Topic: Tascam DR-70D 4-channel audio recorder (Part 3)

[2manyrocks]

Tried doing comp recording of 60d and 70d on the 1/8 inputs.  Came out similar since both use njm4580 amps, but 70d was a bit shrill.  The 60d was set on high and the 70d was set on high +.  Came away liking 60d version.

The recording wasn't clipped.  Wonder if the ranges on the 70d are such that I should have set it to high and adjusted the gain Knobs higher? 

[jmerin]

http://www.bhphotovideo.com/find/dealZone.jsp

21.95 ships free


Nice battery for the Tascam 70D

15,000 mah originally 48 dollars, down to 21 shipped.. I grabbed one. I now have two decent battery packs.

[voltronic]

Tried doing comp recording of 60d and 70d on the 1/8 inputs.  Came out similar since both use njm4580 amps, but 70d was a bit shrill.  The 60d was set on high and the 70d was set on high +.  Came away liking 60d version.

The recording wasn't clipped.  Wonder if the ranges on the 70d are such that I should have set it to high and adjusted the gain Knobs higher?

I wonder if the 1/8 inputs were set to MIC instead of LINE?  If set to MIC, then the HIGH+ range would get you up to 38 dB gain on those inputs according to the specs.  They don't specify for the LINE setting.  Either way, I found through my very non-scientific testing that HIGH+ is quite a bit noisier than the other two settings.

If you're using an external preamp, I'm not sure why you would use anything other than the LOW range and LINE setting.  Or were you running PIP mics straight in or battery boxes instead?

[tim in jersey]

Joining the team. Mine should be here on Friday. 

[2manyrocks]

Tried doing comp recording of 60d and 70d on the 1/8 inputs.  Came out similar since both use njm4580 amps, but 70d was a bit shrill.  The 60d was set on high and the 70d was set on high +.  Came away liking 60d version.

The recording wasn't clipped.  Wonder if the ranges on the 70d are such that I should have set it to high and adjusted the gain Knobs higher?

I wonder if the 1/8 inputs were set to MIC instead of LINE?  If set to MIC, then the HIGH+ range would get you up to 38 dB gain on those inputs according to the specs.  They don't specify for the LINE setting.  Either way, I found through my very non-scientific testing that HIGH+ is quite a bit noisier than the other two settings.

If you're using an external preamp, I'm not sure why you would use anything other than the LOW range and LINE setting.  Or were you running PIP mics straight in or battery boxes instead?

I was powering AT853s from a SP battery box.  I need to redo the test on mic/HIGH on the 70d and see if the 60d and 70d aren't nearly indistinguishable on 1/8 in.  Then I need to compare the XLRs.

[voltronic]

Tried doing comp recording of 60d and 70d on the 1/8 inputs.  Came out similar since both use njm4580 amps, but 70d was a bit shrill.  The 60d was set on high and the 70d was set on high +.  Came away liking 60d version.

The recording wasn't clipped.  Wonder if the ranges on the 70d are such that I should have set it to high and adjusted the gain Knobs higher?

I wonder if the 1/8 inputs were set to MIC instead of LINE?  If set to MIC, then the HIGH+ range would get you up to 38 dB gain on those inputs according to the specs.  They don't specify for the LINE setting.  Either way, I found through my very non-scientific testing that HIGH+ is quite a bit noisier than the other two settings.

If you're using an external preamp, I'm not sure why you would use anything other than the LOW range and LINE setting.  Or were you running PIP mics straight in or battery boxes instead?

I was powering AT853s from a SP battery box.  I need to redo the test on mic/HIGH on the 70d and see if the 60d and 70d aren't nearly indistinguishable on 1/8 in.  Then I need to compare the XLRs.

So you're saying the way you tested it was LINE/HIGH+ on the 70D?  I would still expect that to be pretty noisy, and still I would think you'd be better off with LOW or HIGH.  Were your levels on the HIGH setting too low?

[willyp523]

Recently joined the team.  Unit arrived Saturday and I immediately installed the latest firmware.  Attended an event I hadn't planned on recording but took the 70D along to experiment.  Recorded an Americana act (electric, acoustic guitar, fiddle and upright bass) nothing too loud, but certainly amplified.  Seated near the sweet spot, recorder on my lap and using the internal mics...I used the new Mid gain setting with the knobs positioned at 12 o'clock.  Pleased with the levels and somewhat surprised with the internals, not that I'd ever plan on using them.       

[2manyrocks]

Tried doing comp recording of 60d and 70d on the 1/8 inputs.  Came out similar since both use njm4580 amps, but 70d was a bit shrill.  The 60d was set on high and the 70d was set on high +.  Came away liking 60d version.

The recording wasn't clipped.  Wonder if the ranges on the 70d are such that I should have set it to high and adjusted the gain Knobs higher?

I wonder if the 1/8 inputs were set to MIC instead of LINE?  If set to MIC, then the HIGH+ range would get you up to 38 dB gain on those inputs according to the specs.  They don't specify for the LINE setting.  Either way, I found through my very non-scientific testing that HIGH+ is quite a bit noisier than the other two settings.

If you're using an external preamp, I'm not sure why you would use anything other than the LOW range and LINE setting.  Or were you running PIP mics straight in or battery boxes instead?

I was powering AT853s from a SP battery box.  I need to redo the test on mic/HIGH on the 70d and see if the 60d and 70d aren't nearly indistinguishable on 1/8 in.  Then I need to compare the XLRs.

