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Studio SOS: Radio Caroline

Your Studio Problems Solved
By Hugh Robjohns & Paul White

Reflections of the presenter's voice from the rear and side walls back into the Neumann mic were giving a 'lively' sound.Reflections of the presenter's voice from the rear and side walls back into the Neumann mic were giving a 'lively' sound.

In a departure from the usual home-studio make-overs, this month we answer an SOS call from the historic Radio Caroline!

Hugh was approached last year by Rob Ashard, who has been involved with Radio Caroline as an occasional presenter and studio engineer for about 12 years. UK readers of 'a certain age' will know all about Radio Caroline, which was the brainchild of Ronan O'Rahilly, the tearaway son of a wealthy Irish family. O'Rahilly established a rhythm & blues club in London's Soho area in the 1960s, and then set up a record label to promote the artists that performed there. He managed the Rolling Stones for a brief time (and bought their first set of stage equipment). The likes of Georgie Fame, the Animals and Alexis Korner were also listed amongst his acts.

However, he quickly discovered that the two music radio stations heard across the UK at that time that played 'pop music' (Radio Luxembourg and, to a more limited extent, the BBC) were only interested in playing established artists from the major labels. Frustrated with their intransigence, O'Rahilly decided to beat them at their own game and build his own independent radio station. Unfortunately, the law prohibited unlicensed broadcasting within the UK, so his only option was to broadcast from a ship anchored in international waters three miles off the coast! You can read all about the history of Radio Caroline in the side box and on their web site, www.radiocaroline.co.uk. The 2009 film The Boat That RockedPirate Radio is loosely based on the history of Radio Caroline.

Anchors Away!

Today, Radio Caroline is a non-profit organisation where everyone is involved for the love rather than money. The station plays quality music (as opposed to disposable, highly rotated pop), almost exclusively from albums. It does not major on any particular genre or era, but picks tracks from albums released over the station's near 50-year history, along with the cream of current album releases. Radio Caroline doesn't play singles as such, although album tracks released as singles do get played every now and again. The station broadcasts primarily over the Internet, 24/7, from a studio in a secret location above shops in a small Kent town. They also broadcast the Ross Revenge show on most Bank Holidays, live from the ship of the same name, which is currently being restored at Tilbury Docks.

Many of those associated with Radio Caroline back in the '70s and '80s are still involved today, with some presenters pre-recording their shows at home, and some even streaming them live from their home studios — but most use the Radio Caroline studio, and that's why Rob approached us.

The Challenge

With some Auralex and Universal Acoustics foam in place, Rob Ashard recorded some hand-claps to see what effect the treatment had had on the sound of the room.With some Auralex and Universal Acoustics foam in place, Rob Ashard recorded some hand-claps to see what effect the treatment had had on the sound of the room.

The studio is actually a large office space on the second floor of an old building in the middle of the town, with two brick outer walls and two drywall partitions, and a partial room-dividing wall across the middle. When we arrived, the studio desk and associated equipment was placed in one corner of the rear half of the room, with administrative and maintenance areas (plus an area filled with surplus gear and spare parts) in the other half.

The problem that Rob and his colleague, Cliff Osbourne, had identified was that the room's lively acoustics were very obvious whenever the presenters faded up the studio mics. This was very noticeable in the presenter headphones, and the problem was made worse by the (very modest) broadcast dynamic processing applied to the transmission stream. Clearly, some acoustic treatment was required, but what and how?

The Radio Caroline studio was upgraded last year (see 'Technical Details' box) and represents a fairly typical old-school analogue radio station. The console is a refurbished Alice Air 2000, with replay sources including Denon CD and Minidisc players, and a PC-based radio playout system. Transmission processing is carried out by an Optimod TV 8282, configured to provide some automatic gain control and very gentle multi-band compression, but no hard limiting. The main presenter is heard through a Neumann U87 microphone suspended from a very tired shockmount (held together with string and post-office elastic bands), while an AKG D202 microphone, suspended from an equally sad-looking shockmount, is available for studio guests. The studio's monitors are a pair of Wharfedale Diamond II speakers.

