adiant,

Welcome to RO

I'm guessing you are doing some sort of audio surveillance/ monitoring?

In ten years this site has been running, this is a first. Interesting question. Looking forward to how it unfolds.

(y)

"Both the Audacity and DP01 problems are caused by the 4GB limit on standard WAV files."

The problem is that the file system, FAT/FAT32, will NOT allow >4GB files, it's not a limitation of the WAV format.

You therefore need one which will record onto a REAL filesystem.
Or which can seamlessly split the files *AHHEMWONTWORKAHHEM* before it reaches the 4GB limit.

Some of the stuff you want to do can be done with this this

Hmm.

"With a 16GB SD memory card, the H4 provides up to 24 hours of stereo WAV file recording in 44.1kHz/16-bit mode"

but it doesn't say continuous recording... that would only be possible if it split the recording into consecutive 4GB files. Or smaller: as far as I remember Soundforge refuses to open wav files any larger than 2GB.

4GB gives you approx. 6.5 hours of stereo 16/44.1 recording. You could double that by recording dual mono files, but that still only gets you half way there...

I suspect that software might be your best option. eg: Reaper can split recordings into multiple files of any size you like. I've never tried this myself so I don't know how well it works, but I can't think of any reason why it should not be seamless.

Or you could record Sony Media Wave 64 files (W64). These are wav files, but with 64 bit headers. The only apps I know of that offer this format are Soundforge (they invented it) and Tracktion.

Wow! Really appreciate the responses!

I wasn't trying to hide my desired usage. The 24+ hour requirement is for what are known as Unscoped Airchecks, continuous recordings of radio stations for historical preservation, and listening enjoyment in the future, kind of like a time machine. The idea of recording an entire day of a radio station dates back at least to 1961, when a still-existing recording of Top 40 (Rock, etc.) giant WKBW in Buffalo, New York, was made. That, of course, was made with a lot of reels of tape, and well-timed tape changes that missed the centres of songs, which you could theoretically restore with a lot of effort today. More recently, on an Old Time Radio (OTR) sales site, I've seen a couple of different World War II era recordings of 24 hours of a New York network flagship station.

The 24 hour time span increased to an entire weekend as Top 40 stations began running countdowns of the Top 500 or 1000 Oldies in the early 1960s (CFUN Vancouver's Soundathon was an early example). And then the granddaddy of them all was produced in Feburary 1969 at KHJ Los Angeles: The History of Rock and Roll. It was originally 48 hours in length, with a break for live All Night shows, but it was syndicated as 52 continuous hours, and is still available to radio stations today.

Best I've done so far is 12 hours, 6am-6pm, using a pair of VHS tapes, recording 6 hours on each, on the Hi-Fi stereo audio tracks. That was back in about 2002. Problem now is that my existing VHS machines get confused by the lack of a video signal on the tapes, but that is another story.

The XLR "nice to have" is so I can also use the setup to do voice work for radio, should the opportunity present itself.

When I was originally researching the Audacity problem, I found the Wikipedia entry on WAV which talks about the 32 bit length field (2 to the 32nd power is just over 4 billion = 4GB), and then mentions W64 as a way around it. I didn't realize that W64 was so "rare". The TASCAM DP01, by the way, seems to use WAV files on its internal partitions, to record each track separately, which is why I can record nearly 13 hours of stereo before it dies.

Mulling this over during the night, I also began considering a computer-based approach. Based on my personal experience and that of friends, I am scared of using Windows because of its seemingly endless ability to find ways to wreck recordings by "getting distracted" by other work while buffers overflow. I'm not sure I can or want to afford a Mac. But, how about Linux? Can it properly handle real-time work like recording audio? Dell is selling dual-core Vostro machines, without monitor, for about $275 Canadian, which is well within my price range.

I would still prefer a stand-alone machine, but this opens up some additional possibilties.

I'll research what has been said, and be back often to see how this thread develops.

