[Question]
  [
Given an input integer, output the volume corresponding to the value. The value will always be in the range \$[0,100]\$. 
## Examples
If the input \$=0\$:
```
 _/|
|  |\/
|_ |/\
  \|
```
If the input \$>0\$ and \$<33\$:
```
 _/|
|  |\
|_ |/
  \|
```
If the input \$\ge33\$ and \$<66\$:
```
 _/| \
|  |\ \
|_ |/ /
  \| /
```
If the input \$\ge66\$, \$\le100\$:
```
 _/| \ \
|  |\ \ \
|_ |/ / /
  \| / /
```
## Rules
* Input/output can be given by [any convenient method](http://meta.codegolf.stackexchange.com/q/2447/42963).
* You can print it to STDOUT or return it as a function result.
* Either a full program or a function are acceptable.
* Any amount of extraneous whitespace is permitted, provided the characters line up appropriately.
* [Standard loopholes](http://meta.codegolf.stackexchange.com/q/1061/42963) are forbidden.
* This is [code-golf](/questions/tagged/code-golf "show questions tagged 'code-golf'") so all usual golfing rules apply, and the shortest code (in bytes) wins.
  
[Answer]
# JavaScript (ES6), 98 bytes
```
n=>` _/|2
|  |\\0
|_ |/1
  \\|3`.replace(/\d/g,k=>n?(k&1?' /':' \\').repeat(n/33^n>98):['/\\'[k]])
```
[Try it online!](https://tio.run/##dcoxDoIwFADQvaf4k@2PSgtNiJIAB6EIDRaikJYAcerdK44OzO@99Uev3fKat6t1TxP6PNi8aKHhPiEewCsliG/A85gAKOVlGy1mnnRnGFdPPlzGvLAlG09xSYHTjO6J4u8YvTHLpXzY4n7DrKJ8l2qsawyds6ubTDS5gfVMIMAZqLIUyb/IBI9EHkmaHkksBGL4Ag "JavaScript (Node.js) – Try It Online")
### How?
We use the following template:
```
 _/|2
|  |\0
|_ |/1
  \|3
```
If \$n=0\$ (volume muted):
* \$0\$ is replaced with `/` and \$1\$ is replaced with `\`
* the other digits are removed
If \$n\neq 0\$:
* odd digits are replaced with the string `" /"` repeated \$k\$ times
* even digits are replaced with the string `" \"` repeated \$k\$ times
where \$k\$ is defined as:
$$k=\cases{\left\lfloor n/33\right\rfloor&\text{$n<99$}\\
2&\text{$n\ge 99$}
}$$
[Answer]
# [05AB1E](https://github.com/Adriandmen/05AB1E/wiki/Commands), ~~65~~ 64 [bytes](https://github.com/Adriandmen/05AB1E/wiki/Codepage)
```
„ /SõD‚„\ Â‚D4δ∍D)T•4aÖ™é•“| 0\
1/“ÅвJrI33÷IĀ+©è‡∊'_1•uтÄ•22в®è‚ǝ
```
When I started I thought I would be able to make this pretty short with the approach I had in mind, but it had some annoying edge cases to fix.. Can definitely be golfed, though. Will take another look later on.
[Try it online](https://tio.run/##yy9OTMpM/f//UcM8Bf3gw1tdHjXMArJjFA43AVkuJue2POroddEMedSwyCTx8LRHLYsOrwSyHzXMqVEwiOEy1AeyDrde2ORV5GlsfHi755EG7UMrD6941LDwUUeXerwhUK1@CNAQoJampgubDq0Dyc06Pvf/fwMA) or [verify some more test cases](https://tio.run/##yy9OTMpM/V@m5JlXUFpipaBkX6nDpeRfWgLh6fx/1DBPQT/48FaXRw2zgOwYhcNNQJaLybktjzp6XTRDHjUsMkk8PO1Ry6LDK4HsRw1zahQMYrgM9YGsw60XNnkVVRobH95eeaRB@9DKwyseNSx81NGlHm8IVKsfAjQEqKWp6cKmQ@tAcrOOz/2vc2ib/f9oAx1DHWMjHWNjHWMTHTNTHTMzHTNzHUsLHUtLHUMDg1gA).
