Altec Model 515 (Northern Electric) - Enclosure and HF driver recommendations

[eLeakist]

I have recently acquired the subject single speaker mounted on a vintage 1/2 inch plywood cloth covered fascia, but without an enclosure. I am looking for your recommendations for HF driver / horn, XO and enclosure.

The 515 speaker was apparently mounted in the wall beside the stage of a a small community theatre in Ottawa, Canada, and was removed sometime in the 1970's. From what I can determine, the speaker is a Canadian version of the 515 and was manufactured under licence to Northern Electric (a Canadian affiliate of Western Electric). The model number is stamped as 515 and, oddly, so is the serial number. The speaker bell label also indicates 20 ohms. The speaker had been stored for many years, so I was cautious to break it in very carefully using my Eico Model 377 Audio Generator. Given that this is supposed to be a LF driver, I was surprised at the amount of HF info generated during test.

I then tested the speaker for several hours operating as though full range, and then using a Goodmans XO.950 15 ohm crossover and TreBax 15ohm HF driver / metal horn, playing a variety of FM radio broadcasts. I propped up the open baffle / original fascia configuration, Blue-Tak'd the TreBax to the top edge, and drove it with my Quad II mono set-up. This tuner, pre, amp combo usually drives my ESL57 tweaked mono speaker, so was my first benchmark. The sound room is 14 wide, 24 long, and 8 high, and heavily damped so reveals no significant colouration. Room is agreed by all to be a very good test bed as now houses 3 Tannoy Monitor Golds and 2 Rogers BBC Monitors for the 3-channel and stereo systems, as well as a single Tannoy Red and Quad ESL57.

I then drove the combo with two other reference systems. The second benchmark was the McIntosh MR55 mono tuner to the SoundMaster Imperial Ultra-Linear (Ottawa) integrated 6V6 amp and Tannoy Monitor Red 12" in Lancaster replica cabinet. The third was the mono Leak Troughline tuner, VariSlope III pre, and TL12.1 amp to a Tannoy Monitor Silver 12" in an original Lansdowne cabinet. I am very familiar with all these systems, so just swapped out the speakers for this test. Placement of the 515 was immediately between the ESL57 and the Tannoy Red, so there was as little variation as possible caused by room acoustics.

Testing of the Altec 515, even as seriously compromised by lack of enclosure, mismatched XO and HF driver, produced nothing but the most astounding results. I was amazed at the sensitivity that, in fact, seemed to improve as the hours passed. I have been a vintage Tannoy and ESL full-range fan for many years, and would not have ventured into Altec and VOTT territory, except the Altec came to me quite by chance.

Given my test results, I would like to explore this further and solicit your recommendations for HF driver, XO and enclosure in a mono configuration. I will likely drive this with another Quad II (12 w) or Leak mono (10 - 50 w) set-up. What are you recommendations?

[LICORNE]

One of the last horn cabinet produced by Altec Lansing in the mid 90's was the 816VIX.

Unfortunately the plans are not available on the web.

Here is the site for the cabinet as advertised by Altec.


http://www.altecpro.com/pdfs/vintage...%20Cabinet.pdf

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[LICORNE]

For the HF horn the MR994A 1" throat .Driver either GPA Altec 902,909.

http://www.greatplainsaudio.com/downloads.html

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