Home Studio Acoustics: Part 1

     We already know that home studios are not going away.  It is best to embrace this shift in the recording industry and figure out a way to make it work.  Many professionals criticize homes studios because they are often run by amateurs, and they don’t necessarily use the best equipment or have the best acoustics.  Recording and mixing music is all about the acoustics.  If the acoustics of the space are decent then low grade equipment can still be useful.  However, bad acoustics can make even the best equipment completely useless.  This two-part blog post will overview some effective ways to strengthen your room’s acoustics and give you a better mixing environment as a result.  In this first post we will go over some ways to treat the inside of your room.

     Let’s assume that for this post that you live in a space where knocking down the walls and building from scratch is not an option.  This is probably the most realistic scenario.  So what do you do?  Well, you have to treat the room in such a way that you eliminate reflections and room resonances.  However, sound isolation is also very important if you live in an apartment building and have neighbors.  Sound isolation techniques will be covered in the second post so let’s focus on reflections and resonances for now.  Small rooms are very tricky to deal with because they produce room modes within the audible frequency spectrum.  A room mode is the natural resonance frequency of a room dimension.  The equation is the speed of sound/wavelength.  The wavelength in this case is the dimension of the room.  So if our dimension is 19ft, then our resonance frequency is 1130/19=60Hz.  This means that we will have issues within the 60Hz area and some multiples.  

     These resonant frequencies will alter your perception of the mix and this can result in unbalanced mixes.  Reflections are another key component to small room acoustics.  Since the dimensions are shorter the reflected sound arrives at the listening position with strong amounts of energy. This too can alter the perception of the mix and cause phase issues.  So let’s talk about some effective ways to treat these issues.

     After figuring out the frequencies that are giving you trouble you can begin to pick out some acoustic treatments.  Companies like Primacoustics and Auralex provide some affordable consumer grade acoustic treatments that can get the job done.  Don’t just slap foam all over the walls though.  Place some absorption directly on the wall behind the speakers and at early reflection points to eliminate sound reflecting off the walls towards your ears.  Next, it is wise to pick out some diffusion to place on the wall behind the listening position.  This will help scatter the sound around the room so it does not create a standing wave.  A cost effective way to create diffusion is to use furniture elements like a book shelf filled with books.  The various depths and densities of each book create a great diffusion element with some absorption as well.  

     Everything I have discussed so far is great for mid to high frequencies, but we know that low frequencies are what’s giving us the most trouble.  Low frequencies like to hangout in corners so placing high density objects there can help absorb some low end.  The companies mentioned before also sell some corner bass traps to help with this problem, but it is not necessary to spend a lot of money.  You just have to understand basic acoustics and absorption properties.  Many people will say to place egg cartons on the wall for diffusion and absorption.  This is not a good technique.  Egg cartons do provide some absorption, but it is only in the high frequencies.  We know that small room suffer most from low frequency issues, so egg cartons aren’t the best solution.  

     This ends this installment of home studio acoustic basics.  Next post I will discuss sound isolation methods for your home space.  Future posts will revisit the acoustic treatment topic so stay tuned. 

-Jon          

Audio Networking: AV Meets IT

     The world of analog audio has been on its way out for some time, and digital audio has been moving in.  Now there is a new culprit entering the scene, and that's networking.  The integration of digital audio means audio networks can now gain massive territory.  To illustrate, I will paint scenario.  

     The old way of designing an audio system was through analog means.  There would be a mixing board with physical inputs, analog cabling routing to processors, and then an output to speakers.  This is one of the simplest forms of an audio system.  In the analog domain an audio network gets messy as it grows in size.  This is due to the cabling, power, and space requirements. 

        Today’s technology has taken the world of network routing, and applied it to audio system applications.  Think of how your Internet and corresponding devices are set up.  You have your router that grabs the Internet from your provider to supply to your household.  Then every device you want on the network connects to that router somehow; whether it is physically or wirelessly.  All of those connected devices can now talk to each other and the Internet.  So, now you can print wirelessly, connect to the Internet, and share files remotely with other computers in your household.  These are the basics of networking and now you can do it with audio systems.  