**Explanation:**
```
„ /              # Push string " /"
   S             # Convert it to a list of characters: [" ","/"]
õD‚              # Push an empty string "", duplicate it, and pair them together: ["",""]
„\               # Push string "\ "
   Â             # Bifurcate it (shorter for duplicate and reverse copy)
    ‚            # Pair them together: ["\ ","\ "]
D                # Duplicate it
 4δ∍             # Extend both inner strings to size 4: ["\ \ ","\ \ "]
D                # Duplicate it
)                # Wrap all lists on the stack into a list:
                 #  [[" ","/"],["",""],["\ ","\ "],["\ \ ","\ \ "],["\ \ ","\ \ "]]
T                # Push 10
•4aÖ™é•          # Push compressed integer 17523821317
“| 0\
1/“              # Push string "| 0\\n1/"
   Åв            # Convert the integer to custom base-"| 0\\n1/" 
     J           # And join these characters together to a single string:
                 #  "  /| 1\n
                 #   |  |\0"
r                # Reverse the items on the stack (list, 10, string to string, 10, list)
 I33÷            # Push the input, and integer-divide it by 33
     IĀ          # Push the input again, and truthy it (0 if 0; else 1)
       +         # And add them together (0→0; 1..32→1; 33..65→2; 66..98→3; 98..100→4)
        ©        # Store it in variable `®` (without popping)
         è       # And index it into the list we created at the start
          ‡      # Then transliterate the ["1","0"] of 10 to the strings in this pair
∊                # Now vertically mirror the entire string
                 #  (i.e. "  /|  \n
                 #         |  |\/" becomes:
                 #   "  /|  \n
                 #    |  |\/\n
                 #    |  |/\\n
                 #      \|  "
    •/Tδ•        # Push compressed integer 7095187
         ₂в      # Converted to base-26 as list: [15,13,17,21,21]
           ®     # Push variable `®` again
            è    # Index it into this list
   1         ‚   # Pair it with a leading 1
 '_           ǝ '# And insert a "_" at those 0-based positions inside the string
                 # (after which the result is output implicitly)
```
[See this 05AB1E tips of mine (section *How to compress large integers?* and *How to compress integer lists?*)](https://codegolf.stackexchange.com/a/166851/52210) to understand why `•4aÖ™é•` is `17523821317`; `•/Tδ•` is `7095187`, and `•/Tδ•₂в` is `[15,13,17,21,21]`.
[Answer]
# [Python 2](https://docs.python.org/2/), ~~111~~ ~~101~~ 90 bytes
```
n=input()
for s in'\ _/|','\|  |\/','/|_ |/\\','/  \|':print s[1:6+0**n],s[:n>32],s[:n/66]
```
[Try it online!](https://tio.run/##Jc2xCsIwEIDh/Z7i6BKthaQJ3lCoizr7AE3pIBWzXEMbQeHePba6fcMPf/yk58Q2n2@XazsXRZG5DRxfabeHxzTjgoGVx0GLqpQXRPF6lZYBRXu/EdGLauIcOOHS1Q0dTFlyXy1dwydn/9BEff41sE5gfI933J4lZQPOgnNARyCC2pgv "Python 2 – Try It Online")
-11 bytes, thanks to xnor
[Answer]
# [Lua](https://www.lua.org/), ~~308 259 246 242 219~~ 180 bytes
```
i=io.read("*n")
print(i<1 and[[ _/|
|  |\/
|_ |/\
  \|]]or i<33 and[[ _/|
|  |\
|_ |/
  \|]]or i<66 and[[ _/| \
|  |\ \
|_ |/ /
  \| /]]or[[ _/| \ \
|  |\ \ \
|_ |/ / /
  \| / /]])
```
[Try it online!](https://tio.run/##XcqxCoAgFAXQ3a@4NGVDEoFTfUlGCDU8CA2p7f27EVZGZz7rYWOknnwdFjuXReUKKbZAbi@pa2DdPAyYFAsG2CjBE1gZARgeRx9AXdv@V0rfo3U@MGnhfkgT6rpPySm3N15Vxqj1CQ "Lua – Try It Online")
New to code golf and coding in general.
