Steve's Responses, Opinions?

[srckkmack]

First of all, thanks to Home Theater Shack for sponsoring this awesome software! After watching everyone else make measurements, I finally got the equipment together and learned how to use this software. This will really help in making objective measurements to help make improvements to my system.

I made my first measurements. I have a JL F113 sub and I measured the subwoofer both with and without optimization. See below:

JL F113 Optimization Defeated:
f113_defeat.jpg

JL F113 Optimization:
f113_optimized.jpg

First of all, as these are my first measurements, does it look like I have things set up properly?

Since I've never measured before, I think the optimized measurement looks much better than I thought it would. But there appears to be a large peak between 20 and 30 Hz. What might cause this? Is there anything else of significance that I should look at?

Thanks,
Steve

[brucek]

Is there anything else of significance that I should look at?

Steve, you're being somewhat kind to yourself by chosing a vertical scale range of about 85dB (20-105dB). Normally the vertical scale standard we use here is 45dB-105dB. This offers a plus and minus swing of 30dB with a 75dB target. That's a 60dB range.

Your response looks fine though...

brucek

[srckkmack]

Thanks for the quick reply Brucek. I edited the vertical scales per your recommendation.

Do you think that peak between 20~30Hz is a problem?

[JohnM]

The extra output in the 20-30Hz area shouldn't be a problem, it is worth checking that the sub is reasonably matched in level to the main speakers though by making a measurement with both the sub and the main speakers running, that will also show whether there are any problems in the crossover region that might benefit from changing the sub's phase.

[brucek]

I note the narrow dip at ~60Hz has been reduced in the after picture. If you've used a filter to accomplish that, you should consider removing it. The filter to result in that correction could show up as peak a few feet away in another seating position. Generally dips such as that are left alone as far as filter is concerned.

brucek

[srckkmack]

I don't think I have any filters turned on. I have the output of the Soundblaster connected to the LR inputs of the receiver. The reciever equilization is turned off. The only thing in the receiver is that the crossover is set at 80Hz. Should I leave the crossover set here during measurements?

The F113's opimization was on, so could the reduction in peak at about 30Hz have reduced the dip at 60Hz?

Below are a measurement of the mains and of the mains with the optimized enabled sub. Do they look integrated well?

Mains alone:
mains.jpg

Mains amd Sub with Optimization On:
mains_sub_opt.jpg

-Steve

[JohnM]

The integration looks very good.