Audyssey MultEQ Discussion Thread

**intelonetwo** · **06-03-08, 10:33 PM**

Quote:

eugovector wrote:

...If that means that I wait for someone to document how I take a third party mic, software, and documentation and do it myself, I'll do that too. I bought the hardware, I'll buy the license, and I'll do what I want with it.

I'm inthe process of arranging an interview with some folks from Audyssey. If/when that materializes, I'll explore this situation thoroughly with them.

This is the same state of mind I'm in. I agree with eugovector on this one. I'm in the process of obtaining a Audyessy Installer Kit myself.

**Bailman** · **06-04-08, 04:59 AM**

I'd load up on room treatments before I sprung for Audyssey Pro and its accompanying fees.

Has anybody actually measured an improvement in decay time?

Are there graphs?

**SierraMikeBravo** · **06-04-08, 11:54 AM**

I believe you can only change that by changing the absorptive properties of the room or the dimensions. I think what you are referring to is direct timing (the time it takes for sound to reach your ears directly from all sources) which is a function of distance. If it is not in sync, the waves will be out of timing causing a collapse in the immersive audio experience. The problem is, measuring with a tape measure doesn't always work. The DSP can induce a lag in time which Audyssey listens for and corrects.

**intelonetwo** · **06-04-08, 12:34 PM**

I think what Bailman is suggesting is that the room be physically setup properly before using any software based program. This way the software has a more acoustically sound room to work with. I could be wrong.

**intelonetwo** · **06-04-08, 12:57 PM**

Quote:

Bailman wrote:

I'd load up on room treatments before I sprung for Audyssey Pro and its accompanying fees.

Has anybody actually measured an improvement in decay time?

Are there graphs?

I have yet to measure my room, other than with Audyessy MultiEQ XT, which is on my receiver.

Treating the room effectively first with room treatments is the first step in most any sound reproduction situation. Or it should be.

I'm still trying to figure if using both the BFD, along with the Audyessy will yield benefits.

**SierraMikeBravo** · **06-05-08, 03:01 AM**

Not quite. You first need to know what you are treating for. Slapping up room treatments without knowing is not a good idea. That is not to say that some treatment isn't done right off the bat. However, before you do "tuning" treaments, you need to deal with timing first and foremost...which Audyssey does. Personally, I would treat the room afterwards if needed. Treatment is not cheap by any means either if you want it to look nice. With my room, some treatment was necessary, but not for tuning per say the frequency response. I didn't need bass trapping at all, and I used a minimum of absorption. It's really all about design and placement folks. Audyssey and treatment only provide the polish so to speak. This is why I say, you don't need to keep upgrading if the room was done right from the beginning. But, I will say this, timing is everything as well, and my room really does sound great once I polished it with Pro. I still get shivers up my spine everytime I listen to my system. It really is quite magical. But nothing is greater than the whole. Every part of the room integrates well, and each aspect played a significant role in the final outcome.

**intelonetwo** · **06-05-08, 03:23 AM**

Quote:

SierraMikeBravo wrote:

Not quite. You first need to know what you are treating for. Slapping up room treatments without knowing is not a good idea. That is not to say that some treatment isn't done right off the bat. However, before you do "tuning" treaments, you need to deal with timing first and foremost...which Audyssey does. Personally, I would treat the room afterwards if needed. Treatment is not cheap by any means either if you want it to look nice. With my room, some treatment was necessary, but not for tuning per say the frequency response. I didn't need bass trapping at all, and I used a minimum of absorption. It's really all about design and placement folks. Audyssey and treatment only provide the polish so to speak. This is why I say, you don't need to keep upgrading if the room was done right from the beginning. But, I will say this, timing is everything as well, and my room really does sound great once I polished it with Pro. I still get shivers up my spine everytime I listen to my system. It really is quite magical. But nothing is greater than the whole. Every part of the room integrates well, and each aspect played a significant role in the final outcome.

Certainly, I do not believe anyone here believes you should throw up room treatments indiscriminately. Nor has anyone here suggested that path be taken.

Seems as though the way I have learned to deal with room acoustics, and the way you have learned to deal with room acoustics are different.

I have been taught in the traditional fashion. Which, briefly, is to say that EVERY room will have first reflections, and other bass challenges to deal with. And to deal with those problems and other room problems you should address them methodically in the following order:

Proper Placement & Setup
Room Treatments
Software Based Correction (Audyssey, YPAO, Sample Rate Systems (SRS), etc, etc.)

I'm a proponent of Audyssey. I also know that using room treatments properly beforehand, can only make the Audyssey system work better.

