As an owner of several IEMs with great sound quality but weak isolation I've been pondering this question for quite some time: would it be possible to use something like the Final Audio 1601 on the move with active noise cancelling headphones on top? Needless to say my inquiring mind wouldn't give me any peace, so I finally decided to grab some ANC headphones and do a field test to find an answer to that question...
From left to right: JVC FX700, Final Audio Design 1601SB, Radius DDM. Audio Technica QuietPoint ANC25 in the background.
Disclaimer: please excuse the lint in some pictures, those silicon rubber tips are like magnets in this regard. I'm not an untidy person, but neither an obsessively tidy one. :P
I did a bit of research to find a suitable ANC headphone and settled on the ANC25. I wanted them as small and light as possible, but with thick pads to accomodate my IEMs. The ANC25 are pretty small on-ears and weighing barely more than 100g they seemed to fit the bill. Moreover they're pretty cheap in the US, about $40 from amazon.com and a pricier but still tolerable £60 from iheadphones.uk for Europeans like me. The Amazon reviews weren't bad either, so I gave it a go.
First impressions, I really liked the design and looks of these! They're a bit delicate, but don't feel overly flimsy. And wow, they're light and pretty comfy, easy to fit with just the right clamping force! Keep in mind that I was not interested in how they sound (not that bad btw, but nothing to write home about), but only in their size, comfort and noise cancelling abilities.
So, after these positive first impression I proceeded with a small mod of their foam pads to make room for my IEMs:
Out of the box the phones have a thick padding made of foam that fills the entire ear pad (left pic - right earpiece). I removed the foam pads and cut out a hole in the center. Then I put the pads back on and inserted the cut out piece of cloth back into the hole to protect the driver from lint. The whole process was pretty easy and using a small pair of scissors took about 10 minutes.
I tried the result with my IEMs underneath and concluded there was enough space to make for a comfortable fit. The ANC25's foam is heat sensitive, so after putting them on you have to wait a few minutes for the foam to soften. Thereby it compresses by about 50% which still leaves enough room for each of the three IEMs I've tested.
Ok, I was ready to go now! I spent the whole last week switching between the JVC FX700, Final Audio Design 1601SB, Radius DDM while commuting on bus and subway and walking around in traffic and noisy surroundings.
So here are my impressions after a week of field testing:
Pretty easy. The FADs were worn downwards because they stay more securely in my ears that way, the others over-ear. After a bit of practice I had no problems putting the ANC25 over my IEMs and get a comfortable fit at first try. One leg of my commuting takes about 45 minutes during which all phones would stay reasonably comfy, except for the FAD's long metal stem getting pressed against my earlobes and calling for a slight repositioning every now and then.
One could rightly say that wearing headphones over IEMs defeats the purpose of having IEMs in the first place. This is certainly true, but keep in mind that these are very small and light and easy to stow away in your jacket pocket. Plus, they don't need cables. I usually wear a beanie or headband in winter to protect my ears from the cold, and these served pretty much the same purpose while being only mildly less convenient. The same wouldn't be true for hot weather, of course.
At first I was absolutely disappointed. This was the main reason for undertaking my quest and the ANC25 turned out to achieve only about 5db of passive noise cancellation. Switch on ANC and you may only add another 5db at best for constant noise like engine hum. ANC on these phones doesn't work for high pitched noise like screeching or very low rumbling, nor does it work overly good for fluctuating noise like a train pulling in/out of a station.
I was about to abandon the trial and call it a day, but then decided to follow through anyway. And sure enough, while actually listening to my IEM/ANC combo I learned that those meager 10db of additional noise cancelling can make a noticable difference in practice. Subway noise wasn't all absent, but suppressed to a level where I could concentrate on my music, neighboring chatter was pretty subdued and I had to strain my ears to catch announcements.
Overall I'd say that what small difference in noise levels the ANC25 were able to achieve made for a significant difference in listening pleasure, at least with the FX700 and DDMs, both of which have at least some weak isolation by themselves. Having zero isolation with their metal tips, the FADs did benefit the least because 10db noise reduction overall isn't that much in a subway. But at least they stayed securely in my ears, if not necessarily all too comfy so.
Wearing active noise cancelling headphones over open/vented IEMs has a certain impact on sound quality, because they allow for less air flow and create an outer acoustic chamber around your IEMs. I immediately noticed this resulting in more bass and less airiness and knew I had to try different tips to make up for these changed acoustic parameters. Here's a picture of my normal tip size (left) and the tips I ended up with for the DDMs:
Basically I settled on a very loose seal that would normally kill most of the bass, yet still got enough bass and a pretty balanced sound underneath the ANC headphones. Regrettably I wasn't able to fully compensate for the loss of airiness and maybe also lost a bit of soundstage, but overall the IEM/ANC combo's sound quality was almost like wearing the same IEMs without headphones and certainly better than any similar sized on-ear headphone I've heard.
Btw, obviously you can't change anything about the FAD's metal tips, but these were least affected by the headphones in the first place.
Wind noise. The ANC25 are pretty susceptible to it, so forget about wearing them out in the open. No problem on planes, trains or subways of course.
I have mixed feelings about wearing active noise cancelling headphones over IEMs to improve isolation. On the one hand this can do the trick if their own isolation is just slightly insufficient. But it won't work miracles for extremely bad isolating IEMs like e.g. the Final Audio 1601s and it opens another box of worms regarding sound balance and things like wind noise.
Here's a short summary of my field test:
+ Pretty cheap solution
+ Easy mod to make room for IEMs
+ Easy and mostly comfortable fit
+ Convenient handling (at least with small and light headphones like the ANC25)
+ Noise cancelling won't work miracles, but may still result in significant more listening pleasure
- ANC doesn't work for fluctuating noise
- Some impact on sound quality, tips need to be re-evaluated
- Wind noise
Thanks for reading!