The Luscious Denon AH-D2000, AH-D5000, and AH-D7000 Page 2
Making Good Better
This review took me far too long to write. I've had a personal pair of D5000s for years now, and am very familiar with all the cans in the line. When I decided to do this review, rather than bugging HeadRoom to borrow their sales demo units for an extended period of time, I called Denon to acquire some current samples. Boy, am I glad I did, but it was disorienting for a while.
First, I unboxed the three headphones and stuck them on my burn-in station for a week or so. Once I figured they'd cooked long enough, I sat down for a preliminary listen. They sounded pretty much as I expected, except they were a bit smoother and tighter than I remembered, and I had a fairly hard time telling the differences between them at first. I figured it it might just be an off day for my ears or something. Then I measured them.
The above data are plots of the compensated frequency response of the new Dx000 with the old headphones in the line-up. I was concerned that the old ear pads may have worn over time, so I put the new ear pads on the old cans prior to measurement to ensure an apples-to-apples comparison. What's obvious from the data above is the new series of headphones measure more closely to each other than the older headphones. I wouldn't characterize these differences as huge, and if you've read the recent article by Macedonian Hero on my measurement system's repeatability you'll know there's a good bit of room for error, but I feel the change is large enough to be real and moderately audible.
This really peaked my curiosity, so I decided to give Mark Lawton (of Lawton Audio) a call. He has many years of experience modifying these cans, I figured if anyone would know of these changes, he would. He was surprised to hear of my findings, and said the only change he was aware of was the he had started to see some stickers with numbers on them appearing on the rear of the magnesium frame starting about a year ago. I decided to do a little more digging, so I put the old and new D5000 on my bench to take them apart and really scrutinize the two for differences.
First, the internal foam of the new pads did seem to be a little more pliant than the old pads, and the synthetic leather material was slightly softer and more flexible. However, since I measured the differences with the new pads on all the cans, this change couldn't have been the source of the differences.
I got out my calipers and made a number of dimensional measurement of various parts and didn't find any changes. But as I did some really close visual examination I noticed a couple of things.
In the picture above, you can see the rear of the magnesium frame of the old (left) and new (right) D5000 headphone. The "L" shaped slots are used to attach the ear pads to the frame. On the new frame you can see a bump next to the "L," this is a detent to prevent the pad from easily rotating and becoming inadvertently unattached. On the old frame, there is a tiny bump inside the "L" that serves the same purpose. I suspect the designers got too many complaints about pads falling off and redesigned the part.
Interestingly, the new D2000 uses this old frame. This part is manufactured using magnesium injection molding. (Here's a short article.) The molds used in this process wear over time, and are very expensive to produce. My guess is that in an effort to cut costs, the old molds are being used for D2000 production to save wear and extend the life of the new molds used for the current D5000 and D7000. Unfortunately, I couldn't identify any differences to this part that might account for the sonic changes observed in the frequency response data.
The other change I noticed is that the foam damping part around the driver has a slightly more open-cell structure. This is not so clearly evident in the photo above, but was apparent to the naked eye. This change certainly could produce the modest tweak to the frequency response of the various headphones observed. However, I also noticed that the D2000 still has the old foam. Maybe they're using up the old parts on the D2000 until they run out.
Here's the bottom line: the headphones have changed. Not a lot, but enough that headphone enthusiasts probably need to be very careful about holding on to their well-formed but now somewhat obsolete opinions about the sonic differences between these headphones.
I'll talk next about how the 2012 Denon headphones sounded to me...