Axiom Home Page Forums General Discussion The Water Cooler Comb Filtering - AVS Thread

I cringe to think where this is going to go:

http://www.avsforum.com/forum/89-speakers/1903601-how-i-learned-stop-worrying-love-comb.html

Lots of reference to Axiom in there...

TAM

I am sure, before too long, the same cast of characters will emerge from the woodwork. It is interesting to note, whether it is this kind of stuff or something else, I learned a lesson long ago from a neighbor of mine who essentially stated, "if you can't hear it or see it, it really doesn't exist". The reason I put some stock in that comment is that this fellow was a broadcast technician for a television station, a computer expert, an A/V enthusiast who had an extensive set-up and a fellow who had actually built his own video processors that he had integrated in to his rack. He also had an extensive line-up of various testing equipment in his home which in addition to testing the performance of equipment, it also could test various audio and video cables as well. Periodically, we would test various pieces of equipment and cables and, at times, on that test equipment, variances in "alleged" performance would register, yet, when doing critical "real world" viewing or listening, rarely, if at all, could either of us detect any differences.

I guess the bottom line is, while reviewers and naysayers of various brands use this kind of information in graphs and test equipment to justify their positions, for someone to make a decision on how good a product is using these methods is, at best, "questionable".

I went back & read the whole thing & I think that my head is about to explode, ha!!

My beliefs all along have been that in most HT rooms, this stuff just is not a significant factor.

For those who care not to indulge in AVS, this is my 'layman's' reply there:


In my unscientific experiments with 4 horizontal CC Speakers of different brands only using my ears, I found that in my room, unless one is placed so far off center (+30 degrees), audio deficits were basically not audible to me.

Furthermore, if one is sitting at beyond 30 degrees at 11 ft from my screen, far more serious visual problems with the display begin to crop up & are much more distracting & degrade the HT experience. Not the place to be IMO...


The advent of laptops couple with software & cheap microphones has many people thinking that they are portable anechoic chambers. Sorry, but they aren't - although they can be an interesting tool I suppose.

I now just enjoy the material & don't sweat the small stuff that many enthusiasts needlessly obsess over...

TAM

Hats off to the Doc. A very well presented intro to a discussion of a topic as cryptic to understand as it is to realise in an actual room. With pink noise it can be observed readily, but it is very hard with program material.

I think posts like this are of high value, not only for Axiom, but for those who wish to understand the behavior of audio and relate theory to improvements into their rooms. I look forward to DrStrangequark's conclusions after setup.

Honestly, the one person who could spot it reliably it seemed was Mojo. He had issues in his setup and could find the same issue in mine. He had developed an ear for it I guess. I had never noticed it before..... There are so many factors apart from the speaker design itself that I would argue contribute more to the overall sound experience.

There is a lot of nonsense sabre rattling over at AVS. I picture a group of the same 5 guys together with sore hands from repeated top gun high fives. However, AVS isn't universally terrible. Some people just spend waaay too much time there instead of with real human interaction. Their online life simply becomes their life. Kinda sad.

Sitting in my 'sweet spot' running test noise material from my Denon AVR, I can hear the difference between my L & R M22s & my VP 160 Speaker - even though they are supposedly timbre matched. It is probably because I'm off axis with the L & R whereas I'm right in the center of the CC.

Is this apparent during real world material? Not that I can tell & I certainly don't fret about it.

Doc was logged in here today & I had a couple of interesting PMs with him. Very reasonable guy...

TAM

I suspect most room correction software can take care of it smartly anyway unless your a purist and listen to 2 channel direct or dsd.

I may as well comment since i am also a scientist who holds a PhD....which sometimes for some people means "pretty horribly dumb" since often some forget to look at the big picture and get too focused on the minutia...

Sure, there are things that can be measured, but the question remains as to whether they can be heard and interpreted by the human ear/brain.
Although the AVS post is well thought out, the very remark made near the start in paragraph 6 " I am not a golden-eared audiophile, although I know good sound when I hear it" says to me that this scientist hasn't done basic research in pychoacoustics regarding the published material and the fact that the concept of golden eared people is a fallacy (no personal offence intended, maybe he is aware).

