I had the good fortune to find a pair of Tru-sonic woofers in an old theater last week. They appeared to be from the original installation and I was able to personally remove them.
I have found some historical imformation on these drivers, but have not been able to locate any information about the performance of them. They were mounted in Altec VOT enclosures and I am guessing they may be similar to a Altec 515.

I was wondering if they were a good fit for a new speaker project for the house. (I have a pair of Altec 311 horns with no home) Anybody here worked with these speakers before? Do they need to be horn loaded? What type of low frequency response are they capable of?

Thanks for your suggestions,
Jeff