of how the concert of May 9th, 1959 compared with our three previous demonstrations in the Festival Hall. I do so with pleasure. because there are many differences-some plus and some minus-
some expected and some unexpected-which may be of interest to readers in general as distinct from those who patiently sat through the event.
As we were playing stereo from disc (six items) for the first time in a concert hall, this article might well have been headed " Fourth Dimension ", the extra dimension referring to the unknown prob-lems of using two channel discs in such a large hall, as well as to
the sound reproduced. Although we ran into serious hum and rumble trouble with this disc stereo, 1 do not think we ought to be blamed on this account (We deserve a medal.)
Musical AspectMusically, I should say that this was easily the best concert we tave given, The programme was well balanced, and the changes from recorded to live and vice versa were perfectly timed by Peter Walker and John Collinson, with well chosen volume levels. The result was that the time passed quickly. We also played every item as per programme and ended within three minutes of the specified time. With only half a day for a final rehearsal, this was not so easy as it sounds. (Another medal?)
Here we came a bit unstuck on two items and I should like to explain why, so that too much blame is not placed at the door of recording engineers. Fortunately for professional musicians, there is always a subtle difference between a live and recorded perfor-mance. On this occasion, we came reasonably near with the organ and oboe, but the piano and bass solos were tonally off the mark. (One medal returned.)
Live vs Recorded
The piano item sounded much better at rehearsal than at the concert, and I can only assume that the acoustical effect of the audience suited the R.F.H. piano better than our recording, which already had a warmer tone. This often happens; but with the organ Mr. Walker considered the results to be better during the concert than at the final rehearsal, contrary to expectations.
As regards the fine bass voice, a combination of conditions produced an unsatisfactory tone. These were: (1) Studio coloration in recording; (2) Platform resonance: (3) Cabinet resonance. In a more resonant hall we could have got away with some of these effects, but in the R.F.H. any one of them is enough to spoil the comparison. Given more time, we could have dealt with faults 2 and 3.
Our four main speakers are always placed on a concreted section of the platform at the back, and the cabinets are lined with tiles and asbestos sheet to avoid resonance which tends to develop when they are raised on castors. The cabinet used for the solo had not been so treated, and was not the one used at the first rehearsal in February-hence the trouble, and no time available to cope with this on May 8th along with hum and rumble which also cropped up unexpectedly.
When flying by jet, the main problem is space: all you get for an extra Ј25 on a Comet flight to New York is another few inches of .leg room. In the R.F.H. the problem is time-there is plenty of space! Although we booked the hall in January, the morning and evening periods of May 8th and 9th were already allocated for rehearsals and concerts. Still, it is always a good idea to try to learn from mistakes; and we have booked the Colston Hall, Bristol for a demonstration on October 9th along the lines of the R F.H
Bristol Demonstration on October 9th
Photograph taken during the Concert on May 9th, showing Denis Mathews receiving a great ovation for his piano solos in which he alternated in perfect timing with recordings of him-self. Mr. Briggs is seated on the left of the platform with Raymond E. Cooke at the controls.
event, when we hope to prove that Harold Blackburn's fine voice can be well reproduced in a modern, non-resonant concert hall.
Hum and RumbleFor the first time in 14 concert hall demonstrations we ran into this sort of trouble, due entirely to disc stereo. The main problem was 100 cycle hum because it was almost inaudible in some parts of the hall, but built up to a peak in other places, due to phase effects. The propensity for hum and rumble displayed by a good magnetic stereo pickup means that, for concert hall working, the standards hitherto acceptable in motors, turntables and general layout will no longer suffice. Furthermore, the equipment should be placed on a slab of concrete, because panel resonance is even worse for the pickup than it is for a loudspeaker.
Several correspondents have referred to the hum and rumble heard an three or four items, but they all-with one exception- seem to be prepared to make due allowance for the difficulties. The exception was a Mr. B. who says he can do better at home. So can I.
Might I suggest that here is a question for Ralph West and Stanley Kelly to get their teeth into? I can't do it myself as 1 have none of my own teeth left, but a few tests made by Raymond Cooke indicate rumble and hum levels 10-15 dB higher with stereo heads than with mono types-excluding, of course, crystals.
Mono RecordsFor convenience, we played these with the stereo pickup, and 1 think they suffered slightly on this account. I prefer a moving coil mono pickup and I am pleased to say that my technician Raymond Cooke agrees with me, and so do Stanley Kelly and George Wise, who have had considerable experience in the design and testing of pickups of many varieties. The difference is only slight, say ship's tea compared with fresh water tea; but in the R.F.H. the minutest difference shows up. A sprat becomes a mackerel, if not a whale. Wild horses will not separate me from my best mono pickups.
StereoHere the Decca pickup came into its own, and I must say I liked the sort of sound it produced. There was a trace of bass resonance and woolliness on some loud passages, but I put this down to the rumble and hum to which 1 have already referred. It would be unfair to blame the pickup, the records, the amplifiers or the loud-speakers tor these effects, although it is conceivable that a certain loud passage of music in a groove could excite the vertical resonance of a stereo pickup and arm assembly.
Audience reactions to stereo were many and varied, and did not depend entirely on listening position. In fact, a friend of mine who sat in a box at the side during the first half of the concert, and in the centre stalls during the second half, actually preferred the stereo as heard in the box.
I thought the demonstration proved that stereo has a quality of depth and colour which is lacking in mono, and that omni-directional speakers provide a wide, acceptable listening area, But the adoption at stereo at home remains a purely personal question.
RepeatMany letters have been received expressing regret that this looks like being our last R.F.H flutter; but there are powerful arguments against a further effort.
Expense is quite an item. The hall costs Ј350, artists nearly Ј200, special recordings Ј100, publicity Ј200, plus say Ј100 incidentals. Total near enough to Ј1,000 to make no difference. Sale of tickets produced Ј400 with a full house. The nett cost is not unreasonable if things go well, but where should we be in the event of a major breakdown during the demonstration?
Stereo Needs Longer RehearsalProbably the strongest argument against a repeat is this difficulty of obtaining reasonable rehearsal time in the R.F.H., and the necessity for much longer rehearsals due to stereo. A full half day could easily be taken up by listening to various records with the loudspeakers in different positions on the platform, although you always end up with a choice between a position which suits the music and one which suits the hall, and often the twain do not meet. To mask room or hall resonance, two speakers must be spaced well apart, and we do not like to disturb cables by moving heavy speakers during a concert.
Finally. I suspect that we are all more difficult to please than we used to be, but we still have one medal left-for hum?
We can, as usual with these large-scale efforts, appropriately end · with the abbreviation Q.E.D. in preference to Q.E.F. Once you reach the Q.E.F. stage, the game is up.
Hi-Fi News, 1959
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