"Official" Audyssey thread (FAQ in post #1) - Page 142

Ok, let me word this differently and clarify myself. When I run Audyssey 2EQ that is within the Onkyo SR-606 my front L/R are set to large because I do not have a subwoofer yet.
Does Audyssey not determine the frequency roll off of the speakers and if it is below 40Hz it sets them to large? Am I understanding this incorrectly?
If this is the case then 2EQ would have something to do with this setting, right?
Also, would it not be safe to say that I need to set the front L/R to small and set the crossover manually about 20Hz above the speakers lowest rated frequency response?
I apologize for all the questions! I just want to clarify as much as possible for this scrambled egg of a brain I have.

Nope. Audyssey does not adjust the treble and bass in the Pro or any other version. At least not in the sense of a treble and bass control. It creates a room correction filter for each speaker. If the room problems dictate a change in treble or bass then they will be changed. However, treble and bass controls in receivers are very broad adjustments usually done with shelf filters. MultEQ adjusts the frequency response using several hundred points that are finely spaced in the frequency domain.

Chris

[geek mode enabled]
Think of it as complex (vector) summation. The acoustical response of the combined subwoofer and satellite speakers will be the complex sum of the magnitude and phase of each response. That summation is influenced by the relative distance between the speakers (this is fixed by using the values found by the built-in MultEQ), but it is also influenced by the slope of the roll-offs of the sub and satellite. In the best of worlds, we would be allowed to manipulate the slopes as well. But since we don't get to control bass management parameters, we slide the crossover point and look for the best possible complex summation (meaning the flattest).
[geek mode disabled]

Chris

Audyssey does not set Large and Small. It determines the rolloff frequency and hands that information to the AVR manufacturer who decides what to do with it. Some use 40 Hz (correctly) and others still use 80 Hz (incorrectly) to make this decision.

In your case, however, none of this matters. If you have no subwoofer, then your front L and R speakers will be Large. They can't be changed by Audyssey or anyone else.


You can't set the front L and R speakers to Small if you have no subwoofer connected. It is physically impossible. Small means "send the bass to the subwoofer", which in your case doesn't exist. Your front L and R speakers can act as the "subwoofer" for the other channels in your system if you set the other channels (Center, Lsurr, Rsurr) to Small. That presumes that your front speakers can really handle the low frequencies better than the surrounds.

Chris

Well you could always run a "phantom" subwoofer if your primary concern is avoiding damage to your main speakers. I did this for a few days after the 20yr old foam surrounds on my mains finally gave out. You will, of course, lose the LFE and such in this configuration.

Hi Chris,

Is it literally a filter?

- Jeff

Hi Jeff,

Yes, it is a single filter (per channel). This is a difficult concept to grasp if one is accustomed to parametric EQ that is defined by the number of bands. But bands are so early 70s. The basic concept behind MultEQ is that there are no parametric bands. The filter is a set of several hundred control points. It operates in the time domain, but has an equivalent function in the frequency domain. You can think of it as a curve that is morphed so that it acquires a shape that is opposite of the room response.

Chris

Sort of like a warped of the time space continuum?

"You can think of it as a curve that is morphed so that it acquires a shape that is opposite of the room response."

Now that is a sentence. I don't know if its a good thing or a bad thing that I actually understand it.

I guess my error is/was thinking analog. But being too old for hair bands, but just right for The Band, I'm OK with that. I grok the compensating curve idea, but am at sea on the time domain thingy. Audyssey reaching out and changing the sound after it's left the driver certainly appeals to the William Gibson in me, but my Spock is at sea . . with me. I suppose I could visit your website and find more info , but could you please boil it down for me?

All filters operate in the time domain, but have both time and frequency domain descriptions. If your speaker emanated a loud, sharp click, and you listened with a mic, you would get the impulse response of your speaker and room. The Fourier transform of that is the frequency response (amplitude and phase) or filter function for your speaker+room. If you then construct a filter that is the inverse of that room response filter, then you can run your signal through the filter first, then into your speaker+room, and get a flat response out. That's the simple theoretical version - in practice there are a lot of subtleties, of course, which is why Audyssey has to be rather tricky to get something that will work in our real world.

