Loudspeaker Sizes in RC Installations

At Model Sounds Inc., we believe in offering the best sounding RC Sound Systems. We do not believe in skimping on loudspeaker sizes as tiny loudspeakers result in, well - "tinny" sound.

The basic laws of physics demand that you can’t get a quart out of a pint pot. With small speakers you get small sound – and what I mean by “small” is tinny sound, not necessarily quiet sound. I.E. you get tinny sound from a tiny speaker, there is no way around that. And it doesn’t matter how many tiny speakers you have in series/parallel combination - you just share the total available power between them - multiple tiny speakers may be able to take more total power input, but this does not improve the frequency response at all.

The human ear peaks its sensitivity at around 2KHz. That frequency is well within the range of tiny speakers so some tiny speakers can sound very loud because that is where they peak at, or close to it. You can actually get tiny piezo transducers for alarms etc. that can produce 100db from a tiny package, but they can do so only in a very narrow band of frequencies.

If you look at the frequency response of almost all 2inch loudspeakers you will see they have a response from around 400Hz to 8KHz or so. In order to reproduce low frequency sounds you have to move a lot of air and a small diameter speaker simply does not have a large enough cone to make an adequate piston effect to move that air.

The manufacturers quoted frequency response of the 4inch speakers we sell is quoted as 100 - 14000Hz. That is a good deal better than 400Hz. While even that is not a terrific bass response, you will get significantly better quality sound from a 4inch speaker than from a 2inch one.

If your model is large enough, you can go even larger and install a 5inch or 6inch speaker. For model airplanes, of course space and weight considerations take first priority, but in general, the larger the speaker, the better it will sound.

You must also consider sensitivity - measured in dB/1W/1m. A measurement of 90dB/1W/1m means that for 1 Watt of electrical input power, the loudspeaker will produce a Sound Pressure Level (SPL) of 90dB when measured at 1m (about 39inches) on the axis of the speaker. Many small loudspeakers have sensitivities far less than that figure. e.g. some 2inch speakers have only 79dB/1W/1m. Therefore whatever the size of loudspeaker chosen, you should always strive for the highest sensitivity figure possible.