Yet Another Preamp Suggestion Request...

Posted: Sat Mar 08, 2008 5:28 pm

IainDearg wrote:

Vox is overdubbed.

What mic do you use for that? One of the KM184s? Or something else? Does it have a bidirectional response, by any chance?!?!

IainDearg wrote:

I use X/Y setup exclusively for the guitar. SNIP! Any spaced technique made my guitar sound as if it was 25' wide when listened to through monitors. SNIP!! So I cheat a little bit by adding some width with my favourite plugin (Voxengo's Soniformer) which uses a mid-side algorithm.

All very interesting information, Iain.

MS may be worth a try for you because you can vary the width, and it seems that width is what you're lacking. That's not surprising with XY cardioids at 90° - they actually require a 180° soundstage to create an image that extends from hard left speaker to hard right speaker (assuming the speakers are set up in theoretically optimum equilateral triangle with the listener). With a 3' wide guitar miked at 18 inches (as you have said), you're capturing a 90° soundfield with a technique that has an angular compression of about 3:1 (e.g. 180° soundfield is reproduced as a 60° soundstage, so 180:60 = 3:1). So, your recorded guitar is probably sitting in the middle 90°/3 = 30° of the 60° wide stereo soundstage - in other words, from mid-left to mid-right. Probably a tad narrower than you'd like and right in the way of the voice (without the widening you apply).

Does that description sound close to what you're getting?

Getting back to MS... Unlike the XY you're currently using, MS will give a very solid centre image, which might conflict with your voice. With XY, the centre image can be ever-so-slightly vague, which makes a nice 'hole' for a solid voice to sit.

Here's a little known technique that the late great Michael Gerzon wrote about, and which you can probably do well with your KM184s. Try crossing the microphones one over the other, with a spacing of 5cm between the diaphragms and an angle between 115° to 120°. According to Gerzon, "Such 5cm-spaced crossed-over cardioids, angled about 115° to 120° apart, seem to be an optimal cardioid technique for stereo imaging accuracy."

This technique was mentioned in the sorely-missed Studio Sound magazine in July 1986, referring to the use of stereo shuffling (a bit like doing MS widening but only on the low frequencies, and something you can easily do with Waves' S1 imager). He wrote: "The use of bass-widening up to 600Hz with this technique seems to give a much better sense of space than the use of ORTF technique, and without the latter's 'phasiness' anomalies."

I tried this technique recently with a pair of Audio-Technica AT4051 cardioids. It was very rushed - recording a handful of hungry musicians on the porch of hut in a village in the Himalaya, moments before dinner was served - and I didn't have enough time to fine-tune the position or angle, but I could tell that it had a lot of potential. I intend to do more with it in the future.

Maybe you could give it a try...

Posted: Sat Mar 08, 2008 5:53 pm

taxman wrote:

This forum does not rate the 184 highly.

That usually occurs when people are discussing the KM184 with a view to purchasing one (or a pair) as a general purpose small diaphragm condenser. But I think it is good for many things.

The sound is a bit bright, but it's still a Neumann with all (or most) of the tonal qualities we expect from Neumann. It does not sound cheap, to my ears. It's clean and quiet, and nicely priced IMHO. There are much worse mics out there.

Also, I think much of the 'disdain' one sees for the KM184 comes from people who were expecting it to sound like the wonderful and sweet KM84. Neumann don't make the KM84 any more; the replacement they offer is the KM184, which is not the same thing - brighter and not as sweet.

taxman wrote:

Does the AKG C451B cut it? Or do I have to go to Schoeps, Earthworks or DPA?

I have always found the 451s to sound 'chalky', as if someone drew the sound's envelope on a blackboard with chalk. I used to own a pair, but rarely ever used them for anything more than overheads on drums, or hi-hats. On acoustic guitar, I felt that they brought out all the scratchiness I was trying to avoid, without giving anything worth keeping. In comparison, the KM184 may be bright, but it's not chalky! (Sorry AKG...)

