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Silence is not golden. wav file w no sound from ZH4n.

Posted: Thu Apr 12, 2018 12:45 pm
by tdillnyc
Need help troubleshooting.
Recorded an hour long interview at a co-working podcast studio w their Zoom H4. When finished I tested it and it played back loud and clear. Went home and put the SD card in my Zoom H4 and hear nothing but silence. The file (MONO-000.wav) has 912MB w a duration the same length as my interview. I dragged it into Audacity and Garageband and still nothing. I tried importing as raw data in Audacity with same result, nada. Any suggestions out there? Thanks in advance.

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Fri Apr 13, 2018 5:10 am
by sciurius
Could it be that you removed the SDcard without properly shutting down the H4n?

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Fri Apr 13, 2018 7:59 am
by tdillnyc
Possible. But if that is the case am I out of options to recover the data/audio?

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Fri Apr 13, 2018 9:03 am
by Wulfraed
tdillnyc wrote:
Fri Apr 13, 2018 7:59 am
Possible. But if that is the case am I out of options to recover the data/audio?
First thing: Do not do anything that writes to the SD card! If you are lucky, the directory does mark the full file, but if it doesn't, a write could result in wiping out part of the data. Best case is that only the file header information failed to get updated.

https://www.techwalla.com/articles/how- ... t-wav-file
https://www.sweetwater.com/forums/showt ... epair-help
https://www.pro-tools-expert.com/home-p ... -work.html


http://www.railjonrogut.com/ (scroll down the left to find the link leading to...)
http://www.railjonrogut.com/WAVSaver.zip

If those hints don't help, you may need to try a deleted-file recovery program.

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Fri Apr 13, 2018 10:15 am
by tdillnyc
Thanks. I'll give these a try this afternoon. Fingers crossed.

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Fri Apr 13, 2018 12:58 pm
by tdillnyc
I'm afraid the above techniques did not work. Any other suggestions?

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Fri Apr 13, 2018 1:51 pm
by sciurius
Can you make an image copy (a block-by-block) of the SDcard just in case?
Then try the SDcard in the original H4n?

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Sat Apr 14, 2018 7:51 am
by tdillnyc
How do you make an image copy?

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Sat Apr 14, 2018 8:09 am
by sciurius
Assuming you use Windows, I would not know.
Try google "image copy usbstick".

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Sat Apr 14, 2018 8:14 am
by still_fiddlin
Old thread about invalid file import problems, which doesn't sound like the case here, but you might try using Audacity to see if there's anything there.

viewtopic.php?f=15&t=24018

The problem with SD cards is the wear-leveling that goes on, which moves logical sectors around to normalize the usage of blocks of memory, so a block read only works if the card hasn't been had anything moved around by the controller after recording. There's no spec (AFAIK) as to when this occurs, so even a power cycle, e.g., moving the card from on device to another, could have triggered a move. The original data could be anywhere.

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Sat Apr 14, 2018 9:25 am
by Wulfraed
still_fiddlin wrote:
Sat Apr 14, 2018 8:14 am
There's no spec (AFAIK) as to when this occurs, so even a power cycle, e.g., moving the card from on device to another, could have triggered a move. The original data could be anywhere.
While there is no specification (and really cheap cards may not even contain wear-leveling), data should not move just from cycling power.

The way the memory cards function is that writes can only turn 1-bits into 0-bits, and such writes can operate on smaller blocks (sectors, if you will). But to reuse any block requires copying it (technically, if the rewrite does not try to turn any 0-bits back to 1-bits one could do a direct write) to a new allocation unit (allocation units are much larger than the write blocks, so lots of data may be copied -- basically any "used" blocks in an allocation unit need to be copied while empty (formerly used) are left ready for writing). Wear-leveling takes place at the allocation unit level -- the "erase" phase may occur before the allocation unit is written to, or after it has been copied from.

One facet affecting wear is how many allocation units the card can keep in an "open" state (buffered in controller RAM, say, or just a table of active positions...). Cheap cards (and the spec for Class-10*) are such that a controller may only be able to handle 2 allocations units at a time, and closing/opening a recording requires flushing allocation units (close file, open FAT to update directory, close FAT, reopen files for playback) triggering wear-leveling moves on each. Higher-end cards can have up to 6 allocation units active, so result in fewer moves, and faster performance on smaller files.


* Class-10 cards are rated for streaming a single video to a freshly formatted card (write) and playing it back. Class-2/4/6 are rated allowing for fragmentation -- what would result from still-image photography where-in the user may have deleted some images (leaving "holes" to be filled by later files), or an MP3 audio player (while playback should not result in wear-leveling moves, the piecemeal adding of songs to the card could trigger some). For these reasons, a high-end Class-6 can outperform a plain Class-10 on devices that are generating multiple files at once (multi-track recording) since, even if the audio data for the files is inter-leaved, the FAT likely gets updated for file size after each buffer flush -- and the allocation units having the file headers has to be reopened (hence moved) to allow for the internal length data to be written.

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Sat Apr 14, 2018 10:00 am
by still_fiddlin
Well, something has happened, or perhaps we're all confused about what was done with the original recording if it played back Ok on the H4 that was used to record it!

I've never used the MONO mode of recording, which is what would create a file with that name. Not sure if the original recording was done with the built in mics, but this suggests 1 external mic was used. Perhaps there was more than one file created?

