Best affordable U47 Body?

[Cqwet Dbdfte]

Matching of capsules would involve an anechoic chamber, a broad band noise source driving s speaker, then making sure both mike elements are in phase, , and magnitude, then reversing the phase on one and looking for complete signal cancellation.

 

[soliloqueen]

Matching of capsules would involve an anechoic chamber, a broad band noise source driving s speaker, then making sure both mike elements are in phase, , and magnitude, then reversing the phase on one and looking for complete signal cancellation.

That's wildly overcomplicated and introduces tons of needless points of failure. This is probably the least efficient and most error-prone way to do this. You only need 2 sine wave sweeps with each capsule in the same exact location in a room with reasonable acoustics to match 2 capsules if you know they have the same anatomy. Since you're only matching capsules, you don't need any absolute reference, only the difference between the two.

 

[Tim Campbell]

Matching of capsules would involve an anechoic chamber, a broad band noise source driving s speaker, then making sure both mike elements are in phase, , and magnitude, then reversing the phase on one and looking for complete signal cancellation.

No company matches capsules this way. It would be too expensive and unecessary. Measuring output and freq. response is quite enough. Matched capsules are usually selected from large batches that have been individually measured beforehand. In any group of capsules there will always be some pairs that match perfectly.
My own capsule generally vary less than a half dB en masse.

 

[jcarthur]

That's wildly overcomplicated and introduces tons of needless points of failure. This is probably the least efficient and most error-prone way to do this. You only need 2 sine wave sweeps with each capsule in the same exact location in a room with reasonable acoustics to match 2 capsules if you know they have the same anatomy. Since you're only matching capsules, you don't need any absolute reference, only the difference between the two.

Hi Arienne, I was planning on using two of your flat K47s in these builds. Are you able to supply a matched pair if I order two at once? Thanks!

Best,
John

 

[soliloqueen]

Hi Arienne, I was planning on using two of your flat K47s in these builds. Are you able to supply a matched pair if I order two at once? Thanks!

Best,
John

I should be able to match sensitivity for you

 

[Cqwet Dbdfte]

No company matches capsules this way. It would be too expensive and unecessary. Measuring output and freq. response is quite enough. Matched capsules are usually selected from large batches that have been individually measured beforehand. In any group of capsules there will always be some pairs that match perfectly.
My own capsule generally vary less than a half dB en masse.

"Matching" is matching, and should produce some numerical output describing how close the match is. What number is good enough? My method has been described elsewhere.

 

[Tim Campbell]

"Matching" is matching, and should produce some numerical output describing how close the match is. What number is good enough? My method has been described elsewhere.

I am not saying your method won't produce correct results. I am just saying that only a "one off" or private individual would got to that extent for a microphone used for music. Brüel og Kjær certainly used a similar method for testing random capsules or if required but measuring every pair of capsules out of 1000s of capsules that have already been measured individually would not be cost effective and the difference in results would be negligible if any.

The main difference you describe would be measuring 2 capsules at the same time and nulling them. When taking freq. responce graphs the signals are already laid in top of each other showing variations in freq. and output. The other steps are redundant.

 

[Cqwet Dbdfte]

I can't imagine what a production setup would look like that would produce uniform tension in membranes.
Is vacuum sputtering done post stretching?
Is the whole surface active in producing output, has any finite element analysis been done to optimise sputter masking? Mechanically inactive areas may not need to be metallised?

 

[Tim Campbell]

I can't imagine what a production setup would look like that would produce uniform tension in membranes.
Is vacuum sputtering done post stretching?
Is the whole surface active in producing output, has any finite element analysis been done to optimise sputter masking? Mechanically inactive areas may not need to be metallised?

 

[Cqwet Dbdfte]

Nice, high vacuum pumped? Cryo, turbo?
Looks like membranes are not stretched?

 

[Tim Campbell]

Every manufacturer does this process differently. I was taught by AKG so I use their method. The membranes are tuned on a separate jig afterwards. Many sputter at slightly lowered tension and then tune up at assembly.

 

[soliloqueen]

Mechanically inactive areas may not need to be metallised?

Other points aside for a moment, I've never seen this done but I've been thinking about this exact thing for the past couple weeks. You don't need FEA as the math for how the membrane moves is fairly simple. I would love to try this. It would be as simple as calculating travel over the membrane for every location for every frequency and then making a final 2d map by averaging all the audible frequencies and sputtering that map.

 

[Tim Campbell]

Other points aside for a moment, I've never seen this done but I've been thinking about this exact thing for the past couple weeks. You don't need FEA as the math for how the membrane moves is fairly simple. I would love to try this. It would be as simple as calculating travel over the membrane for every location for every frequency and then making a final 2d map by averaging all the audible frequencies and sputtering that map.

I have done this quite a long time ago but it doesn't present itself that linearly. There are so many other factors working simultaneously in a capsule and some aspects of freq. can be attained in more than one way.

The membrane moves like a drop in water not like a piston. I have a plot of this somewhere from an AKG white paper

 

[soliloqueen]

I have done this quite a long time ago but it doesn't present itself that linearly. There are so many other factors working simultaneously in a capsule and some aspects of freq. can be attained in more than one way.

The membrane moves like a drop in water not like a piston. I have a plot of this somewhere from an AKG white paper

I know how the membrane moves. It's pretty interesting!

 

[jcarthur]

I should be able to match sensitivity for you

Thank you, I will email you now to organise a pre order.