Help needed -- my pair of AKG C451B is really noisy

[Doug Young]

Interesting, hard to know what to make of this. But a couple of thoughts:

You really need to have a reference level to compare the noise levels. Use your ipad or whatever to generate a 1KHz tone and set the mics to product the same level of output on the recording for the test tone, with the tone generator in the same spot. You really can't say how much noise is too much noise (aside from being bothered by it!) without a fixed level to compare it to.

The AT track is mono, the AKGs are stereo, right? That seems to account for some of the aparent difference in sound quality. I'd try mono-to-mono for comparing and tracking this down.

To me, the noise of the AKG's sounds very much the same as your outside ambient noise. When you open the door, the character of the sound is about the same, just louder. The sound is also very much like a computer fan.

Your room sounds pretty lively, based on your voice. No acoustic treatment? That might help a little.

The noise you're getting here, at least, is a nice steady sound. It's pretty loud, on the pure noise tracks, but there's nothing to compare it to. It's really not that noticeable on most of the guitar recording, and it could be eliminated with noise reduction. Not ideal, but if you live in a noisy environment, that may be life.

[sdelsolray]

Originally Posted by JoeCharter

Yes I understand your latter point.

I set the level the same just for comparison purposes.

When I recorded with the AT, I set the level much lower (no noise).

I do like the airiness of the AKG but there's no way I can drive these to decent levels in this environment without audible background noise.

Yes, you set the preamp input gain level the same, but all that does is show what happens when the preamp gain is set the same. That is not a relevant comparison when trying to compare relative noise of two different mics.

Plug in the AT and AKG into different inputs on your Duet. Put the mics in the same location, pointing in the same direction. Play a test tone from an electronic tuner or some other source. Set the input gain level of each channel so that the DAW shows the same input level on the computer. Shoot for a healthy signal level. That might be 52 dB for the AT and 58 dB for the AKG mic, for example. Write down the two preamp settings as well as the signal level in the DAW (e.g., -10 dbfs). Keep that for future reference.

Now, record the ambient noise using those preamp settings, again with one mic in each channel. Listen to the playback (each channel centered) and compare them back and forth.

[JoeCharter]

Originally Posted by Doug Young

Interesting, hard to know what to make of this. But a couple of thoughts:

You really need to have a reference level to compare the noise levels. Use your ipad or whatever to generate a 1KHz tone and set the mics to product the same level of output on the recording for the test tone, with the tone generator in the same spot. You really can't say how much noise is too much noise (aside from being bothered by it!) without a fixed level to compare it to.

The AT track is mono, the AKGs are stereo, right? That seems to account for some of the aparent difference in sound quality. I'd try mono-to-mono for comparing and tracking this down.

To me, the noise of the AKG's sounds very much the same as your outside ambient noise. When you open the door, the character of the sound is about the same, just louder. The sound is also very much like a computer fan.

Your room sounds pretty lively, based on your voice. No acoustic treatment? That might help a little.

The noise you're getting here, at least, is a nice steady sound. It's pretty loud, on the pure noise tracks, but there's nothing to compare it to. It's really not that noticeable on most of the guitar recording, and it could be eliminated with noise reduction. Not ideal, but if you live in a noisy environment, that may be life.

Yes, the AKG track with the Kraut is stereo while the Olson was recorded in mono.

There is no room treatment right now but I have a 10x10 space that might be a good candidate.

In any case, It's reassuring to hear your thoughts and those of other competent folks here.

I'll keep working with the mics and see what I can come up with. Obviously my goal isn't to come up with world class recordings -- just nice enough to be worth listening to.

Thanks very much for taking the time to share your thoughts.

[GregEL]

Didn't see any mention of how you have the pad switch set. I recorded something once with the pad set at -20 and got some barely noticeable hiss. Set the switch at 0 and the hiss (sounded a little like wind) went away.

Good luck!

[JoeCharter]

Originally Posted by GregEL

Didn't see any mention of how you have the pad switch set. I recorded something once with the pad set at -20 and got some barely noticeable hiss. Set the switch at 0 and the hiss (sounded a little like wind) went away.

Good luck!

I thought of the same thing -- they were both already set at "zero" unfortunately.

I played around with the AKGs again last night and while I'm pleased with the tone, my environment may not be suited to those mics.

I am now considering getting a pair of Neumann TLM 102/103 and get it over with.

[rick-slo]

Originally Posted by JoeCharter

I thought of the same thing -- they were both already set at "zero" unfortunately.

I played around with the AKGs again last night and while I'm pleased with the tone, my environment may not be suited to those mics.

I am now considering getting a pair of Neumann TLM 102/103 and get it over with.

Before you send the mikes back try recording one of those mikes instead of the pair and compare that. It may be a single mike versus two mike thing in your recording space.

[Doug Young]

Originally Posted by JoeCharter

I thought of the same thing -- they were both already set at "zero" unfortunately.

I played around with the AKGs again last night and while I'm pleased with the tone, my environment may not be suited to those mics.

I am now considering getting a pair of Neumann TLM 102/103 and get it over with.

If the issue is noise from your environment, pretty much any mic sensitive enough to pick up your guitar, will also pick up the room. You might have a tiny bit more luck with a hyper cardioid, but in general, you can either reduce the noise somehow, or increase the level of the guitar relative to the noise by micing closer. I don't think different brands of similar mics is very likely to solve the issue, tho

[JoeCharter]

Originally Posted by rick-slo

Before you send the mikes back try recording one of those mikes instead of the pair and compare that. It may be a single mike versus two mike thing in your recording space.

Yup, I did that just now.

https://soundcloud.com/syndicatedarts/at-vs-akg/s-mj9OY

Thanks for your continued help on this, Rick.