Any similarity at all to Bose noise-canceling headphones?

With each passing post this thread reads more and more like a Star Trek episode...

Yes, a little, in that they are both trying to remove unwanted sound. Room acoustics are a much more complex problem, of course. And the Audyssey systems are nothing like anything made by Bose.

I think pepar needs to write "I will never mention Bose again in this thread" 100 times.....

Ok this is off the current topic and I'm not sure this is the place to ask this question but I figured this would be the place to start. Newbie so bear with me. When I use Audyssey on my 3808 it always sets my fronts to large and rears and center to small(for the most part). The crossovers are set to 40Mhz on the center and rears. I was always under the understanding to make all speakers small, with a sub, which I did? My question is should I change the crossovers to 60Mhz or 80Mhz? What does that do exactly?
In case you need it,my system consist of:3808 AVR,two pairs of Monitor Audio GS10's with matching center and a Epik Caliber for a sub.
Thanks for any help

This is basically what I was getting at! Thanks HDTVChallenged! Sorry, Chris, for all the confusion. I have a 3.0 set-up at this time and if I use Audyssey it detects no subwoofer and the Onkyo sets my mains(L/R) as large.
My mains, x-mtm encores, are rated down to 40Hz. I would hate for something lower or even sustained at 40Hz to do any damage. I have already spent several weeks without my "brand new" speakers and I don't want to damage them when they are returned.
Is there a lot of music/movies that get below 40Hz that are not dedicated to the LFE channel? It appears as though I will have to bypass Audyssey and manually set the receiver as if I have a subwoofer and then set the crossovers for the mains at 60Hz and just lose the LFE until I get a sub.
Too bad you can't use a tone generator during Audyssey to "fool it" into thinking their is a sub. That way I would be able to keep all of the other settings that Audyssey does so well! Sorry for the memoir!

Looking up a few posts:

"Audyssey does not set Large and Small. It determines the rolloff frequency and hands that information to the AVR manufacturer who decides what to do with it. Some use 40 Hz (correctly) and others still use 80 Hz (incorrectly) to make this decision."

40 Mhz? That's some crossover Your speakers must be the size of a hydrogen molecule that only emits sound above 40 Mhz. Sorry... couldn't resist

Your hunch is right: set all speakers to Small. Since it looks like your speakers are on the border between Large and Small per the Denon definition of 40 Hz, I would recommend going with 60 Hz.

Chris

BMAR10, repeat after me:

Audyssey does not set the speakers to Large or Small
Audyssey does not set the speakers to Large or Small
Audyssey does not set the speakers to Large or Small
....
Audyssey does not set the speakers to Large or Small





Unless you listen at insane levels for long periods of time, I don't think you are going to damage your speakers. There are plenty of people that listen without a sub and the natural roll-off of the speaker at low frequencies prevents it from overdriving. That only happens if you were to apply boost equalization below that frequency, which is not the case. MultEQ detects the roll-off frequency and does not apply any boost correction below it.


Chris

PS. Did I mention that Audyssey does not set the speakers to Large or Small

I corrected it as you were posting this response! See above! The Onkyo appears to max out at 73(assuming measurement is in db's?).
I have only been into the low 60's and that fills my smallish living room right up.
So you think if I stay in this range I will be alright keeping the Onkyo's setting of Large which is translated from Audyssey's measurement.

Yes, I think it will be just fine.
Chris

Could I please get your John Hancock right here ________ _________
so if they are damaged you can replace them!

Seriously, I appreciate your time! You are always very professional
and knowledgeable. You are one of many members that give AVS the
name it deserves. Thanks! Now enough of the a_ _ kissing, back to work!

LOL ... whatever you do, do *not* attempt to play "Ratatouille" on BD with speakers that are "iffy" down low. I'm still cleaning up tiny pieces of polyfoam surround.

