Three vs four-way speakers: a sensible question.

[stf92]

Hi: I have an old four-way speaker (=speaker system) with only the OEM woofer remaining. As I own a pair of 45mm, soft dome Yamaha tweeters comfortably going down to 2000Hz, my first thought was to make the old speaker into a three-way one. OK.

However, I also have the OEM crossover, and the crossover freqs given by the manufacturer. So, an alternative would be to simply get the drivers to fill in the three upper bands.

Knowing of this beautiful forum, I have decided to leave the decision to people who really knows. Or in other words, what do you think?

[jerome69]

Hi, can you give much more details ? Do you have a photo ?
Not so easy to tell.

[wintermute]

hi stf92 finding three drivers that will match your original crossovers well enough to work out ok is a very unlikely occurrence.

New drivers will mean new crossover whether 3 or 4 way. Most will suggest not even tackling a 3 way as a first project. So if you are going to go down the route then I'd say definitely a 3 way instead of a 4 way.

Have a read of the sticky Introduction to designing crossovers without measurement for a good grounding in crossover fundamentals.

I myself would not consider trying to design a crossover without measurements, but the above thread is an excellent introduction.

Tony.

[stf92]

Hi and thanks, wintermute. First of all, I'll have a look at your suggested reading, and try to study it at a later time.

I have a 4-way, acoustic suspension baffle, and the OEM woofer and crossover. The crossover freqs, are 500, 5000, 10000Hz, as givenby the manufacturer. Its circuit, just in case you are interested, is here
.
Following your advice, I'll redesign for a 3-way. I have a Yamaha 45mm soft dome 4-ohm tweeter which Yamaha placed inside its NS-625 two-way baffle, specifying a 2000Hz crossover freq. So I have two pieces of information: the c/o lower freq must be 500Hz, just as it is now (the filter is independent from the other ones, being in paralell with the amp output). And I must redesign for an upper c/o freq of about 3000Hz.

The woofer is 8-ohm while the tweeter is 4-ohm, but I'm looking forward to solve this little issue. Please have a look at the circuit. I'd be very much interested in your opinion. Regards.

[wintermute]

Hi stf92 the link doesn't work for me. You can re-use the part of the 4 way crossover that is currently on the OEM woofer but the rest you will need to re-do. With some luck maybe some of the components can be re-used

I'd suggest looking at 4" or 5" mid-woofers or full range drivers for the 500-3000 range. something with a smooth rollof without nasty breakup will make crossover design a lot easier.

Be aware that starting from scratch with something like this is a BIG challenge.

Tony.

[Conrad Hoffman]

IMO, 2-way has some inherent problems with driver selection and crossover because you're trying to stretch the response of the drivers over a wide range. 4-way is usually more of a marketing gimmick because to do it well gets very expensive. 3-way is optimal for me. You should be able to choose three drivers and get them installed, then look at various crossover designs and see what parts you've got that can be reused. If the frequencies are close or even halfway reasonable, using resistors to control driver levels will likely get you most of the way to good sound.

[stf92]

Thanks for your kind replies. I'll take good notice of what you say, and try not to dismay in the way.