Hello, I'm new to this forum, but have been reading the archives and been impressed with the wealth of knowledge here. I came across a thread discussing the potential problems with diaphrams losing their tension if not glued. I'm just on the verge of purchasing either an MXL v57M (which according to MXL is a 1006), an MXL v67G, or a SP B-1. Do owners of these mics notice any degradation in sound quality over time? Also, this thread seemed to imply that all Studio Projects mics had glued diaphrams, but only the more expensive MXL ones did. Can anyone verify this? Thanks for any help or advice.
Glued Diaphrams on LD mics
- Thread starter Dan DA
- Start date
Harvey Gerst
New member
It's really kind of a non-issue.
What's important is how the back diaphragm is tensioned and how well it will hold it's tension over time. The original Neumann U47s used glued diaphragms that eventually did come loose, although the aging of the PVC was a bigger problem for them.
In either case (glued only, or glued and screwed), you're talking years, not months, before there would be any noticable changes.
In the original thread where this came up, my concern was that the ceramic spacer disk that was screwed on in two places was actually lifted slightly from the back diaphragm, and I didn't know how much SP depended on the spacer for correct tensioning. The final answer was that the spacer wasn't being used for additional tensioning on the C1, so it really was a non-issue.
Where the fireworks came in was that Alan thought I was accusing SP of short-changing customers by not using all the screws, but we eventually got it all straightened out.
The "Under The Hood" thread:
https://homerecording.com/bbs//showthread.php?s=&threadid=28989
actually makes for some good reading and a pretty good insight into mic manufacturing and design, if you can get past my temper-tantrum and Alan's yelling.
What's important is how the back diaphragm is tensioned and how well it will hold it's tension over time. The original Neumann U47s used glued diaphragms that eventually did come loose, although the aging of the PVC was a bigger problem for them.
In either case (glued only, or glued and screwed), you're talking years, not months, before there would be any noticable changes.
In the original thread where this came up, my concern was that the ceramic spacer disk that was screwed on in two places was actually lifted slightly from the back diaphragm, and I didn't know how much SP depended on the spacer for correct tensioning. The final answer was that the spacer wasn't being used for additional tensioning on the C1, so it really was a non-issue.
Where the fireworks came in was that Alan thought I was accusing SP of short-changing customers by not using all the screws, but we eventually got it all straightened out.
The "Under The Hood" thread:
https://homerecording.com/bbs//showthread.php?s=&threadid=28989
actually makes for some good reading and a pretty good insight into mic manufacturing and design, if you can get past my temper-tantrum and Alan's yelling.
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Harvey, thank you for the https://homerecording.com/bbs//showt...&threadid=28989 link. That was a long read, not as long or as good as the "Big Thread" but still good, and it did answer my question about the glue/bond and etc. Oh, and again I'm sorry about the plastic crap mistake I made, please don't hold that against me.
Brent Casey
Just add water and stir!
Harvey,
I'm having trouble visualizing what you are saying here regarding the rear diaphragm, tensioning, spacers etc. For example, the spacers on the Studio Projects mics are not ceramic, they are steel. Also, I agree about the need for the rear diaphagm to be of proper tension, but what of the front diaphragm tension? Would you consider this to be "kind of a non-issue" as well?
As for your comparison of "glued vs. glued and screwed" This is not what I am speaking of. My point is regarding all diaphragm material, both front and back and my comparison is "glued vs not glued".
The original Neumann M7 capsule, (also known as today's Gefell M7 capsule with better glue) as well as any small diaphragm mic of today uses a bonding agent of some sort to mount the diaphragm to the capsule, or clamping ring. The reason for this, as I have previously stated, is to achieve a complete and long-term edge attachment of the tensioned diaphragm material. Also, as previously stated, the practice of mounting the MOVABLE membrane to the rest of the capsule without employing any bonding element whatsoever is unique to the "various models" of large-diaphragm microphones being manufactured in Shanghai, as far as I know.
While I agree with your assessment that it will generally be years - not months in which a "glued- or -glued/screwed" diaphragm should begin to show noticeable changes in performance, I happen to know from my own research and experimentation that a large diaphragm capsule that is NOT glued will exhibit demonstrable changes within months, usually much less, if exposed to wider variations in temperature and pressure. Additionally, these capsules generally have existing factory tensioning problems of varying severity due to the fact that edge glueing is not employed - among other factors. These initial problems simply become magnified on top of which further innacuracies are inherently likely to appear.
Imagine for a moment if you will, the sun-bleached skull of a bull sitting in the desert. We pick it up, remove the horns and in their place, mount two large-diaphragm microphones - one with a glued/screwed diaphragm, and one where the capsule membrane is mounted by being sandwiched between two surfaces which are held together by screws. Say we then mount the cow skull on the front grill of a 1974 Dodge Ram pickup and proceed to drive for a distance of 1200 feet at a rate of twenty miles per hour or so. At the end of the 1200 feet, there is a concert hall where you are to deliver one of the microphones for a Very Important Performance, downbeat: three minutes. Knowing what you know about the aforementioned elements of capsule construction, which mic are you most likely to select from the cow skull mount? Well, it may depend on what the Very Important Performance consists of. Ok: the mic is going to be used inside a kick drum. What's it going to be?
