A Traveler's Sanctuary: The Bose Quiet Comfort 20 Noise Canceling Earphone Measurements

Measurements (noise canceling active)
Click on graphs image to download .pdf for closer inspection.

Compensated frequency response plot shows a headphone with a very linear response between 30Hz and 2kHz, with normal subsequent dip, and then a peak at 10kHz that does not exceed the line drawn from 30Hz to 2kHz. Other than maybe 5dB more response at 6kHz, response to 10kHz is near ideal. Response above 10kHz should be about 15dB higher; these cans do lack air and finesse above 10kHz.

You'll notice bass is nicely extended and flat to 30Hz, but the 30Hz square wave has a dramatic downward curvature. This indicates to me that while response is good to low frequencies, there is also significant phase shift in the bass. THD+noise plots in the bass show a gentle rise, but not so much that one would expect a thick, distorted bass. In listening I did find the bass well extended and strong, but lacked that last bit of punch realized with tight, in-phase bass response.

The leading edge of the 300Hz square wave is quick and has an appropriate overshoot, but the following 0.001 sec of the waveform is a bit grungy before setting down. This can also be seen in the impulse response with a clean initial pulse, but subsequent noise is somewhat excessive. In listening tests I heard this as a "papery" and somewhat grainy sound. It's important to note that I've regularly seen much worse noise in these plots, and feel that Bose has actually done a remarkable job controlling these cans in the time domain. Considering the amount of electronics and DSP going on here, I'd say these measurements are very good results.

While there is a mild distortion peak at 500Hz in the 100dBspl THD+noise plot, distortion levels in general are low and quite good. This plot might indicate some mid-range distortion at high listening levels, but I didn't observe this during listening tests—it's likely somewhat masked by the more obvious troubles with the treble grunge.

Electrical impedance and phase plot show the control module having about 3 kOhm input impedance when activated, and modest electrical phase shift.

The broadband isolation measured (100Hz - 10kHz) of the QC20 and QC15 are identical at -26dB—the best of all noise cancelers I've measured to date. The QC15 does better in the lowest and highest frequencies, but the QC20 provide a more even attenuation over all. I preferred the isolation of the QC20 over the QC15; it just seemed more natural and better.

With 93mVrms needed to reach 90dBspl I found myself running the volume controls up pretty high, but I think most folks will get plenty of volume from these in portable applications...especially since the background noise is so well attenuated.

The Bose QuietComfort 20 measures spectacularly well for a noise canceler!

Measurements of the QC20 in Other Modes

Aware Mode

Click on graphs image to download .pdf for closer inspection.

As you can see, all measured parameters remain unchanged in Aware Mode with the exception of the amount of isolation. The isolation plot shows virtually no attenuation of outside noise from 100Hz to 2kHz permitting the full range of the human voice including speech intelligibility cue to be audible. Some attenuation of the bass and mid-treble and up is also present. It seems to me this is a good formula for hearing others while reducing some rumble and hiss.

Passive Mode

Click on graphs image to download .pdf for closer inspection.

Passive mode performance of the QC20 shows a significant reduction in bass response below 100Hz; mid-range response becomes more uneven. Overall, a course pass on a moderately well balanced response, and heard that way.

30Hz square wave has poor shape, and little energy left by the end of the waveform, echoing the steep <100Hz roll-off of the bass frequency response.

300Hz square wave show lack of leading edge spike, and is heard as having a muffled treble relative to active mode. Confirmation to me yet again that some leading edge overshoot is desirable.

Impulse response shows a less responsive initial pulse, and more subsequent noise. THD+noise measurements also significantly increase. Comparing these measurements with the QC20 in active mode is convincing evidence that Bose did a good job with the headphone correction component of their DSP software.

Impedance and phase plots don't tell me much except that the signal is probably capacitively coupled, and that the primary driver resonance is likely just under 2kHz.

I find the isolation plot in passive mode quite interesting. Generally, the QC20 StayHear+ tip provides little isolation in the low and mid-frequencies, which doesn't surprise me in the least, but isolation above 2kHz seem to be reduced with the noise canceling active. I suspect high frequency isolation is actually remaining unchanged, but additional noise from the noise canceling circuits are appearing.

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COMMENTS
Jazz1's picture

I'm tempted by these. Most every coffee shop and sandwich shop I frequent for lunch has music blaring or the flat screen cranked. What good are high end headphones if outside noise overrides your own higher end headphones?  

