Myth-Busting Hi-Fi: Tweeter Tricks and Off-Axis Myths

[Bob Rapoport]

The Myth:
Some manufacturers recommend turning speakers inward or outward to “smooth out” the treble response. The story goes that off-axis listening gives you a more natural sound.


The Truth:
Physics says otherwise. As frequency rises, wavelengths shorten. Bass spreads like a balloon, but treble beams forward like a flashlight. The only way to hear the full frequency response — especially in the high frequencies — is to listen on-axis.


When a manufacturer tells you to toe-in or toe-out unnaturally, it’s often to mask flaws such as tweeter ringing or resonances at the top end. In other words, it’s a design compromise, not a performance feature.


Why It Matters:
Stereo recordings are mixed to create a 3D soundstage, with instruments and voices placed precisely across the stage. If you’re listening off-axis, you’re throwing away localization cues and detail. On-axis, with careful setup, you hear what the artist and engineer intended.


The Takeaway:
Don’t let myths or marketing gimmicks steer you off course. Start with on-axis listening — the physics are on your side.

 

[w_sizer]

It depends…If you’re listening to speakers with an elevated in-room treble response, you can reduce listening fatigue by angling them slightly off-axis from the MLP. Moreover, some speakers (eg, ones with concentric drivers) are actually designed to be angled out by 10-15 degrees). See attached YT review of the KEF R3 Meta by Erin’s Audio Corner.

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[Bob Rapoport]

It depends…If you’re listening to speakers with an elevated in-room treble response, you can reduce listening fatigue by angling them slightly off-axis from the MLP. Moreover, some speakers (eg, ones with concentric drivers) are actually designed to be angled out by 10-15 degrees). See attached YT review of the KEF R3 Meta by Erin’s Audio Corner.

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For more detailed information, see our cookies page.

Accept third party cookies

"Some kind of diffraction element if you don't toe the speaker out 10-15 degrees" sounds to me like a design flaw being covered up. This means the highest frequencies are aimed away from the listener and end up as reflections that can interfere with the coherent soundwaves, smearing the stereo image. The ASR measured frequency response graph shows the tweeter output in red with a significant peak at 10 KHz with a rapid roll-off beyond. This may account for what the reviewer heard.

 

[JStewart]

This means the highest frequencies are aimed away from the listener and end up as reflections that can interfere with the coherent soundwaves, smearing the stereo image.

Likely not in this case due to the directivity, which is narrow and very even compared to most speakers and I think that was the point.

The ASR measured frequency response graph shows the tweeter output in red with a significant peak at 10 KHz with a rapid roll-off beyond. This may account for what the reviewer heard.

Amir on ASR measured the previous version, not the meta version.

I’d like think the correct approach for the average home listener is to first set speakers up on axis and then experiment with toe-in or out to suit. Folks have different tastes and different rooms, not to mention wildly different speakers.

 

[Bob Rapoport]

Likely not in this case due to the directivity, which is narrow and very even compared to most speakers and I think that was the point.



Amir on ASR measured the previous version, not the meta version.

I’d like think the correct approach for the average home listener is to first set speakers up on axis and then experiment with toe-in or out to suit. Folks have different tastes and different rooms, not to mention wildly different speakers.

The response chart above says its testing the Meta version. The top octave of audible sound in humans is 10KHz to 20KHz;. Most of it is like a flashlight beam 6: wide. The very highest frequencies are like a laser beam, less than an inch wide. The higher the frequency, the narrower the wavelength. Being off-axis just a little bit means that beam of high frequencies can miss our ears and hit the wall behind us. Its the difference between hearing the localization cues in the music or not. We humans are quite good at that. Most mammals have even better hearing than we do.

The human auditory system evolved over millennia for survival, hearing the sound of a twig snapping at 50 yards away and knowing within inches the location of the twig was the difference between life and death. This ability is put to use by audiophiles who value pin-point precision imaging. I think the Uni-Q technology puts the tweeter where it belongs, as a point source, it has a better chance of delivering pin-point imaging than most speakers. The industrial design and craftsmanship are state-of-the-art.

 

[JStewart]

The response chart above says its testing the Meta version.

Yes, it does. Not my point though.

Most of it is like a flashlight beam 6: wide. The very highest frequencies are like a laser beam, less than an inch wide. The higher the frequency, the narrower the wavelength. Being off-axis just a little bit means that beam of high frequencies can miss our ears and hit the wall behind us.

I believe this is conflating wave length and beam width. It’s either that or I am completely missing the point on charts such as this:

I read this as for a good portion of the upper HF range above 10k the frequency is not falling off between +20° and -20°. If correct, the width of the beam is greater than 7 ft at a distance of 10ft. Is this not correct?

 

[ddude003]

@JStewart had said: "I’d like think the correct approach for the average home listener is to first set speakers up on axis and then experiment with toe-in or out to suit. Folks have different tastes and different rooms, not to mention wildly different speakers."

Not to mention ears and brain... Although I may not be the "average home listener", I like my Martin Logan ESLs pointed to cross about 12 inches behind my head (toe-out from on-axis)... And that is with precise room location positioning, time aligning and DRC FIR EQing over a B&H type house curve...

Another thing to consider might be the Fletcher Munson effect and how do you effectively A/B variations of toe...