Can there be some form of multitone test for headphones/IEM's?

[frgmnt]

I've been wondering if there was some way to measure the "intangible" attributes of headphones. I saw that there was a multitone test for DAC's. It is to my understanding that test is to measure how much distortion the DAC is outputting multiple tones played together. Is it possible to have a similar multitone test set up and measured for headphones? I'm nowhere near an expert when it comes to sound engineering, so I do not know if the DAC's own multitone testing, volume output of the headphones, or the headphone's frequency response need to be taken into account.

I know there is currently no way to measure these terms that audiophile reviewers love to throw out. There's definitely many people way smarter than me that have put some thought into this and it is why we only have the current measurements for headphones. This is just a question I tried to lightly research and I had no idea if some kind of multitone test with headphones could tell anything useful.

 

[SSS]

Interesting question. In genereral it should be possible to use multitone for evaluation. There is little data on measurement microphone distortion. So it is probably hard to distinguish between headphone and microphone distortion. Would be great if anybody here could contribute with experience on this topic.

 

[voodooless]

Is it possible to have a similar multitone test set up and measured for headphones?

Yes, it is possible to do this, and it's probably a useful metric. There are, however, a few caveats to consider, and this is also the primary reason that @amirm doesn't do this for speakers and headphones/IEMs. The main reason is that interpreting these graphs is not as simple as with DACs and amps because the frequency response isn't flat. That makes it a lot harder to compare one graph with another. I do, however, think that these types of graphs are quite interesting and useful to have, particularly to see the effects of intermodulation distortion, but also to see the influence of a high-pass on distortion and intermodulation for smaller 2-way speakers.

@Joseph Crowe regularly uses multitones to access the performance of drivers, for instance here:

Bliesma T34B-4 on Waveguide No.2439

Introduction In this blog post I test a new waveguide design that I came up with for the Bliesma T34B-4 Beryllium dome tweeter. The specification page for the T34B-4 can be found here. The tweeter retails for around $500 USD. I directly compare this new waveguide/tweeter combo against the RCF...

josephcrowe.com

 

[SSS]

Short search shows measurement of microphones here:

Microphone Distortion Comparison

In this blog post I compare distortion performance between four different microphones. From left to right I have the following microphones. Dayton UMM-6 I've used the UMM-6 for about a decade now and it has served me well. It is the only USB microphone in this test. The microphone retails for...

josephcrowe.com

 

[frgmnt]

Yes, it is possible to do this, and it's probably a useful metric. There are, however, a few caveats to consider, and this is also the primary reason that @amirm doesn't do this for speakers and headphones/IEMs. The main reason is that interpreting these graphs is not as simple as with DACs and amps because the frequency response isn't flat. That makes it a lot harder to compare one graph with another. I do, however, think that these types of graphs are quite interesting and useful to have, particularly to see the effects of intermodulation distortion, but also to see the influence of a high-pass on distortion and intermodulation for smaller 2-way speakers.

@Joseph Crowe regularly uses multitones to access the performance of drivers, for instance here:

Bliesma T34B-4 on Waveguide No.2439

Introduction In this blog post I test a new waveguide design that I came up with for the Bliesma T34B-4 Beryllium dome tweeter. The specification page for the T34B-4 can be found here. The tweeter retails for around $500 USD. I directly compare this new waveguide/tweeter combo against the RCF...

josephcrowe.com

I see. I figured the FR of the headphones would throw off the multitone test a bit, but looking at those tests by Crowe, it still seems to show a rough visualization of how the drivers perform playing multiple tones. The only way to really tell if these tests are informative or not would be if a range of different headphones and IEM's were tested with this kind of test and other similar extensive tests that @amirm performs.

I feel like there's room for a Youtube headphone/IEM reviewer that supplement their reviews with similar tests while explaining it clearly. Maybe that might be too much to ask for. I know I don't have the camera personality or funds to test out so many headphones/IEM's. I just find it so convoluted when reviewers talk about all these "intangible" qualities of headphones and all we get to see is a FR graph. I've definitely heard headphones/IEM's that have a FR that looks like it would be decent, but still sounds poor quality in terms of clarity/detail.

While I do realize a big part of the sound we perceive comes from the FR and how our mind processes the sound, I feel like how we measure or show the technicalities of headphones can be expanded to paint a better picture of them.

Sorry if all this seems like a long rant. I'm just hoping that by bringing this up, in the future we can get more than just impedance, sensitivity, and a FR graph when looking at headphones.

 

[amirm]

As noted, I don't find the graphs easy to use. I started running it back when. Here is an example:

As you see, it looks nothing like DAC tests. Ambient room noise is a problem in low frequencies and the rest is highly dependent on frequency response.

I also tried it with just two tones but didn't get anywhere conclusive with that either.

It is one of those things that if I can't make sense out of it, I can't include it in the reviews.

 

[frgmnt]

@amirm Thanks for the reply! Really appreciate all the work you've put in with measuring all sorts of devices. Just noticed your sig and saw that you have a YT channel. I feel like a fool for saying that there needs to be someone on YT doing these kinds of measurements in reviews lol. Might be because my YT searches for audio is usually for direct reviews of the products I am interested in at the time. Going to be going through your videos now to try to educate myself.