  
Thanks to all comments for their help!
[Answer]
# [PowerShell](https://github.com/TryItOnline/TioSetup/wiki/Powershell), 113 bytes
```
param($n)' _/|'+($y=' \'*($x=($n-ge33)+($n-ge66)))
'|  |\'+($y,'/')[!$n]
'|_ |/'+(($z=' /'*$x),'\')[!$n]
"  \|$z"
```
[Try it online!](https://tio.run/##NYzNCsIwEITveYq1LG62rUQM5JYnMVJ6SPVQa6kH@xOfPYYULzPDN8OMr4@f3g/f9xE7u4k4tlP7lDgwQaMCVRIXS@ColDjbxE93rzVXezKGmQUFgODytCZFfD3gcEu0gaASlbimB0UlzlyT@/cFgAu4FlF8hThiB@es@rKbzmZM/AE "PowerShell – Try It Online")
[Answer]
# [Perl 5](https://www.perl.org/) (`-p`), 86 bytes
inspired from @Arnauld's solution
```
$_=' _/|3
|  |\\1
|_ |/0
  \|2'=~s,\d,$_?" $&"x($_/33-$_/99):$&<2&&$&^1,ger;y;0213;//\
```
[Try it online!](https://tio.run/##DczfCoIwFIDx@/MUBxmzYLY/B0e2pCfoDUYjSEQQHepFwejRW958v7svdstY58xCW2KQiSAhJu81pIBJKkD0yZTtdxX@JVi4Fch48T6wIImqvU1zvDB@NZwz/tCi7xb3ccpoclL6nBVoIANEYGuwFpozaKV@c9yGeVpzNT5jru71SemdYdq6ffAH "Perl 5 – Try It Online")
[Answer]
# [PowerShell](https://github.com/TryItOnline/TioSetup/wiki/Powershell), ~~94~~ 92 bytes
```
param($n)33,66-le$n|%{$y+=' \';$z+=' /'}
" _/|$y
|  |\$y"+'/'*!$n
"|_ |/$z"+'\'*!$n
"  \|$z"
```
[Try it online!](https://tio.run/##LcjBCsIwEITh@z7FGkajVokYyEX6JoHSQ4qHGEs9SNrts8davcw/fP3zHYbXPcRY0NUTlb4d2sce6WDtyblzDEiynZCrWrPXN4zfY/RMihsjyCTM4pFVpY0@bpBIScNiMC7i/8LsZYFCM9EOHV/Wtddf7Brnygc "PowerShell – Try It Online")
[Answer]
# [Canvas](https://github.com/dzaima/Canvas), ~~32~~ ~~27~~ 26 [bytes](https://github.com/dzaima/Canvas/blob/master/files/chartable.md)
```
┤＃Mi‾‟⁸？⁸‾｛÷ｕ２ｍ２＼×＋］ ¶/＋｝═
```
[Try it here!](https://dzaima.github.io/Canvas/?u=JXUyNTI0JXVGRjAzTWkldTIwM0UldTIwMUYldTIwNzgldUZGMUYldTIwNzgldTIwM0UldUZGNUIlRjcldUZGNTUldUZGMTIldUZGNEQldUZGMTIldUZGM0MlRDcldUZGMEIldUZGM0QlMjAlQjYvJXVGRjBCJXVGRjVEJXUyNTUw,i=MzM_,v=8)
[Answer]
# [Charcoal](https://github.com/somebody1234/Charcoal), 40 bytes
```
ＮθＦ AＦ›θ℅ι \Ｃ¹¦¹⸿\Ｆ¬θ/‖Ｍ↓⸿←Ｐ↑⁴←↖¹←_↑² _/
```
[Try it online!](https://tio.run/##XY7NCsIwEITvPsWSUwIVW/FUT6Iggq1F8FYotaYYiElc0opPH5vWn@Jtdr@Z2a2uJVa6lM7tlGls2tzOHOmdLSe1RqAEVoRBL7fIS@tZAAe8CFVKKhhjkKFQtjPmOelSa22eNAog6vSb5DigviXVtmv/pmYeHHkteWUTgaiRxhv9UOO0tyS65TTe89r6oZFWmB7HJxPA4t@QfZifx7/Ew4IUZOwKYP67B4X/ybkoDN20lS8 "Charcoal – Try It Online") Link is to verbose version of code. Explanation:
```
Ｎθ
```
Input the volume.
