标签: headphones

Do you remember my blog from a couple of months ago, Check this out: Really annoying music suppressors , about my desire to find some effective way of preserving my sanity whilst driving in the car with my wife, Gina the Gorgeous, who is partial to Christian rock and who likes her music on the loud side of things? The real problem comes when we are on a long journey, such as an 8.5-hour road trip to Louisiana to visit Gina's mom.   I've tried using my MDR-NC500D digital noise-cancelling headphones from Sony. When I turn on the noise cancellation, however, although the rumble from the ground almost completely disappears, they have no effect whatsoever on the music. Much to my disgruntlement, in fact, the end result is to make the songs Gina is playing sound clearer and -- paradoxically -- louder.   MDR-NC500D digital noise-cancelling headphones from Sony.   After our most recent trip to Louisiana, I started cogitating furiously. There had to be some solution to this dilemma. Eventually, I came across a pair of 3M Peltor H10A Optime 105 Earmuffs from Amazon, which weigh in at 12.3 ounces, have an NRR (noise reduction rating) of 30dB, and are an absolute bargain at only ~$21. However, I actually ended up purchasing a pair of 3M Peltor X5A Earmuffs as illustrated below.     3M Peltor X5A Earmuffs.   These little rascals are a tad more expensive at $25.92, but their claim to fame is that they boast an NRR of 31dB. All I can say is that when it comes to my listening to Christian rock, every extra dB of noise reduction is worth its weight in gold.   Happily, I can easily wear my iPad earbuds under these ear muffs. I've given them a test drive in our family room while Gina is watching dross on television like Dance Moms or 19 Kids and Counting and they work incredibly well in that environment -- I literally can't hear a thing from the outside world, even if my iPad isn't playing anything.   My next thought was to wonder how these two alternatives would compare in an airplane setting. My first opportunity to evaluate this came last weekend when I flew out to the UK to visit my dear old mom (in fact, I'm penning this column whilst sitting at the table in my little bro's dining room).   Sad to relate, the results were a bit of a mixed bag as it were. The X54 Earmuffs do an outstanding job of removing the higher frequencies from the background noise, including neighbors talking to you, babies wailing, and the pilot announcing that the engines have failed and it's time to put your head between your legs and prepare to shrug off this mortal coil. On the other hand, these earmuffs don't manage to remove all of the low-frequency noise from the engines.   By comparison, the noise-cancelling headphones perform magnificently with regard to removing the low-frequency engine noise, but they do tend to leave some of the higher frequency noise.   I kept on swapping back and forth trying to make up my mind which solution was best. I eventually stopped when I realized I was getting thoughtful looks from some kids who were seated across the aisle from me (it may be they were lost in admiration for my Hawaiian shirt of the day, but I sort of doubt it).   In the end I opted for my noise-cancelling headphones because they are lighter and more stylish and -- all other things being equal -- I have to justify buying them to myself. Having said this, if someone were to ask me to advise them whether to spend $400 on noise cancelling headphones versus $25 on a pair of earmuffs, I think I have to say that the earmuffs would win the day.   Of course, technology continues to move on. I purchased my noise-cancelling headphones three years ago. Consider how far things like tablets and smartphones have progressed since then. It may be that today's noise-cancelling headphones can totally out-perform the ones I own. Do you have any tidbits of trivia, nuggets of knowledge, or pearls of wisdom to share on this topic?     Max Maxfield EE Times

Hmmm, it appears that the title of this column has the potential to be a tad confusing. I'm not talking about music suppressors that are really annoying -- I'm more concerned with finding something that can help me suppress really annoying music. Let me elucidate (don't try this at home. I'm a professional)...   Before we start, it might be worth taking a moment to set the scene. My wife (Gina the Gorgeous) has a humongous family on her mother's side. (She can actually trace the family back to Nova Scotia and then to Europe before the Pilgrim Fathers landed, but that's a tale for another day.) Gina's mother was one of seven siblings. Her mother's mother was one of ten. Most of the family lives in Louisiana.   