So you're saying the way you tested it was LINE/HIGH+ on the 70D?  I would still expect that to be pretty noisy, and still I would think you'd be better off with LOW or HIGH.  Were your levels on the HIGH setting too low?

The test was set to mic HIGH + setting on the 70d.  I was more concerned with trying to stay at a consistent level between the 60d and the 70d when I should have paid more attention to the which gain setting I used on the 70d and then matched gain. 

So I have redo it because I feel like it's botched.

[jagraham]

Just installed the 1.10 firmware. Hopefully going to give the MID gain level a shot tonight, got a free local show to practice for the big shows in a couple weeks. Even if it's just a little higher levels that would be great. Going to be running Nak CM-300s into the 3-4 inputs.

On a related note, I just received custom cables from GAKables to use with the DR-70D. As was recommended elsewhere, I had them custom ordered to have mirrored wires, so the wires exit "under" the recorder. I'll report back.

[jmerin]

Anyone test the MID setting in the field? I might use it at my next show.

[jagraham]

Anyone test the MID setting in the field? I might use it at my next show.

I'm hoping to tonight. I'll report back if it happens.

Just something I'd like to add. I have a Lowepro Flipside 200 "camera bag" that I've used for taping the last few years. Originally it was just something to use to carry all of my gear but it seems to be a perfect fit for the DR-70D. It has adjustable compartments that I need to play with for a perfect setup. However, I've placed the recorder with the front up in the bag and it's just the right amount of space.

[phil_er_up]

Installed the 1.10 firmware.

Ran a test at home and had levels set to high and pods gain at 10 o'clock and the max level on recorder was -6 DB with my stereo at a certain volume number and a specific song. Then I changed it to mid setting with exactly same volume number on stereo and same song and gain pods still at the same 10 oclock position and the max level was -11 DB. So everything the same stereo volume, song, pods at same position and changing from high to mid setting caused a "-5DB reduction". Not scientific just an observation.

Ran setting of low, mid and high at that same volume with pre-amp/without and running 4 channels. The high setting sounded slightly pushed. Also tried line/mic and line sounds more shrill then mic setting to me. Surprisingly I liked the mid setting the best if you did not have a pre-amp. The mid setting did not sound pushed and sounded more natural and better matched the gain pod levels of the recorder then really low or high and my mics. Low setting sounds very natural with a pre-amp in front of it. The kick drum sounded the most real running low setting with pre-amp. It was a noticeable difference.
 
Above results without pre-amp in low/mid/high and pod gain setting for above song at certain volume:
With low setting had to gain pods all the way up and still did not get above -11 DB as max DB signal for the song.
With mid setting gain at about 12 o'clock to get -6 DB as the max DB signal for the song.
With high setting gain almost turned off or at 9-10 o'clock to get to -6 DB as max DB signal for the song.

Did notice if you have both phantom power on the deck seems a little slower functioning wise. Like you are starting to max out the capability of the unit running 4 channels with both phantom powers on. Not saying it had a problem or skipped a beat - just did not respond as fast.

[voltronic]

I did some testing on the gain ranges both before and after installing the 1.10 firmware.  I had been on the 1.01 firmware previously.

Since I don't own a tone generator with variable output level, I used the headphone output of my audio interface with a 1/8" > 1/4" Y cable into the combo inputs of the 70D.  I set the level of that headphone jack such that when the 70D was set to HIGH+ with the trim pot at maximum, it displayed -3 dB.  As I've already established, the display is not that precise, but good enough for this test.  This was only to find gain ranges, not to test noise or performance.

For the LOW gain range (and subsequently LOW and MID on the 1.10 firmware), I raised the headphone output level in order to more accurately see what was going on in the bottom ranges.

Input was set to MIC to match what TASCAM uses on their spec sheet, and I only tested Channel 1 of the XLR combo jacks.  Format was 24/96 WAV.

While recording, I slowly varied the trim pot position.  Those recordings were then examined in iZotope RX and I recorded the maximum and minimum values of each.  For the 1.01 firmware, I was able to have Tascam's stated maximum trim pot positions as starting points, and then use the difference between my maximum and minimum recorded values to figure out what the minimum gain range was.

For the updated 1.10 firmware, I found through testing that my maximum measured levels at HIGH+ and HIGH were identical to that of the old firmware, as was the minimum measured levels of LOW.  I was able to use those numbers to calculate upper range of LOW, as well as the upper / lower limits of MID.  I rounded off the numbers to the nearest dB.  Clearly this was a non-scientific test, but my numbers were consistent enough through multiple attempts that I feel fairly confident in these results.

Gain Range            1.01 Firmware               1.10 Firmware

HIGH+                            +31 to +63                      +42 to +63

HIGH                              +20 to +51                      +30 to +51

MID                                    N/A                                  0 to +22

LOW                               -21 to +11                       -21 to +7

[2manyrocks]

I redid my AT853>SPBB comparison going 1/8 in to the 60d and 70d, both set on high.  I can't tell a difference on those settings.  However, the high + setting is something I'd avoid if possible.

I tried running the AT853s (resistor modded) directly in without the battery box. The 60d seemed to power them enough for testing.  The 70d had some odd noises on it. So I put the BB into the path and the noise ceased FWIW. 

[voltronic]

I updated the FAQ with the new gain ranges, and made a note that HIGH+ is too noisy for most use.  This didn't change with the firmware update, which isn't surprising.  That may be reason enough to mod this unit with lower noise opamps.  I think the new MID setting is going to be the default go-to range though.