After REW......should I be concerned about?

**clubfoot** · **04-18-07, 04:48 PM**

I used REW to find the best location for my sub (f113), which coincidentally is where I had my previous sub (definitive tech).

This is the plot of my sub alone with ARO

This is the plot of my sub with mains set to small after ARO

This is the plot of my mains in Direct mode

My question is should I be overly concerned with the dip at 50Hz with mains set to small and sub, or is it narrow and shallow enough that it has little influence? I have polarity, xover and phase switches but they made the plots look worse! I mean the system sounds very good and does not seem to be missing anything.

**brucek** · **04-18-07, 04:59 PM**

Quote:

This is the plot of my sub alone with ARO

What's ARO ?

You could benefit from some equalization of your sub at ~40Hz and ~80Hz....

brucek

**clubfoot** · **04-18-07, 11:05 PM**

Quote:

brucek wrote:

What's ARO ?

You could benefit from some equalization of your sub at ~40Hz and ~80Hz....

brucek

Automatic Room Optimization. The sub is a JL Fathom f113 and the ARO finds and adjusts one frequency that it desides is problematic. The sub has a switchable 12db and 24db adjustable xover, but when I tried different settings it added dips in the response. I can try the xover again using just the sub plot without the mains, and then see how it influences the overall response. From what you're saying the idea is to have the sub plot follow the ideal slop as closely as possible?!

**brucek** · **04-19-07, 08:02 AM**

Quote:

From what you're saying the idea is to have the sub plot follow the ideal slop as closely as possible?!

As a first equalization it's usually best to equalize your sub alone and try and come close to a standard crossover target. Then when you add the mains you have the knowledge that the sub doesn't have any huge peaks or dips by itself that are adding to any new problems you experience with the addition. At that point a small phase change or time delay or placement can usually help.

It seems that you have a peak at about 40Hz that is caused solely by the sub and could be corrected. You also have a peak at 80Hz that may be correctable by phase, but should be likely addressed by equalization since it's showing quite prominent in the sub only graph.

brucek

**clubfoot** · **04-20-07, 04:49 AM**

Thanks for the suggestions, I will spend sometime today playing with the sub to see if I can get rid of those two peaks at 40Hz and 80Hz without the mains.

**clubfoot** · **04-20-07, 09:07 PM**

OK what's your opinion of this plot? I don't have a BFD so I'm trying to find the best location. I'm still going to look for one but I would first like to get the best location.

**brucek** · **04-20-07, 09:50 PM**

To compare graphs use the All Measured feature. It will help in your comparisons. You can take 9 readings and put them all on the same plot and then picking the best is easier..

brucek

**clubfoot** · **04-21-07, 07:38 AM**

I did the comparison and I eliminated the peak at 40Hz (purple) that you pointed out and tried to stay as close as possible to the ideal trace. However, now I have a dip at 60Hz and a peak at 50Hz(blue)

What I'm trying to understand from reading posts on this forum concerning sub plots is what to avoid, like dips or peaks in what regions where they have the most audible influence. I can see the sub signature in the 15Hz to 40Hz region and I've put the sub where I sit and moved the mic around the room to find the best location.

Here is the final plot I think I can trim out the peak at 50Hz:

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