# Working at equalizing SVS pcultra with HK.



## Guest (Sep 3, 2006)

This is my tim using REW so I have a zillion questions. I've read just about every thread and the documentation at least 10 times so I dont sound like a complete fool.

First my list of equipment.

H/K 635
Axiom (all v2's) m22's, vp150,qs8's
SVS PC Ultra (tuned at 20 hz with no socks currently)
BDF 2496

Room is 16x20x10 (3200) but it opens up to the back plus has multiple openings on the side "in" the audio space and behind it. Total room is aprox 16x55x10 (8800). The room is my family room that opens up to the kitchen. ITs layed out as follows:

North wall is the 16 foot wall with fireplace. Speakers are on either side. West wall has a double french door poening to a study. Aprox 16 feet south of north wall is mainh listening couch. To either side of couch are sourrounds. Center is up on the fireplace mantle.

aprox 20 feet back on west wall bar area juts out. The wall comes east in a little jog 2.5 feet and against this wall is the cannetry for teh wet bar. In this nook is where the sub is placed.

The room then goes farther back and "unjogs" to the kitchen area. After the bar on the west wall is a large opening that is a very wide hallway that opens up to a 2 story atrium area with staircase heading up ect. East wall jogs out before kitchen to an eating area that has windows, sliding door to the porch outside.. its aprox a 5x13 foot area. Round table sits in here and juts out into the larger room. Its kind of like a shallow nook.

Kitchen is U shaped built up in the far south wall. Island, ect. Room is all hardwood/palster. Kitchen has hardwood cabnetry/granite. I have a Large persian with thick padding underneath that covers most of the floor in the "family" area. There are windows with wood binds scattered throughout. 1 sofa, some leather ottomans, 2 overstuffed chairs.

This is not my main listening room and has some sonic problems being that I cant treat it (Wife) and the surfaces are so hard. The goal with the BDF is to jsut do what I can 

This first graph shows the sub ONLY after I have already run teh H/K inboard EQ. Subs gain is set at aprox 1/3rd, and teh HK has backed the db of the sub off at -3db.










You can see the 2 proposed filters.

After Applying the filters i get:










Ok here come the first of my questions 

1) The "curve" I'm using is the default one that comes with REW. It is flat then slowly rolls off. Is this optimal?
2) I eventually want to use the hosue curve method that was mentioned in the stickied thready. First step is to equalize as flat as possible. I assume thats what I'm doing with the curve in step one?
3) The area between 20 and 30 hz is a mess. There are 2 -5db dips there. How do I go about trying to get rid of those? I've read that perhaps I shoudl turn up the gain. That presents the followjng questions if this is true:

a) Turn up the gain in H/K thats currently set at -3db (to perhaps 0 or 2db?)
b) Turn Up the gain on the sub itself?
c) I measured at 75db. During this process when you calibrate You turn teh reciever up to what in essance is a 75 db pink noise signal. If I adjust the gain in a or b all thats going to hapen is that when I turn up the reciever in c its just not going to have to be turned up as loud?
d) Shoudl I measure at a 80db reference level? Ho does this help?
e) I had my reciever for the 75db set at aprox -5 on teh volume control. From personal experience thats ear puncturing loud if I had my mains on. I think the reciever only goes to +10. Is there enough headroom here?

As you can see i'm very confused over issue 3 

I actually have a ton more questions but I need to get these resolved before I can proceed and ask them 

Thanks much in advance for your time.


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## Guest (Sep 3, 2006)

I just realized the sales on my graphs are slightly off. I appologize for that. I thought I saved them correctly but I must not of. Next tim I'll make sure they are correct.


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## eddthompson (Aug 19, 2006)

1) not sure
2) i put in the basic house curve straight away 
3) try a bit of gain at these frequencies, 5db should be ok, if the curves are still there, they probably wont go away, try moving the sub.



a)/b) it sometimes helps to turn the gain up in the amp and turn down the gain on the sub to give the bfd a higher level to work with. it wont help with the dips though.
c) correct you wont need the main voulme as high, this will also raise the volume of the sub compared to the mains, so check with an spl meter on the maps test tones, i find on these, my sub ends up between 5-10 db louder then my mains depending on how much base i fancy at the time.
d) 75 or 80, dont think it matters
e) the noises generated are generaly at the -20db point, so as such quieter than you generaly hear on soundtracks etc. i calibrate most things on my amp at the 0db point, which is ear splittingly loud on music or movies.

edd


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## brucek (Apr 11, 2006)

> This first graph shows....


When you post graphs it would be best to use a vertical scale of 45dB-105dB and a horizontal scale of (15 or 20Hz)-200Hz. This way we're all comparing the same graph.. 
Also remove the filter, soundcardcal and microphone cal clutter etc to make it easier to read.......
All we need it a single before and after graph with your target....... 



> 1) The "curve" I'm using is the default one that comes with REW. It is flat then slowly rolls off. Is this optimal?


It is a standard crossover target that will closely match the crossover curve of your receiver as long as you have entered the receivers crossover frequency into REW. There are also provisions in REW to add a housecurve of your own design if you wish. Realize if it involves adding gain to achieve that housecurve target, it will reduce headroom in the BFD and isn't really advised - 5dB gain would be absolute max. Housecurve targets work best when natural gain is achieved through sub placement.