Bottom line, as said by those previously, even though it can be theorized or measured, does it matter?
Can humans even hear it under controlled conditions?
If not, who the hell cares?

Luke Skywalker.

God save us all! A self-aware Ph.D!

I sense the docs midichlorian count is high. We should follow his path closely. Search your feelings Chess, you know this to be true. The fate of the rebellion may depend on it....

::wipe to rebel fleet::

At a meta level, I have to question why people are so vehement about Axioms and seem to constantly use them as an example. After all, if they believe them to be no good, why mention them at all? Are they really so popular they have to be brought up as a counter example all the time a la Bose?

Or maybe we're just loud and annoying.

People fear what they dont understand. The Axiom designs are different and inherently evil, of course. If you dig a little into who some of these guys are, and check their room pics for example, you will see they have no place being in a conversation where high quality audio is at question. They all parrot what they read online.

Reading about skinning a deer is not the same as skinning a deer. Oh, dear!

I guarantee if you saw my room, you would say the same thing about me...

Perhaps, but these guys are the ones shouting from the tops of Ivory towers. Besides, it is my conclusion that ANY Axiom owner, regardless of setup limitations, has arrived at their choice from researching options and valuing the research effort behind the products. That says something. Axiom attracts a certain calibre clientele. The lucid kind.

TAM -- At the moment, nowhere, it would seem! That's fine too. I don't really enjoy kicking hornet's nests, but am not a big fan of bullies either.

Enjoyed our PM's. I usually tend to read the forums substantially more than post. And since I haven't been actively considering substantial electronics/speakers purchases over the past several years (before about one year ago), I wasn't even really doing much of that.

The bottom line is that my family (following recommendations on my part for my Dad's theater) has been thrilled by the performance of a modest Axiom setup (including the sometimes maligned VP150 center channel!) for over a decade, and I thus always imagined starting there when it was time for my own dedicated theater build (i.e. now). But, some of the criticism elsewhere that has built up in the last few years struck me as out of proportion, personal, mean, incomplete or misleading, poorly justified, and in many cases either no longer applicable to upgrades in the current line, or completely incorrect. This offended me at some deep level, and I wanted to really gather my thoughts, do some calculations, assemble additional facts, and present my conclusions in a (hopefully) coherent way.

I sincerely hope that it turns out to be helpful and constructive rather than counter-productive. We'll see.

Cheers -
DSQ

There are just a handful of people that jump at any opportunity t bash Axiom. Some people used the forums elsewhere to grind that axe and do it in a way that is convincing to many people that have zero experience with Axiom, and thus it spreads. I think that between a couple of us here we can name several of the people that we know will show up in your thread at AVS as soon as they find out about it. I don't want to name them because it just boosts their ego and then they look at it as they are "winning." Winning at being a tool maybe, but they don't see it that way and it just encourages them.

Hi Chess -- I've always heard "Piled Higher & Deeper".


You might be reading a bit over-literally there. If there had been scare-quotes around "golden eared" it might have scanned a bit closer to my meaning. Nevertheless, the implied confession that their are many members here and at AVS with a substantially more refined level of critical listening experience is sincere. I'm aware of the principle, for example, that listeners somewhat universally (regardless of experience) prefer flatter frequency response curves. Nevertheless, it is certainly true that some training in critical listening can allow an individual to better differentiate and identify sound reproduction characteristics that may be challenging to realize from an engineering perspective (the sharpness of percussive attack, for example). You are anyway correct that I have no special expertise in psycho-acoustics (beyond a very minimal quantity of reading). I'm guessing that maybe you do have direct research experience in this field? Sounds Cool.

Cheers-
DSQ

Serenity - much appreciated. I am looking forward to experiencing & reporting on my theater as well! However, I'm somewhat dreading a few of the DIY hurdles that must be overcome between here and there first!