About ten years ago we had a big get-together featuring just two branches of the family (branches at Gina's grandmother's level). It took the camping grounds at a really large state park to accommodate all of us. Did I ever mention that I'm really bad at remembering names and faces? But we digress …   Last week, Gina, our son Joseph, and I went down to Louisiana to celebrate Gina's birthday. During the day, Gina and Joseph visited with her mother and aunts and uncles and cousins while I worked out of our hotel room, then I met up with them all in the evenings. The reason for my mentioning this here will become apparent in a moment.   Gina loves music. She plays it all the time. She's also amazingly knowledgeable. If a tune comes on the radio and I say, "Who's that?" (or, possibly, "What's that rubbish?"), she will immediately respond with the group, album, track, and the year in which it appeared on the scene, and she's invariably right on all counts. (I can do the same sort of thing, but in my case I'm just making things up.)   The problem (for me) is that Gina likes her music really loud. She’s also keen on listening to Christian rock when she’s driving. I think both of these things are wonderful … just so long as I'm not in the car with her. The downside for me comes when we happen to be taking a long drive together -- say an 8.5 hour drive down to Louisiana (just to pick a hypothetical example out of thin air, you understand).   Now, I'm the proud owner of some amazing MDR-NC500D digital noise-cancelling headphones from Sony. I picked these up on a trip three years ago when I went to give a talk to a bunch of engineers at Microsoft in Seattle, Washington (see I've fallen in love! ).       These little beauties bring tears of joy to my eyes whenever I'm flying somewhere on a plane. The difference when you activate the noise cancellation is truly amazing. Since I had my backpack with me on our trip to Louisiana, I surreptitiously donned these headphones. Do you know, I hadn’t realized just how much ground noise there is when you are travelling in a car -- even a really nice car like Gina's? When I turned on the noise cancellation, the rumble from the ground almost completely disappeared. Unfortunately, the noise cancellation doesn’t work on things like music, so the end result was to make the songs Gina was playing sound clearer and -- paradoxically -- louder.   It's amazing how we humans can forget what pain feels like. Once we'd arrived in Louisiana, I was swept away by the fun and frivolity, and the horror that is Christian rock became naught but a distant memory … until the time came for our 8.5 hour return trip. All I can say is that there was much metaphorical gnashing of teeth and rending of garb on the way home. Thus it was that I decided something had to be done to save me from similar anguish in the future. Upon our return, I started to Google furiously. Initially, I honed in on a pair of 3M Peltor H10A Optime 105 Earmuffs from Amazon. These weigh in at 12.3 ounces, have an NRR (noise reduction rating) of 30dB, and are an absolute bargain at only $21.61.     However, I then ran across a pair of 3M Peltor X5A Earmuffs as illustrated below. On the one hand, these are a little more boring to look at. They are also a tad more expensive at $25.92. But their main claim to fame is that they boast an NRR of 31dB.     Of course, you might be tempted to ask, "What's the big deal -- what's 1dB between friends?" All I can say in response is that -- when it comes to my listening to Christian rock -- every extra dB of noise reduction is worth its weight in gold.   These little scamps arrived at my office yesterday. I immediately put them on and took them for a stroll around the building. It was wonderful -- I couldn’t hear a thing. While I was perambulating along, my chum Paul saw me scampering past his office, and he came out to see what all the fuss was about.   When I explained about my noise-reducing earmuffs, Paul begged to try them on. He explained that he has a large ride-on mower. (He and his wife own a pretty big property out in the county.) His usual modus operandi while mowing the yard is to crank his Bluetooth earbuds up to full volume, which obviously does not bode well for his long-term hearing.     As you can see in the image above, Paul actually has his earbuds on under my earmuffs. He says that he can now run these at a low volume and that the quality of the sound is incredible. The last I saw of Paul, he was bounding into his office crying, "I've got to get me some of these!"   But wait, there's more … I took my earmuffs home. Yesterday evening, while Gina was watching some dross called Dance Moms on TV, I whipped out my trusty little beauties and slapped them on my head and … it was like being transported to another world. (The strange writhing that ensued in my seat can be attributed to my performing my happy dance while remaining in a reclined position.)   In conclusion, I'm delighted to report that all is now "peachy" in the Land of Max (where the colors are brighter, the butterflies are bigger, the birds sing sweeter, and the beer is plentiful and cold). How about you -- do you think you might be tempted to invest in a pair of these little rascals?  

