Construction The T 400 gains an acoustic advantage through its solid build and a strutted MDF fibreboard enclosure. Its slender format allows it to blend discreetly into any room, despite a substantial 23 litre volume.
Tweeter When it comes to frequencies above 3000 hertz, the T 400 relies on a larger than average, 28 mm fabric dome tweeter with a neodym magnet system. The tweeter is recessed in relation to the mid- and low-range drivers to guarantee the perfect timing of impulse and speech rendering.
Waveguide A special "Waveguide" mold surrounding the tweeter guarantees homogenous, even distribution of sound. This significantly reduces any burden on the driver's hub. Any echo from the room's walls is kept at an absolute minimum.
Mid-range driver The T 400's 165 mm driver is optimised for mid-range sound using the Klippel technique and features a light paper-sandwich cone membrane in a solid metal basket constructed to accommodate currents. It also uses a dust cover dome made of light mesh, and its 32 mm oscillating coil in a linear magnet system is housed in its own enclosure to eliminate influence from other frequency ranges.
Bass The T 400 features a deep range driver optimized for bass using a 130 mm Kevlar mesh membrane, a long-throw crimp and a resilient 32 mm oscillating coil.
Precision 
The T 400 is designed to render bass for analytic listening. Instead of sound swamped with superficially-impressive levels of bass, it delivers individual bass parts which are consistently clear and differentiated. A meticulously tuned bass reflex construction with a large-format reflex pipe contributes to this significantly.
Crossover An elaborate crossover , distortion-resistant components (such as film capacitors for the tweeter) is split between bass and mid-to-high ranges. It ensures individual frequency blocks are distributed to the appropriate drivers and further sets the T 400 apart from other stereo speakers in its price range.
Connection The T 400 features a doubly structured connector panel with stable, gold-plated screw terminals. It enables ongoing improvements to sound quality through bi-amping, for example.
Positioning Thanks to the T 400's neutral tuning, these speakers can be freely placed near walls or throughout a room. They include rubber feet and come ready for use with Teufel spikes.
Combinations With its 85db/m degree of efficiency, the T 400 can be used with amplifiers starting at 50 watts per channel. However, the speakers benefit from any increase in amplifier quality. A maximum capacity of 180 watts ensures significant "upwards" leeway.
Room space The T 400 is an ideal listening companion for distances up to 4.8 metres, as are commonly found in rooms up to 35 sqm.
