A guide to reading frequency response graphs of headphones and IEMs.
Frequency Response measurements and graphs for In-Ear Monitors (IEMs) and earphones
Setup: Laptop PC > Room EQ Wizard > Motu M2 audio interface > B&K 1704-C-102 CCP signal conditioner (USB bus power) > GRAS RA0402 pre-polarised “high resolution” IEC603318-4 coupler > GRAS KB5000/KB5001 artificial pinna (right and left respectively)
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*Note: All headphones are measured with stock pads unless otherwise stated.
1. A Frequency Response graph is not in any way an indication of good sound quality. Think of it as flavours, like in ice-cream. The FR is like the branding at the side of the tub telling you the flavour of the ice cream. It’s not going to tell you if it’s good ice cream, but at least you have a way of finding out if it’s the flavour you want.
2. Measurements in this database are raw and do not conform to any rigid industry standard. The measurements in this database are best used as internal comparisons rather than cross-referencing to other databases.
3. Flat on the graph DOES NOT MEAN flat in real life. The fact that headphones bypass the head necessitates higher SPL in the 2-5k regions as compensation (see: Diffuse Field, Head Related Transfer Function, Harman Target).
4. Measurements are meant to complement subjective impressions, not form the basis for them. I get that certain people like to paint me as some sort of objectivehead figure where all I do is look at graphs and determine quality sorely off of said metrics. 99% of the headphoness I’ve measured, I have listened to as well. If not for the graphs, one can also take this database as a list of headphones I’ve tried and auditioned, and the graphs simply being proof of it.
5. Unit variation is a thing. I do not control what demo units the companies provide to me or to their distributors (where I usually do measurements). If you find issues with my measurements, it can be any of the following:
a) Inconsistent manufacturing
b) Broken/malfunctioning units (in a way that is not immediately obvious)
c) Horrible channel matching
d) Measurement error (yes, I am human, I make mistakes sometimes)
6. The measurements are performed with the assumption of a “perfect seal”. Placements that results in abnormal rolloff are scrapped and re-done until a proper seal is achieved.
GRAS 43AG-7 partly funded by:
Special thanks to >$50 contributors:
Tareq Abou Samra
In-Ear Fidelity is supported by the following: