Hi Guys
To be clear, the lab sub is similar to a BT-7 except for the driver arrangement, one finds there is only so much of a given horn can be put in a given box ha-ha.
I had settled on that generic “snail” shape on an earlier box, the TPL-3 as it required the least bending.
On the picture of the bt-7, the white pipes were for a forced air cooling system which all but eliminated power compression. That fan ran off of some amount of amplifiers power so it’s speed went up and down with the signal.
I went back and looked in an old file and found a “possible group project” post on 1-1-2002. At that point it was just getting started, no drivers yet. If McJerry is monitoring, he might be able to find out when he made the samples
The project came about when some one here on PSW suggested a group build of some W bins and a following discussion of drivers.
At that time, there was some major folk lore surrounding the driver parameters needed for a given horn.
I guess you could say the lead up went this way.
I have built electronic things and loudspeakers my whole life so I relate to the diy’r, I have made a lot of cabinets and sawdust.
After giving up hopes of being in a band and then the speaker business and then doing electronic repairs for years etc I got a good job in 1978 at Intersonics inc.
I worked for 18 years at Intersonics inc, a NASA experimental hardware contractor and they needed a lot of hats filled when I started.
My bosses were an old English acoustician and a Physicist from Fermi labs and former physics teacher.
It was a great opportunity for me, I waved my hands and drew pictures and they would tell me what I was talking about. I see things working physically my mind, not in math.
Anyway, I was able to make some large improvements in the acoustic levitation transducers and systems they used so the owner gave me some latitude.
I had the idea for the Servodrive speaker on an airplane ride back from Huntsville.
After number #3 sounded good enough to bring in, Roy the president (being a hifi buff) said I could pursue a speaker business on the side as long as it only cost heat and lights.
Maybe 10 years later, the company had grown, we had flown hardware on a couple sounding rocket and two shuttle flights. I had one foot in the Speaker division and one foot on the NASA side. I had a really good mathematician named Dan Riordan assigned to help me on the NASA side and I posed that I needed a way to model sound traveling though a passage which will be defined and through a temperature gradient.
In these systems the sound source won’t last long if exposed to the 1500 degree C heat so it has to travel down a passageway to get into the furnace.
I should explain, the whole point of acoustic levitation is that there is no container, at very high temperatures, one runs out of materials that you can use as a “cup” that doesn’t cause nucleation or impurities.
Having secondary purposes in mind, I asked that it could also be driven by a set of T&S parameters “like a loudspeaker”.
Thus after considerable work on his part and by dumping the temperature gradient and doodling dimensions, I had a tool which could model a given horn’s response, ah….even a motor driven bass horn.
I used that and a couple others of Dan’s mathcad programs to design the BT-7 and others and when the lab sub project came to be, I thought hey, I’ll use these programs to make something powerful with normal drivers.
So, when somebody talks about indirect benefit from the space program, well the Lab sub alignment is an unexpected example.
At one point I had to decide if I was going to go into payload specialist training or stay and focus on the speaker business. Between being sure I would be plagued by nausea in zero G and the speaker biz growing, I passed on the Astronaut training.
Anyway, it wouldn’t have worked out as the first shuttle disaster ended our flight hardware contracts, no one got to go past the vomit comet training and it had that name for a real reason..
Man, I’m feeling old now.
Best,
Tom Danley
Author
Topic: Why did PSW copy PK's bass bin? (Read 28599 times)