setting up a 7360 sub for 8351 speakers.
My question is how to combine the graphs for 7360 with 8351. GLM software does not produce a final combined graph. The 8351 results look the same as before the subwoofer. Looks like a full range sweep result.
(1) Then the sub has another sweep result, with a massive dip at 80Hz. Is this is crossover? I don't think my room has a null so big.
(2) Then the graph goes back up after the crossover? Is this information in GLM graph just for fun or is the bass in my room really that messed up? Is subwooder is outputting all those frequencies in the GLM graph (i.e. 120Hz and above)?
(3) So what is the the combined effect of the 7360 + 8351? GLM doesn't seem to give a final result of the 2.1 system for L + R. For example, if I use another room measurement software, it would not recognize the 7360 + 8351 as 2 different things. I'd get the '2 final results' of L and R speakers.
GLM will calibrate the products without the x-over enabled. The null visible in your sub's response is your room, so the best course of action now is to investigate other subwoofer locations or listening locations. As you can see the null is not present in your monitors, so by moving your sub, you may be able to reduce this cancellation.
Once you are happy with the responses, you can then select a crossover that works for both the monitors and sub.. As an example let's assume that you have no option to move your sub or listening position, i would set the crossover somewhere around 70Hz, this would provide a nice frequency response for the system, it is also critical to run auto-phase once these settings are applied.
As a side note if you grab the little button below 400Hz, you will be able to enlarge you plots to see more resolution in the plot.
1038: Hi eljf, GLM will calibrate...
GLM will calibrate...
Good advice 1038. That's really helpful.
The previous sub measurement was with the sub in middle, between 2 speakers. Now I've moved it to the right of the middle, closer to right speaker.
Here the null seems worse, but the frequencies below the null are better (closer to 0). Your idea is to put the cross-over before the null. So in this case, although the null is bigger, the important part of the sound is better? Is that a correct way to compare the graph result now vs. above?
The cancellation is still a massive problem, can you post a pic of your room?
Is the subwoofer hard up against the wall?
1038: The cancellation is still a massive problem, can you post a pic of your room? Is the subwoofer hard up against the wall?
Hi 1038. Thanks for helping here.
PIC stereo: can see L + R + sub behind desk on floor + left wall + right wall + front wall (& windows)
PIC back: the back wall. DIY insulation panels (mostly black colour). Some diffusion.
PIC distance from wall: I have black DIY panels on front wall. The sub is as close to these panels as posible. The actual wall is about 11 inches behind the panel. Panel is 10 inch thick + 1 inch air gap to wall.
PIC sub graph: The worst of the dip is -14.7 @85Hz, with the 0db crossing to the left of that @75Hz (green line).
PIC L+R: graphs for L&R