Why you should never use multi pattern mics

GroupDIY Audio Forum

Help Support GroupDIY Audio Forum:

k brown

Well-known member
Joined
Jul 7, 2021
Messages
410
Location
San Francisco
Josephson C700A:


Though uses a fig8 condenser, not a ribbon.

I've often wondered why Royer has never done a mic with a small omni condenser on top of a ribbon. Especially since they're already stuffing electronics inside some of their ribbon mics.
 

Attachments

  • c700a.png
    c700a.png
    106.2 KB · Views: 0

emrr

Well-known member
Joined
Apr 12, 2006
Messages
8,211
Location
NC, USA
I dunno, the MKH 30 seems to have a better figure 8 pattern and response than anything else I’ve ever used.


I’ll just put this here, think i mentioned it earlier.


52184589554_7bace21902_c.jpg
 

Marik

Well-known member
Joined
Jun 3, 2004
Messages
1,674
Location
Salt Lake City
Excellent post!

A follow-up question, if I may: the old Western Electric/Altec 639b achieved its directional pattern by combining a pressure omni moving-coil and a bidirectional ribbon, each in their native pattern, summed to create cardioid.

What would be the advantages/disadvantages to reimagining this fundamental principle in a more-modern design? Perhaps a pressure condenser combined with a ribbon, selected/designed to have very similar bandwidth characteristics.

Obviously the two elements could not exist in the same physical space which may present a trade-off. Are there other reasons this would be inadvisable?

Funny you asked this question--we just announced such mic--Samar AF08 at the last NAMM a couple months ago--the concept I've been working since 2004. It uses a fig8 ribbon and true pressure omni capsule, which not only helps to create cardioid pattern, but also 'fills' the very top and very bottom of the bandwidth. The sonics are quite remarkable--very precise, but also very relaxed and natural (as one could expect). No any deficiencies of regular LDC, such as rugged top with usual HF peak, poor off axis, poor rear lobe cancellation, which is also frequency dependent, etc.

The WE/Altec were good mics for the time, but limited by the use of dynamic omni element, which had low sensitivity, rather poor response and did not match its ribbon counterpart well. Also, it is not a true pressure element, but rather acoustical resistance controlled. Obviously, modern Neodymium magnets and condenser pressure omnies give by far superior results.

The early (cardioid only) RCA 77A's and B's in my view were more successful than WE/Altec. They used a ribbon divided in half, where one half was fig8 and another was loaded through a coupler to labyrinth to form an infinite acoustic load for omni pattern. Since both halves shared the same ribbon the both signals were mixed in a natural way and did not require any additional transformer taps. Their main problem was also with omni part where the corners in labyrinth passages did not work exactly like a straight tube and were not exactly introducing an infinite load for correct work.

Best, M
 
Last edited:

Murdock

Well-known member
Joined
Jan 28, 2015
Messages
657
Location
Germany
Excellent post!

A follow-up question, if I may: the old Western Electric/Altec 639b achieved its directional pattern by combining a pressure omni moving-coil and a bidirectional ribbon, each in their native pattern, summed to create cardioid.

What would be the advantages/disadvantages to reimagining this fundamental principle in a more-modern design? Perhaps a pressure condenser combined with a ribbon, selected/designed to have very similar bandwidth characteristics.

Obviously the two elements could not exist in the same physical space which may present a trade-off. Are there other reasons this would be inadvisable?
Pretty surprised that no one did it before as I just had the idea a few weeks ago. But I thought there is a reason no one did it before... would also be interested in the possible problems of such a system. How about combining the two? I would think level and impedance wise it is quite difficult to combine these two systems. Would one rather have two separate amplifier and combining them at the output or is it possible to combine them right at the capsules?

Interestingly Schoeps developed the CM51/3 in the 50s which also had a pressure Omni and sdc fig 8 which you could „add“ to the Omni by a switch inside the head to get a cardioid.
 

Marik

Well-known member
Joined
Jun 3, 2004
Messages
1,674
Location
Salt Lake City
Interestingly Schoeps developed the CM51/3 in the 50s which also had a pressure Omni and sdc fig 8 which you could „add“ to the Omni by a switch inside the head to get a cardioid.

