Category Archives: Omni directional PA Microphone

LABOR W MD7 Omnidirectional Dynamic Microphone Circa 1950.

A Short History Lesson.

In 1945, just a few weeks after the end of World War 2 Fritz Sennheiser and 7 fellow engineers from the University of Hanover set up a business designing and producing a range of electrical equipment in a laboratory called Laboratorium Wennebostel (“LABOR W” for short). The laboratory was named after the village of Wennebostel in the municipality of Wedemark, where it had been relocated during the war. LABOR W began building microphones in 1946 and by 1953 (see catalogue below) they had developed a whole range of microphones, including the legendary MD 21 which is still in production today. By 1955 the company had expanded to 250 employees and in 1958 changed its name to Sennheiser.  

These days microphones from the early LABOR W period are becoming increasingly rare, so when this unusual looking MD7H turned up on eBay, ‘untested’ but very cheap, I immediately clicked ‘Buy Now’.

LABOR W MD7H   front view
LABOR W MD7H  front view 2
LABOR W MD7H rear view
The ‘H’ indicates that this is the High impedance version.

The photograph on eBay however, gave no sense of scale and it wasn’t until the microphone arrived that I realised just how small it is! I was reminded of the anecdote of the person who buys a gorgeous sofa online at a bargain price and when it arrives it turns out to be for a dolls house! Had I seen the LABOR W advert below that might have given me a clue.

LABOR W MD7 Advert early 1950's
‘Our most powerful moving coil microphone
MD7 for speech’

Below are the microphones featured in the 1953 LABOR W Catalogue.

Microphones featured in the 1953 LABOR W Catalogue. Page 1
Microphones featured in the 1953 LABOR W Catalogue. Page 2

(Translation of catalogue description above)

‘MD7 Speech microphone

Particularly good speech intelligibility due to emphasis on high frequencies. Therefore recommended for announcement and dictation systems. The soft rubber housing makes the MD7 insensitive to rough handling. Available in low and high impedance versions.

Dimensions: 76 x 48 x 48mm.’

For a sense of scale here below is the baby MD7 along with its Senneiser cousins the MD21 , MD421 and the mighty MD441.

LABOR W MD7 along with its Senneiser cousins the MD21 , MD421 and the mighty MD441.

Innovative design

In the early 50’s the soft rubber housing of the MD7 was an innovative design feature, and indeed made it very robust and resistant to rough handling. I haven’t tried it, but I think it would probably bounce if dropped from a height! It therefore came as no surprise once I had soldered a jack plug on to the cable it burst into life working perfectly.

So what does it sound like? CLICK HERE

LABOR W production came to an end in 1958 and the name changed to SENNHEISER. The rest is history!

Omnidirectional Dynamic Vocal Microphones

Up until the late 1960’s, cardioid, omnidirectional and figure of eight dynamic microphones were all commonly found in use on public address systems. Singers were able to choose whichever pattern suited their particular style of delivery. Figure of eight ribbon mics, for instance, were enormously popular with the jazz singers and ‘crooners’ of the 40’s and 50’s because of their smooth response and rich proximity effect which enhanced the low end of the voice. Omni was preferred by singers who required a more ‘open’ sound and the ability to move around without altering tone. Unfortunately, with the development of high power PA systems and the introduction of wedge monitoring in the late 60’s, only cardioid microphones had the required rejection characteristics to deliver a suitable amount of gain before feedback. Consequently, within a few years figure of eight and omni all but vanished from the stage and were pretty much banished to the studio!

I recently acquired a number of vintage omnidirectional dynamic mics from the tail end of the last century. Although the primary purpose of these mics was originally news gathering, my attention was drawn to the following excerpt from the AKG Engineering Data sheet for the D130. It perfectly describes the numerous benefits that an omnidirectional microphone offers the vocal performer.

AKG D130 Data Sheet.

A wide-range instrument, the D-130E offers “open”, natural reproduction of speech and music -without harshness, popping or bass emphasis. Moreover, the D-130E ‘s omnidirectional pattern and consequent absence of proximity effect enable the microphone to retain this natural quality -regardless of the relative position or distance of performers working into it. Together with its handling comfort and attractive styling, these same characteristics also lend the D-130E to a variety of hand-held on-camera applications in the studio -especially to pop-free coverage of vocalists who do not desire proximity effect.

Many singers (especially male vocalists) have an uncomfortable relationship with cardioid microphones because of their inclination towards ‘boomy’ bass and unpleasant popping plosives. I have also worked with performers who are in the habit of pulling away from the mic when delivering the loud bits leaving their voices sounding suddenly thin and weedy (N.B. Proximity effect works in both directions i.e. moving away reduces bass). With omni the bass remains constant with the desired reduction in volume.

And another thing………

For performers whose vocal style involves ‘cupping’ the back of a cardioid dynamic, maybe an omni would be a better choice? It comes ready ‘cupped’!

SM58 cuppingBeyer M58 2 N (C)

 

 

 

 

 

 

 

So…….. Here’s a thought…….

With the rise of in-ear monitoring many performers and bands are dispensing with their cumbersome (and feedback prone) on-stage wedges. So it would seem to me that for cardioid averse vocalists, perhaps now would be a good time to consider bringing back the considerable benefits of the

Omnidirectional Dynamic Vocal Microphone.

AKG D130