4 ms·

> The headphone jack is a “just works” kind of technology: there’s nothing complicated about it [..] While the connector itself is indeed simple, a DAC is also

> The headphone jack is a “just works” kind of technology: there’s nothing complicated about it [..] While the connector itself is indeed simple, a DAC is also needed inside, and one needs a decent DAC/amp on the phone to get a decent signal. In a cheaper smartphone, you are probably better off with bluetooth/aptx. Moreover, jack cables "just work" until they start making weird stuff depended on how they get bent or stretched or the connectors touch. I experience a surge of anxiety even writing this right now.

ghusto 2y ago
> In a cheaper smartphone, you are probably better off with bluetooth/aptx Even a cheap phone’s DAC is going to sound better than any BT codecs.
- Kirby64 2y ago
  Not true, modern BT codecs can be essentially transparent, and cheap 3.5mm jacks can have all sorts of issues. Bad noise performance, bad interchannel isolation, pop click issues, etc. don’t underestimate how badly you can design a 3.5mm jack especially if the phone only costs like $50 total.
  - brnt 2y ago
    Despite what audiophiles believe, DACs are a relatively solved problem and quality does not correlate with price.
    - Kirby64 2y ago
      As a non audiophile who designs this stuff for a living, you’re correct it’s not difficult or even particularly expensive. But it’s also surprisingly common to do it poorly.
- noisem4ker 2y ago
  The only truly, audibly lousy Bluetooth codec is low-bitrate SBC. Anything better than that is going to be transparent to most ears. The awfulness of cheap/low-power DACs, on the other hand, knows no limit.
  - brnt 2y ago
    There is going to be a DAC somewhere, and somehow putting it in the headphones doesn't speak for quality. Power budget, if nothing else.
    - Kirby64 2y ago
      It’s much easier to make a headphone output that is tailored to a very specific driver than it is to make a generic headphone driver that can drive any conceivable headphone plugged in.
noisem4ker 2y ago
You need the DAC/amp for the built-in speaker(s) anyway.
yjftsjthsd-h 2y ago
> In a cheaper smartphone, you are probably better off with bluetooth/aptx. If we assume a cheap phone has a garbage DAC, we should assume a cheap phone has garbage Bluetooth. That might mean better audio quality when it works, but also connectivity problems and excessive power consumption.
atoav 2y ago
If we're talking phones you need an ADC anyways to digitize the microphone signal (unless you're using a dedicated microphone IC). There are many ICs which give you ADC and DAC in one package, the only thing you potentially need is the output circuitry to drive the headphones. On top of that you need a DAC for your speakers anyway and since phones don't use speaker and headphone outputs for different things you could just route the amplified signal from the DAC through the switch contacts of the headphone jack which disconnects the speakers if a plug is inserted.
- Kirby64 2y ago
  Nobody uses the same DAC for headphone output as they do for speakers. There’s dedicated devices for each of these in every system, as it’s just more efficient. Also, most devices allow simultaneous output on headphone and speakers (think, notifications). These devices are all monolithic for the particular function, and generally for good reason.
  - atoav 2y ago
    Yeah? Like that one which has an ADC, hwadphone and speaker driver? https://www.ti.com/lit/ds/symlink/tlv320aic28.pdf?ts=1725285384387 https://www.ti.com/lit/ds/symlink/tlv320aic28.pdf?ts=1725285... We are talkinf about whether additional electronics were the death of the headphone jack – I argue no. If anything it is the jack itself that they wanted to get rid of. Also likely they additionally wanted to sell more earbuds (maybe that was even the primary driver). If anybody could tell us they probably are on HN.
    - Kirby64 2y ago
      Nobody is using a part like that for any speaker output in a cell phone, let alone a laptop. Modern speaker drivers are closer to 8-12W (even in cell phones) so the wimpy 400mW of that device is worthless. It’s also in a package completely unsuitable for a cell phone, and doesn’t have any of the integrated jack detection that is needed in modern 3.5mm audio codecs.

ghusto 2y ago

> In a cheaper smartphone, you are probably better off with bluetooth/aptx Even a cheap phone’s DAC is going to sound better than any BT codecs.

Kirby64 2y ago
Not true, modern BT codecs can be essentially transparent, and cheap 3.5mm jacks can have all sorts of issues. Bad noise performance, bad interchannel isolation, pop click issues, etc. don’t underestimate how badly you can design a 3.5mm jack especially if the phone only costs like $50 total.
- brnt 2y ago
  Despite what audiophiles believe, DACs are a relatively solved problem and quality does not correlate with price.
  - Kirby64 2y ago
    As a non audiophile who designs this stuff for a living, you’re correct it’s not difficult or even particularly expensive. But it’s also surprisingly common to do it poorly.
noisem4ker 2y ago
The only truly, audibly lousy Bluetooth codec is low-bitrate SBC. Anything better than that is going to be transparent to most ears. The awfulness of cheap/low-power DACs, on the other hand, knows no limit.
- brnt 2y ago
  There is going to be a DAC somewhere, and somehow putting it in the headphones doesn't speak for quality. Power budget, if nothing else.
  - Kirby64 2y ago
    It’s much easier to make a headphone output that is tailored to a very specific driver than it is to make a generic headphone driver that can drive any conceivable headphone plugged in.

noisem4ker 2y ago

You need the DAC/amp for the built-in speaker(s) anyway.

yjftsjthsd-h 2y ago

> In a cheaper smartphone, you are probably better off with bluetooth/aptx. If we assume a cheap phone has a garbage DAC, we should assume a cheap phone has garbage Bluetooth. That might mean better audio quality when it works, but also connectivity problems and excessive power consumption.

atoav 2y ago

If we're talking phones you need an ADC anyways to digitize the microphone signal (unless you're using a dedicated microphone IC). There are many ICs which give you ADC and DAC in one package, the only thing you potentially need is the output circuitry to drive the headphones. On top of that you need a DAC for your speakers anyway and since phones don't use speaker and headphone outputs for different things you could just route the amplified signal from the DAC through the switch contacts of the headphone jack which disconnects the speakers if a plug is inserted.

Kirby64 2y ago
Nobody uses the same DAC for headphone output as they do for speakers. There’s dedicated devices for each of these in every system, as it’s just more efficient. Also, most devices allow simultaneous output on headphone and speakers (think, notifications). These devices are all monolithic for the particular function, and generally for good reason.
- atoav 2y ago
  Yeah? Like that one which has an ADC, hwadphone and speaker driver? https://www.ti.com/lit/ds/symlink/tlv320aic28.pdf?ts=1725285384387 https://www.ti.com/lit/ds/symlink/tlv320aic28.pdf?ts=1725285... We are talkinf about whether additional electronics were the death of the headphone jack – I argue no. If anything it is the jack itself that they wanted to get rid of. Also likely they additionally wanted to sell more earbuds (maybe that was even the primary driver). If anybody could tell us they probably are on HN.
  - Kirby64 2y ago
    Nobody is using a part like that for any speaker output in a cell phone, let alone a laptop. Modern speaker drivers are closer to 8-12W (even in cell phones) so the wimpy 400mW of that device is worthless. It’s also in a package completely unsuitable for a cell phone, and doesn’t have any of the integrated jack detection that is needed in modern 3.5mm audio codecs.