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[James Lugo]

I've had an '86 U87Ai and just acquired a '95 U87Ai. They sound pretty close, the '95 is a hair brighter and has a hair less low end. I ran them both through an A Designs 'Hammer', left the new one alone and boosted about 1.5db at 10k and cut 1db at 200Hz on the old one and ran them tip to tip on a few sources and they sounded almost identical.

Ultimately I want the newer one slightly darkened and maybe give it a slight low end boost. I do not want to touch the '86 if possible.

Can a tech match them? Is there someone in LA that does this?

[Klaus Heyne]

I would start by swapping the heads, and observe whether the specific characteristics you noticed about these mics follow the heads (my guess.)

Then you need to find someone with good ears who can manipulate the capsule performance of the newer K870, and possibly also adjust the older mic's capsule a tad.

[James Lugo]

Thanks Klaus.

[Tim Campbell]

This sounds like it's most likely the capsules.
From the way you describe the difference it would be easy for someone who builds or repairs capsules (not an average mic tech) to match their sound.

[James Lugo]

Thanks Tim. I'm gonna make some calls. I'd love to find someone local in LA. Maybe David Bock does this?

[Fletcher]

I don't believe David is a capsule guy... but Tony Merrill is if you're dead set on a guy from LA.

[J.J. Blair]

Be careful who works on it.  I would personally recommend against having somebody reskin the capsules to achieve a matching sound.  You will likely lose the correct U87 sound all together if that happens.  I would get two capsules from the same production run, and start by using those, then, make whatever adjustments to the electronics of the mic.  

When I rebuilt my M49s to become a matched pair, I got new K47s with consecutive numbers.  I was able to find a side of each capsule that were matched enough that I could use them with each other in cardioid, and consider it a "matched pair."  I also rebuilt the amplifiers, as well.  The mics were two serial numbers apart, and that was what I had to do to achieve that.  I suspect with U87Ais built 9 years apart, there could be a lot of factors that lead to audible differences.  But it will start with the capsules.  

[Arf! Mastering]

As Klaus said, first determine if the difference follows the amp or the capsule.  If the amp is the cause, it can be easily repaired.  If the difference is because of the capusle, this sort of perfectionistic quest can result in the loss of the authentic Neumann sound.  You've got two mics, each with slightly different personalities, but that can easily be made to work as a stereo pair with a little eq.  IMO, leave well enough alone.  A dB or two difference in frequency response is well within the specs of the capsule.

[Silvertone]

While on this subject... does anybody's two ears hear the same?

Not trying to be a wise ass but I've done stereo recordings with two different types of mics at times and have really dug the results (talking drums, not classical work here).

I find because of the way we (most engineers) create stereo mixes that one side always seems to be "the bright side" and one side always seems to be "the dark" side depending on what is panned where.

With all these frequencies floating in the stereo spectrum rarely do the drums sound "the same" (if you will) on each side... so I can tell you as a matter of fact no one has ever said to me, "did you use different mics on the drum overheads" while listening to the stereo mix.  Now, if you solo the overheads that's a different story    but again, sometimes I really like what the two different mics are capturing.

So I tend to agree with Alan here and say use a little EQ and call it a day.

Personally when doing critical stereo recording I always use these U87's modded by this guy named Klaus Heyne... if you can get him to do the work, you'd be all set. (Sometimes it was a modded pair of U67's but 9 times out of 10 I preferred the U87's.)

I'd also recommend Klaus' old right hand man, James Gangwer up in the good old Bay Area...

Good luck James.

[Dino Ziogas]

In the end, there's a standard little test you can do to determine in a practical way if two mics are acceptable as a stereo pair. You can ask for it after you've determined the cause of the discrepancies like the guys suggested.

[Klaus Heyne]

Silvertone wrote on Tue, 01 June 2010 04:13

I'd also recommend Klaus' old right hand man, James Gangwer up in the good old Bay Area...

Just to clarify:
James Gangwer never worked for me, and we have never worked together in any capacity.

During the Brauner Klaus Heyne Edition days, I appointed and recommended him as warranty station, because I had known him for decades as a conscientious individual (AND craftsman.)

James has deep knowledge of high quality professional audio components, including microphones, from his many years as technician for Dan Alexander with whom he is no longer affiliated.

[David Bock]

Quote:

While on this subject... does anybody's two ears hear the same?

Do you mean between the two ears of a person or sets of ears compared between people? Of course they're all identical!
This job is an example of where measurement can be really useful.

Quote:

Not trying to be a wise ass but I've done stereo recordings with two different types of mics at times and have really dug the results (talking drums, not classical work here).

Agreed. Precision matching can be over-rated, and often in the field, mics that are assumed to be matched or stereo are far from it.

[John Monforte]

Don't underestimate stereo matching!

I often used a demo in teaching that had a mono source treated very gently in one channel by any of a number of changes (level, complementary EQ, delay, etc.)

No matter what, the ear latches onto any interchannel difference and tries to ascribe some sort of position information out of it. That's fine when that's what you are after, but if preserving stereo image is important, matching is essential throughout the chain.

As far as these mics are concerned, the fact that two U87a's are made in different years is not an immediate red flag for me. While some might think sequential serial numbers is good enough for matching (I don't), I think there is enough variability in capsules that even an SM69 is not above scrutiny.

Put the mics as close as possible to each other in the far field of a loudspeaker making pink noise. Flip the phase on one and try to cancel the signal out. What is left is what doesn't match. Since the mics are not in the exact same point in space, there will always be a little HF in there. Even in good mics, you will be able to identify some variations. It is worse if they have been out and about for a few years.

Good luck with it!

[Mark Lemaire]

Simply shifting capsule heads from one mic to the other (as Klaus advises) is an excellent start to your project. You'll find how much of the differences are the capsule, how much is the amp. IMO- do NOT go buying new capsules, have your cap reskinned, or any other crazy thing. If you want a REAL stereo pair, you are almost there. If the differences are already subtle, it's detail work you need. You need a capsule guy, as they say.

[Jim Williams]

You may be able to match the mics, but so what? You will never be able to match the acoustics. Those spacing differences will create far larger response variations than any mic to mic differences.

Much ado about nothing. Record some music and don't get so hung up about stuff no one cared about 30 years ago. You know, when the gear was crap but the music was good!