You can't go wrong with a cardioid from Schoeps or DPA, depending on the sound you're chasing. Also, those Mojave's that Jeremy posted a sample of are definitely worthy of consideration. I'd like to hear just one of them, without the contribution of the other mics in the shots, to know for sure.

Posted: Sat Mar 08, 2008 8:40 pm

Simmosonic wrote:

Also, those Mojave's that Jeremy posted a sample of are definitely worthy of consideration. I'd like to hear just one of them, without the contribution of the other mics in the shots, to know for sure.

Just fyi Simmo -
The guitar sound is all Mojave. The Royer isn't on this clip. Also, the vocals were tracked later, so there's no impact from that - just the Mojaves on guitar.

If you'd like, I can get you the same sample sans vox so you can hear just the Mojaves.

The pipe organ sample will be nice too except that the Schoeps CMC 6 MK 2s's are up front and the Mojaves are mid-hall. It's still a VERY nice and complimentary sound.

Anything that you want clips of where it's JUST the Mojave's, let me know.

J.

Posted: Sat Mar 08, 2008 8:47 pm

Cucco wrote:

If you'd like, I can get you the same sample sans vox so you can hear just the Mojaves.

Oi! Why not!?!? Bring 'em on...

Posted: Sun Mar 09, 2008 5:45 am

Simmosonic,

For vocal, I use an oldish AT-4033. No bi-directinality there.

You know, I've never crunched the numbers in this way - very enlightening! And yes, the subjective results is what you describe - tight and uninvolving (and a wee bit muddy althought not as troublesome since I installed acoustic treatment in the room.)

I'm a bit confused: you wrote viz XY that the guitar was sitting mid-left to mid-right (I can see this intuitively by thinking about the mics' response patterns) but "right in the way of the voice". Later you wrote that XY "makes a nice hole" for the voice. This seems contradictory - am I misunderstanding?

I can also see that MS with the cardioid pointing straight at the guitar might get in the way of the centrally positioned voice (which mine invariably is).

The Michael Gerzon technique sound fascinating - I note the lack of "phase anomolies", the bane of my recording attempts for so long. I'm going to try it out next time I get in front of the mics.

(I wonder whether XY angled wider than 90 degrees might give similar results?)

What I've been trying to achieve is something that sounds like a performance - an illusion of a player sitting on a chair on a stage at a realistic distance from the listener - at least when heard through a hi-fi. That and capturing the snap and growlines in my Martin OMs. I'm not wanting "larger than life" recordings.

With respect to the scathing comments on the KM184 that one reads: they've always puzzled me since they represented a quantum leap in the quality of my recordings for me. I take on board their inherent brightness and that they don't match up to the old KM84s and others, but what I have never seen satisfactorily explained (to me) is why judicious application of eq is not a reasonable approach to take to this brightness. Is there a technical reason why this is "wrong"?

Cheers.

Posted: Sun Mar 09, 2008 4:33 pm

IainDearg wrote:

For vocal, I use an oldish AT-4033. No bi-directinality there.

Okay...

IainDearg wrote:

I'm a bit confused: you wrote viz XY that the guitar was sitting mid-left to mid-right (I can see this intuitively by thinking about the mics' response patterns) but "right in the way of the voice". Later you wrote that XY "makes a nice hole" for the voice. This seems contradictory - am I misunderstanding?

No, but you are reading what I've written very carefully and found an ambiguity, damn it! I'd better explain myself...

Let's start with "right in the way of the voice". Here I was referring to a stereo mix with vocals and acoustic guitar, each miked and recorded separately, so we are essentially in multitrack mixing world with faders and pan controls. The philosophies of direct-to-stereo work don't have to apply here.

We have a relatively wide soundstage available (+/-30 degrees either side of centre, if the speakers are set up according to the theoretical ideal), throughout which we can spread the acoustic energy of the recording. It would probably sound odd if you spread all the direct energy of your guitar/voice recording throughout that width; keeping it within, say, +/-22 degrees (so that it creates a 45 degree image) is probably as far as you'd want to go. The remaining outside edges are best left for reverberation...

