"Official" Audyssey thread (FAQ in post #1) - Page 31

I think you are making things far too complicated. I'll make it simple: there's really no situation where "double-bass" is necessary (and I'll even go as far to say that for most situations, it's undesirable). You do NOT need double-bass to prevent loss of information. If your satellites can handle all the way to 20hz, leave them as "large". They will handle all the bass that is encoded into their respective channels, and the sub will handle the all the LFE (assuming you haven't low-passed the LFE below 120hz). If your satellites CAN'T handle down to 20hz, pick the lowest crossover point that is above the lowest frequency they can comfortably handle, and the sub will handle everything below that, plus the LFE channel. All double-bass does is cause the lowest frequencies to be duplicated in the sub and the satellites. IMO, that can do a lot more harm than good.

CHRIS: There's something that's been nagging me in the back of my head that I didn't want to bring up. But the bass management issue has been beaten so bad, perhaps a change of subject would be welcome. I understand the point about Audyssey applying correction to each channel down to that speaker's -3db point, and therefore we can fine tune the crossover points after calibration, if necessary. But I thought that Audyssey also applied correction in the time domain... I have been of the assumption that this meant that it could/does correct for any phase anomolies created by the crossover network. If this is true (?), wouldn't changing the crossover point screw up those settings? Interestingly, I have the same satellites all around (NHT 1.1), and the front L-C-R aren't that far apart (maybe 4ft between each one). Yet Audyssey detects the L & R as being full range (yet I know they aren't), and the center as only good to 150hz (yet I know I've had satisfactory results previously with it set to 80hz).

This I agree with. It is your previous statement that is misleading. -


"No. "Double Bass"/"LFE+Main" works only, IF your speakers are set to LARGE. And if these speakers are set to LARGE, there is neither a cutoff nor a crossover"

I asked this in the 9.8 thread, but this is really where it should be asked: Is the Audyssey improvement measurable/quantifiable, or does it not go beyond "sounds better/I like it better?" Not necessarily that anything like it is part of the secret sauce, but in the back of my mind is "Aphex Aural Exciter" . . .

Sure it is. Get some test gear and measure the frequency response with and without Audyssey. Bingo, it's quantified.
Well, the graph can't tell you how it sounds to you. Only your ears can do that.

Anything and everything are measurable. Does the average or even the dedicated home audio/theater afficionado have the right sort of instrumentation and recording capability? Highly unlikely. And once measured and recored properly, how does one "analyze" what is there.

I let audyssey do its thing on my Denon and it seemed like it didn't hurt anything too much. I would have liked to be able to apply a bit of a curve like the X curves in MCACC.

2 questions: ( I have a Marantz 8002 )
(1) Audyssey EQ seems to be disabled completely for 44KHz CD music and SACD play-back. Is this a Audyssey decision or a Receiver decision ? When the CD is sampled at 48KHz, Audyssesy becomes effective.
(2) I am not experiencing the great day-and-night difference with Audyssesy that everyone is talking about. What may be wrong ?

THanks. I am still trying to understand.

Try this.
Place your sub on the seat of your primary listening position, maybe propped up to try to have the driver/port close to ear level. Play your Boston Acoustics (or whatever). Get down on your hands and knees and crawl around the floor until you find the spot that gives you the best bass. This where you place the sub. Beware of spots that may give you boomy bass. You want clean tight bass.

This procedure isn't foolproof, and you should also try the test with your sub in the other listening positions and hopefully still end up with the same sub location. It's not the perfect solution, but at least it's a start, and definitely better than just locating the sub for asthetic reasons only.

BTW, you must defeat any previous Audyssey settings before you do this, then re-run Audyssey after you (and your wife) are happy with the new sub location. It may help to also trim down all the speakers (not the sub) so they don't produce any audible sound while listening to the sub.

Darin,

A proper crossover network should not introduce phase anomalies. Linkwitz-Riley 4th order (two cascaded 2nd order filters) is the theoretical optimum. It introduces 0° phase delay (technically 360°, but that is the same as 0°).

Yes, Audyssey filters do operate in the time domain. That means they are trying to deal with reflections that may arrive later in time than the direct path and smear the signal.

It is not surprising at all that your identical speakers are coming up with different values for the -3 dB point. If you have an Onkyo then MultEQ will report Full Range if your speakers - 3 dB point is below 80 Hz. Very believable for your speakers. It is not our decision to use 80 Hz as the criterion. As for the center, I suspect there is some cabinet or wall closer to it that can cause a big bump at 100-200 Hz. That's probably what MultEQ sees when calculating the slope to find the -3 dB point.

Regards,
Chris

I'm not sure about how you are connected. If you are going in through the analog multichannel input then Marantz (and nearly every manufacturer) does not have A/D converters on those inputs. So, the incoming signals never become digital and they never get seen by the DSP chips. This means that there is no Audyssey, no digital bass management, etc.

