A Better Traveler's Sanctuary: The Bose Quiet Comfort 25 Measurements

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

Raw frequency respons plots for the QC25 show very stable bass response with positional changes, but oddly some significant differences in the region between 1kHz and 3kHz. I'm not sure what to make of this exactly, but note the rise in distortion in the same area. I suspect that the noise canceling circuits are reaching the frequencies at which noise canceling becomes difficult and various anomolies begin to appear.

Compensated FR plot shows a mild warm tilt, and very good overall linearity to 3kHz. Very few passive headphones are able to remain linear in the 800Hz to 3kHz region, and to my ears I felt the tonal balance was very good as a result. Above 3kHz it's a bit of a bumpy ride down hill, but this falling response above 3kHz is similar to that of the Harman response curve and should probably be considered close to neutral.

30Hz square wave has reasonable good shape compared to most headphones, but compared to many noise canceling headphones it's simply extraordinary. Most noise cancelers make an unholy mess out of 30Hz square waves; that the QC25 looks almost normal is a very pleasant surprise. Between the slight rise in the bass, good 30Hz square wave shape, and relatively low distortion in the bass, you'd think these cans do a lovely job delivering punch down low...and they do indeed.

300Hz square wave has some visually disturbing ringing, but I've come to think this 3kHz ring is strongly related to the first resonant mode between the driver and eardrum, and is less troublesome in listening than one might surmise from the 300Hz square wave. Many headphones exhibit this (Senn HD 600, Focal Spirit Pro, Skullcandy Aviator) and in my experience the result is a slight 'lithpyness' to the sound. The QC25 has this feature a bit more prominently than the other headphones mentioned, and it does seem they have that 'th' instead of 's' character a bit more strongly than those other cans as well. Fortunately, this type of error doesn't create any grating harshness or edginess, and as a result tends to be relatively benign. This is also seen strongly in the impulse response, but other than this feature the impulse response is fairly clean.

As mentioned before, THD+noise shows a significant rise in distortion between 1.5kHz and 3.5kHz, probably leading to my conclusion that this headphone is good mid-fi and does not have the finesse of true high-end headphones...and frankly, I doubt we'll see that in noise cancelers for a long time to come.

Impedance and phase response are somewhat irrelevant as we're looking at the input to an electronic circuit rather than a headphone driver.

Isolation shows excellent noise reduction across the board with -26dBspl attenuation broad band.

With 72mVrms needed to achieve 90dBspl at the ear, this headphone will play to solid listening levels with portable devices.

Measurements in Passive Mode

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

I'll not analyze these measurements fully, but will point out a few things:

Frequency response is significantly uneven showing just how much DSP correction is being done to the headphones when in active mode.

Impedance and phase response measurements indicate to me that capacitive coupling remains in place when in passive mode.

Bose Corporation
The Mountain
Framingham, MA 01701

tony's picture

Hello Tyll ,

Is that the only clue you will give to the amount of reduction in noise , what is the total reduction in Noise ? .

I wear the little yellow plugs when I travel and am now considering a pair of these QC 15 or 25 . I wouldn't be using the cord so it's good to see you removing it to install in the case .

I would use an iem or ciem with the QCs , the idea would be to lower ambient noise level .

Looks like you're having a White-out Snow Storm from the looks of your Window , hope your snow blower is tuned up .

Tony in Michigan

ps , I checked the Bose site , love the colors , no db reduction quoted or promised , what gives ?

Tyll Hertsens's picture
Sorry, I assumed people would read the measurement page and I shouldn't do that. Broadband attenuation (100Hz to 10kHz) was 26dB for the QC15, 26dB for the QC20, and 28dB for the QC25.

Thanks, I should have mentioned that.

tony's picture

I did read the measurement page , I enlarged it on my iMac , the lettering seems blurry and I wasn't sure what I was seeing . Thanks for explaining , that 28 db is important , perhaps the most important part of the product . I don't see it as an advantage over the Etymotic or the yellow plugs unless a person wear them over the Etymotic or yellow plugs yielding a total of 50-60 db .
I do fly in Small single Cessna and Beach Aircraft equipped with Canceling Headphones , Canceling phones work but I wouldn't want to live with them , I'm in a hurry to take them off when we finally arrive , they're quite horrible without horrible noise to contend with , the flying noise ruins flying as a hobby .
We live in a noisy World , sometimes we can't get around being surrounded with high ambient noise levels , it seems a tense time , even with sound protection .
I'll take Walden's Pond with its Frogs croaking .

Thank you for being helpful

Tony in Michigan

ps . Bose won't quote their measurements , your the only one willing to whisper the real number , hope you don't get in trouble for it !

