[HN Gopher] Homebrew Bluetooth Headphones
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       Homebrew Bluetooth Headphones
        
       Author : cunidev
       Score  : 187 points
       Date   : 2022-08-07 09:35 UTC (13 hours ago)
        
 (HTM) web link (homebrewheadphones.com)
 (TXT) w3m dump (homebrewheadphones.com)
        
       | bullen wrote:
       | I stocked up on Urbanears Plattan 2 during the last sale, they
       | are both bluetooth and cable headphones but you need to buy the
       | cable yourself, I bought kramer cables.
       | 
       | For $25 a pair they are easily the best headphones I have ever
       | had, my last pair was a Plattan 1 that lasted 8 years!!! (cable
       | broke once)
        
         | public_defender wrote:
         | Oh wow, the price has gone down a lot. These are great
         | headphones, but they're a relatively small on-ear profile. They
         | would have me as a customer forever if they had an over-ear
         | model. The best thing about them in my opinion is that they are
         | very easy to take apart and clean.
        
         | aaaaaaaaaaab wrote:
         | I used to have a Plattan myself in 2010, but had to sell it
         | because the pads felt painful when wearing them longer than 30
         | minutes... A lot of people posted reviews with the same issue.
         | 
         | Quite a shame, because I really like the design.
        
       | thatcat wrote:
       | Found a wired version
       | https://www.instructables.com/DIY-3D-Printed-Headphones/
        
       | dijonman2 wrote:
       | I really want long range bluetooth, from one side of my house to
       | the other. I like to walk around while on calls and range sucks.
       | 
       | I looked into bodypack solutions but it's receive or transmit,
       | can't find transceivers.
        
         | infofarmer wrote:
         | If you're looking into bodypack, why not just carry the phone
         | around? Spotty Wi-Fi / 4G coverage?
        
           | dijonman2 wrote:
           | This is for calls where dial in is not permitted.
        
             | mikestew wrote:
             | And to support what sibling said, I open the Teams app on
             | my phone, not dial in, join the meeting and go walk the dog
             | around the neighborhood. Unless you simply don't have a
             | smartphone (or an app for your meeting software), I can't
             | see how one would more simply solve your problem.
        
             | vladvasiliu wrote:
             | Are you not allowed to use Teams / Zoom / whatever on the
             | phone? I used to do this before I had wireless headphones.
        
         | vladvasiliu wrote:
         | If it's just for calls, look at DECT headphones. I have a Jabra
         | model, don't know if they still make them.
         | 
         | Coverage is great, I can walk around my parents' house, and
         | even out in the garden, without loss of signal. They live in a
         | hundred-year-old stone house.
         | 
         | Sound quality is great for calls. Music is ok-ish. They don't
         | have any kind of ANC.
         | 
         | Another drawback is the big-ass base that for some reason
         | requires a dedicated power cord.
        
           | rkagerer wrote:
           | For phone calls, Plantronics CS55 has worked great for me for
           | over a decade. (Range not be as long as you need though)
        
           | dijonman2 wrote:
           | Thanks for that, I am looking at POTS audio interfaces and
           | POTS simulators. Looks like with DACT I can do what I want
           | cheaper than using multiple body packs.
        
       | nyanpasu64 wrote:
       | How practical is homebrew open codec support, like building
       | Bluetooth headphones or receivers with software/hardware Opus
       | decoding support (as opposed to conflict-of-interest proprietary
       | codecs that the Bluetooth standards authors add to the standards,
       | then profit from license fees)?
        
         | rollcat wrote:
         | Is Opus optimized for latency, battery usage, and widely
         | supported in common hardware? I don't mind paying a royalty fee
         | if it affords me a better experience when actually using the
         | product.
        
           | themerone wrote:
           | Opus is low latency and higher quality than the other music
           | formats. It was designed to be suitable as a low delay voip
           | codec.
           | 
           | I've never seen comparisons to the proprietary Bluetooth
           | codecs, but those are always implemented in hardware so it is
           | impossible to do.
           | 
           | I don't know about battery usage, but Opus is simple enough
           | to be implemented on micro controllers, so it should't be too
           | bad.
        
