crwilli
Active member
- Thread Author
- #1
I just completed a full two-day tuning session on my system and wanted to share the highlights. Everything was done one variable at a time and verified in REW (SPL, Group Delay, ETC). All analysis and number crunching was done by ChatGPT. It also required less measures as it can easily interpolate within the extremes that were measured.
Full Listening Triangle Shift
To keep things simple, I fixed the LP and mains triangle to remove their interaction as a variable at the beginning. The work started by moving the entire listening triangle—both mains and the LP—forward into the room:
• +12”
• +24”
This required creating an accurate grid on the floor using starting ‘triangle’ as the baseline and coming to an understanding with Chat what the reference points were. E.g. where was 0,0, what was the left wall, front wall, right wall and back wall. That took longer than I thought it should.
After measuring the baseline and both moved positions, +24” was clearly superior: smoother bass, cleaner GD, better ETC symmetry, and a deeper, more stable stage. This became the new reference geometry. I accepted Chat’s analysis on this. Embedded in this was it crunching all that data to see the differences AND knowing what is better and what is not. (Side note: I have run REW for years and mostly used the dB v Frequency graphs to guide my tweaks. Mainly because I didn’t really understand what Group Delay or Implulse or ETC were telling me. Chat does understand them and that lead to a better result)
⸻
Toe-In Optimization
With the triangle fixed at +24”, I tested three toe-in offsets: numbing the rear of each speaker outward by these distances and letting Chat calculate the angles, it was simple.
• 1.5” (≈3.6°)
• 2.5” (≈5.9°)
• 3.5” (≈8.3°)
The 3.5” / 8.3° toe-in gave the best ETC profile, reflection control, center-image lock, and overall stage coherence. (Side note: Who knew that ETC was the measure to be used here? I didn’t.)
⸻
Listening Position Micro-Moves
Only after the triangle and toe-in were finalized did I test LP-only shifts:
• –6”
• –4”
• +2”
• +4”
The –4” LP position produced the smoothest and most even bass response of all micro-adjustments.
⸻
Subwoofer Integration
Finally, I optimized the two subs:
• placement
• phase
• gain
• delay
• crossover relationship
The result was tighter, smoother, and more coherent low-frequency integration with cleaner decay and better mid-bass definition.
⸻
Final Setup
• Triangle: +24” forward move from original listening triangle.
• Toe-In: ~8.3°, 0 degrees before.
• LP: –4”
• Mains + Subs: Fully time-aligned and integrated
⸻
End Result
The system now has dramatically smoother bass, better group delay, reduced early reflections, a more stable center image, and the deepest, most coherent soundstage I’ve had in this room.
Using a science based approach with the power of AI to crunch the numbers was invaluable.
Further Work:
I think the sub levels can be tweaked a little. I will also play with using the DARO circuit of the subs to see what that effect is. Chat doesn’t think I need it. We’ll see.
I may also experiment with plugging the ports of the Kharma again and leveraging the subs more into the overall sound.
The sub positions are NOT wife friendly. They would never work in anything but a dedicated room such as I have. Even then, for me, having one sub partially into the middle of the room between me and the equipment rack is weird. It works, but it’s freaking weird.
Lastly, I need to replace the sliders under the Kharmas with the spiked platforms, re-level them and adjust the rake. I may also re-look at the toe-in to adjust the stage to my ‘taste’. I like the more ‘alive’ sound the current toe-in provides but not sure I want so much focus.
Footnote: my room dimensions are not good being a square - 21.1’ X 21.5’ X 9’7”. It does have knee walls and other structure in two corners at the ceiling and a wet bar in another corner so it is not a perfect rectangular box. I sit facing down the long diagonal.
Full Listening Triangle Shift
To keep things simple, I fixed the LP and mains triangle to remove their interaction as a variable at the beginning. The work started by moving the entire listening triangle—both mains and the LP—forward into the room:
• +12”
• +24”
This required creating an accurate grid on the floor using starting ‘triangle’ as the baseline and coming to an understanding with Chat what the reference points were. E.g. where was 0,0, what was the left wall, front wall, right wall and back wall. That took longer than I thought it should.
After measuring the baseline and both moved positions, +24” was clearly superior: smoother bass, cleaner GD, better ETC symmetry, and a deeper, more stable stage. This became the new reference geometry. I accepted Chat’s analysis on this. Embedded in this was it crunching all that data to see the differences AND knowing what is better and what is not. (Side note: I have run REW for years and mostly used the dB v Frequency graphs to guide my tweaks. Mainly because I didn’t really understand what Group Delay or Implulse or ETC were telling me. Chat does understand them and that lead to a better result)
⸻
Toe-In Optimization
With the triangle fixed at +24”, I tested three toe-in offsets: numbing the rear of each speaker outward by these distances and letting Chat calculate the angles, it was simple.
• 1.5” (≈3.6°)
• 2.5” (≈5.9°)
• 3.5” (≈8.3°)
The 3.5” / 8.3° toe-in gave the best ETC profile, reflection control, center-image lock, and overall stage coherence. (Side note: Who knew that ETC was the measure to be used here? I didn’t.)
⸻
Listening Position Micro-Moves
Only after the triangle and toe-in were finalized did I test LP-only shifts:
• –6”
• –4”
• +2”
• +4”
The –4” LP position produced the smoothest and most even bass response of all micro-adjustments.
⸻
Subwoofer Integration
Finally, I optimized the two subs:
• placement
• phase
• gain
• delay
• crossover relationship
The result was tighter, smoother, and more coherent low-frequency integration with cleaner decay and better mid-bass definition.
⸻
Final Setup
• Triangle: +24” forward move from original listening triangle.
• Toe-In: ~8.3°, 0 degrees before.
• LP: –4”
• Mains + Subs: Fully time-aligned and integrated
⸻
End Result
The system now has dramatically smoother bass, better group delay, reduced early reflections, a more stable center image, and the deepest, most coherent soundstage I’ve had in this room.
Using a science based approach with the power of AI to crunch the numbers was invaluable.
Further Work:
I think the sub levels can be tweaked a little. I will also play with using the DARO circuit of the subs to see what that effect is. Chat doesn’t think I need it. We’ll see.
I may also experiment with plugging the ports of the Kharma again and leveraging the subs more into the overall sound.
The sub positions are NOT wife friendly. They would never work in anything but a dedicated room such as I have. Even then, for me, having one sub partially into the middle of the room between me and the equipment rack is weird. It works, but it’s freaking weird.
Lastly, I need to replace the sliders under the Kharmas with the spiked platforms, re-level them and adjust the rake. I may also re-look at the toe-in to adjust the stage to my ‘taste’. I like the more ‘alive’ sound the current toe-in provides but not sure I want so much focus.
Footnote: my room dimensions are not good being a square - 21.1’ X 21.5’ X 9’7”. It does have knee walls and other structure in two corners at the ceiling and a wet bar in another corner so it is not a perfect rectangular box. I sit facing down the long diagonal.
