Bose QuietComfort 45 Headphone Review

[Robbo99999]

Let's start with the fact that they did implement channel matching up to 1 kHz and very tightly so. Question is, whey did they not take it to 3 khz. @Robbo99999 may be onto something: if pad variations were large in their factory jig, that would be the reason they didn't think they could reliably EQ to match in that region and left it alone. Based on my subjective testing, which very likely they performed too, this was a non issue so they have gone with it. I think they deserve praise for locking the two channels so well up to 1 kHz. And with appropriate bass boost. This is most of the game and they got it perfectly (and consider the very low distortion as well).

There's also the idea that if they cut off their EQ control at a certain point then there are still the effects of their automatic EQ parametric filters beyond the cut-off point - which might mean that the area directly above the cut off could be obscenely messed up because it's being locally affected by the variable/unpredictable automatic EQ that is happening just below the cut off frequency.....so that could compound areas directly above the cut-off point & up until you get high enough in frequency that the "hangover" effect of the EQ is no longer taking place, so controlling the frequency below a certain frequency will make that area better, but immediately & directly above the cut-off frequency it could compound/amplify existing frequency response errors shortly above the cutoff point. I've only just thought of that idea. (As we know parametric filters have a Q value and that width affects stuff beyond their stipulated frequency, and especially if a number of them are being combined into a potentially aggressive overall total summed EQ curve - so it can potentially affect the frequency response locally above the EQ Cut-Off Point of this headphone - and it would be in unpredictable ways, because it's not being controlled nor measured by the headphone beyond that point)

(That idea doesn't remove the idea of the pads being one of the variables contributing to channel matching issues through the frequency range).

 

[JohnBooty]

My takeaway is that most people using this will never be using it in passive mode

I think this is mostly true.

Passive mode (which not all noise-canceling headphones have!) is a huuuuuuuuuge lifesaver when your battery has run out of juice. It's like a spare tire in your car. It kind of sucks, and nobody wants to use it, but you may definitely appreciate it someday.

 

[Helicopter]

I think this is mostly true.

Passive mode (which not all noise-canceling headphones have!) is a huuuuuuuuuge lifesaver when your battery has run out of juice. It's like a spare tire in your car. It kind of sucks, and nobody wants to use it, but you may definitely appreciate it someday.

And they could have saved a buck if they had made it BT-only with nothing but a charge port and an antenna.

 

[617]

I think this is mostly true.

Passive mode (which not all noise-canceling headphones have!) is a huuuuuuuuuge lifesaver when your battery has run out of juice. It's like a spare tire in your car. It kind of sucks, and nobody wants to use it, but you may definitely appreciate it someday.

I wouldn't be surprised if a lot of people buy these and don't even use them for music - just phone calls, reducing environmental noise, watching youtube videos on the train and so forth.

I just ordered a pair of WH-1000Xm4. I'll be sure to do a full breakdown vs the 6xx or whatever sennheisers I have.

 

[markanini]

I just ordered a pair of WH-1000Xm4. I'll be sure to do a full breakdown vs the 6xx or whatever sennheisers I have.

Going by measurements you should have ordered the Bose for ANC. (Sony WH-1000Xm4 - Bose QC45)

 

[MayaTlab]

The channel imbalance is not due to low quality drivers. Modern drivers generally don't have 6db variations in their piston region.

The channel imbalance is due to the wildly different acoustic context between the side cups (my opinion anyway). One side of the headphone has a pcb with some little mics attached, but the other side has that with a lithium polymer battery as well. This takes up a lot of volume.

Bose (and many other companies) have for a while designed their closed back headphones with a third volume around the rear volume, where the electronics sit : https://www.52audio.com/archives/94914.html
It doesn't guarantee that the front and rear volumes are perfectly mirrored between each sides but I believe that it minimises the issue.

Certainly for some headphone earpads the variation is certainly not dialed in properly, which was the point I brought up that pad variation can affect 1-3kHz in some instances. As you originally said, the variation that can be seen in a headphone is more than just the variation of it's driver component. As for the extent of other tolerances within the manufacturing & assembly process I cannot be certain, but I'm certain that some variation would exist, how big that variation I don't know, and it's likely different dependant on the starting "design variance susceptibility" of any given headphone model (some design models are gonna be more difficult to manufacture to tight tolerances in both production of it's individual parts & the assembly of those parts) combined with the willingness/ability of the manufacturer to commit to assembling it and controlling it properly with Q&A, etc, all of which has cost implications.

I am not certain that this is a sign of poorer tolerancing per se, but rather as a design issue first, the headphones being designed in a way that makes them highly susceptible to vary because of minute variations above around 1kHz, either manufacturing or assembly tolerances (including earpads, and even including how the earpads are assembled onto the earcups for specific units, for the Bose QC25/35/45 this is a frequent issue given the attachment mechanism), or coupling.

