January 20, 2013

S3 prototype dispersion measurements

S3 measurements confirm very good dispersion control. Constant directivity has been achieved and pattern control has been maintained down to the Shroeder frequency of typical listening rooms. The - 6 dB line shows the nominal coverage angle - in this case 80 degrees nominal (or 40 degrees from the central axis as shown on the sonogram). The results have been gated and normalised. The floor reflection has been gated out and normalisation adjusts the axial measurement to a flat response. As a result, the sonogram shows dispersion rather than frequency response. One could achieve a similar result by using EQ to get the axial response flat, but this method is much quicker.



The vertical coverage is a little narrower than anticipated and this is a matter for further investigation. My initial supicion is that the dip around 5.5k may skew the result.

What is particularly pleasing with this result is that the beaming often seen before pattern control is lost on the bottom end, has been eliminated.


  1. Looks pretty darn nice, though a bit wider dispersion than I thought you were targeting? Perhaps I'm reading the maps incorrectly -- going by the -6db point, it looks like (from 1k to 6k) S3 was shooting for 80 deg and got 100. Granted, over a similar range, it looked like the old S2 was shooting for 90 and got 120.

  2. Hi Miguel,

    I'm very happy with the result, especially that the beaming before pattern loss was seen in the other versions, and the Yorkville particularly. The mouth termination was designed for this.

    Yes - you are reading them correctly, but I'll caution that in these measurements, the angles may not be entirely correct. It's a matter for further investigation and a new improved version of my rig.

    I've updated the sonograms with gated measurements.

    Initial listening impressions have been very good. Even with a quick 'n dirty crossover it's a very natural and balanced speaker. It only gets better from here.

  3. Hi Paul,

    Are measurements for the 4-mids or 6-mids version? Have you decided which one to go for yet and if so why?

  4. A normalised sonogram should show no significant difference, so just one of them was measured. The decision is not yet made, but I am leaning one particular way at the moment - not telling just yet. I will explain the reasons when the decision is made.

  5. Will you be providing distortion measurements e.g. comparable to Zaph?


  6. No - not at this time. I have my hands full at the moment.

    Perhaps down the track. What I can tell you right now is that The midrange distortion products are reduced by around 30 dB. That is a very large amount, greater than what is seen when comparing cheapo and high end drivers.


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