# Hard knee house curve for movies



## marty1 (Jun 29, 2010)

I've always aimed for flat response but after reading Wayne's fascinating article on house curves i'm wondering just how much it will add to my sound.

I am a 95% movie watcher so would it be beneficial or not much in it, or will it actually have a negative effect as I did find that initially I had to tame a massive peak at 30hz because it was overpowering the upper frequencies. To look at it, it was pretty much like a house curve response on rew but didn't sound balanced at all.

Im also interested to know by having the lower frequencies high up in db how you avoid room boom as surely the waterfall would show an increase in the time domain.

Lastly, if you are listening to the 30hz and the crossover region to see what slope is required, what if the crossover is in a null like mine?

I would love to hear your feedback before I potentially delve into the eqing world again.

Marty


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## Dwight Angus (Dec 17, 2007)

I am kinda in the same position. My Ht is 90% used for movies & I my volume level is higher then normal with mains sounding bright so I have been trying different house curves to reduce fatigue at higher frequency levels. I am trying a house curve that is linear & reduces db by 10 by 24000hz. So far it sounds great and retains bass impact at low frequency levels. Not sure if 10db is the answer so I will have to try different settings to find the best curve. Very much trial & error.
My 30hz plays at same level as 80hz (within 1db) so by definition the house curve would be flat. I prefer sound with the upper frequency downward slope easier on the ears.
You can move your xo if its in a null. My initial xo was set at 60 hz so I moved it to 80hz to avoid the null. Alternatively you can move your speakers to see if that avoids the null.


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## marty1 (Jun 29, 2010)

I had quite a frustrating time moving the mains around to shift the null but to no avail, the same goes for my crossover, it doesn't seem to shift the null.

Dont get me wrong my system sounds great but you know how it is, you read something and suddenly start thinking 'can I get more improvement out of my system'

I currently have mine flat with a few db gain between 20hz-30hz.

Marty


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

Hey marty,

Many movies exaggerate the lowest frequencies, so a less-severe curve than what's discussed in my articles might work better for movies. There is no time domain issue because anytime you raise the volume – either wholesale or in a specific frequency range - you also increase the decay time. It’s the natural physics of acoustics and nothing to be concerned about. More on that here

Regards, 
Wayne


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## marty1 (Jun 29, 2010)

Hey Wayne,

Thanks, I shall have a read.

I thought that might be the case as I find that the case as even with my slight curve I have in place sometimes the speech can be slightly muddied on certain blurays, like the start of G.I. Joe Retaliation. Any more volume down low would definately tip the balance.

I always believed that when eqing the sub you need to reduce the decay time otherwise the low frequency ringing can affect the clarity of the sound?

I use my bfd to take out 2 issues, a dip at 20hz and a peak at 30hz then I run the antimode to smooth out the overall response which, when you look at the waterfalls you can see it's reduced the ringing and the sound is so nice to the ears, more so than bfd alone, so there must be some positives to reducing the ringing?

Marty


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

marty1 said:


> I always believed that when eqing the sub you need to reduce the decay time otherwise the low frequency ringing can affect the clarity of the sound?


The only ringing you can reduce with an equalizer is that which is caused by a room mode – those peaks at 20 and 30 Hz you mentioned. If you want a real reduction in ringing beyond that, it requires a whole slew of bass traps, more than most people want to put in a room.




> I use my bfd to take out 2 issues, a dip at 20hz and a peak at 30hz then I run the antimode to smooth out the overall response which, when you look at the waterfalls you can see it's *reduced the ringing[/i] and the sound is so nice to the ears, more so than bfd alone, so there must be some positives to reducing the ringing?*


* Smoothing response certainly makes things sound better, but as mentioned at the link in my previous post, don’t confuse the reduced volume levels an equalizer can give you at filtered frequencies with an actual reduction in ringing.

Regards, 
Wayne
*


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## marty1 (Jun 29, 2010)

Just re-read the thread, Thanks for the reminder, i'd forgotten all about that  

Does the antimode just do the same as a bfd only automatically?

I always understood it that there is a bit more to it than just applying filters to cut peaks, I was led to believe that it uses audyssey technology and works in the time domain.

Marty


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

Yes, the Antimode is like an automatic BFD. Any equalizer works in the time domain, but they can’t reduce ringing more than what the room naturally exhibits.

Regards, 
Wayne


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## marty1 (Jun 29, 2010)

Wayne A. Pflughaupt said:


> Yes, the Antimode is like an automatic BFD. Any equalizer works in the time domain, but they can’t reduce ringing more than what the room naturally exhibits.
> 
> Regards,
> Wayne


So literally all the antimode does is apply cuts and bandwidths, nothing more?

So i could be potentially over eq'ing by running the antimode after applying my bfd filters?

Is this all the Audyssey XT32 auto eq in some high end receivers does too?

Marty


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

Yes, from what I’ve seen the Antimode only applies cuts. If you equalize first with the BFD and then run the Antimode – don’t know exactly what it would be _doing_ at that point, since you’ve presumably eliminated the peaks already, but yes I think it would be over-equaling. Sorry, but I don’t know anything about how Audyssey behaves in this specific situation.

Regards, 
Wayne


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## marty1 (Jun 29, 2010)

Wayne A. Pflughaupt said:


> Yes, from what I’ve seen the Antimode only applies cuts. If you equalize first with the BFD and then run the Antimode – don’t know exactly what it would be doing at that point, since you’ve presumably eliminated the peaks already, but yes I think it would be over-equaling. Sorry, but I don’t know anything about how Audyssey behaves in this specific situation.
> 
> Regards,
> Wayne



Okay Thanks Again Wayne


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