Acoustic engineer

So in our second week of the speaker project we had the benefit of learning about acoustics and speakers. Research acoustic engineer Martin Møller from B&O, gave a small lecture about accoustics and speakers in general and about how tweeters and drivers work.

Here’s a recap of what we picked up from the lecture:

For starters we learned about the frequencies the human ear can hear and which frequencies diffrent types of sounds are played in. Mr. Møller explained this point easily by dividing the hearing spectrum into three instruments: “A triangle, violin and a contrabass”. The low frequencies ranging from 60 Hz – 250 Hz he fittingly labeled as “contrabass”. The middle ones ranging from 250 Hz – 2.000 Hz as “violin” and the high frequencies ranging from 2.000 Hz – 20.000 Hz as “triangle”

Next we learned about the limitations of speaker units in terms of the actual size of the units, hence the importance of crossover networks. As we already knew, speaker units come in different sizes, the smallest unit in a complete loudspeaker called tweeters, bigger units called drivers and the largest units often referred to as woofers. Mr. Møller taught us that that tweeters are better suited for playing the high frequencies and that the drivers are better suited for the middle to low frequencies. This is were the crossover network comes in handy. By using the crossover, it is possible to assign different speaker units to play only a specified range of frequencies. By doing so, it is possible to utilize more of the potential of the individual speaker units.

To round things off we learned why a cabinet is needed for a speaker to perform, and why the volume of the cabinet is an important aspect of creating good sounding speakers. The cabinet works as an enclosure to prevent the sound waves generated by the rearward facing surface of the speaker unit.