As I calculated earlier, your XY guitar recording begins life with a 30 degree window (+/- 15 degrees either side of centre). Left as it is, that puts the bulk of the guitar's energy within the central 30 degrees of the 60 degree soundstage that is available to use. If we then place a centrally-panned voice over the top of it, we're placing all the recording's energy around the middle of the soundstage. Apart from wasting some of the available soundstage (for what that's worth) this also makes it harder for the ear/brain system to distinguish and separate the two sounds; hence, the guitar sound is getting "in the way" of the voice.

As I'm sure you know, one of the easiest ways to create separation between two sounds is to pan them apart. So the idea is to try and 'pan' that guitar energy away from the voice, in both L and R directions at once, by spreading its energy a bit wider and thereby making it a bit 'thinner' behind the voice so there is less conflict. This is what you are doing when you use MS widening on the guitar - whether it's your intention or not, it's happening and making your mix sound better.

Now let's tackle my notion that XY "makes a nice hole". Imagine that you are a sound source in the centre of the soundfield that your 90 degree XY pair is recording. What do you see? You are not coming directly on-axis to either microphone; in fact, you are arriving at 45 degrees off-axis to two microphones, and relying on a pair of speakers to recreate you as a 'phantom' image, miraculously floating in the air between two speakers.

In effect, you are what I call a 'double phantom' image - you were captured off-axis to two different microphones, and you are being recreated in the space between two different speakers. Your 'solidity' is dependent on how well those two microphones were matched in their off-axis responses, how well the speakers are matched, and what the acoustics of the listening room are doing. In the best of all possible worlds, you're recreated as a nice and solid sound. But in less-than-ideal real-world situations (affordable mics, typical speakers, non-symmetrical room acoustics in the playback environment, etc.) you're not a solid sound at all - certainly not compared to a) sounds captured directly on-axis to one of the two microphones, and b) sounds reproduced entirely from one speaker only. You're actually a bit weak in comparison to those sounds, and they find it easy to push you around and dominate you.

Now imagine that you are the vocal recording. You have been captured on-axis with a single microphone, and panned to the centre. Unlike the guitar, you are what I call a 'single phantom' image, and are likely to be a bit more 'solid' sounding. When you are panned to the centre, the only thing you have to compete with is a weaker 'double phantom' image of the centre of the guitar. No problem. You can sit solid in the centre, with a more solid guitar sound to your left and right. Nice...

This is what I meant by a "hole". Not a hole in terms of nothing in the centre, the guitar sound is still there where it ought to be. But the energy in the middle is easier for the vocal to compete with. Think of it more as a soft spot, rather than a hole.

Let's upset the apple cart and use MS to make that guitar recording. Now we have a single microphone facing the centre of the guitar (the M capsule), making it less of a double phantom. The guitar and voice are both now 'single phantoms', and either is less likely to make way for the other.

At this point, you need to ask yourself which is preferable? Trying to fit a great solid mono vocal recording over the top of a great solid stereo guitar recording, or tailoring the stereo guitar recording from the outset so that it naturally leaves a 'soft spot' in the middle for the vocal to sit?

It was the latter approach that reminded me of the technique Gerzon suggested. I think it would offer the best of both worlds, and it is something you can do with your existing mics. Remember, I'm looking at ways to optimise the gear you've got so you can keep your son in Italy for now, and buy a whole kit of better stuff when you can truly afford to buy it!

I hope I've clarified those things, but I fear I've written way too much. If I was to answer this at a different time, I'd probably nail it in one paragraph. Never mind. I also suspect one or two others here may disagree with my 'single phantom' and 'double phantom' concepts, but I hope you get the idea.

IainDearg wrote:

The Michael Gerzon technique sound fascinating - I note the lack of "phase anomolies", the bane of my recording attempts for so long. I'm going to try it out next time I get in front of the mics.

