Enclosed speakers or open diaphragms? What will fit and where?

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Building your own audio system is not a simple matter – especially when you don’t have the right experience. The lucky owner of a sound system has a lot of questions and ideas to consider before getting started. One of the basic questions is whether it is better to use built-in speakers or those with open diaphragms. Check it out!

What is an enclosure actually for?

Most audio systems include an enclosure, speakers, a crossover, interconnect cables, and jacks or terminals. However, this does not mean that all audio systems are built on the same schematic. You’ll find all sorts of variations on the market – one of which is open diaphragms. To answer the question in the title of this article, it is worth to focus on technical issues first. Why do we actually need an enclosure for a loudspeaker?

The following knowledge will also be useful for DIY enthusiasts, for whom building their own devices is not an insurmountable task. Imagine that you have a bass speaker without an enclosure. After connecting the signal it turns out that despite the visible work of the membrane, the reproduced sound is barely audible. Why does this happen? The culprit is the so-called acoustic short circuit. The lack of enclosure contributes to the compression of air in the front and pumping it to the rear of the speaker – low tones spread out circularly. Because the diameter of the diaphragm is small compared to the wavelength of the low sounds, the pressure equalizes and the diaphragm does not have much to do

This issue actually applies only to woofers. In the case of midrange and treble the situation looks quite different. The wavelength of those sounds is comparable with the diaphragm diameter, so the phenomenon of acoustic short-circuit does not have much room to play. While open diaphragms have no objections to midrange and treble, bass sounds require a different, more practical approach

Acoustic short-circuit

How to deal with the phenomenon of acoustic short-circuit? It will be important to properly acoustically separate the front and back of the diaphragm. This lengthens the path between the two sides of the speaker – thus preventing acoustic short-circuit. This is where loudspeaker enclosures come into action. Only they will ensure proper reproduction of low tones. You can find all sorts of speaker enclosures on the market, but this will not be something we will discuss in detail

You have probably ever wondered why guitar amps very often lack uniform, closed back part of the cabinet. This example perfectly illustrates the discussed issue. It is not enough to enclose the speaker to allow it to work properly at limited frequency. Both the front and back of the speaker need free space to allow sound waves to move and resonate freely. While the devices currently available seem to be a given, it is worthwhile from time to time to consider their general principle of operation


It is time to summarize and answer the question asked in the topic of the article – built-in speakers or open diaphragms? Everything depends primarily on whether a given speaker will be responsible for the production of bass, midrange or treble. The last two types will do great with open diaphragms because of the comparable diameter of the speaker and the acoustic wavelength of those tones. However, when it comes to bass, the matter quickly becomes complicated. Lack of appropriate development will translate fatally into sound quality and audibility.

(photo: pixabay.com)

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