LARGE ADVENT SPEAKER MANUAL FULL

In contrast, the 8-ohm setting gave a much more uniform curve, varying between 7 and 13 ohms over the full audio range. There was a broad rise to 14 ohms at 1.5 kHz and a drop to just under 6 ohms at 20 kHz. The shape of the nominally 6-ohm impedance curve was like that of many speakers, with a bass-resonance peak of 23 ohms at 48 Hz and a broad minimum of less than 4.6 ohms between 100 and 200 Hz.

Our tests revealed that the shape of the impedance curve altered dramatically between the two switch settings. The system's sensitivity varied from a high 92 dB to a rather low 86 dB, depending on the setting of the impedance switch. These showed the abrupt drop in output above 1 kHz, with an amplitude of 3 to 6 dB, that appeared in the room curves, but did not match their smoothness at higher frequencies. We also made a number of quasi-anechoic response measurements, using the MLS (maximum-length sequence) program of the Audio Precision test system. The tweeter's horizontal dispersion over a 45-degree angle was good, with on- and off-axis outputs diverging by about 2 dB at 5 kHz, 4.5 dB at 10 kHz, and 16 dB at 20 kHz, which is reasonable for a 1-inch dome tweeter. It showed relatively uniform output (2.5 dB overall variation) from 50 Hz to 1 kHz, where there was an abrupt downward step of 4 dB, and a +/-2-dB variation from 1.2 to 20 kHz. It was nonetheless possible to splice the close-miked and room-response measurements to form a believable composite response curve. Below 60 Hz, its response fell off at 12 dB per octave, to - 5 dB at 40 Hz and - 9 dB at 30 Hz.Д¬lose-miked response measurements of a 10-inch cone are invalid above a few hundred hertz, where its dimensions become comparable to the wavelength of the radiated sound. The close-miked woofer response was flat within 1 dB from 55 to 170 Hz, sloping down gently above that frequency to -3.5 dB at 800 Hz. Our room-response measurements showed relatively flat output from 100 Hz to about 1 kHz and another flat range from 1 to 20 kHz at a 4-dB lower level. The woofer's resonant frequency is given as 50 Hz, +/-5 Hz. The input connectors, spring clips designed to accept only wire ends, are recessed into the rear panel, together with the impedance switch.ДЄdvent's specifications for the Legacy III include a bandwidth of 40 Hz to 23 kHz, sensitivity (6-ohm setting) of 90 dB sound-pressure level (SPL) at 1 meter with a 2.83-volt input, and a crossover frequency of 2.5 kHz. The woofer, operating in a sealed enclosure, is at the midpoint of the front grille, with the tweeter above it, near the top of the front panel. The front is covered by a removable black cloth grille.

The Legacy III's cabinet is made of 3/4-inch particle board covered with black textured vinyl, with a solid pecan top plate and base trim. If two or more pairs of speakers are driven in parallel, as they might be in a multiroom installation, for example, the 8-ohm setting lightens the load on the amplifier. The manufacturer recommends using the 6-ohm setting when the amplifier is driving a single pair of speakers, since that will deliver the system's maximum sensitivity (efficiency). The woofer is unusual in having a dual voice coil that enables the system impedance to be set at either 6 or 8 ohms by means of a toggle switch on the back of the cabinet near the input terminals. The Advent Legacy III is a two-way floor-standing speaker system using a 10-inch woofer and a 1-inch soft-dome tweeter with magnetic-fluid damping.

Large advent speaker manual