LFE is too quiet in Avia! (1 Viewer)

[Jeff_Brom]

i'm using the Avia disc to set/test my levels... I have an Onkyo 797, 6 NHT superzero's and an NHT Subone... i'm using the test that pans around to all 5 channels plus the LFE and plays the low freq tones... It is noticeably quieter (to my ears and the spl meter) when it hits the LFE channel... In the Onkyo setup, however, the sub channel reads the same SPL (~75db) as the other channels... the LFE setup for Dolby Digital and DTS is at 0db so its not losing volume there... all speakers are set to small, so the tone plays from the sub for all channels...

any ideas? it doesn't make any sense to me, because its the same tone coming from the same sub, so it should be the same volume unless bass management is messed up, right?

 

[Steve_Ma]

I'm not sure if this is part of the issue, but take a look at this thread. Go to "Jack G"'s comment about the Avia disk volume near the bottom.
http://www.avsforum.com/avs-vb/showt...SPL+and+volume
--S

 

[Jeff_Brom]

i also found another post written by Guy Kuo the avia creator... He indicated that there was a 10db compensation built into the avia LFE level to cancel out something added/substracted in the processing...

if it was a difference in spl between the sub and the other speakers, that would be one thing, but in this case its the sub vs. the sub... the only difference is whether its redirected bass from small speakers to the sub, or pure sub bass from the LFE channel...

in the avia menu it says that if you experience what i'm experiencing, then you have problems with bass management... but i don't know how to fix it!

thanks

Jeff

 

[brentl]

In mot cases people run the sub about 10db ouder than the rest of the speakers. So add 10dbs and you should be happy.

Brent

 

[Scott Page]

Do not, I repeat do not run your sub at +10 db's. DD and DTS soundtrackes already add 10 db's to the LFE soundtrack. If you also add 10 then your bass will be 20 db's louder than the rest of the soundtrack during high bass passages. Can you say "blown subwoofer"?

Use either AVIA or your internal tones. Know that your Radio Shack meter will read about 3 db's less on the sub tones due to meter problems.

In other words if the meter reads 72 (82 AVIA)on sub tones and 75 (85 AVIA) on the other channels then it is balanced. Many do like it a little bit hotter and may adjust the sub to also 75 (or 85 if using AVIA), which translates into reference plus 3 db's on the sub.

Is that clear?

As to whether AVIA sounds right or the internal tones, try it both ways and pick which you prefer. For my Denon 3801 I use the internal tones at 75 db's. The AVIA tones (set to 85 as it should be) are 8 db's louder than the Denon on my setup. I have no idea why but prefer the more realistic Denon level.

 

[Jeff_Brom]

everybody keeps telling me to turn the sub up... but ALL of the tones are coming from the sub.. .its just that the ones that are coded from the LFE channel are quieter than those from the other 5 channels... its the same low freq pink noise so the inaccuracies in the spl meter shouldn't matter... if i turn the sub up, they ALL get louder... the only volume control i have that is LFE specific is already maxed out...

i tried some other options... i told the Onkyo that i didn't have a sub at all and then it forces front r/l speakers to be "large" .. i then ran the front r/l pre outs to the sub and now the level is consistent for all channels including LFE...

so what does this mean? was there some problem with the way the Onkyo was creating the signal for the sub out? (before the sub was connected to the sub out, and the onkyo was set to sub yes and all speakers small)...

thanks,

Jeff

 

[Lee Bailey]

Jeff, do NOT adjust the LFE control on your receiver when setting up your sub with Avia! Put it back to where the manufacturer set it. You should only adjust the SUBWOOFER output setting on your receiver to get the tones to the right level. The LFE information is able to go up to 10db higher than that when playing a movie. It is also possible that you cannot HEAR the lower frequency tones, though your meter shows you that it is measuring something. Trust the meter. Adjusting 4 to 6db higher than your mains is a pretty normal practice though, and it may get you effects to sound the way you want.

 

[Jeff_Brom]

i have left the LFE alone... it comes set at 0db... i was just pointing out that i can't go any higher, all the onkyo will let you do is lower it from 0 down to -infinity...

looking at the meter, it drops about 7-9 db when playing through the LFE versus the other channels... that was with the old hookup... with the new arrangement (see above) the level stays consistent for all channels...

something still seems fishy to me about all of this...

thanks for the responses guys...

 

[Jeffrey Forner]

Jeff;

Try this: Run the amp on the sub hot. In other words, increase the amp level on it to about 3/4 full power. Then adjust the Subwoofer setting on your receiver until it matches your speakers.

Hope that helps.

