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High Resolution Audio Needs Higher Resolution Rooms

MikeSorensen June 13, 2012 No Comments
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Today’s digital recording and playback technologies are detailed in their presentation and full of more information than our analog technologies of the past. There are more dynamics since we have more head room to record within and we also have a lower noise floor. A lower noise floor goes the other way in providing for more resolution in our recordings and playback sources. With higher speeds in sampling rates and more storage capacity in our digital formats, we must have a room that is capable of revealing this digital dynamic sound quality and a room that has the same high resolution capacities.

Digital Audio and Video

Digital audio technology is as revealing as digital video technology. All you have to do is look at the news broadcasts that are done in the digital domain. When you see the talking heads up close, you realize that they are covered in makeup. They have makeup on so thick that they look like mannequins. Makeup covers up imperfections in their skins, so they look smooth for the digital camera which reveals much more than the older analog versions. Digital audio won’t let you cover up anything. Everything is present and ready to be heard.

Digital Audio

With digital technology, we can hear much more of the fringes of our music. We are allowed to hear the edges of our music where one note ends and another begins. We have real layers to our recordings and each group of musical frequencies can be heard even though they occupy the same frequency range as another vocal or instrument. The attack and decay of our vocals and instruments are more detailed and defined. Every note is heard from beginning to end. Our rooms that we record and playback in need to have equal or better resolution than our digital formats.

Digital Bass

Digital bass energy is amazing. There is a detail to bass with digital that we never had with analog. One can hear bass note attacks and decay with a new, more revealing definition. The beginning of each bass note starts, sustains, and then decays with a clarity and definition that begs for more attention. The bass attack and decay of our rooms must be heard with the same clarity and definition. We must make sure that all low frequency resonance issues are dealt with in the proper manner and that all bass energy is able to heard regardless of the size of one’s room.

Room Resonances

We must locate and treat all low frequency room resonances because they will interfere with our bass presentation. Low frequency room modes will smother or blur any digital presentation efforts to be clear and defined. Resonances must be treated with the proper low end absorption treatment that will perform at the rates and levels of absorption necessary to minimize the resonance’s levels. This is not easy and requires many different acoustical approaches.

Building A New Room

If one is fortunate to be building a room from scratch, special care must be taken to choose the correct room size. The proper room size will go a long way to minimizing bass issues in our room. There is no substitute for a room with the proper dimensions where all room modes are taken into consideration and planned for by selecting the correct room dimensions. With a room that does not have the proper dimensions to accommodate low frequency energy, one is always playing catch up in chasing low frequency energy issues.

Low Frequency Absorption Must Work

Low frequency absorption technologies within our high resolution room must work and work very well. They must address the troublesome frequencies with certainty and performance. They must be consistent and predictable and perform at the proper rates and levels of absorption to really have an impact on reducing the amplitude of low frequency room modal issues. One can not use foam to solve low frequency resonance issues, despite what acoustical product’s manufacturers claim.

Vibration Control

There is also a balance between building walls and ceilings. Both must have the necessary rigidity to contain and manage the low frequency energy that is so necessary to our bass definition within our rooms. Sound pressure energy causes our room surfaces to vibrate. Multiple layers of materials must be used for vibration isolation and control. Low frequency energy is all about excess pressure in our rooms that is trying to escape. This excess pressure produces vibrations within our rooms and the walls and ceilings that try and contain this energy. Multiple layers of materials all with different densities, slow vibrations down and reduce their amplitude. With less structural vibrations, we have less room sound from the structure. Less room sound means that there is more room for music to be defined and heard without the room adding its own sonic signature.

Existing Room

If we have to use an existing room for our playback or recording venue, then we may have to make the room smaller if its size does not lend itself to creating room resonances that are far enough apart that they will not muddle our recordings or playback music. Since room resonances are dimensionally dependent, one must take the existing room and make it fit a predetermined ratio of height, width, and depth that will minimize room modes. Making the room physically smaller to fit into the correct dimensions must be done with the proper technologies. We can not just add a new wall to the existing room. The new wall or walls must be designed to absorb all excess energy and at the proper rates and levels, so that we control and manage low frequency issues at the source from within the room.

Middle And High Frequency Control

Our middle and high frequencies and the reflections that they produce, must also be addressed in the same high resolution manner that we dealt with on our low frequencies. Care must be taken to reduce just enough of the middle and high frequency reflection to slow the reflection down, so it will reach the listening or monitoring position after the direct sound from our source. Diffusion and absorption technologies are available to meet this challenge.

Diffusion vs. Absorption

Diffusion can take the reflection from the room boundary surface and spread it out into little reflections, if you will, that will not have a sonic impact at our listening or monitoring position. Absorption technologies are available that will reduce the energy level of the reflection, so it will not be laced with the direct sound from our source. As with low frequency control, this absorption must be done at the proper rate and levels to insure a naturalness and realism to our music and vocals. We do not want to destroy our middle and high frequencies through excess absorption in order to control the reflection.

Digital playback and recording technologies are at their highest resolutions ever with today’s recordings. The information that is revealed today is full of subtleties and nuances that can be heard if our room has the proper resolution to match the digital source technologies. Room resonances, especially in the low frequency area, must be dealt with by choosing the correct room size to start and then choosing the correct low frequency sound absorption technologies that perform at the required rates and levels of absorption to manage the low frequency pressures in a consistent and predictable manner. Middle and high frequency reflection control must meet the same rate and level of absorption standards if one chooses sound absorption technology. Diffusion is also available to reduce the amplitude of the reflection without any signal loss.

MikeSorensen

I am a structural engineer as well as a master furniture maker. I design cabinets for low frequency, activated carbon absorbers. Connect with me on Google+

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