Hey guys.. I've been recording with a Marantz PMD-661. It's been fine since I got it a few months back until recently where my recordings for a few seconds here and there sounds like the device is underwater... any ideas? I tried changing the batteries. It's happening on both the on-board stereo mics and with my Rode NTG-2 shotgun. My on-board mics look clean. HELP??
Marantz recording sounds like it's underwater
- Thread starter jayrock
- Start date
JordanBlock
Well-known member
Have you confirmed that you are not, in fact, underwater?
Seriously though, try different recording settings, try to determine if it's both channels or just one, try other mics/cables just in case, post a clip ( http://www.senduit.com/ is great for this), maybe it's something one of us has heard before and knows how to fix.
Seriously though, try different recording settings, try to determine if it's both channels or just one, try other mics/cables just in case, post a clip ( http://www.senduit.com/ is great for this), maybe it's something one of us has heard before and knows how to fix.
Noiz2
Sound Ninja
What are your recording settings? If your recording MP3 it could be encoding artifacts. I had this happen with MiniDisk and people with HD camcorders that record compressed audio have also reported the problem. If that is it it will be related to the kind of sound you are recording. Doppler car horns and bagpipes are two pretty sure things that will cause problems.
Ok, so I have 3 presets.. all of them yields the same "underwater" / "warble-y" sounding distortions in my audio. I'm not recording mp3, just wav.
Preset 1 (Shotgun mic) - PCM 24bit, 48khz, Mono, Manual level. For this preset, I use the RODE NTG-2 with phantom power on, no battery inside
Preset 2 (Internal mic) - PCM 24bit, 48khz, Stereo, Auto level on
Preset 3 (Internal mic) - PCM 24bit, 96khz, Stereo, Manual Level
I will upload audio samples later.
Preset 1 (Shotgun mic) - PCM 24bit, 48khz, Mono, Manual level. For this preset, I use the RODE NTG-2 with phantom power on, no battery inside
Preset 2 (Internal mic) - PCM 24bit, 48khz, Stereo, Auto level on
Preset 3 (Internal mic) - PCM 24bit, 96khz, Stereo, Manual Level
I will upload audio samples later.
Not only is the memory card providing storage, it has to provide that storage at a throughput speed high enough to keep up with the bitstream traffic coming in. It's same reason why we need to use class 10 SD cards in our DSLRs when shooting video. The Class of the card represents the throughput capability. It's also why it's common to use raid storage systems for editing computers. To keep up with the massive amount of data traffic being moved thru the system.
So, if the card is damaged or flawed, it can't keep up with the dataflow, and only portions of the data are captured. Since the stream is digital, there's no telling what parts of the data packet will be omitted and how those omissions will manifest themselves when the file is opened (i.e. frequency, amplitude, phasing, etc.). Essentially, when enough data is dropped from the stream being captured, the resulting playback is, well, gobbledegook.
So, if the card is damaged or flawed, it can't keep up with the dataflow, and only portions of the data are captured. Since the stream is digital, there's no telling what parts of the data packet will be omitted and how those omissions will manifest themselves when the file is opened (i.e. frequency, amplitude, phasing, etc.). Essentially, when enough data is dropped from the stream being captured, the resulting playback is, well, gobbledegook.
Noiz2
Sound Ninja
Also if the card is bad it may not be recording an accurate copy of what it is sent. Scramble the data and i will definitely affect the sound.
I understand the notion of appropriate class card, but we're talking a voice recorder, not a video recorder. Maximum bitrate in the PMD661 is 4.39 Mbps (96 kHz 24-bit 2-ch Linear PCM) or 0.55 MB/s, which is less than Class 1 or 6x. Pretty much any generic SD card shall do the trick... unless, of course, the card is dodgy.
Is it possible to still capture the audio stream partially and retain the file integrity (for playback) because the storage medium is slow? I doubt that the recorder would gracefully handle (degrade or cache) the stream just to write something. It would throw an error. And the SD card, obviously, does not have any intelligence to ensure audio file integrity on its own.
While I understand the attempted explanation, I am confident that the recorder would either skip portions of the audio stream or throw an error if the storage has inadequate performance. But distorting the properties of the audio stream while retaining the file integrity is difficult to pin on the slow SD card.
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Noiz2
Sound Ninja
Well what do you suppose it would sound like if the recorder was tossing away little bits of information so the card could keep up? I'm guessing it might sound like over heavy noise reduction, which is doing essentially the same thing. Over processing with noise reduction gives you an "underwater" kind of sound.
But this is kind of silly speculation. The recorder must spec a card class for the recorder. If the OP was using the right class of card then it was probably a dodgy card, if he was using a lower class then it might be that the card was too slow or it still might be a dodgy card.
Unless someone can do a lab test to see what that recorder does with a card that is too slow it's all debating how many angels can fit on the head of a pin.
What I do know from long experience is that when audio data gets screwed up it can come out sounding like just about anything.
I understand your points and agree. I do not think any professional recorder by design would toss any information from the stream just to write something on the card. The logical behavior is to throw an error to inform the operator about the problem so it can be addressed instead of keeping recording degraded sound (as if nothing happened) and, quite possibly, ruining any chance of useable sound capture. No recordist would agree to such a "feature." But again, as you said, it is a speculation without testing or manufacturer's clarification. Still think that the issue has a big chance of being a glitch in the recorder engine or degraded external sound equipment or conditions (e.g., mics, mixers, preamps, cables, interference, user error).
Noiz2
Sound Ninja
I think you are probably correct and it's a dodgy card. But this is not exactly what most professionals would call a "professional recorder". It's basically about on the same level as an old Walkman DAT. They were used by a lot of professionals but it was definitely a consumer device. So I would be a bit surprised but not shocked if didn't throw an error. I do think the PMD671 throws an error if the card is too slow.
On the other hand the HHB DAT recorder, a very $$$ professional recorder, had a quirk where if you got past the recorded part of the tape it would go into record and TC would count merrily away but you recorded nothing. Big surprise when you get back and try to transfer.
Actually with flash recorders the card is one of the first things to check. They go bad periodically and the symptoms are not always all that obvious. Because of the sound he described it would almost definitely be a digital issue. So card or recorder.