For anyone who is into this quirky pastime, this is an excellent, 'must watch' video that explains so much from 'The Guru' himself. It is not overly technical so even I can understand it all. It surmises why there is so much heated opinion & BS out there, especially on some forums.

https://www.youtube.com/watch?v=zrpUDuUtxPM

Ian wholeheartedly recommends it & summarized the content to me:

Great video. It covers exactly what matters to what we hear and how to make a great sounding speaker. The salient points:

• Listen testing must be done blind.
• The frequency response, as measured all-round the speaker in an anechoic chamber, are what tells us how a speaker will perform in a blind listening test.
• This cannot be accomplished without a proper laboratory to do it in.
• Audible resonances are visible in the anechoic amplitude response graphs.
• Consistency of one speaker to the next in the manufacturing process is critical and rarely done.
• Room correction algorithms will not correct a bad speaker design. They can ruin a good one though.

This kinda dispels some of the 'Myths' that have been spouted in articles elsewhere. One 'Myth' pooh-poohed the notion that a manufacturer having a sophisticated anechoic chamber was advantageous to properly designing speakers. This is laughable. The clear advantage to having this essential equipment is repeatedly reinforced throughout this talk.

From what I gleaned from the video, I am now rethinking my use of Audyssey correction in my HT. Interestingly, Axiom has not recommended room correction EQ use as well...

TAM

Thanks TAM. Great vid. His presentation was much more enjoyable than the paper of the same name. -science in the sevice of art (also very informative). I really need to read his book.

Ok, so maybe someone watched and is thinking "oh no! I own loudspeakers that have issues he highlighted." Its alright, Salon 2s are expensive.

There are a couple of his points that I think were presented as showstoppers, but could be minimised by room treatments. Flat off axis response and a linear directivity behavior are not entirely essential to reference sound (at the MLP). Directivity/off axis problems can be helped by appropriate first and second reflection point treatments. Setting up rooms lengthwise also reduces extreme off axis listening positions.

Also, the timbral contribution of a room at middle frequencies becomes less problematic when treatments are employed and RT60 is reduced to appropriate levels. This increases perceived dynamics and reduces listening fatigue as well.

There are a ton of reasons why an AVR auto room EQ is a bad idea. He hit the nail on the head with a "a microphone doesnt compare to 2 ears and a brain". If you need more convincing search Paul Hales' appearance on home theater geeks. A good one.

I would love to see day 2 of the lecture presentation. Again, thanks TAM.

Both of my rooms are very oddly shaped (one above the other on the second floor) where my systems sit in a large window alcove & fire across the space at about a 45 degree angle.

If nothing else, standing waves & nulls seem to not happen but the mid & higher freqs might be reflecting in a very unique way that might be hard to measure. Who knows??

Anyway, sounds good to me...

TAM

Tom, thanks for linking Dr. Toole's excellent presentation. It was fascinating as he pointed out flaws in many highly regarded(and very high-priced)speakers, including the KEF 105.2 which he specifically named.

You should also consider studying his book "Sound Reproduction", which I've quoted several times here over the past few years.

One of the other points he made was that reviewers are really just reporting on their own adaptability to a sound of a speaker over time, rather than the speakers performance. Very interesting.

I have found this to be true after hearing some of the highly regarded speakers they reported on didnt sound too great to my ears. (KEF Q900 comes to mind.). However one of the biggest let downs I listened to was a "perfectly designed" speaker by Andrew Jones. Maybe I am less able to adapt than others.

I think that it may have been Randy (SirQuack) that said it first, or at least who I remember saying it first, and who knows how good my memory is... Speaker break-in isn't so much as changing how a speaker performs, but giving our ears time to adjust to the new sound of the speaker.

I suppose just to muddy the waters a little bit more on this issue, as part of its design philosophy, "Totem Acoustic" points out that they tune their speakers by ear and don't use an anechoic chamber at all.

Some measurements of their 'Dreamcatcher' model:

http://www.stereophile.com/content/totem-dreamcatcher-loudspeaker-measurements

Despite not being designed in a chamber, many people like them despite less than ideal measurements. They seem to be quite successful in the marketplace. Several people posted that they have a 'house sound' that is not necessarily ideal but pleasing to many.

So again, although measurements are supremely important, it all comes down to personal, subjective preferences on what a person buys...

TAM

I love my Dreamcatchers and can really find no fault with them for 2-channel, casual listening to music in the living room. They are not M80s in terms of SPL or "presence" but they are sweet to listen to nonetheless.

As for comparisons to the M3 and M22, I can only compare them to v2 of both of those models. To me, the M3 sounded "fat", the M22 sounded "thin" and the Dreamcatcher sounds "balanced". It feels like nothing is missing and I don't use a sub. As for price, I don't know - I picked them up as part of a package deal that I couldn't pass up.

