DIY crossover components "starter kit"

[urkain87]

I have been considering buying a loot with crossover-components for diy speaker construction, and thought; hey, I´m probably not the only one who would benefit from a list of practical capasitor, inductor and resistor values.

Like resistors, both caps and coils can be coupled in series and paralell to get different values and the formulas too calculate this is pretty simple. This could reduce the lists length considerably.

A good starting point would mabe be a list for each xo-range, for example:
4ohm: 150-450hz
8ohm: 150-450hz
4ohm: 1500-3500hz
8ohm: 1500-3500hz

I´m not shure which values are most practical and most used.
Mabe some of you can help me make a list?

I think the diy community can benefit from a list like this.

[LineArray]

Maybe coils with multiple taps were fine for
experimenting ...

[urkain87]

Yes, that sounds like a good idea.

Looks like I´m the only one who thinks this is a good idea?


Mabe there is a good digital way too do this? This will however result in a more difficult transition too passive filters. Nice for finding the best xo point though

[Cal Weldon]

I don't know if you can assign values like that as the drivers impedance at the XO point will determine the actual cut off and the natural roll off has to be taken into consideration also so it's not that simple but there are lots of charts out there that give the approximations for value.
I've collected and over-bought over the years so my stash includes:

microfarad caps. Assorted types
1.0
1.5
2.2
3.3
4.0
4.7
6.8
10
22
33
47
100

Coils are assorted mH 22 ga. up to 14 ga.
starting at 0.1 (tiny little things)
right up to 6.7 both air and iron core and some salvaged transformers.

Resistors, ohms
1
2
3
4
5
8
12
16

If you were to buy new today probably around $4-500 worth. There are others with tons more but this works for me when I need to scratch the urge. It's nice not to have to order or go and get them.

[urkain87]

Ahh, thank you. this was the sort of answer i was looking for

The values you list are almost exactly what i anticipated, especially the caps.

I know its not actually easy too assume a range of values like that, but if you start too simulate some xo´s you will see that even with the impedance(curves) taken into consideration there will be certain values that can be used. This is also the reason i chose too list such wide range for the xo points. Natural roll-off characteristics I think can be better solved by choosing "matching" drivers, if not; higher order filtering. This still boils down too a certain range of values.
I think it is possible too make this list. I will purchase a bunch of values quite soon, ill most probably do some experimenting and mabe use this thread too post the results.
More people sharing their experience here will also help too see trends.
Then mabe i can get an end result in the form of a list

[sreten]

Hi,

There are no "standard" values for "standard" situations.
Crossover slopes are acoustic not electrical.

rgds, sreten.

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[urkain87]

Remember, this only has to be like LineArray says: good enough for experimenting.

[kbgl]

I like Cals list. I find that for 2-ways, coils are usually 2 mH or less. Coils in the .10 mH to .4 mH range are often needed for notch filters. Buy the cheap ones. Big caps can be handy and you don't want to use up 6 or 7 caps to make a 200 uf, so having a few large electrolytic caps helps. They are dirt cheap, and save a lot of frustration. Get even more resistor sizes, and quantity. Especially 6 ohms and under. Add some 20s, and a couple 40 ohm to the list.

Tip... Get a marking pen and mark everything so that it can be read without picking it out of the box.

[urkain87]

sreten: thank you for the post, but i dont think you should dismiss this idea just yet. You do have a point saying the filter is "acoustic", but this is not really true, although you can take a practical approach and reason this way.
The electrical filter only interact with the driver impedance, not the driver acoustics; the only thing that makes the driver sound different after adding a filter component are reduced signal strength at certain frequencies. Mabe that is what you meant, if so, your approach is just easier?
I would like some constructive criticism if I´m wrong.

kbgl: Thank you for the post. This is good, wee are now moving in the right direction here. You mention notch filters, I must admit i did not remember those when i started the thread. I am just wondering, how often do you really use those 200uF caps?:P i dont see any use for those, except for filters in the 200hz+- region. Mabe a few really big ones can be an "advanced" package"

[Shaun]

Originally Posted by sreten

There are no "standard" values for "standard" situations.

Yes. I suppose it would be better to talk about Most Commonly Used Values.

Originally Posted by sreten

Crossover slopes are acoustic not electrical.

Very true. A point often missed by newbies. The filters described for crossovers are the final acoustic response, which is the combined response of the electrical circuit and the driver's acoustic response as mounted in the enclosure.

Originally Posted by urkain87

Mabe there is a good digital way too do this?

Yes, there is. SoundEasy (and another software; I don't recall which) has an emulator mode called Digital Filter that enables you to listen to your filter design without building it physically. Needs a multi-channel sound card and multi-channel amplifier (though a stereo setup would be fine for a single 2-way).