Speaker Crossover Modification - 101

While hanging out at the DIY forums we often get questions that go something like this:

I have a pair of (Wharferdale, Focal, Monitor Audio, Harbeth, Audio Research, etc.) speakers and I was wondering if I could upgrade them to get better sound?

The replies themselves go come in a range of suggestions. From don't change anything, to build your own speakers from the ground up.   When considering a crossover modification there are really two general approaches:

• Examine the crossover design and drivers for opportunities of improving the design itself.
• Leave the crossover design in tact but upgrade the parts used.

This blog will show you how to try the second approach and give you a number of suggestions.

If you are not already familiar with the components of crossovers such as capacitors, inductors and resistors, please visit my blog page on the subject, here.

Your Fist Mods

Congratulations, you are now fully informed of all the parts and topics needed to attempt your own modifications.  Your fist mod should focus on the tweeter. You'll replace any caps and resistors with high quality versions with the same electrical values.  Some ground rules:

• Resistors - Replace with same or greater wattage, mandatory.
• Capacitors - Replace with same or greater voltage, but really 100V or greater is overkill unless dealing with high power speakers.  That is, if you have a 600V capacitor, it's safe to replace it with 100V in a speaker if you don't plan on running it with more than 500 Watt amplifiers. 
• Replace all resistors, but only caps in series are required. 

Burn-in Time

It's best to let your caps burn in for at least 48 hours of playing time.  I've heard all sorts of crazy things.  Like the Mundorf MKP's sound great at first, then crappy, then smooth out again.  So I strongly discourage you from rapid fire swapping of the parts. 

Brands

From my own experience, and that of modders I've made these suggestions to there are two brands I really want you to try first. If you can't hear a difference when you make these mods, then at least you know that your ears don't care and you won't join the ranks of those of us spending megabucks on hand crafted capacitors rolled on the thighs of Danish virgins inside a Tibetan monastery.  Be grateful if you can't!

On the other hand, many join us.  The point is, be a scientist.  Experiment on yourself and your speakers and trust your own experience more than mine. Ok, let's get started!

The first combination I'd like you to try is what I call the M&M combo, which is as follows:

• Capacitors - Mundorf MKP  around $5 - $10 each
• Resistors - Mills around $5-$10 each depending on wattage

Please, stick to these brands for your fist mod! This is a tried and true recipe for showing differences between mass-produced crossovers and the sound quality of high quality parts that are not outrageously expensive.

After you have tried this and want to roll your own my advice is to avoid SCR, Axon, and Solen when upgrading film caps. SCR makes so many OEM capacitors if you try to substitute a Solen for an original film cap you could very well be substituting one SCR cap for another and wonder why you bothered. 

Alternatives

Once you've tried the M&M combination, and become more curious about the benefits of high quality parts there are several other capacitor brands in the same price range you can experiment with.

• Audyn Q4
• Jantzen Standard
• Clarity ESA