so whats the story with LFE?

[BEETLEMAN]

i finally got my subs hooked up last night. and plugged in a new movie but im not getting what i thought i would get from the lfe source on my h/k. each of my subs is an 8" that i have tuned the cabinets to about 40hz, with about 200 watts going into each one. with the sub adjustment turned up on my h/k to about 6 i still only get just a slight rumble not the bone crusher i was expecting. any thoughts?

[kexodusc]

Well, 8" subs aren't exactly huge, and tuning the cabinets to 40 Hz displays a real limitation in bottom end response. I'm guessing 32-35Hz.
Generally it's advised you set your sub levels at + 3 to + 6 dB above your main speakers.
Sub placement is also very critical. Make sure your subs aren in phase, both with each other, and your system. It's easy to get a lot of cancellation, room modes and nodes are a pain in the but to work around too.

Could be a receiver setting...verify you have your speakers set to "small" and your LFE or bass setting to "sub" only. Set the cutoff/crossover to 80 Hz or so.

[BEETLEMAN]

yeah i have a h/k avr-135 and the speakers are set to large, the sub is set to lfe but i dont have an adjustment for my sub crossover frequencies. the one thing i havent tried is i can add right and left to the lfe as a combo. the sub is allready at plus 6. mind you i do have four subs hooked up one in each corner of my room. im using logic 7 enhansed on the reciever settings.

[MCH]

Well, first of is the calibration aspect. Then it's the subwoofers themselves and their power amplification. 8" subs aren't really considered subwoofers; they are more like woofers. Personally I wouldn't go smaller than 15" if you really want slam for HT. Then you also consider your source material; like what's on the DVD. There are some good test DVDs or even CDs (for musical reproduction of bass). Fight Club at the end scene is a very good example to try to test your subwoofer. If your room isn't shaking with this DVD go back to the beginning and see what part applies to your dilemma.
good luck
I have a 15" Tempest in an Octagonal Cabinet that is pure magic.

http://gallery.audioreview.com/showp...cat=506&page=2

[BEETLEMAN]

Well i hooked up my cd player to my system and put in some nickleback and let me tell you this thing really rocks. the bass is spot on and it will grab you and toss you around the room. so i think i have answered my own question. i have a nuance 10" sub 250 watts that i will use for movies and i will use my other subs for music. so thanx for the input guys.

[Geoffcin]

i finally got my subs hooked up last night. and plugged in a new movie but im not getting what i thought i would get from the lfe source on my h/k. each of my subs is an 8" that i have tuned the cabinets to about 40hz, with about 200 watts going into each one. with the sub adjustment turned up on my h/k to about 6 i still only get just a slight rumble not the bone crusher i was expecting. any thoughts?

If your using a splitter then each sub will only see half the signal strength. You should be able to compensate using the receivers adjustments.

LFE is very specific to the movie. Some don't have any LFE at all! Others like Star Wars, or Jurassic Park, can give your sub a real workout.

[kexodusc]

If your using a splitter then each sub will only see half the signal strength. You should be able to compensate using the receivers adjustments.

LFE is very specific to the movie. Some don't have any LFE at all! Others like Star Wars, or Jurassic Park, can give your sub a real workout.

Not exactly, voltage remains constant througout a parallel circuit, so when you use a splitter, there is no loss in signal strength to each sub. Most of those tiny signal amps have more than enough miliamperes to split an LFE cable several times before the resistive load is too much. Cool experiment to perform if you've got a multimeter and way too much free time on your hands.

I'm guessing there's a difference in output voltage between DVD and CD player in this case...a very common, and annoying occurance

[Geoffcin]

Not exactly, voltage remains constant througout a parallel circuit, so when you use a splitter, there is no loss in signal strength to each sub. Most of those tiny signal amps have more than enough miliamperes to split an LFE cable several times before the resistive load is too much. Cool experiment to perform if you've got a multimeter and way too much free time on your hands.

I'm guessing there's a difference in output voltage between DVD and CD player in this case...a very common, and annoying occurance

When I run a splitter in my velodynes? I just don't seem to get that effect from doing it.

[kexodusc]

When I run a splitter in my velodynes? I just don't seem to get that effect from doing it.

Not necessarily - depending on the subwoofer manufacturer, different things can happen. Today, the most common thing I'm seeing (my last 4 subs and most people I've asked) is that the plate amp will sum the 2 separate L/R inputs before going to the power amp. You will actually get up to 6dB of voltage gain depending on how the summing is done..

Theoretically, you could get as much as a +3 dB output increase at the woofer for a given setting.

My last few subs manuals actually recommended using the L/R with a splitter increase the input strength. The plate amp just sums the inputs into a mono signal for the woofer. In a perfect system it'd be double, but you probably lose some. It's pretty noticeable and easy to measure.

I'm not sure what the real advantages are though. I accomplished just as much for years using 1 cable. The only benefit I can think of using the Y-cable is if your receiver's LFE output signal is weak while at or near it's max limit...not likely these days.

I've heard a lot of people (usually with cables to sell) say it benefits signal purity by reducing loss. I can't see how.

[BRANDONH]

yeah i have a h/k avr-135 and the speakers are set to large, the sub is set to lfe but i dont have an adjustment for my sub crossover frequencies. the one thing i havent tried is i can add right and left to the lfe as a combo. the sub is allready at plus 6. mind you i do have four subs hooked up one in each corner of my room. im using logic 7 enhansed on the reciever settings.

Try setting the speakers to Small then more bass will go to the LFE.

[BEETLEMAN]

Try setting the speakers to Small then more bass will go to the LFE.

i just finished watching star wars ep 3 and i did what you fellers suggested by putting the speakers to small and i turned the sub up to +4. the results were amazing to say the least.
these subs perform exactly as they should. i built them to give me a more dynamic bottom end instead of just a one note bass that most subs are famous for.
im suprised to say they do give you the boom when needed, but they also give you the upper bass part of the soundtrack as well. which has been missing with my other subs. its hard to discribe but it fills the void that i have seen with my other subs.
also the feeling of being able to build your own stuff gives one a bit of pride as well, i just wasnt expecting it to sound as good as it does. clear well defined bass that can hit when it has to and also beable to be subtle at lower volumes is what i was looking for.

[Woochifer]

Before you do ANYTHING, you have to calibrate the subwoofer levels using a test disc and SPL meter. Typically, you would want to adjust your actual subwoofer output level (the indicator level on your receiver is completely arbitrary because an additional adjustment on the back of the subwoofer unit needs to be accounted for) so that's its SPL reading is at least 4 db higher than the mains (this is due to decreased human hearing sensitivity in the lower frequencies).

Once you have the levels properly calibrated, then you need to go about making sure that your receiver is directing the LFE channel through the subwoofer output and not into the main speakers.

And with the terminology, the LFE simply refers to the low frequency effect channel on a 5.1 or 6.1 soundtrack (the ".1" track if you will). It's NOT synonymous with the subwoofer output. Any other bass that gets directed into the subwoofer output using your receiver's bass management settings is not a part of the LFE track.