first order slopes

[Professor smith]

whats the benefit of the 1st order slope for multiway speakers? I hear a lot of criticisms about them like lobing and high distortion so why do a small minority of designers still use it? Some very well respected and reviewed speakers use them.

[Jonathan Bright]

There are few areas that have so many "RIGHT" answers as cross-over theory. Interestingly you get 1st order networks used in the cheapest and some of the most expensive designs. So that gives you one reason: low parts count and therefore economical. Now where they are championed for theorectical reasons is for they're minimal phase change at the cross over point.
This is a large area and you may get a lot of responses but it may be best to "google" a search on speaker crossovers and look at a dedicated site. There are just a lot of issues to consider.
I.e. cost, phase, power handling, lobbing, termination (of high level passive networks), overall efficency of the complete system, intermodulation distortion in the amps of active designs etc.
Have fun! To my mind it is a facinationg area to study.
Cheers, Jonathan

Hi PS. Just looked up you profile/stats in the members area......You area man of great faith! You got 149 posts last time you raised the issue......I doubts me the science has advanced all THAT much since you last enquired. Do you have a specific issue you want to address? The Linkwitz site might be a good place to start on theory but while he is a committed 4th order man he is good on the hard science and I learnt a lot from him 30 odd yrs ago. And there are people who want more than 4th order btw........

[Juhleren]

1. order slopes is a two edged sword; on one hand you get more through it, on the other you also get more through it Higher order slopes does more to the signal which has other potential pros and cons. The general rule of thumb is to go with the simplest possible solution as less can and will go wrong that way, but making a crossover is like any other design a compromise where one has to choose between different downsides. Some may prefer the sound of the drivers they use (which comes more through with simpler slopes) and other may prefer the sound of the slopes they use (which is unavoidable with more complicated slopes).

Its like policy, when one issue is addressed a magnitude if other unintended and often unexpected effects are brought to life

Best thing is to play with different filter approaches to get a tacit feel of the matter as theory on this topic doesn´t quite cut it alone or pay it justice either...

best,

[bbggg]

Originally Posted by Professor smith

whats the benefit of the 1st order slope for multiway speakers?

The advantage is rather straightforward to comprehend: with 1st order (6 dB/octave) filters, the outputs of the filtered drivers sum correctly when the listener's ear is equidistant to the acoustic centers of the drivers. This does not happen with higher-order filters.

[chris661]

Some reading here

I believe that article covers the subject of passive crossovers in general pretty well.

Oh, and this may be of some use.

[Professor smith]

i prefer not to read the esp site, it seems biased and so does the linkwitz site.

The advantage is rather straightforward to comprehend: with 1st order (6 dB/octave) filters, the outputs of the filtered drivers sum correctly when the listener's ear is equidistant to the acoustic centers of the drivers.

how is that a benefit? its not straightforward to me.

[bbggg]

Well, professor, Linkwitz's site is invaluable. I'm afraid I cannot help you much more than this.

[tinitus]

you can build a speaker with 1.order

and it may even sound 'ok'
or maybe even quite good
just don't play louder than average SPL
at louder SPL it will distort, and begin to sound unpleasant

might also be a problem with power response
no control

but if you always listen at very low SPL, then you might actually get better sound with the simplest 1.order

[Michael Bean]

1st order crossovers are ideal in theory, until you try to use them in the real world. It's nearly impossible to achieve an actual 1st order slope when you have the natural 2nd order high pass at the low end of the driver response and the cone breakup modes at the upper end. To achieve a true 1st order slope the drivers must be able to reproduce at least 3 octives beyond the intended passband, which means the design would probably need to be at least a 4 or 5 way design. Also the drivers must be time aligned throughout thier respective passbands, which won't be easy due to frequency dependent phase shift in each driver. There are other issues also, as alluded to in prior posts. Sorry to be the voice of reason here, but real 1st order crossovers are extremely difficult to do correctly for pros, nearly impossibe for amateurs.

Mike

[Professor smith]

Sorry to be the voice of reason here, but real 1st order crossovers are extremely difficult to do correctly for pros,

Who has done it correctly?