           | nyanpasu64 wrote:
           | Opus is one of the lowest-latency frequency-domain codecs out
           | there (not including ADPCM-style codecs), as well as being
           | the best-sounding voice and music codec at a given bitrate,
           | beating MP3 and AAC (excluding ultra-low-bitrate voice, and
           | recent neural codecs). In listening tests, LC3 is only better
           | than Opus when Opus is deliberately misconfigured to compress
           | audio badly.
           | 
           | Looking around for battery usage,
           | https://news.ycombinator.com/item?id=21982964 claims LC3 is
           | no simpler to decode in specialized low-powered hardware than
           | Opus, while https://hydrogenaud.io/index.php?topic=118692.msg
           | 979046#msg9... claims LC3 is "basically Opus with a few
           | marginal gadgets thrown in". In that case, I think the only
           | reason Opus couldn't be as widely supported as LC3 is that
           | there isn't money to be extracted from the system.
        
             | rollcat wrote:
             | Thanks for the explanation. So it's a different situation
             | from e.g. hardware H264 decoders, where the extra silicon
             | makes a dramatic difference.
             | 
             | Then the main concern remains interoperability. I'd still
             | pay a bit more to make sure my friend's random device has a
             | better chance of working at all. Bluetooth is already a
             | tire fire so I wouldn't like to add another layer of
             | interop issues.
        
               | nyanpasu64 wrote:
               | Hardware Opus decoders are completely unnecessary for
               | desktops, and probably so for laptops or even phones I
               | think. It's possible it substantially improves battery
               | life in small-battery headphones and such, or it's
               | physically impossible for headphone Bluetooth chips to
               | support CPU decoding. But I doubt Opus is any harder to
               | implement in hardware (or DSP firmware) than LC3 (which I
               | don't know if it's easy to implement, but I assume
               | they're trying to get hardware to support it).
        
       | DarthNebo wrote:
       | I just wanted to be able to use 18650 cells in my headphones &
       | never worry about battery life.
        
         | dghlsakjg wrote:
         | At a quick glance the hardware for this is compatible with
         | Lithium Ion chemistry so go for it. Just need to make some
         | minor mods to put a battery holder on.
         | 
         | More specifically, just about any headphone with a LiPo (flat
         | square) battery could be modified to accept an 18650. The
         | charging voltages are the same, so you would just have to snip
         | the old battery out and wire in an 18650.
        
         | xchaotic wrote:
         | These are overkill and way too heavy for headphones
        
       | melkael wrote:
       | The instructions recommend to print with ABS. Any reason for not
       | going for PETG or PLA ?
        
         | eurasiantiger wrote:
         | Higher glass transition temp so can be left in the car, and
         | less prone to break when dropped?
        
         | Saris wrote:
         | PLA and PETG start to soften at lower temps, 60C and 80C
         | respectively. But ABS is up at 105C, so it won't have any
         | chance of deforming in a hot car or something.
         | 
         | I still think 80C on PETG should be high enough, and it's a
         | much nicer material to print.
        
       | intsunny wrote:
       | The whole bluetooth headhones situation is a little ironic.
       | 
       | Us Linux types remember how long it took until the MP3 patents
       | expired for us to stop having to add non-free repos everywhere
       | and being treated as the ugly cousin because we couldn't support
       | such a universal codec out of the box.
       | 
       | Fast forward today, and we're back at square one because everyone
       | and their mother wants some new codec to make bluetooth audio
       | quality suck not so bad. (Bluetooth couldn't do better than SBC
       | out of the box? really?)
       | 
       | The only difference between yesterday and today is that, we Linux
       | folks are much better at quickly enabling support for proprietary
       | codecs out of the box.
        
       | tehwebguy wrote:
       | This rules! I have one of this bluetooth chip but mine didn't
       | come with the breakout pre-soldered & I'm struggling to solder
       | them myself, thinking I should try paste + heat gun.
       | 
       | I believe you can also can change the name that the BT module
       | broadcasts if you have an FTDI to USB cable (or something with
       | UART pins like an Arduino). (You can also just change the
       | "display name" on your iOS device bluetooth settings but it is
       | just the name your device shows. I'm guessing this is doable on
       | Android and everything else too.)
        
       | userbinator wrote:
       | I believe the CSR chipsets have some programming tools available
       | as well, so you can change things like the voice prompts to your
       | liking (many of the cheap modules seem to come with the infamous
       | "the Bluetooth device is ready to pair" meme sound) and adjust
       | the device name.
        
       | pxx wrote:
       | > They sound awesome - on par with pairs that cost around $200
       | 
       | I don't know. The problem is that $20 pairs often sound on par
       | with ones that cost around $200. But the ones that cost around
       | $200 have much better ANC than the $20 ones. You can definitely
       | tell on an airplane. And these don't have noise cancelling at
       | all.
        
