Category Archives: Microphone Tech Specs

AKG C451E (Circa 1970) A Classic from The Golden Age of AKG

Today AKG is little more than a brand name owned by a multi-national corporation. Like a tired old rock star it rests on the laurels of its former glory whilst still churning out a few old favourites.

However, if we go back to the late 1960’s and into the 70’s AKG was a powerhouse of innovative design and high-tech engineering. Major achievements include the D200 series which took dynamic microphone design to a peak which even today sees few competitors. This period also saw the legendary C12 condenser evolve into the C414 which continues to be a favourite in studios across the world.

In 1969 AKG launched its newly developed Condenser Microphone System (CMS) using audio frequency circuitry with Field Effect Transistors. This was a fully modular microphone system based around the C451E, the inherent features of which were claimed to be;

  • Low noise level,
  • Extremely high reliability and
  • Life-long sta­bility.                                                                                                    

AKG C451E with old style logo

AKG C451E no serial number

A selection of interchangeable capsules and extension tubes could be purchased along with a variety of accessories covering a wide range of recording and live sound applications. The CMS proved to be enormously popular with broadcasters, TV companies and studios throughout the 1970’s and beyond, and can be seen on many BBC music programmes of the period.

These contemporary AKG brochures/guides explain the features of the CMS in detail.

AKG C451 CMS Technical Specifications

Technical Info AKG CMS microphones.

AKG CK1 CapsuleAKG C451E with capsule removed.AKG C451E body with CK1 Capsule

C451E original case interior AKG C451E Original case

My C451E

Judging from the old style of logo and the lack of an externally stamped serial number on my newly purchased C451E (see top 2 pics), I think that it must be a fairly early example. It is in perfect condition and even the case is hardly marked. As always it was a bargain!

So What Does it Sound Like?    

Sadly, like many, many other people I am stuck at home at the moment practicing social distancing, and so recording music with my beautiful new C451E will have to wait until the current COVID-19 pandemic dies down and we can all get back to work!

Meanwhile Stay safe!

P.S.   Went for a walk today and recorded this:-    https://www.youtube.com/watch?v=k5MHEL6ZPHI

 

‘The Beatles Mic’ Reslo RB/L Black Label (Circa 1961)

Reslosound Ltd were a British company based in Romford, Essex, manufacturing microphones and electrical equipment throughout the 50’s and 60’s. In recent years the Reslo RB has become known as ‘The Beatles Mic’ because of its association with The Beatles early days at The Cavern Club.

However, as I recall (‘cos I’m that old), the Reslo RB was simply a popular vocal mic with many up-and-coming young beat groups in the clubs and pubs around Liverpool and Manchester. Like the Shure SM58 today, the Reslo RB was not, perhaps, the greatest vocal mic in the world, but it wasn’t bad either, and most importantly it was pitched at a price that gigging musicians could afford! In 1962 the Reslo RB/L could be purchased for £9.12s, which was less than half the price of an AKG D19B. A Sennheiser MD21 cost £16gns, or if you couldn’t quite afford the Reslo you could always settle for a Grampian DP4 L at £8. For their first gig at The Cavern in 1961 The Beatles were paid £5.

So how on earth did a delicate ribbon microphone survive whilst an enthusiastic singer (straining to get heard through a 50watt Vox PA) screamed ‘Twist and Shout’ at a distance of half an inch? (Or in the case of my mate’s band, an old valve amp built into a re-purposed rabbit hutch!) Reslosound clearly knew their market and gave this problem some thought. To avoid instant annihilation of the ribbon, Reslo had a cunning plan! Firstly the RB was designed with the ribbon motor facing backwards i.e. with the ribbon nearest the back of the microphone and thus somewhat shielded by the magnet. Secondly the RBs were supplied with a set of fine fibreglass ‘ acoustic correction pads ‘.

Reslo Filter Pads Kit 1961

These had a range of functions, described in detail in the Reslo Instruction Manual. However, the most important purpose of the pads was to prevent the implosion of breath on the ribbon.

