Friday, December 14, 2018

Comparing some classic cardioid, omnidirectional moving coil microphones on vocals


The objective of this experiment was to find out how close one could get to a great bright with no bass heaviness produced quality of singing voice with a minimal signal path.


Also testing many mics with the gentle slope Pleiades (R,L) filter so that all mics can be used close thereby eliminating any room artifacts improving signal to noise ratio at the same time.


Observing if the bright MD421 would be better at more real singing with backing track conditions.
Singing this time was while a backing track was playing. Music seems to mask high frequencies so very bright mics like MD421 which were somehow dismissed in older Pleiades experiments may prove to be just right or even perfect at almost real conditions.


A 1:2 high quality (preliminary) transformer was used to step up the impedance of 200Ω to 800Ω for generously driving the mic preamp (SONY) with high S/N.


Signal path:


Is it OK if I Call you Mine (Fame Soundtrack) playing not loudly in an adjacent room from Pleiades 2N3053 and Philips full range speaker - male softly signing voice - (Pleiades 130Ω,40mH) - Western Electric D165831 1:2 transformer of 1H primary inductance - Sony TC-D5 PRO - Sennheiser HD580


Below is the list of mics tried with the objective to effortlessly approach the sound quality of voice as on Fame Soundtrack irrespective of prestige or price or angular patern:


Sennheiser MD421 HN early vintage with old style lettering Sennheiser logo
Possibly the best. Pleiades filter needed at 1-2in and no low cut from mic. If the low cut from mic is used distance can be greater, sound quality is different. No s problems.


Shure SM58 Mexico
Problems with s, (could this particular mic be a fake Chinese?, it was bought new from a shop).


Shure Unidyne III (vintage SM57) made is USA
Excellent. Needs the Pleiades filter for 1-2in very clear and bright sound. Slight s problem.


Shure Unidyne B 515SD made in USA
The best together with MD21 HN
No s problems, great sound with HF and nice midrange


Sennheiser MD21
Great but perhaps too much bass or treble
Used with Pleiades filter at 1-2in


Sennheiser MD441 U3
Great but some sense of plastic sound although very smooth
With Pleiades at 1-2in


Electro-Voice RE15
Top quality, possibly the best.
Less than MD421 but extended HF with Pleiades filter at 1-2in, no LC. Very smooth sound.


Electro-Voice 635a
Great. Pleiades filter needed too.
Omni mic. Sounded exceptionally clear like omnis. There was some kind of 4-6KHz? peak, obstacle pressure doubling effect?


AKG D130
Great.
Pleiades filter needed. Big and clear. But again some 4-6KHz? Peak?


AKG D58
Sounded like telephone. No Pleiades filter needed. S problems.
S


No name SM58 shape.
Very nice. Used with Pleiades filter. Exceptionally nice for a no name mic. No s problems.
S


Unknown EU.AM EL1600 CP-B
Very nice. No Pleides filter needed. Seems reasonance frequency is adjusted for flat response at small distance.
S


Sennheiser MD211
Impressive. Needs Pleiades filter for bass heaviness reduction.
Very extended treble. No s problems. A bit sense of plastic but smooth sound. Amazing microphone.


AKG MI 201-100
Very nice, no Pleiades filter needed.
Less HF which is nice for a Capella singing.


Paso M8
Bass heavy. Still bass heavy with Pleiades R,L. Best with just A Pleiades L. Low output.


A systematic problem of above tests is that a constant Pleiades filter of 130Ω, 40mH was used. Different R, L values may better suit different mics. Perhaps a variable Pleiades filter is needed.



Later addition:


A similar test was repeated with most of the above mic including Grampian DP4/L, DP6/6.


More natural results were with AKG D130 and even more with Grampian. Then 25Ω DP4/L black needed a Pleiades filter where as a 70Ω DP4/L gray and the DP6/L did not need. They were just connected to the Western Electric 1:2 transformer.


See also adding the Grampian ribbon to the comparison test:
https://euroelectron.blogspot.com/2018/12/adding-grampian-gr1l-ribbon-mic-to.html


Later addition:
It may be difficult to decide what would be the mic to hold if one could only take one. At the time of writing possibly the Sennheiser MD211 with a Pleiades (R,L) filter.


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