@Thomas_A already provided a link to this post in that thread, perhaps it's a good idea to re-post it : https://audiosciencereview.com/foru...250-ohm-bose-qc25-measured.32622/post-1164980
I'd be careful interpreting the data past 1kHz because of the method used, even more so past 4-5kHz, but I do think that the inter-individual variance shown for the QC25 (not quite the same acoustic design as the QC45 but most of the design has been carried over in the QC series) around 2-3kHz can't be explained by a methodological issue alone in light of the other measurements. I've also found them highly susceptible to pad compression variation past 1kHz or so, regardless of whether the DSP is enabled or not (examples in that same thread with both ANC on and off).

I don't know why Bose's (and quite a few other ANC over-ears) would be designed in a way that seems to results in a high sensitivity to coupling and / or tolerancing issues past 1kHz, but I'm wondering, looking at Bose's patents, if the way these headphones are vented, which in the case of Bose, follows a rather specific recipe, could be the culprit. In which case this would simply be a negative byproduct of a deliberate attempt to maximise performances in other areas. I guess that this is where notions of acoustic impedance / reactance / resistance come into play, but I'll leave it to people who actually understand them (not me !) .

There's also the idea that if they cut off their EQ control at a certain point then there are still the effects of their automatic EQ parametric filters beyond the cut-off point - which might mean that the area directly above the cut off could be obscenely messed up because it's being locally affected by the variable/unpredictable automatic EQ that is happening just below the cut off frequency.....so that could compound areas directly above the cut-off point & up until you get high enough in frequency that the "hangover" effect of the EQ is no longer taking place, so controlling the frequency below a certain frequency will make that area better, but immediately & directly above the cut-off frequency it could compound/amplify existing frequency response errors shortly above the cutoff point. I've only just thought of that idea. (As we know parametric filters have a Q value and that width affects stuff beyond their stipulated frequency, and especially if a number of them are being combined into a potentially aggressive overall total summed EQ curve - so it can potentially affect the frequency response locally above the EQ Cut-Off Point of this headphone - and it would be in unpredictable ways, because it's not being controlled nor measured by the headphone beyond that point)

(That idea doesn't remove the idea of the pads being one of the variables contributing to channel matching issues through the frequency range).

I've seen situations where feedback systems can result in an "overshoot" or "undershoot" in the transition zone between the zone where they operate and above, if they respectively have to lower the SPL more than anticipated (overshoot) or raise it more than anticipated (undershoot). But I don't think that this explains the behaviour of the QC45 above 1kHz or so (cf Thomas' thread) as pad compression tests when the DSP is off show the same variability.

Let's start with the fact that they did implement channel matching up to 1 kHz and very tightly so. Question is, whey did they not take it to 3 khz.

"Classic" feedback systems can't operate past 800-1k Hz.

 

[Jimbob54]

I wouldn't be surprised if a lot of people buy these and don't even use them for music - just phone calls, reducing environmental noise, watching youtube videos on the train and so forth.

I just ordered a pair of WH-1000Xm4. I'll be sure to do a full breakdown vs the 6xx or whatever sennheisers I have.

I had a pair of the XM3, I just couldnt use them because they mic'd up a click/ rub in the frame when I walked with the ANC on. Hope the 4s dont suffer from such.

 

[amirm]

"Classic" feedback systems can't operate past 800-1k Hz.

What feedback? I am not talking about ANC.

 

[Robbo99999]

I am not certain that this is a sign of poorer tolerancing per se, but rather as a design issue first, the headphones being designed in a way that makes them highly susceptible to vary because of minute variations above around 1kHz, either manufacturing or assembly tolerances (including earpads, and even including how the earpads are assembled onto the earcups for specific units, for the Bose QC25/35/45 this is a frequent issue given the attachment mechanism), or coupling.

@Thomas_A already provided a link to this post in that thread, perhaps it's a good idea to re-post it : https://audiosciencereview.com/foru...250-ohm-bose-qc25-measured.32622/post-1164980
I'd be careful interpreting the data past 1kHz because of the method used, even more so past 4-5kHz, but I do think that the inter-individual variance shown for the QC25 (not quite the same acoustic design as the QC45 but most of the design has been carried over in the QC series) around 2-3kHz can't be explained by a methodological issue alone in light of the other measurements. I've also found them highly susceptible to pad compression variation past 1kHz or so, regardless of whether the DSP is enabled or not (examples in that same thread with both ANC on and off).

