So the LG Nexus 5 speaker seems to be low volume for some people and not so much others. I spoke to @supercurio and he says that his device is as loud as a Galaxy S 4 and the volume appears normal. My device suffers from low volume. I fear that this is due to the construction process and the glue used to assemble the device may have leaked into areas which it obstructs the speaker port. It appears to be a manufacturer defect.
But, this is XDA, so rather than complain, here is a fix. We aren't just talking about a little bit of an increase though, Senior Member @Oli1122 measured a 13dB increase using this method with just one additional hole on the front and one on the rear. That's well over double sound volume!
Note: Only do this if your volume seems oddly low or risk damaging components for no reason
You will need:
Phillips #0 screwdriver
case opener tool
Performing the mod
1. Remove back panel from device (case opener tool/gitaur pick).
2. Heat up the needle with the lighter.
3. Stick needle through plastic until you feel no resistance in one of the locations shown in picture below.
4. Wait 1 second
5. Move needle around to slightly widen the hole after it loses some heat to the housing
6. Once needle has cooled, twist and remove.
7. You can remove the speaker assembly by removing four screws , then pick a new location and perform steps 2-6 on the other areas of the assembly shown in the pictures below.
8. Reassemble device.
Theory behind it:
If you ask an audiophile, they will tell you that free-air speakers are louder than sealed or ported speakers. This works because the device has an almost sealed speaker and the intended ported output of the sealed speaker chamber is much smaller than the primary speaker output.
Further testing is required
Considering this, it may benefit unaffected users to perform this modification. I intend to feature this on XDATV in two weeks. I would appreciate assistance with quantifiable measurements. So, if you perform this mod, please get a video showing your desktop's sound-level input meter with a microphone positioned at a known distance from the Nexus5 speaker (located on the left side as viewed from the front). Windows Sound Level Mixer will work just as Ubuntu or Mac's will too.
Your results may vary. If you try this, share your results and let people know if you tested before/after with a microphone, which locations you used, pictures, or if it just plain sounds louder. This issue affects several users and now at least I can watch YouTube videos comfortably now, without cupping the speaker or holding it closely outside.