Again, I really appreciate this. Been driving me crazy for years....

Sorry, I realized afterwards that I shouldn't be discussing computer-based solutions in this "Budget Gear" thread.

adiant wrote: Based on my personal experience and that of friends, I am scared of using Windows because of its seemingly endless ability to find ways to wreck recordings by "getting distracted" by other work while buffers overflow.

If you have a reasonably clean windows installation you should be fine. If an audio only PC is not an option, consider setting up a dual boot so you can load an audio only / no internet OS for recording.

I used to have to record club nights at the venue I was looking after. These were 6 - 7 hour events running in 2 or 3 rooms: I used to record them as 4 or 6 mono 24/44.1 files using Tracktion (running in 'safe record mode' to avoid accidentally stopping recording) and never had a single glitch.

Some of the Marantz PMD line will "auto track" at a preset time interval. If these tracks are then recombined in a DAW they are seamless recordings. This might be an option. Inputs are spdif, standard rca, and XLR. It can be run in stereo or mono mode.

Marantz PMD620

The manual for the Marantz PMD620 sure makes interesting reading. The AutoTracking facility you mention, where a new file is automatically created during a recording session at a specified time interval, includes a setting for 24 hours, which indicates to me that someone has actually thought about recording more than 24 hours continuously.

On the downside, I'm hoping that the statement "The continuity of sound is not guaranteed and depends on the speed of a card or the audio file size." is merely legalize to protect against really slow SD cards.

Marantz is also offering a $100 mail-in rebate on this item right now, making it even more attractive.

I was also a little worried about the fact the manual didn't show anything larger than a 4GB SD card in its Recording Time charts. Until, that is, I saw an FAQ item on the Marantz web site that says the PMD620 supports 2TB SDHC cards. Now, if they only would tell me where to find one.....

I have a modified PMD 671 and I use type II CF 4gig cards. This is a back up device for me or for down and dirty 2 track classical recordings. I had a concert I recorded where a "helpful" elf had turned on the auto track feature. The default setting was 10 minutes. I ended up with about 10 or 11 segments that I connected in Audition 3 and there were no problems at all. I can see how a slow card might be a problem but I didn't experience this. Also, I have read of problems with the micro drives so I would avoid them.

I believe if you purchase any Alesis HD 24 & instruct it to only record 2 tracks, a 400 Gigabyte Drive may actually do it for you?

HD 24xr owner
Ms. Remy Ann David

RemyRAD wrote: I believe if you purchase any Alesis HD 24 & instruct it to only record 2 tracks, a 400 Gigabyte Drive may actually do it for you?

HD 24xr owner
Ms. Remy Ann David

One of his needs was that it would not cost more than $350 and unless the price has dropped an HD24 is not even in the ballpark.

Surely this is an application where compression in its many flavours (ATRAC, MP3, Ogg etc) comes into its own. I don't normally champion compression schemes, but they can have their place. The balance between file size and audio quality can be adjusted by selecting a bit rate that would give you the required 24 hour record time with a file size that the recording device can handle.

I appreciate all the help.

Compression is a great idea, but the most respected website for preserving historic airchecks (reelradio.com) is run by a perfectionist who insists on uncompressed material. Or, for analog material, the analog master so he can digitally master it himself. For example, for tape, he even goes as far as misaligning the tape heads to match the original recorder.

Given that I'm trying to preserve for the future, I also realize that even just 10 years from now, storage will be so cheap that no one will understand why there were any issues in recording less than 44KHz 16-bit WAV.

In fairness to the above mentioned perfectionist, he also won't accept any recordings of the Internet streaming of a radio station. Has to be off the air. Or better yet, recorded directly in the studio. I currently do most of my recording off the studio feeds picked up by my local cable provider and fed on the FM frequencies of my cable television feed. They even provide AM stereo when available. I'm also looking at an amplified tuned loop antenna to get clean reception of AM stations not carried by my cable provider.

