Audio and Video Talk > Acoustics and Room treatment

In room frequency response = sick puppy

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Robert_E:
I just ran REW with a RadioShack SPL meter and this is the sub frequency response at the listening position.


http://img13.imageshack.us/img13/145/subjgd.jpg
I only have 3 spots for the sub because my floorspace is really limited. So is my only option to improve this FR to move the sub around ?

I must say that sub-20hz hump feels :o awesome but the rest looks a bit rubbish

KenMasters:
I'm no expert but I can tell you the steps. First see which of the three positions you're comfortable with gives you the best response from your seating position. Then try treating the room (I'm sure there are members that can help with suggesstions on how to go about it) and finally apply whatever EQ you have at your disposal (in your reciever or an external unit like an SMS-1).

Robert_E:
Thanks Ken, tomorrow is a public holiday here so I'll try moving some stuff around and doing measurements. I think my greatest priority should be to get rid of that 25Hz null.

Hennie:
The peak to peak ripple is very typical, which is why anyone should take measures to improve on it. I would be the least concerned about the 25Hz null and give preference to smoothness from 40Hz upwards. Actually, when excluding the 25Hz null the response from 30Hz upwards does not look too bad given that you have not done any optimizing yet.

Things you can do:

Move the sub around and measure

Add bass traps

Allow overlap between the sub and the mains. Measure the result for the sub in different positions. Change the phase switch and low pass filter control for every position and measure. It is a fallacy that the sub and mains cut-off characteristics should be complementary. Room acoustics screws this up and sometimes an asymmetric crossover, or overlap (too high crossover), or too low crossover gives the smoothest response. Do whatever gives you the smoothest end result.

Add a second sub. Two subs when moved about for optimum location and each individually adjusted will give a substantial improvement over one sub. Adding a second sub and allowing overlap with the mains is even better.

Robert_E:
Thanks for the advice Hennie,

I saw when including the mains in the sweep the graph smooths out most of the dips above 80Hz. I'll play around with the position and phase settings tomorrow and see how it measures.

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