Bass Management and LFE: NOT the same thing!

1. You should always always always run all available positions.  The algorithm needs to collect as much information from the room as possible.  The mic placement should follow the guidelines shown here.

2. There is no need to re-run the calibration if you change the level.  Audyssey is setting it to film reference.  If you have a personal preference for a different sub level then you can change it after the calibration is finished.  All AVR settings prior to running the calibration are ignored.  

Thanks, Chris. I figured as much. That's why I wrote to you. Perhaps an answer to another question might help me choose the best way to blend my passive subwoofer with my L and R speakers.  Does 2EQ adjust at specific bass frequencies? If so, what are they? 

Hi Barnet,

When connecting the speakers to the sub, the AVR doesn't know there is a sub in the system and so it can not perform bass management.  This can be a drawback because the analog filters in the sub that are now in charge of blending with the main speakers are usually not of sufficiently high order to perform a proper overlap.

In any case, my preference is always for the deepest possible bass extension.

Hi Chris,

I have Audyssey 2EQ in my Onkyo receiver. I've been using left and right speakers that are flat to 58 Hz. anechoically and allegedly reach -3 db. at about 42 Hz. in domestic environments like mine. (I don't have a powered subwoofer.)

I recently acquired an (unpowered)  B&W Acoustitune subwoofer, which is designed to be driven by the same amplifier(s) as the speakers whose bass it extends. I'm thus connecting my left and right speaker outputs to the Acoustitune's input terminals, and connecting the left and right speakers to the Acoustitune's output terminals.

The Acoustitune comes with four ports that differ in length. The shorter ports render the subwoofer more efficient but "roll off" more steeply in the deep bass (relative to, say their output between 80 and 100 Hz.). The longer ports yield flatter overall frequency response. (All ports yield have similar absolute deep bass output; they differ most strongly around 80 Hz. with reduced differences in output at lower frequencies.) 

If I were not using the Audyssey EQ, I would have to decide whether the additional output below between, say 20 and 58 Hz. that a shorter port can provide justifies  the additional "overlap" (and emphasis) in the higher frequencies. 

How do you suggest I choose the port, given that I'll be using Audyssey 2EQ?

yes the Wharfedale Diamond SW150 subwoofer  i have has a a knob which you can select crossover from 35hz to 85hz, so does  this mean i can set the LFE on my onkyo to 90hz instead of 120hz?  which will help the sub crossover do less work?  thanks chris

Do you mean that the upper frequency of the sub is 85 Hz?  Seems unusual... But, yes, if that is the case then you would be missing anything in the LFE track that is between 85 Hz and 120 Hz.

hi chris,   so if i have a subwoofer that can only go to 85hz and i set my onkyo 607 LFE to 120hz,  am i missing some of the sound track in a 5.1 movies?  is it better  to buy a sub that goes to 120hz or am not missing much?

Hi Chris,

Thanks very much for your help.

Excellent product!

Hi Andy,

If you have a preference for higher-than-reference bass levels then it's best to do that in the AVR.  That way you can always go back to the original level.  2EQ will not be affected by changes in the sub level.

Hi Chris,

Thanks for this, very enlightening!  I have noticed that the sub is better when left with the gain near 12 o'clock and it is within the range you stated. 

But as far as my second point, if bass is a little quiet, would you recommend adjusting the AVR dB setting for the sub or adjusting the gain on the sub?

Also, by adjusting the sub am I right in thinking this does not affect Audyssey 2EQ.

Cheers

Andy

Hi Andy,

There is no need to worry about getting the speakers to have 0 dB level adjustment.  The whole point of calibrating is to let Audyssey measure and automatically set the levels.  As long as the sub level is not out of the range that the AVR can handle (–12 dB for most AVRs) then you are fine.  This "need" to get the sub close to 0 dB is one of those silly internet myths that have no basis (imagine that!).  

Hi Chris,

I have an Onkyo 609 and have been very impressed with Audyssey 2EQ.

I calibrated my speakers by running Audyssey Quick Start continously adjusting the gain on my sub (Paradigm) until I got a channel to 0dB (+/-3dB) so the centre is now -3db.  This put the sub gain at about 9 o'clock and a reading of -3dB.  I then ran a Full Audyssey setup and saved it.

