Dafydd Roche #betteratelectronicsthanmusic

audioluxdevices #makemusicwiththeelectronics ;)

thekidtonystark Thanks.

Paul Stoffregen do you suppose anyone at Dialog has any interest in prompoting their codecs to the makre/arduino market?

Yann Guidon / YGDES

#nomusicwithoutelectronicsandviceversa

Dafydd Roche I do. I'm the broad market audio dude. Ther'es already an arduino board available with DA7212 on it

Paul Stoffregen I currently make an udio shield with the STGL5000 chip

Dafydd Roche http://www.dialog-semiconductor.com/content/ard-audio-da7212

The ARD-AUDIO-DA7212 is an 'audio shield' that can be used with a number of MCU development platforms due to its compatibility with the Arduino™ R3 pin layout. The audio shield can be used with commercially available development platforms such as Freescale 'Freedom', Intel 'Galileo', Microchip 'chipKIT' and Arduino.

Read this on Dialog Semiconductor >

Paul Stoffregen and a growing DSP liibrary to support it

Dafydd Roche is the SGTL part the old freescale codec?

Paul Stoffregen https://www.pjrc.com/store/teensy3_audio.html

PJRC Store

This audio adaptor lets you easily add high quality 16 bit, 44.1 kHz sample rate (CD quality) audio to your projects with Teensy 3.0, 3.1, 3.2, 3.5 or 3.6. It supports stereo headphone and stereo line-level output, and also stereo line-level input or mono microphone input.

Read this on Pjrc >

Dafydd Roche do you need linux drivers etc?

Paul Stoffregen yup, Freescale, or whoever they acquired....

Dafydd Roche check out DA7219 -- mono in, stereo out... has the 3.5mm jack detection, China/USA headset switch etc all integrated. Stellar drivers.... popular in chromebooks

Professor Fartsparkle "capless headphone driver" I was wondering why you actually need caps at all, what is the benefift of those design that use chunky caps? (total noob when it comes to audio electronics)

thekidtonystark #tryteslacoilsformusic

Dafydd Roche @Professor Fartsparkle oooooh... here we go. that plays to my strengths right here

Paul Stoffregen the DSP library runs on Teensy, not your PC. It's meant to run "in the background" while yourArduino sketch controlls everything

Professor Fartsparkle :)

Dafydd Roche most codecs are single supply. that means that to get a positive and negative swing, you have to DC bias the signal and block the DC from the headphone, or drive the speaker directkly, differentially

Dafydd Roche two ways to solve the problem. either move your 3.5mm jack GND to be VCC/2 (not a good idea)

Michele Perla are we talking about DC again? :D (just kidding)

Dafydd Roche or put in a whopping great big cap in between the chip output and the 3.5mm connector

Yann Guidon / YGDES the problem with headphones is their common pin....

Dafydd Roche you need a whopping great big cap, because the low impedance of the headphone (16ohm) creates a high pass filter.

Paul Stoffregen having now sold many thousands of those shields to makers, I'm thinking a future design will AC couple the headphone outputs. The DC offset "virtual ground" is confusing to many novices

Dafydd Roche so if you use a small cap, you end up with no bass.

Dafydd Roche perfect to balance out your beats headphones.

Michele Perla hahahahaahahahahah

Professor Fartsparkle ooh that makes sense, I never thought about that

Yann Guidon / YGDES hahahahaa

Paul Stoffregen lol

Professor Fartsparkle heh

Michele Perla that's screenshot worthy

Dafydd Roche I am now waiting for my cease and decist from apple ;)

Professor Fartsparkle lol

Sophi Kravitz lol hi everyone

Yann Guidon / YGDES they'll buy your employer and fire you themselves :-P

Paul Stoffregen looking at the DA7219 datasheet now, fwiw...

Michele Perla hi @Sophi Kravitz :)

Dafydd Roche ONLY KIDDING. We owe beats a great deal as an industry, they got everyone to rebuy headphones all over again.

Yann Guidon / YGDES i Sophi

Paul Stoffregen heya Sophi

Yann Guidon / YGDES I'll stay with Senheiser :-P

Professor Fartsparkle so how does that capless headphone driver work then?

Benchoff OMG sophi

Dafydd Roche We use a charge pump to create an negative voltage

Sophi Kravitz !! :) you guys have been talking audio for more than two hours! SOOOO aweosme

thekidtonystark Hi sophi

Dafydd Roche then output the signal, biased around ground.

Sophi Kravitz also I am glad it's still happening

Yann Guidon / YGDES Sophi : we can go on.

