Axiom Home Page Forums General Discussion Home Theater HT Report and Pics

Hello BigWill,

Hope you are well. Glad to hear that the QS8s sound OK with an 80Hz crossover. I have not heard them, and was just going by the specs. If the receiver can't do channels specific, then I agree with 80Hz all around.

Later,

TonyM

les- thanks for the post and pics.. i cant wait til i get into the HD market.. i am still a few years away.

bigjohn

I will try an 80Hz xover this evening and report back.

If a subwoofer cross is set at 80Hz and applies to the main speakers, setting QS8s at 100Hz cross individually will do nothing.
The sub will not play 'surround bass' up to the 100Hz mark in place of the QS8s as it conflicts with the cross for the mains at 80Hz. In a simultaneous passage with both notes, you would require 2 subs, one to fill in the low end of the mains and one to fill in the low end of the surrounds in order to accomodate such a setup.

However, think about how little bass, especially lower than 80Hz, is really being sent to the surround speakers. Audio engineers know that most surround speakers are not even remotely capable of hitting such notes and nor should they be. Such is the point of owning a subwoofer that recreates the low frequency non-directional sound. This is not the purpose of surround speakers.

I think too many people are concerned about this non-issue of having their surround speakers roll off before 80Hz or earlier (based on specs). Consumers will never get those 11 pound QS8s to make any reasonable SPL for low frequencies. Even if they did, they would not know whether the subwoofer or the QS8s were making them as low frequency notes are essentially NON-directional.

Hello Chesseroo,

Hope you are well.

If using a Harman/Kardon with channel specific bass control you disable the crossover in the subwoofer and use the bass management in the receiver, this allows you to have different crossovers for different channels, as long as you have your subwoofer amp's crossover disabled or dialed to its highest setting. AVR630 has front/center/surround/surround back specific crossover settings, instead of one universal setting.

So, you can have your large M80's set to 60Hz, your center at 80Hz, and your surrounds at 100Hz if you wish, and the receiver will send the signals below those settings for all channels to one subwoofer.

I am not familiar with the Denon's bass management, I can only comment on what the H/K is capable of.

Unfortunately 100Hz is the threshold for directionality, therefore the reason most people recommend 80Hz or lower for the crossover.

Later,

TonyM

Ken has mentioned the HK's crossover capabilities in a couple of other posts, and I've been envious ever since. Does anyone know whether Harmon Kardon is the only manufacturer that offers this feature at a reasonable (<$1300) price point?

Hello dmn23,

Hope you are well. I am not sure what other manufacturers have channel specific bass crossover settings. If anyone knows of some, please chime in here, I would also like to know.

Later,

TonyM

Tony, i understand what the receiver is doing with individual crossovers. What i'm saying is that it doesn't make any sense. The point of a crossover is integration with the whole system (either within a 5.1 setup or within individual speakers).

Having the same subwoofer perform duties with multiple crossovers defeats the point of setting a crossover. Incidentally the 80Hz mark is based on the recommendation as a standard set by THX guidelines (JohnK has posted previously links on this).

Think of it in a different perspective, what if the single bass driver on the M60 had 3 crossover points? How well do you think it would function with the midrange drivers?

Per my previous post example, if the QS8 had a 99Hz note to play at the same time as the M60 had a 79Hz note to play with the crossovers set at 2 different values (80Hz mains and 100Hz surrounds), the subwoofer will still play BOTH notes at the same time.
Since you would still hear the 99Hz note which is beyond the mains crossover of 80Hz, then what was the point of setting a crossover for 80Hz? The subwoofer is not being imited at all.
Hence this defeats the point of using an 80Hz cross for the mains as the subwoofer plays the 99Hz note at the same time regardless. You may as well have had a crossover of 100Hz for the mains because you will still hear that non-directional 99Hz sound.
One speaker cannot play dual roles in this regard.
It just doesn't make physical sense.

Now if you had 2 distinct subwoofers, one specifically setup to run with the surround channels at a specific cross point and one for the mains at a specfiic cross point, then this system setup becomes more logical and possibly useful.
Again, very little heavy bass information should be encoded for surround speakers. Audio engineers know that is the point (and capability) of the subwoofer.

I disagree. Since surrounds have the bass less often than mains do, AND the surrounds (in my case at least) can't reproduce below 100 Hz well, it makes sense to cross them higher than the mains. That way, most of the time, the bass is non-directional, and occasionally, it's above 80 Hz and potentially directional.

Oh fine. Larry posts perfectly lovely pictures and an insightful report on his fabulous new HT and you guys hijack his thread into the ether of surround sound crossover theory. Jeesh.

Larry, very nice, indeed Is your wife happy? Are you?

Thanks for sharing!