..and it’s lead me to a final question..how much toe in do I need, given my setup.
ChatGPT question about toe in actual angle:
Calculate my exact toe-in angle in degrees based on my room and listening distance. My speakers are 117 inches (on-center) apart and 112 inches (on-center) from my head at the listening position.
answer:
Perfect—now we can do this precisely for your Eminent Technology LFT-8b.
🧠 Your geometry
-
Speaker spacing = 117 in
-
Listening distance = 112 in
-
Half-spacing = 58.5 in
This is a classic isosceles triangle.
📐 1. Toe-in for axes crossing at your head (on-axis)
🎯 RESULT
👉 27.5° toe-in = speakers aimed directly at your head
This is your reference point.
🧠 Now we place this in context of lobes
From earlier:
-
First null spacing ≈ ±7° at 10 kHz
So small changes from 27.5° matter a lot.
🔵 2. Axes crossing behind your head
To do this:
-
Reduce toe-in slightly
Practical range:
👉 24°–26°
What happens here
-
You move off the central lobe
-
Midrange (beaming) drops slightly
-
Tweeter still strong
Result:
-
smoother
-
less comb filtering
-
but:
-
slightly softer imaging
-
reduced vocal density
-
🟢 3. Axes crossing in front of your head
To do this:
-
Increase toe-in beyond 27.5°
Optimal range (based on your lobe spacing):
👉 29°–33°
Why this range works
-
+2° to +5° = enough to:
-
shift 10 kHz nulls away from your ears
-
keep you inside a main summation lobe
-
🎯 Your exact “target zone”
Given your geometry and the ~7° lobe spacing:
👉 Best starting point: ~30° toe-in
🎧 Fine-tuning window
Once you set ~30°:
-
Adjust in 1° increments
-
Your sweet spot will be narrow:
👉 Likely between:
29° and 31°
🧠 What you’ll hear when you hit it
-
Center image becomes dense and locked
-
Treble stops sounding “separate”
-
No edge / no dip in presence region
-
Speaker “disappears”
📊 Summary
| Toe-in | Geometry | Result |
|---|---|---|
| ~24–26° | Behind head | Smooth but softer |
| 27.5° | At head | Precise but can be edgy |
| 29–31° | In front | ✅ Best balance |
| 32°+ | Far in front | Narrow / bright |
🧾 Final answer
👉 Your calculated toe-in: 27.5° (on-axis reference)
👉 Your optimal real-world toe-in: ~30°
If you want, I can translate that into something practical like:
-
“inches of front edge movement”
-
or laser pointer alignment method
so you can set it precisely without measuring angles.
_________________________
Back to my setup. By ear alone, I have a current toe-in angle of 21 degrees. Chat suggests a mild behind the head optimum would be in the 24-26 degree range. Looks like I have more experimenting to do. I may be close to one of the other lobes. We’ll see.