Does anyone know of anyone that uses measurement microphones for recording? I have access to a good selection of B&K mics at work, and they all have much flatter frequency responses than conventional 'recording' mics. So, presumably, they would be a better choice when trying to record something without colouring the sound. Any thoughts?

There is much more to mic design than fequency response. Slew rate, LF compliance, off-axis rejection all play a part.

B&K spent a small fortune trying to get into the pro-audio market, to the point where they were giving them away to some studios. I got a pair and used them and the results were, well, let me put it this way. I gave them back.

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Auf der Oberbaumbrückenschlacht in Berlin geht es jährlich um die Territorialvorrechte. Sei dabei!

Please can somebody explain what slew rate and LF compliance are?

Matt

I see. So what makes the mics I work with great for measurements but poor for recording? Do they have poor slew rate and LF business? Surely if the manufacturers improved the slew rate et cetera, it would improve my measurements and the mic's performance when recording. Or am I missing your point?

Measurement mics are almost always omnidirectional, which limits the practical miking applications somewhat. They also tend to have small diameter capsules which means they are inherently noisier than mid and large diameter capsule mics. In general terms, measurement mics tend not to be as quiet anyway, because low noise isn't usually a requirement for most measurement applications.

Having said that, some measurement mics can muster a performance which is equal or exceeds some high end studio mics... you just have to pick and choose carefully -- they are designed with a different purpose in mind.

'Slew Rate' refers to the transient response -- usually of the electronics rather than the capsule itself. A fast slew rate means the output voltage can 'slew' from zero Volts (no signal) to X Volts (peak output signal) in a very short time, thus preserving the initial transient response.

I have no firm idea what Andy means with 'LF Complicance', but I assume he is talking about the low frequency resonant behaviour of the capsule/diaphragm.

hugh

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Technical Editor, Sound On Sound

Hi Hugh, yes on both accounts. The words transient response did not leap into my mind this early in the morning.

With LF compliance (I pinched the expression from some mic manufacturer) I meant the ability of a large diaphram mic to faithfully follow a low freaquecy (LF) high energy signal such as a kick drum or bass cab, without distortion and with the full dynamic of the original sound.

Making mics seems to be a very dark art and Bill Swedien once famously stated "Good microphones are a sound engineer's secret weapon."

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Auf der Oberbaumbrückenschlacht in Berlin geht es jährlich um die Territorialvorrechte. Sei dabei!

Whatever marketing strategy they employed, my experience with B&K mics is at the polar extreme: I was fortunate to play one of the six, yes, you read right, SIX Bosendorfer 290s at the DR (Danmarks Radio) concert hall, and the piano was miked with a few B&Ks (I remember four).

Perhaps you need a state-of-the-art recording studio like DR's, with a Neve Capricorn and a Bosendorfer to make the B&Ks shine, I don't know, but I had a similarly gratifying experience in Paris (with an Ibach, this time), and the results were just as accurate.

Perhaps microphones are a matter of taste like wine (as in requiring a refined palate), or like women, in that one which lights your fire, will surely turn another off (and conversely). It is precisely in subjective matters like these that weight and height (to name but two important measurements) take on their full dimension.

Also, just as chemistry is an important part of a relationship (or encounter), so is the dynamic between subject (e.g., piano) and object (e.g., mic). Not two combinations of individuals coalesce alike, and the same applies to mics and instruments (and vocals).

I'm not saying you're wrong, mind you - simply that I had experiences that may balance (not counter) your opinion

Bruel & Kjaers? I wish!

Interesting stuff. My original reason for being interested in using the measurement mics was to capture an awesome sound source without colouration, presumably the reason they were used on the Bosendorfer you mentioned. I'll have to try a few out to see if it's worth persuing...

Quote Walls:

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...measurement microphones for recording? ... they all have much flatter frequency responses than conventional 'recording' mics.

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Er - NO.

The Sennheiser MKH 20 is ruler flat (see below) with a frequency response from 12Hz to 20kHz (from 5Hz with a simple modification).



This is a neutral transducer with extremely low IM and TH distortion and a very low noise floow.

Measurement microphones do not generally have a low noise floor and are designed for accuracy and consistancy.

If you want neutrality the MKH 20 is, in my opinion, still the best you can get.

Yes - some manufacturers design a microphone to have a "sound" and you will choose that microphone if you want that sound character - the MKH 20, on the other hand, is specifically designed to give you what is there without changing it in any way.

The only other mic. with this philosophy (to my knowledge) is the Earthworks, but the noise floor is higher on the Earthworks.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Fair one. We have some Earthworks mics too. I'll give them a try.
Cheers.

Some of the old B&Ks are certainly fabulous mics, but it is worth bearing in mind that the company ventured from measuring equipment into studio mics as a means of trying to expand their market... and it didn't really work too well whch is why the company eventually hived off the studio mic business to DPA, which has subsequently gone on to develop some outstanding mics, designed from the ground up as studio mics, rather than modified measurement mics.

The B&K (DPA) 4006 omni and 4011 cardioids are very highly regarded mics in the classical recording field, only equalled or bettered (depending on your preferences) by the Sennheiser MKH and Schoeps mics (IMO).

