Celestion Sr1 Manual
Celestion 3 Until recently, there were two broad categories of Celestion speakers: the DL series and the SL series. The DL series speakers are fairly conventional, low-to-moderate-cost systems of different sizes, with prices ranging from $330 to $929 a pair. Speakers in the SL series, on the other hand, are considerably more expensive ($950 to $3,000 a pair), and all of them are housed in cabinets of similar size and shape. They have a well-deserved reputation for quality among serious audiophiles in Britain and the U.S.
Classic - Vintage 3. To meet the demands of the players and their increasingly 'hot- rodded' amplifiers, we set out to develop a modern speaker.
A bookshelf system that weighs 8-1/4 pounds and measures only 12-1/4 inches high, 7-1/4 inches wide, and 8-5/8 inches deep, the Celestion 3 has a wooden cabinet finished in black and a removable black cloth grille. When the grille is removed, the speaker resembles a half-size version of Celestion's SL-6Si, with what appears to be a 5-inch paper-cone woofer operating in a sealed enclosure and a 1-inch aluminum-dome tweeter. The binding posts recessed into the rear of the cabinet accept banana plugs, stripped wire ends, or open lugs. Although no specifications or technical details on the Celestion 3 were furnished with the speakers, we were able to derive most of the relevant information by direct measurement. Price: $250 a pair. Lab Tests We placed the Celestion 3 speakers on 26-inch stands for testing. Like most small speakers, they are designed to give their best performance in a free-standing installation, not too close to a room-boundary surface.
The averaged room response was smooth and uniform over most of the audio range, varying less than ±2 dB from 500 to 20.000 Hz. The close-miked woofer response reached a maximum in the 100- to 300-hz range, falling at 12 dB per octave below 100 Hz. There was also a slight rolloff above 300 Hz, although the close-miked measurements are not valid above a few hundred hertz. Splicing the room and woofer response curves resulted in a curve showing a ±4-dB variation from 57 to 20,000 Hz. Our quasi-anechoic FFT response measurements showed that the crossover between the drivers occurred at about 2,000 Hz. The frequency response on-axis at a 1-meter distance showed a distinct output increase of about 5 or 6 dB in the range from 5,000 to 9,000 Hz that was not present in the room response or in a 45-degree-off-axis measurement.
The off-axis measurement showed that, excluding the raised portion of the axial response, the horizontal dispersion of the speaker was excellent up to 10,000 Hz. The difference between the on-axis and off-axis curves did not exceed 6 dB up to 20,000 Hz. The phase linearity of the speaker was outstanding, resulting in a group-delay variation of less than ±0.2 millisecond from 500 to 30.000 Hz. The system's sensitivity was relatively high, a 91-dB sound-pressure level (SPL) at 1 meter with an input of 2.83 volts. The impedance dipped to 7 ohms at 20 Hz and between 200 and 250 Hz, and it reached its minimum of 6.5 ohms at 10.000 Hz. Its maximum was 55 ohms at the bass resonance frequency of 82 Hz, and it measured 30 ohms at 2,000 Hz, another indication that this was the approximate crossover frequency between the woofer and tweeter. The woofer's distortion with a 2.52-volt drive level (corresponding to a 90-dB SPL in our sensitivity measurement) was about 1 percent at 200 Hz, 2 percent at 100 Hz, and 5 percent at 60 Hz, the approximate lower limit of the speaker's useful response.
Despite the small size of the Celestion 3, it was able to handle a considerable pulse power input (a single-cycle tone burst). At 100 Hz, the 5-inch woofer rattled at an input of 168 watts into its 19-ohm impedance.
At 1,000 Hz, where the impedance was 18 ohms, our amplifier clipped at 400 watts before the speaker emitted sounds of distress, and at 10,000 Hz the tweeter absorbed 745 watts into its 8.5-ohm impedance at the clipping point. Comments Good as they were, the measurement results from the Celestion 3 do not begin to describe its performance. It had a clarity and spectral balance that seemed entirely inconsistent with its size and price. There was none of the usual 'small speaker' sound character, such as thin bass or overly bright treble. It sounded the way we would expect a Celestion speaker to sound. Luckily, we were able to put that judgment to a real test, as we had a pair of Celestion SL-12Si speakers on hand. This speaker has almost three times the cabinet volume of the Celestion 3 and sells for about six times its price.
We consider it to be Celestion's finest, and one of the best speakers we have had the pleasure of using. We placed the Celestion 3's on top of the SL-12Si's, to minimize position shifts when switching, and proceeded to compare the two. The similarities between them were much greater than the differences. In fact, often the most obvious difference when we switched from one speaker pair to the other was a change in the spatial quality of the sound.
The SL-12Si is capable of creating a seamless sound stage across the whole width and height of our listening room. The Celestion 3 did no better, or worse, than hundreds of other speakers we have tested in matching this aspect of the SL-12Si's performance.