Jazz Casual's picture

Nice to see a Bose phone receiving bouquets rather than brickbats for a change.

Jazz1's picture

Agreed. Bose usually gets no love from heaphone sites. But, if they are okay with Tyll I figure they are worth a try. So I ordered them. With 30 day return option I guess what do I have to lose, other than background noisesmiley.

The only thing that worries me is the small brick of a power supply that seems so closely tethered to the jack of the iPhone 5s I plan to use. I guess I'll go the velcro route if I decide to keep them.

Argyris's picture

It's nice to see Bose stepping up with the audio quality on their products, especially since that's been the focus of their advertising since forever. Of course they're, oh, about 40 years late on that, but better late than never, I suppose.

I wonder if we can attribute this improvement to pressure from savvy enthusiasts like us (doubtful), or else a general improvement in the sound of headphones across the board against which the company needs to compete (more likely).

I will say this much for Bose. I once tried the QC15 in one of those Best Buy trial kiosk things. The noise cancelling was truly impressive, even if the sound, while not the worst thing I've ever heard, wasn't anything special. If the QC20 improves upon both, then I'd have to say it's potentially a genuinely good product (the more cynical among us perhaps saying that this brings Bose's count for such things up to two devil).

Jazz1's picture

The UPS man just left the Bose on my doorstep about 30 minutes ago. I'd upload a picture (using the selfie mirror trick) of it piggybacked on my iPhone5s. But the power brick wire blocks the camera cheeky.  I'll have to play around with different mounting options. I've got a Lifeproof 5s Nuud case on the way. This might complicate matters. Or I may just use my old Speck case with some 3M tape. I also have a short Shure 9" extension that might help if I want got get really Rube Goldbergish.

Let me say right now that I've got my B&W MM1 desktop speakers blaring lounder than I would normally listen to them. I can't hear a thing coming out of the MM1 speakers. I can feel my desk vibrating, from the speakers, under my hands as I type this This is amazing! I can't hear my typing on the chiclet keyboard.

None of my family is around so I can't test it with real humans speaking. I guess I could get my dog to bark later and see how that goes.

I'm not fond of the sound thump when you put the headphones in the "Aware Mode". Lowering the volume might help, before going into the "Aware Mode", but that two step process pretty much insures you'd miss part of the conversation or announcement. I really have high hopes for these headphones when I fly next.

Comfort is very, very, good!!! Yes it merits three exclaimations. My ears are physically sensitive. Most earbuds are uncomfortable for me. My Ety 4s IEM, sound much better than the Bose, but they are painful for me to use. I also have to lug around a Headroom Headphone Total BitHead with the Etys.

Frankly, the QC20i  is a compromise in sound against my Ets, B&W P5 & P7 headphones. I'm listening to "Congo Square" from Sonny Landreth's Grant Street CD and the drums sound great, as does the guitar. But if I were in a quiet room I'd probably have one of the aforementioned headphones on. But that is the point isn't it? The Bose 20i handily solves the background sound issue. It is, as they say, the right tool for the right job. I'm wondering if I dare hook these up to my desktop rig.

But that compromise in sound seems like it will be extremely worthwhile when flying, or when I'm trying to get a little peace and quiet (so I can listen to my music). The din at my local coffee shops and sandwich shops is horrendous. I love my barristas and sandwich jokeys, but they love to impose their music. Then there is also the wall mounted T.V. blaring along with the speaker music  near my favorite table at Planet Sub (that's the Drake neighborhood for you Bulldogs)

Just think what it going to be like on your next flight when they start allowing people to make mobile phone calls in flightangry. And of course the screaming child in the next row over is going to make the $300.00 for these headphones sound like a bargain.

Whether these are keepers or not only time will tell (30 day return window). My only nitpicks are that the manual and safety manual come folded like a crazy paper road map made for Hobbits. The other gripe is that for $300.00 I would expect an in-wall charging wall wart. Yes you can buy one, but I think it should be included. The included case if nice though.

So when my spouse complains about the price I'm going to tell her I'll be motivated to use the vaccum cleaner. As you know normal earbuds and most headphones don't mix with vaccum cleaners.

Thanks Tyll for having the guts to point out that this Bose is worth it for those of us that deal with noisy environments. I'm going into the holidays with a very useful pair of headphones!

