Question i can't find the answer to

[SAHSU]

I see all these charts online from people running frequency response measurements of their equipment. Almost all of them reside in the 75-85dB range as the average level they're trying to reach with each frequency.

My question is why this range? If someone (especially for subwoofers in a media room) is really interested in what their equipment can do at high SPL with lots of boom and bang and rumble, then why don't they test to see how even their responses are at the louder levels? 100dB or more?

[cschang]

Have you listenned to your speakers at that high of an SPL?

[SAHSU]

Have you listenned to your speakers at that high of an SPL?
I would imagine i do every time there's cannon fire or a decent explosion (can you tell i mostly watch action films?). I've not sat there with a meter to see what it hits...but i've never experienced a quiet battle on the high seas in my theater room. And i would imagine its at those high levels where you'd expect to see the most problems in your bass response...so why do people not test it there when they're comparing the linearity of different subwoofers?

[thsmith]

I see all these charts online from people running frequency response measurements of their equipment. Almost all of them reside in the 75-85dB range as the average level they're trying to reach with each frequency.

My question is why this range? If someone (especially for subwoofers in a media room) is really interested in what their equipment can do at high SPL with lots of boom and bang and rumble, then why don't they test to see how even their responses are at the louder levels? 100dB or more?


I am only speculating but you need a reference point to measure and the end goal if eqing is to remove peaks.

Its you system you can do what you want but when most people post their graphs the intent is not to show SPL levels of their system but to represent their calibration efforts and the results.

[cschang]

I would imagine i do every time there's cannon fire or a decent explosion (can you tell i mostly watch action films?). I've not sat there with a meter to see what it hits...but i've never experienced a quiet battle on the high seas in my theater room. And i would imagine its at those high levels where you'd expect to see the most problems in your bass response...so why do people not test it there when they're comparing the linearity of different subwoofers?
Do you know at what levels you actually listen? 85dB to 95dB is pretty freaking loud to me.

I do see what you mean though. The FR graphs most people post are to show how even or uneven the response is in their room. What you are looking for are maximum levels.

Its you system you can do what you want but when most people post their graphs the intent is not to show SPL levels of their system but to represent their calibration efforts and the results.
That is stated better than what I posted.

[SAHSU]

I am only speculating but you need a reference point to measure and the end goal if eqing is to remove peaks.

Its you system you can do what you want but when most people post their graphs the intent is not to show SPL levels of their system but to represent their calibration efforts and the results.
So, would this mean that, short of a sub clipping, you should expect the peaks and valleys at 85dB to match the peaks and valleys at 105dB?

[SAHSU]

Let me phrase this question better. I'm not trying to get in an SPL war with other posters on other forums or anything like that (i'd lose anyway :)) but i AM curious if someone measures a full sine sweep from 15Hz to 30kHz, would he or she expect the same shape graph at 85dB as at 105dB or 45dB IF his equipment could handle the load? And, if not, why not...how would it differ, and why does the testing level seem to usually be around 75dB-85dB and not higher or lower.

[amdeutsch]

Part of this is what is reasonable to the human ear. The other issue is that the in-room FR, which you are measuring, won't noticably change the higher you go in volume. Human hearing is on a log scale. Introducing artificial peaks and valleys, equing. is up to who ever is doing it. You are setting your room up for a flat response. By going FLAT you are hopefully assuring that you are taking the room out of the equation and now get the effects that the movie, music artist wants to create. Hope that makes sense to you.