Well sorry for reviving this old thread, but I just tried this mod out of unquenchable curiosity.
The result are more interesting. I kept my SRH440 to listen to hard rock and metal, since I find they just sound more engaging than the treble-oriented Q701 for those genres. The drum has better crunch and low guitar notes more rumble than on the Q701.
I like to describe sound using the position of the listener relative to the band, and the difference in sound this modification brings can't be explained more accurately. The stock SRH440 always make me feel like I'm sitting on the middle of the stage with the mic stand of the singer right between my legs. Removing the plugs in the middle of the drivers is like moving behind the singer and sitting right in front of the kick drum. The drum steal the show. Everything else gets... second thoughts. Except maybe bass guitar, but that's to be expected in metal and rock.
When there's no kick drum or heavy bass guitar, you probably won't hear the difference. But when kick drum hits the first few times, followed by low bass guitars notes, you'll raise an eyebrow, I'm sure. The low frequencies are a lot more present without the plugs. I'm talking between 40 and 100 Hz. I am rediscovering my metal and rock albums and hearing new stuff that wasn't there before. At first it's weird, I can see how some people would turn away from the new sound. It can sound boomy and overwhelming on some tracks. I love the SRH440 for their balanced sound, but I feel like removing the plugs ruins that balance. I'll keep the plugs out for a few weeks until I get used to the bass. I'll then place them back in and see what I prefer. I might try to cut the plugs in half and see if I get a sound somewhere in between.
I did find something I thought some of you might find interesting. I never understood how the FR charts of Headroom and Golden Ears could be so much different, especially bellow 150Hz.
Well I think I now know how... From Golden Ears's page :
Note.
Please keep in mind that the following data are from a test unit reviewed by Golden Ears - the test unit is not necessarily a representative sample of the model being reviewed.
Here's my theory : Golden Ears reviewed a unit that didn't have the plugs inside the drivers.