{"id":2075,"date":"2012-05-20T17:23:53","date_gmt":"2012-05-20T17:23:53","guid":{"rendered":"http:\/\/www.audioexcite.com\/?page_id=2075"},"modified":"2012-05-20T18:06:03","modified_gmt":"2012-05-20T18:06:03","slug":"seas-h1189-27tdfc","status":"publish","type":"page","link":"https:\/\/www.audioexcite.com\/?page_id=2075","title":{"rendered":"SEAS H1189 27TDFC"},"content":{"rendered":"

Overview:<\/span><\/h3>\n

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\"\"<\/a>The 27TDFC (H1189) is a tweeter from the Seas Prestige series. It offers a sturdy build quality with a glass-fibre reinforced plastic faceplate. It has a wide, soft polymer surround and the coated fabric dome diaphragm provides a frequency response to 35kHz (on-axis), with a nice off-axis dispersion and low distortion.<\/p>\n

The Sonotex precoated fabric diaphragm has high consistency and excellent stability against variations in air humidity.<\/p>\n

Voice coil windings immersed in magnetic fluid increase short term power handling capacity and reduce the compression at high power levels.<\/p>\n

Stiff and stable rear chamber with optimal acoustic damping allows the tweeter to be used with moderately low crossover frequencies.<\/p>\n

This is a very affordable tweeter that measures very well and is capable of\u00a0 a 2kHz cross-over point or even lower if a steep filter is used.<\/p>\n

Seas Spec sheet: 27TDFC (H1189)<\/a><\/p>\n

T\/S Parameters<\/span>:<\/span><\/h3>\n

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Good consistency between the samples and they have slightly lower resonance frequency than the manufacturers specification.<\/p>\n

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Impedance:<\/span><\/h3>\n

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Free air impedance measurement:
\nSample 1 = Green
\nSample 2 = Blue<\/p>\n

A close match between the two tested samples. The use of ferro-fluid in the magnetic gap gives a well damped impedance peak at the resonance frequency, but at the same time gives the characteristic dual bump in the impedance commonly seen in some Seas tweeters.<\/p>\n

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\u00a0Frequency:<\/span><\/h3>\n

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Frequency measurement conditions:<\/strong><\/p>\n

The tweeter is measured flush-mounted on a baffle with the following conditions:<\/p>\n

Baffle size:<\/strong> (WxH): 24,8\u00d735,8cm <\/strong><\/p>\n

Driver position:<\/strong> Mounted on center-line with driver unit center 8,7cm from the top of the baffle.<\/p>\n

Mic position:<\/strong> 1m distance, on tweeter-axis.<\/p>\n

Smoothing:<\/strong> No smoothing applied.<\/p>\n

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0deg tweeter-axis:
\nSample 1 = Blue
\nSample 2 = Red<\/p>\n

Virtually the same frequency response between the two samples. Between 1.5-4kHz the baffle diffraction is noticed as dips and peaks in the frequency response. This is reduced in the off-axis measurements. The tweeter has a rising top-end frequency response from 10kHz. Very extended frequency response in both ends.<\/p>\n

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0deg = Blue
\n15deg = Red
\n22.5deg = Green<\/p>\n

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30deg = Blue
\n45deg = Red
\n60deg = Green<\/p>\n

Distortion:<\/span><\/h3>\n

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\u00a0Measurement setup:<\/strong><\/p>\n