Have you ever been watching TV and no matter how strong it made the volume, it was still difficult to hear? Always walk down a long corridor and narrow and applaud the strange accent hear an echo? Well, those are just some of the effects of distortions rooms and yes, they play an important role in their recordings. Therefore, it is important to first consider the acoustic quality of a room before you start recording an impressive, with the change in the world, songs. Once the tracks are recorded, it is very difficult or almost impossible to undo the effects of living in the stages of mixing and mastering. Therefore, to address this before you start recording.
There are volumes and volumes of information written on the subject of acoustics and most of us do not have time or energy to absorb that. The focus here is to give enough information to understand what makes a bad room for recording and how to identify problems before the record button is pressed. Ways to correct acoustical problems without spending a fortune are discussed in another goal, "Finding and correcting acoustical problems," but first, a handle on acoustics of the room will be a useful tool to achieve high quality recordings. Furthermore, knowing a little about acoustics of the room will help you choose a room that is already a good choice or the needs of small adjustments to the recording. Just know what to listen in a room.
Basically there are three acoustic properties that dominate the quality of a room, 1) room modes, 2) levels of reverberation and absorption, reflection, and 3), the hairstyle and the diffusion properties. It is true that there are other acoustic properties, but we will not win her doctorate in acoustics from here. We will try to keep it simple for us to do what you really want to do, get a good recording quality music.
I. Room Modes and Resonance
Ever play a particular note of his instrument and something in the room shook as a result? Well, that memo, press the "resonance" of that object. What is resonance? If you take a piece of string and tie one end of something and then shake the chain until you get the string to vibrate with a single arch, which is at the point where it requires the least amount of energy to shake the chain. So when you boot a stringed instrument, which vibrates at a specific frequency or frequency (ie the note in tune). The energy transfer easily back and forth from the bridge to the nut at this rate. Anything faster or slower just die faster. Take the chain connecting piece and try to change the rate at which you shake it and see how it becomes irregular. Well, the rooms also have resonances as the energy of the guitar string that transfers back and forth from the bridge to the nut, the sound in a room bouncing from wall to wall. Thus, the resonance frequency, the sound will take much longer to fade in comparison with other sounds, not the frequency of wall to wall resonance. There are other types of resonances created from more than two walls (known as mode types), but the modes of wall to wall almost always dominant in the room.
Why worry about the resonance of the room? Well, say you're recording a song that is found mainly in the key of A and the hall resonates at a frequency that is near my flat. After recording the song in the room, now there's this weird sound recording apartment that simply can not put your finger on and therefore, the room has ruined the recording. Usually, if you can not hear people talking on TV, no matter how strong you make volume is due to the resonance of the room is covering the sound. The same applies to the recordings if the room has strong resonances.
The way to know how the modes are in a room is based on the number of parallel surfaces. For example, in a rectangular room, there are three modes: on the wall opposite the rear wall, left side of the right lateral wall and floor to ceiling. Again, there are other modes of transport, but these are generally much less of a hassle compared to the type of wall to wall.
The frequency with which resonate in can be determined by the distance (D) between each wall using the formula,
F = 565 / D (mode resonant frequency of the room from wall to wall)
Depending on where you place a microphone, an MRI room can make a playing pitch (or part of the course) louder or softer. In any case, "colors" and distorts the sound recording.
Remember the example of the resonance in E flat? One room has two walls of 14 feet and a half away there is a resonance frequency of about 39 Hz, which is a very low tone in my flat.
Is there a good distance from wall to wall? No. The enemy is the surface in parallel and in particular rooms, which are square or cubic. What if I just put a lot of things in the room? Not that help? Not necessarily, especially if you just do this randomly. Carpets, curtains and furniture do not provide much damping mode (affecting the reverb image, but not anyway). There are ways to soften the mode frequencies (ie bass traps, wall wedges), but this will be discussed in a separate article, "Find and fix problems of acoustics."
Here's the Take-Away for this section:
Avoid recording in rooms with lots of parallel walls (especially square and cubic)
Irregularly shaped room offers a much better quality recording
If you can not avoid parallel walls (such as floor to ceiling), at least know what the resonance frequencies are approximate so you can use that information to correct or avoid these modes
The fact that you have found a room that has few parallel walls does not mean that the recording room is to use. There are still two other factors to consider, the reflection and diffusion.
