What's a good internal speaker?

[Sammy]

My computer case didn't come with a built-in PC speaker, a.k.a. internal speaker, miniature speaker, buzzer, etc. There are many names for this cute little thing. But you know what I mean - the thing that beeps inside your computer. It can sometimes drive people crazy. But it's quite useful for troubleshooting boot problems. It will emit BIOS beep codes that tell you what's wrong.

So I was thinking about adding one of these to my computer. I thought about getting a ready made one, like the one included in the ATX Control Kit by "HighSpeedPC". But I couldn't find a place to buy it in Europe, it's only available in the US. See picture below.

Since I will be ordering some other parts from Farnell, I figured why not get one of these.

What's a typical resonant frequency for a PC speakers?

What's a good SPL level?

What's the speaker supply voltage on Intel/Gigabyte motherboards?

[Sammy]

Okay, I've done my research now. The resonant frequency for piezo transducers ranges from 120 Hz up to 135 MHz. For buzzers, the typical resonant frequency, that I have found, ranges from about 2 KHz to 4.8 KHz. I have measured the voltage on the speaker pins for the front panel header of the motherboard, and it peaks at 5.02 V DC, +/- 0.05 V on startup. It then rests at about 0.04 V DC, +/- 0.01 V. I now also know it works, I won't have to enable it in BIOS.

Note: The figures above show the "ranges" of resonant frequency, not the frequency range. Piezo buzzers are monotonal, they are fixated to one frequency. While the frequency for "regular" piezo transducers may be variable. Resonant frequency refers to the frequency with highest amplitude.

I will go with the 2.3 KHz Kingstate buzzer (Farnell part number 2215080). It's rated at 5 V, and the supply voltage is rated 3 to 7 V. Hopefully it will work and make nice high pitched sounds (not too often I hope).

It's interesting how Newark stocks the above mentioned "ATX Control Kit" (Newark part number 94T9522). Newark is a subsidiary of Premiere Farnell for the US market. Most parts sold by the Newark company in US can be backordered through Farnell in Europe. But not this one. I don't really care because I can assemble these goodies on my own, I just need the parts. I'm putting this on record, as a reference, for our US visitors, so they know they can get it ready made from Newark. This type of thing is hard to come by here in Europe.