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Udo Wohlgemuth's goal was to "again design a great speaker with marvellous tops and with an extremely three-dimensional and tight bass."

Frequency response

The frequency responses of the individual drivers as well as the total frequency response, with and without subwoofer, are recorded below. The slight dip at 3.5 kHz is negligible since the human ear hardly notices a decline in the response, while a rise is regarded as irritating, but doesn't exist here. The purple curve is a near field distribution measurement, adjusted by the volume, so that it may be complemented - at a two-dimensional evaluation - by the radiation of the bass reflex tube (refer to Joseph D'Appolito: Lautsprecher-Messtechnik, ISBN 3-8957-6090-0, 419 pages).
Picture 1: frequency response of Stra To with and without subwoofer, as well as frequency responses of the individual drivers.

Frequency response under several angles

The frequency responses under several angles (0, 10, 20, 30 degrees etc.) are shown below. Below 30 - that's where most people are listening - the dip in frequency is hardly noticeable. The total frequency curve is quite flat.
Frequenzgang unter Winkel
Picture 2:frequency response under several angles


The diagram below shows the impedance response. The assumption, that the impedance of the bass reflex tube has to be same as the one of the bass driver within the cabinet, is a cock-and-bull story from the time when there were no Thiele Small parameters. Today the frequency response is the most important criterion. The rise in impedance above 1.7 kHz (red curve) can be flattened by an impedance correction (blue curve). The impedance correction consists of three components.
Picture 3: impedance response of the satellite

Distortion factor

The distortion factor of the speaker is within the important frequency range (i.e. above 200 Hz) below 1% (quotient of the useful signal with 90 dB and distorted signals). That is a very good result.
Picture 4: non-linear distortion (distortion factor).

Waterfall spectrum / decay spectrum

The decay spectrum is even. There is no resonance noticeable. A resonance causes irritating distortion.
Picture 5: Decay spectrum / waterfall spectrum

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