Bad acoustics in my living room (with sound samples)
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What's this all about? I'm interested in and write about a wide variety of topics - economics, psychology, marketing, music, etc. I prefer writing long articles to short posts and don't update very often. Article Archive | Contact Me. More of me: Photography; Twitter; Facebook; LinkedIn Search Recent Activity Why the Major Chord is Happy 6 Steps to Amazing Blogging, Social Media & SEO The 5 Basic Marketing Activities Comparing the Presidents: 2012 Election Edition How to find a job. Being Productive with only vaguely defined goals or How do I find time for it all? 8 Affiliates Scams You Need To Look Out For. Stores and Magazines What 100 years of book sales tells us about human nature Addiction by Design The Four Types of Traffic The US Government Budget & Debt (Obama Edition) Magic Happens Here A Complete Waste of Time (small & free video games) (updated) My Favorite Smallware (updated) List of Outliners Popular Pages My Favorite Smallware Ohms, Amps & Speakers The National Debt A Complete Waste of Time (games) The Google Proxy Global Oil Production & Consumption Comparison of Outliners Room Mode/Standing Wave Calculator The Triangle Problem The US Trade Deficit Bad Acoustics In My Living Room (With Sound Samples) By sharing with you some samples of poor acoustics, you'll be able to recognize and diagnose them in your own environment easier. I had no idea just how bad the acoustics in my livin room were until I bought an ECM-8000 test mike from Behringer. Listening to things through the mike rather than with my own natural ears, you can hear all the flaws. Conversation and television become too garbled and "smeared" to understand. Boomy at some frequencies, and thin at others, I was surprised at what I heard. Our ears compensate for a lot of laws, but microphones are cold and unforgiving. It's better to fix the problems in your room than to record them or allow your mixing environment to be influenced by them. These sound samples are designed to open your ears to the problems you may be hearing subtly now, but your ears and brain remove from the equation. Flutter Echo This is the echo that occurs between two parallel walls. High frequency sound bounces back and forth without being absorbed or diffused and rings, very much like the feedback you get when you put an open mic too close to the speaker. Actually, it's very similar to feedback, only in a purely acoustical environment, so if there's no sound source feeding it (like the amp), it eventually dissipates. Usually in a matter of seconds. Think of this as like being between two mirrors, and looking at a reflection that goes on into infinity. The better the reflectivity of the two surfaces, the longer the flutter echo lasts. Room Modes Bass frequencies also travel back and forth without dissipating. The difference here being that because bass frequencies are so large - some the size of your living room - they create huge "waves" of sound with high and low points in your room. Some people believe that making the walls non- parallel will help eliminate room modes because the wave will be misdirected sleightly each time it bounces and dissipate faster. While there may be some truth to this statement, what this does is create a more unpredictable environment with "hot spots" in different locations. Fill your sink 1/3 to 1/2 of the way full of water (or a plastic tub of water is even better because you can shake the sides and rock it back and forth). Then use your palm to start moving the water in one spot up and down. Your hand is now influencing the water the same way a low frequency sound source influences the room. You'll find that different frequencies - different rhythms - influence the water in different ways. Some rhythms will cause the water to start rocking back and forth quickly, while others just sort of splash around. Others work against the wave as it bounces off the opposite wall. When you have the water going back & forth in a strong motion you'll find some areas are highly affected, while others seem relatively calm. You'll also notice that different frequencies cause different peaks and valleys, and where you start is less important than the dimensions of the tub. Drop tiny pieces of paper in the water if you're having a hard time seeing the movements. Comb Filtering Comb Filtering is reverb that crowds the original signal. The peaks & valleys of it's waveform combine with the original and emphasize certain frequencies while cancelling out others. A lot of people end up with some nasty comb filtering when they apply reverb in a heavy handed manner, or don't add a few milliseconds of delay in before they do it. The result is a nasty, metallic, thin sounding signal. The extreme version is the "in the toilet" swirly wooshy sound. I discovered a neat trick when recording guitar amps early on. I'd stick an empty coffee can over the mic and you'd get a fun, thin sound. I've been trying to replicate that all day today, but I don't have any empty coffee cans. That reminds me, this sound is also similar to "putting a seashell up to your ear" or cupping your ears. Very similar to your phase or flange effect isn't it? Well, in a sense, it is a phase effect because it's delaying some of the signal by just enough to cause it to be out of phase with the original signal. Samples The following samples were made with my Behringer ECM-8000 test mic. It's omnidirectional and reasonably flat. It makes my room sound a lot shittier than my ears normally do, though you can't
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Transcript of Bad acoustics in my living room (with sound samples)
What's this all about?
I'm interested in and write about awide variety of topics - economics,psychology, marketing, music, etc. Iprefer writing long articles to shortposts and don't update very often.
Article Archive | Contact Me.
