Not many post about the AKG C411...

[rgp]

Don't see much about this mic in the discussion of small condensers. Can those who have used it compare it with others such as the DPA, AT350, or Jim Mills. Thanks

[mandotim1955]

I have one, and love it. I gig with it regularly on a Gibson F5, and it does a good job. Plenty of gain before feedback, easy to take on and off the mandolin. I play it through a Headway EDB 1 preamp/eq, and this gives a really good signal to the board. I've experimented with a lot of different approaches, and this is the best imho if you don't want to run to the big bucks of DPA or Schertler. The AT350 is nice, and so is the K&K range (mandolin twin pickup or Silver Bullet mic), but the AKG C411 shades it on tone and ease of gigging.

[foldedpath]

Don't see much about this mic in the discussion of small condensers. Can those who have used it compare it with others such as the DPA, AT350, or Jim Mills. Thanks

It's not usually mentioned in discussion of mini condenser mics because it's not really a "small condenser" in the usual sense. It functions the same as a piezo contact pickup, by sensing local vibration from the soundboard. A microphone like the ATM350, DPA 4099, etc. captures the sound of the instrument as it develops through free air, and from both the vibration of the top and the sound of the resonant airmass inside the body (depending on where you place it).

So while the C411 might be a good option for those looking for a pickup, it's usually discussed along with other pickup options like the K&K, Schertler, Baggs, and other options because it won't sound like a microphone.

[mandotim1955]

The C411 is not a piezo pickup. It uses similar technology to the boundary microphones used in conference rooms; these are put on a flat surface, and pick up omnidirectionally. There is no piezo element in the device, it uses a very small electret condenser mic. I've bought and used a wide variety of good quality piezo pickups, and the C411 doesn't sound remotely like any of them. Nothing beats the sound quality of well placed, high quality condenser mic; but in 'real life' gigging situations this is often not a practical proposition. A compromise is needed, and the C411 (for me) is a good compromise. It sounds better than a piezo, and rejects feedback much better than clip-on microphones. It's also less bulky and obtrusive than most of the clip on mics. The one tip I have about using it is to get a good preamp with good eq and a phantom power output, and buy the version that requires stand-alone phantom power. Proper EQ can work wonders, and I find the Headway EDB1 very good for this.

[Toni Schula]

I used to use an AKG C411 when
- I played Mando with a rather loud electric band
- I only had my rather quiet old Mandolin.

In this set-up using a transducer which has rather a pick-up characteristic than being a microphone was essential. But I never liked the sound. I even tried to blend with a clip on mic (which was an inferior Chinese clone of an AKG clip-on mic for Sax) without ever being satisfied with the sound.

Now, that I have
- a very loud and great sounding Krishot Garnet F mandolin
- and use a DPA 4099 (through a Joemeek ThreeQ preamp plus a Morley optical volume pedal in the insert)
- and play in a purely acoustic string band with hand percussion (Cajon)
I never used the C411 again.

With this set-up I am for the first time very satisfied. At least with the sound I get. As for the mando playing itself: there will never be the time when we cannot further improve it

So far we had the good luck, that it was never too windy when we played outside, so wind noise was never an issue.


By the way this Thread contains also some info on the C411:
http://www.mandolincafe.com/forum/sh...at-contact-mic


Cheers
Bauzl

[mandroid]

Probably more comparable with a Schertler Basik. both electaret/condenser contact transducers..

Schertler's Dyn M is their dynamic type contact transducer ,
All a microphone made to use the soundboard as the diaphragm..

[adrjork]

Hi guys, Im' a newbie here!

My problem concern this set:
1. Macbook Pro Retina without Power adatper (only battery) +
2. Babyface Pro without Power adapter (powered by USB3) +
3. AKG C411 contact mic (48v phantom powered) +
4. Beyerdynamic DT 770 PRO 250 ohm headphones (connected to the RME).

The problem is: listening to my recordings, I hear a sort a low "harmony", a sort of (tuned) resonance.

I'd thought it is hum issue, but I don't use Power adapter on my laptop, nor on the Babyface (powered by USB3)...

So, if it's really a hum issue, what is the reason: mac battery? USB3? phantom? 250 ohm headphones? human capacitance?
But mainly: at which frequency I have to set the DeHummer?

Thanks for your help.

[Toni Schula]

Hum from a battery? No. This would be the first AC battery in history.

Your problem sounds strange to me. With an external USB audio interface even electromagnetic noise inside a computer should be ruled out.

For troubleshouting I would change one component at a time to find the guilty one.
Some easy things to try:
- do you hear the same noise with the phantom power switched off? The step up converter from USB 5V to 48V would be my suspect here.
- Do you hear that noise while listening to audiofiles instead of the mic?
- Do you hear the same noise with a mic instead of the C411? If you do not have a mic at hand you could try a 200 Ohms resistor and should hear as much as with the first test: nothing
- Is the noise (much) louder when the inputs left open? Then the combined impedance of C411 + Preamp is too high to supress it enough. Otherwise its source is further down the road in the signal path.
- I would not expect the headphones to cause trouble, nut you could check that as well with annother type.
- Try to connect to annother computer would ne the last thing in my list.

