Topic: TASCAM DR-2D Dual mode questions

[red]

Mr.Scully - I had recently wondered about running w/o b-box, here's the thread (concurrence is use b-box for best results):  http://taperssection.com/index.php?topic=166275.msg2076621#msg2076621

[Gutbucket]

Can you confirm that your battery box battery wasn't run down?

Assuming it was working correctly, it sounds like you'll need a preamp instead of the battery box to increase the microphone output to line-level as well as providing power to the microphones when using the Line-In.

Lacking that, you can try using your most sensitive pair of microphones through the battery box into the Line-Input, assuming one of the other pairs is more sensitive than your CA-14s.

[danny3]

Circumstance has had me running small mics (CA-14 or AT933) without battery box/preamp into my DR-2d (PIP on.) Dependent on the loudness of the music, I would raise the side input level (up to 100) or try the input setting at MED.
Best practice would certainly be to use a battery box or preamp. 

[Gutbucket]

The issue he's having is getting enough level into the line input, not the mic input.

[danny3]

oops, I should have  digested the question a bit more, sorry ...


edit to add: I guess I was addressing the second part of his question...
(from Mr. Scully) "So my questions are:
1. What should I do to record from line-in at a normal volume?
2. The mic recording without battery box sounds good. Should I actually use a battery box? (With hidden taping it's more difficult to smuggle in more gear past the security). Or is it sufficient to set "power on" in the Tascam settings instead?"

[Mr.Scully]

Yes, it's the line-in input I'm having troubles with. The mic input works fine (I switched the input gain from low to mid and the levels are quite good now with input level around 80-90).

I don't think it's a battery box problem (I don't have a spare battery to replace it in the CA battery box). I tested also my SoundProfessionals battery box and mics and although the resulting level is about twice as high as with CA-14, it's still very low.

This is the resulting WAV file opened in Goldwave (line-in input = 100). First half recorded with CA-14 and CA battery box, second half with SP-CMC-9 and SP battery box.
http://www.queenconcerts.com/tmp/goldwave_tascam_linein.jpg

You can see I'd have to change the volume to about 1500% to actually hear anything. When I record, the Tascam recorder says the input level is "-43 dB". WIth SP-CMC-9 the input level is about "-30 dB".

I must have overlooked something. I'm not buying a preamp, I've been recording loud rock gigs for years (with minidisc recorder or Edirol R-09 HR) and never had any problems with volume with any other recorder, in fact it's vice versa and I usually have to keep the input level low. I must have overlooked some setting on my Tascam, that's the only explanation I can come with. It's not just the dual mode, the result is the same when I record just line-in.

If I record a gig in this "silent" mode and then amplify it in sound editor, I will get some additional hiss and the overall sound quality will get worse, right?

[Gutbucket]

Levels shoudn't differ through the two different battery boxes unless the CA has a filter, built-in attenuation, or a nearly dead battery.  I suspect the battery.  If you have a voltmeter, check voltage across the terminals with the battery in the circuit powering the microphones.  If its less than about 8V then replace the battery.  You must measure it in the curcuit under load, not alone by itself in isolation.

If the level of the music wasn't high enough in comparison to the analog noise floor when the recording was made, the noise will become audible when you increase signal levels in a sound editor.  You are amplifing the noise along with the music.  That amplification of the noise floor will be the primary factor detracting from the sound quality.

I use the CA-UGLY preamp, about same size as a CA battery box. You might consider one for use with your line-input.  Because the microphones I use are considerably more sensitive and output a much higher signal level for a given SPL, much of the time I have it set to around zero gain, and the UGLY is acting simply as a battery box and line-stage buffer rather than as a preamp increasing signal gain.  But it gives me the option of increasing gain if I need to, and allows for adjusting the left/right channel gain balance if the microphone sensitivites of the pair are slightly off.

[Mr.Scully]

OK, it's not the batteries. The Tascam DR-2D inputs are for some reason much more "weaker" than Edirol R-09 HR inputs. I bought new batteries and did a test yesterday at a big indoor concert of a local (Czech) rock band (16000 people in the audience). I had three sets of mics on my T-shirt (luckily there was minimum security and even the metal detectors at the entrance didn't work properly).

1. CA-14 cardioids + CA battery box => line-in of my Edirol R-09 HR (volume level 70%)
2. SP-CMC-9 cardioids + SP battery box => line-in of my Tascam DR-2D in dual mode (volume level 100%)
3. Sony ECM-719 mic (power on) => mic input of my Tascam DR-2D in dual mode (volume level 70%, mid sensitivity).

Results in terms of volume levels: the Tascam line-in input is (even at the 100% level!) about five times lower than the Edirol line-in input at 70% level. (And the SP mics are actually more sensitive than the CA ones!). So the difference is really huge. With Edirol I can change the settings whichever way I want (depending on the venue) while with Tascam I always have to set it at 100% and even then I have to amplify the result in sound editor by about 1000%!

Results in terms of sound quality: my oldest mic (Sony ECM-719 for only about $100) would be the winner, it sounds so fresh and dynamic! CA-14 would be the second one (good clarity and bass but worse overall dynamic range), SP mics were the most expensive and sounded slightly worse (but that could partially be caused by the low input sensitivity - the need for major amplifying may have affected the overall quality). But the quality differences between them were minor, probably not more than 10%.

[danny3]

Maybe try switching your DR-2d inputs; seems like the ECM-719 might have a hotter signal and the SP-CMC-9s might need gain from the recorder?
Or use a preamp with your line input mics.

[Gutbucket]

Sounds like you need a preamp to provide some gain ahead of the DR2d line-input rather than a simply a battery box for that input.

[Mr.Scully]

Yes, it's obvious a preamp is needed in this case but I just wonder why. Both my mics with the battery boxes (ChurchAudio and SoundProfessionals) provide a much lower signal to the Tascam recorder than to Edirol. So either it's normal and there are huge differences between the individual audio recorders - or there's something wrong with my Tascam.

No big deal, I'm always taping loud rock gigs so I think even amplifying my recordings in sound editors does not increase the hiss level (or at least it's not audible).

[Gutbucket]

It's normal differences between the recorders.

The Tascam line-input is designed only for a line-level signal.  You are sending it a lower microphone-level signal.

The Edirol line-input is also designed for a line-level signal, but provides additional gain control over that input, which allows for amplifying an input which isn't really line-level.