One reason for choosing the DD+ 10 was its DSP-based calibration program. However, since this relies on signals from an included CD and a CD player hasn't been in my system for years, Maximilian Merk, the Audio Reference employee responsible for my region, installed and adjusted the subwoofers according to his experience. Each of the two Velodynes was connected via an XLR cable to the Audio Exclusive R7 preamplifier, which fortunately has two balanced outputs of equal value, so that an unaffected signal was still available for the Einstein power amplifier. The result was quite positive, but with such sensitive settings as those of the phase in 15-degree steps, I didn't want to rely solely on my ears. Later, I retrieved a 20+ year old NAD CD player from the basement, which immediately played the CD without any problems despite the long period of inactivity. In the meantime, I had also installed Velodyne's setup program on my Windows laptop. There is no version for Mac, but from the middle of the year firmware and software should be available that will enable setup of Velodyne's DD+ models via smartphone.

With the help of sweep tones on the CD, the supplied measuring microphone, and a Windows computer, I then allowed the two subwoofers to calibrate themselves, one after the other, using the Auto-EQ^Plus program. Since my listening position is not quite on the symmetry axis of the room, because one should still be able to hear well from an armchair next to the listening position - after all, enjoying music is not a hobby only for autistic people - this resulted in two different volume settings: the woofer on the left indicated "0", the one on the right "1". And that almost borders on refusal to work. Unfortunately, the automatic calibration does not work with my speakers, which radiate the low frequencies to the front and back, and with my room. This is exactly the reason why Roland Dietl will introduce you to the Velodynes in the usual manner and of course with pictures in the usual quality from our photo studio. Of course, this also includes a description of the technology and the diverse features of the DD+ 10, so I can devote myself to the very special acoustics in my listening room.

I almost gave up after the failed automatic calibration - and deprived myself of a lot of fun. Finally, I asked Helmut Baumgartner, who has been using a Velodyne for years, to use his measuring equipment to find out what was happening acoustically in my room. There is a peak around 30 to 45 Hertz, after which the level drops very steadily. The Velodyne's lowest frequency of use is 40 hertz, and in my room I really don't need a bass boost there: so Auto-EQ^Plus has done everything right. However, the programme still provides eight parametric equalisers, and with some of them Helmut Baumgartner shifted the application frequency to around 30 Hertz. Downwards, the subwoofer was not limited, so that it works in a range from 30 to below 15 Hertz. The level was, of course, not raised to the room-conditioned boost at the main speaker, but below 30 Hertz it corresponds to the average volume in the remaining frequency range.