Reading here, I came across people who suggested that NULLS in the room cannot be corrected no matter what type of equalisation is employed. So, only option was to move the sub to some other position. But I kept thinking on other lines.
Yesterday it just occured to me why not keep subwoofer distance constant and play around with distances of each individual speaker.
Coz I though what if I get married to 5 women at the same time? I am only one person.....how would I be able to keep all the 5 women happy? It is not possible. So, I thought why not all the 5 women do their own tiny bit and keep me happy? So, I came up with the idea of adjusting the distance of each individual speaker, One At A Time, and match the phase with the sub at my reference volume in my 5.1 setup.
This is what I did;
- Disconnected all the speakers except one.
- Set the SPL meter on tripod at the main listening position (Slow response/c-weighted).
- Set the crossover on avr at 80hz, played an 80hz tone, and measured the SPL.
- Then I adjusted the distance of that particular speaker where I got the max SPL.
- Repeated the above steps for all the 5 speakers independently. All the distances were now way off the actual physical distances.
- The NULL at 71Hz, which measured -17dB below my reference SPL now gave me -3dB below reference SPL. Which means that by time aligning my speakers with sub, I automatically removed a NULL from my room. Also, the post measured FR showed other dips and peaks far less pronounced.
- At the corssover region, my new spl is 4dB hotter than before.
- The overall sub response is smoother than ever after setting the filters on BFD. I didn't have to do much.
- The bass in music is very loud, snappy, and fast with no hint of boom at all. Same goes for movies and I get a very loud and smooth response down to 23hz without straining the amp on sub. Also, it is very seemless blending.
- In a nutshell I am completely blown away with how my system is performing now. I never thought how important time alignment was in a system.
Going by the book, I wasn't getting anywhere by keeping the actual physical distances of speakers in AVR. Coz that distance setting was from the speaker to the main listening position, whereas the speakers have to be in sync with sub from their own actual location against the location of the sub. Going by the book was causing misalignment in time domain causing huge peaks and dips in sub response.
Any comments on calibrating the system this way??? Coz I did not do it the old orthodox way