The only Schoeps with 3 pattern capsule I can remember is M221B with MK26 capsule. From memory the CM51/3, CM51, and M201 (aka Telefunken ELAM 201) could use omni/cardioid capsules, only (like M934B, C). All of those had ingenious mechanical shutter system to load the diaphragm with correct acoustical resistance, and polar pattern air passages. Important to notice, the MK26 never became quite successful, as the best it worked in fig8 pattern. Its omni and cardioid patterns were outperformed by the single, more optimized capsules.

Best, M
 

Murdock

Well-known member
Joined
Jan 28, 2015
Messages
657
Location
Germany
The only Schoeps with 3 pattern capsule I can remember is M221B with MK26 capsule. From memory the CM51/3, CM51, and M201 (aka Telefunken ELAM 201) could use omni/cardioid capsules, only (like M934B, C). All of those had ingenious mechanical shutter system to load the diaphragm with correct acoustical resistance, and polar pattern air passages. Important to notice, the MK26 never became quite successful, as the best it worked in fig8 pattern. Its omni and cardioid patterns were outperformed by the single, more optimized capsules.

Best, M
When you google „Schoeps CM51/3“ there is a link to the Schoeps history site. It’s in German but there it is written that it had system with two capsules inside (fig. 8 and Omni). The head looks like the newer V4U which is based on the CM51/3 (the design that is).
Also you can see the two capsules on some images on the net. Note, that there is also the M201 which had a similiar head but only one small cardioid capsule with a ring around it to mimic some of the LDC properties.
 

Marik

Well-known member
Joined
Jun 3, 2004
Messages
1,674
Location
Salt Lake City
When you google „Schoeps CM51/3“ there is a link to the Schoeps history site. It’s in German but there it is written that it had system with two capsules inside (fig. 8 and Omni). The head looks like the newer V4U which is based on the CM51/3 (the design that is).
Also you can see the two capsules on some images on the net. Note, that there is also the M201 which had a similiar head but only one small cardioid capsule with a ring around it to mimic some of the LDC properties.
I see! There is history site in English as well:


There the one you describe is under M201.

Best, M
 

Newmarket

Well-known member
Joined
Oct 10, 2016
Messages
1,338
Location
Brighton Sussex UK
Interesting stuff here for someone who is not experienced in microphone details but who has expertise in solid state electronics.
Not wanting to sound a sour note wrt the OP but it strikes me that the term "should never" in the thread title is somewhat ill advised ?
 

kingkorg

Well-known member
GDIY Supporter
Joined
Apr 15, 2017
Messages
1,860
Location
Norway
Interesting stuff here for someone who is not experienced in microphone details but who has expertise in solid state electronics.
Not wanting to sound a sour note wrt the OP but it strikes me that the term "should never" in the thread title is somewhat ill advised ?
I admit it's a bit click bity, but there is a disclaimer in the first post. For my part, unless i'm not forced to use them for whatever reason, i absolutely dont!

The topic is quite complicated, and we haven't really gone into the issues with electronics where in many topologies these paterns don't even work as advertised. Yes you hear the sound coming from both sides, but what you get is nether F8, nor omni. Cardioid is also questionable, hence the craze for the "true cardioid" topology.

I would be very interested how you achieved the combination of ribbon and condenser elements. Without giving any of your secrets of course.
Active ribbon?
 

soliloqueen

Well-known member
GDIY Supporter
Joined
Oct 5, 2020
Messages
332
Something I was thinking about reading this thread: "Ribbon" is just a shape, not necessarily an operating principle. You can make an electrostatic ("condenser") ribbon capsule, and you can also make a planar magnetic capsule. They're just both not tremendously useful for recording audio. Planar magnetic drivers, which have the operating mechanism of ribbon drivers but the plate construction of electrostatic drivers, are used in headphones sometimes, but I've never seen one used as a capsule. I've never seen an electrostatic ribbon used for anything, even though it's technically possible.
 
Last edited:

k brown

Well-known member
Joined
Jul 7, 2021
Messages
410
Location
San Francisco
Bought one of those things on ebay many years ago; couldn't figure what the heck to do with it - the element looked like a solid slab of beeswax. Also reeked of cigarette smoke. No info online at all about it at the time - threw it away.
 
Last edited:

emrr

Well-known member
Joined
Apr 12, 2006
Messages
8,211
Location
NC, USA
Every Velotron I've seen had all the ribbons broken. I think Xaudia messed with one somewhat recently.
 
Top