Topic: Edirol R-09 buzz w/ external mics

[echo1434]

In my last two recordings I've noticed some weird static pops, and sometimes one channel will fade out for a split second (which is very noticeable). This is my setup:

DPA 4061s > Core Sound HEB battery box > Edirol R-09 (line in)

I just tried re-creating this at home, and I noticed there's this weird static type buzz that happens when I take the recorder in and out of my pocket. Now, I'm not sure if it's a connection problem because I can yank on the cable and the input pretty hard and this noise doesn't happen. I can even twirl the cable in the line input and there's no noise. But as soon as I move the recorder up and down (usually by taking it out of my pocket), there's this noise.

I actually have two R-09s, and this happens on both of them – and it seems to only happen when 1) I'm running external mics and 2) when I take the recorder in and out of my pocket.

I tried making this static on purpose while using the internal mics, and it didn't happen. So I think it has something to do with using the external mics.

I've tried eliminating all variables here, but the the only common denominator is using line-in + taking it and out of my pocket. Pretty much anything else (including pulling on the cables in an excessive manner) will not cause this problem. So I'm just really baffled here.

You can hear two samples I made. Please note that these have been amplified to show the noise (although these blips/droputs are still quite apparent against loud music).


http://www.uyeasound.com/samples/r-09_dpa_line_in.mp3

http://www.uyeasound.com/samples/r-09_internal_mics.mp3


With the built-in mics, you can just hear me scratching the Edirol inside my pockets and on some other fabric – but no static buzz.

I'll also note that I've recorded about 14 concerts before this problem ever appeared on my recordings – but now it occurs on both my Edirols.

Any help would be greatly appreciated! 

[digifish_music]

In my last two recordings I've noticed some weird static pops, and sometimes one channel will fade out for a split second (which is very noticeable). This is my setup:

DPA 4061s > Core Sound HEB battery box > Edirol R-09 (line in)

I just tried re-creating this at home, and I noticed there's this weird static type buzz that happens when I take the recorder in and out of my pocket. Now, I'm not sure if it's a connection problem because I can yank on the cable and the input pretty hard and this noise doesn't happen. I can even twirl the cable in the line input and there's no noise. But as soon as I move the recorder up and down (usually by taking it out of my pocket), there's this noise.

I actually have two R-09s, and this happens on both of them – and it seems to only happen when 1) I'm running external mics and 2) when I take the recorder in and out of my pocket.

Any help would be greatly appreciated! 

I have noticed the same thing with SP-TFB-2's. I think you will find this happens when you touch the recorder. Try squeezing it, the harder you squeeze the more digital interference you will get. Perhaps the squeezing of the case brings something into contact with the circuit board? I didn't look to see if the inside shell of the R-09 case has a anti-RFI coating.

It seems our bodies act as a conductor/antenna/amplifier of the R-09 internal digital noise and it is picked up by the delicate capsules. I think. I check all my recordings with a spectrogram...here's yours...



...and the interference shows up as a series of harmonic frequencies. This is the same as I get, but yours is much louder. The solution has been to have no contact with the recorder and or mics while recording (hard I know in a binaural stealth mode I suspect these small electrets are not well shielded?

BTW: I have only seen this with the MIC in, not LINE. But I have never used my binaurals with an external mic preamp. My phantom professional mics through an Sound Devices MiXPre are clean...very clean.

If it has suddenly appeared I would suspect that something has changed with your mics or pre-amp? Or have you moved into a more humid/dry season than before?

digifish

[echo1434]

Nothing has changed with my setup at all. As for the weather, I'm in the Midwest U.S. and I started taping this summer, generally under very hot and humid conditions. All those recordings came out clean.

This static/dropout problem started about a month ago. The weather is now very cold and dry, but these were indoor venues where the temperature was still a bit warm.

I ran some more tests, and this DOES NOT occur from simply touching the recorder. I tried squeezing it and putting my hands all over it, and there was no interference. However, as soon as I slide the recorder into my pocket (and back out), that's what causes the noise. It seems crazy, but I guess the friction of it rubbing against my pants creates enough static for that to happen?

I've tried this with three different types of pants with different material, and it's all the same. I try to take the recorder in and out extra carefully and slowly, but it doesn't really help.

Granted most of this interference is occurring at a level below -50 dB (which you can't hear against loud rock music), the static is sometimes strong enough that it will cause a momentary blip or channel dropout — which is a huge problem.

