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LFE question

1046 Views 8 Replies 6 Participants Last post by  sportsound
My sub (Velodyne DD15) is set 4 db over the mains when using the AVR's internal test tones. Now, when I use DVE and check the LFE volume, I also keep the sub 4 db over the other speakers using the tones generated be the disc. ( I get higher spl reading from DVE but stay with the 4 db over reading I get from the AVR since the sub volume is calibrated with the DD software) In doing so, I need to lower the LFE volume to -7 db. I'm not lowering the volume in the channel set up menu, only the LFE signal generated by a DD signal. Is this the correct way to set the LFE level?
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No. The LFE level should be left at zero. You want to adjust the subwoofer channel volume. And the subwoofer tones on DVE are incorrect, BTW, so you should continue to use your AVR for channel balancing.
So, another words, even though the Dolby Digital LFE level when set at 0 reads around 15 db louder than the other channels, I should ignore this because the test patterns are incorrect and the LFE wont be louder than needed as long as the channel level in the AVR and DD15 are set correctly?
Why do some receivers have separate LFE level and sub level adjustment? My older h/k only has sub level adjustment.
THat is a good question Jake. I don't have a real answer, only speculation. I could think of a few times when it would be handy, but don't know if those are the reasons why the LFE level control exists. My Denon has both. The manual says to put the LFE to its max at +15. It has 5db interval. So -15, -10, -5, 0, 5, 10, 15. I guess it just boosts the signal to the sub. The sub level adustment is used to fine tune it to a proper level 1/2db at a time. Again, there is probably a real answer, I just don't know it.
Originally Posted by rynberg
No. The LFE level should be left at zero.
Further down, Bsheldon says:

...the manual says to put the LFE to its max at +15. It has 5db interval. So -15, -10, -5, 0, 5, 10, 15. I guess it just boosts the signal to the sub...

Are we talking about the same things??

Cheers / Avliner.
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Strange, I don't why Denon would do that (my older Denon AVR doesn't). Typically, there is a setting for 0 LFE or -10 LFE (or a range from 0 to -10). When the LFE is set at 0, the signal from the LFE is the same level as the signal from all of the main channel speakers set to SMALL. However, the LFE signal is boosted 10 dB in DD/DTS, so most manufacturers give you the option to reduce LFE by 10 dB.

Personally, I don't see any reason for this feature except for the situation of running NO subwoofer. Then the LFE signal going to the main L+R could be reduced (which is what I did several years ago before I had a sub).

The point is that the LFE should be set to 0 or max or whatever the individual AVR calls it.
Yeah, really stange. I do own a Denon also (3805) and haven't found anything on manual saying you must put the LFE to its maximum ( + 15db), EXCEPT at the INPUT SET UP GRID, where they mention that the EXTERNAL IN ( for SACD/DVD-A) settings on the SW levels were set upon shipment from the factory ( +15db).

Anyway, it's interesting to know about that. As far as I understand, whenenver you select your speakers as SMALL, you don't have the option to adjust the LFE level anymore, right?

My doubt lies on whether I should leave the LFE + MAIN settings at ZERO or + 15db?? (and then are re-set the speakers to to SMALL).

Cheers / Avliner.
The answer becomes clear when you understand what the LFE channel is used for. If you are a content PROVIDER (audio production mixers, etc) the LFE channel (the .1) is used for extra bass information. When the mixer wants a little more emphasis for an explosion or a music cue he'll direct some of that signal to the LFE channel as well as the fronts and maybe the surrounds.

The home bass management system takes that information PLUS any low frequency information below the crossover frequency and sends it to the subs. Some people balance their system for music and feel the movie effects are too loud. The LFE trim controls the amount of LFE channel information sent to the sub without affecting the balance of the sub to the mains. This way you can have a system that is balanced for music and movies. (in theory).

I hope this helps.
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