If I increase voltage input on audio amp, will the volume be able to get louder?

I'm planning on building a portable speaker/boombox and I was looking up some build videos and saw people having a voltmeter built into their speakers and when they increased the volume, voltage started dropping. The audio amplifier I was planning on buying stated that it can handle DC power 8-25v. So my question is, when I increase the voltage input, will the output volume be louder or what will it change, or does the volume rely on the speakers I'm using? Or will the volume rely on the batteries I'm using?

Part list:

-TDA7492P 25W+25W Audio Amplifier with Bluetooth
https://www.banggood.com/TDA7492P-50W50W-Wireless-Bluetooth-4_0-Audio-Receiver-Digital-Amplifier-Board-p-1003047.html

-Micro USB breakout
https://www.banggood.com/CJMCU-Micro-USB-Interface-Board-Power-switch-interface-p-986085.html?rmmds=search

-DC Step-up Module
https://www.banggood.com/DC-Boost-Converter-2A-Power-Supply-Module-2V-24V-To-5V-28V-Adjustable-Regulator-Board-p-1100757.html

-USB Charging module
https://www.banggood.com/USB-Lithium-Battery-Charger-Module-Board-With-Charging-And-Protection-p-924048.html?rmmds=search

-18650 Rechargeable batteries x2
https://www.banggood.com/2PCS-ICR18650-26F-2600mAh-3_6v-Rechargeable-Li-ion-Battery-p-915708.html?rmmds=search

- 2x Visaton FR-13 30w(RMS) full-range speakers
http://www.visaton.com/en/industrie/breitband/fr13_4.html

- LED On/Off switch
https://www.banggood.com/12V-16mm-Angel-Eye-Metal-illuminated-LED-Push-Button-Switch-Car-Dash-p-965911.html

Also if anyone could check if these parts work together then it would be appreciated.
NB! I'm new to this so if my questions sound dumb then don't judge :)

rickharris2 months ago

Increasing the power supply voltage to your amplifier will increase the wattage of the amplifier and the volume of the system. I do not suggest using a voltage higher than the amplifier's maximum rating. As for the speakers - their volume is determined by their design. Speaker sensitivity ( the efficiency at which they convert electrical power into actual sound) is the key specification. A speaker with a 96 dB rating will be 6dB louder than a speaker with 90 dB sensitivity rating when hooked to the same amplifier. 6 dB may not sound like much but it sounds like a lot in most speakers. To get maximum volume you can increase the power supply voltage and use high sensitivity speakers.