DSQ, welcome and thanks. For my money, nickbuol's threads here on Theatre construction are reference quality material. Enjoy your journey.

I'm blushing, then again, my threads and insights are free, so "for your money" that might not be very good.

DSQ - welcome aboard!

The lack of further response is not surprising because I've noticed that posting seems increase during week days when most people are at work, ha! So wait for it!

This is the second instance in the last while at AVS where factual posts concerning Axiom like this one (instead of childish hearsay, parroted third hand info & often misguided opinion) have stopped the thread in its tracks. My best rebuttal is to direct posters to the excellent & objective reviews of Axiom (and other brands) at the highly credible HTS site. Comments then normally stop.

Because of my observations lately, I can only conclude that 'Brains' baffle 'Bullshit' instead of normally the other way around...

TAM

I doubt that thread will get a whole lot of attention at AVS these days but it would if you took it to Audioholics. The usual naysayers seem to be absent of late.

Let's hope so...

TAM

Only 5 posts on the AVS forum ? That seems hard to believe

Before buying a VP180 I doodled up some (much less sophisticated than the Doctor's) calculations for comb filtering on each of the driver pairs and was actually pretty impressed with the results.

That said, I lived with a VP100 for several years (pretty much your common or garden D'Appolito array) and only heard audible comb filtering on a single track -- I forget which one, but it was a single-note-guitar-heavy track off Genesis' Nursery Cryme and was only clearly audible when I picked a stereo-to-5-channel matrixing option that pumped up the center channel volume.

Playing the same track with a VP180 resulted in less comb filtering effect, although since I can't remember which track it was I guess I have to go dig the CD out of my carousel and play it again upstairs on the HT system...

Still carrying the torch, I see.

Anti-science sentiment in modern society is frightening.

Well, here again and as I mentioned earlier, it is the same small cast of characters involved anyway(as many of us know, one in particular who use to comment in this forum). In his case, when people questioned his ideas, I guess he got his feelings hurt and doesn't comment anymore, whereby, it is now, for no other reason just a case of regular criticism whenever the opportunity arises and AVS and to a little lesser extent, Audioholics are his forums of choice. In this manner, I believe it makes the deal seem a lot bigger than what it really is, especially when it come to Audioholics "infamous" history.

I am heading to Axiom tomorrow and I will look for those combs and filters and make sure that they are behaving.

Hopefully we don't get much snow. I hear that the drive from Toronto is long enough on clear roads.

And I thought that speakers were more of a subjective thing, much like music itself. You find what you like and though it may be different from everyone else, it's right for you.

I'm not sure if this is comb filtering, but I ran a test once with the on-wall M22 (mounted on the wall) vs the Bookshelf M22 (mounted on the stands designed for them). I had a sound abnormality with the on-wall, but not with the bookshelf.

I played a constant frequency at a constant volume level, using a CD designed for testing and adjusting your speakers.

Then using a Radio Shack sound pressure level meter, at a distance of 10 feet from the speakers (and pointed toward the wall with the speakers, without any rotation of the meter), I slowly walked from one side of the room to the other side, while watching the meter.

With the on-walls, the digital display would show different volume levels every inch or so, sometimes, by quite a lot.

With the bookshelf speakers, the volume was at a constant level as I walked.

Not sure what that proves. But, by just listening at normal source material, I couldn't notice anything that was off.

I'm attributing this abnormality to having speakers mounted on the wall, and not to any defect in Axiom speakers. Similar speakers from other manufacturers should show the same thing.

NICK! Have a great time!

Matt, research used by Axiom and others has established that "most people" prefer speakers that have a relatively neutral (flat) frequency response.

AND I'm definitely not a scientist. Graphs are boring, I'm in it for the fun, and "fun" comes from all kinds of sources.

I looked for combs and filters, and didn't see any causing problems.

Ian and I did chat a bit about comb filtering, and he said something that I never thought of...

