How long have D.I been around?

[scott]

Does anybody know how long d i boxes have been around for ? Like late 70's ? or much much earlier. Reason I ask is, I always had the idea in my head that they were a child of the eighties, but the other day, listining to the Pendulm record by credence clearwater revival and thinking how dry the sounds all are . Bass might have been di no? How long have you older heads been using them in the studio ? Were they originally designed for live usage or studio. Also is it possible to 're-align', in the analog domain, your direct and microphone signals. I mean how necessary is it anyway.

A shit load of questions I know but feel free to generalise on the topic of di's (like, got any favorite types)

[Chinagraf]

I don't know when di's were first used, but recording to analog tape, you delay the dry signal to get it in phase. It's about 4milliseconds per foot that the mic is away from the speaker. You don't notice the 4 msec delay to the dry signal.

[rick]

like most things with the guitar and studios
les paul was doingn it in the .. 1950s

[ottowr]

I don't know when di's were first used, but recording to analog tape, you delay the dry signal to get it in phase. It's about 4milliseconds per foot that the mic is away from the speaker. You don't notice the 4 msec delay to the dry signal.

I think you'll find it's closer to 0.9 milliseconds per foot. (or to be exact, 0.88762648677436534706195632877685 milliseconds per foot)

At 20 degrees C the speed of sound is 343.4 m/s (= 1126.6 ft/s = 1236 km/h = 768.2 mph = 667.1 knots).

[Chinagraf]

Sorry, my mistake - I usually use around 4 msec, but I have the mic about 4 feet off the amp. So yes, more like 1 msec a foot. Either that or my studio is 100 decgrees C.
Thanks for pointing that out Otto