         | willcipriano wrote:
         | Bluetooth audio isn't fantastic in my experience. I prefer
         | wired if I'm looking for sound quality.
         | 
         | Still you'll enjoy something you made yourself more than the
         | $200 version you just bought.
        
           | codethief wrote:
           | > Bluetooth audio isn't fantastic in my experience.
           | 
           | I had been thinking the same but then I still gave it a shot
           | and bought some new headphones with Bluetooth (and aptX
           | support), in my case the Sennheiser Momentum True Wireless 2
           | (in-ear), and the Sennheiser Momentum 3 (over-ear). Turns out
           | they can easily compete with (or are even better than) the
           | cable-bound ~$250 in-ears I used to have.
        
             | bosie wrote:
             | Does the momentum 3 sound better when you use the cable for
             | it?
        
               | blangk wrote:
               | I would say the difference is not easily noticeable but I
               | haven't done exhaustive testing as I've only really used
               | the cable when FPS gaming on them
        
               | codethief wrote:
               | I haven't noticed a difference to be honest.
        
             | erdewit wrote:
             | When playing FLAC music over aptX HD, the next step for
             | improvement is to avoid any resampling. The music is
             | generally at 44.1 kHz and the default for Android is 48
             | kHz. It requires root to change the audio config file to
             | 44100, and it's also necessary to change the bluetooth
             | settings (in the developer options).
             | 
             | Something similar goes for Linux.
             | 
             | The resampling shouldn't matter much in theory, but in
             | practice it's pretty noticeable. It seems to be optimized
             | for CPU usage instead of audio quality.
        
               | userbinator wrote:
               | _It seems to be optimized for CPU usage instead of audio
               | quality._
               | 
               | Presumably on an Android phone, it makes sense to lower
               | CPU usage (and thus prolong battery life) rather than go
               | for the best audio quality.
        
             | 2muchcoffeeman wrote:
             | You can get OEM bluetooth in-ear buds straight from China
             | quite easily these days. They are cheap and punch well
             | above their weight. My wired ear buds are subjectively
             | better sounding to me. My wired ear buds connected to a BT
             | receiver also sound better. But the OEMs cost on the order
             | of 50AUD/35USD...
        
           | [deleted]
        
           | marcinzm wrote:
           | >Still you'll enjoy something you made yourself more than the
           | $200 version you just bought.
           | 
           | That's not the case for me. I enjoy the process of making
           | something but in terms of day to day usage I enjoy the better
           | version more.
        
             | iasay wrote:
             | Similar. I enjoy the effort someone else has put in to work
             | all the bugs out.
        
           | jefftk wrote:
           | If you don't care about latency, like listening to music or
           | watching a movie, Bluetooth audio can be as good as wired.
           | The maximum bandwidth for Bluetooth audio is 576kbps (aptX
           | HD) which is way above the point at which you can tell the
           | difference.
           | 
           | On the other hand, if latency is important, like on a call,
           | then you can get kind of reasonable latency if you almost
           | give up on quality (34ms from aptX Low Latency) But you're
           | much better off sticking with wired (low single digit
           | milliseconds) since latency matters so much for good
           | conversation.
        
             | ajolly wrote:
             | It's frustrating to me that even high-end apple and both
             | noise canceling headsets don't have low latency support
        
             | netr0ute wrote:
             | > The maximum bandwidth for Bluetooth audio is 576kbps
             | (aptX HD)
             | 
             | 100% pure unadulterated USDA-certified Prime grass-fed
             | gluten-free all natural organic free-range BS, as the LDAC
             | codec for BT comes in 330, 660, and 990kbps flavors and has
             | even lower THD than aptX HD and an even wider frequency
             | response (essentially to 20KHz). The catch is, only a few
             | really recent and expensive chips have support for it, so
             | almost nobody has heard (of) it, literally.
        
               | MayeulC wrote:
               | SBC sounds really good too if you negociate a higher
               | bitrate than the "high quality" profile. Sometimes called
               | SBC- XQ, and most receivers support it.
        
               | AshamedCaptain wrote:
               | SBC is practically transparent at these bitrates anyway,
               | or at least on the level of other 320kbps codecs. The
               | differences are so inaudible that even listening tests
               | have a hard time telling the different codecs apart.
               | http://soundexpert.org/encoders-320-kbps
               | https://habr.com/en/post/456182/
               | 
               | These talks about replacement, higher-bitrate codecs
               | always have always been very dubious.
        
