I'm working on an audio circuit that is really space limited. I purchased miniature 12MM 8 ohm speakers from "no name" brand from aliexpress, these speakers don't have a datasheet.
When I activated the circuit the sound is really low- even though the voltage on the speaker is 2V~3V.
I would like to purchase another set of speakers from a know brand similar to the following: https://www.digikey.com/product-detail/en/cui-inc/CDM-12008/102-2494-ND/2791824
Does anyone have experience with speakers and can tell me if such a speaker can produce a sound that will be loud enough to be heard coherently from a distance of 1-2 meters?
Difficult question to answer.
A speaker driver usually has an SPL rating, this is a A weighted sound pressure level at a distance of 1 meter with usually 1 khz at 1 watt going through the speaker.
What your interested in is max pressure, even drivers with datasheets dont allways quote this, I'm afraid trial and error is the best way, and you get what you pay for.
You forgot to tell us the important frequency the tiny speaker (squeaker) is playing. The datasheet for the CDM-12008 shows that it does not produce sounds below 1kHz properly. 2V RMS into its 8 ohms is a power of only 0.5W and the graph on its datasheet shows 1W/1m so your sound level at 1m will be 67dB to 72dB at some fairly high frequencies.