Category Archives: 1960’s Microphone

Shure 430 ‘Commando’ Controlled Magnetic / Controlled Reluctance Microphone (Circa 1957)

Shure Model 430 CommandoShure 430 Commando grill

The Controlled Reluctance microphone (aka Controlled Magnetic) was developed by Shure during World War 2 to fulfil the need for a battle announce microphone that could operate reliably at extremes of temperature and humidity. (Subsequently also perfect for Korea and Vietnam!)

Although the Controlled Reluctance design was in some respects similar to a conventional dynamic in other ways it was significantly different.

The 2 diagrams below illustrate the differences.

  • DYNAMIC MICROPHONEDynamic-moving-coil-diagram
  • CONTROLLED RELUCTANCE/MAGNETIC MICROPHONE (2 slightly different versions)Controlled Reluctance Microphone Sectional Diagram

Here, in response to an email enquiry, is an explanation from Shure of the working of this microphone

On 3 May 2017 15:06, “Shure Europe” <> wrote:

Response By Email (Michael P) (05/03/2017 09:06 AM)

Controlled reluctance is a variation of a dynamic mic.  The controlled reluctance mic diaphragm connects to a small lever made from ferrous material.  The other end of this lever is positioned inside of a stationary coil of wire.  Surrounding the coil of wire is a stationary magnet.  As the ferrous lever is moved by the mic diaphragm, the lever disturbs the magnet field.  This induces an AC signal (the audio signal) in the coil of wire.

Answer Link: Difference between controlled reluctance and controlled magnetic

This type of mic was originally designed for military applications.

Michael Pettersen

Shure Historian


2 pin Ampenol Connector

If you buy a 430 make sure it comes with one of these as 2 pin Amphenol connectors are hard to find.

The CR/CM elements have a high output (making them suitable for transmission over large distances) and require no additional transformer. They are therefore cheaper to manufacture than a conventional dynamic.

After WW2 Shure introduced several models for the civilian market, including the famous Green Bullet (still popular with harmonica players to this day). These were mostly budget PA mics intended for speech applications such as paging and announcements. Whilst not being particularly noted for high quality audio, their main selling points were cheapness and reliability. It is therefore not hard to see why these sturdy, affordable mics soon found favour with musicians and singers.

Apart from being highly profitable, Shure’s military communications contracts had the additional spin-off of enhancing a lasting reputation for reliability. Indeed, the company have often boasted that all of their products are tested to military standards (MILSPEC).  Even though the Model 430 was made for the civilian, domestic market it nevertheless trades on its military heritage with the name ‘Commando’ and it’s distinctive, camouflage green head!

Shure 430 Commando head

Data Sheet for the Shure Commando series.:-     us_pro_415_ug

Shure Microphones  :-  1957 Catalogue

 430 Commando Original Box

So what does it sound like?  CLICK HERE for a short clip of spoken word and Blues Harmonica.


Grampian DP4 (circa 1963) A trip down memory lane!

It was the mid 1960’s and I was a teenager at school in Manchester. Only 30 miles from Liverpool. Before the age of discos. It was a fantastic time for live music. The Mersey boom was at its height and the pubs and clubs were rocking to the latest beat groups. (It is worth noting that none of the music clubs such as The Cavern in Liverpool, or The Twisted Wheel in Manchester, were licensed to sell alcohol. Nevertheless on a Saturday night their subterranean vaults were crammed with teenagers who had often queued for hours to see their favourite bands!)

In the 5th form some of my school mates formed a group. I used to lig along to their rehearsals in the school music room. They had a couple of Vox AC30 guitar amps and an old Selmer which was used for PA. I can remember the singer turning up one day with a very shiny new microphone. All black enamel and chrome, like the headlamp on a classic British motorcycle.Grampian DP4  Removed from it’s bright blue box the mic was duly plugged into the Selmer amp. The lads then launched into their version of Buddy Holly’s ‘Peggy Sue’. The assembled hangers-on (including myself) thought it sounded amazing!

I was therefore overjoyed a few weeks ago when a friend kindly gave me this bright blue box. I recognised it straight away!Grampian DP4 Box

Grampian DP4 with clip

Just below the chrome bezel there is a ribbed rubber ring designed to prevent the mic rolling off flat surfaces. Brilliant feature!

If you buy a DP4 make sure it comes with the 2 pin mic connector as these are as rare as hen's teeth!