My buddy picked up a pair of these for $90 on sale: //www.visions.ca/Catalogue/Category/Details.aspx?categoryId=160&productId=25450&sku=SPBS22LR.

I had these Pioneers in my place for a few weeks. If you take the covers off of these, you have no need for the Dreamcatchers.

My M3s that are placed on stands in 'bass reinforcing' corners in my room also sounded 'fat'. Plugging the port nicely cured that anomaly to where they are very neutral now.

BTW, other speakers sounded 'fat' there also. So it is not the speakers' fault in my case...

TAM

TAM -- Thanks for the link to Dr. Toole's talk. I finally had a chance to watch it today. Very interesting & I learned several things. I was looking forward to his comments "if there is time" on how to deal with room coloration in the low frequency range, but apparently there wasn't. Bass traps, I would guess, but it would have been nice to hear his take.

On a side note, my copy of Pohlman and Everest arrived, but no time to dig in yet.

I did some experimenting with Audyssey this afternoon. I got my trusty RS Analogue SPL Meter out, turned Off Audyssey & played the Denon AVR Test Tones. I set all of the levels at 75 Db at my MLP using the meter vertically. As contrasted to the LF that was right on 75 Dbs, the CC & RF Channels had to come up a couple of DBs & the Surrounds even a bit more. Subs were OK & were nicely shaking things.

I then played in Surround Mode one of my favourite concerts at -15 Db (peaking at 90 Dbs at my MLP) - Eric Clapton & Steve Winwood 'Live in Madison Square Garden' DVD.

I repeatedly cycled through the various Audyssey modes & concluded that whenever it was ON, it added some brightness to the overall sound. It was quite apparent that when Winwood was speaking in an interview between tracks that his 'S'es were more prominent. When looking at the EQ graphs, I found that Audyssey indeed had added some higher end boost to my room. Kinda dispels that notion that Axioms are overly bright, ha!

So as others have recommended, Audyssey is OFF, at least for now. Without it, there is a smoother presentation for music; however, I will have to test it out on a movie or two to see how that sounds...

TAM

Tom ,

FWIW which is probably not much, I have never really found any benefit from using Audyssey. People have posted different methods for running Audyssey along with reason's why they thought it was better and I have tried them all without much success. I have since moved to separates and my Pre/Pro has Dirac Live full and I have found it to be a nice improvement. Nothing ground breaking , but the cohesiveness during a movie is much improved. I say if it sounds better to the user then they should use it but if not don't feel as though you have to use RC just because its there.

Every room I have been in over the last 8 years, from over-damped, under-damped to everything in between, and speakers of all types, Audyssey served to "clean up" the sound. Everyone who has listened with and without Audyssey in those rooms is in agreement. Now that's not to say there may not be any venues where Audyssey messes things up; I just have not experienced them and neither have the people I know.

For those of you that may remember, bass and mid-bass was a huge problem in my basement space. I spent over a year moving my sub around, trying different settings, etc. Nothing worked in my "bright" space. In 2009, we renovated upstairs. We moved some stuff downstairs temporarily to get it out of the way. My room was no longer bright and I took the opportunity to experiment with the bass. I became so frustrated, I just gave up. For many years I listened like that. Then I got an Onk with XT32 because my 2000-vintage Denon died. Even though I heard the benefits of Audyssey at other venues, I didn't hold out much hope. What do you know? It worked! The only fiddling I had to do was to change the setting from "Music" mode to "Movie" mode. I find "Music" mode exaggerates the high end. When I turn on Audyssey in my space, the clarity is like night and day - no critical listening required.

So I am finally very happy with my bass and mid-bass and I owe it to Audyssey. If I was a speaker designer though, I might feel upset. If I was pulling my hair out taking thousands of curves and endlessly trying to optimize a speaker, only to have some neophyte come along and change its response through the flick of a switch, I might not feel very good. On the other hand, my well-designed speaker should sound better than a poorly designed one with Audyssey engaged.

I say it's whatever sounds good to you. Reality in audio is "your" reality as a listener. The more you listen, the more you start to understand which reality is best. Every time someone hears my M80s or my Audiobytes, they instantly know what they are missing with their systems. Some have purchased Axiom products as a result. Others couldn't for various reasons. Those same people that couldn't experience Axiom before, have been given the opportunity through AxiomAir. This is what I personally find very moving about this new platform.

My Audyssey did not screw things up in my room, it just made the overall sound slightly brighter which I suppose could be thought of 'cleaning up' the sound.

