What Xover order is better?

[caenot]

I have seen a lot of people suggesting 4th order L-R for Xover. While I don't have an issue with this suggestion, I found that the number of Xover parts gets quite large if you use 4th order --> and if you translate this to Mundorf, Hovland or Crescendo, you are getting a huge bill.

Who is using 2nd order Xovers? Any good results? I have seen some commercial products, but not so sure about Xover order.

[sdclc126]

I'm not sure you should just be asking for a comparison between one crossover design and another, without including what kind of speaker you want to build. Crossover topology is dictated by speaker drivers, enclosure, design goals etc.

Also, it would be good to tell those in the know here if you have any loudspeaker measuring equipment/software and/or crossover design software.

[lndm]

My personal choice is the first order slope. It is the only naturally transient perfect response, but there is a transient perfect second order scheme out there, it requires a little EQ.

The slope is of course a combo of the drivers natural slope and the crossover. The crossover will probably look like a first order on paper but may be completely different. First order is demanding of the drivers. It works for me though.

[AndrewT]

Hi indm,
I thought that single pole (first order) filters were automatically Butterworth.

If this is the case then these do not have excellent transient ability. Although second only to Bessel.

I think you need Bessel to achieve that excellence.

I'm guessing here, but I think you cannot achiveve Bessel with a single pole filter.

[lndm]

I agree Andrew, you can't achieve bessel with a single pole - in theory. I stretch it in practice. With the text book first order, the drivers are down 3dB at the crossover point. I often design a crossover by simulating the tweeter with a capacitor dominating the crossover region, and working the mid/woofer to match phase, and 6dB down points.

I don't think this is standard, but I like it.

P.S., isn't as easy as it sounds

[theChris]

it doens't make too much sense to call 1st order filters by butterworth/bessel/ect... its just not that complex.

filters like bessel and butterworth are actually defined fairly generically mathmatically. its up to the designer to chose what "cutoff" is. for some apps you might choose -3dB, for others -1dB or -10dB.

1st order is great if you can get away with it. but speaker locations and other issues with the speakers themselves always seem to pop up.

[phase_accurate]

1st order is indeed the only "natural" crossover that is transient-perfect per se. But in practice you will end up with a 3rd order (at least !) electro-acoustical transfer function. There are higher-order symmetrical and asymmetrical crossovers possible which are transient perfect - but they have to be active and they have some disadvantages like large overlap, humps (though summing flat) and transitions that are even flatter than those of 1st order crossovers.

If you want the lowest THD, IMD and the least lobing for given drivers you are better off with higher-order crossovers. But they are a no-no if you want transient perfect response. Now you'd have to pick your poison !

Regards

Charles

[sreten]

Originally posted by caenot
I have seen a lot of people suggesting 4th order L-R for Xover. While I don't have an issue with this suggestion, I found that the number of Xover parts gets quite large if you use 4th order --> and if you translate this to Mundorf, Hovland or Crescendo, you are getting a huge bill.
Who is using 2nd order Xovers? Any good results? I have seen some commercial products, but not so sure about Xover order.

Hi,

Acoustic 4th order L-R crossovers do not always use as many parts as you think.

e.g. http://www.zaphaudio.com/audio-speaker17.html

/sreten.

[rabbitz]

I have noticed that B&W have gone for 1st order on the tweeter to mid and tweeter to midwoofer on their 800 series. The development paper makes an interesting read.

[pinkmouse]

There is no best order for crossovers, just like there is no best amplifier or loudspeaker driver. They all have limitations, and you need to understand how and what they do to be able to choose the appropriate one for your use.