 

[Jim_C]

Read this article by Guy. It explains how to use Avia WRT LFE.
http://www.hometheaterforum.com/htfo...=avia+bass+LFE
There are numerous threads that discuss receiver LFE and subwoofer level settings. A common piece of advice is to set the subwoofer level in the -5 to -8 range and control volume at the sub. Why? To minimize distortion.
I'll search for more threads to back this up. However, I've read this numerous times from people here that really know this subject.
I wish that Vince M. would wander by and post.
EDIT Check out the online manual for the SVS 20-39PC pages 6 and 7. It refers to what I mentioned WRT a negative setting for the subwoofer level and minimizing distortion at the input level.
http://www.svsubwoofers.com/svpoweredsubs.htm#20-39PC

 

[Lee Bailey]

Jeff, perhaps we need someone else who is familiar with your particular sub to give some advice. I went to their website, but could not find an online users guide. It looks like it has an external controller unit that you actually hook your system to. It that where you can hook your speaker level connections too?

 

[brentl]

My basic point was; it's much more important to set the mains up properly, the sub is set up to taste.

Brent

 

[Vince Maskeeper]

I have wandered by to post
As Jim C and "the man" J.Fo offered- I too personally suggest running the sub volume wide open, or as open as you can get - while controlling the sub with preamp controls.
Although, I don't think that particular point has anything to do with this particular thread, it's good advice none the less.
One question- you mentioned using a LFE tone on AVIA. Where is the dedicated LFE signal on Avia? I know the subwoofer test signal on the main channel level setup is in the left front channel, and is rerouted via bass mgmnt. This is not a dedciated LFE signal. Could someone point me to the deicated LFE signal? I haven't really explored the audio tests on this disc- I like VE and Dolby's discs better.
Really, what you're saying is that with LFE pads in proper position (all the way up)- you calibrate using internal test tones. Everything is hunky dorey. When you check this calibration level against AVIA's tones, the subwoofer channel (as provided by Avia) is 10db low.
The problem is: you did not say which specific tone from AVIA you are using when experiencing this 10db reduction.
• Are you using the main speaker setup tones (in these, the bass is rerouted from the main channel to supply a sub tone)
or
• Are you using some dedicated LFE tone found elsewhere on the avia disc?
I would have 2 theories on this issue:
THEORY ONE (less likely)
[if you are actually using the main speaker setup tones, and haven't found some dedicated LFE tone on the disc]
1) If you are using the main speaker level setup for AVIA, you aren't getting dedicated LFE signal, you're getting bass rerouted from the mains.
2) If your receiver test tones is generated as "LFE" and properly compensated.
3) Then there is a 10db difference from rerouted bass (avia test signal) to LFE signal (receiver test signal).
If this is the case:
Either yours would be the first receiver I have ever heard of that the PROPER LFE pad position would be -10, or the bass mgmnt rerouting is reducing the rerouted signal. If in fact #1 and #2 are true, then if you adjust the LFE pad down by 10, the rerouted bass and LFE would be the same (although you wouldn't know whos fault it was: lfe or reroted- it would be fixed). Problem solved.
If you're sure you are using DEDICATED test signal that is encoded at the proper level, then it probably isn't theory one.
THEORY TWO (more likely)
[if you HAVE found some dedicated LFE tone on the disc that is at a given level that can be used to calibrate]
1) If you are using the a dedicated LFE setup for AVIA, you are getting pure LFE signal, you're NOT getting bass rerouted from the mains.
2) Your receiver's test tones are generated as LFE bat are NOT compensated for the 10 difference in level to the main channels.
3) This would cause the AVIA tones (which are, assumed for this example, correct) to measure 10db lower than your reciver tones. In other words, your receiver's LFE processing is boosting it's own tone by 10db- and it's own tone was not dropped 10db to compensate.
4) You could test this theory in a number of ways:
a) If You have found a dedicated LFE signal on AVIA- calibrate to it. Now return to the main speaker setup, where the tone is mearly rerouted signal from the mains... is it still correct? If it is, then both Rerouted bass and LFE bass are coming up to proper level at that setting, and then your receiver's LFE tone is 10db higher, I would assume the tone in the receiver is incorrect.
b) Run your test tone on the receiver- and measure it. Now, adjust the LFE pad setting (not the subwoofer setting), and see if this has an impact on the internal tone. If it does, I'd bet a dollar that the internal tone is being generated at the same level as the main tones, and the LFE pad is then boosting it (if the LFE pad is able to boost it, the tone should have started 10db low, like LFE signal on DVD!).
After you test the terory and calibrate, you can verify this after you finish with a few films, and make sure the bass doesn't seem insanely low.
THEORY THREE (most likely??)
[if you HAVE found some dedicated LFE tone on the disc that you are using to calibrate]
1) If you are using the a dedicated LFE setup for AVIA, you are getting pure LFE signal, you're NOT getting bass rerouted from the mains.
2) It is possible that the given LFE tone is not encoded at the same level as the main speaker tones. I am not familiar with this dedicated LFE tone, and would wonder what level it was creted at. Is it possible that because this tone is some OTHER kind of test that it is not encoded at -20dbfs as the main tones are? I would say it's very possible you are using a tone that is not really at the same level.
3) You could test this theory as well. Calibrate with your receiver tones. Leave LFE pad all the way up. Play AVIA's main speaker level tones (the ones where sub comes from rerouted main channel signal)- is the rerouted bass tone correct in level vs. the main channel tones?
• If they are the same level, then I would say the Avia dedicated LFE tone is not at the proper level, and I would ignore it.
• If they are not at the same level (if the rerouted bass tones are 10db low as well)- then see Theroy #2- I'd guess the LFE tones in your receiver are wrong.

if it was a difference in spl between the sub and the other speakers, that would be one thing, but in this case its the sub vs. the sub... the only difference is whether its redirected bass from small speakers to the sub, or pure sub bass from the LFE channel...

