4 Inch "Great" Speaker for Vintage Radio

javy

Member
2014-09-12 11:03 pm
Hello there guys. I'm hoping one of you guys can help since this is your expertise. I'm looking for a really great speaker for a little vintage radio I have. I'm going to gift it to my barber but I want to replace the broken speaker with a really good all around speaker. Currently he owns a Bose radio and I sort of want him to really use the vintage radio when he gets it so I kind of want a great speaker to put in this guy that kind of makes him think twice before turning on the Bose over this guy. Right now I have a FatalPro that I have left from a previous project but it's just too big. I don't want to do any surgery at all to the chasis of the radio and therefore I'm looking for a all-around speaker just as good or better than the FatalPro that I have but that the back end of the speaker is not as big as the picture attached / below. I'm hoping you guys can give some insight. Thanks a bunch in advance.
 

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javy

Member
2014-09-12 11:03 pm
Thanks Fenalaar. It's slightly open in the rear around the edges. It's an old radio that has a thin MDF board as a closure. This closure also holds the antenna. Your recommendation is great. I'll research it's specs to make sure it works out. Thanks again
 
The 927 should do nicely; it's got a moderate Q so should match reasonably to a semi-open-backed cabinet. The rising on-axis response is also worth having, as it will make the speaker useable over a reasonably wide listening axis. Flat 1m on-axis response generally translates to poor off-axis HF performance due to the rapidly increasing directionality of most cone drivers at high frequencies (there can be exceptions, but not often). If you like the 4in TB units, of the poly coned drivers, the W4-1052SDS is also pretty good -it doesn't get up quite as high as the 927, especially off-axis, so will have a slightly 'warmer' sound. Either should make quite a nice sonic match to a vintage looking box.
 

javy

Member
2014-09-12 11:03 pm
After reviewing all of your suggestions and researching each speakers specs/dimensions. I have concluded that a 4 inch replacement will not be possible. I'm thinking of getting a steel plate and using that as a bracket to use a 3.5 inch speaker. That allows me to not do surgery on the current chasis and still mimic the footprint by using a steel plate as a bracket. On paper it seems like its going to work. Back to the drawing board, need to find a really good 3.5 inch full range speaker. Thanks everyone.
 
Tang Band's W3-881SJ (neo motor type, the ferrite has a significantly lower Q) should do the job. Tang Band W3-881SJ 3" Cast Frame Neodymium Driver It's a pleasant sounding unit, poly cone, rising response up to about 11KHz with a drop-off above, which should give a suitably 'vintage' type presentation to go with the appearance. Not too expensive either. You could try something like a Fostex FE83En, but in that box you'd have little LF extension (at least, based on your description). The Vifa TC9 models may do OK, but may have a bit less output on the bottom end (these things are relative of course).
 

Fenalaar

Member
2011-04-25 10:49 pm
45 ohms is probably meant to be used in multiples, with transformer coupling or parallel connections for ceiling use. Music and announcements in supermarkets, voice in churches, music in cafeterias, radio and voice in buses are typical uses for these. You can get away with quite a number of speakers on only one amp, and stereo is not necessary in these avenues. An even sound pressure over the entire venue is the goal, not fidelity. The speakers are used with special amplifiers and transformer coupling for each.

I'd stay away from the Quams, first of all since they do not list their T/S parameters, and secondly beacuse they're not really intended for this use, so I seriously doubt they'll work well.

Johan-Kr
 
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45 ohm speakers were typically used in intercoms, where same small speaker is used as a reproducer and a microphone.
Higher than normal impedance both makes the "microphone" put out a higher voltage and the "speaker" easier to drive and pulling less current from the supply (which sometimes was a 9V battery or a few AAs).
No need for Musical fidelity nor high power, and narrow "telephonic" frequency range was more than adequate for voice-only communication.

[IMGHTTPDEAD]http://www.sentex.ca/~mec1995/circ/intercom1.gif[/IMGHTTPDEAD]

two-wire-intercom.jpg


Notice using 45 ohm speakers saves 2 transformers, it's also easier to drive at the other end of a *long* cable (typically cheap zipcord).

The circuit is very clever: is powered just by 9V batteries, you can connect a few intercoms in parallel using just a single pair wire all over the place (typically home or office) , speakers are always on "listen" and unless somebody talks they are silent and most important, power is connected (current pulled from the 9V battery) *only* while actually talking, batteries last a lot .
Each intercom has a "push to talk" button.

That said, I bet that Quam speaker is not exactly Hi Fi, simply no need to ... of course frequency response might be fine in a small AM radio.
 
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