I don't know why Bose's (and quite a few other ANC over-ears) would be designed in a way that seems to results in a high sensitivity to coupling and / or tolerancing issues past 1kHz, but I'm wondering, looking at Bose's patents, if the way these headphones are vented, which in the case of Bose, follows a rather specific recipe, could be the culprit. In which case this would simply be a negative byproduct of a deliberate attempt to maximise performances in other areas. I guess that this is where notions of acoustic impedance / reactance / resistance come into play, but I'll leave it to people who actually understand them (not me !) .

Yep, I agree, we're basically saying the same thing.

I've seen situations where feedback systems can result in an "overshoot" or "undershoot" in the transition zone between the zone where they operate and above, if they respectively have to lower the SPL more than anticipated (overshoot) or raise it more than anticipated (undershoot). But I don't think that this explains the behaviour of the QC45 above 1kHz or so (cf Thomas' thread) as pad compression tests when the DSP is off show the same variability.

Yes, that is indeed what I was saying re "overshoot" / "undershoot", it's a good way to describe it. So you think it's the pads rather than any EQ overshoot/undershoot, fair enough, and it aligns with my measurements (on other headphones) that pads can affect the 1-3kHz area; either way I think it's a pretty poor trait in this reviewed headphone, I did mark it down in the vote for that quite substantially, that channel matching is not good.

 

[IAtaman]

What feedback? I am not talking about ANC.

L and R are all over the place when the device is off, and almost stick to each other up to ca 1KHz when the device is on so presumeably its is DSP circuitry that does the matching?

 

[MayaTlab]

What feedback? I am not talking about ANC.

It’s the feedback system from the ANC that is also responsible for the channel matching below 1kHz when they’re turned on (and the low inter-individual variation in that range).

 

[Dennis_FL]

We often talk about inaudible noise levels at -115 dB.

I had a subwoofer repaired and I was redoing my room correction when I noticed my background noise was coming in at 55dB --- probably the air conditioner, air vents, street noise, computer noise (hard drives), washing machine, wife, dog, etc. I went around the house turning things off and it didn't help much.

Then I put on my Bose headphones with ANC and it is truly amazing how quiet it gets with zero source. Wow!!!

Last week we flew overseas and instead of headphones I took my first gen Apple Airpod Pro's and they didn't cancel the jet engine noise very well. Next time it's headphones.

 

[JohnBooty]

And they could have saved a buck if they had made it BT-only with nothing but a charge port and an antenna.

Yeah. And you just know that comes up every single time they design a headphone and are (as with any product design in any industry) attempting to trim pennies and cents off of the production costs.

It would be an easy thing to omit and most people never use it. So, I really appreciate that they have stuck with it.

Last week we flew overseas and instead of headphones I took my first gen Apple Airpod Pro's and they didn't cancel the jet engine noise very well. Next time it's headphones.

Once, my wife and I were on a 7-hour flight with a screaming baby nearby. I am talking seven straight hours of literal screaming and wailing. We had only a single pair of NC headphones between us.

I tell you man, the airline lost out on a LOT of money that day. They really should make NC headphones available for inflight purchase. They might have sold 100 pairs that day, at a decent markup too.

(It wasn't some kind of misbehavior or bad parenting.... the poor thing had an ear infection or something and there was nothing the momma could do. Wasn't anybody's fault)

 

[617]

Going by measurements you should have ordered the Bose for ANC. (Sony WH-1000Xm4 - Bose QC45)
View attachment 300348

I'm going to EQ them. The Sony have a few features which sold me, the gestures and app and all that jazz. Both look like very good products however. I'm only getting them because my excellent Razer Opuses broke. Might try to fix them.

 

[Human Bass]

14ms is a really low delay, less than one frame in 60fps

 

[perdido34]

Yeah. And you just know that comes up every single time they design a headphone and are (as with any product design in any industry) attempting to trim pennies and cents off of the production costs.

It would be an easy thing to omit and most people never use it. So, I really appreciate that they have stuck with it.

Once, my wife and I were on a 7-hour flight with a screaming baby nearby. I am talking seven straight hours of literal screaming and wailing. We had only a single pair of NC headphones between us.

I tell you man, the airline lost out on a LOT of money that day. They really should make NC headphones available for inflight purchase. They might have sold 100 pairs that day, at a decent markup too.

(It wasn't some kind of misbehavior or bad parenting.... the poor thing had an ear infection or something and there was nothing the momma could do. Wasn't anybody's fault)

I've never had the misfortune of being on a plane with my ANC headphones and a screaming baby. How much did the ANC headphones suppress the sound?

 

[Morpheus]

I have no problem spending $400 on Sennheiser HD600s or whatever because I have a pair of 580s which I bought in the late 90s which would still be working if I could get a new driver for them (which they sold for decades.) Realistically a pair of $400 headphones could last 15 years - $26 dollars a year. Meanwhile my Razer Opus, which were fantastic headphones, just died and it's going in the bin unless I can maybe put a new battery in it. So, I expect them to last 3 or 4 years - $50 - $100 a year.

