Expert moving coil speaker

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emgcr
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Re: Expert moving coil speaker

Post by emgcr »

This is superb Dave---thank you so much for these very rare and detailed insights. Ginn’s letter really does help to illuminate more of the man’s character. It took me quite a while to read the letter so I have printed it out, which I hope is helpful :

March 28/39

Dear Mr Simon,

I have not yet received your speaker unit and I am very sorry that you have had the expense of sending it to me. We have not made that type of speaker for over four years and there are no spare parts obtainable for it so that when it does come I am afraid that I cannot do anything at all to it.

I have just perfected my new speaker which is the most wonderful thing I have ever heard : it is much better than any horn.

I am not at liberty to give full technical details yet but I can tell you that it is 4 ft high by 2ft square and can stand in any part of the room, even in the middle of the room. It is absolutely non directional and no horn can give anywhere near the same result. We have already had a laboratory test of 15,000 cycles in the treble and 30 cycles in the bass through the speaker. It is really wonderful. It can be seen off any set (sic).

I should feel very proud to build one for you. The price is 25 Gns and it is a handsome piece of furniture, of course hand made. If you order one simply state if you want oak, mahogany or walnut, light, medium or dark and if the finish is to be full polish or matt. Let me know as soon as possible. There is sure to be a rush, when it becomes known and I want any one I build for you to be a credit to my name.

My best respects to yourself and your good wife,

Yours sincerely,

E M Ginn

I was unsure on first reading whether the date was 1931 or 1939 until I checked the address of the firm which was located at Frith Street from 1936/39. Thus the letter was written when he had been in the “Expert” business for getting on for ten years. It would also seem reasonable to conclude that Ginn made the speaker units from about 1931 to 1935. Presumably, with such a short life, audio quality could not have been the greatest and sales must have been slow. You say your example is in working order and it would be fascinating to hear a recording in action together with your considered opinion.

Am I right in assuming that your Senior horn bronze spigot would appear to sit around the outside of the male equivalent on the speaker unit ? If so, there must be an inner step which would militate against sound quality compared with the situation of a continuous smooth bore in the original all-acoustic record-playing system.

Here is an extract from The Gramophone in May 1940 showing the sort of speaker Ginn may have been referring to in his letter :
Attachments
Expert advertising 1940.
Expert advertising 1940.
Last edited by emgcr on Fri Jan 28, 2022 5:18 am, edited 1 time in total.

streetmechanic14
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Re: Expert moving coil speaker

Post by streetmechanic14 »

To answer a few questions:
fran604- I've never seen a speaker remotely resembling what's inside the case (which itself looks to me like "Expert" work) so my assumption is that it's all Ginn (or Phillips).
emgcr- You are exactly right about the joint between driver and horn; possibly economic considerations prevented giving this a genuinely smooth bore- the inside chamfer on the driver being the best that could be done.
I must confess it's been many years since I had this in operation. When I did, it was driven by a Victor RE 45 amplifier (push-pull triodes, likely the best America had to offer short of broadcast or theater equipment in 1929-30) and a Western Electric 4A pickup. I can't remember exactly what disappointed me in its performance except to say it was in direct competition with the Expert acoustic gramophone and the winner in a contest like that was a foregone conclusion! A transformer in the RE 45 amp has since quit and the whole contraption has long been silent.
Both the speaker and the Expert Senior gramophone turned up together at a rural outdoor flea market in (I think) 1989. It occurs to me now what a bizarre photo op the sight of two Expert horns towering over everything else in such an unlikely setting was, but I must have been so intent on getting money out of my pocket that the photograph was never taken.
chunny- Here it is in all its glory, maybe not graceful but in no danger of tipping over.
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IMG_9744a.jpg

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fran604g
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Re: Expert moving coil speaker

Post by fran604g »

Thank you for bringing this unique speaker to the forum. Your post will hopefully live on in perpetuity and perhaps another - or additional info - may turn up one day.
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emgcr
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Re: Expert moving coil speaker

Post by emgcr »

Very many thanks Dave for all these inputs which are hugely appreciated. May we be allowed the privilege and treat of seeing your Expert Senior please ?