> 2) I eventually want to use the hosue curve method that was mentioned in the stickied thready. First step is to equalize as flat as possible. I assume thats what I'm doing with the curve in step one?


Correct, also see above.



> 3) The area between 20 and 30 hz is a mess. There are 2 -5db dips there. How do I go about trying to get rid of those? I've read that perhaps I shoudl turn up the gain. That presents the followjng questions if this is true:
> a) Turn up the gain in H/K thats currently set at -3db (to perhaps 0 or 2db?)


Fine if it's frequency dependant....



> b) Turn Up the gain on the sub itself?


This would be wholesale gain - it is not frequency dependant.



> c) I measured at 75db. During this process when you calibrate You turn teh reciever up to what in essance is a 75 db pink noise signal. If I adjust the gain in a or b all thats going to hapen is that when I turn up the reciever in c its just not going to have to be turned up as loud?


Yep.



> d) Shoudl I measure at a 80db reference level? Ho does this help?


It won't..... 75dB will be fine.



> I had my reciever for the 75db set at aprox -5 on teh volume control. From personal experience thats ear puncturing loud if I had my mains on. I think the reciever only goes to +10. Is there enough headroom here?


First set up the subwoofer and BFD input and other speaker trim levels before you set any filters in the BFD.
Then calibrate REW and set your BFD filters.
If there was a lot of cutting of peaks entered in the BFD, then readjust the subwoofers amplifiers volume control to match the mains speaker level using the internal test tone of your receiver.

brucek


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## Guest (Sep 4, 2006)

brucek said:


> When you post graphs it would be best to use a vertical scale of 45dB-105dB and a horizontal scale of (15 or 20Hz)-200Hz. This way we're all comparing the same graph..
> Also remove the filter, soundcardcal and microphone cal clutter etc to make it easier to read.......
> All we need it a single before and after graph with your target.......


I'll redo teh graphs when the kids are out of teh house and I have a block of time where its quiet.



> It is a standard crossover target that will closely match the crossover curve of your receiver as long as you have entered the receivers crossover frequency into REW. There are also provisions in REW to add a housecurve of your own design if you wish. Realize if it involves adding gain to achieve that housecurve target, it will reduce headroom in the BFD and isn't really advised - 5dB gain would be absolute max. Housecurve targets work best when natural gain is achieved through sub placement.


Well this is the odd part. The HK is set where the mains are small at 80hz. same with the center and sides. This best fits the speakers themselves. Crossover should therefore be some sort of rolloff past 80. There is a seperate setting for crossover for LFE. I have that set at 120hz. My understanding is that its only for the LFE channel in 5.1. I'm not sure if dropping it to 80 will send the 80+ through the mains or just completely clip it for LFE. I doubt it maters much as I cant imagine there is much +80hz info in an LFE channel. I could be wrong though.

I think REW is set to 80 hz henze the roll. I should double check though.



> Fine if it's frequency dependant....


I dont understand this. If I turn up the gain in the receiver how does this effect the curve? Since the curve is centered on 75DB turning the gain up does nothing for the sub since when I'm only measuring the sub, to get the 75db pink noise I will then turn down the master volume control? All this would seem to do is boost the gain of the sub compared to the mains, but since I'm not measuring the mains here....

I'm confused 



> First set up the subwoofer and BFD input and other speaker trim levels before you set any filters in the BFD.
> Then calibrate REW and set your BFD filters.
> If there was a lot of cutting of peaks entered in the BFD, then readjust the subwoofers amplifiers volume control to match the mains speaker level using the internal test tone of your receiver.
> 
> brucek


I'm trying to understand this.. on the surface it seems simple enough but the more I think about it the more its confusing me.

If I'm calibrating the sub how does the otehr speaker trim levels matter? How do I re-adjust the subwoofer to match the mains off a simple test tone?
I dont see if I'm calibrating the sub to 75dB how I'd ever get the ability to have a house curve since the pink noise tone is an average of all frequencies, and that average is set on on 75db?

Sorry to be such a noob just trying to understand the correct calibration. I've always done it by ear before and I'm really interested in learning it inside and out and the correct way to do it


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## brucek (Apr 11, 2006)

> Crossover should therefore be some sort of rolloff past 80.


If you have the crossover in REW set to 80Hz, then that is what the target represents. An 80Hz crossover doesn't begin past 80Hz, it begins dropping quite a bit before that.



> There is a seperate setting for crossover for LFE. I have that set at 120hz.


I would set that at 80Hz.



> I dont understand this. If I turn up the gain in the receiver how does this effect the curve?


You discussed HK inboard EQ. I didn't know if it had frequency specific gain settings, so I said it was only OK "if it was frequency dependant".



> If I'm calibrating the sub how does the otehr speaker trim levels matter? How do I re-adjust the subwoofer to match the mains off a simple test tone?


By using your recievers speaker setup test tones and an SPL meter. It's simply a good idea to set the trim levels first to establish the optimum input level to the BFD and subwoofer. See the BFD guide on this setting of BFD input level.
Once you add a few filters, the sub may seem to be too low. You don't want to alter your subwoofer trim at this point, only the subwoofer amplifiers level.



> I dont see if I'm calibrating the sub to 75dB how I'd ever get the ability to have a house curve


Adding a house curve involves using a pulldown in REW to select a txt file you've created that contains your house curve. It alters the target. See the REW Help files to understand how to create the file..

brucek


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