House curve - Reference Levels - Calibration (1 Viewer)

[Wayne A. Pflughaupt]

Great post, Richard.

I personally do NOT want subjectively flat response to 20Hz. Very few songs have 20Hz musical content so this is almost a moot point .

I didn’t care about it (response to 20Hz) until I expanded my system for home theater. My RTA (connected line-level to my system to “see” actual program content) shows that bass-heavy flicks like U-571 and Lost in Space put out low end all the way down to 25Hz. They may get even lower, but unfortunately my RTA stops at 25Hz (a real bummer).

Regards,

Wayne A. Pflughaupt

 

[Harold_C]

I’ll have to respectively disagree with this one, Harold. Any music source, electronic or acoustic, is going to be influenced by the room’s acoustics, just as the speakers would. Especially a cello, which can hit some pretty low notes.

I agree with that.

I probably didn't make myself clear. What I meant is that the cello is what it is. If it is being played in my living room, the acoustics of my living room will clearly affect the sound. However, for the sake of discussion, the cello is "electrically flat".

Now, if we take a theoretical perfect subwoofer (one that measures dead flat in anechoic free-space and play a theoretically perfect recording of a cello with NO equalization in my living room, it should sound like the cello being played in my room. Both the cello and our theoretically perfect playback system are "electrically flat" and the room acoustics should affect both equally.

If we apply a lot of parametric equalization to correct for room effects to our theoretically flat playback system, the cello recording is going to sound different.

Better? Worse? I dunno. Just different.

The idea behind equalization is to remove the effects of my living room on the sound system. That's a reasonable goal, although I'm not sure that it is achieveable.

 

[brucek]

If we apply a lot of parametric equalization to correct for room effects to our theoretically flat playback system, the cello recording is going to sound different.

Yeah, but that's because most of our HT rooms are not concert halls, and they require compensation of some sort at lower frequencies.

If you played that cello in my HT room that produced a large resonant peak at 70Hz everyone would exclaim, "Man, that cello sounds like crap in here"....

So I record it and play it back with that peak equalized out with a parametric and it sounds great.

I think it is an achievable goal to remove the worst resonances in a room to at least hear reasonably smooth low frequency response.

brucek

 

[Wayne A. Pflughaupt]

Harold,

The idea behind equalization is to remove the effects of my living room on the sound system. That's a reasonable goal, although I'm not sure that it is achievable.

You’re absolutely, right, removing the effects of the room is not possible. Perhaps a more realistic description is “improving” the effects of the room? I think we can all agree that’s achievable.

Of course, the room’s effects aren’t all bad. I actually prefer some reflections and cabin gain to the dry, bass-anemic sound of say, an outdoor system.

As always, Harold, your input is enlightening and thought provoking.

Regards,

Wayne A. Pflughaupt

 

[Harold_C]

If you played that cello in my HT room that produced a large resonant peak at 70Hz everyone would exclaim, "Man, that cello sounds like crap in here"....

Probably.

But, I'm not sure science has really figured out why a great concert hall is a great concert hall. For example, Boston Symphony Hall will just blow you away. Yet, when they built Avery Fisher Hall in New York, using the best acoustics experts in the world to design it, it sounded like doo-doo. It was so bad that they had to basically gut it and start over. I don't know, but if I had to guess, I would guess that Boston Symphony Hall is far from flat...but that, by good fortune, its resonances and reflections just happen to perfectly complement a symphony orchestra.

I agree that you can help tame the worst room problems with a combination of subwoofer placement and equalization. However, trying to define (and measure) the optimum low end frequency response curve? I dunno. I think you would probably get as many opinions on that as there are audio engineers! Heck, speaker designers can't even agree if the midrange should have flat response.... The ear and our perception of sound is a funny thing.

 

[BruceD]

Harold,
I think the point to made here is that for relatively little $$$, a bit of parametric room EQ for the bass is probably a good thing for the vast majority of our home listening rooms.
Getting rid of annoying bass peak(s) that disrupt an otherwise enjoyable sound experience is desirable.
Parametric EQ is simply put the easiest, best WAF, and cheapest way to do it.
It's simply info every HT enthusiast should at least know about, even if they don't want to use it.