Measuring the quality of sound in a space is critical for several reasons. Podcast speakers need to measure the audio transmitted in their recording rooms to provide high-quality audio to listeners. Consequently, musicians need high-quality acoustics in rooms to ensure that they’re able listen to their musical pieces with natural, unfiltered sounds.
Note that it’s going to be challenging to measure acoustics without the proper tools. So, discussed below are the tools you need for this particular objective.
The Tools You Need for Acoustic Measurements
Several acoustic measuring tools are available on the market. For example, Audio Precision offers gear, like audio analyzers and option filters. But, it doesn’t mean you need to purchase all equipment related to audio quality measuring.
Nonetheless, consider the following to help you measure the acoustics in a space as accurately as possible:
A microphone responds to sound pressure. Then, the tool transforms the acquired audio into electric signals in which a measuring instrument, like a sound level meter, interprets and measures the sound.
In turn, the microphone becomes the “mediator” between the acoustic field and the measuring system. Thus, it’s crucial to choose and use the right microphone for the job.
The market offers different microphone types for acoustic measurements. Some examples are:
Also called the contact or crystal microphone, measuring acoustics using the piezoelectric microphone began sometime between the 1930s to the 1960s. During this period, this particular tool became essential to home recording studios or small-scale paging uses.
It would seem that the piezoelectric microphone became overshadowed by lower-cost electret microphones. Still, many people use piezoelectric models to measure the audio quality of rooms to this day.
Piezoelectric microphones use crystalline materials to create voltage on opposite sides of the spectrum. Here, the sound bends or deforms, allowing other instruments in the system to measure sound.
It’s relatively common to see condenser microphones in studios. These audio-capturing tools capture a large frequency range. Moreover, condensers tend to be the choice of many recording artists because of their good transient response. It means that these microphones can reproduce the “speed” of the captured sound.
But, condenser models tend to be expensive. Hence, audio enthusiasts who are on a tight budget, but also wish to measure acoustics may want to consider other options.
Nonetheless, condenser microphones are excellent options since these models tend to be sensitive to loud sounds. Thus, this particular microphone can capture clear audio from loud volumes across a relatively spacious area.
The electret microphone is a type of condenser, creating a permanent charge from the captured sound. Note that conventional condenser microphones don’t come with an existing charge, so these models tend to need external voltage sources to function.
Conversely, electret microphones don’t need external voltage sources to charge their diaphragms. Instead, these models use permanently-charged plastic elements called electrets. You can find the electrets placed parallel to a metal backplate.
Also, electret microphones are excellent for measuring frequencies in the lower-middle to high-frequency range. Therefore, it’s not ideal to use these models in measuring bass responses.
Dynamic microphones tend to be sturdier than their condenser cousins. Moreover, many models tend to have a high resistance to moisture. Acoustic measurements in a seemingly wet environment can become easier than before with dynamic models.
Moreover, dynamic microphones don’t require dedicated power supplies, unlike condenser models. But, bear in mind that many dynamic units have a smaller frequency response as compared to other microphone types.
Despite the drawbacks, dynamic microphones are still excellent acoustic measurement tools. However, users may find their uses to be quite limiting.
Choose an acoustic-measuring microphone based on factors like the purpose of the recording and the sound environment. In turn, you should acquire accurate measurements from the readings produced by these tools.
Sound Level Meters
Helping your chosen microphone to measure acoustics are the sound level meters.
Sound level meters connect to the microphone to help measure the alterations in air pressure produced by an instrument or human vocals. Although it’s essential to use a good-quality sound level meter, the readings largely depend on the quality of the connected microphone.
Nonetheless, you’ll find different pieces of information displayed on the screen of this device. Some data shown include:
- Level A-Weighted Equivalent
The level A-weighted equivalent, also called Leq or LAeq, is the acoustic measurement corresponding to the continuous sound level recorded by a microphone in decibels. Some sound level meters display LAeq, T, wherein T is the total time measured.
