This is a review and detailed measurements of a custom Grado headphone with Elleven Acoustica R1 driver. It was kindly sent to me by a member. I don't know how much it costs. The R1 driver is 119 GBP/pair (about US $164). The gorgeous cups were made by Bruce at Wabi Sabi headphones out of cherry and mahogany.
As a woodworker, I find the overall execution simply gorgeous:
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I am not going to give you the usual physical stats because this is a custom product. Wearing it, my left hear was touching the driver and this became uncomfortable after about 15 minutes. Otherwise, they are quite light and easy to wear.
Note: The measurements you are about to see are made using a
standardized Gras 45C.
Headphone measurements by definition are approximate and variable so don't be surprised if other measurements even if performed with the same fixtures as mine, differ in end results. Protocols vary such as headband pressure and averaging (which I don't do). As you will see, I confirm the approximate accuracy of the measurements using Equalization and listening tests. Ultimately headphone measurements are less exact than speakers mostly in bass and above a few kilohertz so keep that in mind as you read these tests.
If you think you have an exact idea of a headphone performance, you are likely wrong!
Fitment on the fixture was a bit tricky given the on-ear configuration and lack of measurements elsewhere to confirm fit. But consistency between channels was surprisingly good so I ran with them.
Grado With Elleven Acoustica R1 Driver Measurements
As usual, let's start with headphone frequency response measurements:
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Can you spot the problem?
![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Sometimes it is this easy. We clearly have a massive peak around 2 kHz that doesn't belong there. That is followed by a dip. In addition, we have the bass droop which is common in many headphones. Here is the relative response for equalization purposes:
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Distortion is focused in bass as it usually is but also an unfortunately one around 4 kHz:
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Sadly we need to boost both of those areas so you are dealing with distortion graphs in red or possibly in green depending on how loud you listen. If you don't EQ and play at low levels, then response is in blue and good.
Group delay shows the common messiness which is likely due to reflections back and forth between the driver and the artificial ear in my measurement fixture:
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Impedance is low and variable:
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I was surprised how good the efficiency was:
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It is in IEM class! Large driver at very close distance to the ear is responsible for that. Indeed I was able to drive these to reasonable level using the IEM output of my RME ADI-2 Pro DAC and headphone amplifier.
Headphone Listening Tests and Equalization
Instant reaction to the sound was that it was all wrong. So I brought out the EQ tool almost immediately:
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The first three filters had a dramatic effect, completely transforming the sound of this headphone. Now we had balanced bass, decent spatial qualities and none of that overboosted mid-range. The highs were a bit distorted -- the same way I have found with other headphones with the same distortion profile in lower treble. So I added the last filter there in yellow but it didn't seem to make a lot of improvements.
Conclusions
Not sure who all has use for all of this data. I guess you have a sample data point for Eleven Acoustica's R1 driver. I guess the lesson is that if you are going to build a custom headphone, measurements are essential. Trying to guess that peak around 2 kHz by ear is darn near impossible. With measurements and equalization however, you can build a performant headphone and have pride of ownership knowing you built it.
P.S. Sorry about misspelling of "Acoustica." I cut and paste the string as the owner had written and didn't catch it until now.
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