Crossovers are front (floorstanders) 40Hz, centre 40Hz and rears 90Hz as set by Audyssey and so I have left them alone.

I only tend to turn the sub on (at the mains, always shown on, on the 609) for movies as there is ample bass for music but for movies the sub is lacking.

Have I setup my speakers correctly, adjusting to get a speaker channel as near 0db as possible?

Am I better tweaking the sub level by changing the db setting towards 0 or adjusting the gain on the sub?  It feels at the moment that the Fronts are dealing withg the bass.

Many thanks!

2EQ was designed for AVRs that don't have enough processing power to run higher versions of Audyssey room correction.  So, unfortunately, 2EQ does not apply filters to the subwoofer.  In the main speakers it will apply correction, but the amount depends on the speaker response.  It can make adjustments to some problems, but does not have enough resolution to catch narrow peaks and dips.  You can see the relative resolutions of each version of Audyssey here.

Hi Joel, is your sub self-powered? If so, the AVR is not using any amp power for the sub.  If you are indeed using the AVR amp for the sub then you also don't really need to worry.  Each AVR channel is separate.  Yes, they share a power supply but it's not really a big issue.

In any case, if you want to start with a higher level it's fine to do so.  Audyssey will set a trim that brings it down to reference 75 dB and the trim setting will be smaller than what you have now.  I don't expect this to make any audible difference whatsoever.

Two follow-up questions:

1.  I've ran calibration with only 3 positions, since my space allows for only 3 persons, ideally (w/ 1 on each side beside the main listening position).  Is this enough for Multi-eqXT (on an Onkyo NR809) or should I run the full 8 positions?

2.  After running calibration, if I feel the need for increasing the gain of my sub, to maintain the avr's sub trim to 3 and 4db, can I just re-run calibration at the main listening position only, or the whole setup (3 or 8 positions, w/c ever is the answer to #1)?  If 1 is enough, how do I cancel and save it after the 1st position (since it asks to move the mic to position 2)?

Thanks.

Hi Chris.

Audyssey calibration starts by asking to set the sub's level at 75db.  After calibration, it sets my sub's trim to +2.  Preferred level though has me increasing the trim by 6db to around +8.  I read though that it's best to leave the trim value between 3 and 4db so as to save the amp's power for the other channels, while utilising the sub's amp to handle the increase in power.   To achieve this, can I start Audyssey with the starting gain higher than 75db, so if I increase the trim later on by the same amount of 6db, it would fall w/in the trim value of 3-4?

Hi Scott, the acoustical problems of your room don't really care if you are playing music or movies.  They need to be fixed so you can listen to the content they way they heard it in a calibrated studio.  If you have personal preferences beyond that, these are not something that Audyssey deals with.  It's not a content EQ method, but rather a room acoustics (and psychoacoustics) correction method.

Ok thanks Chris. As i said i used all 8 points and after listening watching a couple of movies the difference is little more bass in some areas not really heard before. With music is the biggest difference. Should it really be used with music.

Scott

Scott, levels and delays are an insignificantly small part of what Audyssey does. There is no rocket science there. Anybody with a tape measure and an SPL meter can do it.  The trick is in the acoustical correction.  In the 875 you have much higher resolution filters than the 606 so you should be getting much closer to reference.  But, maybe your own preference is different. Audyssey can't really help with that... 

If you are placing the mic at ear level in the positions specified (all of them--not just 2 or 3) then you should be getting the correct acoustical calibration.  The leather sofas are not an issue.

@Chris. I have set my onkyo 875 up using the audessey 8 positions but it still sound better with out audessey on which is weird because the onkyo 606 with audessey sounded awesome.
I have been told that my leather sofas could be the problem and to place the Mic in the center of the room instead and enter the distances and levels manually after.
I understand the that i can do the distances but how would i enter the levels, should i just enter the levels it has set this time that doesn't sound right or get a meter and do it that way.

Scott

Thank you very much Chris.  This is very helpful.