[JoeCharter]

Originally Posted by Doug Young

If the issue is noise from your environment, pretty much any mic sensitive enough to pick up your guitar, will also pick up the room. You might have a tiny bit more luck with a hyper cardioid, but in general, you can either reduce the noise somehow, or increase the level of the guitar relative to the noise by micing closer. I don't think different brands of similar mics is very likely to solve the issue, tho

Thanks, Doug.

I know nothing about recording and I am happy to be corrected -- but so far I find that my larger diaphragm AT allows my guitar to fully come through while it is set at a lower volume (thus picking up less distant ambient noise).

The mono recording I did with the AT isn't as "lively" as the one with the pair of AKGs -- but the S/N ratio seems so much better.

[ombudsman]

I've heard a lot of complaints about that mic being overly bright and harsh. AKG's marketing says that the current 451B capsule has "acoustically identical" performance to the old CK1, but the frequency response plots show otherwise. (It may be that the extra highs in the current model are coming from a fixed EQ built into the amplifier circuit, which could make their statement techically true but practically false without a defeat switch adn since the 451B is not part of a modular system.) The high end boost in the 451B is considerably larger even than the CK1S which was a brighter version of the CK1.

I've got some old CK1/451E and I consider those unusably bright for many sources, so it does not surprise me that the 451B turns some people off.

There's no reason you can't split the difference by putting a smaller presence boost on the track recorded with the AT.

[Fran Guidry]

The AT3035 is one of the all-time great microphones, but it is handicapped by the fact that it didn't cost a lot, wasn't styled for visual impact, didn't have any magical features like tubes or ribbons, was produced in large volumes, and didn't have a German (or Austrian) name on the label.

Fran

[mjz]

Originally Posted by ombudsman

I've heard a lot of complaints about that mic being overly bright and harsh. AKG's marketing says that the current 451B capsule has "acoustically identical" performance to the old CK1, but the frequency response plots show otherwise. (It may be that the extra highs in the current model are coming from a fixed EQ built into the amplifier circuit, which could make their statement techically true but practically false without a defeat switch adn since the 451B is not part of a modular system.) The high end boost in the 451B is considerably larger even than the CK1S which was a brighter version of the CK1.

I've got some old CK1/451E and I consider those unusably bright for many sources, so it does not surprise me that the 451B turns some people off.

There's no reason you can't split the difference by putting a smaller presence boost on the track recorded with the AT.

My experience with 451B's mirrors this.
We use them when we record darker guitars and want to punch the crispy, brightness. But our studio is designed to handle their propensity to accentuate these frequencies. They are wonderful for cymbals in drum overheads because of this characteristic.

We have also found that when recording wooden guitars, 1/4 inch difference in placement and angle makes a world of difference in how they reproduce the sound of the guitar.

They are great tools in the arsenal, but if the studio has limitations and you are recording without assistance, they may be problematic.

max

[rick-slo]

Originally Posted by JoeCharter

Yup, I did that just now.

https://soundcloud.com/syndicatedarts/at-vs-akg/s-mj9OY

Thanks for your continued help on this, Rick.

Interesting how differently the mikes pick up the sound of the computer in the background- I assume you used the same mike position for both and mike were pointed more or less directly away from the computer.

[Doug Young]

Originally Posted by JoeCharter

Thanks, Doug.

I know nothing about recording and I am happy to be corrected -- but so far I find that my larger diaphragm AT allows my guitar to fully come through while it is set at a lower volume (thus picking up less distant ambient noise).

I think you're confusing the gain staging. A mic can't tell the difference between a noise in the room and your guitar. If you turn down a preamp, you are turning down the overall gain, and therefore turning down *both* the guitar and the noise. There are lots of variables tho. Your AKG seems to have a presence peak, which may be making the noise more obvious, or at least sound different. But if you change that, you are also changing the way those frequencies are picked up from the guitar.

Noise is a fact of life, very few places on earth are really quiet, mics make noise, preamps make noise, etc. The thing that matters is the signal to noise ratio. So the first thing to do is determine where the noise is coming from. For example, if the noise is coming from your preamp's input stage, then the more you turn up the preamp, the more noise you will hear. In that case, you can reduce the noise by turning down the preamp, and increasing the level of the sound coming in - a mic with more output, mic closer to the guitar, play louder, etc. If the noise is coming from your room, that's different. In that case, turning down the preamp, will lower the overall noise level, but also lower your guitar level. Then when you mix, and bring the level of the guitar up to a normal level, the noise will come up with it. In that case, you have to figure out how to either increase the level of the guitar, or lower the noise. There are lots of ways to do that. If the noise is coming from some direction, a more directional mic may help. Blocking the noise can help. Playing louder can help, putting the mic closer to the guitar can help. But simply getting a mic that has less output just turns down everything, including your guitar, and then you'll need to turn them both up, either in the recording, or the mix. If the noise is coming from your environment, I don't think you'll find all that much difference with respect to your issue with any reasonable mic choice - large diaphragm, small, whatever - if the mic is sensitive enough to pick up your guitar, it will also pick up the noise.

My suspicion is that the differences between the AKG and AT will mostly go away if you do a level-matched test - set the levels to be the same with a test tone. There may be some perceived differences due to the AKG's presence peak, but if you like the way that sounds on your guitar, then it's part of the package. If you can find a mic with less treble response then the noise might seem to be reduced at those frequencies, but then so will your guitar! Of course, you might like the sound, so that's ok,

[myersbw]

Just curious...what software are you using to do the actual recording? And, are there some AGC (automatic gain control) settings that might be on? I've also seen some OS settings that use AGC and need to be unchecked (turned off). Your files don't have that typical characteristic, but it's worth checking.

FWIW,
Brad