Fig.3 Elac Debut B6, anechoic response on tweeter axis at 50", averaged across 30 horizontal window and corrected for microphone response, with nearfield responses of woofer (blue), port (red), and their complex sum (black), respectively plotted below 300Hz, 850Hz, and 300Hz.
Higher in frequency in fig.3, the Elac's farfield response, averaged across a 30 horizontal window centered on the tweeter axis, is extraordinarily flat from the upper bass through to the high treble. This graph was taken without the skeletal, plastic-framed grille. With the grille, the speaker's output in the presence region dropped by more than 2dB. I took the opportunity to measure both samples; fig.4 reveals that they match superbly well for such an inexpensive speaker. (This graph was taken in-room, hence the uneven response below 1kHz.)
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Elac Debut B6 loudspeaker Measurements | Stereophile.com