Not necessarily- remember you might not be comparing sub to the sub. The receivers tones might be wrong, and you might be using redirected bass from main channels- in which case you're comparing 2 different things. Granted, the two should be the same level- but they are indeed two different things. In your case, it's possible that the reroted bass by the bass management on yur reciver is reduced by the processor for some reason.
The key here is to determine exactly which tones you're using, and what is happening with each.
I would love to investigate the levels of the dedicated LFE tone on avia:, I have avia and VE as well as a dolby test disc, 5 versions of THX optimode, and 2 receiver's internal tones- I would be happy to check them against one another- but I don't know where the Avia dedicated LFE tone is located.
Hope that all made sense. If you're seriously lost, email me your number and I'll give you a call and we'll get it figured out.
-Vince

 

[Ryan Schnacke]

My Onkyo 595 has a very similar behavior. And I believe Vince's 2nd explanation is correct except that the Avia tones are rerouted bass signals from other channels, not LFE. But that doesn't matter. Basically it means that the Onkyo's test tones are WRONG! Don't even bother with them.

When I first calibrated the receiver, using the internal tones, I figured I must be an extreme basshead because the movies and music (all speakers set to small) didn't sound good until I pushed the sub to +12dB or so (uncorrected!) over the mains. Once I calibrated with Avia and THX Optimode I realized that I really only had it about +2dB (uncorrected) over the mains.

For those using THX Optimode I found that the surround signals are about 2dB too low. If you don't correct for this, then you will calibrate the surround levels about 2dB too high. I did this at first and did notice that the surrounds were just a bit loud. The rest of the Optimode signals agree with Avia to within about 1/2dB and are recorded such that 85dB = reference just like Avia.

 

[Jeremy Anderson]

Avia does NOT have a dedicated tone for the LFE. The bass adjustments on the Avia disc are for overall bass levels when using a system with all speakers set to small. Once you have adjusted the overall bass level with all speakers set to small, the subwoofer should be at the proper level for LFE as well (assuming you haven't tinkered with the LFE padding control). If your receiver has LFE pad controls, the defaults should be 0db for DD and +10db for DTS. If your receiver shows this only as a range from -10db to 0db, set DD to -10db and DTS to 0db and this should make up for the difference. You'll really just have to experiment to find out. Chances are that the +10db pad for DTS may already be accounted for and both should be at 0db... but who knows.
On Jeff's original question: The 6 channel pan on the Avia disc is NOT for calibration purposes, and is not an indicator of a deficiency in the LFE channel.
As for the internal test tones on the new Onkyo lines, my experience with the 595 and 696 is that the test tone for the subwoofer is 10db too low and all the test signals are 5db off from reference. If you're using the internal test tones for calibration, set the speakers to 80db and the sub tone to 90db, and this should match up with an Avia/VE calibration at 85db/75db respectively (since those two discs are encoded at different levels).
That either helped you... or confused you further.

 

[Jack Gilvey]

If LFE must be independently calibrated, use the Low Freq 6 Channel Sweep in AVIA (Title 6 chapter 29). This test has a discrete LFE channel signal to verify that LFE level is correct relative to the other 5 channels of bass content. All should read the same SPL.

 

[Jeremy Anderson]

But wait... he also says:

The only compensation is for the discrete LFE in the 6 channel pan. That is 10 dB down electrically.

Is this to take into account the +10db padding of the LFE channel that is done by the receiver?

 

[Jeremy Anderson]

Nevermind, he also says:

(For the overly knowledgeable ... the LFE signal is already pre-compensated -10 dB in intensity so it yields the same SPL as the other channels if LFE gain is at 0 dB. No need to worry about the 10 dB playback boost, it's been accounted for)

And there you have it...

 

[Jack Gilvey]

Right. LFE is encoded by spec at -10db for headroom purposes, but is boosted back to level as a default by the processor. When playback is set at the default "0 db" setting (not -10db, as some allow), LFE from that sweep should playback at the same level as the rest.
I think.

 

[JohnnyG]

Right, which puts me in the same boat as Jeff! That 6-channel pan on Avia also registers about -10db from the rest on my system! My receiver is an H/K AVR310 and it doesn't have any control for the LFE setting (just SUB).

This is real head-scratching stuff!