I am planning on making a speaker with all 8 ohm drivers, tweeters, 5 1/2" mid, 8" woofer. I'm thinking of just wiring them all in parallel and using a high pass capacitor to step the signal from low to high. Will this work? Is there something I need to consider when doing this kind of design? I absolutely don't want to get into modelling x-overs or building a fancy 3 way x-over, I realllly want to keep it stupidly simple and just tweak the roll off points and be done.
Hi and welcome to the forum!
The minimum requirement is to make sure that both the midrange and tweeter are protected from the bass frequencies present in the music.
The simplest way of doing this is to wire a bipolar (non-polar) capacitor in series with the midrange driver and a smaller value one in series with the tweeter (see attachment). You may need to include an attenuating resistor for the tweeter.
This arrangement will work, but of course will be far from optimum!
The capacitor values will depend on the required crossover points of the midrange and tweeter drivers.
Now let the fireworks begin! 🙂
Attachments
@Galu I took apart a pair of Advents once and this is exactly how they were wired up on the inside. Perhaps the drivers were engineered to work that way.
The issue I have with actual x-overs is being locked into specific values for parts due to the fact that the theoretical never align with the real world.
The issue I have with actual x-overs is being locked into specific values for parts due to the fact that the theoretical never align with the real world.
Have either of you ever seen a speaker where it was possible to attach a woofer and the x-over will engage for the woofer section? Then, if the woofer is removed the circuit turns off and the main speaker handles the lows.
This to me is just like: ‘I want a car and I want it to have two wheels and no engine, because otherwise it gets way too complicated…’
If you are contemplating the uncomplicated arrangement that I attached, then the two crossover points should be at least 2 octaves above the resonant frequencies of the midrange and tweeter drivers respectively.
The resonant frequency (Fres in Hz) of each driver should be stated in the driver specifications, so look them up in order that nominal capacitor values can be suggested.
P.S. I will stress again - the results will not be optimum.
That is the case with some expensive loudspeakers, but mass market loudspeakers of the past often relied only on capacitors for filter duties.
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What are your drivers, please? There may be other, built projects which might give you some clues about the crossover and cabinet.
8 ohm tweeters are not common but there are some old 3 way designs with, for example, the Dayton DC28, DC130 (5") and DC200 (8"). You could have a look at them, check the driver specs and see how they compare with what you have. Not ideal in any way, but might be helpful.
Geoff
8 ohm tweeters are not common but there are some old 3 way designs with, for example, the Dayton DC28, DC130 (5") and DC200 (8"). You could have a look at them, check the driver specs and see how they compare with what you have. Not ideal in any way, but might be helpful.
Geoff
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This is nonsense, especially if you are designing the crossovers yourself. While the component values may be fixed at discrete values (e.g. E12 range), you can mix 'n match to your heart's content. Anyway, your proposed approach is way, way more inaccurate than your bemoaned "theoretical" approach. Simply put, the problem you describe is not a major one and is easily dealt with. Evidence for this is the multitude of successful commercial and DIY project.
It will work, why not.
But chances that it will work well are slim to zero.
You need drivers with smooth, well damped response and nice HF rolloff.
And, as already noted, high pass points must be well away from resonant frequencies of mid and tweet.
And, as already noted, high pass points must be well away from resonant frequencies of mid and tweet.
In that case guess you won’t be able to post and read forums, or use a phone, or..
Maybe a better use of that money would be building a reputable kit, like the Travelers from Meniscus, or Discovery 3WC mkII from Jantzen