Speaker Property Dependency on Temperature
Temperature contribution to the speaker system is not negligible.

Environment including temperature, humidity, air pressure, aging and other factors impact the properties of the speaker system. Most are negligible in normal living environment. The magnet strength is influenced by many environmental factors. But, most sensitive components are the surround and the dumper. Especially the surround is the most delicate part in the speaker construction. This experiment is to measure the speaker and sound properties affected by cold or warm environment.

Here, temperature contribution is altered for various speaker drivers in this experiment.
The drivers used are Companies M, P, D, A, T, and J made from 13cm diameter to 38cm.

Temperature condition (Low: Approx. 15C High: Approx. 25C)
Red line shows in case temp is 15C, and black line is 25C in all graphs below.
Please note that the temperature is approximate number.

Aug. 2012, MJ Magazine

Photo of the surround Impedance Shift of the Driver
(Black:15C Red:25C)
Impedance shift in the enclosure
(Black:15C Red:25C)
Company "M" made
16cm diameter driver
Surround material: Artificial lather
Formation: Round
Not available
Company "P" made
16cm diameter driver
Surround material: Cloth
Formation: Round
Not available
Company "D" made
13cm diameter driver
Surround material: Rubber
Formation: Round
Impedance with the enclosure


Company "A" made
13cm diameter driver
Surround material: Rubber
Formation: Gathered
Impedance with the enclosure

Company "T" made
38cm diameter driver
Surround material: Cloth with treatment
Formation: Waved
Impedance with the enclosure
Not available
Company "J" made
38cm diameter driver
Surround material: Artificial Cloth
Formation: Round
Not available
As a bottom line,
the System frequency response is influenced as shown below.
Driver D Driver A Driver T
Frequency response when Driver D is mounted on the enclosure where D is 17cm diameter as described above.
60-100Hz band is uplifted with Max. 2dB at higher temp. This is not negligible value from the point of hearing the music.
Frequency response when Driver A is mounted on the enclosure where A is 17cm diameter as described above.40-90Hz band is uplifted with Max. 4dB at higher temp. This is large value from the point of hearing the music.
Frequency response when Driver T is mounted on the enclosure where T is 38cm diameter as described above.
Surprisingly enough, there is no uplift is recognized in the low frequency band. This may be that the influence of the surround is relatively small because of heavy diaphragm.
Above experiments gives us that we listen deferent sound in each season though it depends upon each environment. This also means that the sound show difference between the time "soon after we powered on the amplifiers" and the time "after 15-30 min warmed up" especially in the low frequency domain. So, we have to consider about this effect.


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