House Curves - what is your take?

[AudioExplorations]

Is anyone using a 'house curve'? Is a ruler flat curve the ideal?

I have seen a few examples, below with links.

I have tried the 6dB shelved bass curved below (layered on top of the 2 parametric EQ filters I use to flatten out a problematic room node) and I have to say the added bass weight sounds great and gets me closer to the sound of live music.

http://redspade-audio.blogspot.com/2011/06/why-your-system-needs-target-curve.html

B&K House Curve

http://www.bksv.com/doc/17-197.pdf
http://www.computeraudiophile.com/b...-way-it-was-intended-be-reproduced-part-4-47/

 

[audioguy]

Is anyone using a 'house curve'? Is a ruler flat curve the ideal?

A house curve of some type can adjust for the way the ear/brain works at lower volumes.

A number of preamp or pre-processor products on the market have built in provisions for that problem (two that I am aware of are TacT audio and any product with Audyssey X-32). It is usually called something like "dynamic EQ". It certainly seems beneficial for movies. Not a lot of people like it for music.

I do have a "house curve" for music but the bass in mine is nowhere near as jacked up as in your example -- more like 2 to 3 db's. For movies, since no one knows exactly what an explosion sounds like, I jack it up a bit more --- and sometime even more than a bit, more in the range of your example.

I once tired a curve like your second example and it was not pleasant -- VERY dead sounding.

But that's just me!!

 

[GaryProtein]

A house curve of some type can adjust for the way the ear/brain works at lower volumes.

A number of preamp or pre-processor products on the market have built in provisions for that problem (two that I am aware of are TacT audio and any product with Audyssey X-32). It is usually called something like "dynamic EQ". It certainly seems beneficial for movies. Not a lot of people like it for music. . . . .

That used to be taken care of by the LOUDNESS switch which added bass and a little treble at low volumes.

You rarely see that today, and probably never on high end equipment.

 

[Robh3606]

I run my HT/Stereo set up with a curve similar to the first posted. I like the weight as well. It's sounds a bit anemic flat. I also have the last octave rolled off a bit.

Rob

 

[Soundminded]

IMO because there is such a wide range of spectral balance in recordings and because listening room acoustics affect perceived spectral balance so drastically, there is no one right curve. Sound systems are not engineered to deal with either. It takes a well practiced ear and an equalizer to deal with the first, it would take an entire rethink of speaker design to deal with the second. What's more if you're looking for the same musical tone you hear at a concert hall you're going to have to reproduce its acoustics, they are inherently interlinked.

In the 1960s Edgar Villchur said that his AR speakers had a high end rolloff because that's the FR of concert halls. Wrong answer. I can't say if this performance was his design goal or it was just a way to rationalize limitations of his product. You can't reproduce what is a transient process with a steady state filter. As a result speakers with HF rolloffs sound muted, muffled, indistinct. Those with flat HF response sound clear but shrill. In the listening room, unless you have killed off all reflections, the reflections you hear except from behind you will have no high frequency components at all, the speaker doesn't disperse them in the same direction it radiates at lower frequencies. In the 1980s BBC famously made the same error Villchur made in the 1960s. Same result too. How can a sound system make any claim to accuracy, to high fidelity if it can't reproduce the tone of musical instruments correctly?

 

[DonH50]

I once tired a curve like your second example and it was not pleasant -- VERY dead sounding.

But that's just me!!

The B&K House Curve? It's a 3 dB bass boost and slow fall to -3 dB at 20 kHz; I am surprised that's enough to make it sound "dead" unless there were no HF reflections in the room. Not arguing, just curious as to what you actually used and heard.

 

[edorr]

I jack up low frequency response by about 5db, and go down up to about 5db at the high frequencies in my Trinnov DRC system. Sounds totally natural to me.

 

[audioguy]

The B&K House Curve? It's a 3 dB bass boost and slow fall to -3 dB at 20 kHz; I am surprised that's enough to make it sound "dead" unless there were no HF reflections in the room. Not arguing, just curious as to what you actually used and heard.

My bad. I misread the scale. 5 or 6dbs on the full range would not sound "dead".

 

[Robh3606]

On the B+K curve any know why they picked 2K as the hinge point??

Rob

 

[GaryProtein]

On the B+K curve any know why they picked 2K as the hinge point??

Rob

If the dB levels were 3 dB lower overall, the apparent hinge point would be 630 Hz, the logarithmic center of the ear's spectrum. See the B&K graph.

In actuality, there is no hinge point. It just appears that way because of where the test curve crosses lines on the graph. The "hinge point" is only an artifact.