We must be careful with terminology here. I am not sure whether it was Gerzon's technique. I believe it was mentioned/recommended to him by Tony Faulkner. Nonetheless, Gerzon was a true expert in his field, and knew all about microphone phase issues and so on. As I understand it, he invented the Soundfiled microphone, which essentially emulates four(!) coincident microphone capsules (three bidirectionals and one omni) in exactly the same point in XYZ space. He did it by careful combinations of four subcardioid microphones in a tetrahedral array, if I remember correctly. But I digress...

IainDearg wrote:

I wonder whether XY angled wider than 90 degrees might give similar results?

XY techniques typically work from about 80 degrees to 115 degrees or so.

Increasing the angle between your microphones will make a wider image that might sit around the vocal nicely, but it will also put central guitar sounds more off-axis to the microphones. Worth trying, especially if your guitar recording has no important articulation sounds in the actual centre. (A bit of finger picking sounds towards the left channel, and a bit of fret noise towards the right channel perhaps, sitting nicely eiher side of the voice?) It's those articulation sounds that are more likely to conflict with the voice, unless, of course, your guitar is very boomy - that's an entirely different problem.

IainDearg wrote:

With respect to the scathing comments on the KM184 that one reads: they've always puzzled me since they represented a quantum leap in the quality of my recordings for me. I take on board their inherent brightness and that they don't match up to the old KM84s and others, but what I have never seen satisfactorily explained (to me) is why judicious application of eq is not a reasonable approach to take to this brightness. Is there a technical reason why this is "wrong"?

Here are two possible reasons. Firstly, there is the old purist maxim that EQ is bad for the solidity of the sound, because traditional EQ really messes with the signal's phase response. But I think that maxim has past its 'use by' date now that we have linear phase EQ. I still try to live by it, of course, by choosing the best microphone for the job, but sometimes a bit of EQ is preferable to a bad sounding recording.

Secondly, sometimes this brightness is not simply due to a consistent boost of high frequency energy. It may be that the microphone is brigher on-axis than off-axis (DPA, for example, deliberately make microphones with an on-axis HF boost to give them more 'reach'), so any EQ applied to tame the on-axis brightness will usually make the off-axis sounds unacceptably duller.

Or the brightness may due to some kind of resonance, in which case it only gets noticeably brighter above a certain SPL and/or at a certain range of frequencies. Again, a blanket EQ is not going to be the solution.

Finally, the brightness may be due to harmonic distortion of one kind or another. Again, EQ isn't going to help much there, either.

Well, now I have *definitely* written too much, and perhaps veered off into debatable territories at the same time. We'lll see...

Posted: Mon Mar 10, 2008 9:36 am

Thank you so much for the clarification - and the rest. I understand your concepts and I find them really illuminating.

In summary, you said:

Quote:

At this point, you need to ask yourself which is preferable? Trying to fit a great solid mono vocal recording over the top of a great solid stereo guitar recording, or tailoring the stereo guitar recording from the outset so that it naturally leaves a 'soft spot' in the middle for the vocal to sit?

I have to think on this. There are a lot of guitar instrumental passages / breaks in my songs which are of equal importance, according to my aesthetic, as the sung parts. A less than solid central guitar image is something, then, I would like to avoid. I understand, then, that I'm bound to have to compromise. Hey, but it's all an illusion.

I will think on - and experiment - and report back on my conclusions.

Thank you again!

Posted: Wed Mar 12, 2008 9:55 am

IainDearg wrote:

There are a lot of guitar instrumental passages / breaks in my songs which are of equal importance, according to my aesthetic, as the sung parts. A less than solid central guitar image is something, then, I would like to avoid. I understand, then, that I'm bound to have to compromise.

MS might be ideal for you, then. You can widen the guitar image out a little during the vocals so it is not so 'focused' in the centre and therefore lets the vocal sit there nicely, and then narrow it in a bit for the instrumental parts, giving it a good solid sound and bringing it to the fore without making it sound louder. That kind of subtle stuff can work wonders...

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