I really had to work at it to find a difference in the music material & only after repeating the Winwood interview numerous times that I concluded that the little bit more brightness was there but really not required IMO. My Axiom system seems to do quite well in my room without frequency EQ.

I still believe that Audyssey is fabulous technology that would have been nice to have 30 or 40 years ago when I started playing around with this stuff. There is no doubt that it can help smooth out some rooms that are difficult & I would not dismiss it as a viable tool...

TAM

What I found interesting (one thing of many) in the talk was the suggestion (which makes decent sense) that the "family of curves" will predict the in-room response with very high correlation for a very wide variety of listening venues when confining to the higher frequencies. The room modes, on the other hand, which dominate at lower frequencies, are highly variable and cannot be predicted except on a case-by-case basis. This adds some insight into Ian's comments that they would prefer to leave the higher frequencies pristine, out of the speaker.

Of course, one cannot really deal with room modes with an equalizer anyway (as Andrew has emphasized), since they are highly dependent upon location. A danger seems to be that one would try to "fix" an isolated local null that the microphone picks up, which is caused not by the speaker or by the sub but by the room. Then, the effect is corrected globally in the EQ, causing the opposite error at most local listening positions.

Dr. Toole's suggestion seems to be, moreover, that some of these very local interference effects are psycho-acoustically innocuous to human listeners, and that the cure can be worse than the disease. I suspect that this is a very real, correct, and practical concern. Especially at high frequency, any local interference effects will exist within a very confined region and making some room-wide compensation for artifacts picked up a one specific point would be absolutely the wrong thing to do.

Without a doubt, it seems that starting with speakers that have a flat frequency response and a smooth transition for the directivity (this is manifest by proxy in the gently / smoothly down-sloped sound power curve, if I understand) is essential. Additionally, the flatness of that curve should be maintained over a wide dynamic range, such that highly dynamic passages are not artificially subdued (compressed) in certain frequency ranges. This is what I interpret as "linearity" (increases in signal strength are manifest proportionally in output strength at "all" master volume levels and frequencies), and the point of the HP woofers. There are just some problems that start at the source, and cannot be corrected downstream. It would seem that quality speaker components and intelligent human engineers are not in danger of being made redundant any time soon.

On the other hand, there are certainly colorations that a room will induce, and to the extent that they are universal/global in origin (or can at least be sensibly averaged over), it also makes good sense that a carefully calibrated EQ could help out quite a bit. There is no shortage of user testimonial that the high end Audyssey filters (XT32 and Sub EQ for example) do quite substantially and very positively impact the delivered in-room experience. It should be emphasized that these systems sample quite a few points to get their suggestion for the global calibration, and are much less sensitive to local dips and interference coincidences than simpler approaches. I'm looking forward to playing around with it when my system is finally set up.

DSQ

We ran the first 'Iron Man' Blu Ray at -10 Db with Audyssey OFF.

This action movie with a very dynamic soundtrack sounded just fine without any EQ...

TAM

As many of you know, I have a pretty decent amount of acoustical treatments in my room. Every time I added more in the right areas, my sound became more crisp and clear (not in pitch, but in clarity). This included what seems to be a full range from highs down to LFE from the subs.

However, it wasn't until I turned ON Audyssey that things started to really shine, and in an even better way.

Dialog is much easier to hear (which was my main goal since my wife has a hard time hearing spoken words over the soundtrack and effects), and small details that were lost before we now able to be heard.

Maybe it is a different flavor and vintage of Audyssey (I have 3.5 year old MultEQ XT), but more than likely it is the room and our hearing of things in a room.

Even with EQ, some things just can't be fixed electronically, or some things are incorrectly interpreted by the processor (Audyssey in this case) and negative effects happen.

That is why they have an on/off switch for this stuff. TAM says that in his space, with his speakers, and his ears, that it gets to bright. In my space, with my speakers, and my ears, it sounds good and not bright, not painful, but with a bit more clarity and "impact." Who is right? We both are.

Having come from Pioneer Elite's MCACC to Audyssey MultEQ XT, I know that a NEED Audyssey in my next receiver too. Maybe it will even be XT32. Others may not find that value.

My Audyssey is the MultEQ XT as well.

I don't know if my Audyssey was making my room 'too bright' - it was brighter, but subtly. As I stated, in actual listening to music the difference was difficult to ascertain; however, speech recorded in a quiet studio was a little brighter.

Actually, either ON or OFF works just fine in my room...

TAM

That very much depends. I was able to clean up a huge 15db peak at 56Hz that appeared almost everywhere in my room. The suck out at 72 Hz was a lost cause.

I would agree on localized peaks and nulls though.

We watched The Hobbit 'Battle of the Five Armies' Blu Ray last evening at -15 Db with Audyssey OFF.

