Zoom H4n Pro file recovery after sudden power loss

I’ve been using a Zoom H4n Pro audio recorder for a few years now. I like that it’s durable, relatively inexpensive¹ and doesn’t look too fancy. Those last two points are very important when I set it up on the New York City sidewalk across from my bands² while I’m playing. It doesn’t catch anyone’s eye and if it does it’s easily replacable.

There are a few things I don’t like about it. The rubberized coating gets gross³, the menu system is convoluted, it chews through AA batteries… and if it loses power while recording it loses your files.

To prevent a power loss I strongly recommend powering it off of a 5V USB port, either from a wall outlet or a rechargable battery pack (Pictured above) with a USB to barrel jack adapter AND with AA batteries in the recorder. The recorder will draw power barrel jack and will fall back to the AA batteries if needed.

If your recorder does lose power while recording your files are probably still recoverable. Here’s how I recovered a 24-bit stereo WAV file recently.

Notes

• Only 1- or 2-channel audio files. For 4 channels read merethan’s guide linked below
• This is for MacOS specifically: The same general process is relevant to Windows and Linux, you will have to figure out a different way to make an image (ISO) out of the SD card
• MacOS Terminal: These instructions assume familiarity with the terminal. If you don’t know what that is or are not comfortable following instructions I recommend asking or paying someone else to do this for you.
• Only for WAV: I do not know if this process will work for variable bit-rate MP3 files. I have only tried with WAV files.

Recovery Process

1. THIS IS VERY IMPORTANT: DO NOT SAVE ANYTHING ELSE TO THE SD CARD.
2. Connect your sd card directly to your computer.
3. Identify the path to the device by opening Terminal. On Mac the command is diskutil list
   Look for a path like /dev/disk8 with the correct value in the “SIZE” column

4. Create a byte-for-byte replica of your SD Card. This will be exactly the same size as your SD card so make sure you have enough free disk space. Some instructions recommend using Disk Utility but as of MacOS 15.6.1 I couldn’t figure out how to make a full disk image that way.
   
   sudo dd if=/dev/disk8 of=~/Path/to/save/your/sd/card/image/zoom_sd_card.iso bs=512

5. REMOVE THE SD CARD FOR SAFE KEEPING. DO NOT TOUCH IT AGAIN UNTIL YOU HAVE YOUR FILES

6. Figure out what your audio recording settings were. If you have another recording you made with the same device with the same settings you can use open it in MediaInfo to see. Look for “Channels”, “bit rate”, and “bit depth”.
   
   If not you can try putting a different SD card in your Zoom and checking the format to see what was selected by default.

7. Make sure you have a lot of disk space for Audacity’s temporary files. I needed a full 45 GB free for a 16 GB sd card

8. Open Audacity

9. File > Import > Raw Data…

   • Encoding: Signed ??-bit PCM
?? is the bit rate you found in step 5
   • Byte order: Always “little endian”
   • Channels: The number of channels you found in step 5
     This guide is only applicable to 1 or 2 channel audio. For 4 channels read merethan’s guide linked below
   • Start offset: Start with 0, finish the instructions, then come back and try 1, 2, 3, and 910
   • Amount to import: If all of your recordings were made with the same settings you can set this to 10% to see the first part of your disk image allowing you to check if you got it correct in Audacity. If your recordings have different settings you’ll just have to use 100% and inspect the disk image manually
   • Sample rate: Set this to “bit depth” you detected above. Note that Audacity wants Hz and MediaInfo uses kHz (44,100 Hz = 44.1 kHz)

9. WRITE DOWN WHAT SETTINGS YOU USED
10. Press import and get a snack
11. Turn down your speakers to a quiet level. There will be loud annoying garbage. Headphones NOT recommended.
12. Look through your file for something that looks like an audio recording. Try playing it. If you find part of your recording select it and export it to a safe spot (NOT YOUR SD CARD. NO WRITING TO THAT!) with the same settings you originally recorded it with. I recommend leaving some wiggle room on either end of the recording that you can trim down later.
    
    NOTE: Your recording might be in a single continous piece or it might be split up.
    
    Stuff that sounds like garbage are non-audio files or audio files that were recorded with different settings.

13. Write down what you found with these settings.
14. IF YOU DID NOT FIND EVERYTHING DO NOT PANIC.
    • Quit Audacity with Command-Q (⌘Q)
    • Make sure you have the expected available disk space. If your disk is suddenly full it might be an Audacity recovery file. Delete any large files lingering in /Users/YOUR_USERNAME/Library/Application Support/Audacity/SessionData
15. Return to step 9 and change the Start offset, then repeat the remaining instructions.
16. Once you have found everything you can recombine it

Good luck!!

The following guides were invaluable:

• merethan’s Zoom H4n Recovery Guide: GitHub. Good explination of what is happening at a low level. If you’re trying to recover a 4CH recording you should read this!
• James’ guide Reposted by chris kehnle. The original appears unavailable.

