DR-03 record gain question

[Greg Miller]

I've read the manual for the DR-03 and can't find a clear answer to this question.

The DR-03 has three switchable settings for recording gain. "Low" and "High" vaguely set recording sensitivity, and both settings appear to also activate AGC. I'm not interested in those.

The third setting is "Manual" and my question concerns that mode. The instruction manual gives this procedure:

1.) Put the unit in "record standby"
2.) Set the recording gain (using arrow keys on the control panel)
3.) Put the unit into actual "recording" mode.

My question is this: is it possible to change the recording gain while recording is in progress?

(Obviously if I'm watching the level meter, and I see the performance getting louder, I would want to lower the gain to avoid overload. Can I do that?)

If another member has a DR-03 and can answer that question, I would be very grateful.

Thanks in advance!

[Rick Reineke]

I don't have the Tascam, but perusing the manual, it appears that the rec. level can only be adjusted in the "record standby" mode. Some of the Sony minidisc recorders were like that as well as the Marantz 620 PDAR.

[Greg Miller]

That is rather my fear. I recall that "anti-feature" from the old mini-discs.

I didn't see any explicit statement that you can not change gain while recording, and of course their procedure is good practice because one should always set gain before recording.

I guess I'm just hoping that it's possible, even though they didn't mention it.

Hopefully we'll hear from someone who actually owns one. Meanwhile I will start scouring on-line reviews.

Thanks!

[Nicholas de Kock]

Greg I received two DR-03 recorders today. I'm extremely happy with the overall quality of the recorder & yes you can manually adjust the recording volume while the unit is recording. I was going to buy two Zoom H1's however the DR-03 is now $60 and a lot more compact than the H1. The menu system works great and on-board mic's sound ok for the price, my lav mic's also work without any problems.

[Greg Miller]

@Nicholas

Thanks for that information. That is indeed good news. (Of course pressing menu buttons will be a bit noisier than turning the rotary pot on the DR-07, but at least it will be adjustable, in a worst-case situation.)

Time to place an order...

[Greg Miller]

I just received a DR-03, so I'll use this space from time to time to post miscellaneous comments.

1.) It's very small and light. You have to see it to believe it. It would easily fit an inside jacket pocket, or a shirt pocket. Think "body mic" for weddings, etc.

2.) Confirming Nicholas, above, the recording gain can be changed manually while recording, although the manual doesn't say so.

However, I notice a slight click in the audio file, each time the gain is changed by one numeric step. If I start recording with gain set at 20, and then hold the "left arrow" button to lower gain to 15, I will hear five clicks on the recorded file: one when the gain display changes from "20" to "19," another when the display changes from "19" to "18," etc. (This is in addition to the recording of the mechanical button "click" if using the integral mics.) Also, gain doesn't change quickly... about two steps per second. So it is important to set gain correctly before you start recording, and change it only in case of a real emergency.

3.) Like every pocket-size recorder I've tried, the DR-03 is very sensitive to handling noise. No surprise, given the low mass, thin plastic case.

4.) In addition to manual record gain, there are two fixed-gain settings ("Low" and "High"). Using the integral mics, even the "Low" setting seems quite sensitive. It seems to have some sort of AGC which seems fine, at least for voice work. It's very difficult to overload the track, yet it doesn't seem to pump very much.

5.) The integral mics appear to be angled apart by slightly more than 90 degrees. You might think, "Great, this is a 120 degree cardioid pair." You'd be wrong. The mics are definitely omni and spaced about 1" apart. As you might guess, the stereo image is nil when played back on loudspeakers. Even on an HD-280, there is no discernable stereo image... not nearly as good as omnis spaced 8" or so (pseudo- or actual binaural). IMHO, they might as well have one integral mic.

Conclusions after < 1hr.:

• A good pocket-size recorder for voice work, if you add a good external tie mic.
• Probably also fine for stereo recording, with a good external mic. (But a bigger recorder might have more features or better controls.)
• The integral omni mics are useless for any application requiring stereo.
• If you want a single piece of hardware for "quickie" stereo work (e.g. when you come across an interesting street band, or whatever) the DR-03 is not the answer.

I'll try to be a little more scientific tomorrow. Meanwhile, I need to assume the horizontal.

[Nicholas de Kock]

Greg good report. I bought the DR-03 specifically for it's small size for recording audio at weddings. I also bought two Giant Squid Lav (tie) mic's with a right angled plug & 2-feet of cabling just enough to go from the groom's pocket to recorder. I haven't had the opportunity to test it yet so I'm not comfortable using them at a wedding however if my experiment works well I would like to replace my wireless mic's with external recorders.

I'm still torn between using AGC or manual volume control. I've noticed quite a bit of hiss when using AGC in quiet moments however since the recorder won't be monitored and in the grooms pocket I'm also afraid to use manual, I'll have to test for optimal volume settings.

I like the idea of the timer which allows me to set the DR-03 to start recording at a specific time eg. before the ceremony starts so I don't have to worry about pressing the record button.

[Greg Miller]

Originally Posted by Nicholas de Kock

since the recorder won't be monitored and in the grooms pocket I'm also afraid to use manual, I'll have to test for optimal volume settings.

