1920's Horn Speakers

[David Simpson]

Do many Forum folk use these old horn speakers these days? Are they supposed to be matched with their manufacturer's radios. I.e. Burndept to Burndept, and so on ?
I've had a shufti on the internet, but cant find any info on specific makes. I've just been given 4 of these big beasts :- A Burndept, a Browns, an Amplion, & an un-named one which might be a BTH. This is a new vintage radio experience for me, so don't want to make an a*** of repairing/restoring them
There seems to be a mercenary audiophool trend to offer them on eBay as "Bluetooth" conversions, but I reckon that's sacrilege.

Regards, David

[Cobaltblue]

I have a dozen or so they are amagingly efficient if a bit waspish
Problems you tend to find are OC windings they are typically 2000 ohms and weak magnets.
I have got a couple including a nice Amplion Standard Dragon where I have mangaed to conceal a small Neodymium magnet and its worked wonders on its performance.
Many have adjusters to set the critical distance between the pole peice and the diaghram you turn them till there is a pop as it pull off the pole piece then re-adjust for best sensitivity/sound.
I also have a Burndepy Ethovox with Mahogony Petals and cast ball and claw feet its a magnificent beast.
You can use them on anything designed for that sort of load so mostly 1920's manufactures sets and early 1930's kit sets such as the Cossor Melody Makers
Cheers
Mike T

[HamishBoxer]

I have a AJS F4 with matching AJS speaker (1924) ,though if the impedance is correct surely any make should be fine.

[Gridiron]

Its nice to match up a 20's radio with the same manufacturer's horn but horns were sold separately. Best sources of information are catalogues of the period, some of which have been reprinted, such as the BVWS reprint of the Brown Brothers one for 1925 and adverts in magazines of the period, the American Radio History website may help here. Radio Radio has a section with horn speakers in. If you post a photo of the one thought to be BTH it may be identifiable.
Mike.

[Paul_RK]

I think the mixture of companies and their products was not too dissimilar from what prevailed in the hi-fi marketplace 40 or 50 years later. There were firms producing radios but not horn 'speakers, or at least far better known for their radios than their 'speakers, and there were others (S.G. Brown, Amplion...) whose loudspeakers had a far greater market share than any ventures they may have made into radio production at the time. In between were BTH, Sterling etc. whose radios and loudspeakers were both fairly prominent. While there wasn't any real advantage in going to the same manufacturer for receiver and 'speaker, marketing would sometimes emphasize how ideally balanced a combination the purchaser wise enough to do so would obtain.

Paul

[peter_scott]

I use my BTH horn instead of headphones. Usually for use with early radios.

I also have a BTH crystal set and in the past was able to tune to a station 25 miles away and hear it on the other side of the room using the BTH horn with no amplification.

Peter

[PJL]

I have a little ericsson and a larger Spartan. The Spartan was a mess and needed a rewind and every so often I have to take it apart to trim the jammed mazak 'piston' that adjusts the distance between the coils and diaphragm. They look pretty and work OK but are just oversized headphones.

[AC/HL]

They are, and like their smaller cousins should be connected so that the DC field assists rather than depletes the permanent magnets.

[David G4EBT]

Aside from the original query about matching, the main advantage of horn loudspeakers is they are more efficient. They can typically produce approximatively 3 times (10 dB) more "sound power" than a cone speaker from a given amplifier output, which is why they came into use in the early days of wireless and gramophones. (It's often been said that the term 'put a sock in it' originated from putting a sock in the horn of a gramophone to reduce the volume).

Horn speakers (different shape of course nowadays, except for megaphones), are used extensively for public address systems, as intruder alarms & fire alarms sounders, and in cinema sound systems and some domestic audio systems. The shape of the horn wasn't just 'aesthetic' - it was (still is) determined by quite complex physics and maths.

By no means an obsolete concept:

https://en.wikipedia.org/wiki/Horn_loudspeaker

[David Simpson]

Got some pictures, Chaps.
They also came with some weird & wonderful old TRF Coils. Some are 6 pin with the base's wee sockets in a cruciform layout. The 6 pin plug-in coils are by Lewcos.

Regards, David

[David Simpson]

Well folks, research has revealed that the 4 speakers are :- Amplion "Swan Neck" AR15 1923 - - - SG Brown "Hunting Horn" 1924(similar to the Type Q) - - - Burndept "Ethovox" 1923 - - - and an Ediswan "Televox" from 1925/26.

Regards, David

[David Simpson]

All 4 h/speakers are about 95 years old. Me thinks that very few folk these days carry out in-depth repairs.
I've cleaned/repainted/varnished etc the base units of the Amplion & the Browns.
However, and here is a warning, I suspect that the original paint was lead based. A lot of Dremmel work & rubbing down with fine emery paper, plus cleansing with meths - produces a toxic mix ! Hence I've suffered an upset stomach & a bit of a headache. So have temp stopped, to give my system chance to recover.
The duff coils will need replacing or rewinding. But meantime - found two modern 3" dia, 3ohm res., 5W o/p wee speakers which amazingly temporarily fit perfectly into the base units. So the Browns is fully working & plugged into my Ferranti 145, & sounds ok.

Regards, David

[David Simpson]

Last job before Christmas - got the nasty split in the Oak horned Amplion mended, then lacquered & polished. Also have a temp 3ohm speaker in the base unit. All Tickerty Boo.
Just as a 1920's display, have put it alongside the Oak cabinetted Allscott III, & they look the bee's knees.
New Year project - get all the wee duff 2000 ohm coils rewound.

All the Best to Forum folk for Christmas, David