I also thought you might be amused to have the link to a couple of fun experiments I carried out a few years ago using a small bluetooth speaker at the base of an EMG Xb Oversize horn and another using a concentric magnet driver on the end of an Xb EMG tonearm.

https://www.youtube.com/watch?v=DbtikGV8WHo Bluetooth speaker driver. (Seen clearly on horn at end of video).

https://www.youtube.com/watch?v=M2ZLAdn-zBE&t=0s Period concentric magnet driver. (Seen twice during video).

The sound quality of the concentric magnet driver is nothing like as good as the bluetooth but interesting nontheless. I imagine this is something similar to your experience with your two set-ups ?

streetmechanic14
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Re: Expert moving coil speaker

Post by streetmechanic14 »

Thanks for all the kind words. Am I correct in assuming the "Rathbone Place" address suggests my gramophone was made very shortly after Ginn's "departure" from EMG- 1930 or 1931?
It's a little surprising that one of the two horns has a sort of varnish over the paper while the other has no coating of any kind. The varnished horn is easy to keep clean but I've had to be satisfied with gentle dusting of the other-
so pardon its dusty appearance in the pictures. Of course in this it matches the rest of the house so I shouldn't complain.
It has the four-spring sound box and Paillard spring motor.
-Dave
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IMG_9747a.jpg
IMG_9746a.jpg
IMG_9745a.jpg

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emgcr
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Re: Expert moving coil speaker

Post by emgcr »

Very many thanks and it is wonderful to have discovered the existance and whereabouts of another magnificent instrument. Your comments about the varnish finish on one of the horns is interesting. This could have been done by initial request when new or, perhaps more likely, by a subsequent owner---we shall never know. Are we talking about just the exterior or is the interior also varnished ? In my experience it is not a good idea to have a bright surface on the inside as this tends to encourage odd reflections adversly affecting sound reproduction quality. If one is varnished internally, do you notice any difference in the comparative sound ? Presumably the horns are interchangable ? This was not always the case for some strange reason as I have come across one bronze spigot with a larger diameter than the usual size ! However, the securing threads are the same so it is possible to unscrew and swap around.

Ginn was located at 55 Rathbone Place from inception of the new business in June 1930 until 1933. He relocated to 10A Soho Square between 1933 and 1936 and then moved to 64 Frith Street from 1936 to 1939. Unlike EMG, I am afraid he did not use stamped production numbers so we cannot narrow the dating further than that. The thought is that he did not want to draw attention to just how young the firm was ! My own Senior has no badge at all and has the number 2 (probably a workshop number) stamped into the underside of the tonearm flange but maybe suggesting the possibility of being an early model---also with Paillard GGR 255 spring motor. Additionally, mine does not have a tonearm rest. I see yours is similar which might also point to early production ?

streetmechanic14
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Re: Expert moving coil speaker

Post by streetmechanic14 »

emgcr-
I have to compliment you on the sound you get from your horn drivers. As far as I can judge from my computer speakers both provide very pleasant listening. Is the concentric magnet unit an aftermarket adapter from the '20's, the sort of thing meant to be mounted on a gramophone tone arm in place of the soundbox? If so, the results are surprisingly good. Many of these things were sold in America but development here seems to have stopped about 1924 and, of course, the sound is markedly inferior to what I hear from yours.
It's impossible to say now which horn went with which device but it's just possible the varnished horn was an attempt to "brighten" the sound of the loudspeaker (at whose suggestion I wonder) and even that the request-for-repair letter to which Ginn's is the response might have concerned disappointing reproduction of high frequencies.
Ginn's handwriting is certainly not easy to decipher so it might be of interest to mention that the former owner's name was Dewar Simons, of an old New York family descended from (or anyway claiming descent from) Menno Simons, the 16th century Protestant theologian.
-Dave

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emgcr
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Re: Expert moving coil speaker

Post by emgcr »

streetmechanic14 wrote: Thu Jan 27, 2022 4:00 pm Is the concentric magnet unit an aftermarket adapter from the '20's, the sort of thing meant to be mounted on a gramophone tone arm in place of the soundbox?
No, it is the driver taken from a later aluminium "racecourse announcer" and then adapted to the EMG tonearm. The diameters were roughly the same but, in essence, everything is unmatched ! Just a bit of fun really but thank you for your compliments.

Thank you also for correcting my misreading of Mr Simon's name. The provenance you mention is most interesting.

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