Good luck
Bauzl

[adrjork]

Thanks for your reply.

I've tried with a "normal" mic (AT4041) and no hum with it. And no hum in audiofiles in general (but files recorded with the C411 do have hum issue!) The problem is quite surely the C411 itself: the cable is too thin and captures all interferences in the area (also mac wi-fi antenna if activated). All these interferences are evident, I can hear them immediately. But this hum issue is subteler... It's not so evident. I'm almost sure that is a 50Hz freq (I tried to isolated it with parametric EQ).

Thank you Bauzl.

[almeriastrings]

I have used multiple C411's, even at full cable length, in electrically 'noisy' areas quite often (around wireless mics, stage lighting and in-ear monitor systems, amplifier backlines, etc). We have have never had this problem. I think you have a grounding issue. The thickness of the cable has nothing to do with it (the C411 cable is almost twice the diameter of the DPA 4099 cable, for example).

Without a physical connection to ground/earth, the cable shielding will be a 'floating' ground - and this is frequently a cause of problems such as those you describe. This transducer system is not designed for use with a floating ground, but with a 'true' ground, as offered by a mixing console or professional preamp. Laptop systems and USB connections are notorious for causing a variety of ground-related problems with sensitive audio equipment - precisely how a particular microphone or transducer behaves can vary. The C411 is also unusual in that you are taking the +5v from the USB port... boosting it to +48v using the RME, then reducing that yet again via the AKG's 'Phantom adapter' (which uses yet another voltage converter circuit to reduce the 48v to around 7-8v to bias the electret element). I would suggest trying it by using a fully grounded separate phantom power supply between the Babyface and the C411. Turn the internal +48v on the Babyface off - just insert a good quality properly grounded standalone phantom PSU (or for test purposes, a separate grounded preamp) in series. That should resolve the issue, hopefully.

[adrjork]

Thanks you almenriastrings! Surely I'll do this test!

[almeriastrings]

One other thing you can do is to try grounding the Babyface directly.

This can be done in several ways, by connecting it to an other equipment that has a true ground, for example.

In my workshop I have a cable with one end connected to the copper pipe on my central heating system (which I know is very well grounded) and the other end has a small alligator clip.... I use this when tracing possible ground faults. If the hum goes away when the clip makes contact with a part, then I know the grounding is damaged or not adequate.

There should be no audible hum or buzz from your AKG C411. There is definitely something wrong if there is.

I just plugged one into one of my studio preamps last night, a UA 6176, and there was zero hum or background noise even at maximum gain.

[adrjork]

I think this could be the right way. I'll surely test it. Thanks a lot for your clever advice.

[Polecat]

Almeriastrings is probably right, it sounds like an earthing issue; one thing came to mind, though - are you using the AKG adaptor? these electret mics run on about 5-10 Volts (the AKG adaptor puts out around 6.5), if you're trying to run it on the full phantom power from the preamp (which is likely less than 48V), strange things will happen. I once killed an electret mic through ignorance by hooking it up to 48V - before it died, it picked up a lot of electric noise including fluorescent lights, the radio, and any motorbike that drove by.

[adrjork]

Hi Polecat, there are 2 versions of the C411: L and PP. To connect the L version to XLR you need to add a cable named AKG MPA VL Male - phantom power adapter. The PP version is XLR native, but on the XLR connection there is written Phantom Power Adapter.
Perhaps both versions use the same technology. Anyway, I own the PP version (XLR native) and I must say that if you unscrew the XLR block you can see that the thin cable is "eaten" by the XLR connection...

[Polecat]

The C411PP comes with the adapter included (I've just checked). The problem is not an incorrect voltage - it's almost certainly an earthing issue, then.

[adrjork]

I guess so. But why does this problem afflict a C411 and not a "normal" cardioid like AT4041?

[mandroid]

Check for an Open Ground (Aka earthing) TRS & Mic cable have 3 conductors,

ground is the braided shield around the twisted pair carrying the signal .

may be just yours has that issue , not all C411.. you own several and find it common?

[adrjork]

No, just one. I'll buy another one, but this time I thought the C411L + MPA XLR adapter. The reason is that - as I said - in the PP version the cable is badly nipped by XLR connection itself, and I don't like it at all.

[almeriastrings]

This is what is inside the AKG XLR adapter (Micromic II) - in fact, a Phantom to AB type PSU and integrated preamp.



It is not just a simple cable adapter. Note that it takes the balanced XLR on one side and the actual C411 itself is running a two-wire, unbalanced configuration - hence more susceptible to hum pickup if the overall grounding is not adequate.

[adrjork]

Thank you almeriastrings! Very clear indeed.