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Tweeters

SEAS#	Type	PDF	Size	Tweeter Description	Ω	Fs Hz	Buy VC	VC Ø mm	Power Watts	Sens. 1W/ 1Mdb
E0011	T25CF-002		25mm	"Millennium," Sonotex fabric dome, Hexadym magnet	6	500	H9929	26	90	88.0
E0036	T25C-003		25mm	Sonotex fabric dome, chamber, no FF	6	750	-	26	90	92.0
E0039	T29AF-001		29mm	Aluminum & Magnesium alloy dome, chambered	6	500	H9938	26	100	92.0
E0038	T29CF-001		29mm	Sonotex fabric dome, chamber	6	550	H9939	26	90	93.0
E0040	T29CF-002		29mm	"Crescendo," Hexadym magnet	6	500	H9939	26	90	92.5
E0047	T29MF-001		29mm	"Magnum," Magnesium Dome, NIB magnet 1	4	500	-	26	90	92.0

1. A neodymium magnet or NIB magnet is a powerful magnet made of a combination of neodymium, iron, and boron (Nd₂Fe1₄B).

Interpretting the PDF Data Sheets

Below, you will find some additional technical information that explains how SEAS performs their loudspeaker measurements. Power data specifications conform to IEC rule 168-5. The signal is white noise, shaped to a defined spectrum, and amplitude limited so that the peak voltage is two times the RMS voltage.

The short term maximum power is specified as the maximum noise power which the drive units can take without permanent damage for sixty cycles consisting of one second ON and one minute OFF.

The long term maximum power is defined as above but with ten cycles consisting of one minute ON and two minutes OFF. The mounting conditions in the above tests and during the sound pressure frequency response measurement are identical. Voice coil inductance is a controversial topic with no set standard for measurement. Loudspeaker impedance cannot be represented by a simple inductor at higher frequencies. We calculate the inductance value at the frequency where the impedance has risen 3 dB from its minimum above the resonance frequency.

Resonance frequency( fs ) is measured in the SEAS lab with a sine wave signal at 2Vrms across the driver terminals. There is no established industry standard signal level for measuring fs. For this reason, differing power levels and measurement methods may give significantly different fs, and consequently different values for all other parameters dependent upon fs. Suspension compliance (Cms) (the inverse of the suspension stiffness or spring constant) is related to the moving mass Mms and the resonance frequency fs by the equation: ( 2 π fs) ² . Mms . Cms = 1

Linear coil travel is specified as the total peak-to-peak distance the coil/cone can move with no significant change in the force factor.

Maximum coil travel is specified as the total peak-to-peak distance the coil/cone can move without experiencing gross mechanical non-linearities and limitations

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