If you buy a DP4 make sure it comes with the 2 pin mic connector as these are as rare as hen’s teeth!

Grampian DP4 Label

Here in the UK although the Grampian DP4 enjoyed a good deal of popularity as a PA microphone, and also with amateur tape recording enthusiasts, it was never really thought of as a top quality professional instrument. Sennheiser had launched it’s superb MD21 in 1953 and followed it in 1960 with the MD421.  Around the same time AKG gave us the D19 and the D24. The poor old Grampian was not quite in the same league. However, for a while the DP4 was used by the BBC for outside broadcasts and by their Wildlife Department in conjunction with the Grampian Parabolic Reflector. (As seen on the front cover of this issue of Tape Recording Magazine from 1969 )


A few weeks ago on TV I saw an old film clip featuring an impossibly young David Attenborough in the middle of the jungle somewhere clutching a Grampian Parabolic reflector with a DP4 mounted on it.

In the end Grampian Microphones were no match for the German. Austrian and American competition. As the 1960’s rolled on bands got louder, PAs got bigger, stage monitors were introduced and the omni-directional dynamic microphone fell out of use. Cardioids simply had more gain before feed back! By the mid-1970s the Grampian DP4 had disappeared from the stage and eventually the company went out of business.

So what does it sound like? 

 CLICK HERE for a short vocal trip down memory lane!


Grampian Brochures and Technical Information (These came in the box with my DP4.)



The Shure SM58 (1966-2016). 50 Years at the top!

The Shure SM58 is a microphone I have never owned, and it is not a model that I would particularly recommend. I can always think of a better alternative. Nevertheless, if I arrive to engineer a show and find that the theatre or the PA company have supplied SM58s for all the vocals I am not unhappy with the choice! It is unlikely that any of the vocals are going to sound amazing. At best they will probably sound good and at worst they will be ok. Part of the ‘magic’ of the Shure SM58 is that whilst accuracy is not one of it’s hallmarks, it does a reasonably good job of flattering most singers. The SM58 is like Dave the rhythm guitarist in your band………… He is never going to be an inspired soloist but he turns up at all the rehearsals and can be relied upon at the gigs to play the right chords. Not fantastic but utterly dependable. A safe pair of hands!

With the 58 it is not just vocals. If you run out of quality mics at a gig and a stray conga player turns up who is not listed on the technical rider you will inevitably stick a couple of 58s on them. [NB. It is a matter of scientific observation that no matter how many microphones are used at a concert there will always be 2 x SM58s left in the case!??]  Not the best choice but they will do the trick! I once had a ‘guest’ fiddle player suddenly appear on stage during a live recording. He grabbed the nearest 58 on a stand and pointed it at his instrument. I hastily adjusted the gain and the impromptu fiddle track ended up on the album. (In fact quite a few people commented afterwards on how good it sounded!)

Shure SM58Another clue to the enduring popularity of the Shure SM58 lies in this photograph. They will put up with almost any amount of abuse!! On tour it is very hard to find one without a dented grill. In fact there is a brisk trade on eBay for replacement grills. (see pic above) You can drop a 58 regularly for 30 years and it will probably still be working  (that may not quite be true but I have certainly seen examples that look like that is what has happened!) and after the gig you can store them in a damp, unventilated van. Don’t worry; just chuck them loose in the glove compartment or in an old cardboard box under the front seat. (These appear to be popular storage solutions preferred by SM58 owners!)  Even when the paint is all corroded and chipped they will still be working just fine! A friend of mine was engineering at a festival a few years ago when an ‘overexcited’ singer vomited all over his 58. After a bit of a wipe and a rinse, unlike the singer, it was back in action! No problem!

The legendary rock’n’roll credentials of the SM58, I think, can be traced all the way back to the film of the Woodstock pop festival in 1969. The only mics used at Woodstock were in fact modified Shure 565s which are very similar to the 58 (just more shiny?!) They were used on everything from bass drum to vocals. Martin Scorsese’s film was seen by millions worldwide and in every camera close-up of the stars on stage there appeared the same Shure microphone! Woodstock was the first big festival PA system, setting a benchmark for years to come and cementing the place of the Shure SM58 in the forefront of popular music.

So Happy 50th Birthday SM58!

P.S.       If you want to listen to sound clips of this mic there are several million on the internet!