Happy Clappy

These two waveforms show the sound of handclaps recorded both before the acoustic treatment was in place (left), and after (right). As you can see, the contribution of early reflections to the sound was significantly reduced after the room was treated.These two waveforms show the sound of handclaps recorded both before the acoustic treatment was in place (left), and after (right). As you can see, the contribution of early reflections to the sound was significantly reduced after the room was treated.

The studio is usually occupied with live broadcasting, of course, but to facilitate our visit, both the morning and afternoon shows had been pre-recorded, so we had unrestricted access to the studio. It was immediately obvious how live-sounding it was as we walked in, and the angled wall behind and to the side of the console tended to focus reflected sounds straight back towards the main mic. The obvious solution was to treat the back and side wall with as much absorption as we could muster, working on the same principle as the classic 'SOS duvet technique'. We didn't need to worry about the low end too much as the only 'live' sound in the studio would be speech.

Cardioid microphones are very sensitive to sounds in front of them, and only slightly less sensitive to sounds from the sides. This means that not only do they 'hear' the sound source directly in front (the radio presenter, in this case), but also any sound bouncing off the rear wall and reaching the mic over the presenter's shoulders. Placing good sound absorbers behind the presenter would significantly reduce any sound rattling around the room that might otherwise bounce off the rear wall and reach the mic.

A thick double duvet hung immediately behind the singer works amazingly well, but on this occasion we decided to use something a little more glamorous.

Having examined the room and drunk some very welcome coffee with a selection of milk and dark chocolate Hob Nobs, and after Paul had finished posing at the console, we retrieved all the foam panels that I was able to squeeze into the car, and set about planning how to install them. Before we started, Rob suggested placing his Macbook Air on the console, and recording a few simple handclaps into it so that we could compare the before and after acoustics in a crude but nevertheless revealing way.

The Wall

Finally, the old elastic-band shockmounts that were used to suspend the Neumann U87 and AKG D202 were replaced with these two Rycote USM models.Finally, the old elastic-band shockmounts that were used to suspend the Neumann U87 and AKG D202 were replaced with these two Rycote USM models.

We had a mixture of Jupiter Fluted Wedge absorption tiles from Universal Acoustics, and Auralex Sonoflat panels, which were both in a burgundy colour. Unfortunately, although they were nearly the same size, the differences between metric and imperial measurements soon became apparent... The Auralex panels measured two feet square and two inches deep, while the Universal Acoustics tiles were 600x600mm and 50mm deep. We thought about alternating the tiles to average out the size discrepancy, but in the end we all agreed that the best aesthetic effect was achieved with the Universal Acoustics fluted tiles as the first row, mounted immediately above a dado rail and with the flutes vertical so as not to trap dust. The plain Auralex tiles were placed above the Universal Acoustics ones, to maximise the absorptive area. The latter inevitably extended slightly beyond the bottom row because of the size variance, but no one seemed to mind!

In all, we had two rows of six tiles, which, since the console was set up close to a wall on the left, extended around the corner. An additional tile was glued to the loft access hatch directly above the console, and another propped between the computer display monitors, to act a little bit like a Reflexion-style filter. The idea was to add further screening to the rear of the mic, while also minimising the sound of the presenter's voice getting out into the room, thus reducing the strength of reflections coming back. This could be removed very easily in an interview situation, to maintain eye contact with the guest.

Foam Calls

Rob Ashard (top) and Cliff Osbourne (bottom) in the newly revamped Radio Caroline studio.Rob Ashard (top) and Cliff Osbourne (bottom) in the newly revamped Radio Caroline studio.

Fitting the tiles was very straightforward, after we had removed the large number of classic band-related posters adorning the studio walls! Relatively small amounts of spray adhesive in the corners of the tiles, with an emphasis on the upper edge, was sufficient to fix the tiles firmly to the wall, aided considerably by the technical dado rail that supported much of the tiles' weight. We didn't want to apply more glue than necessary, as the tiles may have to come down again some day! We had to cut one of them to fit around the door entry phone and door release switch, which we did with a sharp Stanley knife. A serrated bread knife actually works fairly well for this too, and an electric carving knife is even better. Band saws give the neatest finish but, sadly, Paul had left his at home, and although he seemed quite keen to explore the nearby B&Q superstore to see what was on special offer, we decided to make do with the simple knife.

