Superlux S502 MK2 test, teardown and improvements

[k brown]

??

"Diffuse Field" and "Free Field" are entirely about distance.

 

[molke]

Maybe, “free field” means “plane wave field”, so, for example, very large distance in free field conditions. With an established manufacturer, I would hope for a standard measurement distance of 1 m of published graphs if nothing is explicitly stated (I think the Line Audio graphs are exemplary in this regard). Here is a quick simulation for a 22 mm cardioid at different distances (based on the formulas given in the Shure paper). I still don’t understand enough to say whether the chosen lumped parameters are realistic.
For a figure 8 microphone, the effect is even more pronounced. See e.g. the quotes of Jörg Wuttke regarding the low-frequency response of a Schoeps MK8 and the lengths they go through in development to get the ‘real’ response.

 

[k brown]

https://sengpielaudio.com/DirectFieldAndReverberantField.pdf

 

[ubxf]

I know of only 2 SDC cardioids which are -3dB @ 50Hz in free field and one of them is mine from circa 1980. ALL other SDC cardioids have worse LF.

eg Schoeps MK4's free field is above 100Hz.

Please do tell, give us the infos

 

[MicUlli]

Most helpful would be the following spec.
1. Free field condition (no reflections)
2. Plane wave (source is very far away) OR distance to source
3. Incident angle
With these data microphones could be compared easily...

 

[Recording Engineer]

Definitely let us know, I'd been eyeing those too, interested to hear how they are

let us know please when you receive the 92€ Ali SDC mic (Schoeps look) and how it sounds with the chineese original caps.

Well they arrived. Look and feel great! Their capsules and the Superlux S502 MKII capsules fit on each other’s respective body, but neither of them work (no sound) on each other’s body.

Just at home, I plugged them into my Big Knob and listened on my talking voice (very baritone). The CML-300 sounds pretty-damn good. Great cardioid-pattern and off-axis sounds really good! Very sensitive to plosives close-up, like the S502 MKII. If I had to guess, maybe a couple DB more noise than the S502 MKII and certainly much more proximity-effect!

 

[jp8]

Well they arrived. Look and feel great! Their capsules and the Superlux S502 MKII capsules fit on each other’s respective body, but neither of them work (no sound) on each other’s body.

Just at home, I plugged them into my Big Knob and listened on my talking voice (very baritone). The CML-300 sounds pretty-damn good. Great cardioid-pattern and off-axis sounds really good! Very sensitive to plosives close-up, like the S502 MKII. If I had to guess, maybe a couple DB more noise than the S502 MKII and certainly much more proximity-effect!

Interesting. And thanks for sharing your findings. Did you figure out why the capsules did not work on the other body? Does the CML-300 have an electret capsule with JFET maybe?

Jan

 

[Emmathom]

Well they arrived. Look and feel great! Their capsules and the Superlux S502 MKII capsules fit on each other’s respective body, but neither of them work (no sound) on each other’s body.

Just at home, I plugged them into my Big Knob and listened on my talking voice (very baritone). The CML-300 sounds pretty-damn good. Great cardioid-pattern and off-axis sounds really good! Very sensitive to plosives close-up, like the S502 MKII. If I had to guess, maybe a couple DB more noise than the S502 MKII and certainly much more proximity-effect!

Hum, they (Superlux & CML-300) seem to have exactly the same capsule's connexion... and I don't think the CML is an electret...
Can you provide please a pict of the PCBA ? and another one of "under" the interface connector ? (the white ring inserted in the mic body)
You could also measure if a voltage is present on this ring, capsule appart, when the mic is fed with 48v...
Regards

 

[ricardo]

Please do tell, give us the infos

15.0 of https://groups.io/g/MicBuilders/files/Ricardo/README.doc
You have to join.

The Calrec cardioid capsule was my baby. My plane wave tube wasn't quite as long as Jo Wuttke's.

 

[ricardo]

Maybe, “free field” means “plane wave field”, so, for example, very large distance in free field conditions. With an established manufacturer, I would hope for a standard measurement distance of 1 m of published graphs if nothing is explicitly stated (I think the Line Audio graphs are exemplary in this regard). Here is a quick simulation for a 22 mm cardioid at different distances (based on the formulas given in the Shure paper).

I make a perfect cardioid to have -27dB 1m 180 response at 1kHz. Otherwise, your shape is sorta correct.

 

[ricardo]

"Diffuse Field" and "Free Field" are entirely about distance.

Not quite.

"Free field" is at a loo.oong distance such that the sound wave is planar. So "Free field" == "Plane Wave field".

"Loo.oong" is frequency dependent.

"Diffuse field" is about picking up the reverb field which (by definition) is independent of distance.

 

[ubxf]

15.0 of https://groups.io/g/MicBuilders/files/Ricardo/README.doc
You have to join.

The Calrec cardioid capsule was my baby. My plane wave tube wasn't quite as long as Jo Wuttke's.

Thank you

 

[k brown]

https://schoeps.de/en/knowledge/knowledge-base/technical-basics/diffuse-field-1.html

 

[molke]

"Free field" is at a loo.oong distance such that the sound wave is planar. So "Free field" == "Plane Wave field".

Isn’t that what is usually called “far field” (which should be distinguished from “free field”, as pointed out above by @k brown)? No reflections (free field) are still required for the measurement though.

I make a perfect cardioid to have -27dB 1m 180 response at 1kHz. Otherwise, your shape is sorta correct.

My point was not to show a perfect cardioid simulation, but rather that a directional microphone’s low-frequency response depends on distance. In particular, an ORTF system positioned at, say, 2 or 3 m might have a higher -3 dB corner frequency than that shown in the published (on axis) frequency response (measured at 1 m).