RCA 64-A Speaker 8" ( MI-4410 )

RCA 64-A是RCA於1935推出的鑑聽揚聲器系統，當年是由RCA音響研究部門的主管Dr. Herry F Olson負責設計，它主要是初期FM電台及專業錄音室作為鑑聽揚聲器之用，另外它更是美國音響史上最早出現的迷宮接合號角音箱設計的鼻祖。 (文)資料來源http://www.review33.com

Just finished a restoration of these, really just a repaint. Paint is a high build lacquer, just like original, and was computer matched to the correct color. Grill cloth is original. All parts are original except the flat panel portion of the removable front grill (I still have the original piece, but it was deemed too far gone to restore by my woodworker. I'll include it if you want it). Everything else was solid and dry, requiring only sanding, priming, and finish painting. Text on the back was printed directly to the paint (i.e. it's not a sticker or decal). Paint scheme is correct and authentic to the original.

Not sure if there'll be any interest in something as rare as these. We'll see.

So here's what they are: Introduced in about 1936 or 1937, the model 64-A speaker was RCA's top of the line studio monitor speaker for highest quality, most demanding applications like recording studios and radio stations. Never available as a consumer product. These cabinets would have originally been equipped with a model MI-4466 8" speaker that was a marvel for its time (and still would be, if anyone would make them). Featuring an 8 inch cone and field coil magnet, the MI-4466 had a split voice coil. Two voice coils on the same former, one small light aluminum coil for the high frequencies, and a larger coil for the mid and low frequencies. A small compliance between the coils allowed them to move separately. Very clever and effective way to extend the frequency response of a single driver loudspeaker (much better approach than a cheap 'whizzer' cone). Later (1940's) RCA models of similar specification were the MI-4411 (field coil) and MI-4410 (permanent magnet). Highly regarded and hard to find. I've heard these old drivers referred to as 'Lowther killers'. Sadly, this auction is for the cabinets only, as I don't have the original speakers for them.

The cabinets, too, are a marvel of engineering, credited to Harry Olson of RCA. They're a back horn loaded design. Flare rate is around 40Hz, I'd guess, and the length of the horn is 8 feet or so. These make an Acousta look kind of silly. Each cabinet measures about 18 1/2" deep x 28" wide x 33 1/4" high and weighs about 80lbs. Very solidly made.

If you're fortunate enough to have access to the original RCA speakers (MI-4466), that's great. I could never find any available for sale (they're out there, they're just not for sale). You may have to get resourceful. An RCA PL52 theater speaker unit should fit right in, since it has the same front mounting flange. The PL52 doesn't have the split voice coil, though, and has a larger field coil mechanism than the MI-4466. Next option would be a later (1940's) version, either the MI-4411 or MI-4410. I may actually have a single MI-4410 available shortly, but it isn't part of this auction. Either of these are probably closest in spirit and execution to the original (they both have the split voice coil), but would require an adapter to bolt in as they have a different mounting flange. This would be very easy to do, in fact I have a pair of blank adapter boards I had made with the thought that I'd eventually need them. Winning bidder can have them at no extra charge if desired.

After all that, most of us are never going to find the original drivers for these, so the best option is to use something else altogether. Modern drivers by Fostex, Supravox, Lowther or others would work great in these. Any driver designed for rear horn loading. Or vintage drivers by Altec, JBL, Western Electric, Stephens, Norelco, Philips, and many others. Or get a pair of old field coil drivers. Lots of choices. Lots of fun.

Some of you may have seen my progress on the restoration of these cabinets detailed on the Audio Asylum High Efficiency forum. If you haven't, take a look. There's lots of before, during, and after photos. I undertook the restoration of these cabinets primarily for two reasons: 1.) because I had them, and 2.) I was restoring a pair of RCA LC-1A cabinets at the same time. It was just easier to do it all at once. The LC-1A cabinets and the 64-A cabinets are all the same paint colors.

While local pick up is encouraged, the cabinets can and should be crated for shipping. Domestic shipping will be by freight carrier. Overseas shipping available airport to airport via Schenker. Rates will have to be figured out if you're serious, but probably several hundred dollars. Figure a 250lb crate, 4' x 4' x 3' and you should get pretty close. Please don't ask for a shipping quote to every corner of the globe. You have the size and weight, the starting and ending locations, and a computer. You can figure it out. I have confidence in you.

Anyway, just throwing these out there for everyone's consideration. Contact me if you have any questions.

Please see my other auctions for more vintage hi-fi and DIY electronics stuff this week. Thanks for looking.

勵磁 RCA MI-4411



天然磁、勵磁 RCA MI-4411