Hidizs MP145 Different Batches

Some time after the launch of the Hidizs MP145, one of the brand’s most successful IEMS, a controversy arose about their sound: according to individual comments, the first batches did not sound the same as the later ones.
To put an end to this kind of suspicion Hidizs sent me some new MP145s from the latest batch, with the intention of measuring and comparing them with the first one I own.

These are my measurements:

• The blue curve is the initial model.
• The green curve is the model of the last batch right out of the box.
• The green curve is the model from the last batch after 200 hours of use.

You can see that there is a visible difference in the first treble, from 4kHz and 10kHz.

But in the second comparison of the MP145 from the last batch with the Golden Titanium version, you can see that the differences are much smaller. Even so, the new batch of MP145s is still softer in the treble.

Hidizs told me the following:

«Regardless of the batch—whether first, second, or any other—the minor deviations within a reasonable range of ±2dB to ±4dB align completely with engineering specifications and production standards. This applies to HIDIZS MP145 and other HIDIZS IEMs.»

It can be seen that the differences between the MP145 from the first batch and the second batch are concentrated in that high end and can reach 4dB at some point. This difference can be audible and makes the MP145 from the last batch a softer IEMS in the high end. I’m not going to go into a deep comparison between the two models, I’m just publishing the graphs.