More of me: Photography; Twitter;Facebook; LinkedIn
Search
Recent Activity
Why the Major Chord is Happy6 Steps to Amazing Blogging,Social Media & SEOThe 5 Basic Marketing ActivitiesComparing the Presidents:2012 Election EditionHow to find a job.Being Productive with onlyvaguely defined goals or Howdo I find time for it all?8 Affiliates Scams You Need ToLook Out For.Stores and MagazinesWhat 100 years of book salestells us about human natureAddiction by DesignThe Four Types of TrafficThe US Government Budget &Debt (Obama Edition)Magic Happens HereA Complete Waste of Time(small & free video games)(updated)My Favorite Smallware(updated)List of Outliners
Popular Pages
My Favorite SmallwareOhms, Amps & SpeakersThe National DebtA Complete Waste of Time(games)The Google ProxyGlobal Oil Production &ConsumptionComparison of OutlinersRoom Mode/Standing WaveCalculatorThe Triangle ProblemThe US Trade Deficit
Bad Acoustics In My Living Room (With SoundSamples)By sharing with you some samples of poor acoustics, you'll be able to recognize and diagnose them inyour own environment easier.
I had no idea just how bad the acoustics in my livin room were until I bought an ECM-8000 test mikefrom Behringer. Listening to things through the mike rather than with my own natural ears, you canhear all the flaws. Conversation and television become too garbled and "smeared" to understand.Boomy at some frequencies, and thin at others, I was surprised at what I heard.
Our ears compensate for a lot of laws, but microphones are cold and unforgiving. It's better to fix theproblems in your room than to record them or allow your mixing environment to be influenced bythem. These sound samples are designed to open your ears to the problems you may be hearingsubtly now, but your ears and brain remove from the equation.
Flutter Echo
This is the echo that occurs between two parallel walls. High frequency sound bounces back and forthwithout being absorbed or diffused and rings, very much like the feedback you get when you put anopen mic too close to the speaker.
Actually, it's very similar to feedback, only in a purely acoustical environment, so if there's no soundsource feeding it (like the amp), it eventually dissipates. Usually in a matter of seconds.
Think of this as like being between two mirrors, and looking at a reflection that goes on into infinity.The better the reflectivity of the two surfaces, the longer the flutter echo lasts.
Room Modes
Bass frequencies also travel back and forth without dissipating. The difference here being thatbecause bass frequencies are so large - some the size of your living room - they create huge "waves"of sound with high and low points in your room. Some people believe that making the walls non-parallel will help eliminate room modes because the wave will be misdirected sleightly each time itbounces and dissipate faster. While there may be some truth to this statement, what this does iscreate a more unpredictable environment with "hot spots" in different locations.
Fill your sink 1/3 to 1/2 of the way full of water (or a plastic tub of water is even better because youcan shake the sides and rock it back and forth). Then use your palm to start moving the water in onespot up and down. Your hand is now influencing the water the same way a low frequency soundsource influences the room.
You'll find that different frequencies - different rhythms - influence the water in different ways. Somerhythms will cause the water to start rocking back and forth quickly, while others just sort of splasharound. Others work against the wave as it bounces off the opposite wall.
When you have the water going back & forth in a strong motion you'll find some areas are highlyaffected, while others seem relatively calm. You'll also notice that different frequencies causedifferent peaks and valleys, and where you start is less important than the dimensions of the tub.Drop tiny pieces of paper in the water if you're having a hard time seeing the movements.
Comb Filtering
Comb Filtering is reverb that crowds the original signal. The peaks & valleys of it's waveform combinewith the original and emphasize certain frequencies while cancelling out others. A lot of people endup with some nasty comb filtering when they apply reverb in a heavy handed manner, or don't add afew milliseconds of delay in before they do it.
The result is a nasty, metallic, thin sounding signal. The extreme version is the "in the toilet" swirlywooshy sound. I discovered a neat trick when recording guitar amps early on. I'd stick an emptycoffee can over the mic and you'd get a fun, thin sound. I've been trying to replicate that all daytoday, but I don't have any empty coffee cans.
That reminds me, this sound is also similar to "putting a seashell up to your ear" or cupping yourears. Very similar to your phase or flange effect isn't it? Well, in a sense, it is a phase effect becauseit's delaying some of the signal by just enough to cause it to be out of phase with the original signal.
Samples
The following samples were made with my Behringer ECM-8000 test mic. It's omnidirectional andreasonably flat. It makes my room sound a lot shittier than my ears normally do, though you can't
really tell from these samples what the room sounds like to ears. The noise around 16k is mycomputer fan. I recorded them all at the same level without changing any settings, and did no post-processing, other than to convert them to mp3's.
Note: The acoustics in your room will affect the way you hear these files. I recommend, especially forthe Room Modes file that you listen to them via headphones... and keep your finger on the volumecontrol.
Flutter EchoI stuck the mic up by the ceiling, aimed at the corner. Then went to the opposite wall andstarted clapping.Room ModesSine Wave Sweep from 200 to 20hz. Around 20 seconds into the sample, a huge sound wavecame at me from all around and nearly made my ears pop. The noise you hear is me movingaround. Also take into account the limitation of the speakers.Comb FilteringI hung the microphone inside a metallic thermos bottle... no coffee cans being on hand.
Other Articles in this Series
Bad Acoustics In My Living Room (With Sound Samples)Acoustics Crash Course 1 - ModesAcoustics Crash Course 2 - ReflectivityRoom Mode / Standing Wave CalculatorRoom Reverb / Sabine Calculator and Charts
See also Ethan Winer's article "Acoustic Treatment and Design for Recording Studios and ListeningRooms"
page first created on Saturday, April 19, 2003
© Mark Wieczorek