Sounded very good with nice clean dialogue & CC content from my VP160.

As for the movie, it was well done; however, I do tire of long continuous battle & fighting scenes similar to The Transformer series that drags out the carnage for far too long It's just too much sometimes...

TAM

Hi Fred -- This is an interesting / excellent observation. Let me elaborate.

All room modes (standing waves) will be intrinsically position dependent (they represent sine/cosine type spatial transitions -- or more complicated functions in oddly shaped rooms -- between pressure maxima at the room boundaries). Another way to say this is that energy conservation implies that a peak at one location must be compensated by a null elsewhere -- it can't be peaks everywhere in a zero-sum game. However, your counter example emphasizes a really critical feature: for very long wavelengths, the position dependence may be so broad (spanning across all of the listening positions in some cases) that it can really be interpreted as a global/constant effect for practical purposes, at least over the relevant confined listening area. The wavelength at 56 Hz ( note wavelength = speed of sound / frequency, where speed is ~ 343 m/s) is around 6 meters, close to twenty feet, so this caveat certainly applies.

The lowest room mode, taking parallel walls, will occur when the wall separation is half a wavelength. For a typical 20 foot dimension the lowest room mode would have a wavelength of 40 feet, or about 12 meters, which corresponds to a frequency in the ballpark of 30 Hz. In this case, there would be a null at the midpoint, with accentuation (an amplitude peak) at the boundaries. The second mode would be a full wavelength wall to wall with peaks at the boundaries (as always), but also at the dead center, in the interior listening area. The wavelength of 6 meters would correspond to a frequency right around the value you noted (say 56 Hz) and it would have positional minima (nulls) at the quarter wavelength locations, i.e. 5 feet from the front/back wall. As long as you were within, say, the inner 8 feet or so of the room, it would be pretty fair to call this a constant / global effect, as long as no one was seated close to the locations of the nulls. The third harmonic would correspond to the room dimension being 1.5 wavelengths, yielding a wavelength of 20 feet * 2/3, which is about 4 meters, corresponding to a frequency of about 85 Hz. Being an odd harmonic, there would be a null at the midpoint, which is prime listening real estate. It might just correspond to your experience (although there are effects from all three room dimensions that are more complex)

There is a nicely done writeup (which spared me from some trouble) here.

Cheers - DSQ

To add a (hopefully interesting) note, the comment of Andrew's that I was referring to is from last year in his excellent Sound and Vision interview on subwoofers here.



I wouldn't want to put words in his mouth, but it seems safe enough to extrapolate a bit. With multiple subs, placed at different locations, the way in which they excite the room modes, interact with the boundaries, and transmit sound to your location may be distinct. These two sources will interfere and tend to cancel each other's imperfections to some extent. The difficulty of the problem is that it does not exist just in the global frequency domain, but additionally varies locally from point to point. With two perfectly co-located subs, you will double the pressure output. The power is proportional to this quantity squared, so it goes up by a factor of 4. 10*Log_10 ( 4 ) = 6 dB. But, since the output of the two is spatially identical, the 6 dB boost is contributing to exactly the same peaks in exactly the same locations, and not improving the smoothness at all. If all that one wants is power, then doubling the number of subs will actually quadruple the power delivered at a location where peaks coalesce, at least for the selected frequencies. Of course, there is a price for this. Doubling the number of subs must, on average, precisely double the delivered power. This is not 6 dB, but 10*Log_10 ( 2 ) = 3 dB. You can't get 6 dB everywhere, it violates energy conservation, and the dynamic imbalance between peaks/nulls will be made worse at the spots where you do get it (for certain frequencies). If the subs are not co-located, then the interference may have the effect of spatial averaging, which would be a good thing for smoothness of response in various locations, limiting the artificial inflation or negation of frequencies that interact in particular ways with the room geometry.

Also relevant is the next Q/A:



Cheers - DSQ

Its fantastic to have you here DSQ. Excellent, well presented and informative posts. Cant wait to hear a little more about your space and maybe have you pick mine apart once I get rolling on setup.

Serenity -- very kind & glad to be here. I should put some pictures of my build up at some point. Its slow work, as I tend to go in little fits and bursts as time and energy allow. I've got a name picked out ... "The Limited Edition". I have a large collection of film (mostly StarWars and Rings) statues, and the current (now nearly concluding) phase of the build is shelving.

Look forward to some info on your build/setup as well, and happy to comment, but please don't mistake me for an expert on the more practical/applied aspects of listening room optimization (and certainly not on loudspeaker design). The underlying physics I generally do understand, but the application of those basic concepts to real environments is very specialized and requires experience more than anything else -- in that regard I am mostly a novice.

Cheers - DSQ