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Sat Apr 14, 2018 11:59 am
by Wulfraed
tdillnyc wrote:
Thu Apr 12, 2018 12:45 pm
Recorded an hour long interview at a co-working podcast studio w their Zoom H4. When finished I tested it and it played back loud and clear. Went home and put the SD card in my Zoom H4 and hear nothing but silence. The file (MONO-000.wav) has 912MB w a duration the same length as my interview. I dragged it into Audacity and Garageband and still nothing. I tried importing as raw data in Audacity with same result, nada. Any suggestions out there? Thanks in advance.
912MB seems a bit large for a MONO file, if the recording is only an hour long... Audio CDs -- 44.1kHz, 16-bit, STEREO are only 700MB for an hour.

I also note that the subject states H4n, but the body text just says H4 for origination and destination. The original H4, if I read the manual properly, used STEreo and, in multi-track mode, TRacK file names. No MONO. Multitrack files are 16-bit, 44.1kHz. Stereo mode can be 44.1/48/96kHz

For the H4n, stereo mode files are, again STE, but can be 16/24-bit, 44.1/48/96kHz -- although if on has MONO-MIX (which just combines the left/right inputs, and sends the same data to both sides of the recording) does use MONO. Multitrack uses TRK.

So... assume worse case -- 24-bit, 96kHz, Mono-Mix active (which means the file is still a stereo file):

24bits * 2channels * 96_000samples/second => 4_608_000 bits/second * 60 seconds/minute * 60 minutes/hour => 16_588_800_000 bits/hour / 8 bits/byte => 2_073_600_000 Bytes/hour => 2_025_000 kB/hour => 1_978 MB/hour...

Assume 48kHz... That would give 987MB/hour... That is closer to what you state. Or 44.1kHz, but still 24-bit -- that comes in at 908MB/hour

If you can specify the bit-depth, sample-rate, and channels for that "raw" import declare it to be 24-bit 48-kHz Stereo (two channels) or 24-bit 44.1kHz. Then start playing with offsets to find the start of the data... Did Audacity show anything in the waveform? (I just imported a JPEG image in RAW mode -- yes, it is a lot of noise, but the wave form at least shows varying data). If the wave form is totally flat, I'd suspect your size information is from a FAT directory entry or SD card allocation unit mapping that did not get updated correctly, and is pointing to an erased allocation unit (or a lot of them -- as erasure to all 1 bits may read as signed -1).

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Mon Apr 16, 2018 1:31 pm
by tdillnyc
Both Zooms were H4n's. The original recording was done with 2 external mics. I did a quick test before I even started and that test did play but that file has never showed up. When I came home I had only one file on the SD card and that was the hour plus 912MB wav file.

Info of the file reads: 2 Audio Channels, Sample rate: 48,000, Bits per sample: 16.

Audacity waveform was flat w/ no varying data. I played with a bunch of alternate settings and the best I got was all out distortion w/ no waveform data.

Sounds like I'm screwed with this particular recording. Thanks to all for trying.

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Mon Apr 16, 2018 2:09 pm
by Wulfraed
The only thing left is to find some file-recovery software and let it see if there is a "deleted" file somewhere on the memory card. This will have to run on the actual card (unless you mastered making block images [win32diskimager]).

Not an endorsement -- just the first non-advert hit in Google: https://www.easeus.com/data-recovery/ca ... eeware.htm

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Mon Apr 16, 2018 3:54 pm
by still_fiddlin
tdillnyc wrote:
Mon Apr 16, 2018 1:31 pm
Both Zooms were H4n's. The original recording was done with 2 external mics. I did a quick test before I even started and that test did play but that file has never showed up. When I came home I had only one file on the SD card and that was the hour plus 912MB wav file.

Info of the file reads: 2 Audio Channels, Sample rate: 48,000, Bits per sample: 16.

Audacity waveform was flat w/ no varying data. I played with a bunch of alternate settings and the best I got was all out distortion w/ no waveform data.

Sounds like I'm screwed with this particular recording. Thanks to all for trying.
There's so many things wrong here it's impossible to understand what could have happened.

If you did a test recording on the same SD card, i.e., stopped, and played and restarted, unless you reformatted, the second recording should have shown up as *001.wav. The fact you only have a *000.wav file suggests that it wasn't stopped and restarted. (The Zoom manual actually says numbering starts with 0001!)

And, if there were two mics, why was it set to MONO mode? It makes no sense. (Actually, one possibility it suggests is that MONO mode was selected and the left, external mic level turned down to zero, or perhaps the mic turned off, because that's the only input recorded in that mode, per the manual.)

Now, maybe there's a couple of files in a folder somewhere on that SD that remain undiscovered, but it sounds like a CF to me.

I'd suggest getting intimately familiar with your own H4n, practice using it, and only use your own recorder for your recordings. Then, take notes on what project folder is being used and the track names that are being written, with a short note about record levels observed. I have a little notepad and do this every time I do onsite recording, along with a little checklist of things to tick off (like are the appropriate red lights on, the record timer advancing, record time/space and battery adequate, etc.) before walking away from the recorder thinking it's actually doing something.

When I get home, I take the SD card and put it in my computer and copy the files into a project in the DAW first thing so it's backed up there before I even turn on the Zoom again.

Re: Silence is not golden. wav file w no sound from ZH4n.

Posted: Mon Apr 16, 2018 4:40 pm
by tdillnyc
I am just as perplexed. I've made some dumb mistakes in previous recordings so I do all the checks you mentioned. Like I said before. I did a quick test before I started and listened to the first 20 seconds of the recording when I finished so seeing that I only had one file that didn't play at all when I got home set this whole thread in motion.