Trouble with recording phone interview using TASCAM DR40

[DaveR514]

My wife has a project where she hopes to use her newly purchased TASCAM DR-40 for a project that will involve recording some phone calls / interviews, and we’ve run into an infuriating problem that I’ve been trying to figure out.

I’m playing the role of bumbling newbie engineer, and after reading through the manual poking around the internet trying to find the answer for myself, I realize that I’m stuck and hope someone can point us in the right direction.

To record her side of the conversations, we have a Shure SM58 dynamic microphone (so with a male XLR jack) that we’ve plugged into one of two XLR/TRS combo jacks on the bottom of the unit.

To record the other party, we are using a 3.5mm male-to-male TRS audio cable which is plugged into the mobile phone’s 3.5mm jack. The other end of this cable is plugged into a 3.5 mm TRS to 1/4 inch TRS adapter, which is itself plugged into the other XLR/TRS combo jack on the bottom of the unit.

The other party will hear my wife thru the phone as if on hands-free (though I'll buy a mic/headphone splitter, and feed a split of the recorder's aux out back into the phone in the future).

We are not using TASCAM’s built-in mics for these interviews.

On the REC MODE screen, we have tried multiple settings and have settled on STEREO, DUAL, with the source set to EXT IN 1/2. The secondary (DUAL) recording is set at -10 dB, and could be used as a backup.

The EXT IN switch on the side of the unit is set to MIC.

The input level is adjusted with the toggle button on the side of the unit to where speaking into the external SM58 mic has the level meter dancing around the little triangle mark without triggering the PEAK indicator light.

With my Samsung phone plugged in to the recorder as described above, and using a chatty podcast as the source, and adjusting the volume on the phone to about max closely matches the levels from the external mic.

I’m not sure that this is the right way to go about things, but in the MIXER settings I have one source paned all the way to the left, and the other paned all the way to the right (which my gut tells me will be easier to work with, and can all be centered later).

Placing a test phone call with everything set up in this way results in a recording that can be dropped into Audacity, and sounds great.

Everything goes wrong when we instead plug my wife’s Pixel phone into the recorder as described above – the sound coming out is so low as to be barely discernible, and the volume on the phone can not be turned up enough to make a difference.

Another test, with my daughter’s hand-me-down Motorola phone is blown-out loud and distorted.

The only phone that yields in a workable recording is mine, but I need my phone and so need to figure out how to make it work with hers…

My guess is that ideally, the recording from one source would be "line level" and the other would be “mic level”, but that doesn’t seem to be possible with the TASCAM DR-40. I also doesn’t make sense to me why one phone would be way too loud, another way too low, and a third just right – surely all the phones have comparable levels out of their 3.5 mm jacks…

I apologize if this has been addressed elsewhere, but I can’t find it if it is.

Any suggestions would be greatly appreciated.

 

[Art Anderson]

It's a "thumbs up" that you even got a usable signal from a phone's headphone signal that will work with the same input settings as needed for the SM-58. But you do say only the Samsung phone seems to be working acceptably.

Without me trying to look up the connections of a Samsung phone - vs Pixel (4 conductor TRRS assumed), the DR-40 settings should probably be different. Assuming the DR-40 firmware is current, go into the REC MODE. You write that you are using STEREO. Change that to DUAL. That records 2 tracks that are separate entities, not stereo. I find them easier to edit independently.
Then on the second row, put SOURCE to EXT INDEP. This wasn't available on the earlier releases and it's a very good thing to have. With EXT INDEP you can adjust the recording input levels of XLR jacks independently. I use that all the time if I'm recording with two completely different microphones positioned as anything but stereo, eg. one at head height for the singer and one down lower for their guitar.

You'll still have your Dual safety track functioning as you'll see that setting on the next row.

Back out of the settings menu. Put the DR-40 in standby Recording (flashing red).
With your two trial audio sources doing their thing, press 1/2 SOLO (above the HOME button)
Look at the very bottom of the display and see EXT Lch LVL and a bar. You adjust the input sensitivity with the Level Input buttons on the left of the case. Tap the 1/2 SOLO a second time and again use the Level Input buttons to adjust level on the EXT Rch LVL graph.
It took me some practice because you can't doddle. The function times out very quickly and you have to start over. Prepare by having a finger over those buttons on the side of the case before you tap 1/2 SOLO and keep it there, ready to adjust the Rch.

In the manual, this topic is under Recording / Adjusting the Input Level / Independent L/R channel EXT, etc.

I don't see any need to be using the DR-40's Mixer function if you are bringing the files into Audacity. I use Audacity all the time for my DR-40, DR-70, etc. etc. with this method.