I would test it a lot, and listen to how the AGC behaves. It might be fairly benign. It will depend on the "sensitivity" setting, and that machine seems to be pretty "hot" so I think you'll want low sensitivity. I hope to play with mine later today, and I'll post anything that seems conclusive or relevant.

If one knows the source impedance of the mic, and the actual input impedance of the recorder, one can devise a resistive pad (using two or three 1/8-watt resistors) that will allow you to record a mono mic at different level on the two channels. You would then normally transfer from the louder channel, but in the rare event that it overloads, you could transfer from the lower channel for a few milliseconds until the overload has passed. Of course this is just a few more connectors and more bulk to put in the groom's pocket... is it worth it???

Originally Posted by Nicholas de Kock

I like the idea of the timer which allows me to set the DR-03 to start recording at a specific time eg. before the ceremony starts so I don't have to worry about pressing the record button.

And you also miss recording those few awkward moments when the groom stops in the loo before the ceremony.

[Nicholas de Kock]

I've tested the Tascam DR-03 at three separate occasions over this weekend, the AGC is definitely a bit hot & distorts quite a bit. I gave the unit to a church to test for me, we set one unit on Low AGC with a lav/tie mic on the presenter, the distortion on AGC is rather disappointing a better limiter or slightly less sensitive gain would have been nice. I had my second unit connect to the house mixer on LINE and set the recording level on manual at 10 this came out very clean except for the hiss on the system mixer.

Disclaimer: I reduced the bass levels on the attached sample. The purpose of this test is purely to test the effectiveness of the AGC. Recorded at 48/16bit.

[Greg Miller]

Thanks for posting that file. There is definitely some distortion in both versions.

The recording of mic -> DR-03, using internal AGC, certainly is the worse of the two. I am curious whether the recorder was near 100% on the original file, and I can't tell that since you removed some LF energy from the file.

I suspect that presenter is rather loud, because at the words "over" and "bored" through your house PA system sound rather marginal. I doubt that he's actually making the mics distort, but I'll bet he's generating some significant voltage.

Would you care to post another version of both files, with no equalization or level change?

I've read the manual and I've navigated the menus, and I'm disappointed that there's no way to implement any AGC or peak limiting when in the manual recording mode. If you want AGC, you're stuck with one of their two fixed gain settings, both of which are too "hot" IMHO. If you want manual gain adjust, you have no AGC or peak limiting to fall back on.

Assuming that the recorder's mic pre is distorting (we can't tell for certain, unless we see a file with no gain or EQ changes), how would the recorder perform with a different input? I wonder what would happen if you used the same external mic, and a battery box, feeding into the recorder's Line Input.

Or, if I know the source impedance of the mic, and the input impedance of the recorder, I can design a pad using one or two 1/8-watt resistors, which will allow you to record an external mic at a lower level on the second channel. This would give you some emergency headroom in case your gain was set too high.

I guess I'll have to perform a few tests to ascertain the actual input impedance (and also check the "Plug-in Power" voltage).

[Greg Miller]

I just ran some quick tests on the DR-03, and for comparison on the DR-07.

First, I checked the open circuit "Plug in power" voltage (no mic connected to the jack).

Next, I sequentially connected three different resistors (15k ohm, 4k7 ohm, 3k3 ohm) to the input. This created a voltage divider with the internal supply resistor as the top leg, and my external resistor as the bottom leg. I measured the voltage in each case. Then, simply using Ohm's law, I calculated the theoretical value of the internal resistor in each of the three cases (the results were slightly different with each test resistor). Finally, I averaged the three values for a given recorder; that is the "approximate" value of the internal series resistor which feeds "Plug in power" to the external mic.

Model   V(open) R(series)
DR-03     2.4   2k8 ohms
DR-07     2.4   4k2 ohms

I'm powering each recorder with two NiMH Eneloops, so the supply voltage is 2.4V. Thus it appears that the recorder's power supply voltage is fed to the mic jack without any intermediate voltage reduction.

It also appears that the DR-03 is capable of providing more current (mA) to a given mic, since the series resistor appears to be significantly lower in value.

In any event, the voltage provided to the mic is on the low side. Some commonly used mics supposedly require a higher supply voltage than this; a voltage this low might result in distortion and/or reduced headroom.

(I would check my Microtrack for comparison, but, as usual, the $%#&*#@ non-replaceable proprietary internal battery is dead. A pox upon the designer of Microtrack.)

--

Nicholas: can you tell us what mic you used directly with the DR-03 in the test you posted? And can you check the specs for that mic, to be sure it will work correctly with a supply voltage this low? Perhaps that is part of the distortion problem.

--------------- UPDATE ---------------

I just talked with Chris Carfagno at Sound Professionals. He says that all the mics they manufacture will work down to about 2 volts; however, at that level they will start to distort above about 105 dB SPL.

Of course other mics will be different. I have read posts from a different manufacturer who states that more voltage is needed for their mics.

And it remains to be seen how much voltage the DR-03 can handle on the mic input, before the preamp distorts. As always, many variables, few specs. But that's to be expected with a $60 recorder that is, actually, just a "really nice" toy.

Perhaps others will want to chime in with information about which specific mics will, and will not, work at this low a voltage (and what SPLs they can handle).