Lyngdorf Audio Room Perfect TDAI 2200 - Manual (Page 7)

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Also, if you have imported an actual measurement into the DSP, the ‘instant response’ feature
allows you to immediately see the simulated result of your corrections.
For the room response measurement we have chosen a 1/6 th octave band smoothing response
for the ATB system, a change which helps to identify peaks and dips in the response better
than the commonly used 1/3 rd octave band smoothing.
When designing filters and equalization there are a few rules of thumb to follow:
1. Peaks in the room response can usually be attenuated without risk since it is always ‘safe’ to
send less energy through the system (no danger of overloading amps and speakers).
Also, psychoacoustics research shows that peaks are normally perceived to be much more
annoying than dips. Therefore a peak in the response is the most important element to
‘attack’.
2. With dips, caused by room modes or direct reflections from walls or other boundaries, you
must be very careful when trying to apply correction.
If a dip is caused by the frequency response of the speaker itself, it can most often be
corrected/equalized. But if it is caused by, say, a floor reflection it cannot be equalized as the
reflection will persist, no matter how much sound energy is pumped into the room at that
frequency from the specific source to the listening position.
Therefore when trying to compensate for a dip in the response it is important to repeat the
ATB measurement and if the correction/equalization has only marginal or no effect you should
not do it. If you apply it, the result will just be that you overload the amps and speakers – for
no benefit at all.
RoomPerfect™ (optional)
The room – the weakest link in the chain
Most high-end products are developed in sonically ideal – or near ideal – listening rooms with
optimized dimensions and acoustic treatment.
However, in reality we all place our audio system in different rooms. Unlike sterile lab rooms
we also typically fill our listening rooms full of furniture, curtains, bookshelves etc because we
also want to use them as living rooms!
The actual performance of a speaker is known to be highly dependent on the acoustics of your
listening room and your listening and speaker positions. To put this into perspective our
extensive measurements in different rooms show that even when you put a high-end system
in a well-controlled room, peaks and dips between +10 to –20 dB in the frequency response
are more the rule than the exception! So, creating a “linear” sounding audio system by
improving the linearity of each component 0.2dB doesn’t actually help much.
Also, it is quite obvious that even if the greatest of care is taken over tweaking the system
with cables, interconnects, power stabilizers etc. none of that will never compensate for 10 –
20dB peaks and dips in the frequency response.
So, it’s clear that the room is the weakest link in the chain which is why we decided to do
something about it. We believe in the principle that if you ‘strengthen’ the weakest link you
have the biggest potential for making an improvement!
Room correction so far
Today most room correction is carried out based on a single measurement at the listening
position, i.e. you are trying to solve problems in a 3 dimensional sound field with a 1