               | netr0ute wrote:
               | The trick is, though, even though SBC is only marginally
               | worse than lossless, because it's the lowest common
               | denominator codec, you tend to see it with worse DACs
               | that also have to do with the end audio quality. When you
               | use codecs like LDAC, you tend to also see them with high
               | quality components that would make it seem like it's LDAC
               | that's doing the work, but it's in reality just a bonus.
        
               | jefftk wrote:
               | I'm glad there's an even higher bandwidth option I didn't
               | know about! But at this point no one is hearing the
               | difference, and this isn't a reason to go with wired over
               | Bluetooth, as long as you can get hardware that supports
               | a good enough codec.
        
       | harha wrote:
       | Small side note on Bluetooth:
       | 
       | I regularly use four devices (phone, tablet, laptop, desktop) and
       | I have two pairs of headphones (in ear and over ear).
       | 
       | Since it's 2022 and we have so much amazing technology all around
       | us, these are the two things I'm missing: I'd like to be able to
       | use any combination of these without pairing again and I'd also
       | really like to stay connected while I'm listening to something or
       | having a conversation.
       | 
       | Is this really too much to ask for? Now the funny thing is that
       | it doesn't matter if I spend $20 or $200. I've heard AirPods may
       | be better as long as you stay in the apple ecosystem, but that's
       | one constraint too much.
        
         | [deleted]
        
         | hombre_fatal wrote:
         | It would be more interesting if we started threads about TFA
         | instead of rehashing the same generic complaints about X just
         | because X appears in the title.
        
           | harha wrote:
           | Ok let me rephrase that: can anyone explain why this common
           | scenario doesn't work and if there's any way to solve this?
           | Would a homebrew device running my own software help?
        
             | scarface74 wrote:
             | I can't imagine dealing with the shit show of BT outside of
             | the Apple ecosystem in 2022.
             | 
             | You're not going to like the obvious answer - get into the
             | Apple ecosystem and buy Apple headphones.
             | 
             | They seamlessly switch between my iPhone, iPad and Mac. If
             | I am watching something on my iPad and my iPhone rings,
             | they automatically switch. If I start watching a video on
             | my iPad and then start playing a video on my iPhone, they
             | automatically switch.
             | 
             | Not to mention if I'm using my AirPods with my AppleTV at
             | night and my wife starts talking to me, I just take one
             | side out and the TV pauses.
             | 
             | Of course they work in just the opposite manner. If I put
             | them in, audio switches to them.
             | 
             | I'm not sure if auto switching from my watch. But since I
             | can take phone calls on it anyway. It doesn't matter as
             | much.
             | 
             | Also if I pair to any device connected to my Apple ID, all
             | of my other devices automatically show them as an option -
             | iPad, iPhone, AppleTV, Watch, Mac.
        
             | mbreese wrote:
             | To echo the sibling comment -- Apple has largely solved
             | this problem, within the Apple ecosystem. If you want to
             | avoid Apple, then you're up to the will of N vendors want
             | to try to solve the problem their own way, so...
             | 
             | For Apple, the key feature is iCloud. Your headphone
             | bluetooth information is stored in iCloud, so any
             | headphones that have been paired with one device, are
             | paired with all other devices. This is the secret sauce
             | that make the system work. But even here, there can be
             | issues. My Airpods connect to all of our Apple TVs, but my
             | wife's don't. My iCloud account is the primary one, but I
             | haven't figured out how to get my wife's headphones to
             | transfer over as easily. So, even here -- when things work,
             | they work great. When they don't -- you're stuck.
             | 
             | As far as using custom firmware, I'm not sure how much that
             | would help you. The CSR8645 module from the article has its
             | own firmware already installed and running. It looks like
             | customizing would require some kind of license from
             | Qualcomm. But, even then -- the secret sauce for migrating
             | headphones from device to device isn't in the headphones.
             | It's in the devices. So, that's where you'd need to add
             | some custom code.
        
               | happyopossum wrote:
               | > My Airpods connect to all of our Apple TVs, but my
               | wife's don't
               | 
               | The key is to add your wife as an additional user on the
               | AppleTV. The ability has been there since at least tvOS
               | 13.x
               | 
               | https://support.apple.com/guide/tv/multiple-users-
               | atvb59ec8e...
        
