Identifying Legitimately High Fidelity Loudspeakers - Part 1

[3db]

Where did I ever claim that's all the NRC did?

My claim is simply that Canada set up substantial support network to nurture a Canadian loudspeaker industry, and thus represents a better example of state interference in the loudspeaker industry.

Are you arguing that I'm wrong?

Proove yourself right with facts and not personal opinions. Until then don't waste our time posting your BS rhetoric.

 

[gene]

Perhaps this site wishes to pursue a jingoistic (and defeatist) agenda. While I consider that sad and just a little pathetic, it is out of my hands..

Let's tone the rhetoric and accusations down a bit please. It's not my intent to blast the Chinese government hence why I am a co-author of these article series. There are many factors that both you and Paul brought out. This site has no motive against Chinese b/c Paul has strong opinions on the subject matter through his dealings.

You also seem pretty opinionated against horizontally mounted MTM speakers and I've learned overtime that there are no absolutes so let your ears decide if the speaker works well for your situation or not.

In any event, the next article digs a bit deeper into the myths surrounding speakers. I am sure there will be strong opinions on both sides. These articles are meant to stimulate conversations on these topics, not have people make unwarranted and false accusations that won't be tolerated on this forum. Thank you.

 

[DS-21]

It's not my intent to blast the Chinese government hence why I am a co-author of these article series.

Then why did you expressly single out China?

FWIW, I'm no Sinophile. Or Sinophobe. I just happen to have some academic and practical expertise in international political economy, and the claims made in this thread and in the article about China are misleading at best and bigoted at worst. And more to the point, they are entirely out of the scope of the stated topic, "Identifying Legitimately High Fidelity Loudspeakers."

IYou also seem pretty opinionated against horizontally mounted MTM speakers and I've learned overtime that there are no absolutes

I disagree.

Wide-open vertical directivity and constricted horizontal directivity is absolutely deleterious to high-fidelity music reproduction.

Off-axis performance that markedly differs from on-axis performance in the midrange due to improper drive-unit configuration on a baffle (i.e. a toppled MTM, but also other arrangements) is absolutely deleterious to high-fidelity music reproduction.

Directivity mismatches due to narrowing (mid)woofer directivity at the top of its passband and wide-open tweeter directivity at the bottom of its passband is absolutely deleterious to high-fidelity music reproduction.

Loudspeakers with 15 dB swings from 200-2kHz should absolutely not be even in the room when the topic is high-fidelity loudspeakers.

These articles are meant to stimulate conversations on these topics, not have people make unwarranted and false accusations that won't be tolerated on this forum. Thank you.

I assume with that you're putting Paul on notice.

 

[gene]

Then why did you expressly single out China?

FWIW, I'm no Sinophile. Or Sinophobe. I just happen to have some academic and practical expertise in international political economy, and the claims made in this thread and in the article about China are misleading at best and bigoted at worst. And more to the point, they are entirely out of the scope of the stated topic, "Identifying Legitimately High Fidelity Loudspeakers."

China was barely a focus of this article until you singled it out. This article has already been widely read in the industry. I have heard nothing but good comments from numerous manufacturers, all of whom manufacturer product in China! CEDIA and even Electronic House have picked this article up in syndication on their websites. Your opinion against the China points in this article are noted. Now let's move on.

I disagree.

Wide-open vertical directivity and constricted horizontal directivity is absolutely deleterious to high-fidelity music reproduction.

Off-axis performance that markedly differs from on-axis performance in the midrange due to improper drive-unit configuration on a baffle (i.e. a toppled MTM, but also other arrangements) is absolutely deleterious to high-fidelity music reproduction.

Directivity mismatches due to narrowing (mid)woofer directivity at the top of its passband and wide-open tweeter directivity at the bottom of its passband is absolutely deleterious to high-fidelity music reproduction.

Loudspeakers with 15 dB swings from 200-2kHz should absolutely not be even in the room when the topic is high-fidelity loudspeakers.

