Pretty much everything about the science of sound was figured out in the 1930s — with the exception of digital of course.
If you're not an audiophile, you may have not heard this before, but it's fun to think about.
Picture the stereotypical NASA ground control scene. You've got the absolute brightest minds and best scientists all hired and gathered together to make a science dream team. If astronauts get into trouble like they did in the Apollo 13 mission, they at least have the comfort of knowing the cream of the engineering crop will be crafting a solution for them on the ground.
This type of environment existed in the '30s at Bell Labs — minus the space travel, of course. Different type of science but a similar best-of-the-best approach to solving scientific problems. Back then, audio reproduction and transmission over radio was the "space race." Bell hosted the sharpest scientists in their labs, scientists who eventually discovered and demonstrated most of what we know today about audio. In those days, they could devote all attention to a realm of science we now tend of take for granted.
And so when you hear about revolutionary approaches to speakers for instance, you can also get your grain of salt ready because chances are it's not revolutionary at all.
One perfect example of this is the tapped horn subwoofer. In recent years, a guy named Tom Danley has taken this ancient subwoofer design and created a brand (Danley Sound Labs) and a name for himself around reintroducing it into the home theater and pro markets.
I love a good tapped horn sub, and I've built quite a few — even a couple commissioned by a Deep House DJ in Denver.
Briefly, the tapped horn takes advantage of something I discussed last week: "phase add." I know you all understand that sound comes off the front of a speaker, but since it's a back and forth moving cone, it also generates the same waves out the back of it. This usually goes into a box and dissipates or acts like a spring for the speaker. However, in a tapped horn, the front wave is sent around a relatively long distance in the box until it matches the back wave, doubling it up.
This means the tapped horn can be one of if not the loudest type of subwoofer. Recently it's seen a lot of action in car system tournaments (oh yes — they're a thing). When I had one I had built in my home system a few years ago, it was the fourth horn in a 4-way, quad-amped, two-channel system. Even though I attended quite a few punk rock shows in Florida in the '90s, I consider that setup to be more responsible for any hearing loss I may have developed in my life.
Back to the tapped horn though, it's a solid idea that produces real results. Just one of the many "new" designs in audio that really aren't. Those early 20th-century scientists were serious badasses!