Ti dome HF breakup notch filter sims

For those interested in removing the HF breakup peak on a 25 - 28mm Ti dome tweeter, here are a few calculations I've made to accomplish this. You can get very close to the actual shape of the peak with a very simple filter.

I've tried this notch filter with my Audax TW025A28 Ti domes and it works very well. Looking at the 16 dB+ peak at 25.5k, its not a bad idea to try taming this dog whistle of a peak. You can vary the peak amplitude by changing the parallel resistor. In my case, 33R is the value that worked best. I used my Earthworks measurement mic to verify this which is flat to 30k.

A trained ear can definitely hear a difference with recordings that have extension past 20k, mainly classical and acoustic music. It passes the "triangle test" and also playing cymbals.


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Yes, the true benefit of this is a reduction in down modulated HD components, which can wreak havoc on overall THD. Just like a really live sounding metal cone driver, it will cause side band components which are easily distinguished from standard in band breakup modes. A good example of this sort of driver is the Seas W15CY, as it has a similar single sharp breakup mode, which can be heard even with a crossover slope attenuating by 24 or more dB.
I made measurements which I couldn't capture due to the setup itself. I use a gated spectrum analyzer which doesn't have a means to export a graph or data. Pulling out the PC to do this is a massive hassle for me, mainly because the other setup is always ready to go and uses a compact display based on Android. Sorry