Anybody left? Good. Now we can talk about a very special little speaker. In a way, I didn't even want to review the 1S. I mentioned to John Atkinson that I'd heard them at my buddy Ruben's house and enjoyed them immensely, but I'd been using a pair of $13,000 speakers to review an exotic amplifier and had, sad to say, become quite spoiled: bass down to 28Hz, 93dB sensitivity, and some of the most accurate soundstaging I'd ever heard—we're talking about some serious suffering for my art, here.

So when the ProAcs arrived at my house, I thought it unfair: unfair to me (I was gonna miss them big dogs), and unfair to the Response 1S. After all, does anyone remember who played after the Beatles on the Ed Sullivan Show?

Experience 1
On August 25, 2016, John Atkinson, Michael Lavorgna, and I attended an event at Battery Studios, Sony's Manhattan-based music production facility.

The event itself was very personal, as we three were the only non-Sony people present at this particular session. (There were multiple sessions held that day.) We were introduced to Sony's latest hi-res personal audio products—the "Signature Series," which consists of the MDR-Z1R headphones $2199.99), NW-WM1Z ($3199.99) and NW-WM1A Walkman players, and the TA-ZH1ES headphone amplifier ($2199.99).

Most of you have noticed the hyphenated numbers on your address labels, and most of you guessed what they were: Expiration codes. If your label has a 1-12 number on it (or no hyphenated code at all), the next issue of The Stereophile, Issue Number 12 [published in September 1966—Ed.], will be the last one that will arrive on your present subscription.

The ESP-9 is dual-powered: from the AC line, or from the input signal itself, The power supply is rather large and heavy, and appropriate in appearance to the phones. Amplifier connections are via wires with spade lugs attached, and speaker connections are made to the rear of the power supply. A front-panel switch selects speaker or headphone operation, and terminates the amplifier outputs with 10 ohms in the Phones position.

Construction is typically top-of-the-line Koss: Rugged, nicely finished, and apparently very durable, and the phones are easy to handle. (Many headphones are so loosely pivoted on their headbands that they swing into impossible positions whenever you pick them up.)