Axiom Home Page Forums General Discussion Advice from Axiom Owners Subwoofer crossover questions

I decided to start another subwoofer thread. Here are my questions:

If I set my fronts to “small’ on my Denon AVR, the crossover is set to 80 Hz. So, frequencies below 80Hz are sent to the sub.

If I set my fronts to “large” on my Denon AVR, the fronts handle the low frequencies. But how low? What is the new crossover? I’ve been looking through the Denon manual, but can’t find the answer.

How does the sub's crossover switch work? Let’s say I enable it and set the crossover to 60Hz, do all low frequencies get sent to the sub and the crossover setting acts like a “sub traffic cop” and only allows frequencies below 60Hz to be produced?

Another way to look it would be, if I set the fronts to small, the crossover is 80Hz. If I also enable the sub’s crossover and set it at 60Hz, what happens to the frequencies between 60 and 80 Hz? Are they not played?

Does this make sense or am I out in left field?

Thanks

In reply to:

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If I set my fronts to “large” on my Denon AVR, the fronts handle the low frequencies. But how low? What is the new crossover?

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There is no new crossover. Your main speakers will now receive the full frequency range of that recording.

In reply to:

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How does the sub's crossover switch work? Let’s say I enable it and set the crossover to 60Hz, do all low frequencies get sent to the sub and the crossover setting acts like a “sub traffic cop” and only allows frequencies below 60Hz to be produced?

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There's a slope involved, named because if you were to look at a plotted frequency response chart, it would "slope" down. It's a gradual replacement of the frequencies going to your sub or your mains. In other words, 60Hz is the center point, but your sub will get some of the stuff at 70Hz, and a little at 80Hz. Your Mains will still get some frequencies at 50, and maybe even some at 45Hz. (Don't take there frequencies literally; every reciever is different. What's important to know is that it's not a sudden cutoff.)

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If I also enable the sub’s crossover and set it at 60Hz, what happens

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If you're using the crossover on your receiver, you wouldn't use the crossover on your sub too.... you would be doubling up the effect. You want to turn the crossover on the sub off...or, if there's no off switch, turn the crossover frequency as high as it will go on the sub.

In reply to:

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Does this make sense or am I out in left field?

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Not at all! They're common questions!

I have the Denon 2805, and all speakers set to small, with a receiver crossover of 80hz, sub volume 12 o'clock. That seems to work best for me for HT and pure direct music. If you have the receiver at 80hz, you want to turn the subs crossover all the way up, to get it out of the way.

Mark, thanks for the reply. As usual, I need to summarize it back (and ask a few more questions) to make sure I understand this.

1)If I set the fronts to “large” and they now get “the full frequency range of that recording”. What frequencies does the sub get?

2)If I set the sub’s crossover to 60 Hz, I now understand it is not an absolute cutoff number. How does the receiver now the that crossover is set at 60Hz? I thought it was a one-way communication from the receiver (output) to the sub (input)

3)It seems to me I should forget I ever saw a sub crossover switch.

Sorry for the additional questions. I’ve been known to look at things different and ask “odd” questions.

Thanks again

Yes. Forget you ever saw a sub crossover. They are really intended for use with older non-AV receivers. Some of the latest sub intros don't even have a crossover since AV receivers have pretty much taken over.

You just have to get the crossover out of the way by either disabling it or turning it up to the highest possible frequency.

>>1)If I set the fronts to “large” and they now get “the full frequency range of that recording”. What frequencies does the sub get?

Oh, this is an ugly little question and seems to be receiver dependent. On my HK it seems you can specify a mains crossover frequency even if the speakers are in "Large" and the sub will receive everything below that frequency.

The most common thing is that the sub would get nothing from the mains if they were set to large. On the HK you can choose between SUB LF and SUB LF+L/R -- the second setting includes bass from mains (L/R) even if they are set to large.

I guess I could play a movie with a good sub-scene with the fronts set to large and to small to see the difference.

I played a CD with fronts set to large and to small and I didn't hear much of a difference. I assumed the CD didn't have a lot of low frequencies, therefore the results were about the same.

The difference between Large and Small for music is pretty subtle, and I can't hear a difference at all for most movies. The difference isn't really in the deep bass, I *think* it's more around the crossover frequency but not sure.

I haven't even found the right words to describe the different sound, guess I need to read more high end audio mags (or wine tasting reports ).

John, I'll add a few comments. On 3), yes just keep the sub crossover disabled and let your 1802 handle it without interference from the internal sub crossover. As you indicate in 2), if you also use the internal sub crossover the 1802 crossover can't possibly know that, so they might interfere with each other at certain settings.

On 1),if you set the fronts "large" and you have the sub mode on your 1802 at the usual "Norm" setting, the sub would get none of the low bass from the fronts; the fronts would handle it all(and yes, since the M60s have good bass, there might be relatively little difference if the program material doesn't have a lot of very low bass). The sub would get the below 80Hz bass from the center and surrounds if they were set small and if there was any special low frequency effects(.1,LFE)in movies it would also get that during the times that it occurred. If the fronts were set "large" and you set your 1802 sub mode to "+Main" then the sub would also get the below 80Hz bass from the fronts simultaneously with them, not necessarily a good idea.

John, your explanation hepled tremendously. It answered my questions so now I can move on, felling better about the calibration and setup I did.

Thanks again to everyone who chimed in.