Introduction to designing crossovers without measurement

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It looks like you have 1.6uF plastic film capacitors. These are generally long lived devices and may be OK. MKT indicates polyethylene, and when faced with the choice many would prefer polypropylene (MKP, FKP). The difference, if any, will be small.
 
It looks like you have 1.6uF plastic film capacitors. These are generally long lived devices and may be OK. MKT indicates polyethylene, and when faced with the choice many would prefer polypropylene (MKP, FKP). The difference, if any, will be small.

I'm pretty sure MKT is polyester.
Am I wrong?
Wolf
 
Thank you, guys. Actually, in the meantime, I have found out what it really is. MKT 1.60 is an old marking for today's MKT 100 line of polyester capacitors produced by Sharma. The capacitance is 10 uF, 10%. I finally got hold of a LRC tester. It seems to work fine, but I'll still replace it by a ClarityCap polypropylene.
 
Thanks for all the info. I have been doing a ton of reading and this is by far the best, clearest and easiest to understand for a new comer to the crossover world. However I still would like some guidance on how this is all finally hooked up together after calculations. Is there somewhere I should look? Something about the basics getting this all working correctly together? Any help would be appreciated.
 
Hello, I've finalized my crossover components.
These are for a 7 watt set feeding highish (@100 db/watt home made 3 way Onken style speakers.

I was given some fancy ohno 20 gauge solid wire; is this thick enough, to wire the parts together, for the small amount of power the crossover will be passing?
 
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Yes, it should survive the heat. On the other hand solid wire isn't very resilient to vibration so if you decide use it, fasten it to take the weight off the speaker connector and leave a little looseness there, using gentle bends to face the connector.
 
Yes, it should survive the heat. On the other hand solid wire isn't very resilient to vibration so if you decide use it, fasten it to take the weight off the speaker connector and leave a little looseness there, using gentle bends to face the connector.

Thanks. These will be outboard crossovers, terminated at input and output with binding posts. You make an interesting point about vibration I have never considered.

I have some ancient isobearings, made of sorbothane. Now I plan to pass each solid core wire through a chunk of these. Don't know how much, if any, vibration makes it to the crossover components, or amplifier, from the speaker drivers along the wire, but it must be harmless to damp it, more than not at all.
 
Help!

I have a pair of Minimus 7 die cast aluminum speakers and i salvaged coils and capacitors from a pair of M7W. They are similar in measurements; C1=C2= 4.7 uF and L1=L2= 0.4mH.
The original crossover was filtering low frequencies to 1 inch dome tweeter (8 ohm) but the 4 inch woofer had no filter. Am i correct to assume that the woofer is actually duplicating some of the frequencies of the tweeter then.
I plan to take the salvaged parts to make a 2-way crossover putting the cap in parallel and the coil in series. Will this make a noticeable difference?
 

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Am i correct to assume that the woofer is actually duplicating some of the frequencies of the tweeter then.
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will this make a noticeable difference?
On the surface, the less duplication there is suggests the less difference it will make.. and there obviously isn't too much or they might(?) not have been made that way.. but when you listen to a woofer on its own without a filter they typically have an edge to the sound, gaps and peaks at the top end where the cone isn't operating as satisfactorily as it should, before dropping off.

Adding a filter can trim this, adding a controlled rolloff while limiting the bandwidth. Using the same coil/capacitor combination for both woofer and tweeter is a reasonable choice for a random assignment (without measurement). This assumes the two have an overlapping region where they can behave well and meet at some point after being trimmed. Some experimentation will still be in order.
 
On the surface, the less duplication there is suggests the less difference it will make.. and there obviously isn't too much or they might(?) not have been made that way.. but when you listen to a woofer on its own without a filter they typically have an edge to the sound, gaps and peaks at the top end where the cone isn't operating as satisfactorily as it should, before dropping off.

Adding a filter can trim this, adding a controlled rolloff while limiting the bandwidth. Using the same coil/capacitor combination for both woofer and tweeter is a reasonable choice for a random assignment (without measurement). This assumes the two have an overlapping region where they can behave well and meet at some point after being trimmed. Some experimentation will still be in order.



Thank you so much, Allen B. You have actually helped a great deal. I am the original owner of the M7 from the late 80's and always felt/heard these speakers had more high's but when I modified the crossover I thought I could hear a big difference. Recently I set the M7 speakers to my Denon DRA-325R stereo as B speakers; put them about 5 feet above the A speakers(Mirage FRx 3's which I used to replace some older B & W V201's that seemed to have more than normal bass but that's another story) on top of the entertainment center facing up about 2 ft or less from the ceiling and I heard a lot more from the M7's which don't have as much bass as the A's but when played by themselves the sound was great on a Kitaro CD. I was modestly impressed! When both A & B play the room is full sound.
Thanks again for the Information, Allen. I appreciate it immensely.
 
Thanks Allen very well written introduction to custom cross-over designing!

Curious about your personal thoughts about high quality active systems without vs (high quality passive with crossover. I am hesitating betwee using active or passive for my custom 3-way project, using a high quality 3-way active crossover feeding my existing 3 Sony 80es amps, then from there directly going to various speaker drivers 4 / 8 ohms. That way completely avoiding the tidious/difficult proces of crossover designing. At the moment I am htinking about the following question:

Why would someone prefer a passive system over active system (given the fact and context when there are multiple high quality amplifiers and active crossovers already at hand)? So is there a acoustic BENEFIT in using passive vs active system? Thanks!
 
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In the hands of a competent designer I feel there is no difference.

If you have the gear, active can give quick results, if you don't then passive can give quick results, but this is not what good crossover design is about either way. The tedium is the learning process, either way, but you'll find many have gone there before and can help.

Personally (and this is relatively insignificant and based on preference), I also design amplifiers. I concern myself with the active stages I put in my chain. I use two stereo amps for my main speakers in a combination of the above but I favour passive.. some at line level and some at speaker level.
 
I have just started reading this thread to help me design a crossover for my project . If I have 2 woofers in parallel do I treat them as 1 4ohm woofer ? I'm looking at flattening the impedance . Or do I use a resistor and capacitor on each one ? Connect them in parallel and add the inductor after ? I'm using scanspeak 22w/8857/t00 . I was thinking of cutting them off around 2k where they dip .
 
You can parallel the two 8ohms drivers and then treat the combination as if it had a 4ohms impedance, i.e. design the Low Pass Filter to feed a 4ohms load.
But that will need big heavy and expensive filtering components.

You may find it cheaper and easier to make the Power Amplifier and the Bass Drivers an active combination.