RME Audio ADI-2 Pro, User Manual

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User’s Guide ADI-2/4 Pro SE – v 1.0
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In this regard it is very helpful that the ADI-2/4 Pro's level meter reacts to every single sample.
When recording at 192 kHz, pops up to 96 kHz are detected, which thus only need to be about
11 µs long to become visible. But in practice nothing happens, and you can be sure: where you
see nothing, there is nothing.
In addition, there is the inevitable reality check: recordings with 6 dB of unused headroom are 6
dB quieter than other recordings that (typically) reach 0 dBFS. That may still be acceptable, but
with 12 dB or more it just becomes annoying and unusable in practice.
The available digital headroom scales with the selected gain, and is visible and can be checked
in the level meter at any time, i.e. is adjustable by the user according to personal preference. Due
to the unusual concept of the ADI-2/4 Pro SE, the
analog headroom is beyond good and evil
–
based on 5 mV it
’s 41.3 dB (580 mV).
It rumbles
Turntables are mechanical trackers, and therefore cause a variety of unwanted noise: low-fre-
quency rumble, microphonic effects, the sound of the needle in the groove, and of course the
characteristic pops caused by dust, damage and static discharge. The ADI-2/4 Pro offers help to
keep these side noises in check.
First of all an astonishing effect: switching the playback to mono, the susceptibility for acoustic
feedback (microphonics), the low-frequency rumble, but also the groove noise decreases signifi-
cantly. Since nobody wants to listen to records in mono, but the bass on vinyl is mono anyway for
manufacturing reasons, the ADI-2/4 Pro SE includes a mono-mixing circuit of the bass section
only.
RIAA Mono Bass, found in the Analog Input menu, causes almost no change to the sound,
but a significant reduction of background noise. In the Analyzer, the improvement can also be
seen in the left bands.
With not unusual bass boost, especially in combination with loudness and a quieter LP, the rumble
visible in the left bands can reach the same level as the other bands have with music. In such
cases an explicit rumble filter (subsonic or infrasonic filter) helps. Band 1 of the PEQ of the Analog
Input can be switched to high-pass filter operation, and be configured in frequency and Q factor
as desired. Combining the high-pass with the attenuating shelf filter of band 2 creates an ex-
tremely steep slope filter, with optimal passband for music, and best possible suppression of eve-
rything else.
Setup: Band 1: Low Cut, Gain -, Freq 35 Hz, Q 1.1. Band 2: Gain -12, Freq 20 Hz, Q 1.1.
This filter is directly available as PEQ Preset, number 22 (behind Clear).
Capacitors
The pickup forms an LC filter with the capacitance of the cable and the device
’s input. Depending
on the value of the capacitance, there is a treble cut or boost. RIAA preamplifiers with switchable
capacitance values therefore offer the ability to slightly adjust the sound in the high frequency
range to one's own preferences.
Thanks to its 5-band parametric equalizer, the ADI-2/4 Pro can do this much better with only one
band, even without switchable capacitances. Boosting and cutting by a few dB results in the same
change in frequency response - but here completely freely adjustable in various parameters.
Setup: Band 5 as Shelf, Q 0.8 and frequency 6.5 kHz. Gain according to taste.
Tipp: Load EQ Preset 22, set desired treble compensation with Band 5, then save Preset. With
this both functions are simultaneously and quickly available.