Test Report: Thiel Audio SCS4T Tower Speakers Page 3

Frequency response (at 2 meters): 51 Hz to 20 kHz ±4.2 dB

Sensitivity (SPL at 1 meter with 2.8 volts of pink-noise input): 86 dB

Impedance (minimum/nominal): 2.8/4 ohms

Bass output (CEA-2010 standard)

  • Ultra-low bass (20-31.5 Hz): NA
  • Low bass (40-63 Hz): 93.1 dB

Measurements of the SCS4T speakers were made at 2 meters, far enough to ensure that full effects of cabinet diffraction and front-panel reflections were included. The metal grille was removed. The SCS4T was measured standing on the ground, the way it will always be used, with an on-axis measurement taken at 3 meters to capture the effect of floor bounce. The curve in the graph shows an averaged response from 0° to 30°, smoothed to 1/12th of an octave. The woofer and ports were close-miked, scaled, and summed, then their combined responses were spliced to the averaged quasi-anechoic response to produce the curve you see here. The response is normalized to 0 dB at 1 kHz.

The averaged frequency-response measurement of the SCS4T is okay, although not especially even. The overall balance has a downward tilt (i.e., more bass than treble), and there are several dips and peaks in the response. However, the off-axis response is very consistent up to about 10 kHz; there’s just a mild treble rolloff as you move to 45° off-axis. Above 10 kHz, the response changes unpredictably, possibly a result of the tweeter being positioned inside the woofer cone. There seems to be a mild floor dip at about 450 Hz.

Sensitivity measures 86 dB, just a bit below average and reason enough to recommend an amp of at least 50 watts per channel. The impedance is fairly low, but the impedance phase curve is flatter than average — something that has been the case with Thiels for as long as I can remember. Impedance drops to a low of 2.8 ohms at 9.9 kHz and averages 4 ohms. Maximum impedance phase shift is just –32° at 114 Hz. Regardless, don’t cheap out on your amp with this speaker.

Bass output is pretty good for a 6.5-inch woofer in a relatively small cabinet. There’s nothing measurable below 40 Hz, but output from 40 to 63 Hz averages a fairly strong 93.1 dB. You won’t get deep bass, but the speaker definitely won’t sound thin without a subwoofer.