ResloRB_INSTRUCTIONS_TECHDATA

In the almost inevitable event of catastrophic failure Reslo also had ‘Plan B’ in the form of replacement ribbons which came mounted on a plastic frame ready to do a quick swap.  It was also not uncommon for musicians to replace a blown ribbon themselves using the thin aluminium foil that came in cigarette packets! Having heard the results this is not to be recommended……… but it worked!

Rolling Stones 1963

Another bunch of likely lads with a Reslo RB. The Rolling Stones in 1963

The BBC Connection

In 1961 the BBC were looking around for small, unobtrusive microphones to use on TV. After serious deliberation, and thorough testing of the Reslo RBM/T, the Research Department concluded that ‘The performance of the microphone fell short of broadcasting standards’ (a night out at The Cavern would have told them that!).  However, the cheapness and robust construction of the RB was also noted, and they therefore suggested implementing a number of simple changes to the design which would bring it up to broadcasting specification. The full report can be read here…….

 1961 BBC Modifications.

The modified broadcast microphone is known as the Reslo VRM/T

The VRM/T was sold to the BBC for the princely sum of £10 per microphone.BBC TV Grandstand Reslo VRM/T

Home Taping

The Reslo RB was also popular with amateur tape recording enthusiasts. Once again, it gave good results without breaking the bank. The British tape recorder manufacturer Ferrograph sold Reslos with some of their machines and made their own in-line transformers to match them to the input. Here is a review of the RB by Fred Judd, who edited Amateur Tape Recording magazine for a number of years……. ResloRB_review by F Judd

Reslos also appeared in re-badged versions for various equipment manufacturers including VOX and GEC.

Conclusion

Fronting many famous (and not-so-famous) names of the 60’s the Reslo RB has rightly earned a place in rock ’n’ roll history, and thanks to its solid design there are many examples still in circulation. With a bit of a clean and a new ribbon they will probably carry on rocking for another 60 years.

So what does the Reslo RB/L sound like?

CLICK HERE Pete Gill with Reslo RBL

P.S.    If your Reslo RB needs re-ribboning or if you fancy upgrading to BBC spec http://xaudia.com/ do a fantastic job.

 

Sennheiser ”Telemike” (Circa 1976) with ME20, ME40 & ME80 capsules.

Sennheiser ''Telemike'' Operating Instructions. 1976

Sennheiser Telemike with ME80, ME40 and ME20 Capsules

My eBay bargain with K2-U powering module and MZF 802-U 100Hz filter.

Below, page from ‘Telemike’ manual.Sennheiser Telemike Operating Instructions 1976Spezial Teleskop MZS 802

Sennheiser’s ‘Telemike’ is an extremely versatile, high quality, modular, electret microphone system originally designed for reporters and film makers. It consists of a powering module K1, K2 or K3, a metre long telescopic boom arm MZS 802, (how cool is that?) and a choice of 3 interchangeable microphone modules (ME-20 Omni, ME-40 Super-Cardioid or ME-80 Shotgun) There were  also a number of accessories such as the 100Hz filter, windscreens and various clip mounts and table stands.

Unlike all of the other Sennheiser microphones in my collection ‘Telemike’ is extremely light. Even with the ME80 attached to the telescopic boom it adds very little weight to a camera or portable tape machine, making it an attractive tool for location recording. Back in the 70’s an additional benefit of the telescopic boom was that it kept the microphone at a distance from the motor noise of the camera or tape machine.

Apart from professional users ‘Telemike’ also attracted an army of amateur video camera owners and tape recording enthusiasts. It was easy to use and came with a handy booklet of instructions on how to connect Sennheiser mics to a huge range of tape recorders from 51 different manufacturers!! (No that isn’t a typo!) My Dad was a tape enthusiast with an interest in local history, and so when I was a child we always had at least 2 tape recorders in the house! The microphones that were supplied with domestic machines were usually of poor quality. These Sennheiser mics offered the keen amateur a huge improvement in sound quality. They also produced excellent results with more professional machines such as the Revox A77 and B77 which did not provide on board phantom power.

CLICK HERE  for a short voice demo of ”Telemike” featuring all 3 capsules.