Limp's picture

The graphs are vectorized (PDF), you really shouldn't see any blur if you do things right, viz. clicking the preview and then zoom.
Tyll could probably make the previews a tad more readable (and reduce file size) if he exported them as PNGs. Seeing jpeg compression applied to nice flat graphics like that makes the graphical designer in me cry a little every time.

Impulse's picture

I wonder if a lot of people don't realize they're clickable PDFs and/or if that contributes at all to many ignoring the measurements page (as per Tyl's own stats)... More than likely it's a general aversion to numbers and the fact that they're placed last AFTER the review conclusion, still tho, I agree it'd be better presented if he changed the preview as you suggest.

zobel's picture

Heard anything about progress there?

Impulse's picture

I think they reached a settlement a few days ago, I remember reading a news article about it... I doubt we'll be privy to any details on the actual settlement or reasons for it.

Eli's picture

Thanks for the review Tyll!

I think you forgot to mention one other (important) incremental improvement of the QC 25 which is the reduced hissing noise produced by the headphones. Bose speaks about this and I also verified it in a store. It was quite a big difference between the QC15 and QC25.

bernardperu's picture

Tyll, so oN a jet airplane...what combo would give me more musical pleasure for well recorded hi-rez music?...let's say i am listening to Mingus...1) ak240+focal classic or 2) bose qc25 + the best dap that matches it.

How much noise is it necessary for me to dump my best dap + my best noise isolating phones in order to upgrade to the Boses? Does it require standing right next to a construction site?

By the way. I travel a lot. Best solution for noise while enjoying music i use is mad dogs + hifi m8.

Tyll Hertsens's picture
I'd take the Bose over the Focal on an airplane, the Focal just won't secret you away from the noise.

75-80dBspl, I'm guessing. Airplanes, trains, noisy bars, room full of servers. I recon if you're in a loud environment you'll know it.

Mad Dogs isolate quite well, Alpha Dogs even better.

bernardperu's picture

ThAnKs for the reply!

My fiio x5 + focal classics allow me to engage in the music while being on an airplane with no need to multitask; just listening...

Perhpas, Tyll, you could be more specific about the qc25s: are they good enough for conscious listening? Or good enough for listening while multitasking? So they are good at cancelling noise while music is the background to something else? Can they make music engaging and non-fatiguing?

Tyll Hertsens's picture
Is it best to meditate on a bed of nails or a lay-Z-Boy chair? Some might argue convincingly that the bed of nails is better.

What I'm saying is that musical engagement is fundamentally about state of mind rather than fidelity of reproduction. But I will say that I find the QC25 plenty good at delivering music well enough to enjoy, and they are definitely non-fatiguing to my ears.

bernardperu's picture

"musical engagement is fundamentally about state of mind rather than fidelity of reproduction."

Those are very wise words. So if it all comes down to our state of minds, why don't you elaborate more on this and write Think Pieces on your philosophical approach to musical engagement?

I bet many of your readers would appreciate a large dose of "Philosophical Tyll."

In my opinion, Hi-End publications desperately need more Think Pieces. The state of mind you are referring to does not necessarily reside in each individual gene pool, but it is more a product of modern trends. More exploration on this matter is highly welcome.

Tyll Hertsens's picture
....well, I do have a whole schtick about, "Is the appreciation of the art of music directly related to the fidelity of reproduction?", which is where that statement about the bed of nails comes from. Okay, I'll think bout writing that one up one of these days.
bernardperu's picture

Excellent! You have a way of capturing readers' attention so you are likely to have tons of comments for this Think Piece.

Not long ago I read that you wanted feedback from InnerFidelitytes on how you could improve the impact of your online based media platform. In my opinion, Think Pieces can create a lot of valuable broad attention.

DiRo's picture

Hi Tyll thanks for another great review. I am wondering if you can elaborate just slightly on your definition of "mid fi". As some people consider HD600 as mid fi others may use M50s as an example.

I currently have SRH840 for just run around headphone, would you say sonic wise QC25 is same class give or take...or? Thanks!

Tyll Hertsens's picture
I'd characterize the HD600 as more entry to mid level high-end...they're very good.

M50s and SRH840 would be mid-fi, thing is, there's all sorts of ways to fall short. The 840 might not be neutral enough, the M50 maybe lacks transient resolution. The QC25 is surprisingly neutral, but the artificial treble keeps it from being more than good mid-fi, IMO.

DiRo's picture

If I may one more question relating to "Wall of Fame".

Been following your articles and wall of fame... D2000 got bumped by K550, it self then got bumped by UE600< Momentum< HP50. 4 revamps later, is the HP50 incrementally better than K550? Or HP50 is leep and bounds better in sound quality than K550, now K550 has been lapped 4x on the wall. Somewhat ironic in that both headphones is going for the "open" sound.

