Olaf_HH schrieb:Simulier den mal :-)

Cap schrieb:Das dürfte sich mit dem 2x4 HD erledigt haben, allerdings ist das auch teurer. Das steht dann in keinem Verhältnis mehr zum Einsatzzweck (ursprünglich Soundbar, jetzt TV-LS).

Zitat:Equalization is achieved by a 7 dB peak in the frequency response of the DSP. This form of equalization is advantageous because the response drops below 50 Hz towards 0 dB, thus relieving the driver somewhat of excessive excursions below the peak frequency. The equalized woofer response is 3 dB down at 45 Hz.

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Any DSP unit has limited analog input and output capability. For the processor used the maximum Full Scale input and out voltages are 900 mVrms. The power amplifier in this example takes a 900 mVrms input to reach full 80 W of output power into 8 ohm. Looking at the equalization curve and the signal level diagram we see the following limitations:

• The power amplifier requires 900 mVrms or 2.54 Vpp input voltage for 80 W output. This input voltage is also the output limit for the DSP DAC. The corresponding 50 Hz input signal to the ADC is 7 dB lower or 1.13 Vpp. This is 7 dB below the 2.54 Vpp input limit of the ADC.
  
• A (2.54 - 1.13) = 1.41 Vpp sinewave at 5 kHz could be riding on top of the 1.13 Vpp, 50 Hz sinewave, when the ADC input and the woofer DAC clip.
  
• The 1.41 Vpp, 5 kHz sinewave signal would produces a 16 W output for the dipole fullrange, if the tweeter channel had 0 dB gain. At -10 dB of gain the output is merely 1.6 W. A single 5 kHz sinewave at the clipping level of the ADC would deliver 8 W to the fullrange.
  

The spectrum between 50 Hz and 10 kHz is evenly divided on an octave basis by a 700 Hz crossover. Having 5 dB to 10 dB less peak signal capability for the upper frequency range is of some concern to me. Putting 10 dB of gain between DSP and power amplifier would make full use of the amplifier's capability and raise the noise floor, which is of little concern. But after many hours of listening to the LXmini I have only run into the expected woofer driver excursion limitation. So I am happy. The drivers are the limiting elements and not the electronics.
The range of the miniDSP 2x4 input ADC is set to 0.9 Vrms by default. It can be increased to 2 Vrms by resetting two internal jumpers in case a multi-channel volume control is used downstream of the miniDSP 2x4.

fosti schrieb:Wir leben in einer Gesellschaft, wo alle hoffen, das es einem alles vor die Füße fällt......
Und Ralf, das ist ncht persönlich gegen Dich als TE gemeint. Muss man ja heute immer dazu sagen :prost:

Cap schrieb:Ich nehme mal an, dass das Umstecken der Jumper beim 2x4 der erste Handgriff nach dem Auspacken ist und daher keiner besonderen Erwähnung bedarf.