**Bailman** · **06-05-08, 10:16 AM**

Quote:

SierraMikeBravo wrote:

I believe you can only change that by changing the absorptive properties of the room or the dimensions. I think what you are referring to is direct timing (the time it takes for sound to reach your ears directly from all sources) which is a function of distance. If it is not in sync, the waves will be out of phase causing smearing. The problem is, measuring with a tape measure doesn't always work. The DSP can induce a lag in time which Audyssey listens for and corrects.

Mike,
Have you read this thread, specifically my post numbered 12?

A recap for all:

http://www.realtraps.com/art_audyssey.htm

I understand Kal has the Onkyo Prepro with the MultEQ XT capable of the Pro incorporation which he was going to obtain and review. What I do not know is what version was being used by his friend Ethan.

Ethan wrote:

"Recently several products have appeared claiming to do even more than EQ by using sophisticated DSP (Digital Signal Processing). They claim not only to flatten the frequency response, but also to reduce modal ringing and early reflections, and to do so successfully over the full range of audio frequencies for multiple seats in a room"

"Unfortunately, the popular audio press gushes uncritically over products like these, printing press releases as fact and never actually testing the validity of manufacturer claims. The appeal of a small electronic device that claims to replace large and visually imposing acoustic panels is undeniable. But wishful thinking does not make it so!"

"Even the vendors themselves offer no real proof that their products work as claimed. I emailed Audyssey on October 29, 2006, regarding the technical descriptions and graphs shown in THIS series of pages on their web site. I asked if they had any data to support their claims of reducing ringing, and I also asked for clarification about how the tests on their site had been performed. For example, how large the room is and how far the measuring microphone was from the walls. At the time of this writing, 3-1/2 months later, I have yet to receive a reply from Audyssey. "

"Audyssey claims to flatten the response and reduce ringing over an area large enough to encompass multiple seats, so I measured at three adjacent locations on Kal's couch. It turns out this was not necessary because the MultEQ was unable to reduce ringing even at the same place it was calibrated for. As you can see in Figure 1 at left, the main improvement is a 6 dB reduction of the lowest response peak around 35 Hz.

The graphs in Figures 1 and 2 show not only the raw low frequency response, but also the individual decay times for each peak frequency. This type of graph is called a waterfall plot, and the "mountains" come forward over time to display the decay times at each frequency. You can read a more complete explanation of waterfall plots and the ETF software I used..."

Now since there is no proof that Audyessy improves the decay times/ringing in the low end as they claim, why throw away the Behringers personalization capabilities for our subs? I had/have taken mine out of the equation BTW and I myself have noticed improvements but also immediately acknowledged sacrifices in the low end articulation and slam which the BFD could re incorporate. I am not so sold on the Audyssey implementation in our systems.

Has anybody actually measured an improvement in decay time with Audyssey?

Are there any graphs?

Here is a product that does what Audyssey claims to do and they have graphs that apparantly show the results.

http://www.dspeaker.com/en/technolog...urements.shtml

Now compare those graphs with Audyssey's graphs.
http://www.audyssey.com/technology/graphs/graph1.html

**Bailman** · **06-07-08, 04:36 AM**

Here is a representation of Audyssey in a room. It may be a poor one but it is the only other graph I could find at this time that shows what I have been trying to discuss and what I've been experiencing.

Before:
http://www.avsforum.com/avs-vb/attac...1&d=1150342504

After:
http://www.avsforum.com/avs-vb/attac...4&d=1150342539

Notice the decay times have worsened. It is the opposite of what is advertised. Ethans web page in my other post shows the same type of increase.

**Wayne A. Pflughaupt** · **06-10-08, 04:33 PM**

Here are those AVS graphs:

Before
before_wf.jpg

After
after_wf enahnced.JPG

I'm not sure that ringing is actually worse with the "after" graph.

Note the highlighted frequencies appear to be at ~120 Hz, ~60 Hz, and ~30 Hz. Most likely these are artifacts generated from some source other than the sound system: An air conditioner kicked in, someone turned on a washing machine or microwave oven, etc. (Note that 120 and 30 Hz are harmonic frequencies of 60-cycle noise.) You can tell it's not ringing because it's a steady-state, constant signal. Ringing from a resonating audio frequency isn't going to drone on and on forever, it's going to continually drop in level and eventually disappear - like everything else in the graph does.

Another problem with the graphs is that they show only a 30 dB window. Signal levels should be kept high for waterfall readings. Note in Ethan's graphs at the RealTraps link that its bass peak is 60 dB above the graph floor. When it comes to waterfalls, Ethan knows what he's doing, so follow his example!

Apparently even professional people who should know better have trouble analyzing waterfalls. Consider a couple from the DSPeaker site Bailman linked above:

p_d7fa838944.jpg

p_e0550e60df.jpg

You would think these folks should know what they're doing, but look at the lower graph: By the time they're done equalizing, the signal is a mere 20 dB above the graph floor.