We also heard (in some program material) a slight brightness in the sound of the Celestion 3 compared with the SL-12SL This brightness appeared to come from the Celestion 3's increased treble response in the 5,000- to 9,000-hz range, an effect that is concentrated along the forward axis of the speaker. There was a substantial difference in the bass performance of the two speakers as well, even though the SL-12Si is not designed to generate large amounts of low bass. The difference appeared to be mostly in the upper bass and lower midrange, where the SL-12Si has two 6-inch drivers in operation. In their basic character, however, the two speakers were so similar that from a normal position many people would not be able to detect which one was playing. This is not a review of the SL-12Si, but being able to make these comparisons with it gives me a solid basis for saying that the Celestion 3 is one of the most outstanding small speakers I have heard, and an absolute 'best buy' at its price.
Amidst great excitement, French and Mackintosh finally perfected the loudspeaker design and, now joined by Cyril's other brother Ralph French, began manufacturing upstairs while Leonard & Edgar French continued below with the plating business. The original Mackintosh design employed a free-vibrating edge and was filed for patent on December 15th 1923 and issued as British Patent No. 230,552 on March 16th 1925. The modified French/Mackintosh design used a clamped edge and was filed October 24th 1925 and issued on January 14th 1926 as British Patent No. These numbers can be found on all early Celestion loud speakers. 1925 - The Celestion loud speaker was launched early in 1925 by The Electrical Manufacturing and Plating Co at a retail price of 6 pounds, ten shillings, with a choice of oak, walnut or mahogany cabinet.
It was sold as ‘The Loud Speaker of Distinction’ and was favourably reviewed by 'Popular Wireless' as 'a high-class instrument capable of high-class perfomances'. 1927 - The Celestion Radio Co and Celestion Ltdwere formed; it made Celestion loudspeakers and Celestion Woodroffe gramophone pickups. Loudspeaker models included the C10, C12, C14, and C24. All very favourably reviewed by Popular Wireless. The company's motto, and for many years to follow, was 'The Very Soul of Music'. 1935 - the worldwide recession hit Celestion badly, and the first ‘boom’ era came to an abrupt end.
An advertisement in The Broadcaster and Wireless Retailer of April 20th 1935 announced that Cyril French had resigned from the board of Celestion Ltd., leaving Billy Page as Managing Director. French returned to the old site at Hampton Wick to operate as sole wholesale and retail distributor of Celestion products in Great Britain At the same time, the British Rola Company, an offshoot of the Rola Company of Cleveland, Ohio, USA, had been making very similar products at Minerva Road, Park Royal, London NW10 since 1934. As well as producing speakers, they also supplied instruments to the aircraft industry. World War 2 - (Sept 1939 to Sept 1945), both Celestion and British Rola were restricted to the manufacture of one type of loudspeaker, the utility 'W' type. British Rola made theirs at Ferry Works, Summer Road, Thames Ditton, while Celestion made theirs at the Kingston factory.
The British Rola factory at Thames Ditton was virtually self-sufficient, producing cones, suspensions, voice coils and transformers ‘in-house’. The Ferry Works site had previously been occupied by Astor Engines, a manufacturer of steam engines who had used their own generators to power the plant.
It is believed that this site was the first in the country to be illuminated entirely by electricity! 1947 - After the war, the hard winter and fuel crisis of 1947 caused havoc and production was incredibly slow at both companies. British Rola acquired Celestion Ltd in April 1947, and together they covered practically the entire export loudspeaker business. 1948 - During July 1948, Celestion ceased production at Kingston-upon-Thames, and production machinery and personnel moved to Thames Ditton as a consolidation of the two companies. The company title became Rola Celestion Ltd, and 'Celestion' was adopted and registered as the trade mark for the company’s product. 1949 - Another change in fortune came about in 1949 when Rola Celestion was acquired by Truvox, a company based in Wembley and well known for its Public Address loudspeakers and systems. These covered the whole spectrum of this market and included such units as horns and loudspeakers for cinemas and many acoustic devices for the Forces which Truvox had developed and produced during World War Two.
The new Company was now owned and chaired by Mr.D.D.Prenn and the Head Office situated at Mount Street, London, with the joint Managing Directors, Billy Page and Jimmy Tyrrell, and Technical Director Arthur Young resident at Thames Ditton. This brought the Public Address loudspeaker systems into the Celestion range, where they were further developed by demands from the new petrochemical and allied industries. 1962 - New approaches were also made by the Rola Celestion laboratory staff to perfect the performance of the larger hifi speaker models, and two new types, the 15-watt CX1512 and the 20-watt CX2012 were introduced in 1962. Alongside production of the domestic and power speakers were the units of the Public Address range, many of which were designed to meet Government specifications for use by the Armed Forces, Local Authorities, Police and Fire Brigade. Built to stringent specifications these speakers often performed in extremely difficult and arduous conditions such as coal mines, chemical works, aircraft and lifeboats.
