Axiom Home Page Forums General Discussion Technical Questions Crossover Calculator

http://ccs.exl.info/calc_cr.html

Link to a neat little sight to help you figure componnet values for that DIY crossover upgrade. The crossover is fundamentally one of the most important (often overlooked) elements in a speakers design. Most manufactueres (including Axiom) use cheap components in the crossover design and upgrading to better higher quality componnets of the same values (you'd be amazed) can drastically improve the sound of an already good sounding speaker. Keep in mind to never do anything you aren't comfortable with...its your investment!

So you're implying that expensive (i.e. not "cheap") crossover components always sound better?

No thanks. I think I'll leave the speaker design to the experts. I'm sure they've gone through many different tests with many different crossover designs and found one that performs well for the price.

I'm sure it's possible to design a better crossover than those included with the Axioms, but why mess with something that ain't broke?

I respect your position. By all means never do anything you don't feel comfortable with. And no, I'm not implying anything, its a scientific fact. When you choose compnents for their value to acheive a certian electrical effect, those with better tolerances will provide you with better performance. Period. Axiom uses an economy of scale to produce speakers of the quality they do for the price. They have to make concessions or the price would be passed on (to you). Yes, you could build an XO using the SAME values but use higher quality Indctures & Caps and get a different (better?) sound. Its all subjective anyway, so do whats best for yourself.

I have read quite a few threads here on the site from Axiom owners who tweaked their M22 XO's and made a great speaker spectacular. Neccesity is the mother of invention, but if you are happy with what you have, thats ok too. )

Clinton,Ian responded a long time ago to this capacitor and inductor myth. The only thing accomplished is wasting money. Engineers design good crossovers using components entirely adequate to meet performance requirements.

I would like to know where you get your information from.

You call it a scientific fact that replacing stock components in a crossover circuit with components of better tolerances (what is tolerance, anyway?) -- even though they have the same values of resistance, capacitance, and inductance -- results in better performance.

I beg to differ. Perhaps you should explain what you mean by tolerances. Do you mean that the given ratings of the components used in the Axiom XOs are off by a significant margin? Do you really think an expensive and overbuilt capacitor will woo the electrical current into sounding better than one engineered specifically to provide a certain Farad rating?

I understand you're just trying to give us some helpful information, but many of us here like to stick to our healthy sense of skepticism until such "tweaks" can indeed be considered scientific facts.

I'm sure you are familiar with the inescapable psychoacoustic side to audiophilia...

pmbuko:
Tolerance is the variable at which an electronic component meets its rated measure, and is identified as a + or - from the rating. If a capacitor has a 25% tolerance (purley for example) from its rated measure then what makes you think it will perform its function in an electrical circuit "as good as" a component that more closely meets its rating? Its not a difficult concept to grasp, and it is based in fact, otherwise the mathematical/physical principals behind all of it might as well be bunk!...

Axion does not "engineer" the individual components used in its XO's, they buy them from manufacturers (and in bulk), and they may or may not be the best component for the job at hand, but they get it done. For example: Iron core inductors are used in many XO's mainly because of their cost, but also because they have very low DC resistance and a small size for their given value. However, iron core inductors are known to introduce more distortion as apposed to foil coils...You can call it "woo" if you like, but some ears can hear the difference...

Its a free country, but the only way that you are ever going to know anything for yourself is to experiment for yourself, otherwise you are going to be taking somebody elses word for what you believe to be true anyway ... )

Where are you getting your parts and are you sure you're buying lower tollerance devices? Partsexpress, for example is selling normal components that any moron can buy from DigiKey or even get free if they call the disties for samples. There's nothing special about their components despite their claims of "audio-grade".

The frequency response of a simple RC lowpass filter is defined by:

1/(2*pi*R*C)

Precision refers to the manufacturing tolerance of the process. A 100 Ohm resistor with a 5% tolerance means that anything +- 5 Ohms from 100 is allowed to be sold and anything more is discarded (or more likely sold as a 10% piece). By swapping the components, you change the frequency response of the filter. Any difference in the sound you hear is due to the fact that the filter is responding to a different frequency.

If you want a steeper negative gain to your filter, you'll have to employ a different circuit, not merely change your frequency response.

If you use a use an inductor with a series resistance of less than 0.6 ohm (enabling more power to the driver because of a lower value of overall series resistance) how does this effect the "overall" sound of the driver?

I appreciate the more scientific explanation, Semi. I was trying to say something similar, but didn't have the knowledge to fill in the gaps in my argument.

So again, slownlo, changing the components in the crossover only changes the frequency of the XO point. This point is readily measurable by feeding test signals through the XO circuit (not individual components).

To state it again, I trust that Axiom engineers have tested and measured their crossovers so that they conform to a level of quality control that allows their speakers to consistently achieve the expected performance.

Your entire argument hinges on the assumption that more precise parts result in a better sound -- when in fact all you're going to get is a different sound due to the fact that the crossover point has changed. Wouldn't you agree that the crossover point that comes with the speaker has been carefully chosen and consistent beyond a detectable level between one speaker and the next?

Loudness, rated in decibels, is a logarithmic scale. You have to double the power to create anything resembling an audible difference in volume. Eeking out an extra fraction of a watt isn't exactly a dramatic change in the face of a logarithmic scale.