```
Ｆ AＦ›θ℅ι \
```
Output a space and a `\` for each character ordinal in space and `A` that the volume is greater than. In other words, output once for inputs of 33 or more and twice for inputs of 66 or more.
```
Ｃ¹¦¹
```
Copy the `\`s one square diagonally.
```
⸿\
```
Output an extra `\` at the start of the second line.
```
Ｆ¬θ/
```
If the volume was zero then add a `/`.
```
‖Ｍ↓
```
Reflect to complete the volume.
```
⸿←Ｐ↑⁴←↖¹←_↑² _/
```
Draw the speaker symbol.
[Answer]
# [Keg](https://github.com/JonoCode9374/Keg), `-hd` 167 bytes
```
¿:0=[` _/|\n|  |\\/\n|_ |/\\\n  \\|`|:1\!"∂[` _/|\n|  |\\\n|_ |/\n  \\|`|:\!B"∂[` _/| \\\n|  |\\ \\\n|_ |/ /\n  \\| /`|` _/| \\ \\\n|  |\\ \\ \\\n|_ |/ / /\n  \\| / /`
```
[Try it online!](https://tio.run/##y05N////0H4rA9voBIV4/ZqYvBoFhZqYGH0gI16hRj8mJiZPQSEmpiahxsowRlHpUUcTqkKYOriqGEUnhCoFsAKwQgW4WgWYagX9hBqYMlSVyIqRlAM1/P9vZvZfNyMFAA "Keg – Try It Online")
Definitely golfable by using variables and string formatting. That's what Imma go do now. Anyhow, it acts as a sort of switch statement to determine which range the volume is in and prints the corresponding string.
Nevermind. Variables only make the program longer.
[Answer]
# [Python 3](https://docs.python.org/3/), 109 bytes
```
lambda n:'\n'.join(i[:5+0**n]+(n//33*(' '+j))[:4]for i,j in zip([' _/|','|  |\\/','|_ |/\\','  \|'],'\\\//'))
```
[Try it online!](https://tio.run/##FYtBCoMwEADvfcXeNolLE5uaQ6AvcUUsJTRSVxEvLfm71dvAzCzf7T2L39OD988wPV8DSEQWvI5zFpXb2FTOGOkqJdZ6bxQCVqPWbbx3aV4h0whZ4JcX1SL0tiBhASjM9qQeimU@CIALdoR8CIta7@cs5@qoJn8j7yk0FALVzsULLGuWTSUlR/oH "Python 3 – Try It Online")
[Answer]
# [Lua](https://www.lua.org/), 196 bytes
```
i=tonumber(io.read())
t=[[ _/|%s
|  |\%s
|_ |/%s
  \|%s]]
t=(i==0 and t:format("","/","\\","")) or t
while i>=33 do t=t:format(" \\%s"," \\%s"," /%s"," /%s");i=i-34 end
t=t:gsub("%%s","")
print(t)
```
[Try it online!](https://tio.run/##RYxBCsIwEEX3OcUQKCSgRqgoKPEiTSktiTrQJpJOcZO7x9SFXcx/8Hl/xqXPGTUFv0yDiwLDIbreCikZ6aaBTqVqZgkgmZUdJFUIYErdtsURqPURem@Bro8Qp54E5zuuyhlTgksJIQKxzwtHB3jXdQ02AOnNB1OeF/dPtUHeUOO@PoHzlq2j57wMglc/g0v2juhJkMz5fPkC "Lua – Try It Online")
A bit shorter (below 200) than the [other Lua answer](https://codegolf.stackexchange.com/a/195519/63068).
]