Initial Tests: Using DP-24SD as an ISO Audio Recorder

[Robbie Ferguson]

Hi all,
I purchased the DP-24SD to use as an ISO recorder for my webcast. I love the idea of having an SD card after each show that has a separate WAV file for each microphone. While my show is video and these ISO recordings will replace the usual stereo mix, I'm confident this would be a great setup for Podcasters as well. 8 Mics / sources, each recorded to their own WAV file? Very nice for when someone clears their throat or otherwise adds something to the mix that is undesirable. Beyond that, I can also run each channel through the compressor independently so the levels in the final mix are entirely even (nobody's mic is louder than another).

When choosing a Tascam unit, I was initially put off by my misconception that I'd have to "export" the audio every time I want to gain access to the tracks in ISO WAV format. While this would be true if I was starting and stopping the recorder and doing punch-in/punch-out on various channels, because in my use case I am simply pressing Record, letting it run for 2 hours, and then pressing Stop, the DP-24SD indeed saves usable WAV files to /MUSIC/SONG_0001 on the SD card, one for each channel. See [this thread] which put me on to this.

Here is my test:

Using the default settings (16-bit, 44.1 KHz), I enabled ISO recording of tracks 1-4.

I began recording.

I let it run for 2 full hours.

The result is 4 WAV files in /MUSIC/SONG_0001. Each is 652.4 MB. Therefore I can deduce that I can expect to consume 325 MB per channel, per hour.

Each of the 4 WAV files can be imported to my editor no problem, and will give me significantly more control over the audio mix on my show.

Just thought I'd post this initial test result for anyone else thinking of the DP-24SD as an ISO recorder for video or podcast use.

For me, since this device can record up to 8 channels simultaneously (and separately), I'll be using 1-4 for my host microphones (headset wireless units) and tracks 5-8 for miscellaneous sources such as my laptop, Zoom interviews, and perhaps even an ambient room mic in case guests in the studio audience say something and we want to bring it into the mix.

I scored my DP-24SD as an open box return, so saved $240 on the price (CAD). I couldn't be happier so far. The build quality is superb, and it's going to make a HUGE difference to my post-production chain.

Cheers,
Robbie

 

[-mjk-]

hi Robbie, glad to hear it's working out for you.

When choosing a Tascam unit, I was initially put off by my misconception that you had to "export" the audio every time you want to gain access to the WAV files. The DP-24SD indeed saves to /MUSIC/SONG_0001 on the SD card.

We need to be somewhat careful about calling the export process a "misconception" as there are many threads about users who have tried to directly access the audio files and have run into sync issues. I understand exactly what you mean - and you are right. But if there are any edits whatsoever, or if the recording is stopped and restarted, it's essential to export the files to collate them. In your case you aren't editing and the recording is continuous. Naturally, Tascam has to recommend exporting in every case to ensure proper functionality.

Just for fun, while you're doing something else, try doing an export to see just how long it takes to export 4 tracks of audio with a length of 2 hours. There is likely going to be a time when you have some kind of a false start, and need to stop the recording and start it again. Unless you do an immediate track cleanout, or create a new Song project, you'll be faced with the necessity of exporting. It might not be such a huge obstacle to your workflow after all (as long at is doesn't take 8 hours!). But my all means, if your workflow doesn't require it, all the better!

Another advantage of the DP recorders is virtual tracks. This allows you to record something new over the previous tracks without erasing them, and maintaining the timeline. Getting those tracks out would also require exporting.

By all means, give us the link to the webcast!

Thanks.

 

[Robbie Ferguson]

Great point regarding my "misconception" statement @-mjk- -- of course, my comment is based upon my [very unique] use case. I have re-phrased the paragraph to make that more clear, and linked to the original thread where @David Porter and @Mark Richards pointed me toward the zz files.

I still have the 4x2 hour tracks on the SD card, so yes, that's a great idea: I will export those 4 tracks tonight and time how long it takes. Part for my own peace of mind (how long will this take if I ever have to do it after a show?) but also to answer the question in case any future forum guests share a similar use case -- which is bound to happen as soon as I post a review to the broadcast community

Virtual Tracks you say? I saw the button, but had no idea what it was for. Well, that could be said for nearly every button on this thing - haha! But that one stood out for sure. I will endeavor to learn the basics first, and inevitably begin experimenting with some of the more sophisticated functionality.

Thanks!
Robbie

 

[-mjk-]

Excellent @Robbie Ferguson. I myself am also interested in the time factor. Recently I did something where I recorded 5 tracks over about 45 minutes time, stopped once about 1/2 through. As I recall, it took time but also I don't have an impression that it was ridiculous.

Also, if you don't need the highest resolution and 16b/44.1kHz CD quality is good enough, that's going to reduce your file sizes by a non-trivial amount.

It's a pleasure having you on the forums, sir.

 

[Robbie Ferguson]

Heh, thanks @-mjk-

As for quality, I'm a firm believer in having my masters be the best my gear can handle. All reductions in quality will happen in post. Eg., our show is only 2k but all ISO video recordings are 4k.

But your comment does point me to the fact that I did not even think to check what the out-of-the-box quality settings were. So I will be wanting for find that and crank everything to 11!

Eager to find out how long it will take to export!

Cheers!

 

[-mjk-]

@Robbie Ferguson I share that belief too, if for no other reason than to attempt to future proof things.