This still leaves the phone levels and noise but maybe all you have to be doing is handling the input levels independently to get what you're after > no distortion.

 

[tzdvl]

I think I can shed a little light on your problem.

The DR-40 input requires a TRS (or XLR) type connector, but the signal for each channel MUST be a balanced (hot-cold-ground) MONO signal. The Shure mic is correct, but the phones are not...

I don't know of ANY phone that outputs a balanced mono signal from its output jack.
You are confusing a STEREO headphone TRS output with a balanced MONO TRS output.

The phones’ output is two single-ended, unbalanced signals, one (left) to the tip of your cable, and one (right) to the ring.

The DR-40 will not work with ANY single-ended unbalanced input signal. See this thread:
https://www.tascamforums.com/threads/dr40-help.7330/

I don't know the exact kind of output connections on the three different phones you're using, but I know different phones use different standards. My iPhone has a four-section TRRS connector, to allow connection of stereo headphones PLUS either a microphone or video. Some phones have a TRRS connector arranged (from the tip) left, right, ground, mic, and others use a different order, left, right, mic, ground.

See here, especially the sections "Camcorders and Video Breakout Leads" and "Mixing Plugs and Sockets":
https://www.cablechick.com.au/blog/understanding-trrs-and-audio-jacks/

When you connect a left, right, ground stereo TRS signal to the DR-40 you're most likely to hear a very low-level signal that consists of only the difference between the left and right stereo channels.

It sounds like the three phones are making three different connections using the TRS cable, so the three phones are behaving differently.

I agree with Art, that you are lucky to have gotten a usable signal from any of the phones.

 

[Geoffrey Kolbe]

Well, "The DR-40 will not work with ANY single-ended unbalanced input signal." is a little strong. As was explained in that thread, the input from a single-ended unbalanced input signal will be down 6db on a balanced input, so you need more signal to get a decent input.

I am managing very well with a lav radio mic with a single ended output that plugs straight into the DR40. But I had to make a pre-amp for the mic to get a decent signal...

 

[tzdvl]

I guess I should have written that the DR-40 is not designed nor intended to work with unbalanced single-ended sources.

It will work with an unbalanced +/ground input, but only if the signal is strong enough (or boosted with a preamp). The -6dB level reduction (half as loud) is because the whole negative (“cold”) side of the differential input amplifier is being bypassed.

I think that’s why DaveR514 was able to make a useable recording using his Samsung phone. The layout/arrangement of the output jack contacts on his phone must connect to the TRS cable in a way that feeds a good +/ground mono signal to the recorder, and his phone has a strong enough output to overcome the -6dB penalty.
That would happen if the cable connects to the signal from just the L or R (or both) contacts, and ground.

Depending how a phone’s output jack contacts connect to the TRS cable, the most likely alternative connection is to treat the L, R, ground as if it was a true balanced signal. The L output is fed to the “hot” input, the R is fed to the “cold” input, and ground to ground. In that case the L and R signals are cancelled out by the input amp, and the DR-40 records only the difference between L and R. That would be noise only for a mono track, or only the “difference” signal for a stereo track. Either would be very quiet and unusable. I think that’s what’s happening with the Pixel phone.

 

[tzdvl]

I think what I would try with the Pixel phone is to go “all in”, and hope the phone has enough output to overcome the -6 dB level reduction...

I would connect the TRS cable to the phone, and use a mini TRS stereo to 1/4-inch MONO adapter to connect to the DR-40 input.

Use an adapter like this one:
https://www.sweetwater.com/store/de...ini-stereo-to-mono-1-4-inch-headphone-adapter

The adapter should short together the L (tip) and R (first ring) to ensure a good mono signal between L+R and ground.

Then you cross your fingers and hope the phone’s output is strong and clean enough to make a good recording. If so, you should be able to tweak the levels between the Pixel phone and the Shure mic by adjusting the volume level on the phone.

It’s worth a shot, for the price of the mini stereo to 1/4 inch mono adapter!

Good luck!

 

[BazzBass]

buy a little 3 channel mixer.
Plug the sm58 into channel 1. Plug the phone into channels 2 and 3 as a stereo pair,using a trs to 2x ts adaptor. Take the stereo outs from the mixer into the two external xlr inputs on the DR40.the mixer will boost the gain to make up for the -6db loss. trust me.

