The below graph is a response graph only. Max SPL should see about 130 dB at the 10-20 Hz range.
Black line is native with left and right mains only: Harbottle C7, no tuning or correction of any kind.
Red line is tuned with 21 inch Funk Audio subs.
You can clearly see a room null between 50 and 100 Hz where the response drops a total of 20 dB.
20 dB loss over a 50 Hz bandwidth... not exactly a small amount.
By using the system to its full potential and by using good crossover technique, the null is now gone and the system has a 21 dB gain in its place.
This is not done by boosting the signal, this was done by me knowing how to get the most from my equipment. I can not emphasize this enough... The only tuning boost that you see in the red line is:
55 Hz, +2 db with a Q of 5, Bell filter
20 Hz, +6 dB with a Q of 14, Low Shelf filter
97 Hz on the subwoofer (10 Hz above the crossover point), -12 dB with a Q of 12, Bell filter
Main speakers: 100 Hz no description on the AVR.
Subwoofers: 87 Hz @ 18dB Butterworth.
What I personally find the most interesting is how you can clearly see the effect of the crossover extending up past 160 Hz... an octave above the subwoofer. This is called a harmonic, and solid positive effects seen within the harmonic range of a given crossover point are not a coincidence, they are the sum of the subwoofer and the main speaker working together in unison.
In fact, the positive effects of the subwoofer can be seen as far as 300 Hz, which is right in the two full octave range of the subwoofer crossover point! Also, not a coincidence.
What is the client left with?
In this case we were able to dial in the tune and his needs for 3 room tuned presets that leave about 10 dB gain on the subwoofer channel in his AVR. That is a lot of headroom.
The mains are running stress free and fully optimized. So the net result is a system that attacks like a giant wall of sound with effortless force and punishing ability. So from Edge of Tomorrow to Michael Jackson, his wife, kids, and he are all "very very happy".
If you are on the fence at all about getting your Funk Audio or Harbottle Audio system tuned... Don't be. This kind of result is very common for average build quality rooms.
If you have a Funk Audio sub and are not getting this kind of result, contact me.
If you have a passive Harbottle product and are not using Harbottle amplification with DSP, think if this kind of result would be something that fits your audio goals.
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