II. Reverberation and absorption
What is reverberation? The sound bounces off all surfaces in the case of a partial or total reflection. However, unlike the echoes or direct reflections success in other areas and even other surfaces until the sound goes off. This is known as reverberation and the sum of the results of the reflections of a sound different color depending on the size and shape of the room. This is why a church reverb sounds different than a concert hall. In fact, a room with no reverberation at all is not pleasant to listen to real music, but with excessive reverberation room will make the music sound fuzzy and unclear real. Therefore, the objective is to find the right balance of reverb. However, if there was a situation where you had to choose a room with a reverberation excessive compared to a room with a little reverb, choose the room with little reverberation (ie, a very "dry" room). Why? With the development of software technology and processing power, artificial reverberation can be added to the tracks after recording. This is particularly attractive because different types and levels of reverb can be a trial for the same track. Beats packing the equipment and move to another room to see if you like reverb better. However, sometimes we find a room that has as good a quality reverb to it and want to be caught with the recording. If not, the objective to give the room a dry as possible and get ideas for a dry room are covered in the article, "Find and fix problems of acoustics."
So how do you know a reverberation room has a lot to the recording? Reverb right ear usually does not result in the same multi-track recording, always go a little less, especially if the music is a faster tempo and rhythmic. However, the first thing to consider is the total space of the room. Based on typical room professional recording studio and other sources, the rooms not less than 3,000 cubic feet should be used for recording. This is mainly because the smaller resonance modes become too difficult to reduce the use of absorption and other methods. Not to mention, it will be very narrow (for example, 3,000 cubic feet = 8 feet x 20 feet roof front to back x 18 feet ,9-from side to side). For recording, a maximum of 30,000 cubic feet should be the limit, this would be a typical basement with a ceiling of 10 feet, 75 feet long and 40 feet wide. Something bigger and have more difficult to reduce reverberation without professional grade treatments. Once you have a room that is a good size for the recording, you have to figure out if the reverb is too much for a clear recording sound professional.
There are two answers to the question: "How much reverb is too much for a room to record the music?" The first answer is the professional approach required to establish a microphone and speaker for recording a "white noise" going off to have a record of the decay of the sound. The time it takes for the reverb drop of 60 dB (decibels) is known as the time RT60 of the room. If you go to some websites musical instruments and audio equipment, selling audio analyzers that measure the RT60 of a room. However, there are cheap and there is no quick and dirty way to do it if you have burning software that shows the tracks on a dB scale (covered in Section IV). Therefore, a good reverb RT60 levels recorded music must be in the range from 0.5 seconds to 0.75 seconds. The second answer is the least sophisticated and that is to make room only as dry as possible. Then, once the tracks are recorded digital reverb can be added into the mix. Make a dry room requires some understanding of absorption and cushioning.
As much as some materials reflect sound, other sound-absorbing materials. The problem is that most absorbent materials absorb sound the same at different frequencies. For example, the curtains may absorb midrange sounds (200 Hz and 1000 Hz) well, but do not affect much smaller range. Therefore, although it reduced the reverberation in the midrange of the room now sounds Boomi. The conclusion is that the bulk is better. Fluffy pillows and curtains with a large number of folds that provide better sound absorption in the lower areas. The carpets are good for mid-high frequency range (1 kHz and above). Modes are a different animal room and things like bass traps and wall wedges will be needed, but the very idea of bulk-is-better is still valid. In general, try to have a material balance for all frequency ranges. A slight adjustment of how many items are and where they are in the room will make a big difference in the dry form of the room will get. If the room starts to sound like you're in a can, the high-end needs more absorption and if the room is too boomy, you need thicker spongy items to reduce the lower range. More on this will be discussed in the article, "Find and fix problems of acoustics."
The last topic I want to mention in connection with reverb is the sense of spatial location. If a listener is standing in a place in the room and the instrument is played in different places, the change of location is audible to listen and not just because of the different volume between each listener's ear. The reverberation build will be different depending on where the instrument is placed. One of the key is the gap of arrival. This gap between the direct sound of the instrument and when it's reverb creates a feeling of space. Therefore, sounds that have different shortcomings of arrival and reverberations to give the listener a better idea of the spatial location of the instruments in the room. Therefore, when recording in the room (especially the rooms that are not too dry), recording various instruments, very far apart as possible to give better separation of the final mix of the tracks. While in a live performance of the instruments are closer, placing them further apart during the recording will be mixed by the total recording are much larger and livelier. For much drier rooms, this is not so important, but this effect can be achieved with digital reverb if you know how to manage the configuration to emulate the feeling of spatial location.
