? :huh:


----------



## shambles (Mar 29, 2011)

atledreier said:


> use the standard range of 45 to 105 dB for the magnitude axis, as that is the defacto standard at this site. Makes it easier to relate to the other graphs posted.



sorry, trial and error... is this better?


----------



## shambles (Mar 29, 2011)

sorry forgot to attach the graph! :blink:


----------



## test4echo101 (Jul 27, 2011)

Try this,



> Ensure the graph is 800 pixels (or less) in width and that you have used a vertical scale of 45dB-105dB and a horizontal scale of 15Hz-200Hz.
> 
> Read more: Please Read: Posting A Graph - Home Theater Forum and Systems - HomeTheaterShack.com


Test,


----------



## fitzwaddle (Aug 25, 2010)

shambles said:


> Im comparing my charts to some of your charts but i feel that something is not right with my waterfall graph, can anyone pls advise me. it doesnt seem right as the decays are all same!


With your waterfall graph selected, click on "Controls", change "Time Range" from 300 ms to 600 ms, and click "Generate" to regenerate the waterfall graph - so the "mountains" don't get chopped off.


----------



## shambles (Mar 29, 2011)

test4echo101 said:


> Try this,
> 
> 
> 
> Test,


hey shackster thank you for that info...:T

is this better?


----------



## shambles (Mar 29, 2011)

fitzwaddle said:


> With your waterfall graph selected, click on "Controls", change "Time Range" from 300 ms to 600 ms, and click "Generate" to regenerate the waterfall graph - so the "mountains" don't get chopped off.


hey brad thank you for that tip. does this look better now? Thank you


----------



## atledreier (Mar 2, 2007)

Make sure you set the same limits for the waterfall as for the magnitude (frequency response) graph. The different graphs can have different limits. Set it the same way as you set the FR plot limits.


----------



## fitzwaddle (Aug 25, 2010)

Yeah that looks better - although since they're still getting chopped off, you could even go higher on the time range, until they stop getting chopped off - although even as is, you can see that you've got some need for bass trapping to address the model ringing that's showing up (the frequencies that decay slowly in the chart).


----------



## shambles (Mar 29, 2011)

fitzwaddle said:


> Yeah that looks better - although since they're still getting chopped off, you could even go higher on the time range, until they stop getting chopped off - although even as is, you can see that you've got some need for bass trapping to address the model ringing that's showing up (the frequencies that decay slowly in the chart).



hey thanks for the reply, is this better ?


----------



## shambles (Mar 29, 2011)

is doesn't look good does it? it seems like there is decay on the entire low bandwidth! 
or maybe im doing something wrong. does anyone knows if im suppose to calibrate my AKG C414 mic before doing a test? i didnt calibrate the mic for this test.


----------



## test4echo101 (Jul 27, 2011)

shambles said:


> is doesn't look good does it? it seems like there is decay on the entire low bandwidth!
> or maybe im doing something wrong. does anyone knows if im suppose to calibrate my AKG C414 mic before doing a test? i didnt calibrate the mic for this test.


Yes, you need a calibrated Mic. 
I'm not sure but that mic doesn't look like it would be suitable for REW.
It also needs phantom power. 


> The C414 is an industry standard is based upon the C12A which was manufactured in 1962. It's a large diaphragm multi-polar pattern condenser microphone that requires phantom power.


Test,


----------



## fitzwaddle (Aug 25, 2010)

shambles said:


> hey thanks for the reply, is this better ?


You must have changed a different parameter, the time still goes just to 600, and the "hills" are still getting chopped off - try setting it to like 1000ms. Regardless, looks like you need to think about adding significant bass trapping to address the modal ringing.


----------

