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

[voltronic]

Just tested with the FP24 going into the EXT 1/2 input of the 70D.  On the screen of the 70D, the dB level starts at -23dB (at LOW) gain and then increases in 2dB steps.  Looking at the resulting file on the computer shows that in reality it is increasing in 0.5dB steps starting at -23.5dB.

The bad news: My channels were probably not as matched as I thought they were, because the readout on the 70D is not accurate.  The poor monitoring is now my #1 biggest problem that needs to be fixed.

The good news: 0.5dB steps is nice to have.

EDIT: I updated the FAQ page with this as Issue #1, and also sent a PM to Tom Duffy, our TS Tascam rep.  As I said before, I haven't ever gotten a response from him so maybe I'll send the issues list to Tascam customer support directly.

[voltronic]

I'm considering getting my 70D modded, but I want to get an idea of at least the self-noise of the stock unit.  So, I did a quick test today, the best I could without any actual test equipment.  If anyone with a modded unit would be willing to try the same test, I'd be curious to see the results.

All 4 channels recording at 24/48 BWAV, which is my normal recording format.  Input set to MIC, but nothing connected so I would be recording silence / noise.  Running off internal AAs.

I first recorded 3 sets of files (LOW, HIGH, and HIGH+ ranges) with the gain knobs at max for the worst-case scenario.  I ran the resulting files through the Dynamic Range Meter plugin in Foobar to get the Peak and RMS values.

DR         Peak         RMS     Duration Track
--------------------------------------------------------------------------------
DR7      -78.30 dB   -85.82 dB      0:11 ?-01_LOW_MAX_150525_0016S12
DR7      -77.85 dB   -85.97 dB      0:11 ?-01_LOW_MAX_150525_0016S34
DR10     -52.69 dB   -64.63 dB      0:11 ?-02_HIGH_MAX_150525_0017S12
DR11     -53.17 dB   -64.47 dB      0:11 ?-02_HIGH_MAX_150525_0017S34
DR10     -40.91 dB   -52.64 dB      0:11 ?-03_HIGH+_MAX_150525_0018S12
DR10     -41.11 dB   -52.51 dB      0:11 ?-03_HIGH+_MAX_150525_0018S34
--------------------------------------------------------------------------------

Next I did the same thing, with the knobs at zero:

DR         Peak         RMS     Duration Track
--------------------------------------------------------------------------------
DR6      -80.13 dB   -86.43 dB      0:11 ?-01_LOW_MIN_150525_0021S12
DR6      -80.25 dB   -86.56 dB      0:11 ?-01_LOW_MIN_150525_0021S34
DR6      -80.38 dB   -86.43 dB      0:11 ?-02_HIGH_MIN_150525_0020S12
DR6      -80.38 dB   -86.56 dB      0:11 ?-02_HIGH_MIN_150525_0020S34
DR9      -74.87 dB   -84.26 dB      0:11 ?-03_HIGH+_MIN_150525_0019S12
DR9      -75.58 dB   -84.44 dB      0:11 ?-03_HIGH+_MIN_150525_0019S34
--------------------------------------------------------------------------------

I verified these numbers visually watching the meters in iZotope RX, and I took screenshots of the Channel 1/2 files which are below.  (Channel 3/4 files essentially looked the same, and you can see from the numbers above they are within 0.5dB of the other two channels.)

[Mike D (VT)]

Thanks for all the info within threads 2 & 3; I have been researching a 4 channel upgrade from my Fostex fr-2LE, and mostly looking at an R-44. The DR-70 wasn't really on my radar because it didn't seem like a serious contender (I thought of it as a 'dumbed down'  photo-centric recorder). Although from what everyone is saying the recorder is a legit pro-level unit (correct?). Is the DR-70 comparable to the likes of a R-44 (or others)? Please forgive me if these questions have been answered before.
Cheese Cadet - You had yours modded by Jim Williams, but he doesn't offer this anymore? Was that a one-off?
Busman does do a mod to the preamps? What is the cost?
Any other summaries are appreciated.

[Cheesecadet]

Thanks for all the info within threads 2 & 3; I have been researching a 4 channel upgrade from my Fostex fr-2LE, and mostly looking at an R-44. The DR-70 wasn't really on my radar because it didn't seem like a serious contender (I thought of it as a 'dumbed down'  photo-centric recorder). Although from what everyone is saying the recorder is a legit pro-level unit (correct?). Is the DR-70 comparable to the likes of a R-44 (or others)? Please forgive me if these questions have been answered before.
Cheese Cadet - You had yours modded by Jim Williams, but he doesn't offer this anymore? Was that a one-off?
Busman does do a mod to the preamps? What is the cost?
Any other summaries are appreciated.

Jim gave me his detailed instructions on the mod and I had a local engineering from do the mod based on this detailed instruction.  Jim is not doing any mods currently.

[Mike D (VT)]

Thanks for all the info within threads 2 & 3; I have been researching a 4 channel upgrade from my Fostex fr-2LE, and mostly looking at an R-44. The DR-70 wasn't really on my radar because it didn't seem like a serious contender (I thought of it as a 'dumbed down'  photo-centric recorder). Although from what everyone is saying the recorder is a legit pro-level unit (correct?). Is the DR-70 comparable to the likes of a R-44 (or others)? Please forgive me if these questions have been answered before.
Cheese Cadet - You had yours modded by Jim Williams, but he doesn't offer this anymore? Was that a one-off?
Busman does do a mod to the preamps? What is the cost?
Any other summaries are appreciated.