- Level A-Weighted Fast Maximum
The level A-weighted fast maximum or LAFmax is the maximum level reached by the audio recorded in a microphone in decibels. This element also comes with a fast time constant measured in a particular period.
Also, don’t confuse LAFmax with slow max or LASmax. The latter is the acoustic measurement recorded by the microphone in decibels in the slowest interval.
- Level Z-Weighted Impulse
The level Z-weighted impulse or LZl is the flat frequency response with no weighting. In other words, it’s the device’s estimate for the actual noise made with no filtering or weighting based on human hearing.
You can use these readings for different purposes. For example, maintain a steady volume while recording podcasts so your listeners will always hear the speakers’ voices. Hence, opt for a constant measurement in the LAeq to achieve efficient acoustic results during podcasts.
Sound engineers tend to use frequency analyzers or audio spectrum analyzers for several reasons. Professionals use these devices to measure the frequency response of different audio equipment or analyze distortion characteristics in a space.
Consider using real-time analyzers to save time and effort in measuring the acoustics of instruments, vocals, or recording spaces. These real-time audio analyzers are excellent for optimizing room acoustics and sound systems, without the need to wait for the results of the readings.
Use frequency analyzers to:
- Reveal problems on different channels and instruments: These devices can check each channel for unnecessary responses in the low-end frequencies, such as hums or rumbles.
- Work in poor audio scenarios: In a perfect world, audio enthusiasts can work in perfectly-tuned studios. But, many sound users have to deal with less-than-ideal room acoustics. Frequency analyzers help measure the ideal sound requirements in a space, allowing experts and enthusiasts in the audio industry to create high-quality audio despite the use of low-quality equipment.
- Measure room and loudspeaker response: Use the spectrum analysis produced by a frequency analyzer to help reveal the sound frequency response of a listening environment. The results allow you to fine-tune the acoustics in the area by looking for large gaps or bumps in the produced graph.
Note that some audio analyzers are better than others in measuring sound from headphones. You can search for credible online sources, such as Facebook pages, for these unique devices.
Don’t confuse sound level meters with dosimeters as both devices can measure noise levels. But, the latter are more specialized equipment than the former.
Dosimeters are ideal for use for audio environments that aren’t practical or safe for the use of a full-sized sound level meter. Some examples include locations with a high fire risk or small, confined spaces.
Use dosimeters to measure the noise exposure of construction equipment at a job site. In turn, you remain compliant to local laws so you won’t get charged by breaking noise pollution regulations. Fortunately, many dosimeters are relatively light and unobtrusive. It means you can carry these devices without breaking a sweat.
Recorders allow the capturing of different sounds for playback purposes. In other words, these devices record audio from instruments or other sound sources emitted to microphones.
Different types of recorders exist for you to use, including:
- Graphic Level Recorder
Used in situations that allow the acquisition of the evolution of sound levels, graphic level recorders allow users to see compatible writing speeds of sound level meters.
If you choose to use graphic level recorders, consider searching for models that have essential features, like:
- RMS detection
- Accurate writing speeds
- High dynamic range recording
- Ability to characterize short noise events
- Ability to study reverberation time
- Magnetic Tape Recorders
Magnetic tape recorders are compatible with various audio equipment, including HIFI sound gear. These models are ideal for capturing high dynamic ranges. But, sound engineers or audio recorders need to connect magnetic tape recorders with high-quality instruments to record accurate acoustics.
- Tape Recorders
Although the design may look dated, tape recorders can still be practical choices for acoustic recording and measurement. But, it’s critical to choose models that offer specific features, such as:
- Record frequency response at varying speeds
- High dynamic range recording
- Check cross channel attenuation
- Present the presence of band pass filters
- Eliminate low-frequency noise
- Control output signals
Always ensure that your chosen recorder is in a secure place. If the recorder’s settings become altered during the recording, you run the risk of repeating the whole recording process.
Acoustic measuring tools help you reduce unwanted noise, provide high-quality podcasts to listeners, or follow noise pollution laws. Always consider investing in high-quality audio-measuring equipment. In turn, you should capture accurate readings and recordings to satisfy specific needs.