Electrostatic tweeters have maintained unbroken popularity for several decades. The large but light diaphragm, which radiates sound to both sides of the diaphragm, generates light, overall unfussy sound with excellent spatial qualities that is not attributable to a particular source and fills the room evenly with music. This type of speaker is generally extremely complex to manufacture and, as a result, not easily affordable. However, it is possible to create a sound experience very similar to this using conventional cone speakers mounted in an open baffle.
For the NoBox 170, four high-grade WS 17 E - 4 Ohm bass drivers with paper diaphragms were selected that are optimised for free-air use. Due to the fact that they have no cabinet, they produce wonderfully clean low-frequency bass. Also, thanks to the dipole principle, they generate fewer standing waves, which means the bass tends to fade more quickly, so it can never become fuzzy and does not drone. On top of this, there is the WS 13 E - 8 Ohm mid-range driver that also features a paper diaphragm and a high quality standard, making it ideal for free air use. In order to maintain the same standard of visual appearance, acoustic quality (and to stay in a moderate price range) paper diaphragms have also been used for the tweeters. The TW 6 NG - 8 Ohm provides a fitting finish with finely detailed, clearly defined high-range frequencies to ensure the soundproduced by the NoBox 170 is a harmonious whole. Since the tweeter is the only driver that is closed at the rear, a second driver is mounted back-to-back to emulate the dipole principle right through to the higher range. The level can be regulated and even switched off via a potentiometer. In this way, the tonal balance and the depth of the stage can easily be adapted to suit the actual listening environment and personal preferences. It is important to place the NoBox 170 at a sufficient distance from the rear wall to allow the considerable low-frequency bass to develop and so as not to restrict the depth of the stage layout.
Once correctly positioned and set up, the sound experience is fascinating: the NoBox 170 reproduces voices and instruments in the centre of the room with an airy lightness without artificially inflating them or shifting them laterally or in terms of depth. When seated in the middle of the listening space, the listener is treated to excellent clarity, but even in the seats right at the fringes of the space, the overall sound quality does not break up but remains faithful to its position and lively character in the room. Listening pleasure with the NoBox 170 is unusually stressless, the tonal balance and large-format diaphragm ensure superior performance down into the deepest bass regions of a standard one would not expect from such a small-sized speaker.
Anyone looking for a speaker arrangement with plenty of diaphragm area that can import a special atmosphere into the sitting room as a full-rangedipole, close to the results produced by large electrostatic speakers, should look at - and listen to - the NoBox 170 very closely.
Component parts list for 1 box
The kit includes all the components listed here but not the cabinet.