It's too much to go into in a single message, but I highly recommend that you view Phil's video on using a reset template. A non-desirable attribute of the DP machines is, that whenever you make a new song project it inherits all the settings from the current project that you have loaded. And I mean virtually all the settings including equalization, routing etc. so the only safe way to start a new project with repeatable default settings of your own specification, is to first load your reset template, and then create a new song project. The added benefit of that however is that your reset template could, for example be adjusted to convert stereo tracks that you don't need into mono tracks. Plus, all your input sources can be routed to whatever tracks you need them and that is also saved in the reset template. There are a number of discussions in the stickies about this topic. That is gonna save you a lot of headaches.

 

[Robbie Ferguson]

Great tip, thanks @-mjk-

I'll be recording dry (eg., no EQ) but I do hope to add the noise reduction filter to gate channels when they are lower than the threshold (ie., that individual is not speaking). And yes indeed, I will not need any stereo channels - so I'll try to find that setting too. Sounds like having this 'reset template' will save me a bunch of time in those instances when I false start and need to create a new track. Or especially if I change settings to do something outside the norm, like those rare occasions where we record a spoof music video!

 

[-mjk-]

The stereo/mono switch is in the Assign screen.

I have a template set up for normal recording, and then I have a different template set up for overdub sessions where the requirements are slightly different. It is a significant advantage for speed.

 

[Robbie Ferguson]

Just got home and looking at the DP-24SD: looks like the default song quality settings were set to 16-bit, 44.1 KHz. So I've created a new song which is top-quality (24-bit, 48 KHz) and am recording my 2 hour test again. I want the quality to be the best it can be, and I want my tests to be realistic based on that. Eager to see the difference from my initial test.

 

[Stew71]

I've used my DP24 a handful of times in this way, recording one long take across all 8 inputs (mics, laptop, CD mixer) for a radio show.

The longest was just under 3 hours I think. I have always gone down the export to audio depot route. It does take a while, but from memory maybe 30-40 minutes or so. It's kind of unnerving while you wait though. Have a cup of tea (or indeed a full meal).

 

[Robbie Ferguson]

@Stew71 what I've learned is that in this scenario, you can completely forgo the Export. Yes, I too am seeing between 40-60 minutes to export my 2 hour test. I will be finalizing my results this weekend and posting.

Now, that said, I did my show on Wednesday and recorded 3 mics. I then removed the SD card and plugged it into my editing machine. Sure enough, the 3 WAV files were there, with no need to export! It was superb working with 3 isolated mic tracks in my video editor. Absolutely exciting!

I have a little more testing to do. The audio is falling a little out of sync with the video after ~15 minutes, and I'm going to run some tests using a beep track to see if this is due to my video (perhaps framerate conflict), or the audio from the Tascam - stay tuned - of course, my final opinion will depend on the results of that test.

But, at this point at least I have proven exporting (and waiting - which would drive me mad) is not required at all for my use case. YAY!

Robbie

 

[-mjk-]

@Robbie Ferguson how did your beep track test work out in the end?

 

[Robbie Ferguson]

Hey @-mjk- - hope you're well. Who expected a global pandemic to happen when I first started testing my new Tascam eh?

Since then, I had to move my studio (during a pandemic!) and we're hobbling along these past few months since I couldn't have contractors or even my staff on site.

So to answer your question, I setup the beep track but ended up not needing it. The problem was the SD card. I changed brands of cards and it fixed the problem. That said, the issue recently started happening again (after several months of no more issues) with the "good" card, so I may have to re-visit it, or perhaps the cards have a finite life before they start exhibiting this behavior.

Side note: the DP-24SD has proven itself to be a very effective ISO recorder. It's been wonderful pulling 4 mics off the board in post-production and using their raw WAV files independently.

Cheers & stay well!

 

[-mjk-]

Except for the global pandemic part, that is a fantastic report Robbie. Glad to hear that the DP machine is doing the job for you. Very interesting about the SD card though. Its our opinion (the ones that have pushed the DP machines hard) that nearly all issues are tied to the media, which makes total sense. In your line of work I would expect that you could stripe a track with timecode easily enough.

How are things now, after you moved?

Taiwan never had a lockdown and (embarrassingly so) it's business as usual here.

 

[Robbie Ferguson]

Yeah, when it falls out of sync, I just snip it and re-align. Never a big deal. But it worked flawlessly (no sync issues) for several months, so I may buy yet another SD card just to test the "wear and tear" theory.

Our unexpected move was an accidental upgrade, in fact. Our studio, while still slowly coming together due to the reduced availability of tradespeople, it is a big step up. We went from an old industrial room in a warehouse, to a professionally-managed office mall where we have 3 professionally renovated rooms, and a much nicer looking space with very tall ceilings.

As far as the lockdown here, it's really just been a challenge for the studio in that contractors were not allowed to work, and now that they are, they have too much to do and it's hard for them to find time to squeeze us in. We were fortunate to find a good contractor who in fact has their office in the same mall we moved into, so he has been more available than most, simply due to the convenience of being in the same building. But for 4 months, I've been the lone staff member allowed at the studio, so I've just chipped away as best I could. Still living out of boxes. We'll get there.

Stay well,
Robbie

 

[-mjk-]

Well, I gotta hand it to you Robbie, because many people feel very discouraged and are basically giving up because of the situation. But you are moving forward and upping the game. Your new studio sounds awesome. Please show us some photos in the studio section of the forum!

 

[Robbie Ferguson]

Happy to. Remind me in a few weeks when things are a bit more setup?

 

[-mjk-]

Sure thing!