# Consensus on BFD+Audyssey for house curve?



## JREwing

Noob here, but I've used REW to determine Audyssey has given me a fairly flat response. I've been reading the guides on hard knee house curves and would really like to give it a try. Before I pull the trigger on the BFD 1124P I was hoping to get some input. Seems the consensus is to use the BFD to smooth out peaks before running Audyssey. This would leave me without being able to set a house curve b/c Audyssey is going to flatten everything out. I'm not too concerned about peaks with the sub anyways, Audyssey does a very good job itself.

So what are the downfalls if I run the BFD after Audyssey EQ's everything? I've read a few people felt it would negate the Audyssey results b/c the BFD has fewer filters. Seems like it would be ok b/c if I understand the hard knee house curve you are basically just setting a deep wide filter for one frequency anyways right?

I did find a thread at AVS that touches on the issue, reply #16 is of particular interest. http://www.avsforum.com/avs-vb/showthread.php?t=885535

Quote from reply #16
" I have a house curve from 75db to 80db, what I did was run the 1124 and cut everything down to about 74db. I then ran Audyssey with the eq on. After everything was set, I tooks the cuts out and set my house curve. I believe if you set the house curve before you run Audyssey it may try to cut your curve down to 75db."


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## brucek

> Seems the consensus is to use the BFD to smooth out peaks before running Audyssey


Don't think so....



> So what are the downfalls if I run the BFD after Audyssey EQ's everything? I've read a few people felt it would negate the Audyssey results b/c the BFD has fewer filters.


I don't know what you've been reading, but I think the consensus is to apply BFD filters after the auto setup is done.



> I understand the hard knee house curve you are basically just setting a deep wide filter for one frequency anyways right?


No, it will likely take several if not more filters.

brucek


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## JREwing

Wow ok well apparently I am way off. Thanks for straightening me out here. As long as I can use it to set a house curve after the auto setup w/ MultEQ XT, that would be AWESOME!

I'm rereading the guides and I'm still a little fuzzy, are the filters applied only to the subwoofer? Or are they applied to the main speakers also? If it's just the sub I don't understand how the mains are supposed to be intergrated into the curve?


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## brucek

> are the filters applied only to the subwoofer?


Yes, since the BFD is placed between the receivers (or preamps) sub out jack and the subwoofer.



> If it's just the sub I don't understand how the mains are supposed to be intergrated into the curve?


The mains aren't included in any house curve. The house curve is always applied at frequencies less than the crossover.

brucek


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## atledreier

What implementation of Audyssey do you have? If you have DynamicEQ that will sort the house curve for you.


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## JREwing

brucek said:


> Yes, since the BFD is placed between the receivers (or preamps) sub out jack and the subwoofer.
> 
> 
> The mains aren't included in any house curve. The house curve is always applied at frequencies less than the crossover.
> 
> brucek


Thanks for confirming brucek. So I'll just leave the mains w/ the flat response created by Audyssey EQ. I want to make sure I have the steps correct here, please humor me....

1. Run Auto Setup w/ Audyssey to establish relatively flat response for sub and mains
2. Use AVIA disc to adjust all speakers to same db level (Audyssey tends to set my rears a little high and sub a little low for my taste)
3. Run REW to establish freq curve for sub/mains
4. Adjust filters in BFD to create house curve for SUB

Am I missing anything?

As for the Audyssey version, I have a Denon 2809 w/ MultEQ XT and it does have Dynamic EQ. However as I understand it this does not set a house curve. Dynamic EQ adjusts to maintain the same perceived response at lower volumes. For example it increases surround presence and bass as the volume is lowered to maintain the same EQ curve. The curve it is trying to maintain is not a house curve though. So my goal is too create a house curve that Dynamic EQ will try to maintain as it adjusts. Please correct me if this is wrong.


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## atledreier

The house curve is there to compensate, just like DynamicEQ is. If you're properly calibrated and running at reference you shouldn't need a house curve.


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## brucek

> Am I missing anything?


Nope, seems good....



> Dynamic EQ adjusts to maintain the same perceived response at lower volumes.


a.k.a. house curve.........

brucek


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## JREwing

atledreier said:


> The house curve is there to compensate, just like DynamicEQ is. If you're properly calibrated and running at reference you shouldn't need a house curve.


Ok now you really have me second guessing but I still don't think Dynamic EQ is a subsitute for a house curve. 

With a house curve, lower and higher freq are perceived at the same level. For example at a 75db listening level, the 30 hz is actually at 75db, and 100 hz is actually at 70hz, but both are perceived at 75db.