Jim gave me his detailed instructions on the mod and I had a local engineering from do the mod based on this detailed instruction.  Jim is not doing any mods currently.

So will your guy do this mod for others? It sounds like you're happy with it. What did it cost? PM if you want.

[MakersMarc]

So what's the consensus on build quality? The features are great and the quirks can be worked around, but this looks like a playskool version of a fr2-LE....is it really that cheap feeling? The price is right, but I don't want to drop even 500 on a modded unit and have it start to fall apart, can it live in a gear bag getting bounced around a bit?

[2manyrocks]

It doesn't feel or look cheap.  I don't think the outer case is metal because a magnet won't stick to it, but the 70d has a solid feel to it.  Given it's small size, why bounce it in a gear bag at all when it's small enough to fit in a padded equipment case?  mcmelectronics.com has several pelican type plastic cases with foam inserts for under $30 that should fit the 70d and hold a couple of microphones, too. 

Whether the unit needs or really benefits from the mod is still a bit of a subjective question.  Other than Voltronic's recent post and a post in the first thread comparing the 70d with a SD unit, there doesn't seem to be any other direct measurements of the noise floor of the factory 70d, and so far, there have been no posts of measurements of any modded 70d versus the factory 70d. 

[MakersMarc]

Thanks.

Forgive me if this was already posted, but Chris is offering a new unit with all the freebies, with modded analog input channels and headphone amp for 430 shipped.

[Ozpeter]

Input set to MIC, but nothing connected so I would be recording silence / noise.  Running off internal AA

I think such measurements would be suspect without a 150 ohm plug being used in the mic input socket.

See http://www.rane.com/note145.html - the section headed "EIN. Equivalent Input Noise or Input Referred Noise"

[voltronic]

Input set to MIC, but nothing connected so I would be recording silence / noise.  Running off internal AA

I think such measurements would be suspect without a 150 ohm plug being used in the mic input socket.

See http://www.rane.com/note145.html - the section headed "EIN. Equivalent Input Noise or Input Referred Noise"

As I said, I do not have the proper equipment or knowledge to do real measurements.  I wish someone with the means would do so - it's surprising to me that of all the published reviews of this unit, not one has a set of measurements.

[Life In Rewind]

Is anyone else feeling like the LOW + MIC gain setting is REALLY LOW...?

Both my Sony ECM999PR and Altec 626As - I can run the knobs all the way up - and still wish for more (both of these behave NAK300-like with regard to output, and are battery powered)

So - I've found myself switching to HIGH - risky though - because at minimum gain position - it turns the signal off. (The biggest flaw I've discovered in recorder - this needs to be fixed!)

With my Audix mics - LOW + MIC/phantom - levels are more what I would expect - but even then - not uncommon to be past 2'oclock.

It would be a cool feature to be able make the bottom gain/sensitivity setting a user preset.

[2manyrocks]

Input set to MIC, but nothing connected so I would be recording silence / noise.  Running off internal AA

I think such measurements would be suspect without a 150 ohm plug being used in the mic input socket.

See http://www.rane.com/note145.html - the section headed "EIN. Equivalent Input Noise or Input Referred Noise"

"to run all the tests...$10,000 of equipment...." in 2003 prices. 

Wonder how much of a test one could run with the Behringer cable checker that has a built in tone generator?

And yes, Low doesn't seem to do much for me.

[noahbickart]

Is anyone else feeling like the LOW + MIC gain setting is REALLY LOW...?

Yes, with schoeps mk41v> Naiant PFA, I had to run the gain knobs all the way up to get levels to peak between 12 and 6 at TTB last week. Now the PA was relatively low, but nonetheless. i think at louder rock shows indoors low should be fine, but anything acoustic or quiet run it at "high."

[stevetoney]

Check Beans recent recording out...it's made with DR70D with the stock unmodded preamps.  Sounds outstanding to me. 

https://archive.org/details/aqueous2015-05-15.mk4.pfa.70d.flac24

You can comp this recording against two others that were made from the same location.  I've linked them below.  The others have very similar setups, with the main difference being high end preamps in the chain.  Bean ran a pair of MK41 through a VMS02IB into the other two channels of his DR70D.  I ran my vintage Schoeps through a PSP3 into my Sony D100.  My files were recorded in DSD format and converted to 24/48.  The bottom line is that the internal preamps on the DR70D hold up really REALLY well in this comp IMO.

https://archive.org/details/aqueous2015-05-15.mk41.vms02ib.70d.flac24
https://archive.org/details/aqueous2015-05-15.m934b_24bit

Finally, Aqueous was one of the two backup bands that night.  The headliner was Tauk, so the same comp can be heard with another bands music.   

https://archive.org/details/tauk2015-05-15.mk4.pfa.flac24
https://archive.org/details/tauk2015-05-15.mk41.vms02ib.70d.flac24
https://archive.org/details/tauk2015-05-15.m934b_24bit

[jbell]

MK4>DR70d sounds really good!!  Thanks for the link.