Tascam DR-70D 4-channel audio recorder (Part 8)

[voltronic]

I'm not sure if this has been asked before, but for those who use the DR70D to make 4 channel recordings, what is your method for playing back those four tracks from four separate speakers? I have an A/V receiver with separate analog inputs. But the deck only has stereo out.

You're describing something like Quadrophonic, which was a fad surround-ish technique that required 4 speakers surrounding the listener.  There are certain modern surround / ambiance recording techniques that may benefit from similar playback.

Correct me if I'm wrong, but you're not making recordings such as these; you're just using two stereo mic arrays for a concert, correct?  I do this sometimes, and you load them into your DAW and mix away but the end result is always a 2-channel stereo file.

The 70D only has the stereo out, and regardless of the number of tracks you have or the configuration of them, that output is being fed a 2-channel stereo mixdown of everything.  It's not possible to do what you're suggesting direct from the 70D, but I don't see why you'd want to.

Thanks for your reply. Yes, I'm trying some Quadrophonic recordings with 4 microphones that put a listener in the center of four surround speakers (which many people have in their home theaters). I have to load the 4-Track recordings into Audacity and burn it as a 4-channel Audio-DVD in order to review the recording on a multi-speaker setup.

But since writing my question, I remembered that you can play the DR70D recording back on a DR680 (which has six individual track outputs) if you modify the file or the folder that it's in -- I can't recall. I'll have to look it up.

Hmm, OK - I didn't expect that's what you were really doing!  Pardon me for making the assumption.  What mics and array are you using?  Something like an IRT Cross?  Also, this has to be tricky on the 70D with the lack of ganged gain controls.

The DVD-A solution is what I was thinking you'd have to do, or some other kind of surround encoding.  I didn't know about the 680 workaround.  If you have one of those, wouldn't that be easier to use for this kind of recording since you'd have the channel ganging?

[dogmusic]

I'm not sure if this has been asked before, but for those who use the DR70D to make 4 channel recordings, what is your method for playing back those four tracks from four separate speakers? I have an A/V receiver with separate analog inputs. But the deck only has stereo out.

You're describing something like Quadrophonic, which was a fad surround-ish technique that required 4 speakers surrounding the listener.  There are certain modern surround / ambiance recording techniques that may benefit from similar playback.

Correct me if I'm wrong, but you're not making recordings such as these; you're just using two stereo mic arrays for a concert, correct?  I do this sometimes, and you load them into your DAW and mix away but the end result is always a 2-channel stereo file.

The 70D only has the stereo out, and regardless of the number of tracks you have or the configuration of them, that output is being fed a 2-channel stereo mixdown of everything.  It's not possible to do what you're suggesting direct from the 70D, but I don't see why you'd want to.

Thanks for your reply. Yes, I'm trying some Quadrophonic recordings with 4 microphones that put a listener in the center of four surround speakers (which many people have in their home theaters). I have to load the 4-Track recordings into Audacity and burn it as a 4-channel Audio-DVD in order to review the recording on a multi-speaker setup.

But since writing my question, I remembered that you can play the DR70D recording back on a DR680 (which has six individual track outputs) if you modify the file or the folder that it's in -- I can't recall. I'll have to look it up.

Hmm, OK - I didn't expect that's what you were really doing!  Pardon me for making the assumption.  What mics and array are you using?  Something like an IRT Cross?  Also, this has to be tricky on the 70D with the lack of ganged gain controls.

The DVD-A solution is what I was thinking you'd have to do, or some other kind of surround encoding.  I didn't know about the 680 workaround.  If you have one of those, wouldn't that be easier to use for this kind of recording since you'd have the channel ganging?

All my good mics are only pairs and I wanted to have four mics of the same brand and model. I bought four used Behringer B-5 mics being sold locally for $40 each, as I figured it would be a good place to start experimenting, not worrying too much about the quality. Also, the B-5's have both omni and card capsules, so that was another option to be able to work with.

They are mounted in a square, about 8 inches apart, aimed outwards from each corner.

I'm currently just recording outdoors, so it's easy to get a fairly equal level on all channels because the usual basic ambient noise is about the same loudness in all directions.

Using the DR680 would of course be the best method, but it's currently in a semi-permanent installation for recording my piano. So rather than remove it for these trials, I figured I'd use the DR70D (which I enjoy using).

[Chris K]

Hey all...So dusted off the rig the other night and ran preamp RCA out> RCA-to-XLR cable> 70D XLR in using the XLR/TRS input on ch1&2, Input gain was LINE in the Input menu.

I was only about 20-25 feet from the stage/stacks. I set the Gain at low. Levels knobs were jacked with low peak levels, so I changed gain to mid. It didn't really seem to make much difference levels wise...maybe I was expecting a more drastic change. I let it ride and fixed levels in post.