Original Users guide and Technical SpecificationsSennheiser MKE 202 User manualsennheiser mke202 manual002sennheiser mke202 manual003sennheiser mke202 manual004sennheiser mke202 manual005sennheiser mke202 manual006sennheiser mke202 manual007sennheiser mke202 manual008sennheiser mke202 manual009sennheiser mke202 manual010

Sennheiser MKE 202. (with K2pre-amp)Sennheiser MKE 202Sennheiser MKE803 (K3 pre-amp with 3 position bass roll-off)Sennheiser MKE803

These versatile modules can also be simply used either hand held or stand mounted. All in all, a very useful set of microphones!

 

 

Wind Shield 4001.A. to fit STC4032 and 4035

In the post yesterday came a small cardboard box  containing a very pleasant surprise. On reading my last post on the STC4032, one of my readers had observed, that I didn’t have the 4001.A. wind shield. These days they are extremely hard to find. He happened to have 2 and so he sent me this as a present! That is very kind and made my day. So, a big thank you to John Machling

Wind Shield 4001.A to fit STC4032 and 4035

And it is in absolutely perfect condition!

The construction of the wind shield is interesting, consisting of a cleverly designed dome of fine wire mesh packed with rubberised hair and other fibres. (Even the thickness and spacing of the wire and hair/fibre is critical! ) An airtight rubber seal easily attaches the wind shield to the mic.

Inside view of STC4001.A. Wind shield

No. It is not a nest for an extremely small bird!

Inside rim of STC4001.A. Wind shield.

To understand exactly how this slightly crazy-looking piece of vintage British technology works it is worth reading the original patent application which explains all. 

Patent Application for STC4001.A.

STC4032 with 4001.A. Wind Shield.STC4032 with 4001.A. Wind ShieldSTC4032 wit 4001.A. Wind Shield

With the wind shield in place, the level of noise caused by winds in the range of 10 – 30 mph  is reduced by up to 16 db, with surprisingly little effect on the frequency response. It also provides a valuable additional layer of waterproofing. It certainly looks like it should be very effective, and as soon as we have some really bad winter weather I will get outside and record a demonstration!

 

STC4032-D Outside Broadcast Microphone Ex BBC Circa 1955

STC4032-D

STC4032-D

STC4032C Advert

From the earliest days of outside broadcasting and recording, keeping the microphone dry has always been something of a challenge. Condenser microphones in particular don’t function well in damp conditions, and pretty much any mic can be completely ruined by a good soaking.

These days’ companies such as Rycote make windshields and water resistant protection to cover a wide range of different professional microphones. Back in 1955 STC came up with their own neat and convenient solution to the problem.

Advertised rather grandly as being ‘an all weather instrument’ with ‘full marine and tropical protection,’ the STC4032 is a robust hand-held, omnidirectional, dynamic microphone with a moisture resistant black Bakelite body. The grill is a dual layer of fine stainless steel mesh and an optional windshield (pictured above) may be added to give an additional 15db noise free performance in high winds and additional protection from the rain. The handle incorporates a switch, which can be wired to provide muting or remote start/stop function for a tape recorder (such as the E.M.I Midget).

EMI Midget Tape Recorder

This super lightweight setup was used by BBC outside broadcasters from 1955 until the mid-60’s and weighed a mere 14lbs!  You may laugh…….. But this was a vast improvement on carting round the previous equipment…….. a BBC Type C portable disc recorder weighing 44lbs!!!   (see pic below)   Perfect for recording in a gondola!                                                                                                     BBC OB Disc cutter Venice 1946Michael Reynolds reporting for the BBC in Venice 1946.

Can’t imagine the rocking of the boat helped the disc cutter very much. The mic is an STC4017c and none of this gear is waterproof (apart from Michael’s sturdy military raincoat!)

Legendary sports comentator David Coleman

Legendary sports commentator David Coleman with his trusty STC4032 in hand.

The following is a hilarious period piece, almost like something out of Monty Python:

Alan Whicker interviews Beatniks in Newquay in 1960  (STC4032 appears at 5min 50secs)

https://www.youtube.com/watch?v=W3WfXA9JL9w&t=350s

Actress and opera singer, Rosalina Neri.