Regarding the Danmarks Radio piano recording, it is no more surprising that B&K mics were used there than it is that BBC radio is still using bucket loads of Coles 4038s. In both cases these are locally produced mics with ideal specifications for the task in hand

hugh

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Technical Editor, Sound On Sound

Quote: "Perhaps you need a state-of-the-art recording studio like DR's, with a Neve Capricorn and a Bosendorfer to make the B&Ks shine, I don't know, but I had a similarly gratifying experience in Paris (with an Ibach, this time), and the results were just as accurate."
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I have a state-of-the-art analogue desk and my own Boesendorfer concert grand and the recording I reffered to above was with a Boesendorfer as well recorded at a studio in Germany.

I get to play with all kinds of mics from all different marques, but I compare them with Neuman 149s and 87s etc. I have just tried out a new range of mics from one manufacturer (sorry, no names here) and they were very good. Almost as good as an 87 or an AKG 414. But almost. Not as good, but almost.

I cannot comment on the new B&K (DPA) mics and I am sure that they are quite good. Back then, B&K mics were almost as good as Schoeps, Neuman or AKGs. But when I record piano, I reach for a 149 or an 87. Back then, it was a 49.

It may just be a question of taste.

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Auf der Oberbaumbrückenschlacht in Berlin geht es jährlich um die Territorialvorrechte. Sei dabei!

I have to say that some of the best piano recordings I have heard were recorded with a pair of B&K 4003's. Maybe it does come down to taste, but a lot of engineers think very highly of the B&K/DPA range and I'm one of them The 4003 in paricular would certainly be my first choice omni for classical recording.

As has been pointed out by others, the logic of "a measurement mic has a flatter response therefore will be better for recording" is flawed. However, I have used and heard measurement mics used to great effect on a wide range of recordings, both pop and classical. Whereas you wouldn't use one in a main pair, they can make fantastic spot mics. For instance, even the behringer measurement microphone (ECM-8000 I believe) which costs around £30 can give spectacular results in a variety of situations.

As with all things in recording, if you understand the "rules" and why they exist, then you shouldn't be afraid to break them. In this case, understand the limitation of the microphones higher noise floor and work around this to get good results.

Regards,

Chris

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Freelance Producer / Engineer | www.hernestudios.co.uk | FREE Listening sessions - see www.thelisteninggroup.org

Quote Bluebottle:

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I have a state-of-the-art analogue desk and my own Boesendorfer concert grand and the recording I reffered to above was with a Boesendorfer as well recorded at a studio in Germany.

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Lucky you!!! I make do with a Yamaha G3 at my project studio...

Quote:

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Almost as good as an 87 or an AKG 414. But almost. Not as good, but almost.

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You use 414s to record your Bosendorfer?

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It may just be a question of taste.

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As I had argued above, but let's face it, the choice of mics also depends on the style of music, the piece played and on the player. Imagine if McCoy Tyner and Martha Argerich were to sit down at the same piano minutes apart...

Quote Bluebottle:

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... But when I record piano, I reach for a 149 or an 87. Back then, it was a 49.

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For a concert grand I would use nothing less than a pure omni.

MKH 20 is my favourite - but there is also the Earthworks, DPA, Schoeps, Neumann KM 130, TLM 50, M50 ...

A directional or switchable mic. just doesn't have the bottom end an omni has.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Well, of course, this is such a huge subject that I for one cannot deal with it in a few short words. And the most intelligent comment was about it depending on the type of music. For example: we used the Boesendorfer for Baroque music and reduced the size (it's a full concert grand with 92 keys) by using two TLM103s. I am experimenting with mics under the sound board to increase the results to almost organ like sounds.

The classical boys want a good clear sound free of colouration. Rock and jazz look for a 'sound' and pop and classic-rock is looking for BIG very often. I can imagine that a test mic could do quite a good job on classical, but I have never tried it, apart from that one time in Bonn in Germany. I do not remember what type they were (it was back in about 1988) but it did not bring out the full size of the piano.

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Auf der Oberbaumbrückenschlacht in Berlin geht es jährlich um die Territorialvorrechte. Sei dabei!

Quote Bluebottle:

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...the most intelligent comment was about it depending on the type of music.

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Agreed.

My comment was a bit tongue-in-cheek, mainly to rub home that a good omni has a full octave in bottom end response better than a directional mic. Most people seem to forget this fact.

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John - Sound-Link ProAudio
President - Federation Internationale des Chasseurs de Sons

Quote: "Almost as good as an 87 or an AKG 414. But almost. Not as good, but almost.
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You use 414s to record your Bosendorfer?"
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No! I was referring to the mics I have been testing. Someone sent me a mic to be tested and reviewed and it was a good mic. Almost as good as a 149 or a 414. But there would have been little point in buying a mic that is almost as good as the ones we have already.

Similarly, I believe that the old B&K mics were very good. Almost as good as the best Schoeps, AKGs and Neumans.

There is also the rather obvious fact that commercial studios (we are one) have to stock equipment that the customer asks for. If the customer asks for Neuman, he or she gets Neuman. As soon as they start asking for DPA, we shall get some.

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Auf der Oberbaumbrückenschlacht in Berlin geht es jährlich um die Territorialvorrechte. Sei dabei!

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For example: we used the Boesendorfer for Baroque music

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Not exactly my choice, whatever mics you use. For the type of music being played that is...

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Expert in non-working solutions