Crossover/Phase

[imported_LoKe]

I've been looking at by sub, and there are two toggled on the back as well as a knob. The toggles are:

Crossover Bypass: In/Out
Phase: 0*/180*

And the knob is:

Crossover Frequency: 35Hz - 150Hz

Now...I'm wondering...What do these do, and what should I have them set as?

 

[coaster831]

In this case, the crossover controls a low-pass filter that determines whether the woofer will see the full range signal or not. If your sub was fed a full range signal (10Hz-20kHz), and you had the crossover bypassed, the sub would try and reproduce the entire freq. spectrum, essentially wasting your amplifier's power and causing you to lose headroom.

If your receiver has a crossover or low pass filter already enabled for the sub output, you would want to bypass your sub's crossover (or vice versa), because you don't want to filter the signal twice (the receiver is taking care of it).

The crossover frequency comes into play if the sub's crossover is not bypassed. It determines at what frequency the filtering should begin. For example, if you set the crossover freq to 100 Hz, the sub will only reproduce frequencies below 100 Hz (this is sort of misleading, because the crossover point isn't a brick wall so there will be response above 100 Hz, but don't worry about that for this discussion). You'll probably just want to set this by ear. If your L/R front channels can reproduce low frequencies well, you'll probably set the crossover freq lower than if you have small, tinny front speakers that don't get down as far. Ideally, you would have pretty good front channels, so you can set the x-over freq lower, so the signals produced by the sub become less directional (the lower the frequency, the more omnidirectional signals become, making it tougher to localize the source- which is a good thing in a subwoofer's case, since it allows you to put the sub anywhere in the room without feeling the bass is coming from a different direction than the mid/high frequencies). It also allows your sub amp to act more efficiently, since it doesn't have to amplify those extra higher freqs.

The phase control is more difficult to explain, but it's role is to allow you to put the sub in different locations in the room and adjust the phase of the sub to match the phase of the front channels. Basically, set it by ear (at your favorite listening point!) to whatever sounds best (i.e. usually the most bass) to you.

 

[imported_LoKe]

So since I have a nice pair of Paradigm 7's for my fronts, a lower frequency shouldn't be a problem?

 

[biggestmuff]

How is your receiver set?

In your case I'd set the receiver for "Large" front speakers (you don't mention a center channel) and set the sub crossover at 80 Hz.

Then on the sub set the Crossover Bypass to "Out", Phase to "0" and even though the sub's crossover is turned off, I'd rotate the Crossover Frequency knob fully clockwise to 150 Hz.

I get the impression that you've had you equipment setup like this for a while now. I'm curious why you didn't read the user's manual or ask this question when you set up your system? How did you have it setup?

 

[imported_LoKe]

Originally posted by: biggestmuff
In your case I'd set the receiver for "Large" front speakers

Yep, that's how I have it now.

Originally posted by: biggestmuff (you don't mention a center channel) and set the sub crossover at 80 Hz.

I've got a CC170 for a center, as well as 3SE's for rears.

Originally posted by: biggestmuff
Then on the sub set the Crossover Bypass to "Out", Phase to "0" and even though the sub's crossover is turned off, I'd rotate the Crossover Frequency knob fully clockwise to 150 Hz.

Will do!

Originally posted by: biggestmuff
I get the impression that you've had you equipment setup like this for a while now. I'm curious why you didn't read the user's manual or ask this question when you set up your system? How did you have it setup?

I set it up myself, and I had everything set up to work. My movies sound great, music sounds great, but I was wondering if there was "more" I cold get out of it. I never really paid any attention to what the sub on its own was capable of (I screwed with everything through the receiver only [Yamaha HTR5830]).

I bought the sub (Cerwin Vega) off someone I know and there was no manual for it.

 

[spidey07]

Don't set your fronts to large. You'll get much better bass and won't have so many phase/response problems. Set them to small and let the sub do what it's supposed to, produce bass.

If your sub can't produce the bass you want, set your receivers crossover to something lower like 60 hz and set the fronts to large. But this normally gives the impression of "more bass" when it's not. Pick up a SPL meter and try different ways that work best.

 

[Tiamat]

Originally posted by: LoKe
I've been looking at by sub, and there are two toggled on the back as well as a knob. The toggles are:

Crossover Bypass: In/Out
Phase: 0*/180*

And the knob is:

Crossover Frequency: 35Hz - 150Hz

Now...I'm wondering...What do these do, and what should I have them set as?

Since you have Monitor 7's if you were running your system without bass management you would place the crossover roughly at the frequency where your Monitor 7's are -3dB at (usually says in the owners manual).

If you are using the receiver's bass management, set the crossover within the receiver to the lowest setting (probably 60hz or 80hz) then set the crossover bypass to In as I believe that means that "the subwoofer's crossover will be bypassed" which is what you want if you are using the receiver to manage your bass.

When the bypass is set correctly, the crossover frequency knob does nothing.

Phase is pretty important. The general guide without getting into specifics is to set the phase in the position where the bass sounds loudest at your seating position. This means that the subwoofer is in phase at the crossover frequency with your speakers at your listening position.

Edit:
Just make sure you know what In/Out is for the bypass. I certainly dont know, but if you max out the crossover on the subwoofer plate amp, and set the amplifier's crossover, you will tell a difference if you place your ear near your subwoofer when pressing or depressing the button. You obviously select the setting that gives you less high frequency output in this setup.

 

[WaTaGuMp]

Originally posted by: spidey07
Don't set your fronts to large. You'll get much better bass and won't have so many phase/response problems. Set them to small and let the sub do what it's supposed to, produce bass.

If your sub can't produce the bass you want, set your receivers crossover to something lower like 60 hz and set the fronts to large. But this normally gives the impression of "more bass" when it's not. Pick up a SPL meter and try different ways that work best.

Agreed, you use small since the drivers are not bigger then 8"