 

 

Tyll Hertsens's picture

Glad you're enjoying them.  Let us know how well they work in the coffee shop. Sorry about your wallet. :)

andyj34's picture

Tyll,

How do the BOSE earphones in your esteemed opinion compare against Shure earphones? 

I presently own a Shure SE535 earphones and I'm planning to buy myself a Shure SE315 for day-to-day commuting. I find once the Shure earphones are properly inserted the noise isolation is awesome. However, that's the problem ... getting a good seal I find to be problematic/fiddly.

Would I better off getting a BOSE?

Andrew

Jazz1's picture

I've not had a chance to try these in the air, or in a car (when I'm a passenger). However, I've also have to make a correction in my original comments. The "thump" only happens when powering them off. I should have read the manual, as the "aware" mode is on the remote. There is no "thump" while operating the headphones in and out of the "aware" mode. So I finally got the benefit of the "aware" mode. It works, but I still have to lower the sound level. This is not hard to do with the in-line remote.

These headphones are so good at blocking out sound my co-workers thought I was yanking their chain when I was ignoring them while they were attempting to  talk to me. I had previously warned them that the these noise reduction headphones were going to block them out. Luckily most of the year I have a private officesmiley.

With no music on, I can hear them speaking, but they sound like they are very, very far away. With music on their voices do not intrude into the music. These headphones came in handy as I spent two weeks in a common area with a lot of conversations going on.

I've also been using them in coffee shops, and sandwich shops and I have found the noise isolation they give well worth the price of these headphones. I've also found them handy around the house when my family wants to watch reality t.v. shows and I need to be in the same room. 

I suppose these are headphones best suited for travelers, or "anti-social" peoplecheeky The sound quality is a compromise if your used to high end equipment. But I don't regret buying them. 

Happy Holidays everyone!

CPT KILO's picture

I'm so greatful for your review on these ear buds Tyll. Being on the pricier side for such tiny ear buds, I held off on the purchase of the Bose QC 20 for many months. I speculated that they would meet my traveling needs but I was dissatisfied with other active noise canceling (NC) cans. Due to my previous experiences with active noise canceling cans, I was skeptical that active NC cans would be of good quality in terms of NC, sound quality (SQ) and build quality. However, due to your review, I took the leap of faith and acquired these buds. I appreciate your reviews on other headphones and obtained a few entry level cans such as the Koss KSC 75, Sennheiser PX 100ii and the Monoprice 8323. The entry level cans I mentioned previously are awesome and each set of cans fit a particular situation very well. However, I needed a set of cans for travel that blocked extremely noisy environments, were portable and had adequate SQ. The Bose QC 20 meet this nitch with ease. I second your recommendation for the Bose QC 20 ear buds and have used them extensively for several months. I love using them in situations where a sense of isolation from outside noise is required ie coffee shops, airplane flights, driving in vehicles and other noisy applications. The QC 20 is a true sanctuary. Thank you again Tyll.

funkypiano's picture

Hi,

No need to again sing praises. We all know these are excellent for noise cancelling on long hauls, sound quality between very good to excellent when NC turned on. Sound quality OK when NC turned off.

The main question, what is the best way you guys have discovered/invented for carrying these with iPad while traveling on subways/underground/tube ?

I have the iPad Mini (retina) which I use for reading and music while commuting to/from work. Modes of transport include walking,underground and overground trains.

The iPad easily goes in and out of my jacket pocket. But with these connected, I can't see them going in and out of jacket/coat pockets without getting damaged.

What do you people recommend ?

Should I velcro them semi-permanent to the back of iPad and hope for a comfortably late onset of damage and expect to get a cheap/free replacement from Bose ?

Thanks,
--

Tyll Hertsens's picture
"Eventually I rummaged through a drawer to find some 3M Command Strips (3M# 17201BLK, available at most stationary and hardware stores) and attached the control module to the back of my Otterbox Defender case wrapped Galaxy S3 phone."
funkypiano's picture

Hi Tyll,
Thanks for pointing that out :)

Also, would you consider/recommend using something like Sony SBH20 to "loosely couple" the QC20 to iPad ?

Thanks,
--

funkypiano's picture

Hi,

I actually tried a Nokia BH-121 Bluetooth unit paired with both Lumia 920 and iPad.

The sound quality is no worse then QC20 plugged in directly to the device.

The convenience is that I no longer worry about damaging the QC20 due to the free floating battery unit on them. They just stay in one of my pockets. I either have convenient access to the Phone, iPad OR the Blutooth Unit controls itself.