Regards,
Chris

Sorry that I didn't provide enough info. The Player is PS3. And it is connected to the receiver via HDMI.

As far as I know, Marantz applies MultEQ filters to all incoming digital sources. So, I am not sure why you are seeing this. This is probably best answered by Marantz...

Chris

So Chris, you are saying that Marantz (and presumably Denon, Onkyo, etc) *ONLY* apply MultiEQ with *DIGITAL* inputs, and *NOT* with analog inputs?

I integrated my Denon 3808CI (initially planning to use only for 5.1 home theater) into my high-end two channel setup by feeding my Modwright tube pre-amp into the analog CD inputs of the Denon, then feeding the Denon pre-outs to my two-channel (SS) Belles amp. Switching the Denon EQ from OFF, to Audyssey, finally to Audyssey Flat, *DEFINITELY* improves overall sound. If the above is true, then what's going on??? (The improvement was so good, that I was able to dial my ML Summit woofer adjustments back to their default setting, where I previously had to cut them -3 dB at 50 Hz to tame room bass nodes).

Is it possible that Denon is just copying the MultiEQ settings to be applied (as best they can) in the analog path??

No, it's OK. Chris is talking about the multichannel analog inputs, not the CD input - the CD analog input is digitized by an A/D converter, so can be processed by the full DSP of the Denon, including Audyssey. That's why I suggested using that input.

Whew! I thought I was losing it, and ready to turn in my audiophool calling card!

Fyzziks, thanks again for your original brilliant suggestion/fix!

How is it implemented by Marantz?

But what is wrong with this statement?
I hope you agree, "Double Bass"/"LFE+Main" works only, IF at least one speaker is set to LARGE.
I hope you agree too, if a speaker is set to LARGE, there is neither a cutoff nor a crossover for this speaker as it will get the full range of its channel.

Maybe you mean the "crossover" needed for "Double Bass"/"LFE+Main"?
In this case, I admit my statement could be misleading.
But my statement was related to the following sentence: "So with Double Bass "off", the -3dB point for the speaker acts as a "cutoff", not a "crossover"." So in this context it should be clear what I meant.

Yes I agree and misinterpreted the first statement. The phrase "full range of its channel" makes it clear. I am now using Audyssey, fronts large at 80Hz crossover and LFE+Main and am satisfied.

Chris

Thanks for the info on LFE (120hz). I have changed mine. Great info.

Brad

Chris:

Do you recommend that those of us with projectors for a display, run Audyssey with the projector off (so the fan noise of the projector doesn't interfere with Audyssey calibration)?

Of course, this means relying on the receiver display panel to run through the process -- rather than the screen.

Yes, please do not have the projector running. It's usually right above the mic and that causes all kinds of problems. I often use an old DV camera LCD screen and run the composite monitor out of the receiver to it. Simple and it gives you the full OSD rather than the front panel display.

Chris

I agree with that. In my case, the 60" plamsa is off (slight buzzing), the heating in the house (pipe noise), the cat is locked out of the room and hopefully stays asleep and I try not the breathe too hard. If my area is being used as a flight path from London Heathrow (Sunday afternoons, great!) then I don't bother. Pretty much any noise will knock the setup off slighty, as I have discovered over time and a number of occasions.

Hi Chris,
Thanks for helping me with original setup. Things have changed slightly now.
Have new Paradigm CC-190 center

specs: Design 4-driver, 3-way center channel,
MagneShield™††
Crossover(s) 2nd-order electro-acoustic at 2.8 kHz, 2nd-order electro-acoustic at 300 Hz (bass drivers)
High-Frequency Driver(s) 25-mm (1 in) H-PTD™ dome,
ferro-fluid cooled
Midrange Driver(s) 90-mm (3-1/2 in) M-ICP™ cone,
25-mm (1 in) voice coil,
ferro-fluid cooled, GRIP™ chassis
Bass Driver(s) Two 140-mm (5-1/2 in) carbon-infused polypropylene cones, 25-mm (1 in) voice coils, GRIP™ chassis
Low-Frequency Extension* 54 Hz (DIN)
Frequency Response:
On-Axis
±2 dB from 90 Hz - 20 kHz
30° Off-Axis ±2 dB from 90 Hz - 17 kHz
Sensitivity - Room / Anechoic 93 dB / 90 dB
Suitable Amplifier
Power Range
15 - 120 watts
Maximum Input Power† 80 watts

