On the Bench (JEJ)

At 20 Hz and 100 dB, the ULS-15 produced 15.5% THD+N

THD+N vs. Frequency indicates that the ULS-15 stays at 10% THD+N or less from about 14 Hz to 200 Hz.

Frequency response is pretty flat from 20 Hz to 200 Hz.

For the HB-1, THD+N vs. Frequency, distortion stays at about 2% or less from 60 Hz to 20 kHz,

The HB-1's impedance appears to be nominally 8 ohms, with a large peak at 8 kHz. Electrical phase stays within about ± 40⁰.

For the HC-1, 100 Hz at 100 dB and 1 foot produced 4.45% THD+N.

At 1 kHz, 0.52% THD+N. This is excellent performance.

And at 10 kHz, less than 0.3% THD+N.

Room response was reasonably flat from 80 Hz to 20 kHz. Off-axis, there did not appear to be only slight high frequency fall-off.