Hi Chris,
to make a complex thing simple, can we say that correcting in the time domain, means cancel the echoes and reverberation af a room? This seems to me me very understandable because the echoes one can hear in a big cave or a narrow and deep valley are easly perceived as a sound that comes later in time. I think we do not realize that any room has echoes because they are very fast in a small space.

ciao

This is what really scares me. Let's say I use Audyssey and the Onkyo interprets the calibration and determines that my fronts are large full range speakers, which it does.
I pop in aforementioned BD and bam speaker shrapnel everywhere. This is a possibility for me as I have an extensive BD collection and I am sure, which you've stated with Ratatouille(which I own), that some of these dip well below 40Hz.
I am still on the fence as to how I will set-up the Onkyo and your post makes it even more difficult because I can't just be lazy and let Audyssey do it.

Audyssey determines the speaker's in-room -3 dB point and passes that to the receiver which determines the large/small setting as Chris has pointed out.

Audyssey runs its filters in the frequencies above the -3 dB point. It does not try to correct below that point and the correction rolls off, like the speaker, below the -3 dB point. You may be able to damage your speakers with Audyssey running but the reason you'll be damaging them is because you turned things up way too loud. You shouldn't have any difficulties in the low bass area due to Audyssey, but the receiver will pass the sub content to the mains in addition to the bass frequencies for their channels and that extra bass may cause problems. That isn't an Audyssey issue because Audyssey has no input into that, it's a receiver bass management issue.

It's easy to blame something like Audyssey for speaker damage when the real reason is simply excessively high volume levels because someone was a little too heavy handed on the volume control. If speakers get damaged because of excessive volume, the blame rests with the owner of the fingers on the volume knob or button as the case may be.

Audyssey killed my dynamic range.

Using Onkyo 805 with Axiom M22 Fronts & Center (91-93 sensitivity). Reference was set as 0 confirmed as 75db using the receiver test tones and source level set to 75db also confirmed using DVE limited pink noise test tones at seating position 2.5m away.

With Audessy enabled playing DVE test tones at 0 relative receiver volume gives 75db of course. Increasing to +15 reference reciever volume gives only 78db

With Audyssey disabled on playing DVE test tones: reference = 75db, and +15 reference = 88 db, more as expected.

Playing a music track with Audyssey enabled at reference, 87db peaks. The +15 setting would only get +2db more

Playing same track with Audessy disabled at reference = 103db peaks.

Why does audyssey suck the dynamics out?

And if using for movies without a sub you can go into the menu and attenuate the LFE signal for more security

Ah yes, you have stumbled into the wonderful world of Volume ICs. This is the little chip that is responsible for managing the volume, in fact it manages the entire gain structure in the receiver.

In a receiver today there are numerous functions that require headroom. These include: dialog normalization, subwoofer trim, main channel trim, downmixing, tone control, MultEQ XT.

For example, MultEQ requires 9 dB of headroom to avoid clipping. The channel trims require 12 dB of headroom to allow for the maximum setting. Downmixing requires up to 12 dB of headroom.

When some or all of these processes are enabled the maximum playback volume will be limited to the maximum headroom available in the Volume IC chip selected by the manufacturer. You may also notice that if you listen to 2 channel material you can turn the volume up higher than when you listen to multichannel content.

What trim values are you seeing after MultEQ is finished with the calibration? If one or more of them are in the high positive range then this would be part of the reason for the volume limitation that you are experiencing.

Every manufacturer deals with the volume display a little differently. In the 805, once you get past a few dB above reference the volume no longer increases if you have reached the maximum headroom of the Volume IC chip. The point at which that happens will depend on what processes are running at the time. Unfortunately, the display on the 805 continues to show the number increasing up to +15. Onkyo has told us that they will change that in future versions.

Chris

Hello,

I appreciate the reply as I am just puzzled.

Audyssey set my levels to -3.0, but when measured by the RS SPL meter was around 71-72 db, so I increased each channel by 4db to get 75db.

I would like the big dynamic sound with the evenness that Audyssey provides, but it looks like I need to choose if I want headroom or flatness.