Here's the Take-Away for this section:
Rooms with less reverb are better for recording those with more, even if the reverb has a nice sound to it.
Rooms from 3,000 cubic feet (for example, more living room) and 30. 000 cubic feet (for example, large unfinished basement) are the most suitable for recording.
Thick and soft materials for low-frequency absorption, carpets and curtains flat to absorb higher frequency.
Record each instrument in different places to get a better sense of separation in the mixed track down (farther apart the better).
So now you know that the room is irregular with some materials to absorb sound are the best candidates for recording. However, there is another consideration that has to do with the echoes called images that can ruin a recording, but in a free mode under room reverb.
III. Reflections hair and Dissemination
Although reverberation can be considered a sort of reflection of sound is actually a mix full of many thoughts, many in a pattern of decay. A direct reflection is a single direct sound reproduction where the reflection comes from a place far enough, is called an echo. In nearby scenarios, the effect is not audible ear like a second copy of the original sound. One result is a confusion of the source and the second is a flanger sound or style. It's that twangy sound you get when you clap in a narrow corridor of solid walls. In the recording, this can happen if the instrument is very close to a hard, flat surface that sends a mirror image of his instrument to the same microphone that is recording. This can also happen to record two tracks simultaneously, and each track has the same instrument recorded, but with a slight delay between them. After mixing down together, the flanger is produced.
The solution to prevent the hair that occurs in his recordings is the rule of three to one. If the instrument is 1 foot away from the microphone that is recording, microphone and then every other flat surface, reflection must be at least 3 feet or more away to avoid comb filtering effect. For example, if you are in a room with an 8-foot dry wall and the roof has a vocal mic is 5 feet above the ground, the longest distance of the singer can be away from the microphone is a foot before that occurs flanger potential recording. Another example is the overhead mics for drums. Say you had two microphones hanging over the kit for the recording and the distance from the left crash cymbal microphone directly to a foot. Then the microphone another crash cymbal on the right must be more than 3 feet from the left crash cymbal. In addition, a dry floor wall roof must be more than a foot over the microphone. The drawing at the beginning of the section illustrates this. I will not lie, the drums are very difficult to record. Therefore, it may take some time to find the correct location and the number of microphones and equipment placement in a room. However, sometimes the placement and separation of the microphones are not sufficient or space constraints limit their options.
Any flat surface (even with a large amount of absorption) can generate a reflection and therefore a potential for hair (or flange). Therefore, one way to reduce the number of reflections that could create problems as the hair is to spread the sound reflected by the change in the surface plane to something better sound dispersion. Something as simple as a piece of wood or cardboard bent outward from the wall to provide a good spread of sound. Outreach also helps improve the quality of the reverb as well. Another idea is to have things against flat surfaces or random angles and shapes of force to disperse the reflected sound in all directions in the same direction rather than a flat surface, I would. If the caves had a greater absorption of them are great locations to shoot from the walls of the cave are so full of random shapes, sizes and curves.
Here's the Take-Away for this section:
The rule of three to one: one for each foot of its instrument is the microphone recording, all other microphones and flat surfaces that are not due to three feet away from the microphone.
Getting rid of more room for large flat surfaces as possible by adding things against the dispersion of sound in random directions or just a bent piece to the outside of wood or cardboard will make a big difference.
By applying these simple ideas for selecting and building a studio, you will notice a big difference in the quality of your recordings. The more professional sounding recordings that listeners are seen as a serious musician. You do not want someone saying, "This sounds like you recorded it in his garage." A great song deserves a great recording and it all starts to the right room.
If you know a little more room to record in the next section covers some simple ideas for making acoustic measurements to assess the environment and how well you did in the treatment makes it sound better.
IV. Acoustic measurements quick, cheap and dirty
This section is a little more advanced in terms of being able to take advantage of digital recording software to make your own acoustic measurements. If you have software packages such as Cakewalk SONAR, Cubase, Digidesign Pro Tools, or other package that can record and mix audio tracks, then you have the ability to do some acoustic measurements and core analysis. Every day, I'm seeing more and more plug-ins (such as VST, DXi) to such measures of the rooms. I've even seen a number of analyzers "free" spectrum, plug-in modules for most recording software. The point is that more and more people are beginning to realize the value in making sure the room is recorded on gives you the best results and a little understanding of the acoustics of the room will help you take full advantage of these new tools. However, with your burning software can only do some simple checks on the temperature before recording.