Onto Dynamic EQ. Dynamic EQ isn't active whatsoever at reference level, it only kicks in as you lower the volume. As you lower volume it increases the lower frequencies so that they still appear to maintain the same 1:1 ratio with the higher frequencies. Apparently this is to compensate for the human ear's diminished perception of lower frequencies as volume decreases (this seems to be a completely seperate issue from how a particular room causes certain frequencies to be perceived as louder than others, aka house curve.) 

So with Dynamic EQ at a 75db listening level, since Audyssey flattens everything out, 30hz is actually 75db and 100hz is actually 75 db (not a house curve). As you turn down the volume lower than reference, lets say 65 db, the 30hz and 100hz frequencies are still heard with the same mix (whereas without Dyn EQ, 30 hz might be perceived as lower.) So since both are heard at the same level (or at least what Audyssey thinks is the same level), it still leaves the 100hz frequency to be perceived louder (according to the house curve theory.) It attempts to return what is perceived back to the original flat curve it started with. So although it helps to at least get back to flat, it doesn't take the next step to compensate for the house curve. And that's what makes me think I still need to adjust for a house curve.


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## JREwing

Anybody else want to chime in on whether I still need a house curve with Dynamic EQ? I'm just not feeling real confident about this.


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## atledreier

DynEQ does make it flat (perceived), which is the point of a house curve as well. If you are calibrated flat and always listen at reference, most peope would have more than enough bass. It's once you turn down the volume you feel the need for a house curve, and that's exactly what DynamicEQ does for you.

If flat with DynEQ isn't enough bass for you, THEN get a house curve. Most reports I've read after getting DynEq is that people think it's a bit on the bass-heavy side. Add a +6dB house curve and you're probably hearing your subs way too loud.


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## JREwing

atledreier said:


> DynEQ does make it flat (perceived), which is the point of a house curve as well. If you are calibrated flat and always listen at reference, most peope would have more than enough bass. It's once you turn down the volume you feel the need for a house curve, and that's exactly what DynamicEQ does for you.
> 
> If flat with DynEQ isn't enough bass for you, THEN get a house curve. Most reports I've read after getting DynEq is that people think it's a bit on the bass-heavy side. Add a +6dB house curve and you're probably hearing your subs way too loud.


Thanks for the input. I am happy with the amount of bass, but it's rather boomy in the mid bass region, so I was hoping a house curve might help tone that down. I guess I'll just some time and see if I like the sound of Dynamic EQ. Thanks again.


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## morik

I know this is a really old thread, but I have some questions I think are relevant here.

I have an onkyo 3008, which has Audyssey Multi EQ XT32.

I just ordered a BFD1124P.

I plan to use the BFD first to smooth out some room modes that Audyssey doesn't seem to be able to get (according to REW measurements).

I was planning to do that with some set of filters, run Audyssey with the filters on, and then adjust with further filters for a house curve as needed. However, reading this thread and a few others, it sounds like dynamic EQ will handle the house curve for me. And I have the option of setting the reference level to either 0db (film), 5db, 10db, or 15db. I'm guessing some of the comments in this older thread about dynamic eq being too bass heavy were from when it was stuck at 0db... that indeed makes music too bass heavy for me. The manual recommends -5 for classical, -10 for jazz/some other types, and -15 for rock/pop. I find -10 to be pretty good for most music I listen to though (metal, rock, etc.)

With audyssey on, but dynamic eq off, a 30hz tone is not nearly as loud as a 100hz tone. I will have to test with dynamic eq on at different reference level settings (0/5/10/15) to see what heppens... I've also been calibrating at a 75db SPL, but should probably be going more like 85... hard for me to tell since I listen at anywhere from 75 to 95 db depending on time of day/movie vs music, etc. Or maybe I don't need to worry about it with dynamic eq? (I guess I can find out with testing perceived loudness at various levels with dynamic eq on... I'll test that as well)


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## morik

Looks like dynamic EQ does take care of a house curve itself.

These were taken with a receiver volume of -36db (offset from THX reference), which corresponds to REW showing 75 dbC during the check levels.

Looks like compensation started out around 150 though, and gradually grew for a little while, then spiked up at 70, where it just rose slightly after that...

Testing 30hz vs 100hz, just did a quick test. 100hz @ -36 sounded about as loud as 30hz @ -26... can that be right? (This was with the 0 offset, so the grey line above)
The difference should already have been about 15db... really need a 25db boost? (I may just be wrong... its kind of hard for me to judge the loudness of the 30hz signal, as it sounds so different. I found the 60hz to need maybe 5db to sound about as loud as the 100...

So should I tame peaks, run audyssey, then apply a steeper low-end curve using the 1124?
I do notice in music that the 0db offset sounds too bass heavy, while the -10 offset (blue line) sounds about right. (Though I listen with the receiver volume set much higher than -36...)


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