Love this stuff, Hans, keep up the good work.

It's exactly this kind of adept enthusiast market that will keep manufacturers on their toes.

Thanks, guys! I need to invest in a better SPL meter for calibration purposes. The one I got only worked for a few days (questionable quality, in the end), so while my results aren't too far off what I'd expect, that's something I'll want to double check. This doesn't change the frequency response so much, but for adjusting the level of the mic-in, it strongly affects distortion results. So, really, it's mostly down to better calibrating everything at this point.

I'm thinking about incorporating a few more tweaks and a couple other common tests with my measurements. I know HeadRoom provides harmonic distortion measurements showing the full spectrum given a single sine wave (500Hz). Those are really quick and easy to grab with ARTA, so why not throw that in with what I do? I use that for calibration purposes before I grab the swept sine FR/CSD anyway, so it wouldn't make sense to not grab it then! Some other type of measurements I'll have to figure out how to do properly, if I want to include them. I'm open to and considering anything that might provide more information about what we're hearing subjectively!

Really, though, it all came down to Keith/BMF over at Head-Fi offering a chance to test out a measurement kit (which I have since purchased at an extremely reasonable price). I was initially afraid his particular kit wouldn't offer accurate results, but I have to say I have been pleasantly surprised by how decently the results actually match what I hear with just a bit of tweaking. I was even more surprised by the relatively consistency the measurements offer, but perhaps this is because I get tactile feedback when placing the headphone on my head. That more likely ensures a good fit/seal and fairly consistent placement. All in all, where as I thought this sort of measurement setup might not be good enough compared to a "dedicated" measurement rig (i.e. for worthwhile public results), I believe it may actually have some inherent benefits/strengths and act more as a good complement to the many dedicated rigs...just as the different dedicated rigs also complement each other with their variances.

Though, I'd also like to rule out product variance and measure one or two of the exact same headphones Marv and UB have also measured, just to see how close my measurements are. Not that they have to match exactly by any means, but as a reference. Then again, some HPs I've measured show a good number of similarities on par, IMO, with variance across other measurement rigs.

OK, took the time to get some better measurements of the Alpha Dog. These do indeed seem to have a bit of a channel imbalance. It seems to primarily affect the position of male vocals.

Compare to what ultrabike posted, though I'm not sure which revision he measured: http://www.changstar.com/index.php/topic,1208.msg32468.html#msg32468

1. Alpha Dog, left channel, no felt discs
2. R, no felt discs
3. L, 1 felt disc
4. R, 1 felt disc

I have a new SPL meter on hand, and it doesn't seem to be quite as, well, broken as the other one. I'm hoping to really narrow down on my calibration settings with this. I haven't had a good opportunity to use it yet, though.

Haven't touched my compensation curve recently. I'm feeling pretty good about it for now.

One major revision is a change in the software I use to represent the FR/HD graphs. I am still measuring with ARTA, but I use Excel to generate graphs from the exported CSV data. This gives me a lot more flexibility, though getting the graph template the way I wanted took some time. As I said, overall system calibration isn't spot on yet, but my attached example demonstrates what I'm pushing for in the end (i.e. demonstrates 1KHz at 90dB, but I may include or switch to white noise if this SPL meter isn't a POS like the other and can read it properly). The graph is also larger and cleaner overall, so it should be easier to read. I'll eventually provide a graph that shows only the left and right channels as well.

But, perhaps the largest change is that I am now presenting my measurements as an average from several takes. This graphs is from 3 averaged measurements, though I hope to do 5 for each channel in the future. Each time, I remove the headphone, check the mic to make sure it is seated properly, and put the headphone back on before measuring again. I do try and let the headphones and pads warm up on my head for a few minutes first, but this particular graph was not done as such (fairly quick measurement). In the future, I'll try to include the raw measurements as well.

In general, I'll post more details about my methods once I have things more finalized.

For now, I've attached an example of the left channel on my now-modded MDR-1R. First, I wanted to note that in order for the minor gridlines to show where I wanted, I had to set the minimum on the X-axis to 10Hz instead of 20Hz. I wouldn't worry too much about measurements below 20Hz on my setup.

Though the compensation curves I used for this and my stock MDR-1R measurements aren't exactly the same, they are (quite) close enough that you can see this modded pair is improved in many ways. Some areas may not be as good as a tradeoff/for the greater good. My stock pair sounded pretty darn bad. These are actually fairly decent, though still only at low/medium volumes. (Internal damping mods, HM5 pads modded to mount with original pad ring and also taped to baffle, open tuning hole on top of cups closed by about 2/3. Yes, these did lose some sub-bass and even gained some lower distortion, but they sound much cleaner, less bloated, and less mid-bass heavy overall than they did stock from a subjective standpoint.)

Still using ARTA to generate CSDs. It does what I need with ease.

Let me know if you see anything you like, anything you think could be improved, or just have any thoughts in general!