The Wharfedale Diamond II monitor speakers were located directly on symmetrical rack cabinets either side of the console, so to minimise any vibrations that might cause the cabinets to rattle, we used a couple of small grey Universal Acoustics wedge tiles to provide some isolation.

With the acoustic tiles in place, we could already hear a massive difference in the room's acoustics, and it was even more dramatic when auditioned over the microphone and headphones — the room was substantially more controlled and dead-sounding than before, but without being unnatural or oppressive. Rob set up his Macbook Air again to repeat the clap test and, after normalising the before and after audio files and listening to them, the reduction in the amplitude and duration of the room's reverberation was quite dramatic and pleasingly effective. The laptop screen picture you can find elsewhere in this article shows the untreated room's reverberation on the left and the post-treatment reverb on the right. The two audio clips are available to download online at /sos/sep12/articles/studiosos-media.htm if you want to audition or examine them yourself.

Rob and Cliff professed themselves very pleasantly surprised and pleased with the improvement, both in terms of acoustics and visual aesthetics — as well as the speed with which we had been able to transform the room. That left them only to find new homes for the vintage posters we'd had to remove to make space for the acoustic panels!

After our visit, we were able to persuade our generous friends at Rycote to donate a pair of USM Studio shockmounts and a clip-on pop-shield to replace the very tired Neumann U87 and AKG D202 mounts. The axis of maximum isolation isn't strictly in the correct plane for the D202 (it being an end-fire mic), but Rycote don't currently make an InVision mount of sufficient size, and the USM is still better than the previous mount.

In the following days, other presenters apparently confirmed the success of the Studio SOS makeover too, and hopefully Radio Caroline's band of loyal listeners — which now includes ourselves! — appreciated the difference.  

Reader Reaction

Cliff Osbourne broadcasting from Radio Caroline's former headquarters, the Mi Amigo ship, in the '70s.Cliff Osbourne broadcasting from Radio Caroline's former headquarters, the Mi Amigo ship, in the '70s.

Rob Ashard: "I think that the most surprising element of Hugh and Paul's visit was the ease and speed with which a significant change was made to the room's lively acoustics. Just walking behind the mixing desk before we'd even sat down at it, Cliff Osbourne and I immediately noticed the difference.

"The following evening, Cliff did his usual Friday evening 6pm-to-midnight programme (quick plug!) and noticed that he didn't have to 'work the mic' anywhere near as much as he'd had to previously. I've also noticed when listening at home that the mic sounds crisper too, as a result of this work. Another aspect of the treatment is that I think the studio looks much better for it. I quite like the colour of the tiles, and they somehow impart a cosier feel. Vibe is quite important in a radio studio, and anything that helps that is a good thing!

"Both our mics had extremely tired suspension mountings, and Hugh arranged for new ones to be sent to us from Rycote. Two different models arrived, as the main mic, our Neumann U87, is much larger than the guest mic, which is an AKG D202. Installation took just minutes. These are great bits of kit. After some experimentation with the pop shield, which proved extremely effective, we opted to stick with our old foam wind-gag on the U87, as we felt the pop-shield pushed us a little too far away from the mic, undoing some of the good work done by the foam panels.

"All of us at Radio Caroline are very pleased and grateful to the SOS team for the improvements they have made, which we feel have a positive effect on-air, as well as making the studio a nicer place to be for our presenters.”

The History Of Radio Caroline

Today, Radio Caroline's studio is based around an Alice Air 2000 console and a PC running BCX broadcast software.Today, Radio Caroline's studio is based around an Alice Air 2000 console and a PC running BCX broadcast software.

This isn't the first SOS call that Radio Caroline have made: one night in March 1980, the Mi Amigo ship that the station used to broadcast from lost its anchor in heavy seas and ran aground on a sandbank. The ship didn't survive, but the crew did, thanks to the Royal National Lifeboat Institution. Radio Caroline relaunched in August 1983 from a former Icelandic trawler called the Ross Revenge, fitted with the tallest ever ship-borne structure: a 300ft radio mast fed from an equally impressive 50kW AM transmitter.

