Anyone know who, or what organization, determined the woofer sizes most commonly used in consumer-level gear, in other words 4", 5.25", 6.5", 8", 10", 12" and 15"?
Or did these sizes just evolve "organically" with no official intervention?
Or did these sizes just evolve "organically" with no official intervention?
Hi,
They evolved in your terms, however there were lots
of ellipticals for single full range drivers in the past.
rgds, sreten.
They evolved in your terms, however there were lots
of ellipticals for single full range drivers in the past.
rgds, sreten.
If you look at the cone area starting at a 4" and go up to an 18", you'll find the cone area ratio for the next size up averages out very close to the golden section number Phi (1.618).
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These sizes were standardized in the early radio days. I think that the EIA was involved at one time. I also agree that they approximately hit constant percentage steps in area growth. Note that there is some ambiguity in measurement as well. I was always told to measure round woofers across the diameter and pincushion or square across the short dimension rather than the diagonal. That led to odd circumstances such as a 5" round midrange using the same cone as a 4 1/2" pincushion.
Different makers also made their own odd sizes and favorites. For automotive the Europeans like 4 x 6 and 4" (100mm). Detroit liked 6 x 9 and 5 x 7, but Ford had a different size 5 x 7.
Different makers also made their own odd sizes and favorites. For automotive the Europeans like 4 x 6 and 4" (100mm). Detroit liked 6 x 9 and 5 x 7, but Ford had a different size 5 x 7.
Thanks everyone for the replies! Sorry I took so long to return - work-related issues kept me busy.
The golden section number concept & spreadsheet w/ratios are interesting (for some reason the TV show Ancient Aliens came to mind after reading those posts 😉 😀).
BTW seven inch woofers seem to be appearing more often, though I first saw this back in 1998 when I was shopping for some new speakers: Boston Acoustics offered the CR9 with an 8" woofer, which I bought, and the nearly identical smaller CR8 with a 7" woofer and same tweeter but smaller enclosure (why "CR8" with the seven incher? Hmm).
The golden section number concept & spreadsheet w/ratios are interesting (for some reason the TV show Ancient Aliens came to mind after reading those posts 😉 😀).
Yep I've definitely noticed that issue over the years. Especially with modern subwoofer drivers i.e. the spec sheet says "ten inch" but the cone looks more like @8" because of a huge surround.
BTW seven inch woofers seem to be appearing more often, though I first saw this back in 1998 when I was shopping for some new speakers: Boston Acoustics offered the CR9 with an 8" woofer, which I bought, and the nearly identical smaller CR8 with a 7" woofer and same tweeter but smaller enclosure (why "CR8" with the seven incher? Hmm).
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