# Custom crossover for each speaker?



## Tevian (Dec 26, 2010)

Hello all. I'm still a total noob on most of this stuff so go easy on me.

I'm building some custom speakers. I have the cabinets are build and I have the speakers. I have simulated the crossover on Xover Pro and I have a simple Dayton testing mic and REQ. I'm starting to understand that simulating and real world results don't necessarily match all the time. Also that it takes a far bit of skill and experience to rectify this. Either of which I have very little. 


My results are not even. I ordered two sets of parts and speakers but the end result is not even on both left and right speaker cabinet when testing with REQ. One cabinet has a 3-4 dB lull at about 2khz. The other is nice and flat. I've double checked my wiring and all seems good to go. I've tested the components to the extent of the equipment that I have. 

I'm aware there are tolerances in speaker and components. How much difference between assembled cabinets should I be expecting? Would it be wise to make a custom crossover for the one side to even out the lull? Resulting in two cabinets with identical speakers but different crossover components in an attempt to reach a flat even response? What might the down sides be? 

Thx guys and gals.


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## robbo266317 (Sep 22, 2008)

Firstly, I would double check the polarity of the drivers, then I would swap the drivers between the cabinets, maybe just the tweeter first, and see if the problem stays with the crossover or follows the drivers. (do the same with the other driver next)
If the drivers are identical then the crossovers should be as well.

Let us know how you get on.

Cheers,
Bill.


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## Tevian (Dec 26, 2010)

Wow how embarrassing! Murphy's law strikes again!

As I was about to pull the rest of my hair out I had a friend go through my wiring. He calmly looked and quickly found the problem. I indeed had one side tweeter inverted on the board side but not the tweeter side. Gees!!

:rolleyesno::rolleyesno::rolleyesno::rolleyesno::sneeky:

Now I get nearly identical results on both sides. Anyway..

About my question... I've been messing with small electronics for a while now. When I make simple circuits I use ohms law to determine the correct parts needed to complete the circuit. Now it occurred to me that because of the tolerances in component manufacturing and the variables involved in speaker making. Would it not be possible to compensate each assembly with an appropriated component arraignment. 

If you had two sets of speaker components and assembled them into a cabinet. Would you not want to create a crossover that takes into an account the individual speaker components by testing each speaker and making choices that match that speaker and not the system as a whole? I know you could just buy a batch of speakers and hand test and match in pairs. But why? Couldn't you achieve a matching result by choosing separate components for each speaker? It makes since to me but I don't have much experience in these matters. For example if I need a specific ohm resister that's not available. I would have to combine two or more to get the value I need. I've seen some crossover construction that uses very specific values and component stacking is used to achieve this. But these choices are always inclusive to the whole system (both left and right cabinets). Why? 

Anyway i'm kinda ranting so I'll stop. 

Thx


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## robbo266317 (Sep 22, 2008)

Drivers should be very similar to each other to not worry about any differences, unless they are very cheap units with little or no quality control.

When you use a set of drivers to make a speaker you should have enough overlap in their frequency responses to make any minor differences negligible. 

eg 








That is from this article here http://www.aperionaudio.com/connect/crossover-design-and-theory/


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## ISLAND1000 (May 2, 2007)

"Tolerances" . . . . realizing that most of our electronics comes from Asia somewhere and they make almost 100% of all the parts ie: speakers, capacitors, inductors, coils, resistors, transformers, etc expect variations in the tolerances. When a component has a 5% tolerance expect 10%. When a component has a 1% tolerance expect 5%.
If a driver has a Fs of 30Hz and another of the same model has an Fs of 37Hz you might want to get a better match. All this tolerance issue depends on your own ear and your own preferences. Much variation between what should be closely matching components but isn't, many times makes no AUDIBLE difference except maybe in volume which is easily rectified.
Unless your work shop contains all the latest in test gear, your ear will be the best test of tolerance. You learned that lesson when you reinverted the wiring in the crossover.


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