ScanSpeak Illuminator Tweeter Measurements!

December 13, 2012 Posted by gornir


On the test bench this time I’ve measured and compared two different compact sized tweeters from the ScanSpeak Illuminator series, the R3004/602010 and the D3004/602010.

For measurement details see:

ScanSpeak D3004/602010
ScanSpeak R3004/602010



These two tweeters are essentially the same tweeter. They share the same housing, face-plate and motor system. The “R” version is the ring dome version and the “D” version is the 1” textile dome version.


If we compare the two tweeter versions they differ as follows:


  • Ring dome diaphragm
  • Phase plug design
  • 5.6cm² effective piston area.
  • 2dB lower sensitivity than the “D” version.
  • More linear on-axis frequency response (<30deg off-axis).
  • Slightly higher distortion than the “D” version.
  • Costs about 35$ more than the “D” version.



  • 1” textile dome diaphragm
  • 7cm² effective piston area.
  • 2dB higher sensitivity than the “R” version.
  • Better off-axis frequency response (>30deg off-axis).
  • Slightly lower distortion than the “R” version.


(click on picture to zoom)

Blue = “R” version

Green= “D” version

If we look at and compare the tweeters impedance response, we see that they are almost identical. The “D” version has about 0.2 Ohm higher impedance than the “R” version.



(click on picture to zoom)

Blue = “R” version

Red = “D” version

Upper Left: On-axis @ 1m

Upper Right: 15deg off-axis @ 1m

Middle Left: 22.5deg off-axis @ 1m

Middle Right: 30deg off-axis @ 1m

Lower Left: 45deg off-axis @ 1m

Lower Right: 60deg off-axis @ 1m

If we look at the frequency response graphs, we can see that the “R” version has a very linear frequency response (+/- 1dB 2-20kHz) on-axis and up to 30deg off-axis. The “D” version has better off-axis dispersion above 30deg off-axis.


(click on picture to zoom)


Blue = With protective grill

Red = Without protective grill

For those who doesn’t like the look of the protective grill, it’s safe to remove it since it doesn’t affect the performance at all. It’s very easy to remove and re-attach the grill as needed without breaking it.


Which one to choose? That’s hard to say without subjectively listened to both of them in a loudspeaker design. Based purely on the measurements I would say that the “D” version has better price/performance ratio than the “R” version.

If you value pretty looking frequency response graphs or need extreme tweeter linearity on-axis, doesn’t need the extra sensitivity and isn’t price sensitive, go for the “R” version.

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