FabFilter User Forum
How to adjust EQ to create a flat response for headphones
I found this graph in this page (reference-audio-analyzer.pro/en/report/hp/philips-shb-9100.php) that demonstrates the frequency response of a headphone of mine.
Now that I know the distortions of this headphone, could someone tell me how I can adjust the EQ accurately to compensate for these differences and create a completely flat response?
Rogério — Nov 18, 2017
You could do this by tediously moving adding bands till you visually matched it up. It would be amazing if someone developed software to convert frequency graphs from Headphone and Microphone spec sheets to a Pro Q2 frequency curve.
Well the EQ Match feature can already do that. Is there a standard file format for frequency spectrum curves? We could look into importing such a format in the EQ Match feature.
Cheers,
Wow that would be incredible!
The only kind of de-facto "standard" (scare quotes explained below) I know of for frequency response is the good old .FRD, still used a lot in loudspeaker design. It's actually a text file that you can open in Notepad and generally (again, see below) it looks like this:
* Manufacturer: Seas - Model: ER18RNX
*
* Freq dB Phase
225.1 83.6 76.6
237.6 83.9 75.4
262.6 84.4 73.4
275.1 84.7 72
...
It was defined by the long defunct FRD Consortium, a bunch of very generous and knowledgeable people who created a number of free, mostly Excel tools for loudspeaker design, such as simulation of crossovers, box diffraction, room response, etc. If I remember correctly:
- There could be some comment lines at the top preceded by asterisks
- Then you had lines with three numbers: frequency, level (in dBs) and phase (in degrees)
- The frequencies had to be in ascending order
- Some tools that didn't use phase information still had it there as 0 in all lines, so it was always three numbers per line
And that was pretty much it: I've seen them with / without comment lines, with varying numbers of decimals, with either tabs or spaces as separators, with extra spaces at the beginning of the lines, with scientific notation in some / all of the numbers... So as far as standards go it wasn't exactly strict, but nothing too difficult to handle from a programming point of view.
Interestingly, one of those tools was something called SPLTrace (iirc) where you could load an image file of a frequency response and generate by hand the corresponding FRD file, so if Pro-Q2 could import these, basically what Rogério wants would be perfectly doable.
And more, come to think of it: for example, I have Sonarworks and calibrated headphones and I can easily generate FRD files of my crossover designs, so I could listen to the speakers' "signature" and compare different versions before actually building them... This would be so cool!
The FRD website is long gone but I know where to do some digging, watch this space...
Cheers,
Although you can still get the FRD tools in places, here's an automatic tracer program that I just tried, it generates FRD files and works like a charm, just follow the instructions:
labs.fprawn.com/index.php/FPGraphTracer
Some discussion about it:
techtalk.parts-express.com/forum/tech-talk-forum/64837-new-automatic-graph-tracing-program
Cheers,
Cool, thanks for the info!
Cheers,
Hi...as per my knowledge this is a program that does exactly what you are asking for.The problem is that it does not support your particular headphone model: Philips SHB9100.It does support the SHB9500.
You would have to purchase another headphone that is supported by the program.