For several years, I have been using headphones exclusively for listening to almost all audio sources—such as music, videos, podcasts etc.—and have consequently always been very interested in obtaining the best quality sound from them possible, especially for music playback. This often meant subjectively trying out different headphone brands and models, trying to find ones with the "flavour" that I preferred. As someone who prefers accuracy in reproduction, however, I always wished for a more objective approach for achieving it with headphones. Unlike with a loudspeaker/room system, the sound produced in the headphone/ear interface is not only dependent on one's individual auditory canals, it doesn't lend itself to easy measurement and correction. So I was quite intrigued when, some time back, I ran across Siegfried Linkwitz's webpage on " Reference earphones ," where he found that the perceived frequency response of headphones (relative loudness changes determined by sweeping over the frequency range with an audio signal generator) typically exhibited significant—but narrow—peaks, which could vary from person to person. Linkwitz's suggested solution was a simple passive LCR notch filter circuit—to be placed between a headphone amplifier output and the headphones—designed to achieve a uniform perceived amplitude response for a particular listener and pair of headphones/earphones. This plot shows the voltage across the transducers (in this case Etymotic ER-4S earphones) with and without the notch filter equalisation circuit that Siegfried Linkwitz found was needed in order to achieve a uniform perceived amplitude response to sine waves when tuned for his ears. (Linkwitz Lab) I still have plans to build and try this circuit, but since most of my headphone listening is done either on my PC (using a USB audio DAC) or an iDevice, my immediate thought was how I might implement this through digital/software means. The testing part is easy—there are any number of software programs and apps available capable of generating the sine wave tones needed for determining the perceived frequency peaks for a given headphone/ear combination. When I tested a couple of different high-quality headphones, I heard what appeared to be some significant response peaks, very similar to what Linkwitz described. It was much trickier coming up with a playback equalisation solution that had the required parametric equalisation capabilities—i.e., the precise control over amplitude, centre frequency and bandwidth needed to implement notch filters. Fortunately, an extended discussion on Head-Fi (" How to equalise your headphones: A Tutorial ") offered some suggestions. For music playback on my PC, I ultimately ended up using the Electri-Q equaliser as a plug-in with the foobar2000 audio player to notch out the perceived peaks. The resulting difference between the equalised and unequalised sound was also as Linkwitz described—"switching the equalisation out of the signal path reveals a very exaggerated high-frequency emphasis of certain sounds and an overall colouration." The real trick, however, is achieving this on an iDevice. Typically iOS apps all operate separately, each in their own independent operating space. So, unfortunately, this means it's not possible to process the output of your favourite music playback app through a separate equaliser app. The only solution has been to find an appropriate equaliser app and then use it as your music player (a secondary function that any such processing apps have needed in order to be useful). Several parametric equaliser apps are available, including EQu, Equalizer, and Accudio. These may not represent ideal solutions, but will allow full control over the equalisation of music played back on the device—as long as the music is stored on the device. Unfortunately, my favourite—and only—music "playback" app is iPeng. I don't have any music files stored on my iDevices. I use the "Playback" feature in iPeng to wirelessly stream audio from a Vortexbox media server (where my music library is stored) to my iDevice. So I am still left without a software-based headphone equalisation solution on my iPad and iPod. However, there have been some interesting developments lately in another area of the iDevice audio space that could offer a solution. I'll be discussing those in an upcoming post. Rich Pell EE Times  

I got myself a new pair of noise-canceling headphones that have me tap-dancing down airplane isles with bliss... A few days ago, I flew out to Seattle, Washington, to give a talk to a bunch of engineers at Microsoft. While I was there, I texted my wife ("Gina The Gorgeous") to tell her I'd been told that there were 70,000 Microsoft employees scattered over the various Redmond campuses. She responded with a text saying "OMG!" which I thought was jolly enthusiastic of her. However, it turned out that she had misunderstood what I was saying and she thought I was giving my presentation to all 70,000 of the little rascals (I would have required a stadium the size of the Super Bowl venue :-) During my outbound journey I decided to watch a free pilot episode of a new TV program called Franklin Bash that I'd downloaded to my iPad. The quality of the video itself was wonderful. Sad to relate, however, I had only my old iPod earbuds in my backpack, which made it somewhat difficult to hear the audio track over the plane's engine noise. The thing was that I had also downloaded two science fiction films to my iPad, and I was looking forward to watching