Agreed but as you can see in the measurements, the MTM I measured didn't exhibit such behavior when measured 27 deg off axis (more like 5dB dip from 1k-5kHz but actually looked flatter when compared to the entire frequency spectrum).

Also note my comments below about the measurement:
At this measurement position the MTM measures very similarly whether oriented horizontally or vertically with the exception of a 5 dB boost centered around 2 kHz in vertical orientation. Arguably the MTM measured more linearly at the primary listening position when horizontally placed. As we indicated earlier, the reduced output of the off-axis MTM is actually beneficial when the listener is placed near a sidewall. The two-way again measured nearly identical to the vertically mounted MTM. Hence even sitting near a sidewall we see the MTM does a good job whether placed horizontally or vertically. It’s important to note that this is a very well executed MTM design and your mileage may vary depending on how well the manufacturer executed the crossover and chose the correct drivers to match the system.

All speakers exhibit lobing to some degree even W(T/W)W designs. MTMs tend to be worse, but well executed designs still have merit as center channels, especially if the listening seats are under 30 deg off axis, which most are in home theaters!

I invite you to read the conclusion of my article that provides some practical and useful guidelines on the topic.

Below are some useful guidelines to consider when choosing a center channel speaker:

Choose a center channel that has similar output capabilities and sensitivity as your main channels.
It’s usually a good idea to choose a speaker from the manufacturers same product line of your main channels to ensure similar drivers and tonal characteristics “voicing”.
Consider a horizontally mounted MTM design if you have a height restriction and your primary seats are in a +/- 30 degree listening window or less.
Consider 3 matching vertical MTM designs for the front 3 speakers if you can place the center channel behind a perforated screen.
Consider W(T/M)W design if your listening window exceeds the +/- 30 degree and you are height constrained to not use identically matched speakers to your mains.
Bottom line, chose what sounds best for your application that tonally matches your main speakers as closely as possible.
Don’t forget to calibrate all of the channels using the internal pink noise generator (aka. Test tones) of your A/V receiver / processor.

MTM and W(T/M)W are the two basic center channels designs that are most popular. There are many variants of each all with their associated strengths and weaknesses. The best advice one could give when choosing a center channel speaker or any of the speakers in your theater room is to NOT just blindly rule out a particular type of design because someone says it theoretically cannot work. Test them with your ears in your listening environment across your listening area to decide if they are right for you.

I assume with that you're putting Paul on notice.

No actually but consider yourself on notice. MOVE ON!

 

[randyb]

I must be too old. I thought Japan was the reason we lost our manufacturing base. I guess some younger people don't remember "Made in Japan" was a joke about quality and then suddenly, everyone was buying made in Japan. Seems the same to me as before.

 

[gene]

A Final Note About China

I just would like to say, I don't blame China for anything. I blame Corporate America and its power over our Government for always looking for a way to save a buck even if it means screwing its own citizens. There was a time when "made in USA" wasn't just a slogan, it was a reality. Sadly, I don't believe we will ever see that again.

 

[cschang]

Great article and interesting thread.

 

[MinusTheBear]

I'm really looking forward to the remaining two articles now.

Can we get any spoilers on the loudspeaker myths that will be discussed in the next one? Just the topics will suffice.

 

[GranteedEV]

I've done listening experiments comparing good MTMs to not so good W(t/w)W designs and preferred the better engineered MTM. The whole issue is a bit overstated in my opinion. Most people don't sit that far off axis and a good MTM can produce a very dynamic sound compared to having a little 4" driver of a W(t/w)W doing most of the vocals.

I think that's a matter of execution. On paper, a 3-way with a pair of 6.5 inch woofers crossed to a 4 inch woofers, should have better power handling than a pair of, for example, 5.25 inch drivers.

The crossover is the heart of the speaker. An MTM is always going to be inherently flawed as a center channel but a good crossover can of course salvage it somewhat, but a good crossover and quality drivers for a WTMW, should produce better results and It really doesn't make sense to me why companies continue to make MTM centers.