And look at the graph's lower limit - 50 dB? What, is that for people who run box fans in their HT room? Raise your hand if the noise floor in your room is that high.

(I could comment further, but rather than sidetrack the thead you can see more that I recently presented on the subject of waterfalls here.)

I'm confident that Audyssey is a dandy product, and probably the little box from DSPeaker as well. It's a shame they label them as "time domain" products that improve sound by reducing ringing. They may do a little of that, but primarily they're improving sound by smoothing or flattening response - i.e., reducing peaks and valleys with counteracting filtering. That may or may not carry an improvement in the rate of signal decay (which must be shown if you want to claim an improvement in ringing, not merely a reduction in gain that makes a waterfall "look" better to the untrained eye). In fact, it can even make a waterfall look worse at some frequencies where boosts are enacted (again, to people who don't know how to properly read them). But IMO the improvement in sound ultimately comes from minimizing peaks and valleys, regardless of what happens to ringing. For instance, try applying equalization to your headphones, if they need it. If it makes them sound better, it was purely response smoothing - there was no ringing factor involved.

One thing that does trouble me with Audyssey is the way it appears to equalize every nook and cranny out of response (the orange line represents the equalization that will be employed):

The range between 1-3 kHz, for instance: While all those little up and down jags look bad, the truth is you really can't hear that. The ear does not hear the same way a mic "does." For instance, if you add a coffee table to your room you may see a change in a response reading, but everything sounds the same to you. So I'd be concerned that all that equalizing could degrade sound quality, but I'll leave that judgement to the folks who have actually used Audyssey.

Regards,
Wayne

**SierraMikeBravo** · **06-11-08, 04:00 AM**

Hey Wayne,

Audyssey doesn't try to flatten out every nook and cranny. The amount of data points used for correction drops off signficantly above the midrange. Also, not sure what mic people are using for those graphs, but I have also said before that using the RS meter for anything (other than maybe nearfield environment....maybe) is a waste of time. It isn't accurate for anything. The smaller the mic grazing area the better (ideally 1/4 inch or less). If these graphs were taken with less than ideal equipment, it brings serious doubt to the validity of the graphs. I would want to know how the measurments were taken and with what equipment before I lend them any credibility. As with anything in life, you need to prove it to yourself. Don't take other people's word for it. Especially since we are talking science here.

However, I do have one question, what good would equalizing headphones do since all problems associated with frequency response are due to the room itself? A speaker placed outside without the confines of walls should theoretically reproduce sound perfectly flat. This is one reason why large venue acoustics are so much different than small room acoustics. Just my 2 cents.

**intelonetwo** · **06-11-08, 11:09 AM**

Quote:

SierraMikeBravo wrote:

However, I do have one question, what good would equalizing headphones do since all problems associated with frequency response are due to the room itself? A speaker placed outside without the confines of walls should theoretically reproduce sound perfectly flat. This is one reason why large venue acoustics are so much different than small room acoustics. Just my 2 cents.

I believe Wayne was just using headphones as an example for this conversation.

At the end of the day time domain is not seen to be greatly affected by either the Audyessy, nor the DSPeaker. Again the peaks and valley's are touched in varying degree based on frequency, a la smoothing, etc.

**Bailman** · **06-11-08, 02:58 PM**

OK Wayne,

You done convinced me.

I guess I will rearrange my room (was gonna do this anyway) back to the way it was
and attempt to get this "dandy" product to shine like it does for so many others.

Thanks for all your time

BTW, the other thread going on hear @ DaShack was way cool...
a bit over my head

but I absorbed what I could.

**Wayne A. Pflughaupt** · **06-22-08, 05:53 PM**

FYI, John has posted a review of the DSPeaker processor.

http://www.hometheatershack.com/foru...tml#post103808

Regards,
Wayne

**tdamocles** · **07-06-08, 05:36 AM**

If I have 2 subs setup in a room and run Audyssey MultEQ would it be able to equalize the sum of both subs simultaneously to a somewhat of a nice equalization curve? I've run it (on an Onkyo tx-sr805) and have run REW afterwards and must say that it did a good job of equalization with 1 sub.

Does Audyssey MultEQ equalize to 10hz on an Onkyo?

**SierraMikeBravo** · **07-06-08, 05:34 PM**

If your sub is capable of going that low...it will. Pulses are sent across the entire frequency spectrum. However, very few subs go that low with any significant output. Most of the very good subs have a steep dB slope below 20 Hz. Most subs however, have steep slopes in the 30 Hz range or even higher when you get into the not so good subs.

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