Topic: DPA High boost grid vs soft boost grid

[divamum]

divanum, The grids are pretty snug on there. You just pull them off, but try to hold the capsule body and not pull too hard on the cable.  Difficult I know since they're so small and tapered.

Oh, I'd Never pull on the cable!

I've never taken them off but assumed I'd do it this way...  Gently hold the body with a pair of needle nose pliers and then lever the grid up a bit at a time with a small screwdriver, wedging against the pliers?

Just a friendly bit of advice never use pliers on the body of an electret or any other condenser microphone. You could cause a distortion in the mic housing and damage the capsule forever.. That mic must never be subjected to any force on the body other then holding it to remove the cap with your hands only..

Chris
 

Good grief - I was afraid even to pull them too hard with my fingers so I'd never consider using a pair of pliers! 

For the time being, they can stay as shipped; once I have a little more time I'll sit down in some good light and see what I can do!

Thanks, boys, as ever - have I mentioned recently how much I love TS?  I am SO busy at the moment that I've had little time to read at length and/or run tests with this new gear, so being able to ask a question (however dufus a one) and get a kind, clear and exactly-what-I-needed-when-I-needed it answer in time to USE the new stuff properly is HUGELY appreciated! 

[Church-Audio]

Pliers are merely a tool.. Whether you crush something with them is another discussion entirely. You need to use the right kind of plier.  My fingers cannot grasp the body of the mic effectively so I would use a tool.

If you crush the mic housing you will damage the mic.. And the neat thing is you might not even notice it but any distortion on the electret mic housing will result in a "stretching or distortion of the mics diaphragm" this will have a direct and dire consequences to the mics performance. Even with the " right " set of pliers I would never use a tool to take the cap off. You can if you have big fingers use the rubber finger condoms they work great and give you good grip over the mic cap.. Allowing you to take if off with a minimal pressure. I am sure you have fine motor skills with your hands like I do.. But Its just not worth the risk IMO.

Chris

[Gutbucket]

The capsule in my 4090 is a 4060 capsule with a flat frequency response correction grill added.. And they epoxied it on Smart little fellas at DPA I think this capsule is subjected to a few more tests then the regular 4060 but its the same capsule. This grill to my knowledge is not available for resale. But I have not contacted DPA to find that out.

Chris

Sure would be nice for them to make those available. 

It seems one could shorten a standard grid somewhat more to lessen the boost and make it flat, retaining the ~14khz response and polar pattern.  The tough part would be figuring exactly how much to trim it.  File it down until it's response matches a 4090 (or other flat 'measurement' mic) I guess.  Do you think the metal grill part of the grid has any effect other than protecting the capsule, or is it just the tube length that is effecting the response?

Hey boys and girls, here's a fun experiment to hear this effect in action: fire up your mics and monitor through some closed or in-ear phones (to eliminate potential feedback), then hold the capsule and form a little tube with your hand or fingers.  The tube doesn't have to be round.  Squeeze the opening down to a tiny hole.  By changing the volume inside the 'tube' you can easily hear the exaggerated HF boost and the relationship between the size of the opening (or is it the volume of the tube?) and the frequency of the boost.   

[Church-Audio]

The capsule in my 4090 is a 4060 capsule with a flat frequency response correction grill added.. And they epoxied it on Smart little fellas at DPA I think this capsule is subjected to a few more tests then the regular 4060 but its the same capsule. This grill to my knowledge is not available for resale. But I have not contacted DPA to find that out.

Chris

Sure would be nice for them to make those available. 

It seems one could shorten a standard grid somewhat more to lessen the boost and make it flat, retaining the ~14khz response and polar pattern.  The tough part would be figuring exactly how much to trim it.  File it down until it's response matches a 4090 (or other flat 'measurement' mic) I guess.  Do you think the metal grill part of the grid has any effect other than protecting the capsule, or is it just the tube length that is effecting the response?

Hey boys and girls, here's a fun experiment to hear this effect in action: fire up your mics and monitor through some closed or in-ear phones (to eliminate potential feedback), then hold the capsule and form a little tube with your hand or fingers.  The tube doesn't have to be round.  Squeeze the opening down to a tiny hole.  By changing the volume inside the 'tube' you can easily hear the exaggerated HF boost and the relationship between the size of the opening (or is it the volume of the tube?) and the frequency of the boost.   

The metal grill is acoustically transparent. Its absolutely the length of the plastic tube that determines the frequency response. If you really want to try and figure it out buy some brass tube from a hobby store and play around with the length of it until you can see the difference in a program the trick is to use a RTA with a good tweeter.

Chris

[Gutbucket]

Yup, I too was thinking hobby store brass tubing. 

[edit] can you determine how long (or short, rather) the grid tube is on your 4090?

[Church-Audio]

Yup, I was thinking hobby store brass tubing. 

It works great but! you have to make sure you get the exact size of the cap or it will be moot..

Chris..

[Gutbucket]

It works great but! you have to make sure you get the exact size of the cap or it will be moot..

Right size diameter you mean? Can you determine how long the grid tube on your 4090 is?

[Church-Audio]

It works great but! you have to make sure you get the exact size of the cap or it will be moot..

Ok the length of the tube from base to top where the screen starts is 0.1635 inches the Diameter is 0.215 inches. The other issue is the fact that the cap is very thin so you must make your inside diameter be the same as your caps inside diameter or this will not work...

Chris

[Gutbucket]

[quote author=Church-Audio link=topic=59502.msg1114945#msg1114945
Ok the length of the tube from base to top where the screen starts is 0.1635 inches the Diameter is 0.215 inches. The other issue is the fact that the cap is very thin so you must make your inside diameter be the same as your caps inside diameter or this will not work...

Chris
[/quote]

Cool, this is now on my extensive list of potential projects. Someday I'll give it a whirl.

Thanks Chris,
Lee