Why you should never use multi pattern mics

[Marik]

Just to be clear about "phasing issues" I mentioned in the op. I am talking about introducing signal coming from rear diaphragm which is separated by the thickness of the backplate from the front one. So there is slight delay, although small it falls in the audible range.

Not only the thickness of the backplate, but also distance difference formed by external/internal passages between front signal and backwave reaching rear of the diaphragm. This distance can be pretty long. Depending on the parameters of the passage it can introduce an obstacle for lower frequencies, so the entire system is also frequency dependent. In reality the phase anomalies are all over the place, but (as already was mentioned) that's how we form the cardioid pattern in this type of the capsule.

There are ways to reduce those anomalies. One of them is optimization of the passage parameters using vented 3 chamber design (obviously, it comes to agreement with the very title of this thread). Another is using mass controlled system and introducing infinite back load with some backwave leak. The third is combining two native patterns--fig 8 and true pressure omni instead of using resistance controlled system, which by definition has intrinsic deficiencies to start with.

Best, M

 

[kingkorg]

Not only the thickness of the backplate, but also distance difference formed by external/internal passages between front signal and backwave reaching rear of the diaphragm. This distance can be pretty long. Depending on the parameters of the passage it can introduce an obstacle for lower frequencies, so the entire system is also frequency dependent. In reality the phase anomalies are all over the place, but (as already was mentioned) that's how we form the cardioid pattern in this type of the capsule.

There are ways to reduce those anomalies. One of them is optimization of the passage parameters using vented 3 chamber design (obviously, it comes to agreement with the very title of this thread). Another is using mass controlled system and introducing infinite back load with some backwave leak. The third is combining two native patterns--fig 8 and true pressure omni instead of using resistance controlled system, which by definition has intrinsic problems to start with.

Best, M

Awesome, thanks!

 

[Mark mth001]

Not only the thickness of the backplate, but also distance difference formed by external/internal passages between front signal and backwave reaching rear of the diaphragm. This distance can be pretty long. Depending on the parameters of the passage it can introduce an obstacle for lower frequencies, so the entire system is also frequency dependent. In reality the phase anomalies are all over the place, but (as already was mentioned) that's how we form the cardioid pattern in this type of the capsule.

There are ways to reduce those anomalies. One of them is optimization of the passage parameters using vented 3 chamber design (obviously, it comes to agreement with the very title of this thread). Another is using mass controlled system and introducing infinite back load with some backwave leak. The third is combining two native patterns--fig 8 and true pressure omni instead of using resistance controlled system, which by definition has intrinsic problems to start with.

Best, M

Not only the thickness of the backplate, but also distance difference formed by external/internal passages between front signal and backwave reaching rear of the diaphragm. This distance can be pretty long. Depending on the parameters of the passage it can introduce an obstacle for lower frequencies, so the entire system is also frequency dependent. In reality the phase anomalies are all over the place, but (as already was mentioned) that's how we form the cardioid pattern in this type of the capsule.

There are ways to reduce those anomalies. One of them is optimization of the passage parameters using vented 3 chamber design (obviously, it comes to agreement with the very title of this thread). Another is using mass controlled system and introducing infinite back load with some backwave leak. The third is combining two native patterns--fig 8 and true pressure omni instead of using resistance controlled system, which by definition has intrinsic problems to start with.

Best, M

That third option was used in the STC4033, a 1940s mic which had a ribbon and omni in the same body. You could choose between the three patterns - fig 8, omni. cardi. The STC 4033A

 

[ricardo]

makes me want to design a capsule that has intakes for the rear at almost the same place as the front diaphragm, routes it around the back and then back to the front.

The Calrec SDC cardioid is MUCH simpler than the AKG SDCs. IMnotsoHO, the Calrec stick cardioid is still one of the best SDC cardioids. What Clem Beaumont realised is that the 'mounting in the stick' has just as much effect as certain capsule intricacies and much easier to tweak. One of the parameters is the position of the slots/holes. If you have wonky back response, try moving them forward.