I am wondering if I should have set the input gain to MIC instead of line? Or should have used RCA>TRS or RCA>3.5mm cable instead?

So...Waddaya think I did wrong? 

[lsd2525]

Hey all...So dusted off the rig the other night and ran preamp RCA out> RCA-to-XLR cable> 70D XLR in using the XLR/TRS input on ch1&2, Input gain was LINE in the Input menu.

I was only about 20-25 feet from the stage/stacks. I set the Gain at low. Levels knobs were jacked with low peak levels, so I changed gain to mid. It didn't really seem to make much difference levels wise...maybe I was expecting a more drastic change. I let it ride and fixed levels in post.

I am wondering if I should have set the input gain to MIC instead of line? Or should have used RCA>TRS or RCA>3.5mm cable instead?

So...Waddaya think I did wrong? 

99% sure that gain control only works with MIC. I believe it doesn't do anything with LINE

[Gordon]

yep!  see post about it on last page.

[Chris K]

F me...I actually switched it from mic to line.

Live and learn. Wasn't a lost cause.Recording came out ok...lower levels then I wanted but I boosted them in post.

[voltronic]

F me...I actually switched it from mic to line.

Live and learn. Wasn't a lost cause.Recording came out ok...lower levels then I wanted but I boosted them in post.

I'm curious: what preamp are you using?  I think most of us don't use external pres with the 70D the built-ins are quite good.

[morst]

I am wondering if I should have set the input gain to MIC instead of line? Or should have used RCA>TRS or RCA>3.5mm cable instead?

Running unbalanced signal into balanced XLR might make it come out -6dB lower than if you just stuck with unbalanced. (Tip-Sleeve instead of Tip-Ring-Sleeve perhaps?)
But I'm not exactly sure how the DR70D handles this, or if depends on the wiring of the unbalanced adaptor cable...
 

[Chris K]

I'm curious: what preamp are you using?  I think most of us don't use external pres with the 70D the built-ins are quite good.

JK Labs DVC...my AKG active setup....I usually run this with the M10, but left it at home so ran the 70D. I have used a rca/3.5mm cable into the external in on the 70D before. Its been a while since I used the rca/xlr cable into the 70D.

[Chris K]

I am wondering if I should have set the input gain to MIC instead of line? Or should have used RCA>TRS or RCA>3.5mm cable instead?

Running unbalanced signal into balanced XLR might make it come out -6dB lower than if you just stuck with unbalanced. (Tip-Sleeve instead of Tip-Ring-Sleeve perhaps?)
But I'm not exactly sure how the DR70D handles this, or if depends on the wiring of the unbalanced adaptor cable...
 

RCA to whatever is going to be unbalanced. I think I should have left the setting at MIC instead of Line....so long as there is no phantom power you should be able to control levels with the level knobs when in MIC position. I guess I have some experimenting to do to make sure.

[Gordon]

I run the Femto in front of mine.

[Papaphunk]

Question -

The last two times I have recorded this week, after a long duration (2 hrs - 15 Minutes ish spot last night) my recording stopped automatically and restarted in a new track file. Is there a setting I need to adjust for this so it doesn't stop and re-record without me pushing any buttons ?

I was recording in 24 bit / 44.1 khz - Plenty of room on the sd card, and my external battery was fully charged and charging the unit. It was an intertwining PTF and SMS sets with no intermission. So I was surprised to see it had automatically started a 2nd recorded file after I checked on it halfway through the show.

thanks.

[voltronic]

Question -

The last two times I have recorded this week, after a long duration (2 hrs - 15 Minutes ish spot last night) my recording stopped automatically and restarted in a new track file. Is there a setting I need to adjust for this so it doesn't stop and re-record without me pushing any buttons ?

I was recording in 24 bit / 44.1 khz - Plenty of room on the sd card, and my external battery was fully charged and charging the unit. It was an intertwining PTF and SMS sets with no intermission. So I was surprised to see it had automatically started a 2nd recorded file after I checked on it halfway through the show.

thanks.

It has nothing to do with the recorder.  WAV files are limited to 2GB, which at 24/44.1 would get you about 2:12 record time.
http://www.sounddevices.com/tech-notes/audio-recording-calculator (set to 2 GB, 24bit, 48 kHz to see where I got this)
http://taperssection.com/index.php?topic=52081.0

[Papaphunk]

^^ Ahhh Gotcha, thanks !

[aaronji]

The file size limit for WAV is 4 GB, although many recorders split at 2 GB. As I recall, this is a holdover from older FAT systems. Some recorders, such as the Marantz PMD-620/661 and SD MixPre-3/6 (and the 7-series, I think) and others, allow 4 GB splits...