If you have a 2-speaker stereo setup for listening to anything, then those 2 stereo speakers are creating comb filtering. The only way to eliminate comb filtering in that situation is to go to a single mono speaker, and who wants to listen to anything in mono?

Just by going from mono to stereo creates comb filtering just like what happens when center channel speakers have more than 1 tweeter in the same plane.

Audiophiles don't complain about comb filtering with their stereo setups, and blind testing (per Ian) proves that people LIKE and PREFER the comb filtering stereo setup over a mono speaker.

Imagine the comb filtering going on inside a car with the tweeters facing up toward the windshield. It is a great topic for controversy , just don't take it personal.

DrStrangeQuark, any progress in your setup you want to share?

I'm bald, so I guess it's nothing that I have to worry about

Random thoughts ...

1. Ian needs to stop with logic and reason. That confuses people.
2. It's too bad Axiom doesn't make a center channel with either the standard MTM design in the $300 range or a vertically mounted midrange / tweeter in the $700 range.
3. Does anyone still go to AVS?

I go in there several times per day just to keep an eye on things. I post only when absolutely required & even then, I tread very softly. I am happy to report that things have quieted down dramatically (re Axiom) in the past year & hopefully it will stay that way.

I was able to snag a new VP160 from the deals section for $320 last year. I've been more than happy with it - accurate, powerful & clear. No comb filtering within our normal listening area that I can ascertain.

As I've pointed out in several threads over at AVS based on my listening, this is a condition that I believe is highly overblown & exaggerated & is not a significant factor in most Home Theaters. I suspect that horizontal CC Speakers generally work just fine in most setups...

TAM

Tam - That was my personal sarcasm on the "science" of that place. It's always amusing how people will slam a product without hearing it.

I have a 10 year old 150 here, and it still functions great.

For a brief history, from 2010 until 2014, I was "in the industry" as a home theater company with my brother as a partner - and did on line reviews from 2001 until 2010.

The review side will be starting again this year, and Ian was the first manufacturer to respond in a positive manner when I wrote him.

While this won't get him any special treatment in reviews (nor would he ever ask for this), it does warrant mention and appreciation.

The old review process I did was unusual - I would buy the products, review them, then sell them, with critical listening being done blind.

It's a lot of fun, and the process will be public on Home Theater Shack - look for a much nicer experience there.

Hi Craig. Good to see you popping up around here again. Looking forward to the reviews and to hearing the M1s.

I really liked your sub ranking list. Welcome back to Axiom. Many of us here share dual citizenship between Axiom/HTS and some also at AVS. I used to partake in AVS fun, until I realised it wasnt so fun there afterall. Waaaay to serious and catty. So many EXTREMELY helpful posters there. But great content and news reporting. Love their podcasts.

Again welcome back.

HTS is definitely a cut above the other 2 big audio web sites out there IMO.

I visit HTS daily as well, but having a more mature & less argumentative membership there, I don't have the requirement to post as often. Thankfully, every manufacturer seems to get a fair shake & HTS doesn't put up with the BS that others out there do.

Looking forward to your new endeavours there...

TAM

You know, your regular posts concerning non Axiom defense issues are great too, right? . You're supposed to be retired from defense duty.

I don't know if they are all great - some I would like to have taken back, ha!; however, as craig says, using the same logic & reason here & at HTS doesn't always go over well elsewhere.

Even though I'm retired from defense duties, I will continue to do my 'dawn patrols' while I'm partaking in my morning coffee...

TAM

Tam - Because you provided a link to your thread, I went to that forum for the first time in about 18 months, give or take.

The reason it has been so civil boils down to these two reasons:

1. "PHD in Physics"
2. The usual crowd had no idea what the "bleep" you posted. I guarantee you a bunch of guys are salivating and hoping that "one of their smart guys" might be able to discredit you. They will have a long wait.

Looking forward to reading your thoughts on the speakers when they arrive, and your thread title was sheer genius!

Just for clarity's sake, the wonderful post over there re Comb Filtering was penned by DrStrangeQuark, not me. I'm not that smart, ha!

TAM