Axiom Home Page Forums General Discussion The Water Cooler Crossovers

While working at designing a crossover for my project i have been snooping around at other speaker websites. While at B&W i read about their theory on crossovers. I found it interesting and thought i would share it. Seems they have the same philosophy as axiom I took pictures of my M80 crossover and analyzed it with my new found ,though limited knowledge of crossovers. I truly believe that the less electronics in the path of the signal the better.Anyway if these sorts of things are of interest here is the link. B&W

Any absolute that says less components in the signal pass is better than more(higher order) is dead wrong IMO.

You can see an example as to why less components can be a bad thing even in a 2 way bookshelf speaker shown below

http://www.salksound.com/wp/?p=135

High order crossovers can be really beneficial especially in a floorstander speaker. In a multi-drive speaker high order crossovers are beneficial because you can really fine tune what frequencies the bass, midrange and tweeter play. This is very important for allowing the speaker to have a great on-off axis response,low distortion, dynamic capability with low compression. All the really important stuff as to why you use multiple drivers. Also controlling what the drivers play prevents the speakers impedance from dropping drastically low which would put electronics into shutdown. Steeper roll-offs can really control non-linear distortion like cone-break up which all drivers suffer from but at different frequencies depending on the cone material. One of the main causes of listener fatigue.

Thanks for the link

If you watch the video, more can be done with less ,by using a well designed driver taking advantage of advancements in driver technology. I understand not everyone shares the same views,we are human I dont have any of the issue's you eluded to and yet the M80 is a multi driver unit with a very simple and well though out(aparently) crossover design along with drivers built by axiom to their teams specifications.

I also dissected my HPM 900's and they were to my ears a great speaker and they play the woofer full range with only a crossover for the mids,tweet and super tweet.

I guess a car analogy would be if i have a 10 second street car,would i feel any better if it ran a 9.99 quater mile.Alot of hard work/expense for that extra 10th second. I listen mostly to rock so i am jaded in that sense. I am not a golden ear and i dont listen to bach to see if d minor sounds like it should. I do know that my van halen sounds alot like it sounded in concert 30yrs ago near as i can remember.

Very interesting, Socketman.

The part that was a revelation to me was:



If - like Axiom and some other established loudspeaker manufacturers - you design and manufacture your own drivers, perhaps you don't need to put as many components into the crossover. A greater proportion of the overall loudspeaker objective can be accomplished through the driver design rather than through network design, which can result in a simpler signal path.

Conversely, if you have to buy drivers from an OEM, you don't really have much choice but to design the crossovers to fit the drivers in the context of the overall design philosophy.

I've met Dennis Murphy; I think he's absolutely brilliant. And I don't think that the linked article is necessarily at odds with the idea that there is more than one way to achieve similarly good results.

i kinda used the wrong wording initially. I really dont think there is a right or wrong way depending on the situation.I was not implying that the use of high order crossover's was not necessary in all situations. As a DIY'er using software and measurements i will be employing both 1st and 3rd order topology. I really just felt it was food for thought and worth sharing. Also im sure Mr Murphy knows one helluvalot more about the subject than I.

There are companies that build their own drivers and use simple 1st order networks. There are others that use extremely high quality drive units that use 4th order crossovers. I don't buy into the marketing of B&W.

What it really boils down to is the tradeoffs that are determined in the network order - what parameters are you willing to optimize and others sacrifice.

My M3s have a very simple crossover. Isn't it only 1 capacitor? Or is it only the M2?
Anyhoo. They both sound great.

Chris, it isn't actually a crossover, which would both roll off the low frequency driver above a certain frequency and the high frequency driver below that frequency(the "crossover"). The M3 uses only a high-pass filter on the tweeter with a capacitor to roll off the lows(and a resistor to pad down the efficiency to match the mid-woofer). The mid-woofer has no low-pass filter on it and rolls off the highs "naturally". Works well. By the way, congratulations on the new car.