First Order Crossovers: Pros and Cons

I'm going to let everyone know when Bill finishes his own Ohms, and then you're all going to have to get into Philly so that we can all go over to HIS house for a bar b que. Believe me, it's going to be an absolute blast.

As Sean stated, Bill's favorite speakers are probably the Ohms. He has told me several times he considers the Ohms the finest speakers ever produced, once he implements his ideas into them. I spotted them once in his shop, and he just lit up. I asked, "But, they sure are hard to drive, aren't they?" His reply was, "No, when I get done with them, they are incredibly sensitive. They'll play like crazy with no power."

No, he hasn't tackled his own yet, as he dreads working on them due to the labor intensity. He just doesn't want to take time away helping you and I via his business. You must know the man in order to understand. When he does something, he does it better than anyone else has ever done, otherwise he just doesn't do it. Last summer, he painted his wife's car, at what he claimed to be twice what a quality body shop would charge. Why? Because it needs to be to his own standards or else he will drive himself crazy, and no one beyond him can meet those standards. If anyone ever wants to see how detail oriented he ever is, just ask him a couple of questions regarding automotive transmissions. You'll get an education the likes of which no one has ever gotten before.

I strongly believe Bill is the finest speaker guy in the country, if not the world. It's amazing who we hold in such high regard in this industry, while failing to recognize the true genius of the craft.

I haven't read this entire thread, but it's not clear that a particular speaker which is or claims to be time and phase coherent will have a simple crossover network with few parts, although that seems to be the case with Meadowlark and Green Mountain.

Vandersteen and Thiel have involved crossover assemblies, for example.

I think the only real problem associated with first order crossovers, meaning the one problem which can't be mitigated by engineering or setup quality, is the off axis lobing. This lobing will exist, but may or may not be bothersome to a particular person in a particular situation....

As for whether the recorded music itself has any time or phase coherence by the time it winds its way through the rest of the recording and playback chain...who knows? I just think Vandersteen 2Ce Sigs are still a great bargain.

Off-Axis Lobing. Sounds ominous. Frankly, I honestly cannot say the "off-axis" response of my GMA's is a whole lot different than on axis. In fact, these babies sound fine dead center; 30 degree's off axis or three rooms removed from the speakers. Sure, the image is deaper dead center, but they sound fine off axis too. Can't begin to tell you how many people have made that observance with my GMA's. I get the "We are in the Den but those speakers sound great" comment. Three rooms removed. Can you elaborate on what said "Off-axis lobes" might sound like, Suits me? I heard the same comment from Bobby at Merlin, but he would not elaborate. Will you? What do "off-Axis Lobes" sound like?

Off-axis lobing causes non-linear frequency response i.e. added peaks and dips at various points along the curve. The more consistent the dispersion characteristics of the drivers as angle of radiation is altered, the less noticeable the lobing will be. The differences in baffle related diffraction also come into play here, so speakers with a more advanced baffle design will suffer less from this also. I haven't seen pictures of all of Roy's speakers, but i do know that he's very aware of baffle related problems and seems to pay attention to such things. Sean
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Suits_me:

You are correct, it is possible to make even first-order crossovers very complex, due to either inherent problems with the particular drivers chosen, or simply an obsessive need to over-engineer the problem in pursuit of a perfectly flat frequency response. This is unfortunately all too common. I used to suffer from it myself, until I learned the virtues of simplicity and elegance in design. :)

All crossovers suffer from lobing in the crossover region, no matter what the slope, but the higher-order crossovers have less overlap, so the lobing occurs over a narrower frequency band. Whether this is less audible due to the smaller bandwidth overlap, or more audible due to the faster rate of change in the lobing pattern and source location with frequency, is still open to debate in my opinion.

D'Appolito (MTM or WMTMW) configurations have a superior lobing pattern (less variation at various angles) than standard one-driver-above-the-other configurations, but only if they are used with odd-order crossovers (first, third, etc.) Concentric drivers eliminate the lobing problem altogether (at least in the M/T crossover region), but at the expense of creating an even bigger problem in another area (modulation of the tweeter output by the midrange cone).

It should also be kept in mind that lobing is essentially a direct-sound-only effect. In other words, it does not significantly affect the in-room power response, so its overall effect on the in-room sound while seated is pretty slight. Unless, of course, you like to do critical listening while continuously standing up and sitting down. In which case maybe you need Ritalin more than a high-order crossover. :)

Drubin: Thanks. I don't have much time anymore, just came across this thread by accident and felt like I could add something useful. I hope.

Best,
Karl