@ledoux1238 

Here you go.  I'll make two posts with different results as you say your between speaker distance is 260cm. I would think the calculation will be the most accurate if the between speaker distance was on-center on the panel face.  I'm guessing(?) your 260cm refers to the distance between the inside edges of the speaker. With the speakers(including trim) being about 13 inches (33cm) wide, the second post I'll make adds 33cm to your 260cm  to arrive at what I think may be your on-center distance between speakers. 

OK..this response is for 260cm on-center between speakers. 

ChatGPT question on listening triangle of 260cm x 300cm:

ok, i have a different room where I need toe-in angles. The distance between the speakers is 260cm (on center). The distance from the speaker face to the listener is 300cm. Please give the result in the same format as your last response above. Also please give the resulting toe-in angles in degrees and radians. 

Answer:

Perfect—same method, new room. Let’s run it cleanly.

---

🧠 Your new geometry

• Speaker spacing = 260 cm

• Listening distance = 300 cm

• Half-spacing = 130 cm

---

📐 1. Toe-in for axes crossing at your head (on-axis)

---

🎯 RESULT

👉 23.4° (0.408 rad) toe-in = speakers aimed directly at your head

This is your reference point.

---

🧠 Context (same physics as before)

• Your spacing vs distance is wider relative to listening distance than your previous room

• So:

  • Toe-in angle is smaller

  • But lobe sensitivity (~7° at 10 kHz) still applies

---

🔵 2. Axes crossing behind your head

Reduce toe-in slightly:

Practical range:

👉 20°–22°
👉 0.35–0.38 rad

---

What happens here

• Slightly off-axis to midrange

• Tweeter dominates a bit more

Result:

• smoother

• less comb filtering

• but:

  • softer center image

  • reduced vocal density

---

🟢 3. Axes crossing in front of your head

Increase toe-in beyond 23.4°:

Optimal range:

👉 25°–28°
👉 0.44–0.49 rad

---

Why this works

• Moves you out of 10 kHz null zones (~±7° spacing)

• Better aligns:

  • midrange beam

  • interference main lobe

---

🎯 Your exact “target zone”

👉 Best starting point: ~26° toe-in
👉 ≈ 0.45 rad

---

🎧 Fine-tuning window

• Adjust in ~1° increments

• Sweet spot likely:

👉 25°–27°
👉 0.44–0.47 rad

---

🧠 What you’ll hear when it’s right

• Dense, locked center image

• Smooth but present treble

• No “hole” in upper mids

• Speaker disappears

---

📊 Summary

 

---

🧾 Final answer

👉 Calculated toe-in (on-axis): 23.4° (0.408 rad)
👉 Optimal real-world toe-in: ~26° (≈0.45 rad)

---

 

OK..this is for 293cm between speakers on-center

ChatGPT question on 293 x 300 listener triangle:

ok, one more room where I need toe-in angles. The distance between the speakers is 293cm (on center). The distance from the speaker face to the listener is 300cm. Please give the result in the same format as your last response above. Also please give the resulting toe-in angles in degrees and radians. 

Answer:

Perfect—same process again, now with your wider spacing.

---

🧠 Your new geometry

• Speaker spacing = 293 cm

• Listening distance = 300 cm

• Half-spacing = 146.5 cm

---

📐 1. Toe-in for axes crossing at your head (on-axis)

---

🎯 RESULT

👉 26.0° (0.454 rad) toe-in = speakers aimed directly at your head

This is your reference point.

---

🧠 Context (important subtle shift)

Compared to your previous room:

• Speakers are wider relative to distance

• So:

  • Slightly more toe-in required

  • Greater sensitivity to small angle changes

👉 You’re getting closer to a wide triangle, which makes lobe alignment more critical.