Just my £0.60 in case it helps :)

--

mark's picture

Hi,

Thanks a lot for the great review.

I easily get pain and inflammation in my ear canals and as a result can't use in-ear monitors normally. So I use either on/around ear phones or earbuds. The problem is when traveling I prefer to not have large on/around phones, but earbuds let way too much noise in. So, I am considering either custom in-ear monitors, or the QC20.

Does anyone have an opinion/guess on which would be less irritating for the ear canal between the QC20 or custom fitted in-ear monitors?

Thanks!

Tyll Hertsens's picture
I'd say the QC20 would be the thing to try. The tips really don't go in your ears, but rather rest up against them. Quite comfortable actually. CIEMs will be somewhat like regular IEMs.
q's picture

Tyll,

Have you had a chance to try the Harmon Kardon noise cancellers? I hear they aren't too bad.

Cheers,

q

adasam's picture

Hi, what size command strips did you get? I cannot see the dimensions anywhere on 3M website and they sell 3 different sizes...

Thanks a lot !

ahaywood's picture

How is the sound quality compared to the Parrot Zik?

For that matter, sound quality is by far the most important quality, with ability to cancel sound when on the train, or in the office being a distant second, anything else other than one of these two that would do that well?

Thanks.

CHPrice's picture

I live in NYC and ride the subway every day. I currently have a pair of Shure SE215. They are great but everyone has been raving about the QC15 and QC20 so much I thought I would give them a try. I thought they were both terrible. Neither of them provided the isolation that I had hoped. In fact, they were nowhere close to as good as the memory foam ear tips I use on my Shure. When you first turn on the noise cancelation, it seems like this sudden amazing hush. It did a great job of quieting the sound of the air conditioning on the train. But I had to crank the volume all the way to the top to be able to hear over the general talking on the subway, including the announcer at every station. On the platform, there was nothing I could do. I simply had to stop my recording and wait to get on the train. I could not hear anything over the noise of the trains pulling in and out of the station. Or babies crying. I am primarily listening to podcasts of people talking. I found with both the earbud and over ear versions, the environmental noise made it hard to understand the dialogue. I am now considering CIEM versions in the hope that I can finally get some true isolation.

benjdbs's picture

Like Jimmy01, I'd also like to match the qc20 w/ the 391s. I currently use this pair (the 391s) since nov. 2013. Most reviews over the 'net were pretty much accurate including occasional sibilance (not all the time, source dependence...). Its strongest point is in the percussion, very fast, agile and if there's bass, it'll play. Concerning the NC from the 391s, they're weak compared to the '20s, so they say. My priority has always been sound quality, then the noise canceling comes next. I will be upgrading very soon. I do hope Bose can match up, SQ wise. We hope you could give us your feedback. Thanks, [Source: HTC 1x+, Asus JV550 16gb, File types, FLAC,WAV,CD, SACD, Bluray, HD tracks]

PierPaoloG's picture

Hi Tyll, most reviewers say that the Noise Canceling properties of the QC25 is better than the Qc20i ones. I have tested them in a bose store and I think that the QC20i is WAY more effective. Maybe that reviewers have not perfectly chose the ear tips....May you please clarify your opinion?
Thank You

JamesFreedman's picture

I was all set to buy one of these until I found out you can not replace the battery! You kind of glossed over this in your article, but I think it is a big deal we should all pay attention to.

Anybody who has worked with computers for awhile (laptops, UPS, etc) knows that "expected" battery life is far from actual. Sometime batteries wear out very quickly, other times they far exceed expectations.

Sorry, but hanging a $300 set of headphones on a $20 battery...nope! Bose shouldn't have cheaped out on this point.

Rawan's picture

Thanks for the review! I'm wondering; would these work on continuous power, i.e., when plugged in to a battery pack for example? The comment submitted by JamesFreedman mirrors my exact concern; these are $300 earphones, and sooner or later, batteries do get to a point where they no longer hold a charge. Yes, these can be still be used without NC, but it beats the point of having them, especially that (in passive mode) there are much better sounding earphones for much less than $300.

So I'm thinking, when that happens, would they work if plugged into a battery pack? It's not ideal to have a battery pack dangling, but hey, it might be reassuring that when the lithium batteries do die, we could still use the NC as long as it's plugged into a power source. Doable you think?

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