This picture of actress and opera singer Rosalina Neri being interviewed for the BBC really deserves a suitable caption!                       ………………………………………………………………………………

STC4032-D

STC4032-D

Although it looks somewhat like a World War 2 battlefield telephone, in terms of technical performance the STC4032 is exactly the same as the STC4035 studio microphone, and very similar to the famous Apple & Biscuit STC4021. It has a notably smooth frequency response from 30Hz to around 10 kHz, with a presence peak of around 5db at 6.5kHz . The only difference with the 4032 is the water resistant case.

Technical Specifications.

STC4032

Here is a short demonstration of the STC4032-D

In Conclusion.

Although ostensibly designed for outside broadcasting, the STC4032 is a high quality dynamic microphone that could be used for many different tasks.

Click Here for a short except from Suite for Soprano Saxophone and Church Organ – ‘In Remembrance’ composed and performed by Patsy Gamble with Jonathan Hope on Sat 11th Aug 2018 in Gloucester Cathedral. Photograph by Duncan Laker.

Click Here for a short clip of Acoustic Guitar. Many thanks to Joe Martin for the brief impromptu solo.

P.S.

For those who are interested in the history of broadcast recording I would thoroughly recommend these 3 sites which are a rich source of fascinating information:-

http://rfwilmut.net/broadcast/recording.html

http://museumofmagneticsoundrecording.org/StoriesBBCEMI.html

http://www.orbem.co.uk/repwar/wr_recorders.htm

The Parabolic Microphone.

In the Beginning.

The notion of using a parabolic reflector to pick up sounds from afar has been around for many years.

With the advent of aerial warfare in the First World War, the British military started developing acoustical devices to provide early warning of incoming enemy aircraft. The first ‘sound mirror’ was erected in Maidstone in April 1915. During the 1930s, in the run-up to World War 2, a number of these enormous concrete parabolic reflectors appeared along the South coast of England and at other strategic locations. The largest of these structures could detect aircraft at a distance of 25 miles. However, the whole project was abruptly abandoned in 1938 with the invention of Radar!

WW1 30ft Sound Mirror

The listening ‘trumpet’ seen on this dish could be rotated to find the strongest signal. This would enable the listener in the control room beneath the dish to calculate the direction of the incoming aircraft. The information could then be relayed to anti-aircraft batteries.

Parabolic Ears

A ‘stereo’ device like this could be used to pick up activity in enemy positions and provide early warning of attack. (That is if you could hear anything above the sound of your mates laughing their heads off!)

The Parabolic Microphone

In the post war years with the rise of television and the increasing popularity natural history broadcasts on both wireless and TV, sound recordists were quick to adopt the parabolic microphone i.e. an omni or a cardioid microphone, mounted facing inwards, at the central focal point of a portable parabolic dish.


Parabolic MIcrophone

The author recording birds in the trees down at the bottom of the garden.  CLICK HERE to share in the joy!

A parabolic reflector has one significant advantage over other sound pick-up devices: it is a noiseless acoustic amplifier. The frequency response and polar pattern are a function of the size of the dish used. The enormous concrete military dishes of the 1930’s were often 30ft in diameter or more, enabling them to detect the lowest frequencies of an aircraft engine over huge distances. For the modern wildlife recordist a somewhat smaller portable dish is something of a compromise! For a narrow forward beam of 10 degrees a 60cm diameter dish gives around 14db (x5) gain to frequencies above 500Hz. A 1m dish will give 20db (x10) gain to frequencies above 300Hz. The forward gain of a reflector is defined as the difference in output level between a microphone which is reflector-mounted compared to the same microphone unmounted. Even with a modest sized reflector, the on-axis sound of the chosen subject is greatly magnified without adding any of the hiss and hum associated with electronic amplification. However, given the narrow beam characteristics of the dish, one thing that the recordist should bear in mind is that if the subject moves off axis the tonal quality of the sound will change. This can be difficult if for instance the subject is moving around in a group of birds. For that reason I would suggest that the parabolic dish is at its best when recording an isolated single subject.

