First Order Crossovers: Pros and Cons

I was only quoting from the same source that was cited, since the earlier quote gave an impression that was different than the articles author intended.

Musical realism is the goal of every high end audio designer.

While visiting our local library last week, I heard some symphonic music and immediately thought "that sounds right!"
So I went to see what could sound like an orchestra in a library, and found....a live orchestra practicing in a library!

Each and every design approach has its advantages and its trade-offs. Getting a realistic sound from a system is a complex topic, and a sucessful design is the result of many decisions. The crossover slope is not the sole determining factor in the sound of the speakers. Examining the crossover slope in isolation is impossible outside the digital realm -
you are always introducing variables as the drivers interact and new radiation patterns are established.

I sympathize with the minority given voice on the forums. After all, I am the only manufacturer with Infinite Slope crossovers! I think its important to look at the acoustical wave interference and lobing patterns of the speaker - but since most other companies have no solution to these problems it is seldom talked about except on these forums.

Jeff

I gave the source as an explanation of vector addition. Then since the thread is about 1st-order crossovers, I included a quote that shows the superiority of 1st-order crossovers. There can be no argument with that. "It yields a piece of wire."

You might argue that some drivers won't tolerate 1st-order crossovers. Ok, that's valid. You can then either look for "better" drivers, or you can compromise with a higher-order crossover.

Lobing? If you're looking for certain types of directivity or power response, then that could be a valid concern. I would certainly look with favor upon a high-order L-R crossover for sound reinforcement use, and this is one of the reasons.

There is much concern with flat frequency and power response. I'm a bit skeptical about their importance. (I feel there are other more important problems. Besides that, to paraphrase Pat McGinty, "Once you solve the transient response, power and frequency response fall right into line."

A number of people have suggested ways to test whether phase coherence is audible, and there are indeed studies with conflicting results.

Rane's suggestion of passing a signal through a 4th-order L-R crossover and then summing the output makes sense. (Linkwitz suggests a similar thing.)

But, in order for the test to be valid, we need to play the summed signal via a transducer with no phase distortions of its own.

A panel speaker would seem to be out, since it has widely spaced sources of the same frequency. In the near field, it smears transients.

Speakers with high-order crossovers are out because they're doing the very thing we're trying to test for and there would be no possibility of a control in the experiment.

Speakers approximating a point source, with 1st-order crossovers might be suitable, but I feel the best bet is headphones. It completely removes any phase distortion due to the room as well.

I do plan on performing this test at some point, but at present I can only say that I find the sound of speakers designed to be time and phase correct to be more realistic than those that are not correct.

Looking at this logically, we can say that a speaker that can pass a transient is better than one that can't. We expect the same from other components in the chain.

The compromises needed to build a speaker that will pass transients is where argument arises. That, or the compromise of building a speaker that won't pass transients. :-)

As for "Infinite Slope," I question whether it is beneficial. What is the phase and time behavior like? Don't sharp filters like these ring? Do most drivers actually need such steep slopes? What kind of load does it present to the amplifier?

The NHT Xd would seem to offer more of an "Infinite Slope" than JosephAudio does. :-)

If one is going to go with steep slopes, then the approach taken by DEQX seems attractive. It corrects some of the problems.

As for the intent of the Rane article, for their purposes the high-order L-R alignment is ideal. They sell such crossovers, so their intent was to sell more of them. However, they certainly cannot say "It yields a piece of wire" about their crossovers.

I did not quote out of context, because I did not change the meaning of what I quoted by quoting only it. As for the author's intent, I don't actually care a fig for his intent. The quote I made stands alone.

The rest of the article deals with: "Are 1st-order crossovers more accurate?" "Yes, but..." The author's intent lies within the "Yes, but..."

Would I choose Rane crossovers for sound reinforcement use? You betcha. I wish I had had them. They offer a superior product for that use.

Karl,Roy&Skrivis:SERIES v PARALLEL 1st Order XO, What are the pos&cons of each in a two way and three way system also in a three way what is more important the T&M or the M&W interface?Would a HEIL be suitable for a 1st order tweeter if OX at about 3k with the new PEERLESS 134 HDS NOMEX paper cone? And A BIG THANK YOU GUYS for a great thread.

Thanks,
Ben

There's some disagreement on the benefits of series vs. parallel. I feel series is superior, but I'm not the last word on things. :-)

You can find a fair bit of info on the net about series and parallel crossovers. Rod Elliott has some good info, for example. http://sound.westhost.com/parallel-series.htm

I don't see that you can say that either the W/M or M/T interface is more important. Both will affect the operation of the mid driver, and that's where your ears are most sensitive.

I don't know enough about the Heil to render an opinion, sorry.

As per Skrivis, my own (unsollicited) opinion would be slightly in favour of a series -- IF you can easily get the drivers' electrical parametres VERY close (or near identical). Again, I'm just a hobbyist -- not a professional.

As to the Heil, 3kHz seems quite high -- which model are you using? As I know nothing about the Peerless, I really can't offer an opinion as to that particular match.
However, the Heil is dipole, so are you considering a 3-way with an open baffle mid -- or are you going closed cab after the Heil? If so, getting your system radiation pattern acceptable 3kHz downward could be a bit tricky!

ASAIK, the guy who makes "Heil" speakers crosses his AMT's about two octaves lower onto an upward firing peerless (quite a big unit if I remember correctly...). Frankly speaking the result is excellent down to the peerless: then things get a bit messy BUT that's just my opinion.
Cheers
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