these little scamps on my return journey. Thus, I determined to treat myself to some new noise-canceling headphones. As an aside... The films in question were Monsters and Outlander . The first, Monsters , is about extraterrestrial lifeforms that were brought back to earth in the form of seeds / spores by a malfunctioning NASA space probe. We join the story six years after the probe crashed, by which time the entire northern part of Mexico is a quarantine zone. The story follows two Americans who have been stranded in Mexico below the quarantine zone and who have decided to fight their way overland through the zone back to America. If you look at the reviews on Amazon you will see an average of only three out of five stars from 184 reviewers. This doesn't seem so good, and normally I wouldn't have gone further, but the positive reviews I read were very positive, so I decided to take the plunge and I'm glad I did. This film isn't for everyone. It's not a fast "shoot-them-up" sort of film and the alien "monsters" aren't "in your face" all of the time. This is a more thoughtful, slow-paced film with great cinematography and music. It's hard to describe. I liked it. I probably won't watch it again, but I'm glad I did watch it this time. The second film, Outlander , is a combination of the classic tale of Beowulf with a science fiction twist. It involves spaceships and alien monsters overlayed into ~750 AD Norway. This may sound like a disaster waiting to happen, but in fact the end result is really rather good – great acting, fantastic special effects, and enthralling action that left me gripping my seat and thinking "There's no way you would get me to go in there..." But we digress... I already have a pair of Bose noise-canceling headphones that I purchased two or three years ago (I'd left these at home because I wasn't thinking). To be fair, the Bose do cancel out quite a lot of aircraft noise, but not as much as I'd originally hoped for. Also, they sit on top of my ears, so they start to become uncomfortable after a couple of hours. With the leaps and bounds in signal processing algorithms and the increases in processor performance we've seen over the last few years, I decided that noise-cancellation technology had probably advanced a lot since I purchased my Bose. Also I decided that I should treat myself (who deserves it more than I?) Thus it was that, on the return journey, I arrived at the airport early enough to give myself time to fight my way through security and check out the headphone offerings. I went to a little electronics store in the main terminal and – without much hope of receiving an intelligent answer (if the truth be told) – asked the young lad behind the counter "What are the best noise-canceling headphones?" He took me by surprise by being incredibly knowledgeable. He first said that it depended on exactly what I wanted. If I was looking for the best noise cancellation he would recommend the Sony MDR-NC500D ; but if I was looking for the best possible audio quality coupled with a little less on the noise-cancellation front, then he would recommend something else (I can't remember what the alternative was). I opted for the Sony MDR-NC500D headphones and I have fallen in love with them. Quite apart from anything else they are easy to use. The main control is an On/Off button (I can handle that). There's also a Monitor push button that disables the noise cancellation as long as you hold it down. I'm not sure exactly what this button's reason for being is, but I found myself pressing it every 15 minutes or so just to I could contrast the huge amount of noise with the headphones disabled with how fantastically quiet things were when the noise-cancellation was active.   The Monitor, On/Off, and AI buttons are visible on the right-hand earpiece The other control is an AI (Artificial Intelligence) button. The guy in the shop explained that different planes have different noise profiles. A Boeing 747, for example, will have more base frequencies than a smaller jet. When you push and release the AI button, the headphones sample the sound profile for a few seconds and then adjust their noise canceling algorithms accordingly. Also, these little rascals are large enough that they fit completely over my ears, so they remain comfortable even after hours of use. In one of the films (see above) there was a part where we were in a forest and the only sounds were crickets and birds and suchlike ... and everything sounded as clear as one could hope. You really have to try these little beauties to fully appreciate just how amazing they are (but you will have to purchase your own – the only way anyone will get mine is after a fight when they pry them from my lifeless hands). How much were these headphones? I'm embarrassed to say. I'm sure that they cost more in the airport and that you can get them cheaper on the web, but I wanted them then and there so that was that (if you see what I mean). Suffice it to say that I have never in my life paid so much for a pair of headphones, but I think they are worth it because I actually travel quite a lot in the scheme of things. In a couple of weeks, for example, I will be going to England to visit my dear old mom – and my new headphones will make my journey much more pleasant. When you divide the cost of these headphones by the number of hours I will use them over the course of the next 10 years ... they are still #$%^ expensive when I come to think about it ... but I just don't care because I'm worth it (grin).