New Fronts - Paradigm Titans
specs
Design 2-driver, 2-way bass reflex,
quasi-3rd-order resistive port, MagneShield™Optional††
Crossover(s) 2nd-order electro-acoustic at 1.8 kHz
High-Frequency Driver(s) 25-mm (1 in) H-PTD™ dome,
ferro-fluid cooled
Bass / Midrange Driver(s) 190-mm (7-1/2 in) M-ICP™ cone,
25-mm (1 in) voice coil, GRIP™ chassis
Bass Driver(s) -
Low-Frequency Extension* 39 Hz (DIN)
Frequency Response:
On-Axis
±2 dB from 65 Hz - 20 kHz
30° Off-Axis ±2 dB from 65 Hz - 15 kHz
Sensitivity - Room / Anechoic 93 dB / 90 dB
Suitable Amplifier
Power Range
15 - 100 watts
Maximum Input Power† 80 watts
Impedance Compatible with 8 ohms
Internal Volume 17.1 L / 0.60 cu ft

Paradigm Cinema 70 for surrounds
specs
Design 2-driver, 2-way acoustic suspension,
mineral-filled polymer enclosure, MagneShield™††
Crossover(s) 3rd-order electro-acoustic at 2.0 kHz
High-Frequency Driver(s) 25-mm (1 in) PTD™ dome
Bass / Midrange Driver(s) 90-mm (3-1/2 in) ICP™ cone
Bass Driver(s) -
Low-Frequency Extension* 85 Hz (DIN)
Frequency Response:
On-Axis
±2 dB from 125 Hz - 20 kHz
30° Off-Axis ±2 dB from 125 Hz - 15 kHz
Sensitivity - Room / Anechoic 87 dB / 84 dB
Suitable Amplifier
Power Range
15 - 80 watts
Maximum Input Power† 40 watts
Impedance Compatible with 8 ohms
Internal Volume 1.5 L / 0.05 cu ft

Paradigm CT-sub
After running Audessey calibration on Denon 2808ci came back with the following:

Front - large
Center - small
Surrounds - small

Subwoofer lfe&main
Crossover
front - 40hz
center -60hz
surround -150hz
lfe -80hz

Should I change fronts to small, lfe to 120hz?
Should I change crossovers on the front, center or surrounds?

Thanks for any advice from all who contribute to this forum
Phil

I've just registered with this very impressive forum.

I have a Denon 2807, and before retirement had some professional involvement with motion picture sound recording and reproduction techniques. In reading the material on the web in general, as well as this forum, I find very little about what Audyssey actually does in terms of transducer and room equalization.

I'm clear that it normalizes time delays of the several speakers, does something about equalization, and in some way averages the responses in a number of different listening locations. Whatever it does requires little input from the user, just push the buttons and move the microphone around.

I have no real understanding about the nuts and bolts of Audyssey's spatial averaging or equalization. In the 2708 system,the manual says the first position is given extra weight, and should be the preferred listing position, but provides no further details. Something is said about using only direct path response for the measurements, but not how this is done. The only way I can envision is some kind of time gating, but I don't know know to implement this with the FM sweep test chirp used by my receiver. In any event, I would not think it possible to optimally correct all positions at the same time.

I have some concern with the emphasis placed on wide-band (noise or FM chirp) analysys. Frequency response is by nature narrow band. You want to know what the system does with a high degree of resolution. A narrow band or high Q resonance takes time to be excited and to decay. For this reason it is less obvious with wide band measurements, but nonetheless real. It's important to view these things correctly. A narrow resonance is not as easily heard with music or speech as is a broader resonance. Perception seems more proportional to the area under the curve. ("see Audibility of Resonances" chapter at: http://www.infinitysystems.com/home/...rt_science.pdf
There are several interesting papers concerning loudspeakers and room acoustics here.

The Audyssey web site (www.audyssey.com/technology/graphs/graph1.htm)
shows a series of graphs, and states the response is measured at "hundreds of points" and a complementary equalization curve generated.

Well, I counted all the points in the graph they showed.and I got 173, probably +/- 10. 77 points between 30 and 150 Hz, about 90 between 150 and 10KHz, and 6 between 10 and 20 KHz. I've got to believe that this, if it represents an actual system, it is the very best one available. It is not said if these points represent the sum of all possible measurement points, or if measurements are in fact made at each point, and the results saved for further computation.

Another page (www.audyssey.com/technology/multEQ_products.html) shows a chart with comparisons between 3 versions of Audyssey. There is a little confusion here also. The 3 versions are MultEQ-XT, MultEQ and 2EQ. Denon shows the 2807 as using MultiEQ-XT, but that is contradicted as 6 measurement positions are provided in the 2807 but the site text specifies that in the non-professional, reciever version of -XT there are 8 measurement positions. It is the stand-alone device, requiring professional installation that has the highest performance shown on this site. This suggests that the 2807 version more resembles what the site describedsas MultEQ.