Finding ways to
The first types of measure that we will try to get through a quick and dirty way is room resonances. To do this, you will need:
A "white noise" wave file (> 5 seconds) to play on your audio player.
A good microphone that has a low frequency response (eg, type of capacitor used for large voices or bass drum).
An audio spectrum analyzer plug-in for the recording software. In particular, one that lets you change the frequency range of what can be set below 1,000 Hz
This measurement procedure is more for before and after the test to see if they can reduce room modes. However, in the least to be able to find the modes in the frequency spectrum. In case you are not sure what a "frequency spectrum" is that this is a plot of all frequencies that are being collected by the recording microphone. If you record a single note, you will find that not only the tone, but many tones and frequencies that appear in the plot. If you record a simple drum beat trap, you will see a very wide frequency range in the plot. White noise is shown in the graph as a complete frequency horizontal flat line frequencies. Therefore, any effect of the room, and the modes appear as peaks on the horizontal line, which is why the use of white noise to find ways to room.
First step: we have to estimate that the largest room modes in the frequency spectrum by finding the largest parallel surfaces in the room. If the room is rectangular, it would be the ceiling to the floor in front of wall to rear and left side wall to the right side wall of the distances (in feet). Using these measured distances, apply the formula:
= Frequency 565/Distance
for each measured distance between large parallel surfaces.
Second Step: Place a larger speaker (eg, type woofer) connected to your sound system in the center of the room and a large condenser microphone type (eg, voice or drum microphone) about three feet away from a corner of the room (modes are the strongest in the corners). Play the sound file of white noise through the larger speakers and record it with the large condenser microphone type to be placed in the corner. Be sure to take note of the exact position of the speakers and microphone for later reference.
Step Three: Enter the recorded sound file on your frequency analyzer and approach which calculates the room mode frequencies. Note: some frequency analysis programs (or plug-ins) will not let you change the interval to calculate the frequency spectrum and this may make it difficult to see the skin so the plot frequency (ie, the low resolution of low often has "softened" by the ways in which the calculation of the plot). Therefore, finding a frequency analyzer program (or plug-in) that allows you to adjust the range so you can get a better resolution even in the lower frequencies (10 hertz), where the modes is likely to be. FYI: a fall on the peaks of only 3 dB, the volume has been halved and a drop of 6 dB, the volume is now only 1/4th the original.
Step Four: Add bass traps, full of corner and otherwise reducing materials to cut modes and repeat the measurements in the previous step. Compare the spectrum before and after seeing the amount of reduction that have been able to achieve.
Reverberations good
Let me reiterate that the drier the environment (ie, less reverb), the better for the registration and this is mainly due to advances in computer technology and digital emulation makes it easy to create very realistic reverb artificial sounds. This means that the user of the application of reverb knows what they are doing (see the slow mixing of this series). However, you may want to see how dry the room before you begin configuring your computer for everyone in the recording. Therefore, this section shows a little quick trick to get a rough estimate of the level of reverberation of the room. I also note again that there is a growing number of programs and plug-in for this and that might be of some value to you to do a quick internet search for their own benefit.
To make the check-quick and dirty reverb level, you need a set of poles or balloons (yes, I said balloons) and a microphone. Given the choice of balloons or a stick, pick up the balloons. Place the microphone somewhere near the center of the room and begins recording when the room is very quiet. While recording, pop a balloon with a pin or hitting the sticks together once. Do this every 5 seconds for a series of pops / bangs to see in your recording software.
In the recording software, you must be a way to set the scale in the wave view window in decibels (dB). Once you have the whole scale, zoom in one of the POPs in the view window of the waves.
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Room 200-275In view of dB, the pop (or lace suit) will not withdraw completely to zero, the waveform data that is left is the background noise of the room and electronics (ie background noise). The RT60 is the time it takes to pop to decay 60 dB, but in most practical situations of decay is lost in background noise before decaying to 60 dB. Therefore, it is necessary to draw two horizontal lines, one from the top of the pop wave and the second 60 dB below that line (for example, if the first was -10 dB, then the second would be at -70 dB ). Using a ruler, is aligned with the peaks in the fall of the intersection of the second horizontal line with the straight edge indicates the time about RT60. In the picture above, the RT60 time is 0.33 seconds, which is a dry, well to record in Keep in mind, they are trying to get a rough idea of the RT60 time, there are more precise methods, but "we trying to keep it simple and cheap.