Hello.
I'm trying to measure a DIY headphone driver in a pair of headphones I made and I'm a total noob at this measurement stuff so I'm looking for guidance and outside interpretation.
Not sure if my settings are correct but here it is.
linear waterfall plot
For some reason the log waterfall plot didn't display under 200hz unless I expanded the window to 60ms
Do my settings look alright?
Also what's the deal with all the valleys in the waterfall response? Is that really the driver decay?
And is there a method for smoothing out all those wrinkles in the FR?
Are those wrinkles audible? Is there something in this mess of data that I should focus on improving?
I'm trying to measure a DIY headphone driver in a pair of headphones I made and I'm a total noob at this measurement stuff so I'm looking for guidance and outside interpretation.
Not sure if my settings are correct but here it is.
linear waterfall plot
For some reason the log waterfall plot didn't display under 200hz unless I expanded the window to 60ms
Do my settings look alright?
Also what's the deal with all the valleys in the waterfall response? Is that really the driver decay?
And is there a method for smoothing out all those wrinkles in the FR?
Are those wrinkles audible? Is there something in this mess of data that I should focus on improving?
Speakers are far from flat.
A look at the speaker datasheet will show that.
A look at the speaker datasheet will show that.
An externally hosted image should be here but it was not working when we last tested it.
You say you are measuring headphones. The plots look too good actually. What equipment and settings are you using? I have measured hundreds of headphones and can help you get meaningful measurements.
Sorry didn't know anyone responded to this.
I'm using the UMIK-1 mic that is stuffed inside the tube of a paper towel roll and made flush against the end by filling in the tube with more paper towel.
I just hold it where my ear is expected to be.
I've since changed my settings a couple times.
This is a more recent measurement.
Using these settings
What can I do to improve?
I'm using the UMIK-1 mic that is stuffed inside the tube of a paper towel roll and made flush against the end by filling in the tube with more paper towel.
I just hold it where my ear is expected to be.
I've since changed my settings a couple times.
This is a more recent measurement.
Using these settings
What can I do to improve?
Last edited:
I think the measurements are good. You would need a reality check with a conventional headphone to get a sense of how your setup is measuring. There are a ton of interactions that have major effects on the measurements. Everything from the enclosed volume of the cavity to damping to the quality of the acoustic seal between driver and mike.
It looks like you are measuring at around 100 dB SPL. Thats pretty loud and its helpful to make sweeps at multiple levels.
The real pain in headphome measurements is that a flat pressure response doesn't sound right. Also a free field microphone will have a rolloff in the high frequencies in this pressure mode. For a 1/2" mike it will be down around 12 dB at resonance of the diaphragm. That would suggest your HF may be boosted. however that may actually sound right. The LF is strong down to the bass but it will be perceived as a little bass shy. Most headphones have a 6 -10 dB boost from 200 Hz on down to improve the sense of bass.
Attached are two plots of a headphone showing what you might expect. Curiously the red plot sounds pretty balanced. However with a difference housing/enclosed volume it might sound thin. I would focus on the waterfall to find resonances which are never good and will change some but not go away in a different test setup or measurement. Otherwise you may as well tune by ear it seems.
It looks like you are measuring at around 100 dB SPL. Thats pretty loud and its helpful to make sweeps at multiple levels.
The real pain in headphome measurements is that a flat pressure response doesn't sound right. Also a free field microphone will have a rolloff in the high frequencies in this pressure mode. For a 1/2" mike it will be down around 12 dB at resonance of the diaphragm. That would suggest your HF may be boosted. however that may actually sound right. The LF is strong down to the bass but it will be perceived as a little bass shy. Most headphones have a 6 -10 dB boost from 200 Hz on down to improve the sense of bass.
Attached are two plots of a headphone showing what you might expect. Curiously the red plot sounds pretty balanced. However with a difference housing/enclosed volume it might sound thin. I would focus on the waterfall to find resonances which are never good and will change some but not go away in a different test setup or measurement. Otherwise you may as well tune by ear it seems.
Attachments
I know a guy in New York that has measurements of almost all the highest end options and he claims they are much worse. I don't have his measurements on hand to share and I don't recall what I saw.
The driver is completely open with no encasement. I couldn't find any backing that improved performance. Almost everything just made it sound and measure worse.
The sound quality and dbs don't drop perceptibly before about 6 inches or so away, even in the low bass. The directivity itself has a huge degree of forgiveness, as long as the driver is pointed in your general direction there is little if any difference in perceived sound quality.
I place the mic right where my ear is expected to be and the paper towel imitates my head mass and skin texture to a decent degree.
I figured that if it did well @ 100db it would do better at lower dbs. Am I wrong in this assumption?
Hmmm. I think these are an exception in that case because there are no existing high end headphones that have more powerful bass than these. I know because I've tried almost all of them thanks to my friends in new york.
The bass power is insane, like head shaking, but also the highest quality bass I've ever heard and extremely quick, it's like the power is there and then instantly gone.
Also it is loud down to 20hz and audible down to 5hz which is cool. Whoever said 20hz is the lower limit of human hearing was not correct. I even managed to get a quite audible 1hz out of it by overdriving it. 😀
The driver is based on a weird concept I had several years back and seems to have worked out well.
I think one of the unusual factors for this driver is that it couples to the air around it like nothing I've seen which may be why it doesn't need to be enclosed and why the bass is so strong.
Unfortunately I accidentally destroyed the device after taking the drivers out of the headband and both drivers clashed into my finger and the magnets almost completely crushed my finger. Took a team of people to get the magnets off. That was about a month ago and my finger is no longer hamburger meat but my nail won't grow back for a while.
Lesson learned about magnets and fingers.
It will be a couple months before I can afford to rebuild it so I'm toying with other, less expensive things for the moment.
Last edited: