Infinity S-EMIT (early 1980s)

The S-EMIT stands for Semiconductor-Electromagnetic Induction Tweeter. It was the semiconductor-driven version of Infinity's famous EMIT ribbon tweeter, introduced in the early 1980s. The original EMIT used a ribbon. The S-EMIT swapped in a soft dome driven by a large electromagnet instead of a conventional permanent magnet. Sources disagree on whether the dome was 1" or 2", so treat that spec as unconfirmed. A transistor in the signal path drove the electromagnet, which is where the "semiconductor" in the name comes from.

Documentation on the S-EMIT is thin, but the essentials are these. It was rated at 50W capacity, with a frequency range of 2kHz to 35kHz and a sensitivity of 104 dB. It was not a Ferrofluid-cooled design. It came with its own crossover, and it was used in at least one Infinity model, the Qa, where it was included in the stock crossover. It works at higher frequencies, so it doesn't see as much cone excursion as lower-frequency drivers. Owners report that this makes it more reliable than the original ribbon EMIT, which was prone to failure.

Replacement diaphragms are 8 Ohm. Original S-EMIT diaphragms are rare and expensive, and the driver is no longer manufactured. Aftermarket replacements exist but aren't identical to the originals. Owners note that the S-EMIT can sound bright if the crossover isn't properly matched. Audio (January 1988, p.128) praised the speed and detail of the related Kappa series' upper midrange and treble, and noted that Infinity's planar designs approached the openness of ribbon designs.

Known Specs

• Type: Super tweeter / high-frequency driver (electromagnet type)
• Capacity: 50W
• Sensitivity: 104 dB
• Frequency range: 2kHz – 35kHz
• Replacement diaphragm: 8 Ohm
• Includes its own crossover

eBay Listings

PAIR (2) Infinity S-EMIT Super Tweeter Repair Parts • TWO Pi

$48.00

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