I'm perfectly happy with my setup and have made some fantastic sounding recordings, but the fear of having a couple pops/dropouts during every show has really gotten me down.

Ok, so maybe I need to keep my levels checking to a minimum from now on, but it's still something I'd like to do at least a couple times at every show. Is there any feasible solution to this, aside from wearing rubber pants? 

[pjdavep]

I'm assuming you can't try another mini cable because it's fixed to your HEB battery box?  That would be my guess.  The straight mini plug cables have a lot of strain put on them and it's possible that when you are reaching in/out of your pocket that you are bending the cable at the strain relief portion an that is making the noise? 

Later,
   pjdavep

[echo1434]

I'm assuming you can't try another mini cable because it's fixed to your HEB battery box?  That would be my guess.  The straight mini plug cables have a lot of strain put on them and it's possible that when you are reaching in/out of your pocket that you are bending the cable at the strain relief portion an that is making the noise?

I have a right angle plug, but you're right, the cables are fixed to the mics. Unfortunately, I don't have any other mics/cables/other rigs to makes any tests.

[digifish_music]

Just to be clear, what you are hearing here is not 'static' from your pocket. You are picking up momentary bursts of digital interference from the R-09 circuits.

Are you wearing the microphones when you touch the recorder?

In my case I need to be touching both the recorder and the microphones for this to happen, and not necessarily with my skin, I just need to be in physical contact through clothes etc.

If only touch the recorder or mic then it doesn't happen. It's a little like a digital-ground-loop ... i.e the digital noise passes through us to the mics. I really think this has something to do with the lack of good shielding on these types of mics and their rensitivity.

It is possible that the dry weather causes the problem? Where I am in Australia it's very low humidity all year around and I can make it happen any time.

digifish

[it-goes-to-eleven]

Very interesting......

If you send your r09's earphone out into your PC soundcard, you should be able to visualize handling noise in realtime.  I'm sure it will be a lot easier to see then try and hear.  I like to use baudline for that under linux. Not sure what would work best under windows.

[echo1434]

Are you wearing the microphones when you touch the recorder?

In my case I need to be touching both the recorder and the microphones for this to happen, and not necessarily with my skin, I just need to be in physical contact through clothes etc.

If only touch the recorder or mic then it doesn't happen. It's a little like a digital-ground-loop ... i.e the digital noise passes through us to the mics. I really think this has something to do with the lack of good shielding on these types of mics and their rensitivity.

At concerts I have my mics mounted to my glasses, and this problem occurs. When I tested it at home, I tried 1) both wearing the mics + putting the recorder in my pocket and 2) with the mics sitting on my bed + putting the recorder in the pocket of some pants lying on the bed.     (I was not on the bed.)

Either way, it's the same. So no, I don't have to be wearing anything or touching a certain combination of things for this to happen.

I'll try running the earphone out into my soundcard sometime, but for now I'm still utterly confused. 

[echo1434]

I sent my mics back to Core Sound to have them checked, and they replaced one of the cables and the connectors. That fixed the problem.

It seems I've been too aggressive in the way I wrap my cables when putting the mics in storage, so I'll have to be more careful in the future.

[jeromejello]

thanks for the update.  maybe that will help someone else out down the road.

[digifish_music]

thanks for the update.  maybe that will help someone else out down the road.

Indeed...so something had changed, you had lost some grounding/shielding on a cable by the looks of it. But do we blame the mics or does the RFI from the R-09 share some blame too? 

digifish.

[echo1434]

But do we blame the mics or does the RFI from the R-09 share some blame too? 

I don't think the Edirol is to blame. I was able to replicate the problem by plugging my mics into a sound card with a 1/8" input and slightly wiggling the input jack.

It turns out that the problem was at or near the right angle mini plug on the mics, and when the plug was bumped or moved the slightest amount while inside the input hole it would cause the static/dropout. Oddly, the force needed to create the problem was most easily created by taking the recorder in and out of my pocket, and didn't occur under many other conditions.

The problem was more difficult to pinpoint when I first posted this thread, but then it just kept getting worse and worse, to the point where moving the Edirol the slightest amount while holding it in my hand would cause the problem.

I'm just glad to have it fixed. It was getting to the point where I was afraid to make the slightest movement or even touch my recorder while at a concert, and that's definitely no fun.