When we EQ, how do we know it even works as dialed in?

[Tks]

Like when we bump up 6db at 2kHz for example. How do we know every headphone we use is going to apply that much boost eventually if we measure the final signal with a mic for example?

I would imagine one headphone would do perhaps a 7db boost, and another 5db boost instead, seeing as how sensitivity ratings and impedance vary?

I get that it doesn't literally mean 6db will be pumping out of your headphones now at 2kHz, and it's simply a signaling of that much boost is being sent to the DAC and eventually the amp. But does this eventually occur if we have all sources at dbFS?

I feel like I'm intuitively thinking and missing something so obvious that it's silly.. yeah electronics isn't an industry I hail from :-\

 

[Blumlein 88]

I'm not sure I get the question. If you boost 6 db at 2khz, then the transducer will get that boost too unless you are boosting a cancellation null. The other case is when you have pushed the result past 0 dbFS in which case you'd get clipping of waveforms around 2 khz.

 

[RayDunzl]

I feel like I'm intuitively thinking and missing something so obvious that it's silly..

If the headphone doesn't respond predictably to EQ voltage changes, it wouldn't respond to musical voltage changes.

Changing the volume (voltage change) would change the frequency response.

I don't see that in speakers, within their operating limits, and wouldn't expect to see it in headphones (little tiny speakers).

So, I wouldn't worry along that path.

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Caveat: the headphone has reached the limit of SPL it can produce cleanly at some frequency at which you are applying boost.

 

[Tks]

Thanks guys. I wasn’t really worried, I was just wondering if particular frequency boosts or changes (under clipping levels) would effect eventual output of that boost amount depending on volume level.

But as Ray pointed out (duh) we’d be having FR shifts by changing volume (which we don’t). Well at least not in the area that matters (audibility).

The reason I asked, is because when I see TDH metrics change based on volume output to the listening device. I wondered if such increases or decreases in volume could have FR effects of an appreciable level (seeing as how THD changes). Seems like ‘not really’