It looks like they may have set 2000Hz as their zero point for convenience or possibly because 2000Hz is about the ear's most sensitive frequency. ????

 

[AudioExplorations]

If anyone is testing these various settings out, what parametric EQ filter settings are you using?

For the 6dB boost I am getting something close using a low shelf @ 80Hz/+5dB/Q1.0
For the B&K curve something like low shelf @ 63Hz/+3dB/Q0.125 and high shelf @ 20,000Hz/-3dB/Q0.15

This is not generating as straight a line as in the diagram but is getting pretty close with only the 2 filters used.

 

[Wayne A. Pflughaupt]

A house curve is not a means of compensation for the ear’s decreases sensitivity at low volume levels, and has nothing to do with old-school loudness switches (which was a fix of sorts to compensate for the same). Rather, a house curve is compensation for the room. Every room is different so there is no “right” or universal house curve, but generally speaking smaller rooms sound better with a steeper low-end boost, whereas larger rooms can get away with less. A room has to be pretty big before it sounds natural with flat- or virtually-flat response. We’re talking small public auditoriums here.

The goal of a “proper” house curve, IMO, is to have all bass frequencies sound like they’re being generated at the same volume level, irrespective of what response measures. With measured flat response, a 30 Hz sine wave probably won’t sound as loud as one at 80 Hz. A little trick I came up with for determining a suitable house curve for a room is to play a sine wave at the crossover frequency of your subwoofer – 80-90 Hz typically – and a second at 30 Hz or so. If the 30 Hz signal sounds weak compared to the higher one, increase the level of the 30 Hz signal until it sounds like it’s the same volume as the higher frequency signal. At that point, the difference in measured SPL between the two signals is your house curve. E.g., 78 dB measured for the 90 Hz signal and 83 dB for the 30 Hz signal gets you basically a 5-dB slope. At that point, you would want to equalize response reasonably flat so that it slopes up 5 dB from 90 Hz to 30 Hz. The popular Room EQ Wizard program has a function that adds a house curve slope to your target curve for equalizing a subwoofer.

I’ve found that with the proper house curve in place, the only adjustment needed for different volume levels is to basically turn the sub up or down as needed. There’s no reason for a separate “low level” house curve and an “ear-bleeding loud” house curve. As I mentioned, the house curve is compensation for the room, not the ear.

The house curve shown in the first post didn’t sound good in my system. It’s not an upward slope from the high frequencies to the low, but merely an overall volume boost of a sub that’s equalized flat. Still, the main objective is coming up with something you think sounds good in your system. At the end of the day, it's purely subjective.

I wrote a treatise on the topic a number of years ago that might be of interest. I’m not sure if we’re allowed to post links from other forums here, but if you search “house curve” it should come up on the first page of most search engines.

Regards,
Wayne A. Pflughaupt

 

[Soundminded]

I have never heard the term "house curve" before. For me equalizers have several functions. One is to compensate for the FR irregularities of the speaker system itself, another is to adjust for freuency variables in room reflections. The problem here is that for the overwhelming majority of speaker systems, virtually 100% of them, you can't adjust for these independently. That's why I design my own speaker systems or more accurately, I redesign other people's. The other function is to adjust for differences in spectral balance from one recording to another. This is why my sound systems all have at least two equalizers in them. the first one is usually a 10 band and the channels are independently adjustable. The second is either a 7 band with independent control over each channel or a 5 band where one slider adjusts both simultaneously. The 7 band can usually get better result but is very tedious and time consuming to use. The 5 band is usually much faster to use, somewhat less control, but usually satisfactory for the system it's connected to. And the 10 band equalizers, how long does that take? Typically about two years to get it right.

 

[audioguy]

Thanks Wayne. Very enlightening.

 

[AudioExplorations]

Thanks Wayne. Very enlightening.

+1

 

[A.wayne]

Yet another way to make things sound unnatural , the great EQ curve ....

 

[DonH50]

Or more natural...

 

[A.wayne]

Never heard such , it doesn't work , good effects ? yes , to your taste? Yes , natural ,err no...!!!

 

[edorr]

Yet another way to make things sound unnatural , the great EQ curve ....

What are the chances somthing recorded in the Blue Note will sound "natural (i.e. the same as in the Blue Note)" in my 13' x 25' basement through a pair of speakers, without any adjustment to the response curve? This would be a complete crapshoot.

 

[edorr]

Never heard such , it doesn't work , good effects , yes , to your taste , natural ,err no...!!!

It works very well, but you need a totally transparent very good DRC system.