(I use an Earthworks omni microphone and a Metric Halo ULN-2 FireWire audio interface, in conjunction with SMUGSoftware's Fuzzmeasure 2.0 running on my Apple laptop.) The CR1's treble is smooth and extendedperhaps too extended, considering that this response ideally should slope down a little with increasing frequency, due to the increasing absorptivity of the room's furnishings at high frequencies. I perform this measurement by averaging twenty 1/6-octavesmoothed responses taken for each speaker individually in a rectangular grid measuring 36" by 18" and centered on the positions of my ears in my listening chair. Above that frequency, the tweeter's output continues smoothly until it starts to rise just below the 30kHz limit of this graph.įig.5 TAD Compact Reference CR1, vertical response family at 50", normalized to response on tweeter axis, from back to front: differences in response 15≥° above axis, reference response, differences in response 5≡0° below axis.įig.6 shows how this anechoic behavior translates to the measured spatially averaged response in my listening room. This gives rise to a small peak at 9kHz, followed by an equally small dip in the response at 12kHz. The woofer's behavior above its passband is smooth, and the coaxial drive-unit's response is astonishingly flat, up to the region where the tweeter's output starts to be affected by the fact that it is symmetrically surrounded by the midrange cone. The woofer's output crosses over to the coaxial driver at pretty much the specified 250Hz, with what appear to be 18dB/octave filter slopes. The port's output is a tidy bandpass covering the octave between 30 and 60Hz, with only a slight hint of a resonant peak at 250Hz disturbing its upper-frequency rolloff. The saddle centered on 38Hz in the impedance-magnitude trace suggests that this is the tuning frequency of the port this is confirmed by the minimum-motion notch in the woofer's nearfield output in fig.2 occurring at the same frequency. Below 350Hz, the latter two traces were taken with the microphone in the nearfield above that frequency, the traces show the drive-units' farfield responses on the tweeter axis. Indeed, when I investigated the vibrational behavior of the enclosure's panels with an accelerometer, I found nothing untoward!įig.2 shows the individual responses of the port (red trace), the woofer (green), and the coaxial upper-frequency drive-unit (blue). Other than a small wrinkle at 42kHz, which is presumably the fundamental "oil-can" resonance of the tweeter's beryllium dome, the traces in fig.1 are free from any discontinuities that would imply the existence of resonances of some kind. Fig.1 TAD Compact Reference CR1, electrical impedance (solid) and phase (dashed).
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