Big Magnets Make For Better Loudspeakers

Everybody who listens to audio, whether music, podcasts, movies or other media, depends on speakers. From standalone loudspeakers and monitors to headphones and earphones to built-in laptop and cell phone speakers, it’s clear that speakers vary significantly in size. With most speakers being electromagnetic, it begs the question: do bigger magnets make better speakers?

Do bigger magnets make for better speakers? Bigger magnets are required for bigger speakers, but they do not necessarily make them “better.” Larger magnets (and stronger audio signals/voltages) are necessary to move large speaker cones and subwoofers. However, the overall quality of a loudspeaker depends on more than the size of its magnets.

In this article, we’ll discuss the role of magnets in electromagnetic/dynamic loudspeaker drivers, focusing on the factors related to magnet size.

A Primer On Electromagnetic Speakers
Loudspeakers are transducers that convert audio signals (electrical energy) into sound waves (mechanical wave energy). The transducer units are specifically referred to as speaker drivers. The vast majority of these drivers are considered “moving-coil” or “electrodynamic”, working primarily on the principle of electromagnetic induction.

Of course, there are alternative driver designs, which I discuss in my article What Are Speaker Drivers? (How All Driver Types Work) but in this article, we’ll focus on the most prevalent type.

Here is an illustration of the cross-section of a typical speaker driver.

Moving-Coil_Loudspeaker_Driver_Diagram

Moving-Coil_Loudspeaker_Driver_Diagram

The audio signal (AC) passes through the conductive voice coil, and an alternating magnetic field is produced. This magnetic field interacts (causes attraction and repulsion) with the permanent field of the magnetic structure. Suspended within the magnet and attached to the diaphragm, the voice coil pushes in and out, propagating sound waves into the medium as it does so.

So magnets are required for [this popular type of] a speaker to work effectively as a transducer. Now let’s move on to how magnet size affects these speaker drivers as transducers.

Do Bigger Magnets Make For Better Loudspeakers?
Magnets play a significant role in driving loudspeakers. The bigger the magnet, the stronger the potential driving force of the speaker (assuming the magnetic strength of the magnet is constant). Small magnets are for small speakers and produce, by nature, “weaker sound”, while bigger magnets make bigger speakers capable of producing louder sound.

Stronger/bigger magnets will allow for louder sound production. Other factors necessary for louder volume include stronger (more amplified) speaker level audio signals, more heat-resistant voice coils, larger cone/diaphragms, greater room for diaphragm excursion, more optimal speaker enclosure and more. In short, a bigger magnet is one of the factors that allows a loudspeaker to sound louder.

Bigger_Magnets_Make_For_Better_Loudspeakers_large

Bigger_Magnets_Make_For_Better_Loudspeakers_large

But does this constitute the oft subjective term “better”?

Yes, bigger magnets make for better loudspeakers if we’re only concerned with loudness. They make for louder speakers, which are especially important for sound quality in large rooms.

Do Bigger Magnets Make For Better Loudspeakers?
Magnets play a significant role in driving loudspeakers. The bigger the magnet, the stronger the potential driving force of the speaker (assuming the magnetic strength of the magnet is constant). Small magnets are for small speakers and produce, by nature, “weaker sound”, while bigger magnets make bigger speakers capable of producing louder sound.

Stronger/bigger magnets will allow for louder sound production. Other factors necessary for louder volume include stronger (more amplified) speaker level audio signals, more heat-resistant voice coils, larger cone/diaphragms, greater room for diaphragm excursion, more optimal speaker enclosure and more. In short, a bigger magnet is one of the factors that allows a loudspeaker to sound louder.

But does this constitute the oft subjective term “better”?

Yes, bigger magnets make for better loudspeakers if we’re only concerned with loudness. They make for louder speakers, which are especially important for sound quality in large rooms.

Before we move on, it’s important to note that the size of the magnet in any given speaker driver is subject to constraints. The overall size and weight of the drivers are factors to consider. How the magnet will interfere with other audio devices (other drivers, crossovers, amplifiers and other components) must be taken into consideration.

It’s also essential that the magnet’s magnetic field be concentrated in the pocket where the voice coil is suspended. If you questioned the odd shape of the magnet in the illustration I provided earlier, note that the bizarre construction (complete with pole pieces) is to concentrate this magnetic field at the voice coil.

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