• Speaker stand upgrade

    lion mclionhead • 03/07/2026 at 02:29 • 0 comments

    After a lot of drawing, came up with some really flimsy PLA stands which allowed them to pan but not tilt.  They were low enough to not have to tilt.  The trick is attachment to the desk is still based on tape.  The L shape has to be thin enough for tape to get around but printing such a shape requires printing walls.  Walls have to be 2mm thick.  Some more optimization could be done to make walls without tape 2mm & walls with tape 1mm.

    Definitely better than the arduino speakers & the original vivitar enclosure.  Still nowhere close to bookshelf size speakers.  The next step is EQ.

  • Bluetooth upgrade

    lion mclionhead • 03/04/2026 at 18:25 • 0 comments

    The line noise & power saving cutoff gradually got more problematic.  Noted power saving was still happening in certain conditions, despite adding noise to the sound.  It was not reproducible.


    Also noted with bluetooth audio, the start of playback has a lot of dropouts as the frequency hopping takes time to adapt.  Then it stabilizes.  Bluetooth is surprisingly robust for something that was invented 30 years ago & runs on the crowded 2.4Ghz band.  The adaptive frequency hopping didn't exist until 2003.  Bluetooth before 2015 was a pain in the ass, requiring extensive button gymnastics & a password to get it into pairing mode.  By now, they've all figured out how to do it without any buttons or a password.

    In what was now a battle against noise without any money or space for junk, rigged up some better speakers  with a BK8000 & the TDA1517.  The noise was worse, but the BK8000 has differential outputs while the BK3254 had single ended outputs.  The differential outputs were left disconnected in the original product to save money.

    There was an LF353 that younger lion was using to boost the input volume. The TDA1517 needed a higher voltage.

    Then the BK8000 leads just nicked a 12V rail & it was instantly dead.  The last spare bluetooth board was an ATS2815.  It had the worst noise of all & no differential outputs.  It was surprising how that cheap Vivitar had the best sound quality.  There seems to be some correlation between downmixing them to a single channel, having the amplifier surface mounted on the bluetooth board, & the noise.  They could be lowpass filtering it.

    Other ideas long ago involved dedicating a raspberry pi to the ASMR speakers.  It would entail a new phone app just to control audio in that 1 case.  It definitely wasn't worth it to try implementing a bluetooth audio stack or making a custom protocol.

    https://www.amazon.com/dp/B0DGTK6P4P

    The decision was made to burn $16 & wait a week for a won hung lo bluetooth amplifier board instead of repurposing any more scavenged boards.

    That was definitely bulkier than what lions used since 2015, but it ended the line noise.  The EQ was decent but limited probably by the speakers.  It might be time to add some kind of EQ to superplayer.  The last time lions had any kind of mega bass feature was 30 years ago.  Considering how many cheap bluetooth boards they sell, it's surprising anyone still pays for fully branded stereo components.  It's no good for a tiny portable though.

    It's 1 of those times you can't believe you went 2 years with just an amplifier chip, a headphone cable, & crummy arduino speakers.  There's no record on the goog of anyone ever using those speakers.  There was just a great challenge in developing enclosures for the vivitar speakers & a lot of uncertainty about bluetooth audio.

  • Speaker upgrade

    lion mclionhead • 03/02/2026 at 05:17 • 0 comments

    It would be all too easy to just burn $40 on a pair of off the shelf bluetooth speakers.  For the dedicated application that it is, lions just weren't happy with any cost or waiting for snail mail.  There are still 2 more unused speakers from a 2001 home theater, but they would be quite difficult to fit anywhere.

    The lion kingdom's speaker fabrication game has been horrendous.  The general problem is making the smallest air tight box for them, routing the wires out of the box.  The best drivers have no mounting holes.  Attempt 1 was caulking them in place, caulking every possible hole.  A PLA enclosure was like swiss cheese.  Taping over the panels greatly improved the sound.

    The size of the enclosure seems to depend on just how much room is required to stuff the wires & the cost of the PLA.  It's possible a larger enclosure reduces the amount of energy lost to air compression, but by then you're better off designing an accoustic transmission line.  Lacking unlimited PLA for experiments, the simplest design is the largest enclosure a lion can afford & at least enough to stuff the wires.