As for historical material, I have a fairly large collection of analog material that I want to digitally remaster myself. Nothing 24 hours, but I do have one 10 hour VHS tape. Reel to reel tape, VHS hi-fi tracks and cassettes. It is becoming clear to me that I need to get it done fairly soon, as some is breaking down from old age, especially what I acquired from others who did not care for it properly.

Well if we can't use compression, what about some kind of lossless format? FLAC comes to mind...

-N

FLAC is good...I get to about 45% original size usually.

I just ordered a Marantz PMD620 after receiving the following response from their technical folks, when I asked about 44KHz 16-bit stereo PCM/WAV recording:

The PMD620 can record for 36 hours continuously. Please note that the machine will make a new file every time 4.3 gigs is reached during the recording.

Found a U.S. authorized dealer selling it for $322 U.S., including free shipping. And Marantz has a $100 mail-in rebate until the end of March for U.S. street addresses.

I've got a line on a local fellow who is selling an HP 32GB SDHC card for what sounds like a good price (I'm still negotiating), which will give the PMD620 the ability to record for over 54 hours continuously. If that doesn't work out, BCom locally sells Kingston 16GB SDHC cards for $38.88 Canadian, as that will give me 27 hours.

In response to my reporting of an Audacity 1.2.6 (latest non-Beta version) bug that writes out invalid WAV files when you exceed the 4GB limit, the developers responded with a warning that Version 1.2.6 also has a 2 billion (thousand million in the U.K.) samples limit.

I would caution that all SD cards are not created equal. Make sure it is a high-performance model that has above average data transfer rate.

Good luck, keep us posted on your results.

Lots to report, and I did promise to update this thread after I had gathered some experience on long recordings with the PMD620. I have discussed some issues in other threads, but will repeat myself briefly here just to keep this all in one thread.

I will start with the lastest News first, as it is the most relevant. I just completed a 24 and a half hour continuous recording of some radio station in Spokane, because it was the cleanest signal I could find on cable FM. As promised by Marantz, the PMD620 did start a new file, but at the 3.72 GB mark, which equates to 6:17:55 in 16-bit 44KHz stereo WAV (PCM) format.

But, when I very precisely put the end of one file and the beginning of the next together, using Audacity down to the millisecond level view, the results were both revealing. And disappointing. At least two seconds of audio was missing, and there was about half a second of silence at the beginning of the next file.

This is with the latest Firmware, A2.33.

As reported elsewhere, dvdhawk is correct. SDHC cards are not all equal. But, surprisingly, a Class 2 (SanDisk Ultra II) card works, but a Class 4 (Kingston) fails. Marantz Support strongly recommends SanDisk and Lexar, and has had lots of reports of trouble with Kingston. Kingston Support says that they have never tested a PMD620 with ANY of their SD/SDHC cards.

I initially bought a 32GB "Kingston" card on eBay, but it turned out to be counterfeit -- actually a no-name 1GB card that had been reprogrammed to look like it had 32GB capacity. I got my money back, but 24 other suckers didn't.

The PMD620 that I bought new in March had firmware that was 2-3 years old. And had lots of problems until I upgraded the firmware. Reading the "what was fixed" for each new firmware version is very enlightening, as it highlights a huge number of problems. But I haven't run into any other problems with the current firmware.

I'll update again after I hear from Marantz Support about the "not seamless" move from one file to the next at the 3.72 GB mark.

On the PMD 671 it has a "Pre Rec" feature that when on records a four second cache of audio constantly in preparation for recording. This feature would ensure you didn't drop two seconds out of your segmented program. At least it has for me when I accidently recorded seven 10 minute sections of a chamber recital. It did splice together nicely.

Autotrack=6 hours

I found a solution! If you set the Auto Track to 6 hours on the PMD620, it does a seamless switch to a new file, without losing any audio at all. I just finished reviewing the test recording I made.

I still plan to report the problem to Marantz Support, in hopes that they will fix it in the next Firmware release.