Noted your review of K550 stated it's better than SRH840. But don't think I can make the inference "If QC25 is in same class as SRH840, then sonically K550 is better than QC25." Or can I make such an inference?

Simply **my purchase decision is stuck between K550 and QC25. Currently own Shure SE425, SRH1540, 840, HD600, HD25. Like them all but wouldn't say I like lay back or warm sound as I sold my Momentum, just wasn't happy with the sound signature.

HugoQueiroz's picture

Hi there Tyll, I really hope you can help me out with this one.
Right now, in my laptop bag, I carry around 3 different headphones every day to work. Plantonics for conferences, Klipsch One Premium for music\movies and a small Monster Purity In-ear for whenever I’m listening to my cellphone. So, as it turns out, too much stuff to carry around and I really would like to find the best solution to only use one headphone.
My desired budget for this is around $300, it must have a mic (so I can join conferences if I have to), and it must have some level of portability\durability, since I travel a lot.
I’ve never used Noise Cancelling, so not sure how useful that would be, but I do fly a lot…
Right now I was thinking of a few options, I would to hear your opinion: Bose QuietComfort 25, V-Moda M100, V-Moda XS, Sony MDR-1R, but that’s just what it came to my mind…

Tyll Hertsens's picture
You may want to give the Focal Spirit Professional or NAD VISO HP50. Both have some fit oddities, so you should see if you can find a place to try them on, but both are also better sounding than the cans you mention, IMO. If you fly a lot, the QC25 might be the way to go, the other cans won't isolate nearly as well.
mvyrmnd's picture

Hi, and thanks for the awesome website!

I had a pair of QC15's that my 2yo made short work of one fateful morning - and upon closer inspection was sorely disappointed with the strength of the cup rotation mechanism - it was (in aussie vernacular) piss weak, a very small amount of plastic was doing all the work. Have they improved the design any on the QC25? What material is the primary structure of the folding made of?

PS. It was on the strength of your review that I replaced the broken QC15's with a pair of Fidelio L1's I got on a end-of-model runout sale. Now these are headphones that are made properly!

Tyll Hertsens's picture
The folding mechanism on the QC25 is cast zinc, so I think it is an improved design.
blueangel2323's picture

Tyll, how do the QC25 compare to the QC20? I know it's hard to compare between over-ear and in-ear, but the QC20 sounds pretty neutral to me, and far superior to the QC15 which seems very harsh in the treble. Not bright, just harsh as in very peaky, gritty, un-smooth. The QC20 doesn't have this problem as the treble is pretty much perfect below 10k (but lacks extension beyond that). Thanks

Thorz's picture

Hello Tyll.
I have read your review on the QC20s and you write marvels about them telling also that they are a big improvement over the QC15.
In this review of the Q25s you say that they have improve a little bit over the Q15.
How do you compare the sound quality between the Q20 and the Q25? I am specially interested in the bass quality.

blueangel2323's picture

I have both now, and Tyll is right when he says that everything is slightly improved on the QC25 over the QC15... which unfortunately means that they still don't sound as good as the QC20. The QC20 is much flatter in the treble region, whereas the QC25's treble is still peaky and artificial sounding, albeit not as bad as the treble on the QC15.

Thorz's picture

Thanks. How about the bass? Have read on some places that the bass is better on the Q25 compared with the Q20.

blueangel2323's picture

Yes, the bass is the best aspect of the QC25's sound. QC15's bass was flabbier in comparison. QC25's bass is tight but very powerful. Kinda reminds me of B&W P7's bass actually.

Thorz's picture

Thanks again, you have been very helpful. I think that I will order the QC25 and take them for a spin. If I am not satisfied I can return them and go for their sibling.

dp's picture

I take them with me whenever I travel. I use them on airplanes and in hotel rooms to tune out noisy ac or snoring roommate.

They are also the most comfortable headphones. I travel often between US and Asia. QC15/25 are the ones that I can wear for 13 hours or more straight.

thonglor16's picture

I purchased the QC25s in triple black recently and they look gorgeous.

They seem quite durable, although I wouldn't want to really test them.

The noise cancelling abilities are really second to none. I didn't own the QC15s so can't really compare.

If you're sitting on the fence about these, don't.

Grab them while the triple black is still available!

They rave about them here

Phryq's picture

Thanks so much for this review Tyll!

I currently own the QC 25s. I use them for composing / mixing samples music, for example on my website AlbertMcKay.com

Some people tell me noise-cancellation is really bad for mixing. I'm thinking I should get a set of AKG 702s. Do I really need this? Or am I ok with the QC25s? For example, I might have difficulty hearing balance / reverb. But maybe it's only my hearing ability, and not the headphones' fault.