S220

Distortion tests were measured at 12". The room response was at 1 meter.

At 20 Hz, THD+N was an unacceptable 30.5%. You really need a larger driver (e.g., 18") or long throw driver, a more powerful amplifier, and a larger enclosure to get a good output at this low frequency.

Maximum output at a combination of 20 Hz, 31.5 Hz, and 50 Hz was 112 dB (1 meter).

At 25 Hz, THD+N approached an acceptable level (10% is considered acceptable by some people in the business).

At 31.5 Hz, we finally reach the standard acceptable level of THD. My own preference is to not have more than 3%, but that's just me.

At 40 Hz, 4% distortion.

And at 50 Hz, 2%. Overall, fair performance, but not great. The output profile will improve if you use two of these subs. Dr. George Ruben - one of my colleagues at Dartmouth University - uses one Final Sound subwoofer for each of the five channels (he has 800i ESLs all the way around).

The room response with all EQ turned down rolled off below 40 Hz. With the Bass EQ turned all the way up, performance improved significantly.

Conclusions

The Final Sound 1000i electrostatic speakers are truly delightful. I loved the transparency, the clarity, the natural timbre, and the smoothness of the sound. They require a good amplifier, but that is standard for ESLs. I would suggest getting more than one of the subwoofers, or as an alternative, one subwoofer with a larger driver and more amplifier power.
 

- John E. Johnson, Jr. -