Although this is a rather bizarre and non-scientific thought experiment, it may help to illustrate (in a brute force manner) that a crucial step in the assembly of capacitor microphones such as edge gluing the diaphragms should perhaps be ranked slightly higher than that of "kind of a non-issue". This isn't a boxers/briefs, or a suspenders with a belt issue. It is a matter of good manufacturing techniques vs. inferior ones and I defy anyone to prove to me that this is not so. I already know that it doesn't take a Dodge Ram and a 20mph breeze to bring about a change in something manufactured to inherently minute tolerances, relatively speaking.
Lastly, I went back and took a look at much of the "under the hood" thread and no offense to any parties involved (myself included), I would not describe it as a "pretty good insight into mic manufacturing and design", although it is pretty entertaining on the whole.
Sincerely,
Brent Casey
Studio Projects Microphones
877-563-6335
I'm having trouble visualizing what you are saying here regarding the rear diaphragm, tensioning, spacers etc. For example, the spacers on the Studio Projects mics are not ceramic, they are steel. Also, I agree about the need for the rear diaphagm to be of proper tension, but what of the front diaphragm tension? Would you consider this to be "kind of a non-issue" as well?
As for your comparison of "glued vs. glued and screwed" This is not what I am speaking of. My point is regarding all diaphragm material, both front and back and my comparison is "glued vs not glued".
The original Neumann M7 capsule, (also known as today's Gefell M7 capsule with better glue) as well as any small diaphragm mic of today uses a bonding agent of some sort to mount the diaphragm to the capsule, or clamping ring. The reason for this, as I have previously stated, is to achieve a complete and long-term edge attachment of the tensioned diaphragm material. Also, as previously stated, the practice of mounting the MOVABLE membrane to the rest of the capsule without employing any bonding element whatsoever is unique to the "various models" of large-diaphragm microphones being manufactured in Shanghai, as far as I know.
While I agree with your assessment that it will generally be years - not months in which a "glued- or -glued/screwed" diaphragm should begin to show noticeable changes in performance, I happen to know from my own research and experimentation that a large diaphragm capsule that is NOT glued will exhibit demonstrable changes within months, usually much less, if exposed to wider variations in temperature and pressure. Additionally, these capsules generally have existing factory tensioning problems of varying severity due to the fact that edge glueing is not employed - among other factors. These initial problems simply become magnified on top of which further innacuracies are inherently likely to appear.
Imagine for a moment if you will, the sun-bleached skull of a bull sitting in the desert. We pick it up, remove the horns and in their place, mount two large-diaphragm microphones - one with a glued/screwed diaphragm, and one where the capsule membrane is mounted by being sandwiched between two surfaces which are held together by screws. Say we then mount the cow skull on the front grill of a 1974 Dodge Ram pickup and proceed to drive for a distance of 1200 feet at a rate of twenty miles per hour or so. At the end of the 1200 feet, there is a concert hall where you are to deliver one of the microphones for a Very Important Performance, downbeat: three minutes. Knowing what you know about the aforementioned elements of capsule construction, which mic are you most likely to select from the cow skull mount? Well, it may depend on what the Very Important Performance consists of. Ok: the mic is going to be used inside a kick drum. What's it going to be?
Although this is a rather bizarre and non-scientific thought experiment, it may help to illustrate (in a brute force manner) that a crucial step in the assembly of capacitor microphones such as edge gluing the diaphragms should perhaps be ranked slightly higher than that of "kind of a non-issue". This isn't a boxers/briefs, or a suspenders with a belt issue. It is a matter of good manufacturing techniques vs. inferior ones and I defy anyone to prove to me that this is not so. I already know that it doesn't take a Dodge Ram and a 20mph breeze to bring about a change in something manufactured to inherently minute tolerances, relatively speaking.
Lastly, I went back and took a look at much of the "under the hood" thread and no offense to any parties involved (myself included), I would not describe it as a "pretty good insight into mic manufacturing and design", although it is pretty entertaining on the whole.
Sincerely,
Brent Casey
Studio Projects Microphones
877-563-6335
Harvey Gerst said:It's really kind of a non-issue.
What's important is how the back diaphragm is tensioned and how well it will hold it's tension over time. The original Neumann U47s used glued diaphragms that eventually did come loose, although the aging of the PVC was a bigger problem for them.
In either case (glued only, or glued and screwed), you're talking years, not months, before there would be any noticable changes.
In the original thread where this came up, my concern was that the ceramic spacer disk that was screwed on in two places was actually lifted slightly from the back diaphragm, and I didn't know how much SP depended on the spacer for correct tensioning. The final answer was that the spacer wasn't being used for additional tensioning on the C1, so it really was a non-issue.
Where the fireworks came in was that Alan thought I was accusing SP of short-changing customers by not using all the screws, but we eventually got it all straightened out.
