After many, many delays and much procrastination on my end, I am finally ready to introduce details and preliminary measurements for my Randy headphone measurement system! I am still trying to decide if "Randy" is going to be just "Randy," the name of the rig, or if it should be an acronym for something. $5 Paypal gift to whoever comes up with the best acronym for Randy, and an acronym I actually want to use. Behold the splendor of Randy! Background on the hunt for the Randy Rig: First, some background. My current method of measuring headphones uses a small mic, glued into a tri-flange IEM tip, which I insert into my ear canal. I try to keep the mic as flush with the opening of my ear canal as possible. This plugs into a little battery box and then into the mic-in of my Creative SB1240. One big downside to this is that it isn't comfortable. In fact, it hurts pretty bad, especially since I made the mistake of re-gluing the mic and tri-flange tip with super glue. Super glue isn't nearly as pliable at hot glue! That, and the mic starts to slip out of place once the ear wax starts attacking it. Or something like that. It's annoying. Another big downside is I can't fit this mic in my right ear properly, so that's why you almost never see right channel results. If you do, it's because the headphone was designed in such a way that I could just wear the headphones backwards, or similar, and measure the right channel on my left ear. On the upside, this method used a real head and ear. Sure, my ears are my ears, not an average ear from the results of 300+ humans and certified by old wizards that sit on an audio council. And I actually quite like how the results look with the mic at my ear canal, especially when using measurements to help describe what I hear. I only ever compensated for some bass droop from the battery box. The MiniDSP EARs rig looked promising, and it still has a lot going for it in terms of price and physical consistency for each user (mic consistency TBD). But I found it just a hair too small for my taste, width and height, and the ears appear to be a simplified representation of human ears. I wanted something more true to a real human ear, and even the to the contours of a real head rather than a flat coupler if possible. Also, I didn't like the way they used an ear canal. The way I see it, if you aren't going to accurately simulate the ear canal on a measurement rig, don't bother. But I'm really just a monkey pushing buttons compared to the real experts, so take my opinion for what little it's worth. This led to the following requirements: 1. Measurement results in the same vein as my current rig, if nothing else for ease of transition. I'll never be able to get a perfect 1:1 match, but I wanted this to keep on a similar course. 2. Ears meant to more closely mimic real human ears, averaged or not. 3. A head more closely proportioned to that of my own. Preferably, something that actually resembles a head and not a flat coupler. 4. If ear canals are not accurate to real canals (basically impossible on a budget), the ability to use mics flush with entrance of ear canal. 5. Ability to measure both channels without sticking anything in my own ears ever again. Enter the Randy Rig After some searching, I came across the Binaural Enthusiast B1-E Dummy Head with mics and battery box. While meant to be used for binaural recordings, I figured it would suit my purposes. This seemed to tick most of what I wanted for a few hundred bucks, and with how the battery box works, it was almost a direct drop in replacement for how I hooked up the in-ear mic rig. The head has a width more similar to mine (still a hair less wide, it seems) but did require me to add some cushion at the top to add more height for appropriate fit. I'm also lazy and don't like to have to adjust the headband when I transfer headphones from my head to the dummy head. What I really like is that the ears on this are modeled after real ears and are somewhat similar to my own. Of course, this means I still won't have results for that of the average human ear, nor do these ears have the pliability of the latest, greatest ears that GRAS uses. This also didn't cost me thousands of dollars. I had to remove the mount attachments, which was no problem. I also had to move the mics so they sat flush at the entrance of the ear canals. Since I'm not a robot, they're only as closely matched to the ear canal entrance as I could humanly manage. But I imagine that will be a minor source of variability between the two ears. I believe this utilizes the Primo EM172 mics, also seen in at least some of the 3Dio binaural measurement rigs. Once I had everything stood up from a hardware perspective, I got to work on a compensation curve. Preliminary Measurement Results (Custom Compensation Curve, Left Channel Only) Since I was pretty happy with how my results were turning out with the in-ear mic as of late, I wanted to try to base it off that. I'll admit that I also applied some influence from the target curve @Serious made for Tyll's measurement results a while back. (Thanks, Serious!) The process behind this mostly involved me measuring a few headphones, a mix of open and closed back over-ears, and dumping the results with 1:1 and 1:3 smoothing using the current, in-ear method. I then gathered raw, uncompensated results of the same kind from the Randy rig. I took a difference of the two and made some custom tweaks of my own, to put it simply. The 1:1 results are used for everything below 1KHz, with the 1:3 results used above 1KHz and in tandem with said tweaks of my own. So far, I've only been able to work out the compensation curve for the left channel. The mics aren't perfectly matched, which isn't too surprising, so I still have yet to work that out. However, I wanted to get feedback on what I have so far with the left channel before moving on. Here are a few headphones with the applied custom compensation curve compared to the in-ear rig: I'm happy with how the HD6XX and HD58X results turned out. Those headphones are really easy to measure, in that they are very consistent and are less likely to show massive variations between measurement rigs. You can almost always identify similar traits for these headphones regardless of what they were measured on. Almost no need to worry about fit and seal, so long as you have adequate clamping pressure. I expected, and received, greater variation between the two rigs with the MA900 and E-MU Purpleheart in particular. The MA900 can sound noticeably different depending on how you fit it on your head. With the in-ear method, I have physical feedback ensuring I have it seated like I would normally. I can't do that on a dummy head. In fact, I did get at least one measurement of the MA900 with less of a treble spike using the Randy rig. But I thought it might be more accurate to get an average of a few varying positions. I didn't do that so much on my own head, because I know how I like it to sit. (Should I go back to including a graph of all the measurements takes I averaged together in this case?) The E-MU Purpleheart is barely over-ear, but I tried to fit them similarly. Nonetheless, because of it's on-ear/over-ear in-between nature, I expected some variability. This one is a bit tough to get just right, but it's a good use case. I know the Mobius is somewhat of an unknown right now, but I wanted another sample to use for getting some average deltas between the two measurement rigs. It works well as a closed, over-ear headphone with minimal fit and seal fuss. So, while not well known, you can see the results nonetheless (with ballistics EQ setting). Besides, with a different head and different ears/pinna, you're never going to get the exact same results. I personally think these are perfectly serviceable results, given unknowns and variability will always play a role in headphone measurements. But what do you think? Steps Moving Forward 1. Based on feedback about left channel results, will finalize that compensation curve. 2. Move onto right channel results from there. Target being that the left channel should measure the same on both ears. 3. Distortion results still TBD. This mic does some things better than the in-ear mics (D3, D4 mostly) and some things worse (can't handle as much SPL, slightly higher D2 "floor" overall). I may need to incorporate the MiniDSP EARs for distortion results to get an accurate picture. 4. Still reviewing CSD results for Randy rig. So far, so good, though. Will share later. 5. Hoping to have moved on to using Randy rig exclusively by 2019 and giving my poor ears a rest.