Frequency/ Directional Response Plot for a typical parabolic reflector for wildlife recordingParabolic Dish Frequency plot

Using an unmounted microphone there are many wildlife recording situations in which it is simply not possible for the sound recordist to get close enough to achieve a good signal to noise ratio. As you creep up with your microphone the subject simply flies off or runs away! ……..Or in the case of dangerous wild animals it may be the sound recordist who does the running! The parabolic dish enables the sound recordist to record from a safe distance without risk of disturbing the subject or getting eaten!

One of the most common problems with wildlife recording is that quite often the perfect recording opportunity comes up without warning. Animals and birds are not predictable. Hence, my minimalist, rapid response kit, illustrated below is light, portable and very fast to set up. I can be in record in a matter of seconds!

The Parabolic Microphone. Minimalist Wildlife Sound Recording Kit

  • Extremely light weight, flexible, 50cm plastic parabolic dish available from new UK company innercore
  • Aluminium handle on the back which can also be screwed on to a tripod
  • Simple microphone mount marked at the focal point.
  • HMN Sound MicroLav. N.B. to prevent wind noise a Rycote Furry windshield is recommended. (Not pictured.)
  • M-Audio MicroTrack II set to record in mono at 96kHz 24bit.
  • M-Audio in-ear headphones with industrial ear defenders over the top for isolation.

Walking by a local lake the other day I came across a small flock of Canada geese about 40ft away quietly pottering about on the grassy bank. Suddenly one of them started squawking/honking. I started recording and within a few seconds it flew high into the air and passed straight over my head. On the recording the strange creaking sound of the bird’s wings and the movement of air can be clearly heard. It sounds close up, even though the bird is at least 30ft above me. It then flies round the lake and lands back with the others and carries on honking very loudly. Definitely not a bird you would want to get close to! Would probably make a good guard dog!                                                                           CLICK HERE to take a listen.

Other Uses for the Parabolic Microphone.

When listening to sporting coverage on radio or TV you may have enjoyed the additional excitement of hearing the ball striking the bat or the racket. You may hear the close-up thunder of the horse’s hooves in a race or the grunts and shouts of a rugby scrum and…… Not a microphone in sight!

In Conclusion.

My purpose in writing this post has not been to advertise the merits of a particular set of equipment but merely to suggest some of the possibilities and fun to be had recording sound using a parabolic dish.

P.S. (Nov 2019)  I have just come across this fascinating patent by British Acoustic Films Ltd from 1931 ( !! ) for a Parabolic Microphone for use in film production, recording and broadcasting.  Parabolic Microphone B.A.F Ltd 1931       It even includes a setup whereby sound can be recorded (and mixed) from 3 independent reflectors aimed at 3 different sound sources simultaneously using a single microphone!  Wow!

Mélodium 76A 1960’s / 70’s

Looking like a cross between a Van Gogh Sunflower and a pepper pot, the Mélodium 76a is a shining gem of chrome and aluminium. A classic of French design!

Melodium 76A Front Grill

In the 1960’s Mélodium developed a variety of modular parts and accessories to give their range of microphones greater versatility and customers more options.

The basic 76A microphone (head) came with a choice of 10 ohms or 200 ohms impedance.

Melodium 76A Head

The mic could be used plugged straight into the cable. (Great for harmonica players!)

If required this handy plug-in transformer converts the 76A from 200 ohms to Hi-Z.

Melodium 76A Transformer

There was also a choice of handles.

Melodium 76A Detachable handle

Melodium 76A with 314 Handle

In this 1970’s Mélodium Catalogue (below) the technical details of the microphones are presented along with a full range of parts and accessories, including goosenecks, tall stands, short stands, table stands and a large selection of adapters, switches and transformers. It is a very comprehensive selection, to cover every possible application.

CLICK Here for MelodiumCatalog

Sadly these days it is hard to find much information about Mélodium. Even in its heyday the company was little known outside of the French speaking world. By the end of the 1970’s Mélodium were no longer in business. Probably wiped out by the superior German and American competition.

Melodium 76A

Finally

Having finished re-soldering all of the joints in my eBay ‘bargain’, I just need to plug it in and find out what it sounds like!

CLICK HERE for Sound clip of Voice and Blackbird in the garden.