Sadly, history was repeated in 1991 when this ship ended up on the Goodwin Sands. Thankfully, it got off intact and is now in Tilbury docks being restored. Its studios are fully functional and broadcast live from the ship on some Bank Holiday weekends.

Radio Caroline's fame was at its peak back in the swinging '60s. It was the first of many offshore pirate radio stations dotted around the UK coastline, coming on the air over Easter in 1964, and really taking the country by storm. Until then, pop music was severely rationed by the BBC, with many programmes actually playing BBC Radio Orchestra copies of popular songs, rather than the real thing! The pop pirates broadcast using studios and transmitters on ships and maritime sea-forts that were outside British territorial waters. When all-day pop-music radio arrived, "the kids went wild,” as they said at the time! This is portrayed in the 2009 film, The Boat That RockedPirate Radio, which is based on the Radio Caroline story.

While Caroline's '60s era was all about pop music, it became an album-format station in the 1970s, staying away from the more disposable pop-music singles. Instead, it played mostly album tracks from artists with generally higher production values, so that as well as the obvious tracks from the Beatles and the Rolling Stones, listeners heard Supertramp, Yes, Pink Floyd, Stevie Wonder, The Eagles, Steve Miller, Fairport Convention, Deep Purple, Bad Company and Steely Dan.

Radio Caroline exists today as an extension of this period, with the involvements of many of the DJs who served time aboard the Ross Revenge in the '80s, along with many of the '70s crew too. No-one gets paid, and the money comes from some advertising and contributions from its many dedicated supporters. However, Radio Caroline isn't locked in the past — its album-format approach pulls tracks from today's quality artists too. Expect to hear the Foo Fighters following the Stones! Internet radio is growing at an amazing rate and Caroline has been there for many years now.

Technical Details

The equipment rack at Radio Caroline, which houses meters, network routers and, in the middle, an Orban Optimod 8282 automatic leveller and multi-band compressor.The equipment rack at Radio Caroline, which houses meters, network routers and, in the middle, an Orban Optimod 8282 automatic leveller and multi-band compressor.

The Radio Caroline studio was given a make-over in the summer of 2011, when an Alice Air 2000 mixing desk was acquired second-hand. This was a very popular desk in UK radio and is a true workhorse. Despite a previous hard life, it had no scratchy pots or bad switches — partly because many of the physical knobs and faders control VCAs (voltage-controlled amplifiers) rather than acting upon the audio signal directly.

The studio's main microphone is a Neumann U87 (there isn't much better for spoken word), and the guest microphone is an AKG D202. This features two separate capsules for the high and low frequencies, and a passive crossover to connect them, in much the same way as you have a woofer and tweeter in a two-way loudspeaker.

Music replay sources include two seldom-used Minidisc players and a dual CD player, with most of the music (along with some pre-recorded shows) coming off a PC running an excellent British radio-automation software system called BCX. This has four independent 'players' arranged across the top of the screen, which feed into four stereo channels with yellow faders on the desk, via an M-Audio Delta 1010LT interface connected to the computer. The players can be started remotely from the console's big red buttons, thanks to some Heath Robinson engineering involving a cheap USB keyboard and some major surgery to fool the keyboard's USB driver into thinking the F5-F8 buttons are being pressed!

The Alice mixer output is fed into the transmission audio processor, an Orban Optimod 8282, which processes the audio in the digital domain, despite its analogue I/O. While many FM radio stations set their processors to achieve the loudest (most compressed) sound on the dial, this can lead to listener fatigue. Research has shown that many of Radio Caroline's listeners tune in for many hours at a time, so the Optimod is set much less aggressively than it is on other stations. The audio is first evened out with an AGC (Automatic Gain Control), so that the five-band compressor that follows it has a consistent level to deal with. A protective output limiter guarantees the maximum output level but is rarely triggered, and the signal then goes into the streaming computer, via an Emu soundcard, to head off into the big World Wide Web!

Published September 2012