Paul Stoffregen it put about 1.5V DC on the headphone ground

Sophi Kravitz I KNOW

Dafydd Roche @Sophi Kravitz - sorry, I get a little wordy.

Yann Guidon / YGDES but a charge pump is noisy ?

Sophi Kravitz no no it's great

Paul Stoffregen then the 2 signals vary up and down relative to 1.5V

Dafydd Roche yes. you pay for it a little in your SNR, but your output i/V stage has feedback in it and half decent PSRR

Paul Stoffregen at least the SGTL5000 does about 1.5V. I'm pretty sure Dialog's would do something similar

Dafydd Roche We did it a long time ago - at TI I defined the PCM5xxx series of 2VRMS DAC,s and managed 114dB SNR out of a 3.3V DAC with chargepump

Yann Guidon / YGDES Paul: no, aroung 0V, not 1.5V (depends)

Yann Guidon / YGDES I would be happy to know :-P

Michele Perla +1

Sophi Kravitz +1

Yann Guidon / YGDES make a project here maybe ?

Sophi Kravitz spill!

Yann Guidon / YGDES

yeah, more beans please

Dafydd Roche the future is so bright in audio. Every year or so, I get paranoid that "we're done" in audio... then something comes along that shakes up the industry and breathes life into it

Paul Stoffregen such a tease

Yann Guidon / YGDES we discussed class D recently

Professor Fartsparkl what @Yann Guidon / YGDES said, I would love to know more about audio electronics design. Nothing better than a good project to look at.

Dafydd Rochefor example, 4 - 5 years ago, one of our smartest dudes at TI starts throwing around the concept that if we model a loudspeaker in DSP, we could understand it's current condition, and drive it harder for longer.

Yann Guidon / YGDES one of my first projects 15 years ago was a 16 bits DAC using TI chips...

Dafydd Roche that because an industry standard technology that TI, NXP, Maxim and others have

Dafydd Roche We were able to drive 300W peaks out of a 10W amplifier, and it sounded AMAZING

Michele Perla oh ok that is really interesting

Sophi Kravitz @Professor Fartsparkle agreed

Professor Fartsparklhow the hell does that work?

Michele Perl I suppose that convolution is one of the best tools that engineers have

Dafydd Roche TAS5766 now uses that technology for mid-power systems, NXP, Maxim and TI have used it for smartphones etc. -- and that's 5 year old technology. The new top secret stuff is even more exciting.

Yann Guidon / YGDES a brain is even better :-)

audioluxdevices Nice, the future is definitely rooted in modeling and simulation audio phenonoma. My niche interest is in modeling Cymatics (the science of sound and vibration made visible...). Sounds like the loudspeaker model is Cymatics in use.

Dafydd Roche and yes. I'm a tease. (all of this, so I can be invited back again some time)

Yann Guidon / YGDE you come back when you want ;-)

audioluxdevices +1

Dafydd RochViva La 3.5mm!

Paul Stoffrege not even a slight hint?

Dafydd Roch The only connector that EVERYONE knows what it's for.

Yann Guidon / YGDE yesssss

Yann Guidon / YGDES exactly :-D

Dafydd Roch @Paul Stoffregen - not yet. too soon. maybe when I have silicon.

Michele Perla *insert pass me the aux cord joke here*

Dafydd Roch Oh! Who asked about good tools? I always keep an old ipod touch at my workbench as a simple audio generator.

audioluxdevices What app do you use?

Dafydd Roch I can't use my iphone 7 - anyone know why?! :)

Yann Guidon / YGDE oh, Apple made audio generators ?

Michele Perla connectors, connectors everywhere

audioluxdevice lol

Yann Guidon / YGDES Dafyyd : I have a drill, and a 3.5mm drill

Professor Fartsparkle I have to disagree, the 3.5mm jack is also widely used as a power connector

Dafydd Roche I use a simple app called "Signal Gen" - does the job.

Dafydd Roche @Professor Fartsparkle WHAAAAAAT? Maybe if you use the mic bias ;)

Yann Guidon / YGDESno Audio Precision system ? :-D

Dafydd Roche@Yann Guidon / YGDES - sometimes you just need to see on a scope if your audio is passing

audioluxdevices *downloads Signal Gen*

Professor Fartsparkle well not using an audio source of course :p

Professor Fartsparkle but mono plugs are at least in germany often used for power supplies

Michele Perla in fact, after you told me about the Audio Precision, I was also thinking at getting a good generator

Yann Guidon / YGDES good idea

Dafydd Roche @audioluxdevices if there's a better app you find, let me know on twitter.

Yann Guidon / YGDES so now : what is a good affordable bench audio generator ?

