Question about Quadruple-crossover systems

[JackT]

I spotted this statement in the Denon 5805 review:

"The problem with most multiple crossover systems is when you configure one speaker group's crossover to a much higher setting than the main channels, the bass from those speaker groups don't get recombined to the sub and are lost entirely."

I found this to be alarming. Is it true?? Is this true for the HK multiple crossover system? This feature would be useless if this were true.

A related question: how important is the ability to set independent crossover frequencies? It seems to me to be a very nice feature, but a lot of receivers don't offer it.

 

[jcPanny]

Multiple crossovers

Maybe someone with an HK can try this test. Set the crossover on the center and/or main channels is high as possible and the remaining speakers to a normal 60-80 Hz setting. Is some of the dialog lost or does it get routed to the sub? If the flagship Denon cant do this correctly, then I doubt many other receivers would.

THX and Dolby recommend an 80 Hz crossover and all speakers set to small, making the multiple crossovers unnecessary. If you have floorstander mains or crummy surround speakers then there may be some benefit if the bass management handles the multiple crossovers properly.
For example it your satelite type surrounds only play down to 100 Hz and distort when they try to lower frequencies then there would be a benefit to a higher crossover for the surrounds. However, if you have such underperforming speakers, then you probably don't need a high end receiver with multiple crossovers.

 

[JackT]

That makes sense. That leads to another question: In this world of 80Hz crossover for everything, it seems that when purchasing speakers, one should spend money ONLY on getting optimal performance above 80Hz. (Perfomance below that point would be of no concern.) Is this basically true?

 

[AVRat]

The 80Hz X-over point is just a reccommendation basically for HT. Any speaker should operate optimally in the range it's designed for. M&K for example designs their speakers this way. THX certified speakers are also designed this way. BTW, the subwoofer should then seemlessly handle the lower frequencies so that a fairly flat response is provided by the entire system.

 

[j_garcia]

Your speakers should be chosen so they operate well together. IMO, if you choose surrounds that have a LOT less bass than your mains which requires you to have significantly different x-over points, then you're at fault, not any of the gear.

I use an 80Hz x-over with speakers that can handle that and it works very well.