Understanding Vintage speakers for Early Valve Models,,, Alnico etc etc


I have been reading up on the Internet to try and get a better understanding of Vintage Speakers that suit Only Valve models Radiograms from say 1958 through to 1963.

From my understanding & I'm only going off what I have read and that said,,

Alnico are the original type of magnet for speakers. from 1940 to 1962. Very Efficient. Don't require a lot of wattage to drive them. 1-5 watts can be loud with these.

Alnico speakers tend to be pretty bright. the smaller the magnet the less power they can take without getting blown.

Ceramic speakers can handle more power, but are less efficient. They are a little darker and more midrange in sound.

1 would you guys agree with that??

2 So if you were Restoring say a 1961 Radiogram and you needed to Replace them which were the best vintage ones to get.? and what brands?

3 The other question I have is how do you know if the speakers were designed for a Stereo and not an Organ etc.etc .?



Can someone please enlighten me & give me a bit of an Education and a better understanding of this and vintage Brands , Please
ONLY Valve models...I have no interest in Radios with no valves

>>>>>>>>>>>>>>>>>pete

The type of magnet in itself is not significant, just the associated design.

The main determinant is the cone resonance. That will determine how the speaker reproduces bass and lower mid-range frequencies.

A speaker with a cone resonance of 100Hz will exhibit a peak at that frequency. Negative feedback in the amplifier will work to counteract that peak - this is where transistors are better at damping resonance in the speaker. It's one of the reasons why valves are known for introducing "colour" (read even harmonic "musical" distortion).

The larger the magnet (this generally means more Gauss), the more efficient the speaker. You can get stronger magnetic fields from ceramic magnets.

In replacing (if you can get one to fit physically) old speakers of the forties era types with ceramic does result in a small efficiency increase in sound reproduction (volume).

What you have to be careful of is "proximity". That more powerful magnet can result in an undesirable argument between speaker & power transformer and you may need to add flux shielding to stop it.

Jaycar AS 3010 used to be a good one, but I think they no longer list them?

I serviced a 1929 Lyric radio (TRF) with its original "Rice-Kellogg (RCA)" Speaker, that had been re-coned with a foam mount cone .... What a beautiful noise.

Marc