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The plot above is from Celestion. It appears the cone breakup starts at about 2.5kHz. After that, there’s a peak at 4kHz beyond which it dies off.
Fig 1 is my measurement of the Celestion TF0818 in a 24 liters ported box. The bandwidth looks similar to the manufacturer.
Fig 2 is the Waterfall plot. It recorded a strong artifact at 4kHz, exactly where the peak is..
The Toneburst plot (Fig 3) recorded a bunch of light blue slices at 4kHz. These are the artifacts represented in cycles (z- axis) instead of time.
The Spectrogram in Fig 4 is a 2D representation of the Waterfall. In this plot, the Y-axis is in time (msec). There are some streaks from 2kHz onwards but they dissipate by 2msec, indicating the artifacts are inaudible.
Interestingly, the 3rd harmonic dominates the 2nd in the TF0818 (Fig 5). Fortunately, my crossover is at 2kHz so the odd harmonics will not interfere with the sound. Summary Compared to the Eminence Beta 8A, I expect a clearer vocal reproduction from this Celestion TF0818. If I’m right, the TF0818 would make a splendid mid/high 2-way. Unless otherwise stated, all measurements were made in Full Space (4 pi) with the mic at 36 ins, tweeter axis. Impulse Window=5ms. No smoothing applied. |
November 12, 2025PRO DRIVERS
