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I'm trying for a couple of days now how to get a good volume out of a small speaker. My reference is e.g. an iPhone internal speaker which has a good loudness (up to 100dB) in the higher and middle frequencies. Is this just a result of the speaker housing or are there more important aspects to focus to get this sound clarity?

Actually I tried a lot of speakers which are bigger than iPhone internal ones but I can't get an acceptable loudness. Only if I work with single frequencies (like a piezo beep) — but if there are more complex sounds, e.g. a bell, it's very quiet.

Compared the same "more complex" sound on my iPhone speaker it sounds fine.

So the question is: What aspects are important to get a good bright sound with a small speaker in a small housing (e.g. a Raspberry Pi box)?

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  • \$\begingroup\$ Maybe the iPhone speaker sacrifices purity of sound for increased volume. What sort of enclosure did you mount your speakers in? \$\endgroup\$
    – Andy aka
    Oct 8, 2014 at 14:38
  • \$\begingroup\$ @Andyaka There's no enclosure yet because I'll need to place a speaker into a small housing and I don't know which parameters I can influence to get a good volume. (Target: >= 75dB ~2kHz-6kHz) \$\endgroup\$
    – Bernhard
    Oct 8, 2014 at 16:33

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Enclosures make a huge difference to speaker loudness. The one in the iPhone is small, but you can bet it's optimized for clarity and loudness of middle-to-high frequency audio.

For your goals (bright + small) choose a driver with high efficiency at 1kHz and above. Aim for over 100 dB/W/m if you can.

If your enclosure size is fixed, then do what you must. Otherwise note that larger enclosures generally provide better low frequency response, and harder enclosure materials will help with high frequencies. Use a sealed (no holes or "ports") enclosure unless you want to learn all about Thiele-Small parameters. Sealed enclosures are easy to make and (more importantly for you) perform well for mid-to-high frequencies.

Lastly, the other key factor to obtaining a bright and loud sound is the power amplifier. Buy or build one that can put out at least as much wattage as the speaker's RMS rating. Sizing the amp is a matter of which device you'd rather start distorting first. Amplifier distortion might be pleasing to your ear (depending on context and the way the amplifier distorts), but speaker distortion rarely is.

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