Subwoofer Level + Sound and Vision

[Dark-007]

I'm getting confused. I want to run my subwoofer flat. The same level as my surround speakers.

I've read that the Radio Shack Analog meter is inaccurate at levels under 80hz, and that the Sound and Vision sub tone is at 40hz, which means a variance of -2.5db.

So, I set my sub level to 83db, while the rest are at 85db.

But then, I come across this forum, and you are stating that the sub should be set 2-3db HIGHER than the satellites?

Anyone know for sure? Any good reference sites I can check out?

Thanks.

[poneal]

Some people set the subwoofer between +3db to +6db higer than the mains (not surrounds) for added impact of bass. I have mine set 3db higer because of the -2.5db dropoff of the radio shack meter. When using the Sound and Vison Test DVD a tone alternates between the sub and I belive the left main speaker. Just set the sub to +3db higher than the left speaker. If it sub sounds to loud just lower the volume a tad until your satisified. Also, you should set the sub level higher not lower than your mains.

[Woochifer]

Actually you got that variance in reverse. The microphone used in the RS analog SPL meter is LESS sensitive in those low frequencies, which is why if you're using a reference level of 85 db on the mains, then the level on the sub should be at least 87.5 db.

On this board, the commonly referred to recomendation that you set the level on the sub at least 4 db higher is based on the fact that human hearing is less sensitive in the low frequencies as well. There's also personal preference -- a lot of people just like more bass.

[Dark-007]

Actually you got that variance in reverse. The microphone used in the RS analog SPL meter is LESS sensitive in those low frequencies, which is why if you're using a reference level of 85 db on the mains, then the level on the sub should be at least 87.5 db.

On this board, the commonly referred to recomendation that you set the level on the sub at least 4 db higher is based on the fact that human hearing is less sensitive in the low frequencies as well. There's also personal preference -- a lot of people just like more bass.

Excellent. Now, I have one more question, hopefully this can be answered by tomorrow morning, when I have enough alone time to set the sub level again.

When I read the needle during the test tone, it varies about 2db, meaning it sways back and forth, but never higher or lower than a 2db difference. For example, when I take a reading as it's set up now, the needle moves back and forth between 82db and 84db.

I figured I'd take the average of the two readings(83), and call that the correct setting(-2), but should I be setting the level to the highest point the needle reaches, or the lowest point?

Thanks again, you guys are great.

[Woochifer]

Excellent. Now, I have one more question, hopefully this can be answered by tomorrow morning, when I have enough alone time to set the sub level again.

When I read the needle during the test tone, it varies about 2db, meaning it sways back and forth, but never higher or lower than a 2db difference. For example, when I take a reading as it's set up now, the needle moves back and forth between 82db and 84db.

I figured I'd take the average of the two readings(83), and call that the correct setting(-2), but should I be setting the level to the highest point the needle reaches, or the lowest point?

Thanks again, you guys are great.

Sound waves don't behave in a neat linear manner, especially bass frequencies with their long wavelengths. Try filling a large pan with water, and then put a bunch of other objects into the pan so that they poke out above the waterline. Hit the water with your finger and watch how the waves bounce off the objects, and how they interact with one another when they intersect. Soundwaves behave the same way (except that the wavelengths are far more variable) in that the waves intersect and interact with one another throughout a room.

With your SPL measurement, you should be looking for the "average" level. Basically, the midpoint between the extremes. Another way to keep the reading more stable is to mount the SPL meter on a camera tripod. Soundwaves can bounce off of your body while you're taking the readings, plus with your hand, you won't necessarily hold it at a consistent height and angle.

[Sir Terrence the Terrible]

Excellent. Now, I have one more question, hopefully this can be answered by tomorrow morning, when I have enough alone time to set the sub level again.

When I read the needle during the test tone, it varies about 2db, meaning it sways back and forth, but never higher or lower than a 2db difference. For example, when I take a reading as it's set up now, the needle moves back and forth between 82db and 84db.

I figured I'd take the average of the two readings(83), and call that the correct setting(-2), but should I be setting the level to the highest point the needle reaches, or the lowest point?

Thanks again, you guys are great.

It is perfectly normal for the needle to sway a bit. It is probably picking up a room mode. Since you are only dealing with a 2db swing, go for the higher number. If that is too high upon playback, adjust it down a notch.

[Dark-007]

Got it.

I have a camera tripod I can use, and the sub is floated on an Aurelex Gramma pad, since I live above my garage.

I'll try setting the sub so the average level is 87-88.

Thanks guys.