Apologies for this basic question. I am sure I have read the information somewhere, but cannot recall where.
What is the recommended specification for a micro SD card for zynthian: class, r/w speed, etc.
I will try to ensure that my future questions are more interesting and challenging 
Thanks, Paul
Hi @PaulH,
I am using such kind of SD card:
https://www.amazon.com/Samsung-Class-Micro-Adapter-MB-MC32GA/dp/B0749KG1JK/ref=sr_1_6?ie=UTF8&qid=1528437575&sr=8-6&keywords=Samsung+Evo+Plus
The fact is, that the Raspi SD card reader is (AFAIK) behind the USB controller (seen from the CPU) and this is the limiting part of speed.
Also notice that you are mainly reading data and not writing. Lots of the expensive SD cards are for cams and have fantastic write speeds - but you really donât need this and can save your money for a good beer.
So take a look at the read speed and try to buy a cheaper one with a high read speed (and ignore the write speed). Just my thoughtsâŚ
Regards, Holger
I normally use SanDisk âExtremeâ & âUltraâ with very good results. Chinese ones from AliExpress also works OK 
As @C0d3man says, you should take care of having a good read speed. Write speed is important for burning fast and also if you intend to record a lot of audio on it, what i donât recommend, but i normally do ;-DD
Note than recording audio to the SD while playing big soundfonts wont work very well and you will get glitches and noises.
Kind Regards,
Thank you for your advice, gentlemen! I will take your advice, and hopefully have money left for a nice beer or two
Paul
I have a basic Sandisk Class 10 64G card - not an Ultra. It works fine for MIDI captures and all the synths seem fine as well, but audio recording stops within a few seconds of starting recording. I assume thatâs because the card is too slow.
I know this was an old thread but it still seems the most appropriate place to add this post.
A class 10 card should be capable of recording audio. I use then for all my devices which record fine. You can also record to USB if this is an issue for you by simply plugging in a USB flash.
Class 10 asserts that the card supports 10 MB/s as a minimum non-fragmented sequential write speed and uses a High Speed bus mode.
44800 samples per second, 24 bit stereo is a data rate of 288,000 B/s (0.3MB/s). Maybe your SD is near full and having to put data all over the place or it has poor write speed (faulty).
I also tested it with a USB stick with no success so obviously itâs not write speed as you suggest.
Strange.
Hi @Dithered42!
You donât specify the âcontextâ âŚ
A screenshot of your webconfâs dashboard should be enough 
Regards,
I guess that would help. 
Itâs the standard v3.
Donât spend much time on it. I will restart with a clean image in a couple days when I have better connectivity.
I tired this again with a clean Buster image.
I ran the Pure Data Generative Relaxing engine and then turned on the audio recorder with a fast 64G Sandisk USB stick mounted.
While I recorded for about a minute, there is only about 10 seconds recorded. The recording sounds normal, it just stopped recording early even though the red dot recording indicator is on for the whole recording.
Iâm running my v3 kit with the clean Buster image and Wifi on.
Any ideas?
Maybe have the web interface open and monitor the ui log while you record? See if anything crops up.
Will do.
Nothing obvious here.
Dec 28 23:14:22 zynthian startx[2670]: INFO:zynthian_layer: Preset Selected: generative relaxing (1)
Dec 28 23:14:22 zynthian startx[2670]: INFO:zynthian_engine_puredata: Loading preset config file /zynthian/zynthian-data/presets/puredata/generative/generative_relaxing/zynconfig.yml =>
Dec 28 23:14:22 zynthian startx[2670]: main_file: âmain.pdâ
Dec 28 23:14:22 zynthian startx[2670]: midi_controllers:
Dec 28 23:14:22 zynthian startx[2670]: volume:
Dec 28 23:14:22 zynthian startx[2670]: midi_cc: 7
Dec 28 23:14:22 zynthian startx[2670]: value: 64
Dec 28 23:14:22 zynthian startx[2670]: metro:
Dec 28 23:14:22 zynthian startx[2670]: midi_cc: 4
Dec 28 23:14:22 zynthian startx[2670]: value: 50
Dec 28 23:14:22 zynthian startx[2670]: random_1:
Dec 28 23:14:22 zynthian startx[2670]: midi_cc: 2
Dec 28 23:14:22 zynthian startx[2670]: value: 30
Dec 28 23:14:22 zynthian startx[2670]: random_2:
Dec 28 23:14:22 zynthian startx[2670]: midi_cc: 3
Dec 28 23:14:22 zynthian startx[2670]: value: 70
Dec 28 23:14:22 zynthian startx[2670]: freeze_verb:
Dec 28 23:14:22 zynthian startx[2670]: midi_cc: 1
Dec 28 23:14:22 zynthian startx[2670]: value: 80
Dec 28 23:14:22 zynthian startx[2670]: INFO:zynthian_engine: Starting Engine PureData
Dec 28 23:14:22 zynthian startx[2670]: DEBUG:zynthian_engine: Command: /usr/bin/pd -nogui -jack -rt -alsamidi -mididev 1 -open â/zynthian/zynthian-data/presets/puredata/zynthian_startup.pdâ /zynthian/zynthian-data/presets/puredata/generative/generative_relaxing/main.pd
Dec 28 23:14:22 zynthian startx[2670]: WARNING:zynthian_engine: Command Prompt is not defined!