Completely agree on this. Actually I would encourage everybody in this forum to lobby against the ways of the industry on active headphones, for some progress on that matter.
Bluetooth and ANC headphones are a sustainability/environment and consumer rights disaster. How can we go on basically keep manufacturing this high tech and expensive products like disposable items, and perpetuate, or even acentuate the issues that brought us to the climate change/pollution issues we are responsible for? Not only you are condemned to throw them away in just a couple of years for lack of long term reliability and battery degradation issues, but brands make them conveniently unserviceable and unrepearable or outlandlishly expensivly so, and don't provide long-term support at all. At the very least, the batteries should have some kind of minimum standardisation in a couple of really smal size formats ( like the pill-like ones in watches) so as to be easily swapable/replaceable. I am no Luddite, and use this phones too: in my household we have Sony's XM1000II and WF1000XM4, Samsung Buds 2, and SPC Zion ( already 2 pairs died just after 2 years). But my 6XX And 800S Sennheisers are a lifetime investment in every sense and environmentally friendlier in every way...Even when you only take cost into account, I wonder how many pairs of quality bluetooth/ANC will I have to go through over the years and its total cost if nothing changes...Big volume sellers ( Sony, Bose, Sennheiser,Beats) have environmental responsibility and should foster a change. Call it Utopia, but I wonder how many of you would pay say, 30% extra, to be sure that your 100$ buds would have available and cheap replacement batteries for ay the very least 10-12years, instead of ending in the dumpster after 2 or 3.

 

[JohnBooty]

I've never had the misfortune of being on a plane with my ANC headphones and a screaming baby. How much did the ANC headphones suppress the sound?

Pretty well, if I had music or white noise playing. Was no big deal at that point.

Armchair analysis: ANC is most effective at blocking lower frequencies. Obviously, a baby's scream is more mids and highs. But, there were a few rows of seats between me and the poor lil guy. So I'm sure those were attenuating some of the higher frequencies.

Armchair analysis disclaimer: It is entirely possible I have no idea what I'm talking about.

Unfortunately I couldn't really relax even with ANC because my wife was still actively suffering, lol. (We took turns with the headphones)

 

[Pretorious]

We often talk about inaudible noise levels at -115 dB.

I had a subwoofer repaired and I was redoing my room correction when I noticed my background noise was coming in at 55dB --- probably the air conditioner, air vents, street noise, computer noise (hard drives), washing machine, wife, dog, etc. I went around the house turning things off and it didn't help much.

Then I put on my Bose headphones with ANC and it is truly amazing how quiet it gets with zero source. Wow!!!

Last week we flew overseas and instead of headphones I took my first gen Apple Airpod Pro's and they didn't cancel the jet engine noise very well. Next time it's headphones.

I agree, and want to stick my several cents in. Perhaps these are simple points that have been missed in this thread.

The basic background noise of a modern home can be quite annoying, In my opinion, and as you mentioned, HVAC, street noise, appliances, wind, cars, aircraft, spouse/children, pets, landscapers, workers, are only some of the many things that contribute to the endless assault of noise we hear daily. It's the main reason I can't enjoy my main hi-fi system: as soon as the vents start blasting air, that's just about it for my tolerance of background noise, not to mention all the rest.

It's incredible. I didn't realize how much noise there was until I bought a pair of these very same headphones in this thread and put them on. It was life-changing. I can even have a fan blowing right on me during these summer months and never hear the thing. Before, it was a choice between audio quality (wearing my HD 600) or being cool. Combine this with the accurate frequency response and it truly is a great product. As @617 mentioned:

If an audiophile brand created a product which attenuated all room noise, your neighbors, your dishwasher, the guy running his leaf blower, by 30db, and replaced it with a dull whooshing noise that was imperceptible when music was playing, it would be considered the greatest hifi product ever invented.

And I concur, which is why I voted 'great'. It has almost single-handedly changed my perspective on consumer audio and what audiophiles say about Bose. There is a lot of scientific research going on in these non-traditional hi-fi companies and they are making quality, accurate products for the masses. I like not having to spend a fortune to get accurate audio. I like convenience, too. It's nice to have both.

For those interested, I was listening to Kind of Blue last night with these headphones and the tape hiss was louder than any hiss from the ANC circuit. So if you can stomach tape hiss in old recordings, especially pre Dolby-A, then I don't see how this would bother you.

 

[Robbo99999]

14ms is a really low delay, less than one frame in 60fps

Considering human visual reaction time is in the region of 200ms and less, and human auditory reaction time is even less than that, then 14ms as part of your "reaction chain" could be pretty significant when reacting to auditory cues in fps "competitive type" gaming environment. So a gamer wouldn't really want a 14ms delay on their audio, they'd rather choose a different headphone.