- Written by Jim Clements
- Published on 02 July 2014
The Induction Dynamics ID1 Floor Standing Speakers On The Bench
All below measurements are in-room response. The frequency response tests were performed at 1-meter, the distortion measurements were on-axis near field measurements with the mic tip precisely 1’ from the driver under test.
The first test I ran was a 1 kHz sine wave at 90 dB SPL. THD measured just 0.17% with the first harmonic being 76 dB below the test tone.
Still tested at 1 kHz, but bumping up the SPL to 100 dB, the ID1’s THD rose to 0.54% and the first harmonic in this case was 59 dB below the fundamental.
The next test was 5 kHz and 90 dB. The THD was very low again at just 0.11%.
Then at 5 kHz and 100 dB, the distortion remained below the threshold of audibility and measured only 0.28% despite that there are signs of cone breakup in the test plot.
This plot shows the response of a 10 kHz sine wave at 100 dB. The titanium tweeter achieved this level of output at just 0.40% THD.
The Kevlar driver produced this 100 dB signal at 500 Hz with a very low percent THD, just 0.14%.
This plot is the output from one of the two subwoofers within the left channel speaker cabinet. 100 dB at 60 Hz with an incredibly low 1.08% THD.
The distortion rises to 4.87% when the frequency is lowered to 40 Hz. This is generally considered to be inaudible at this frequency.
I can hardly believe this test plot, but even at an ass-shaking 20 Hz and 100 dB, the THD is just 2.22%! Look how the first harmonic (40Hz) is 44 dB below the test signal. This low distortion and serious bass extension are among the many reasons these speakers could play back rock music at levels that mimic a live concert and do it cleanly.
Despite the floor bounce issues below 200 Hz; this is essentially +/- 5 dB out to 25 kHz. Many manufacturers claim this kind of treble extension but then fall short under actual test conditions, but not the ID1’s.
The off-axis plot is a little choppier than the on-axis, but the bass extension to 20 Hz is equaled by the treble extension that still approaches 25 kHz. That is why I liked these speakers with little toe-in.