User's Manual

User’s Guide ADI-2 DAC v2.2 © RME
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8.2 IEM Phones Output
In Low Power mode, the Extreme Power design of the ADI-2 DAC turns it into one of the world's
lowest noise headphone outputs. However, a few IEMs are so incredibly sensitive (means loud)
that, despite all the technical super specs, a faint noise could become audible (current example:
Campfire Andromeda, at least 20 dB louder as modern, already as loud categorized head-
phones).
The usual remedy is the use of an external, passive voltage divider 16 Ohm to 1 Ohm, either
self-built, or bought as a pre-made product.
Since IEMs are not only increasingly popular, but are generally more sensitive than normal
headphones, and a powerful Extreme Power output stage always entails the risk of destruction
of the IEM with wrong settings, the ADI-2 DAC has been equipped with an additional output
stage optimized for IEMs. Here, there is no Extreme Power, but extreme noise freedom, with
the same sensational low distortion as at the big phones output, but a maximum output level of
only -3 dBu. For most users this will suffice even for ordinary headphones, in particular portable
ones with the mini TRS connector. This output with < 0.1 Ohms impedance turns the ADI-2
DAC into a reference for all types of headphones, from over-ear planar up to in-ear multi-
drivers.
8.3 5-band Parametric EQ (PEQ)
While no equalization as well as listening only straight linear has been a mantra for many years,
research has proven that no ears are identical, and that especially in near-field listening (with
phones) the biological differences alone make individual equalization mandatory. No two pairs
of ears hear the same thing, that’s a fact. Additionally personal taste makes people like different
sound signatures, which can easily be copied or made more similar (equalized…) on different
headphones using a good EQ. The advantages of using an EQ outweigh any alleged
disadvantages - which so often turn out to be wrong at closer inspection.
Having used PEQ to linearize as well as to better meet personal taste with a variety of
headphones, RME found 5 bands of parametric EQ to be the best balance between occupied
DSP resources and efficient sound treatment. While it is true that on some phones rebuilding an
exact response curve needs more than 5 bands, one quickly realizes that very narrow peaks
and notches make no audible difference when compensating them. Their acoustical energy is
too low to get audible. Ignoring those narrow peaks/notches and only taking care of deviations
that require a quality factor of 3 or below, the 5 band parametric EQ turns into a very efficient
tool even for problematic phones.
This is one of the many major features that can’t be found on any similar device: a high-quality
5-band parametric EQ, usable at up to 768 kHz sample rate, easy to set up and adjust, with a
graphical display showing the resulting curve, and multiple storage places including individual
naming. So whatever EQ setting you need, it is loaded and modified quickly. And to make this
feature really useful the DAC offers three individual EQ settings - one each for rear out, Phones
and IEM.
On a related topic: These days many people suffer from hearing loss in varying degrees. No
matter if it is biological, from abuse or an accident - hearing impaired is a plague of modern
times. And – no surprise when thinking about it – it never affects both ears identically. The
number of people having one sided hearing problems is huge, but they have learned to live with
an industry that totally ignores them. Although the solution is as simple as logical – have the EQ
be adjustable independently for left and right. Basically digital EQs are calculated this way, the
common controls are just for making it easier to operate. The ADI-2 DAC includes an option
called Dual EQ – a heaven send feature for many, for sure.
Of course a 5-band parametric EQ is also suitable for speaker and room correction, another
application where separate EQ left/right setups are necessary. Using the ADI-2 DAC as DAC
for the main monitors will benefit from this and all the other typical RME features available on all
analog I/Os: Phase and Mono in various options, Width and M/S Processing.