You can make an acceptable sounding MTM center speaker, by crossing over to the tweeter very low (close to 1khz hopefully). But then you've still run into a problem of power handling just like those poorly designed WTMWs you've heard. Unless it's like a 2" tweeter; that could work if it's clean enough. So you raise the crossover frequency. Now you've got a quickly narrowing off axis response, until the tweeter comes in and does the opposite, widens the off axis response. The power response of the speaker in the room, is flawed.

I'm sure it's possible to find a balance between the two where they don't sound unlistenable. But why bother?

There's definitely some smaller mids that can handle power and have adequate sensitivity. They maybe can't do bass, but that's why it's a WTMW, not a TM. Accuton, B&W, ATC, Visaton, Scanspeak, and Harman have some small drivers that can handle as much power or more as larger drivers in the right system. Recently, Kevin Haskins was working on a low inductance 5.25" midrange driver with about 8mm of rated xmax, 6mm of that completely linear on the BL/CMS curves.. somehow I think that wouldn't be dynamically limited as the mid in a 3-way ;P

And of course, there's coaxial drivers too, which take up the same vertical space as a "TM" with a smaller woofer, but use a larger driver. Pioneer and KEF have some center ch offerings in this regard.

At the end of the day, if you want a well engineered speaker, there's a lot of factors at play, that we both agree. But I wouldn't say the use of 4" drivers as mids is inherently flawed in a 3-way speaker (that tends to effectively become a 4-way when a sub is introduced)

This PMC speaker for example, uses just a 3" dome midrange. That doesn't mean it's necessarily dynamically limited, unless we're talking about the size/distance of rooms where compression drivers are necessary.

 

[GranteedEV]

Agreed but as you can see in the measurements, the MTM I measured didn't exhibit such behavior when measured 27 deg off axis

In an acoustically dead room, where side wall reflections are completely absorbed, this might not be a problem.

But in an average room, or an acoustically live treated room, what kind of reflections are you getting from that MTM?

27 degrees is NOT the second reflection or even first reflection, horizontally.

Measurements out to 60, maybe 70 degrees are necessary to determine how a speaker behaves in a room. I'm still waiting for AH to start measuring polars out to 60 degrees. "Subjective Stereophile" measures out to 90 degrees and even 15 degrees vertically ;P

You pointed out that the lack of side wall reflections in the midrange might be a desir-able trait, but the tweeter is still reflecting off the side wall like crazy.

The only way an "MTM" center would work and still be balanced sounding, is if it looks like a mini-version of this:

Then you can say the side wall reflections are inoffensive, because there's an effort to focus on the power response out to 60+ degrees, by guiding the waves on the tweeter to follow closely to the wave behavior of the woofers,, which are tilted out a little bit. There will still be a narrowing of directivity as they go from omni to monopolar, but no switch BACK to near-omni at the crossover point.

It's still not as optimal in terms of consistent off axis response as an acoustically small dipole like three Nao Notes but at least there's an effort to control what's going on, rather than just living with a very narrow directivity accompanied by tweeter bloom. You really want smooth sound power response, not just adequate listening window response which is what 30 degrees would encompass.

"Living with it", to me, sounds like a cost-cutting maneuvre, which returns us right back to the article. MTM centres are an easy cost compromise to make but while I don't agree with DS-21 on a lot of things he said, this is one point where he's correct in that a (high end) speaker would not use an MTM center speaker.

Even the W|TWTWT|W on the RBH center you use, makes a lot more sense, or at least I would hope with the right crossover(where the inner woofers play higher but the outer woofers come in later) but without 60 degree polars and without having heard it, I can't say anything about it.

 

[mtrycrafts]

... Most people don't know good sound, let alone the benefits of multi channel music.

I have been meaning to post a message in this thread since it pertains to this, would it be possible to list speakers that you and Paul, perhaps, consider worthwhile speakers to listen to for good sounds? Perhaps companies that do a good job of design, attention to details mentioned in this article.

If I ever need speakers, I am not about to take them apart and try to compare to these articles.

