EQed sub, now how do I intergrate it?

**wilsonj** · **06-07-07, 04:16 AM**

Hello,

here is a graph of my sub frequency response, before and after. I am very happy with the result, using a ~15db house curve from 80 to 20. But does anyone have tips on how to integrate this with the rest of the system?

Blue is the un BFD curve.
before and after sub.gif

I only use this system for HT.

Do I measue each L R C speakers seperately. It seems rather difficult to do, as my processor sends different amounts of signals to different speakers depending on what mode it is in. eg Logic7 or DD.

And what sort of full range curve should I be trying to achieve? +-3db? Or is that a little too much to expect (I think it is)

I'm really at a bit of a loss on how to go about this.

Cheers
Jamie

**brucek** · **06-07-07, 08:14 AM**

Quote:

Do I measure each L R C speakers separately. It seems rather difficult to do, as my processor sends different amounts of signals to different speakers depending on what mode it is in.

To measure and test the sub, you likely fed the AUX or CD input of the receiver and had the mains disconnected. You likely used stereo mode, since that mode doesn't use any decoders etc. Use this same mode to integrate the mains.

Simply turn on the mains (you need to feed the AUX or CD input with a 'Y adaptor' to get both mains on). Now measure the sub just as you did when the mains were disconnected. (except be sure to make the end frequency entry into the measurement panel at 200Hz - in your sub graph you cut it a little shorter than that).

Quote:

And what sort of full range curve should I be trying to achieve? +-3db? Or is that a little too much to expect (I think it is)

The level balance between the sub and mains is up to individual taste. Some want to end up with a straight flat response and others want the sub quite a bit higher than the mains. It's up to you. What you do want to look for is how the crossover area looks since the combining of the mains and sub can cause peaks and valleys at the crossover frequency. Usually sub phase control will eliminate this.

The rest of the speakers in the system are simply set to the level of the mains using the receiver test tones routine...

I attach two examples to show you that peoples tastes differ.

The first graph is from a bass nut who has his sub much higher than his mains (but crosses at 60Hz). The nut happens to be me.

The second is from a member here who has the sub and mains flat...

FULL_RANGE_WITH_FILTERS.jpg

brucek

**wilsonj** · **06-07-07, 06:39 PM**

Hi Bruce, thanks for your reply.

OK I did what you said and found the sub was out of phase to start with. BIG dip in the curve. Fixed that and played with the xover points for a while, but not having the perfect placement for my fronts (one is backed into a corner) and no other EQ there is not much else I can do for now.

One other question. What about the centre?? Is there anything I can do for that? I can't run all 3 fronts and sub at once anyway. I guess the only thing I could do is check the phase?

Here is my latest graph. The bump at about 132hz is from the mains, and I can't get rid of it.
subandmains.gif

Cheers
Jamie

**wilsonj** · **06-07-07, 06:44 PM**

Oh the other thing to note is that my house curve has disappeared!! Looks like it was swallowed up by the xover point. But it still sounds very good to me, in fact the bass is almost overpowering at times. Like the knocking of the glass tank scene in Finding Nemo.

**brucek** · **06-07-07, 07:08 PM**

The assumption is that if the sub integrates well with the mains, then the center should be fine.

Your response and integration is very good. Always best to start flat as you've done, and if it sounds good at that point, you're finished...

brucek

**wilsonj** · **06-07-07, 08:17 PM**

I just checked that all my other speakers were in phase, which they were. And I guess that it can be assumed the centre should be the same as the L and R speaker, as you stated. Makes sense to me!

Thanks again for your help. What a great forum!

Cheers
Jamie

**tweakophyte** · **06-16-07, 04:22 PM**

If it ain't broke, don't fix it...

...but...

For others reading this there are few things you can do to integrate the sub and mains. Since you can measure a lot with REW you can play with both phase and x-over. The trick is, instead of playing with the phase dial you can change the sub's distance in set-up options on your reciever.

Before or after that you can play with the x-over frequency.

Again, since the measuring is automated you can tweak to your heart's desire.

**wilsonj** · **06-16-07, 04:42 PM**

Ahhh, another great idea. Hadn't thought of that one!

**tweakophyte** · **06-17-07, 07:31 AM**

Ed Mullen gave me that trick.

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