Specifications
Weight: 408gr
Nominal Impedance: 13ohms
Distortion: <0.3% ref 94dB at 1KHz
Frequency Response: We do not publish this because no standard exists for what this actually means and far too many vendors simply publish absurd numbers in a spec game. We don't.
For the community, I have been working on a port of the Harman 2018 curve from the reference GRAS 45CA to the B&K 5128. The curve shown as the target was derived and verified using two independent processes, and with input from Sean Olive. This curve should be considered an Alpha target and not definitive but it is interesting for several reasons.
View attachment 450202
First, the areas that fall above or under target are extremely close to those measured on the 45CA, in other words where you see a bump above or below curve on the 45CA you will see a similar feature on the 5128 relative to the reference curve. This gives a degree of confidence in the results.
Second, it is worth noting that the Harman 2018 curve is almost universally used with KB5000 ears, but when it was developed Sean used a modified version of the original KB0065 ear. The two ears do not have the same response, which creates a built-in error above 9KHz on any KB5000 equipped ears. This is something that has been known, I believe, but not thoroughly discussed, and will also get some attention in my write up.
More details on the development process for this curve will be shared with the community the week after I return from the Munich High-End show. It will be interesting to see assessment by others of the potential 5128 curve, especially if they have both the GRAS and B&K