By the way, Audyssey in general has greatly improved the sound in my room.  Thank you for this excellent product.  I will not buy a receiver without Audyssey.

Rob

Audyssey is not in charge of the Large/Small setting. That's up to the AVR maker.  They use 40 Hz as the decision point, so if Audyssey reports a roll off below 40 Hz the AVR sets the speakers to Large.  It's a bad idea to do this if you have a sub.  The sub is better equipped to handle the lower octave and you also get higher resolution filters in the sub channel with MultEQ and MultEQ XT.  So you should change the setting to Small after the calibration is finished.

LFE+Main is another bad idea.  It doubles the bass by sending it to the speaker and sub even if the speaker is set to Large.  That can cause boomy bass in the overlap region.  You should only use LFE mode.

Hi Chris,

Thank you for the excellent tips.

When I run Audyssey it sets my mains and centre to 'Large'.

In my Denon manual it says, "LFE: Play low range and LFE signal of channels set to 'Small'" and "LFE+Main: Play low range and LFE signal of all channels" and "Select LFE+Main if you want the bass signals to always be produced from the subwoofer".

So, it seems to me that if my speakers are set to Large, the low range and LFE signals will still go to the subwoofer provided I select LFE+Main.

Is this correct of should I just select Small for everything and select LFE? 

Thanks in advance.

Rob

From the 1st post in this thread:

"The crossover is responsible for taking the bass from the speakers and sending it to the subwoofer. That should be set at around the frequency where your speakers are no longer able to reproduce bass. This is called the crossover frequency."

Can a case also be made for setting the crossover frequency higher than the natural low-frequency cutoff frequency of your speakers? This would mean that the speakers would be relieved of some of their bass reproduction load, with the subwoofer taking over some or most of the bass reproduction duties. A crossover frequency of about 80 Hz would likely work quite well with many floor standing or larger bookshelf speakers. Smaller satellite speakers would need a higher cutoff frequency, of course.

Hi Matt,

I'm sure Ed is concerned about feeding the sub too high of a signal.  I've never seen this as a problem and always prefer the convenience of being able to precisely control the sub level from the AVR.  But, the other way is fine too.

Thanks again Chris,

Just trying to understand all this stuff and it can be confusing.  I was also reading comments from Ed Mullen at SVS that when you bump the channel trim in the AVR, that each few db increase above where audyssey sets it really puts strain on the subs.  Reason he stated is that 3 db above where audyssey sets the trim means the sub is putting out 41% more , and a 6db increase is roughly double the spl, so when I set the sub 6db hot in the AVR, it's essentially asking the sub to double the output.  If I increase the trim level by 6db, you're previous answer indicates that the spl output would be bumped in the sub channel by 6db, but he is saying the sub would be asked to double the power.  Is there a discrepancy here or am I just not understanding clearly? thanks

Yes, that's what it means.  The sub will also be 5 dB hotter than the other speakers (i.e. not how the content was mixed).

Thanks Chris,

If I set the sub 5db hotter in the trim after running audyssey, does this mean that the sub is then sitting at around 80db instead of 75db when the receiver volume is at 0? The specs on my sub rate it at 115db subject to room placement, so just trying to make sure that I don't reach that level and bottom it out.  I know you stated that most have built in protection, but I have been recently reading that a few people managed to bottom their subs out after increasing the trim in the AVR. 

Thanks

Hi Matt,

Increasing the level of the sub above the reference level set by Audyssey is a personal preference.  It's really up to you.  There is no risk to your sub as most have built-in protection.

Hi Chris,

I have the gain on my Outlaw LFM Plus subwoofer set to about 3.5 on the back of the sub.  I ran Audyssey several times on my Denon 591 and it sets the AVR trim to -8.  If I want to increase the volume of the sub, how many db hot can I run the AVR trim before risking my sub?  I currently am running it about 6-8 db hot in the AVR trim settings (which puts it at about 0 in the AVR).  What if I went as high as 12 db hot from where it was set by Audyssey, and the AVR trim level was up to +4, would this risk my sub?  I have scoured the internet for answers on how high I can turn the sub trim without risking my sub, but haven't found any answers.  Thanks!