We also measured the 805 D4. We find the D4 version to be without a doubt less bright than the D3 version. It also comes across as a bit rounder and more pleasant in the midrange. Is that visible in the measurements?
Partly. The distortion of the D4 is more uniform than the D3. Now, we never measured the 805 D3 on the ‘new’ set-up, but we did measure the 803 D3. and if we look at the tweeter characteristic curve, it rises in distortion, where the D4 stays the same. Something is gone there. Also, the 2nd harmonic is slightly more dominant in the D4 than in the D3. That also affects the sound. All in all, especially the distortion is lower and more even in the D4.
The tuning is the same. We see the well-known Bowers Bump that pushes towards 5dB from 4 kHz to 12 kHz. The mid is also pushed a bit, so between 1500 Hz and 6000 Hz there is a lift of 7dB! That’s just a lot.
We did most of these measurements at 1 meter with a window of 3ms; so we are not measuring space in this measurement. We also measured at 2 meters and off-axis.
If we purely look at the technical side, we see that Bowers & Wilkins really knows what it does: the distortion is very low. From 65 Hz, the 805 dips below 1% distortion. And it stays there. The bulk of the spectrum is below 0.3 to 0.18% distortion. This can safely be called clean and is simply good even in this class. The evenness of the distortion is particularly striking. In short: it is a choice of Bowers & Wilkins to tune like this.