Speaker Design Project

Kevin Duncklee

EE/CS 107: Projects in Music & Science

I began the term by learning about loudspeakers by reading and through discussion. I decided to start my design with the midrange, as this is the most important area, where most of the human voice resides. I looked at a large number of drivers, in catalogs and on the web and narrowed my decision down to four:

Vifa PL11WG09 4.5” paper cone
Vifa P13WH00 5” polypropylene cone
Peerless 850108 5” paper cone
Seas CA15RLY 5.5” paper cone

I ordered two of each of these drivers from Madisound and mounted them in a 4x8’ MDF baffle.

We then conducted careful listening tests, comparing the speakers in pairs. We did tests using stored content from a CD, live audio from a direct feed, and CD audio passed through a bandpass filter to remove any sound beyond the range of the speakers. The speakers were narrowed down to the two Vifa drivers, and later I decided that I preferred the PL11WG09.

I then began looking at subwoofers and tweeters that would match the PL11. The problem with matching drivers to it is that it had a low efficiency of 85 dB. Since I couldn’t find a suitable subwoofer with that low efficiency and I didn’t want to destroy the sound by padding the woofer, I decided to bi-amp. I would put the sub on it’s own amplifier and put the midrange crossed over with the tweeter on the second.

At the same time, began designing an enclosure for the midrange. I drew up a design using parallel sides and the formulas in the Loudspeaker Design Cookbook.

Future Work

Next term, I will make the above enclosure for each mid, as well as one that is 30% larger in volume and one with non-parallel sides. I will also make a final decision on which subwoofers and tweeters to purchase for testing. After I decide on the midrange enclosure and all the drivers, I will design the overall speaker enclosure. I will also test out different methods of damping to reduce panel vibration.

Reflections

I learned a great deal in the past term, and not just about building a set of speakers. I learned how to do an analytical listening test and how important and different it is to test using a live source. In our discussions, we often went off on tangents, but it was always interesting and enlightening.

Sources

Colloms, Martin. High Performance Loudspeakers. Pentech Press, 1980.

Dickason, Vance. Loudspeaker Design Cookbook. Audio Amateur Press, 2000.

Loudspeakers, vol. 1 & 2. Journal of the Audio Engineering Society, 1953-1983.

Later work

I decided on the Vifa DX25TG-05 tweeters and constructed my final speakers. I use a Rane AC 23 active crossover and Adcom GFA-545 amps.

My current homepage