Reverberation Time & High Frequencies
Audyssey can sound can harsh in the high frequencies when set up incorrectly. Part of this issue however is to do with how the algorithm works.
When Audyssey designed their room correction system, they were aware that the Reverberation Time (RT60) in the room contributes to the perceived loudness of high frequencies. High Frequencies in a way build up in the room resulting in your brain perceiving too much high energy in the room. However, they decided against resolving this at the time.
Both Pioneer and Yamaha were aware of the issue and they decided to tackle them in different ways.
Yamaha does this automatically – as they have DSPs already calculating the reverberation signature of the room. This information can then be used to tailor the PEQ as well to reduce this high-frequency build up.
Pioneer took a different approach with their MCACC Advanced / Pro solution – you need to run the algorithm twice: once to figure out the reverberation time using a PC connected to the receiver and then run the algorithm again once the correct time in ms has been determined to be the ideal for the adjustment of the high frequency compensation in that particular room.
While Pioneer’s solution is very exact and allows a user (more like a sound engineer with a PHD) to adjust the algorithm to their liking, it is not exactly fool-proof.
Audyssey’s Workaround
Audyssey developed the mobile app to give users the option to disable high-frequency correction in rooms where there is a harsh top end. Unfortunately, this is the equivalent of throwing in the towel and doesn’t really address the issue.
Also, Audyssey does give the users the ability to create their own custom frequency curves. Again, this is not ideal as creating the correct curve would take a lot of complex calculations to get to the correct results, and the mobile app doesn’t really allow such precision anyway, even if we could calculate it.
How does Room Treatment help?
Room treatment allows us to bring the Reverberation Time down. The closer we get to what the Audyssey algorithm is expecting, the better it will sound. However, we don’t need to get it perfect to make it sound great.
Room treatment will also usually get rid of wild frequency variations from seat to seat, resulting in a much better base to start from.
It is an incorrect assumption that modern room correction algorithms can correct for all issues within a room. It is also a misconception that you can correct for the issues across all seats equally without introducing artefacts in some seats.
The reason for this is that rooms have a significant effect on what we hear, that is they colour the sound. This effect happens for both stereo or surround sound. This colouration is caused by the room boosting some frequencies while other frequencies will be suppressed.
This is why it is important to ensure your room is optimally set up before running room correction. The more optimal the room, the better – and more consistent from seat to seat – the results will be.
However, if we simply put room treatment in the room randomly, we won’t achieve our aim and very few people have the time or money to treat all surfaces.
To make the most difference to the sound, the first reflection points in the room need to be treated for all speakers. The first reflection point is the point on a wall, ceiling or floor that literally reflects the sound from the speaker back at the listeners’ ears.
One way to find the first reflection point for a speaker is to use the Mirror Method:
- You will sit in the primary listening position
- Your buddy will use a mirror placed on the side walls and slide it around until you can see the speaker in the mirror.
- The wall will need treatment at the mirror locations.
- Now repeat the process for the next listening position / surface / speaker to find all points
What is the Best Room Treatment?
In my opinion, absorption is the best type of treatment to use at the first reflection points for most rooms. What this means is using materials such as heavy curtains, carpeting, acoustical foam or other heavy materials and soft furnishings.
Another option is to use off-the-shelf sound absorption panels that you can get in home cinema, DJ or specialist sound stores.
If you’d like to build your own room treatment and save $1000s in the process, then get this guide.
Secrets of Audyssey
If you would like to learn more about this and many more topics while getting the best performance out of your Audyssey setup, I would recommend you get the Secrets of Audyssey guide.
Get the Secrets of Audyssey guide!
There are psycho-acoustical issues for why Audyssey set up according to the manual will not sound great for 80% of people. I explain these in more detail in the guide.
Audyssey set up correctly does NOT need disabling of Dynamic EQ and Volume, does NOT need custom curves in the mobile app and does NOT need disabling of Audyssey in the high frequencies.