What is the upper limit for high-frequency sound reproduction? While super tweeters can now produce frequencies up to 40 kHz, the average human ear typically only detects sounds up to 20 kHz. This raises the question: Are super tweeters just a marketing ploy, or do they truly offer real advantages?

Aperion Audio Super Tweeter Speakers

01 | Introduction

When examining the specifications for Aperion Audio’s super tweeter speakers, one figure stands out: 40kHz. These super tweeters, which employ planar ribbon, aluminum ribbon, or AMT (Air Motion Transformer) technology, feature an upper frequency limit that significantly surpasses the 20kHz threshold typically recognized as the limit of human hearing.

This raises an interesting question: If the human ear can’t detect sounds beyond 20kHz, why does Aperion Audio extend the high-frequency range to 40kHz or even beyond? Is this a legitimate breakthrough in audio engineering, or could it simply be a clever marketing strategy?

The answer to this question is more intricate than one might expect.

02 | Is it true that the human ear can only hear up to 20 kHz?

The commonly accepted hearing range is: 20 Hz – 20 kHz

However, this applies only to: An ideal situation involving young individuals with perfect hearing abilities.

In reality:

Age Audible high frequencies
10 20 khz
20 18-20 kHz
30 16-18 kHz
40 14-16 kHz
50 12-15 kHz
>60 10-12 kHz

Many experienced audiophiles find, after undergoing hearing tests, that they can no longer perceive frequencies above 15 kHz. This leads to an even more pressing question:

If many people can’t hear sounds above 15 kHz, why are there super tweeters that reach up to 40 kHz?

Aperion_Super_Tweeters

03 | The Upper Frequency Limit is Not About Hearing 40kHz

This is a common misconception.

When Aperion engineers design a super tweeter with a 40kHz upper limit, the intent isn’t for users to actually hear 40kHz.

Instead, the goal is to achieve outstanding performance within the audible 20kHz range.

Let’s consider a simple example: Imagine two tweeters

Tweeter A has an operating limit of 20kHz,

Tweeter B has a limit of 40kHz.

If both are tasked with playing a 15kHz tone:

Tweeter A is working near its limit:

● Its diaphragm starts to encounter breakup (irregular vibration).

● Phase distortion builds up.

● Distortion levels increase.

Meanwhile, Tweeter B:

is only using half of its capacity.

As a result, it enjoys:

● More linear performance

● Lower distortion

● Improved transient response

It’s akin to comparing two engines—one with a top speed of 200 km/h, and the other boasting a top speed of 400 km/h.

When both are driven at 100 km/h, the latter operates with much more ease and composure.

04 | High-Frequency Extension and Diaphragm Break-up Distortion

One of the biggest challenges faced by a tweeter is break-up, often referred to as "split vibration."

In an ideal situation, the entire diaphragm would vibrate uniformly.

However, the reality is different: as the frequency increases, various sections of the diaphragm start to vibrate independently.