     Audio is starting to use the same blue Ethernet cable that is used for Internet networks.  Ethernet has the capability to carry more audio signals than an analog cable that can only carry one.  So already there is an advantage.  Manufacturers are also developing digital audio devices that have the capability to talk to one another intelligently.  Addresses are assigned to each device that is attached to the network and with little manipulation from the user; these devices can talk to each other.  This is called Audio over Ethernet (AoE).  More commonly you will see it described as a Cobranet or Dante system.  These are two common systems that allow audio over Ethernet at great speeds.  Another advantage of having audio devices on a network is the ability to control and monitor them remotely.  There are some brands that allow the end user to monitor and control a device from anywhere in the world through the Internet.  The manufacturer sets up a web portal that allows the user to log in to his/her device(s) and control or monitor.  This is huge because I have witnessed first-hand, times when the crew needed access to a piece of gear but didn’t have the authorization, and the only guy that did was not there.  Having network capabilities eliminates that problem from occurring, or at least greatly reduces it. 

     So hopefully you can start to see how much of an advantage it is to have audio systems set up in a network configuration.  It allows for more complex systems, reduction in cabling, and expansion of use.  However, these systems are far more complex to design and install.  This sums up my introduction to the world of networked audio.  There will be future posts delving deeper into the equipment and techniques used to design and operate these systems.  

-Jon

The Acoustical Society of America (ASA)

     In the acoustics industry there is an association that every professional and student should be a part of or at least made aware.  This association is the Acoustical Society of America.  The ASA is the national group for all professionals and students in the industry.  So let's talk a little bit about what the ASA does and why you may want to join.

     The ASA is an association aimed to bring together professionals and students in the industry to help provide and guidance, resources. and networking opportunities.  They hold meetings and seminars that allow everyone involved to get together and network while learning something about the current industry trends.  So if you are in an acoustics related profession, why should you join? Wellllll...

     Let's start with their website.  The ASA site houses an abundance of resources that can be accessed.  Journals, periodicals, textbooks, research papers, and more can all be accessed and downloaded.  To me this is reason enough to join.  If you are a student in an acoustics related program then the resources that the ASA provides are very valuable.  The website has a list of grad programs around the country and contact information.  This is huge for someone looking for a good grad school.  There is also a forum that members can access to discuss topics and get advice about career aspirations.  The ASA website serves as a hub for all things acoustic in the country.  There are links to organizations, companies, and even job postings.  

Being a part of this organization is such a great asset to have.  There are so many ways to grow your professional network.  You can start discussions with people, ask or give advice, and attend the events to network in person.  The ASA provides ways for young professionals to gain exposure in the industry, and for veteran professionals to share their knowledge.  So to wrap things up, if you are a professional and you do anything with acoustics, then the ASA is a must join!

-Jon    

The Subjectivity of Noise

     There is noise all around us.  City streets filled with roaring buses and people on their cell phones.  There is so much noise around us that we tend to ignore it.  Ignoring the noise does not make it go away. Noise pollution is often the last thing to be considered when designing a building.  Noise is considered to be any unwanted sound.  This definition is a bit subjective since everyone has different ideas of what can be categorized as unwanted sound.  Someone may say the sound of their neighbor banging away on drums at midnight is noise, while the drummer perceives it as music.  While the threshold of what delegates wanted from unwanted sound is blurry, there are many things that are considered noise in which society is in agreement.  Below is an amusing picture that helps to illustrate the subjectivity of noise.

The sign above states that "unnecessary noise is prohibited," but what constitutes unnecessary noise? This sign does not make sense because what is considered noise to someone may be pleasing to another.  And is there such a thing as necessary noise?  If noise is defined as unwanted sound then necessary noise would imply that it is in fact wanted, therefore contradicting the definition.  So all this sign does is produce a paradox.


     Noise pollution is a growing concern in the world today and before we can tackle this issue, we need to first define the types of noise that are polluting the environment. To do this we must look at the noise sources that society is in agreement. Such sources can include traffic, trains, rooftop HVAC units, and loud machinery. Noise sources are location based so in a school, noise can be the classroom next door being too loud. This is a noise source for students in the other class. They will have trouble paying attention and studying when noise from the class next door is being transmitted into their learning environment.

   The following LINK will show an article about rising noise levels in New York City.  The noise level are getting so bad that hearing loss is being caused over extended periods of time.  Exposure to high decibel levels for extended periods will cause hearing damage, and when the people of New York are experiencing 70dB and up for more than 8 hours a day it begins to take its toll. 

     Future blog posts will dive deeper into these various sources of noise as well as common methods of treatment.  For now, understand that the best way to treat noise is at the source.  Engineering said device to not emit strong noise levels is the best solution.  However, most of the time it's very expensive and time consuming to go this route.  Click HERE to see some information on types of noise and some common ways to treat them.  This will help to further explain what I have just talked about and also serve as a transition into future topics. 

-Jon Owens
Audio Engineer/Sound Designer/Acoustic-AV Consultant
www.jon-owens.com