I have a simple LFE question guys [Archive] - Audio & Video Forums

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ChrisY
05-02-2006, 12:47 PM
Is it a good idea the add extra volume to your sub from your receiver when using the LFE which already seems to be pretty powerful with the volume level set at 0 on the receiver or is it a matter of personal taste. I also read somewhere that your subwoofer volume level should be set higher for watching movies.Is this true and how much higher and how do you set your own Subs with your receivers.Thanx

paul_pci
05-02-2006, 01:47 PM
I control the volume through the sub itself and leave the receiver setting where it's at. What volume is best is roughly a matter of taste that you may wish to experiment with as to whether you do like it higher for movies or not, and this will also be affected by at which frequency your sub begins to drop off.

Woochifer
05-02-2006, 04:33 PM
Generally speaking, the consensus on this board seems to recommend setting the subwoofer level to +4 to +6 db above the mains. But, keep in mind that the +4 db recommendation compares the actual sound levels that your main speakers and subwoofer put out using a test tone. It has nothing to do with whether the level on your receiver says 0 db or whatever.

The first thing you have to do is calibrate your subwoofer such that the level control on the subwoofer itself is set to a position where the SPL (sound pressure level) matches the output from the main speakers.

To do this, you should use a SPL meter to accurately measure the output. Your receiver should have a test tone generator built in. Use that and set your mains to a level of 75 db to 85 db (as read on the SPL meter, not your receiver's volume indicator), and then calibrate the subwoofer by setting it to a level that matches the mains. Many receivers don't allow you to go higher than 0 db on the subwoofer level, so you might want to match the subwoofer output using a value of -10 db on your receiver, so that you'll have some flexibility with increasing the output level to match your preferences.

Once you have the baseline levels for the sub and the mains matched, THEN you go back to the settings on your receiver and boost the levels by 4 db to 6 db.

emack27
05-02-2006, 04:55 PM
To do this, you should use a SPL meter to accurately measure the output. Your receiver should have a test tone generator built in. Use that and set your mains to a level of 75 db to 85 db (as read on the SPL meter, not your receiver's volume indicator), and then calibrate the subwoofer by setting it to a level that matches the mains. Many receivers don't allow you to go higher than 0 db on the subwoofer level, so you might want to match the subwoofer output using a value of -10 db on your receiver, so that you'll have some flexibility with increasing the output level to match your preferences.

Once you have the baseline levels for the sub and the mains matched, THEN you go back to the settings on your receiver and boost the levels by 4 db to 6 db.

There's a quicker, cheaper and easier way to do this. However it might not be as accurate. Well doing what was mentioned above is not all that accurate either unless you're in a sound chamber or something. But anyways here's another way: Tune your tuner to a station where you got white noise (only static) and switch back and forth between sub and mains. Noticing differences in volume/loudness is easier this way than with music. Your subs vs. mains should be set at equal volumes.

ChrisY
05-02-2006, 05:22 PM
Thanx a bunch guys, all of your input was and is greatly appreciated.

Woochifer
05-02-2006, 05:57 PM
There's a quicker, cheaper and easier way to do this. However it might not be as accurate. Well doing what was mentioned above is not all that accurate either unless you're in a sound chamber or something. But anyways here's another way: Tune your tuner to a station where you got white noise (only static) and switch back and forth between sub and mains. Noticing differences in volume/loudness is easier this way than with music. Your subs vs. mains should be set at equal volumes.

Pretty much any multichannel receiver dating back to the Pro Logic era will have a test tone generator built in, so no need to play static (and test tone levels are much more stable than radio static). An even more accurate method would entail using a test disc, because those use narrow band test tones that are different for the mains and subwoofer. I don't see how an in-room measurement would not be accurate, because that's the actual SPL as measured from the listening position.

Setting a sub using a SPL meter is way more accurate (and actually faster) than trying to set it by ear, especially if you're trying to equalize the sub and main output level. For one thing, the human ear is less sensitive in the lower frequencies than in the midrange, and the mains and sub work in entirely different frequency ranges. This difference in hearing sensitivity is one reason why many posters on this and other boards recommend calibrating a subwoofer to at least +4 db.

emack27
05-02-2006, 06:46 PM
Setting a sub using a SPL meter is way more accurate (and actually faster) than trying to set it by ear, especially if you're trying to equalize the sub and main output level.

Yeah, I guess you are right, but whose going to go out and buy an SPL meter anyway?
You can download a tone generator online for a free trial period if you really want to get serious.

musicman1999
05-02-2006, 07:01 PM
I got one.

bill

kexodusc
05-03-2006, 04:13 AM
I believe anyone who owns a home theater and is more than an occassional user of it owes it to themselves to buy an SPL meter. It's just too useful an instrument.

I often recommend adding a few extra dB's of gain at the receiver and taking off a few dB's of gain at the sub amp to get desired total sub volume - not because it sounds better or anything, but an aweful lot of auto-on features in sub plate amps don't notice the voltage if the LFE signal from the receiver is too low, and won't power on all the time, especially at lower volumes. Doesn't hurt. Other than that, whatever comination of the two you use is up to you.

Sir Terrence the Terrible
05-03-2006, 05:53 AM
Yeah, I guess you are right, but whose going to go out and buy an SPL meter anyway?
You can download a tone generator online for a free trial period if you really want to get serious.

Why download a tone generator when you already have a pink noise generator in your reciever designed to do that job already? Use that (and a SPL meter) and you are already getting serious.

shokhead
05-03-2006, 05:54 AM
Thats what my SVS did,had the gain to high and the auto/on didnt work unril the master volume on the receiver was way up. I keep it around 11 o'clock and dont touch it from the sub. BTW,mine is more like 6-8db higher,i like my bass.

Woochifer
05-03-2006, 07:36 AM
Yeah, I guess you are right, but whose going to go out and buy an SPL meter anyway?
You can download a tone generator online for a free trial period if you really want to get serious.

Check around the board, you'll find that a lot, if not the majority, of the regulars (myself included) use and highly recommend SPL meters. If you have a subwoofer and a multichannel system, it's way too valuable a tool to go without one. Two-channel systems are easy to set and tweak by ear, but with five speakers and a subwoofer, forget about trying to accurately match the levels by ear.

Aside from level matching all the speakers in your system, you can use it for identifying room effects, anomalies in the frequency response, optimal subwoofer placement, and proper equalization levels. Not bad for a $40 device that's readily available at Radio Shack.