# Full range and Sub



## Wull (Apr 7, 2010)

Hi.

I have been running a few REW sweeps this weekend to see what my bass response is like from my sub.

Now I have got to the point where I would like to see how my sub interacts with my main speakers. I have the sub's crossover set to 120hz, and my main speakers are set to 80hz in my processor. When I run my main speakers with the sub, do I set these to large in my processor so there is no crossover, and set the speaker type to full range in the REW preferences?

Or do I just extend the cutoff in the Target Defaults Subwoofer?


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## JohnM (Apr 11, 2006)

The 'sub crossover' is probably the low pass filter for the LFE channel, the bass management crossover will be the figure that is set for your speakers, 80Hz. To see how the sub and main work together you need to leave the mains set to 'small' with the 80Hz crossover. When you are doing that then 'full range' is the correct target setting, since the combination of sub and main should produce an overall flat response (in an ideal world anyway, far from that is the real world of course )


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## Wull (Apr 7, 2010)

Thanks John, understood.


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## Wull (Apr 7, 2010)

OK, only just had chance to run some quick sweeps. 

What I have is a front and rear IB install.

Pic:

1. Font and rear IB.
2. Front and rear IB, phased reversed on rear IB.
3. Front and rear IB, phased reversed on rear IB, main's set to 80hz
4. Front and rear IB, phased reversed on rear IB. main's set to 120hz
5. Front and rear IB, phased reversed on rear IB. main's set to 160hz


Any thoughts on what is happening, and what I could try?


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## Wayne A. Pflughaupt (Apr 13, 2006)

If you’re interested in your subwoofer frequency response (as noted in your opening post), then frequency response graphs would be the best to show us, not waterfalls.




Wull said:


> Any thoughts on what is happening, and what I could try?


What are you trying to accomplish?

Regards, 
Wayne


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## Wull (Apr 7, 2010)

Hi Wayne.

Sorry, as usual I am not making myself very clear. I have recently added a second IB install to help smooth out the bass responce in my room, this second IB has been positioned at the rear of my room.

Having 'quckly' run REW it seems that reversing the phase on the rear IB gives best results when run with the front, please note I have used an Audyssey sub pro for EQ.

I am now looking at how my main speakers interact with the IB's, having run a few sweeps last night it looks to me as if there is a dip being created around 45hz when my main's crossover is left to 80hz, as I increase the crossover this gets less.

Is this normal, if not what could I do to improve this do you think?

Thanks.

Will


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## Wull (Apr 7, 2010)

OK, I have reversed the front IB's phase, and reverted the rear. This seems to have given me a better response...

1st plot, Sub's front and back EQ'd with Audyssey.

2nd plot, Sub's and main speakers.


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## Wayne A. Pflughaupt (Apr 13, 2006)

I see what you mean about the 45 Hz null when the mains are added. Do you have the capability of running different crossover frequencies for the sub vs. the mains?

Regards, 
Wayne


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## Wull (Apr 7, 2010)

Wayne A. Pflughaupt said:


> I see what you mean about the 45 Hz null when the mains are added. Do you have the capability of running different crossover frequencies for the sub vs. the mains?
> 
> Regards,
> Wayne


Yes Wayne, I can, I'll try adjusting the mains crossover up a bit next time. I also noticed when I extend the time delay for my main speakers this moves the null, is this a good thing to try, or should I stick to adjusting the hz range?



Another thing I noticed today when running a few sweeps for my mains, the in inconsistency of the frequency response. Can a build up in room pressure do this? I have yet to confirm as I got dragged away, but it seemed every time I went out of the room, then came back in things changed 'for the worse'?


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## Wayne A. Pflughaupt (Apr 13, 2006)

Wull said:


> Yes Wayne, I can, I'll try adjusting the mains crossover up a bit next time. I also noticed when I extend the time delay for my main speakers this moves the null, is this a good thing to try, or should I stick to adjusting the hz range?


Either method is viable. Crossovers introduce phase anomalies, as does poor time alignment of the drivers. 




> Another thing I noticed today when running a few sweeps for my mains, the in inconsistency of the frequency response.


The room affects the mains, too especially below ~ 500 Hz.

Regards, 
Wayne


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## Wull (Apr 7, 2010)

Tonight whilst just checking my Main speakers response, having calibrated the SPL, then carried out a sweep, when I go into the EQ, set target level then 'match response to target' I seem to always get 'your target level is 80% below etc'

Is there something I am doing wrong?


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## Wayne A. Pflughaupt (Apr 13, 2006)

Can’t say for sure without seeing a graph, but I expect that after a sweep, the trace is way higher than the Target. You can simply re-align the Target to a good mid-way point between the works peaks and valleys shown in your response graph.

Regards, 
Wayne


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## Wull (Apr 7, 2010)

Here's one I have just done.

I am running from 80hz - 300hz. Now I noticed that when I ran from 40hz - 300hz, I didn't get the '88% response of the match range is below etc' warning.

The reason I am running from 80hz up is I have my main's crossed over there. Should I be starting from lower?


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