Dafydd Roche the AP has a nice generator in it of course. but sometimes you just want something quick 'n dirty to fire into the 'scope and see if the signal is inverting, or gaining up correctly etc

Michele Perla I should grab a hi speed board adc/dac I developed for my previous company

Dafydd Roche Yann - an used Iphone! :)

Sophi Kravitz ;)

Michele Perlaand use is with the teensy

Dafydd Roche seriously - we had an apps guy years ago that debugged a chinese smartphone using an audio analysis app on his iphone.

Dafydd Roche was able to debug phase and amplitde issues with it

Michele PerlaI suppose tools are relative to the use one has to do of it

Yann Guidon / YGDESwhy not an industrial 16-bits DAC ?

audioluxdevices This looks nice too https://itunes.apple.com/us/app/signal-generator/id409241018?mt=8 (not free though)

Yann Guidon / YGDES with consumer audio you can't be sure of noise, amplitude, phase etc...

Yann Guidon / YGDES or even offset

Michele Perla for the ipod, one could just make a .wav file of a pure sinewave and play it :D

Dafydd Roche @Yann Guidon / YGDES - were you here 2 hours ago? ;)

Yann Guidon / YGDES asleep

Michele Perla he was lurking probably :D

Dafydd Roche Dang, for a dollar dude, just buy the app. your time is worth more.

Michele Perla come on :D downloading audacity takes 1 minute

Dafydd Roche one of the things I like about using an old iphone is that the device is electrically floating.

Yann Guidon / YGDES Michele +1

Dafydd Roche so you don't have ground issues (providing it's not charging)

Michele Perla true true

Michele Perla it runs from the batterty

Michele Perla battery*

Yann Guidon / YGDES but the GSM must be disabled

Dafydd Roche i use an old itouch ;)

Dafydd Roche plus, i use it for visual cues, not for proper audio tests.

Michele Perla the good old ipods were nice :) a friend of mine still uses it for music

Michele Perla you mean visual cues in the scopes?

Shulie @Yann Guidon / YGDES Transcript here: https://hackaday.io/event/25110-audio-systems-hack-chat/log/60718-audio-systems-hack-chat-transcript

Yann Guidon / YGDES Dafydd we might continue in private later because sound processing is one of my first interests :-P and I'll have to add a sound output to #WizYasep ...

Yann Guidon / YGDES Thanks Shulie :-)

Michele Perla It's been really nice to have you here @Dafydd Roche , I can't wait to see some of your weekend projects popping up :)

Dafydd Roche

audioluxdevices Agreed, thank you for your time and answering our questions.

Dafydd Roche @Michele Perla - exactly, classic example, building a small mic pre this week

Michele Perla nice :D

Dafydd Roche Quick visual cue, does the signal get bigger... throw a few 100mV's in, and get volts out. Hooray - lapel mic will be heard now by my pc!

Michele Perla yes I get it :) I would do the same

Paul Stoffregen thanks for chatting and staying late ;)

Michele Perla +1

Dafydd Roch meh, my design team is in Edinburgh. they have finished for the day :)

Dafydd Roche at least I hope they have

Professor Fartsparkle

that WizYasep sound really interesting @Yann Guidon / YGDES

Paul Stoffregen

please ping me when/if that DA7219 chip is available in a non-BGA package

Thank you so much, @Dafydd Roche!

Paul Stoffregen

I'd love to support is in the Teensy Audio Library

Dafydd Roche @Paul Stoffregen not sure we'll retroactively do it.... but future devices, if I have my way, will be available in multiple form factors.

Dafydd Roche Hey, if Raspi can be $5 with loads of BGA's, can't you do BGA's too ? ;)

Yann Guidon / YGDES I avoid BGA :-/

Dafydd Roche @Shulie Tornel - thank you for hosting me, and to all y'all for your questions and banter.

Dafydd Roche @Yann Guidon / YGDES - me too, but it's not that scary. I need practice.

Dafydd Roche DA7219 has been done so it can be soldered on a 2 layer board, using RouteEasy technology. (pins are W in formation)

Paul Stoffregen well, apparently I can do BGA (or more precisely the contract manufacturer I use), at least lower density, as Teensy 3.5 & 3.6 are doing pretty well with a BGA144 package

Paul Stoffregen but it's not just about me...

Dafydd Roche @Paul Stoffregen - I did a hackercamp in SZ a few years ago where they taught me to do BGA's

Paul Stoffregen unlike Raspberry Pi,, where you can't get the chips from Broadcom unless you make internet routers or cable set top boxes....

Paul Stoffregen people do use boards like Arduino and Teensy as the startign point for their low-to-moderate volume product designs

Dafydd Roche