If I use the comparisons in the Audyssey chart, for a MultEQ version I get about 10 measurement points "for the subwoofer" for which I am assuming a 150Hz crossover. This corresponds with the counted 77 points shown in the graph for the full-bore version. The rest of the spectrum gets 16 measurement points. This is roughly comparable to a 1/3 octave equalizer, and some measurements of before and after and compensation curves published on this site tend to support that kind of resolution performance. I don't remember seeing any information about the magnitude of boost or cut available, but the published graphs suggests it is cut only.

Now, Audyssey says it is neither a constant or variable Q graphic, or a parametric equalizer, but nowhere can I find what it is. It seems implied that the implementation is of the weighted tapped delay type, and is linear phase (constant delay) in its time domain response. I can find no hard data about the resolution, spacing or number of measurement or compensation points, especially in Audyssey's simpler versions.

Possibly this lack of information is due to business reasons, but it is not obvious what they are. Other traditional equalizers are available in linear phase form, and their pros and cons are pretty well understood. I know I would feel I could better use and evaluate Audyssey if I had engineering data to supplement the almost entirely subjective opinions I now have. The nearly automatic operation is certainly helpful, but not unique. A possible source of information is the US Patent Office. Does anyone know if Audyssey is covered by a issued patent, and if so, its number?

I would appreciate comments, or any available information. A response from Audyssey, or any of their licensees would be most valuable.

Donald

Hi Phil,

I would change the fronts to Small and 60 Hz and the LFE to 120 Hz. Everything else seems fine.

Regards,
Chris

Hi Donald,

The first position is where the time delays are calculated from so it's important to start in the main listening position. It is not given extra weight in calculating room correction filters.



Audyssey does not correct only the direct path. MultEQ looks at patterns in the time domain responses and classifies them into clusters based on the acoustical problem similarities in those patterns, typically in 3-5 groups. A representative response is created from each cluster, and a final response is then created from grouping the representatives. That response is then used to create the EQ filter using a process that is based on the mathematics of pattern recognition and fuzzy logic. This allows correction of multiple positions simultaneously. In fact, it performs better than traditional averaging because it weighs the problems in each location according to how important they are, whereas averaging gives each measurement the same weight.




This is an important topic that I teach in my graduate course at USC. The signal used is a specially-designed chirp that runs through the entire frequency range with a particular time weighting. The method is based on system identification that allows a linear, time-invariant system to be characterized by its impulse response. The result of the measurement is a response that consists of several thousand points, more than enough to see even the narrowest of resonances. The key is to then create spatially-weighted filters in the time domain and not the frequency domain as is done with traditional parametric equalizers.


These graphs are illustrations only. The actual filters have several hundred points.


MultEQ XT says "up to 8 positions". The reason for 6 in the 2807 is because of memory limitations in the DSP architecture that does not allow us to store 8. This is really not a big difference for typical home listening rooms. The filter resolution and the subwoofer resolution in the 2807 is identical to all other receiver-based MultEQ XT products.


MultEQ is boost and cut as it is performed in the digital domain and we work with the manufacturer to ensure that the gain structure is properly designed so that we do not have problems with clipping. An analog equalizer that boosts without knowledge of the gain structure could clip. Also, a parametric equalizer that boosts in very narrow bands can also clip, but more importantly causes large phase variations that result in audible artifacts.


The MultEQ filters are specially-designed FIR filters operating in the time domain. They are minimum phase for reasons that are too lengthy to discuss here. We have published more than 20 technical papers in the IEEE journals, the AES, and JASA as well as a book that covers a great deal of the math involved.

I hope this helps answer some of your questions.

Regards,
Chris

I have a doubt.

When running the auto set up, can I move the mic after the pings or should I wait fot the indication to move it? I think the measuring happens only while pinging and the time from the last ping to the instruction to move the mic is used to store the measures detected, but I may be wrong.
Thanks for clarification on this matter.

ciao

Hi Chris,
in Phil's settings, if I am not mistaken, the Double bass function is enabled and all the contents below the crossover frequencies indicated in the post for front center and surrond will be copied to the sub.

In my system, if I allow the Double Bass, the bass sounds muddy and too much evident, like if they were not melted together with the mains speakers.
I do not think is a matter of localization. While listening you can hear a surge of bass content not related to anything else in the sound. I have hard time explaining this in english. I tend to exclude a dip because I have run Audyssey very carefully.
I simply do not uderstand why this happens.

I understand is tough, but could you try to guess out why and point me in the right direction?

Thanks

enzo

Applies this also to the 3806 and 4306?

Hi Im just about to puchase the denon avp-a1hd pre-amp and noticed it can accomadate the audyssey pro.What I wanted to know I have just recentley had my Room calibrated by a HAA speacilist and have a good understanding now on whats involved in HAA calibrations.What does a professional audyssey pro calibration involve? I don't want to pay for something that is similar to a HAA calibration. I was told that audyssey can bring down the peaks but cannot djust the nulls is that correct? Also Audyssey wasn't recommended by the HAA calibrators