The "Under The Hood" thread:
https://homerecording.com/bbs//showthread.php?s=&threadid=28989
actually makes for some good reading and a pretty good insight into mic manufacturing and design, if you can get past my temper-tantrum and Alan's yelling.
Brent Casey
Just add water and stir!
Nope, that's fine.
Brent
Brent
DJL said:
Flatpicker
...
LOL!Brent Casey said:
That's almost as funny as the swirling chours effect you got from playing your guitar in the ocean...
Harvey Gerst
New member
Brent Casey said:
Well, Alan got a little part of it wrong too, in that he said the back diaphragm doesn't contribute to the sound; it was there basically as a dust cover. You, of course, know better, as you stated above in your first paragraph.
The thread probably wouldn't be of any use to you or Stephen Paul, but it seemed to help a lot of people here to understand a little more about how mics work.
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Harvey Gerst
New member
P.S.,
Brent, I did love the imagery you conjured up.
Brent, I did love the imagery you conjured up.
Brent Casey
Just add water and stir!
I think we're talking past each other here at the very least, Harvey.
Can you show me a V67 diaphragm that is glued and clamped as you say here below? I all but begged the upstairs crowd there for years to glue and clamp the diaphragms, but they maintained the opinion that it was a non-issue (and not cost effective).
Regards,
Brent Casey
Studio Projects Microphones
877-563-6335
Apples and oranges, Brent. The non issue I spoke of was only in reference to the difference between glueing only (as in the rear diaphragm of a C1), versus glueing AND clamping (as in the rear diaphragm of a V67).
Can you show me a V67 diaphragm that is glued and clamped as you say here below? I all but begged the upstairs crowd there for years to glue and clamp the diaphragms, but they maintained the opinion that it was a non-issue (and not cost effective).
Regards,
Brent Casey
Studio Projects Microphones
877-563-6335
Apples and oranges, Brent. The non issue I spoke of was only in reference to the difference between glueing only (as in the rear diaphragm of a C1), versus glueing AND clamping (as in the rear diaphragm of a V67).
Son of Mixerman
Mix Junior
Hey, can you guys post some pictures somewhere that goes through the manufacturing process step by step in generic way as not to reveal proprietary information. This thread and the other one referenced here where Stephen Paul really intrigued me. Im designer who deals mainly with military electronics and have to trade studies occasionaly to justify costs and schedule problems. My biggest curiosity is tensioning the diaphragms. Assuming that these diaphragms are mylar for a majority of the mic's mentioned, I wonder alot about shear strength, elongation and thermal differentials being variables that are tough to control, especially when were talking about ones only slightly thicker than air itself.
SoMm
SoMm
Harvey Gerst
New member
Brent Casey said:
Brent,
Ahhh, now we're getting some place. There was definitely some misunderstanding here. I was not aware that the V67 is only clamped, not glued and clamped. That does change things somewhat. See why this forum needs you? It's an interesting question.
I REALLY like the sound of my V67Gs a lot (as you well know) and I don't think clamping only will cause catastrophic sound changes in a reasonably stable studio environment, but I'll have to wait till I get mine back from Stephen Paul to see if their 18 month stay there has caused any significant response changes.
Thank you for clearing the air about the V67 assembly techniques. Your long explanation makes a lot more sense now that I understand the differences we were cross-discussing.
Brent Casey
Just add water and stir!
Yes, a LLLRRRHEWM sir, that is what I have been saying. I would like a lllrhoom.
http://www.filmnight.org/images/clouseau.jpg
http://www.filmnight.org/images/clouseau.jpg
Harvey Gerst said:
The thread probably wouldn't be of any use to you or Stephen Paul, but it seemed to help a lot of people here to understand a little more about how mics work.
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I learned from reading that thread, and this thread has good stuff in it also.
I think I understand it would be better it they were glued, sandwiched, and bolted using all the bolts.
How do I maintain a reasonably stable studio environment? I can control the temperature, and humidity, but how do I control the barometric pressure in my studio? And I think it was said somewhere in the threads the changes in pressure over a (short/long?) time will reck the mic. How, much time are we talking about, months, years, how many years?
Brent, are these Marshall and Studio Projects microphones like a time bomb, just waiting to change into a door stop? I hope not, I have a lot of them.
Thanks
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I learned from reading that thread, and this thread has good stuff in it also.
I think I understand it would be better it they were glued, sandwiched, and bolted using all the bolts.
How do I maintain a reasonably stable studio environment? I can control the temperature, and humidity, but how do I control the barometric pressure in my studio? And I think it was said somewhere in the threads the changes in pressure over a (short/long?) time will reck the mic. How, much time are we talking about, months, years, how many years?
Brent, are these Marshall and Studio Projects microphones like a time bomb, just waiting to change into a door stop? I hope not, I have a lot of them.
Thanks
Son of Mixerman
Mix Junior
Heheh...Yeah.... Im at sea level, is the performance going to suffer because of increased air density! Maybe thats why Im a little slow!
SoMm
SoMm