A Classic Dynamic Microphone. Sennheiser MD421 (Circa 1960)

Sennheiser MD421-2

Introduced in 1960, the Sennheiser MD421 is a robust, large diaphragm, cardioid, dynamic microphone originally designed as a general purpose tool for the German broadcasting industry. It has an excellent frequency response from 30 Hz to 17 kHz with a brightness boost at around 4-5 kHz making it perfect for speech and vocals. 55 years later the 421 is still in the Sennheiser catalogue and continues to be one of the best-selling microphones ever made!

  • Great for speech and vocals both in the studio and on stage.
  • Excellent for brass, delivering smooth full tone, and rich timbre.
  • Effortlessly handles even the loudest electric guitar.
  • Especially good on drums and percussion, producing both punch and fine detail!
  • For many engineers the 421 is the bass drum mic of choice with its ability to accurately reproduce low bass and cope with high SPLs.

Throughout the 1960’s the MD421 was adopted by recording studios and performers all over the world. Here is a review from Hi-Fi Sound (Dec 1967)

Sennheiser MD421 Review from Hi-Fi Sound Dec 1967

Sennheiser MD421-2 Side view.

The 1960’s was of course  a time of experimentation and innovation, and one unusual feature of the MD421 is that the body is made of plastic which is rare for a high quality professional microphone. Other examples I can think of (also from the 1960’s) are the AKG D202 and the D222.

In 1971 George Harrison and Ravi Shankar held their famous Concert for Bangladesh at New York’s Madison Square Garden. The stage was positively bristling with MD421s, including all of the stars’ lead vocal mics  (Eric Clapton, Ringo Star, George Harrison, Bob Dylan, Leon Russell and Billy Preston)  Check out the video: –

Sennheiser MD421 Script Logo

My Sennheiser MD421-2 pictured above with its rare script logo is a fine example from the early 1960’s. It still sounds as good as it ever did. In fact some say that the early models (which have no bass roll-off switches) sound better than the new ones!                                                                                                                       (N.B. This might just be a myth spread about by owners of old mics!)

Tech Spec for the current MD_421_II_GB

Here are some sound clips of my MD421-2 in action.

CLICK HERE for Tenor Sax

CLICK HERE for Drum Kit Overhead

CLICK HERE for Bird Song.

STC4113 Cardioid Ribbon Microphone (c.1967) Restoration

STC4113 Before Restoration

I have recently been generously given this STC4113 cardioid ribbon mic which is rather in need of some TLC. The socket on the bottom is badly damaged and I don’t even know if it works. I think that it will make a nice little restoration project. However, as yet, I haven’t fathomed out how to take it apart!

The 4113 was designed by Michael Gayford (STCs chief designer) who was also responsible for the 4104 noise-cancelling lip mic, and played a key role in designing the famous BBC / STC4038 which is still made by Coles

In today’s money 11gns (ie £11.11s) is worth about the price of a Shure SM58

Although it was the cheapest of STCs microphones the 4113 features an unusual and innovative design and Gayford’s  patent (filed in 1963) makes interesting reading.

Michael Gayford’s Patent for the STC4113

The plastic horn arrangement used in this mic to create a cardioid polar pattern appears to be somewhat similar to the one that is to be found in the Beyer M260.  In both mics the plastic horn causes a shift in the phase relationship between the front and rear of the ribbon thereby modifying the polar pattern from the usual figure of eight to hypercardioid in the case of the Beyer, and cardioid in the STC.

So on with the restoration. My first job is to sort out that connector…….. I will report back.

SOME WHILE LATER……………………………………………………………………………..

The connector problem has been solved. Preh, the company who made the original connector still make exactly the same connector. So I have bought a brand new replacement!

Having prised off the grill it was immediately obvious that the ribbon was in need of replacement.  So I decided to take the whole thing to pieces and re-build it! As you can see in the pictures below the plastic horn is glued to the circuit board, which makes it a bit of a pig to get apart! After prising it all all round with the blade of a knife the glue eventually gave way without breaking the board. Phew!!

STC4113 Dismantled Pic 1STC4113 Dismantled Pic 2And now all I need to do is to make an new ribbon, line it up in that gap, get it nicely tensioned and do up the clamps without breaking it!!!!!

This may take some time …………………………………………..

Re-ribboning and rebuilding.

Da Dah!

STC4113 Fully RestoredFully restored and repainted !!                                                                                      OK now to find out what it sounds like……………….

CLICK HERE for  my first recording which is a simple voice test.

And now for something completely different………

 CLICK here for Ukulele and Flugelbone!