It’s well known that hard drive prices have been rapidly increasing. Here’s my personal experience.

In November, 2024 I bought a bundle of two 16TB WD Red Pro NAS Hard Drives directly from Western Digital. The list price was $670 but there was a promotion for the bundle bringing the price down to $500. Tax was $45 and shipping was free. That works out to $272 per drive ($17/TB).

The same drives are now listed for $400 on WD’s website ($25/TB). Diskprices.com (Archive.org snapshot of today) says the lowest price available for a new 16TB drive is $360 ($22.5/TB). Amazon has them for $578.

^ Amazon price history (source: Keepa)

Prices fluctuate, of course, that’s annoying but not so strange. The fact that everything is out of stock seems stranger to me. I was thinking about upgrading some drives and selling the used ones to my coworker but that doesn’t seem feasible now.

The same is true for flash storage and SSDs. I know a video editor who likes to work on 4TB Samsung T7 USB drives. In November, 2024 they cost $279 each. Today they cost $664 on Amazon and $880 on B&H. At least they’re on the shelves, I guess.

I’m not sure where this is going but it seems like prices will keep going up for the immediate future. At this point I’m nervous about SD cards and routers too.

Grace Bowers at Night Club 101 on March 16th, 2026

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Gladiators NYC in Central Park back on November 11th, 2025

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Posting these graphs so I can easily reference them next time they come up in conversation

Climate graphs from Weather Spark (NYC, Arroyo Grande)

Ocean temperatures from Surf-Forecast.com (Asbury Park, Pismo Beach)

Relisten.net I just discovered Relisten (via a post about gapless.js on HN) a website with a slick multi-column layout for browsing live music recordings on Archive.org. I somehow missed this in my search for prior art while building my own Archive.org audio player.

Relisten is built by a different Daniel in Brooklyn. Hello, Daniel! 👋

XKCD 949 from September, 2011 still rings true 15 years later.

In my case, I want to share photos and videos with my friends, family, and strangers at full resolution. My experience is iPhone-centric. Here’s a quick rundown of my findings (as of March, 2026)

If I could impart one important point it’s that you cannot rely on file storage you do not pay for. If someone share something with you, download it!

1975 University of Connecticut Marching Band

01-The 1975 Pre-Game Show

3:40

02-1975 Street Series - UConn Husky

1:31

03-1975 Street Series - Old Connecticut

1:47

04-1975 Street Series - The Stars and Stripes Forever

3:26

05-1975 Street Series - The Star-Spangled Banner

1:80

06-Captain from Castile

1:60

07-The Stevie Wonder Show - Up Tight

1:53

08-The Stevie Wonder Show - Don't You Worry 'Bout A Thing

1:54

09-The Stevie Wonder Show - Higher Ground

1:36

10-The Stevie Wonder Show - You Are the Sunshine of my Life

2:49

11-The Bruckner Show - Scherzo, Symphony IV; King David; Chorale; Nights in White Satin; Candide, Overture; King David, Finale

11:00

12-Knock Three Times

1:20

13-"The Bitch is Back" Show - The Bitch is Back

0:36

14-"The Bitch is Back" Show - How Can I Be Sure

2:60

15-"The Bitch is Back" Show - Call on Me

2:32

16-"The Bitch is Back" Show - Come Rain or Come Shine

2:26

raw_audio

55:36

Hosted by the Internet Archive ⓘ

This is a part of a series where I digitize vinyl records. More UConn records / all records!

1965 University of Connecticut Marching Band

1/21

Fanfare #5

0:12

2/21

Temptation

1:45

3/21

Joshua

1:27

4/21

Lover

1:90

5/21

Saints in Concert

2:55

6/21

Bugler's Holiday

1:30

7/21

Latin Prelude

2:40

8/21

Keep on Dancing

0:45

9/21

My Fair Lady

3:00

10/21

That's Entertainment

1:13

11/21

Moon River - Pink Panther

2:33

12/21

See You In My Dreams

1:10

13/21

Fanfare #1

0:39

14/21

UConn Husky

1:34

15/21

Old Connecticut

1:29

16/21

Fight Connecticut

1:00

17/21

National Emblem

2:59

18/21

Them Basses

2:55

19/21

American's We

3:19

20/21

On The Square

2:50

21/21

Hosts of Freedom

2:11

01

Raw audio

43:36

Hosted by the Internet Archive ⓘ

This album is notable for track 16, “Fight Connecticut”, which hasn’t appeared anywhere else yet.

This is a part of a series where I digitize vinyl records. More UConn records / all records!

Notable Local Bird Sightings from eBird I’ve made some improvements to my eBird TRMNL plugin that displays notable birds in your area! All you need is a free account and then you can generate an API key. The plugin will do the rest!

The API docs define “notable” as the following:

Notable observations can be for locally or nationally rare species or are otherwise unusual, for example over-wintering birds in a species which is normally only a summer visitor.

This is one of several TRMNL plugins I maintain! Find them all under the tag TRMNL