# Can Someone help me read my graphs



## Drumtapper (Oct 27, 2010)

I have completed my measurements. I would like some help on reading my graphs if theres any on here that can help me break them down. Thanks in advance!!!!!!!

Here are is my 2.1 set up Full Range with all speakers 

1 SPL 








2 Waterfall 








3 RT60








Now I'm putting up Left and Right speaker measured by them self

1 SPL Left 1/6








2 Waterfall Left








I'm gonna put up Right speaker and then The Sub by it self in the next post


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## Drumtapper (Oct 27, 2010)

Here's the Right Speaker

1 SPL









2 Waterfall









This is the Sub by it self

1 SPL









2 Waterfall









3 RT60 









Can anyone help me break these graphs down THANKS


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## laser188139 (Sep 19, 2009)

For the full range measurements, what microphone were you using? Did you purchase a mic with its own individual calibration file? 

I ask because, if you are using a Radio Shack meter, you might want to ignore the peak and all the behavior you see above 4kHz. 

Bill


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

Drumtapper said:


> Can anyone help me break these graphs down


Like Bill said, the accuracy of your full range measurements depend on what mic /calibration you’re using. We’ll wait to hear back from you about that.

Waterfall graphs are only useful for low frequencies – below about 300 Hz or so (someone correct me if that’s the wrong upper frequency).

Your sub graph is curious. It’s dead below ~36 Hz, which is rather poor extension. A good home theater sub should get down to at least 25 Hz. In addition, the two narrow depressions at ~60 and ~80 Hz are nulls, and indicate that a better location would be in order, if that’s an option. Also, why is your sub still going strong at 200 Hz? Is there no bass management or crossover on line?

Wayne


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## glaufman (Nov 25, 2007)

I would also find it helpful if the frequency axis of your waterfall plots were log, not lin.


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## Drumtapper (Oct 27, 2010)

I did use a Radio Shack SPL Meter and i will post the Waterfall with the LOG my mistake I thought it was. I have a KRK ten nch woofer it goes down to 50HZ but when i took the measurements I left it at the crossover at 80hz. Should I have to the measurements different


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## Drumtapper (Oct 27, 2010)

ok Here are the ssme Waterfall graphs from up top with the LOG setting

FullRange all 2.1









L&R only 









L only









R only









Sub only


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## Drumtapper (Oct 27, 2010)

I remeasured my Sub only with the crossover at 30HZ here are the graphs. The graphs uptop sub was done at 80Hz crossover

1 SPL Sub only 









2 Waterfall









3 RT60









Can you all tell me what these look like and did I do the first measurements wrong. Wayne I can't understand why the Sub is still working after 200Hz also. I dont have a Bass management all I have are my two mointors running to my sub and crossing over at 80Hz


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## laser188139 (Sep 19, 2009)

Drumtapper said:


> ... I can't understand why the Sub is still working after 200Hz also. I dont have a Bass management all I have are my two mointors running to my sub and crossing over at 80Hz


It's not clear to me how you have it wired. Do you have the monitors between the AVR and the sub, so the sub is receiving the high level input that is also being sent to the speakers? Or do you have the sub between the AVR and the speakers, so the speakers are receiving the high level out passed on from the sub? 

What do you mean when you say the graphs were sub only, when you write that you don't have any bass management? Are you saying that you have the speakers set to Large in the receiver? Does the receiver have an LFE out, and are you running this directly to the sub, as well as connecting the sub's high level inputs?

Most subs implement, in their crossover, only a low-pass filter. On their high level inputs, the entire content is passed on to the high level outputs, and the filter is used only to copy a part of that content for the sub itself. So you might be measuring the upper frequencies coming from the front speakers, but you should hear that and notice it. 

Some subs implement their crossover only on the high level outputs. So if your front speakers are configured to Small in the AVR, it will be the crossover in the AVR that will split the content between the sub and the fronts. At frequencies above the crossover, you should hear most of the content from the front speakers. 

The only way to have a real sub-only measurement is to disconnect your front speakers, or if you have a receiver that supports A and B front speakers, switch to the B front speakers if you have nothing connected to the B outputs. 

Bill


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## Drumtapper (Oct 27, 2010)

Thanks for getting back with me I have a studio set up. I have two mointors and a sub. The way my KRK mointors are hooked up is I have a Input XLR cable going from each monitor running to a XLR jack L & R Output on the back of the sub. Then I have two Balanced 1/4 L&R going to my Mackie BigKnob level control. I have my Sub set at 80Hz crossover and in phase with the monitors. What I did was just turned of the monitors and left the sub on for the sub only test. I might should just unhook the monitors and then test the sub to be certain


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