 

[DaveR514]

Art Anderson -- I had not thought to make sure that the firmware is up to date. I guess I wasn't as clear as I should have been, in that the REC MODE is set to DUAL. Currently have the EXT IN set to EXT IN 1/2, and so will try EXT INDEP. as you suggest. Thank you for the super clear instructions!

tzdvl -- I was indeed been confusing a STEREO headphone TRS output with a balanced MONO TRS output. We did pop into our friendly local electronics bit and bops store, but they unfortunately did not have a 3.5mm stereo to 1/4" mono adaptor. Along the way, I've picked-up a Rode VXLR Mini-Jack Female to XLR Male Adapter -- haven't had a chance to try it yet, but wondering if it might do the same trick. If not, I might need to test some combinations and splice some wires together to make my own stereo to mono wire.

Geoffrey Kolbe -- Hmm... Maybe I need a pre-amp...

BazzBass -- All we wanted to do was to record some phone interviews as clearly as possible, and I was hoping the DR-40, an XLR mic and a 3.5mm stereo to 1/4" wire was all we'd need... Now I'm looking at a XENYX 502 5-Input 2-Bus Mixer and wondering it it's the missing piece.

Again, I'm very grateful for all of your help. It's nice feeling like there are some folks out there who know (muhc) more than I and who are willing to take a few minutes to straiten me out. Cheers!

 

[DaveR514]

I already have a 3.5 mm TRRS headphones/microphone splitters, and am guessing (hoping) that it splits TRRS to two TRS... Am now wondering if I can plug one into the phone, then plug a 3.5 mm TRS to 1/4" TS cable (Like this: https://www.amazon.com/TISINO-3-5mm-Stereo-Interconnect-Cable/dp/B084X6X7ZL) into the headphone part of the splitter, and plug the TS end into one of the TASCAN DR-40's XLR/TRS jacks...

OR, maybe just buy that XENYX 502 some guy is selling the next town over...

 

[tzdvl]

The Amazon TISINO cable is exactly the stereo to mono adapter you need. I would try it with the microphone splitter, and also just the cable plugged directly into the phone.

Anything is worth a shot! Hope it works!

 

[BazzBass]

buy the mixer anyway,it makes things so much easier. Like adjusting the input volumes of the two sources with two knobs, panning them to suit, THEN boosting the signal in to the DR40 for optimal recording volume . Mine was $80 AU so about $50US

 

[DaveR514]

Hi All -- just wanted to let you know that I did come up with a set-up that worked, and wanted to thank you all again for the help understanding the not-so-obvious subtleties.

For the record -- and the benefit of anyone else who might be struggling to figure out how to record phone interviews on two tracks using a TASCAM DR-40 -- here is how I did it:

(1) Plug a 3.5 mm TRRS “Y” splitter – male, to headphone (female) and microphone (female) -- into the phone's 3.5 mm headphone jack.

(2) Plug one end of a 3.5 mm TRS (male to male) cable into the 3.5 mm headphone jack on this TRRS “Y” splitter connected to the phone.

(3) Plug the other end of this 3.5 mm TRS (male to male) cable into a 3.5 mm TRS (female) TO XLR (male) Adapter [I used a “Rode VXLR Mini-Jack Female to XLR Male Adapter for VideoMic”].

(4) Plug this 3.5 mm TRS (female) TO XLR (male) Adapter into one of the two XLR/TRS combo jacks on the bottom of the TASCAM DR-40 [this gets the audio from 2nd party to the phone call into the recorder].

(5) Plug a dynamic microphone with a (male) XLR jack into the other XLR/TRS combo jacks on the bottom of the TASCAM DR-40 [this gets the audio from 1st party to the phone call into the recorder].

(6) Plug a 3.5 mm TRS “Y” splitter – male to 2 female -- into the 3.5 mm headphone / line out jack on the side of the TASCAM DR-40.

(7) Plug best available quality headphones into one of the two female jacks on the TRS “Y” splitter plugged into the side of the TASCAM DR-40 [this allows for live monitoring of all audio of the phone call being recorded].

(8) Plug one end of a second 3.5 mm TRS (male to male) cable into one the second of the two 3.5 mm jacks on the TRS “Y” splitter plugged into the side of the TASCAM DR-40.

(9) Plug the other end of this second 3.5 mm TRS (male to male) cable into the 3.5 mm microphone jack on the TRRS “Y” splitter connected to the phone [this allows the 2nd party to hear all audio of the phone call being recorded].

In my case, this results in audio from both sources (microphone and cell phone) of comparable levels. Levels can be adjusted with the “ + INPUT LEVEL – ” toggle button on the side of the TASCAM DR-40, with further fine tuning of the level coming in from the phone with the phone’s volume buttons.

It is clear that this cool TASCAM recorder has many more tricks up it's sleeve, and that adding some more simple gear will result in more functionality and even better results.

Cheer!