Why do certain songs sound louder than others even when they’re played at the same volume?
In: Technology
Most of these other comments are focusing on actual loudness differences. But perceived loudness can be a psychological thing too. For example, I make a lot of rap beats. If I want the instruments to seem really loud, I might add a crash cymbal at relatively low volume. Your brain notices the crash cymbal in the mix and knows that crash cymbals in real life are loud. Since the other instruments are loud relative to the crash cymbal, your brain decides that these other instruments must be super loud too.
Okay, so one, keep in mind the difference between loudness and volume. Loudness describes the objective amplitude of a sound wave. Volume describes the relative loudness of a sound coming from a speaker. Loudness is measured in decibels, which are units on a logarithmic scale that describes the loudness of a sound based on its energy. Volume is measured, typically, as a percent or a linear value. The loudness of a sound that’s recorded can be, say, 12dB (dB is short for decibels). If recorded on a microphone capable of perfectly capturing the sound, and then played back on a speaker with the same power output at 100% volume, then the playback will also be 12dB.
Second, keep in mind that not all speakers are created equal. The power of a speaker’s driver, the magnet and coil transducer that converts the electrical signal sent to the speaker into sound, varies based on size and specifications. The size and specifications affect that frequencies it can reproduce, as well as how loudly those frequencies can be reproduced. Some speakers will recreate the exact loudness of a sound at 100% volume, but others can only output less and will never reach the same loudness while yet others can max out at much higher values, and require a low volume setting to get the same output.
Thirdly, keep in mind that there is no standard to how loud sounds in music can be when mastered, though there is a physical and digital limit, based on the speakers reproducing the sounds and the hardware the music is mastered on. As well, an amplifier (which is any hardware or software capable of boosting specific or general frequencies of sound) can take a 12dB sound and multiplying it at any factor, resulting in the output sound as much, much louder or softer.
So, to boil it down. Volume is like a multiplier scaling from 0 to 1, that modifies how loud a given sound plays. Low sounds are not suddenly boosted to the same loudness as loud ones just because the volume is 50%. Rather, they’re both half as loud as they could be if it were on 100%. Speakers of different types can result in different loudnesses at the same input volume, since it’s a factor of their maximum power output. And lastly, in general there’s no standard or rule that says sounds have to be within a certain range when recording, mixing, and mastering music.
As a result, there’s a thing people refer to as the “loudness war”. Where commercials have progressively gotten louder and louder especially compared to the program they air with, since the businesses making them want to try to ensure they get the viewer’s attention. Some places have debated and passed bills stopping this practice.
Think about recording into your phone, you can record a soft whisper or record yourself yelling. The yelling will be louder. The same can happen to music.
There are a few factors:
Frequency/special content plays a role. We don’t perceive all frequencies the same in terms of loudness (see equal loudness curves). So one song might be perceptibly louder because of its heavier in frequencies you are more sensitive to.
Dynamics. No song is exactly the same volume for its entire length. The relationship between the quiet and older parts, or the instantaneous peaks versus the sustain portions can have an impact in how you perceive loudness. Also, longer sounds sound louder than short ones at the same volume.
The mix can impact our perception. For example a song whose vocal level is much louder than the instruments versus one where the vocal is quieter might be perceived differently. This is also related to dynamics. Similarly, if one song has a lot of reverb and another is one dry, your perception of loudness might change due to the difference in spatial perception.
Also because of this, is can also be hard to actually set to songs to be “The same volume” without an accurate LUFS meter to do so.
(I’m an audio engineer).
An IT guy at work explained this to me last week! Basically the volume at which they are recorded/how they are mixed are different, so if you have your volume at 10 for song A, song B will sound louder/quieter because they were recorded different.
2 main things. 1, the amount of limiting/compression. Compression (and limiting, which is the same as compression, just more extreme) is essentially done by making the loud parts of music quiet, so you can make the quiet parts loud. That is, there is a defined peak loudness that a sound can have. If we take the loudest parts of the sound and smash them down, we can raise the overall loudness of the sound. Imagine recording a gunshot. The very first few milliseconds of the recorded sound are massive, but the rest of the sound (99% of the sound) is much smaller. If we take those first few milliseconds and squish them down, we can raise the entire sound wave.
Next: Perceived loudness vs actual loudness. By limiting the peaks, we’re bringing up the rest of the signal. Even though we have a defined peak (in digital audio there are only so many bits in a sample), we can make it sound louder. If you look at a waveform of a song that hasn’t been limited, it has lots of peaks and troughs of varying magnitudes. If you look at the waveform of a mastered (heavily limited) song, it looks like a sausage. The songs are both the same loudness, but the squished one sounds louder.
Hope this helps. Source: multiple Grammy nominated recording engineer.
Volume is not the same as loudness. There’s several ways to measure sound levels, peak measurements deal with the loudest points, and then there are special algorithms that measure average levels, which are much more accurate at measuring loudness. You can have the same volume playing two different source materials which have been processed differently, and you’ll hear them having different loudness, despite the volume in your amplifiers being the same.
[Perception of Loudness](http://www.physics.mcgill.ca/~guymoore/ph224/notes/lecture13.pdf)
The frequency of a sound impacts its perceived loudness. Source: audiologist
* If one song has loud peaks every now and then, and another song has loud peaks all the time, the second song will seem louder even though the peaks of each song are the same level.
* Producers use a technique called “audio compression” to do this.
* Also TV and Radio stations use it too. They use it to make songs and commercials easier to hear in noisy environments.
Imagine two recordings of the same song: in the first, the singer was sitting right in front of the microphone; in the second, the singer stood 20 feet away from the microphone.
If played back at the same volume, which recording do you think would be louder?
The point is that the producer of any music has a lot of influence over how “loud” music will sound when you replay it. They can influence loudness of the recording you replay in any number of ways. Your volume setting has no bearing on their recording techniques or post-recording changes (usually with software) to the recording before it was delivered to you.
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