---

🔵 2. Axes crossing behind your head

Reduce toe-in slightly:

Practical range:

👉 23°–25°
👉 0.40–0.44 rad

---

What happens here

• You move off the midrange beam

• Tweeter dominates slightly

Result:

• smoother

• less comb filtering

• but:

  • softer imaging

  • reduced presence energy

---

🟢 3. Axes crossing in front of your head

Increase toe-in beyond 26.0°:

Optimal range:

👉 27.5°–31°
👉 0.48–0.54 rad

---

Why this works

• Your wider spacing increases lobe steering sensitivity

• Extra toe-in:

  • pushes nulls outward

  • aligns main summation lobe with your ears

---

🎯 Your exact “target zone”

👉 Best starting point: ~28.5° toe-in
👉 ≈ 0.50 rad

---

🎧 Fine-tuning window

• Adjust in ~1° increments

👉 Likely sweet spot:

• 27.5°–29.5°

• 0.48–0.52 rad

---

🧠 What you’ll hear when it’s right

• Center image becomes very dense and stable

• Treble integrates cleanly (no edge, no dip)

• Strong sense of depth

• Speaker disappears

---

📊 Summary

 

---

🧾 Final answer

👉 Calculated toe-in (on-axis): 26.0° (0.454 rad)
👉 Optimal real-world toe-in: ~28.5° (≈0.50 rad)

---

 

...and for an update on my setup/toe-in tuning:

A few days ago, after swapping the left for right and right for left speakers to get the midrange panels on the inside, I played with toe-in and arrived at 21 degrees of toe-in as "good".  This was based on ears & listening alone. Sounded pretty good and was an improvement over the toe in I 'd set previously, which, guessing only, was probably in the 15ish degrees area. 

As a side-note..GPT states the speakers "disappear" when you have things set up right..well..I've had 9 months of "setting them up wrong" and they've always disappeared and sounded great, though some seat-of-the-pants setups were better than others. 

After the ChatGPT adventure yesterday and GPT suggesting my optimal toe-in for an axis crossover slightly behind my head was 24-26 degrees, I increased the toe in from 21 to 23 degrees.  It was an improvement, though things are getting pretty marginal with trying to distinguish improvements. 

Being a little anal..and that 24-26 degree "optimum" hanging out there like a big matzah ball..I made a further toe in adjustment to 24.5 degrees. I think I'm done & GPT may have gotten it right.  This is the best setup I've heard..and I've heard at least 6-8 with these speakers..and honestly, they all sounded great (except for direct axis on head..that was a little intense). 

@nogaps First of all, thank you for the measurements.
 

I did some experimenting last night. The distance I gave, 260 cm, was measured from center of speakers. But because they were only 20cm from side wall and with these toe-in angles, the speakers had to be moved closer together so as not to hit the side walls. They are now spaced around 230cm center to center instead, so I am using the toe-in angles you supplied as references to extrapolate. I am not at the suggested optimal yet, but what I am hearing is a much more energized soundstage and more center filled. It’s like  moving from balcony to the front row. 
 

With my previous straight firing setup, the speakers ‘disappeared’ pretty well, so I agree with you. The LFT-8s are good at disappearing with many setups. The big difference for me is the soundstage. Previously it occurred entirely behind the speakers with a wide spread. With good recordings, it would spread beyond the speakers. The toe-in setup moved the entire soundstage to the face of the speakers. I was listening to digital last night, the ‘lesser’ format, so not quite as wide as vinyl. But the entire frequency response is much more balanced, down to the bass. 
 

I had experimented with toe-ins when the speakers were in their 8b version. But I never remember hearing such coherence in the soundstage. Then again, I had never had the midrange on the inside, so that may be the crux of the matter. It’s interesting that Bruce has always been quite agnostic about this, recommending that I try both. 

 

In any case, a very positive start on this new speaker placement journey, quite exciting really! I have not been so hyped since first receiving the speaker five years ago. I’ll be fine tuning and trying to dial it in this week. 

 

It’s such a shame that so few people venture away from the far-better known Magnepans, ignoring the Eminent Technology LFT-8b/c (your choice), the best value(s) in a dipole/planar loudspeaker for over 35 years! While both are planar-magnetic designs, they sound quite different from one another. While I’m sure I could be happy with a pair of MG3.7i’s (with the Danny Richie-designed GR Research mod), I couldn’t with a pair of 1.7i’s, the LFT-8b’s competition.