T+A PDT/SDV 3100 HV SACD Transport/DAC Ringing The Changes

Ringing The Changes

In common with the MP 3100 HV, the SDV 3100 HV continues to offer four switchable digital filters that operate on all LPCM (not DSD) media, now up to and including 192kHz. 'FIR Long' and 'FIR Short' are traditional linear-phase Finite Impulse Response types while the other pair are minimum-phase filters based on Bezier polynomials. 'FIR Long' [black, upper Graph] betrays obvious pre/post ringing but has low phase distortion and excellent rejection of aliasing images (>100dB with 48kHz media).



T+A has tweaked its 'FIR Short' algorithm which now has much reduced pre/post-ringing but also has a very limited 7.7dB rejection of out-of-band images and a steep treble roll-off of –3.8dB/20kHz [red, upper Graph]. The mixed 'Bezier/IIR' interpolation filter [black, lower Graph] has some post-ringing but almost no pre-ringing but neither does it suppress ultrasonic images. Low (44.1/48kHz) sample rate data is left with a +0.75dB/13kHz treble peak and increased phase distortion. The pure Bezier filter [red, lower Graph] offers almost perfect time domain behaviour – no ringing – but a rolled-off treble of –4.6dB/20kHz with 44.1/48kHz media. PM

T+A elektroakustik GmbH & Co.
KG, Germany
Supplied by: Kog Audio, UK
01353 721089