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_layer: Sending MIDI CC7=96 for volume
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_layer: Sending MIDI CC1=0 for modulation
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_layer: Sending MIDI CC2=0 for ctrl 2
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_layer: Sending MIDI CC3=0 for ctrl 3
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_gui_control: SET CONTROLLER SCREEN main
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_gui_controller: ZCTRL âvolumeâ: 96 (0 -> 127), None, None
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_gui_controller: ZCTRL âmodulationâ: 0 (0 -> 127), None, None
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_gui_controller: ZCTRL âctrl 2â: 0 (0 -> 127), None, None
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_gui_controller: ZCTRL âctrl 3â: 0 (0 -> 127), None, None
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_engine_puredata: Generating Controller Config âŚ
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_engine_puredata: CTRL 7: volume
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_engine_puredata: CTRL 4: metro
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_engine_puredata: CTRL 2: random_1
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_engine_puredata: CTRL 3: random_2
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_engine_puredata: ADDING CONTROLLER SCREEN #1
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_engine_puredata: CTRL 1: freeze_verb
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_engine_puredata: ADDING CONTROLLER SCREEN #2
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_gui_control: SET CONTROLLER SCREEN Controllers#1
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_gui_controller: ZCTRL âvolumeâ: 64 (0 -> 127), None, None
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_gui_controller: ZCTRL âmetroâ: 50 (0 -> 127), None, None
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_gui_controller: ZCTRL ârandom 1â: 30 (0 -> 127), None, None
Dec 28 23:14:23 zynthian startx[2670]: DEBUG:zynthian_gui_controller: ZCTRL ârandom 2â: 70 (0 -> 127), None, None
Dec 28 23:14:28 zynthian startx[2670]: INFO:zynthian_gui: Bold Switch 0
Dec 28 23:14:28 zynthian startx[2670]: DEBUG:zynthian_gui_controller: ZCTRL âLayerâ: 0 (0 -> 10), None, None
Dec 28 23:14:31 zynthian startx[2670]: INFO:zynthian_gui: Short Switch 1
Dec 28 23:14:31 zynthian startx[2670]: DEBUG:zynthian_gui: BACK TO SCREEN => admin
Dec 28 23:14:31 zynthian startx[2670]: DEBUG:zynthian_gui_controller: ZCTRL âActionâ: 0 (0 -> 21), None, None
Dec 28 23:14:42 zynthian startx[2670]: INFO:zynthian_gui: Short Switch 3
Dec 28 23:14:42 zynthian startx[2670]: INFO:zynthian_gui_admin: Audio Recorder
Dec 28 23:14:42 zynthian startx[2670]: DEBUG:zynthian_gui_controller: ZCTRL âAudio Recorderâ: 0 (0 -> 4), None, None
Dec 28 23:15:07 zynthian startx[2670]: INFO:zynthian_gui: Short Switch 3
Dec 28 23:15:07 zynthian startx[2670]: INFO:zynthian_gui_audio_recorder: STARTING NEW AUDIO RECORD âŚ
Dec 28 23:15:07 zynthian startx[2670]: DEBUG:zynthian_gui_controller: ZCTRL âAudio Recorderâ: 0 (0 -> 5), None, None
Dec 28 23:16:05 zynthian startx[2670]: INFO:zynthian_gui: Short Switch 3
Dec 28 23:16:05 zynthian startx[2670]: INFO:zynthian_gui_audio_recorder: STOPPING AUDIO RECORD âŚ
Dec 28 23:16:05 zynthian startx[2670]: ERROR:zynthian_autoconnect: Jack Audio XRUN!
Dec 28 23:16:06 zynthian startx[2670]: DEBUG:zynthian_gui_controller: ZCTRL âAudio Recorderâ: 0 (0 -> 5), None, None
The third time I tried to record some blank audio with no synth running. When I pressed stop after about 30s it just kept scrolling the busy logo endlessly. Had to remove power to stop it. 
Thank you for trying though! The next log to look at would be dmesg and see if the kernel is complaining. If you can, ssh in and run journalctl -f --dmesg and monitor that for messages while you record.
It would seem something is going strange along the way. Is there any lower-level logging thatâs accessible for Zynthian in a release build?
Yes, if you ssh I as I suggested.
It smells like a power supply problem âŚ
Nope⌠it was a USB drive issue. After replacing the Sandisk uSD with a fast Transcend uSD I had not attempted to record internally. I only tried it with the âfastâ USB 3 Sandisk Fit drive. That fails rapidly.
I just did several recordings even up to a few minutes long on the internal uSD and that all works well now.
I assume that recording to a USB stick should work but so far it doesnât.
So I guess Iâll stick with the âriskyâ internal recordings for now.
Could be that the usb drive is trying to draw more power than the pi can provide. What is your psu?
I suppose thatâs possible but itâs a well-regulated Samsung 2A supply and a good Samsung cable. I have not seen any power supply warnings while using it so far even with the USB stick.
Iâll order a good 3A supply and see if that takes care of the USB stick issue.