       | terramex wrote:
       | I have converted my old Beyer Dynamic DT 770 to Bluetooth [1] and
       | used them daily for past 6 months and I recommend this BT module
       | over what is listed on that website:
       | https://www.gotronik.pl/odbiornik-bluetooth-50-audio-aptxll-...
       | 
       | It has 5V stepdown converter and Li-Po charger as well as
       | amplifier integrated on board. Cheap USB-C Li-Po chargers lack
       | neccessary 5.1kOhm pull-downs and therefore work only with
       | USB-A->USB-C cables. Soldering them onto charger PCB is
       | borderline impossible, while adding them to most USB-C sockets is
       | fairly easy (usually there are free pads to solder 5.1k SMD
       | resistor). You then connect 5V and GND from USB-C socket to BT
       | module and it handles charging the battery that is connected to
       | separate pads.
       | 
       | I don't really understand why article recommends board without
       | amplifier, I tried using CSR8675 board without one and it was
       | waaay too quiet.
       | 
       | With 500mAh battery salvaged from old BT speaker I get over 20h
       | of loud playback, which is fine for me.
       | 
       | [1]
       | https://www.reddit.com/r/headphones/comments/r32ru2/yet_anot...
        
         | thatcat wrote:
         | Thinking of doing a similar mod to my shp9500. Have you tried
         | pairing this with an android phone yet? I'm also curious how it
         | sounds on aptx instead of aac.
        
         | leobg wrote:
         | I like that the Bluetooth part on the board is blue.
        
         | userbinator wrote:
         | _I don 't understand why article recommends board without
         | amplifier, I tried using CSR8675 board without one and it was
         | waaay too quiet._
         | 
         | It depends on the drivers; if they're low impedance, the result
         | may be deafeningly loud. Yours seem to be available in 32, 80,
         | and 250 ohms, the ones in the article are 32.
        
       | TaylorAlexander wrote:
       | These look nice! I have also been making my own headphones. I
       | recently posted a twitter thread with build instructions if
       | anyone wants to make them. [1]
       | 
       | Notable difference is that mine are simpler to build, though less
       | integrated. I use an off the shelf bluetooth to 3.5mm adapter
       | rather than one of those integrated boards (I did recently buy an
       | integrated board to test out). The off the shelf bluetooth
       | adapter just plugs in to the short 3.5mm cable I build in to the
       | headphones, which has the advantage that you can make them wired
       | headphones with a simple extension, which sometimes has its use.
       | Anyway take a look!
       | 
       | [1] https://twitter.com/TLAlexander/status/1550903550930067456
        
         | lostgame wrote:
         | I very much appreciate that your design incorporates the
         | ability to use them wired as well.
         | 
         | While I'm out/in transit, of course there's nothing
         | particularly terrible about Bluetooth.
         | 
         | When I'm at home, however - I produce music a _lot_ more than I
         | consume it.
         | 
         | I also mainly consume music at home on my record players
         | anyway, which obviously I don't use Bluetooth for.
         | 
         | As any audio producer will tell you; the latency introduced be
         | even the newest Bluetooth standards makes producing music in a
         | DAW a frustrating experience at best.
         | 
         | I love the 'best of both worlds' headphones with optional
         | latency-free wired support. I can take them on the go and use
         | Bluetooth on the bus, I can connect a wire at home; and produce
         | in bliss.
         | 
         | I would _absolutely_ love to create my own headphones from the
         | ground up sometime, choosing my drivers and cushioning
         | carefully, and ideally modelling /3D printing my custom design,
         | based on taking measurements of the shape of my head and size
         | of my ears. (I prefer over the head headphones as even the most
         | comfortable buds tend to hurt my ears after a short while.)
         | 
         | Sounds like a fun summer project sometime. :)
        
       | skeyo wrote:
       | The homebrewer in me was like "what do headphones have to do with
       | brewing"
        
         | zdw wrote:
         | Or with installing open source software on a Mac.
        
         | quercusa wrote:
         | Or Hebrew...
        
       | rob_c wrote:
       | Very cool, would be curious to know battery life Vs audio quality
       | but very impressive non the less
        
         | happyopossum wrote:
         | Battery life is listed at 5 hours, which to be frank, is
         | horrible.
         | 
         | 25-40 hours is pretty common with big over-ear headphones these
         | days, even ones with ANC...
        
           | rob_c wrote:
           | > 25-40 hours is pretty common with big over-ear headphones
           | these days...
           | 
           | well yes... But frankly given low power btle with audio chips
           | exist it's related more to chip/software than say the battery
           | type...
        
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       (page generated 2022-08-07 23:01 UTC)