1964 - With their ears continually to the ground and their eyes on the market, the Thames Ditton design and engineering staff produced in 1964 what was to be the first of many notable Celestion hi-fi loudspeaker designs. Utilising the name of its birthplace, the Ditton 10 was launched at a critical time when it satisfied overnight a demand that hitherto had been frustrated. Offering the best possible audio quality from its bookshelf size, it was highly commended for its bass response, a quality that the pundits had always maintained could only be achieved with a large and heavy enclosure. This system remained in production for over a decade, during which period about 250,000 were made, and continued in production in modified form as the Ditton 15XR with a slightly extended response range. Around this time Neil McKinlay was appointed Managing Director. Staffing levels at Thames Ditton are estimated at 400.
Celestion's design team, fired with the success of the Ditton 10, continued the endless pursuit of ultimate sound quality. Their plans were to incorporate an Auxiliary Bass Radiator (ABR) into the system, this passive unit working in conjunction with the bass speaker to extend and reinforce the lower end of the register. Resultant of their research and engineering, the Ditton 15 made its appearance during 1966, and confounded the experts with such a low response from a small enclosure. The price was also reasonable. The Ditton 15 was eagerly sought after by the now stereo conscious public, and became the biggest selling bookshelf loudspeaker of its time. 1968 - As the demand for Ditton loudspeakers mounted, production became a problem at the Thames Ditton factory and it was decided that, as expansion at the present site was restricted by the river and road perimeters, a new location was the only obvious solution. Bearing in mind the considerable business that the company enjoyed, and problems which had been encountered with various docks in the London area, the East Anglian area was surveyed and eventually, after an initial plan to settle in Bury St.
Edmunds, a site was acquired on Foxhall Road, Ipswich. New buildings were constructed, existing ones modified and the nucleus of a work force recruited using ex-Thames Ditton supervisory staff to train the new employees. Production began in Ipswich in late December 1968. First into manufacture at the new Ditton Works, Ipswich, so named to perpetuate the original site, were the 12' Power loudspeakers of the G12 type. In the early days supply and distribution raised many problems as a vehicle was despatched early each morning from Ipswich to make the 90 mile run through London to Thames Ditton, carrying the previous day's production.
Celestion Sr1 Spec
It then loaded and returned by the same route, carrying back essential components for the next day's production, enabling the supervisor, charge hand and twelve ladies to meet their schedule. As the weeks passed the interior of the Ipswich works began to house more and more sophisticated production machinery and more staff were engaged to operate the lines, which were now able to relieve the problems at Thames Ditton in the supply of domestic speakers to the manufacturers.
The 1970's - In 1970 Rola Celestion was brought together with a publicly-quoted clothing company and the holding company created was named Celestion Industries plc The production of domestic speakers reached a peak after about three years at Ipswich, and then a shift in the market evidenced itself and a noticeable decline in this product became apparent in the factory. Its place, however, was taken by units for the ever increasing demand for high fidelity stereo cabinet systems, and at this time further expansion took place with the acquisition of a modern assembly plant on the Hadleigh Road Trading Estate on the other side of Ipswich. Ditton Works now concentrated on the manufacture in all aspects of hi-fi component units, Power Range loudspeakers and units in the Public Address sector. 1974 - With the surge of interest in hi-fi from the general public, staffing levels reached a peak in January 1974 with a total of 907 employees at the two sites in Ipswich and at Thames Ditton, some of these working night shifts.
Distribution was now wholly carried out from Ipswich by a new fleet of company vehicles, this being necessary for two reasons. The Thames Ditton factory was gradually run down, eventually closing altogether in 1975, and a new marketing policy by Celestion opened up a great many more smaller distribution points instead of the previous few selected wholesalers. 1977 - On 20th January 1977 Chairman Mr.D.D.Prenn announced the creation of overseas subsidiaries in France (September 1976), West Germany (October 1976) and U.S.A. (February 1977).
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1979 - The increasingly international nature of the company's business led in 1979 to the adoption of the name Celestion International as a corporate identity for the parent company and all major overseas subsidiaries. The 1980's- In 1980, Celestion's continued investment in technology bore fruit behind the scenes of loudspeaker design.
An instrument was developed which uses laser light to scan a diaphragm and produce moving 'microscope' pictures on a computer screen. This system taught Celestion's designers hitherto unknown subtleties of loudspeaker design, many of which remain trade secrets to this day. One of the first loudspeakers designed with the aid of the laser was the SL6, a compact two-way loudspeaker launched at the 1981 Harrogate Audio Fair.
This system contained revolutionary designs for both drive units - the bass unit was a PVC cone with an integral moulded dustcap and the tweeter was a one piece copper dome. The Hadleigh Road site had been closed down in the early 1980s and resources concentrated at Foxhall Road, which remains the international headquarters of the Celestion operation.