    The journey begins with a very compression resistant enclosure.  Getting better air tightness with a .8 nozzle printing a  .8 line width.

    Then a notch is melted for the wire.

    To create an air seal & stick the speaker on, caulking goes all over the top.  Who knows what they do in the Shenzhen holy land.

    It has to be kept upside down until it cures.  If it ends up accidentally right side up & the speaker falls in, it has to be completely disassembled & rebuilt.   Surprised it can cure inside an air tight container.  It might never cure.

    The mark 1 lion paw shapes some caulking around the wire.  It takes 12 hours to cure.  Mistakes were made, some caulking got on the vibrating parts, but these speakers actually sounded really good compared to the arduino speakers & also a lot better than their original vivitar enclosure.  

  • Bluetooth problems

    lion mclionhead • 03/01/2026 at 08:43 • 0 comments

    The mane bluetooth problems presented as line noise & power saving cutoff.  The cutoff sound level is 16/32767 & it's the same on every bluetooth speaker.  For now, it uses Ultramap to generate white noise.  The mane problem with that is when it's not playing a file or the speaker is off, the phone is constantly generating the white noise.  It really needs to be built into the music player & turned off when not playing.  There's just a little space in Superplayer to squeeze in a white noise option, but superplayer would need to be the ASMR player.  That would require it to be on a dedicated phone unless superplayer had a way to store multiple states.  It doesn't have enough room for that option.

    The line noise is more problematic. Testing with a battery showed it's independent of the power supply, RF choke, & filter cap.  It would entail digging into the ancient circuit board.  The Beken BK3254 has separate power rails for analog & digital sections but it's a piece of junk.  Lions wouldn't expect any improvement to be possible.  Bluetooth speakers aren't designed for really critical listening.  In practical listening, the noise actually wasn't audible.

    In terms of overall sound quality, the arduino speakers are a bigger problem than the line noise.  They really need more high end so the ideal solution would be obtaining a better bluetooth radio, combining it with the best amplifier, & better speakers.  

  • Bluetooth upgrade

    lion mclionhead • 02/28/2026 at 09:15 • 0 comments

    After 2 years of bad connections & wrangling the cable, it was finally time for the long awaited bluetooth upgrade.  The lion kingdom's only stereo bluetooth speaker was a terrible vivitar from 9 years ago.

    It would have been too easy to just use it intact, but it didn't have usable quality sound.  

    It previously had some bypasses to get rid of a highpass filter.

     The great challenge was eliminating the power supply noise.  It took a big cap & an RF choke.


    The mane challenge is its bluetooth advertising interferes with the other audio gear so it has to be turned off & on every day.  When it's turned off, it loses its volume setting.  Fortunately, the default setting doesn't seem to affect the signal to noise ratio.




  • x

    lion mclionhead • 10/04/2023 at 07:12 • 0 comments

    The 1st setup used some arduino speakers & an ancient amplifier based on  a TDA1517 from a soundblaster 16.  It has an LF353 for gain adjustment but no EQ.

    This setup wasn't very loud on 12V before clipping.  Seem to recall the TDA1517 getting louder with bigger speakers.  It's better than what lions had before.

    Using a spare bluetooth board would give it a power switch & more loudness.  It only burns .05W when idle & lions used to power this chip 24/7 when it was in a soundcard.  The headphone wire is a pain.  

    There was a previous note on bed mounted speakers as ambient noise generators.

    https://hackaday.io/project/138050-silly-software-wishlist/log/213734-sleep-enhancing-sound-system

    It might be easier to use an HDMI output for sound instead of the phone.  Then playlists could be played over the network.  This mode would require an easier to access volume control.

    ------------------------------------------------------------------

    They proved very effective at knocking lions out & were another example of solder dramatically affecting lifestyle.  Over the year since building the bed speakers, lion sleep patterns changed to a 1 hour nap in the daytime during peak electric prices & 1 hour less sleep at night.  The cat nap provided a lot more focus than staying awake for 17 hours straight.