Just how critical is the choice of drivers for a three way speaker design?

[RMutt]

I ask because, although they have not arrived yet, I am beginning to mull over the work needed on some wrecked, but only £1.23 worth, Goodmans Magisters. What surprises me is that Goodmans and other manufacturers of the time managed to use the same tweeter and midrange design in very different speakers, from small bookshelf types to the fifteen inch bass types of the Magister. I appreciate that work may ( or may not!) have been done to the crossovers, but given some peoples insistence of the critical nature of driver choice, how did they do it? P.S. Whilst googling for information, I came upon a tweet from late last year by Whispering Bob Harris thanking his Magisters for 40 odd years service, as he was finally retiring them off.

[walpurgis]

Your best bet is to stick with the correct driver line up for the Magisters. Try and find the right midrange unit to replace the odd one. eBay lists them from time to time. If you experiment with alternative drivers you'll likely run into impedance and sensitivity mismatches. You could extend the bass end by using bigger sealed cabinets, mind you there's plenty of bass from these.

[RMutt]

Thanks Geoff. I actually have a pair of midrange drivers already, plus a slightly different set of old Goodmans midranges, leftovers from my Magnum project. On the Magnums I changed the mids for Vifa domes and the tweeters also to a Vifa pair. In the end I fitted adjustable l-pads to the mids and tweeters to get the sensitivities right. I have been more than happy with the result, certainly streets ahead of the original sound. I do wonder if these older models were 'voiced' to accommodate the ancillaries of the time, in that the upper frequencies are a bit forward. I can't wait to get stuck into them. Should be here tomorrow.

[walpurgis]

I've heard Magisters a good few times and not regarded them as peaky in general and although the DT3 tweeter has a slight sting at the top, the overall balance is very good. As you suggest Andrew, the partnering equipment has an influence, although many seventies solid state amps were bright sounding rather than dull.

I quite like the Goodmans tweeter and have used it in several speaker projects and also as a super tweeter as there is output up to nearly 23kHz.

[RMutt]

Magisters came today. Wow. They're wrecked. Cosmetically they're gone, but....I think I'm going to love them. Bass drivers are working, mids are a mismatch, one is louder than the other for a start. Tweeters are both blown. But wow, how come I still like them? I don't know but there is just something about the scale of the sound, a presence . Tomorrow I'll have a look inside.

[walpurgis]

Well have fun Andrew.

They must be sortable. There's a pair of mids which I believe are the correct ones and a pair of the tweeters (in grey) on eBay at the moment.

[RMutt]

Well what a dogs dinner. Had a look inside. Neither tweeter is connected, so may work, I don't know yet. Oddly, both wires to the tweeters have been cut off and the wires from the crossover finished with a cable connector, but one of these wires appears to have been soldered at some point? One tweeter appears to have been connected red wire to red dot on tweeter the other black wire to red dot. Is the latter out of phase? Worse to come, one bass driver has had a piece of card wedged behind it in the frame, presumably to correct rubbing or something. I would not be surprised if this one vibrates when I connect them back up. They are filled with the usual settee foam and the crossover looks identical to my Magnum one, although I don't now any values yet. Plenty to do. Thanks for the heads up on the ebay stuff Geoff.

[RMutt]

Capacitor values are exactly the same as my Magnums, how does that work then? Tweeters don't work. Pulled one apart and under the dome is stuck a small piece of foam that has turned to dust so probably would not sound as it should anyway. I bet all the old Goodmans tweeters are the same. Fixed the vinyl lifting from the bass drivers. For anyone who has Goodmans drivers with the vinyl lifting, this is what I did. I warmed the dustcap edges with a hairdryer, this softens the glue and you can carefully lift off the dustcap. I then applied a thin layer of Copydex to the under side of the vinyl and the onto the cone and using the hairdryer to soften the vinyl I smoothed it down onto the cone. I then glued back the dustcap. I've replaced the binding posts modern ones to make it easier to plug and unplug the speaker cables whilst I'm messing about with the speakers.