 

[3db]

I just would like to say, I don't blame China for anything. I blame Corporate America and its power over our Government for always looking for a way to save a buck even if it means screwing its own citizens. There was a time when "made in USA" wasn't just a slogan, it was a reality. Sadly, I don't believe we will ever see that again.

Thats exactly it Gene. The only people who benefit from outsourcing are the corporate execs with their performance bonuses and outlandish salaries while the middle class in both the US and Canada is shrinking. The US was born to escape a class based society but corporate America thru nothing but their own greed is bringing back the classes.

 

[gene]

In an acoustically dead room, where side wall reflections are completely absorbed, this might not be a problem.

But in an average room, or an acoustically live treated room, what kind of reflections are you getting from that MTM?

27 degrees is NOT the second reflection or even first reflection, horizontally.

You got it backwards. Ill effects of lobing are more prevalent in an anechoic environment since sidewall reflects won't be present and thus influence the measurement.

I think that's a matter of execution. On paper, a 3-way with a pair of 6.5 inch woofers crossed to a 4 inch woofers, should have better power handling than a pair of, for example, 5.25 inch drivers.

I would not compare a 3 way center to a MTM using 5.25" woofers. The good MTMs capable of more dynamic range utilize 6.5" woofers.

Coaxial drivers that you refer to have their own host of problems which is why most truly high performance, high dynamic designs don't use them.

 

[GranteedEV]

Coaxial drivers that you refer to have their own host of problems which is why most truly high performance, high dynamic designs don't use them.

Most? If "most" use MTM designs, then I wouldn't call then "TRULY high performance".

FWIW, I can name four speakers

Genelec 8260A
TAD Reference One or Pioneer S-1EX
KEF Blade or 207/2
Seaton Catalyst

Which I suspect don't significantly suffer from any of the issues you allude to.

You got it backwards. Ill effects of lobing are more prevalent in an anechoic environment since sidewall reflects won't be present and thus influence the measurement.

Maybe I'm thinking of this wrong, AFAIK, if you sit on axis, the MTM drivers should be in phase (not lobe, minus maybe from the crossover to the tweeter)

The major lobing is off axis and pretty consistent to the point of creating a power response suckout.

What you're thinking of, is where a smooth power response might "fill in" a flawed listening window response. But in a reflective room, it'll do the opposite because an MTM will not have a smooth power response (whether that's vertical or horizontal) - instead it'll "fill in" above and below the lobing region for an imbalanced timbral presentation.

I would not compare a 3 way center to a MTM using 5.25" woofers. The good MTMs capable of more dynamic range utilize 6.5" woofers.

Likewise, maybe you should not (dynamically) compare a higher power handling MTM to a 3-way center using 4" midranges(although I contend with good drivers, and smart crossover it can still work very dynamically). The good WTMWs capable of more dynamic range would utilize midranges flanked by either 6.5 or even 8 inch woofers and crossed over to optimize power handling, like this:

http://www.troelsgravesen.dk/8008CENTER.htm

Heck, the Seaton Catalyst I mentioned up there, uses an 8" coaxial with a pair of sealed 12" woofers

I think at the end of the day, all speakers calling themselves truly high end, need flat listening window response and smooth, controlled power response. By design, MTMs have more than just narrow Q crossover suckouts. So they're not optimized for smooth sound power response. Now placed vertically, they can still sound great because of the way our ears hear horizontal reflections more dominantly than vertical (and that a good listening room would invariably address vertical reflections as being problematic and treat them for 99% of speakers minus the coaxials above)

Now if you don't subscribe to the importance of smooth sound power response at all, then I guess it is what it is. If only listening window response needs to be measured to determine what a person will hear from a speaker, then just get me a parametric EQ and anything measuring flat in that region should suffice.

 

[gene]

The crossover is the heart of the speaker. An MTM is always going to be inherently flawed as a center channel but a good crossover can of course salvage it somewhat, but a good crossover and quality drivers for a WTMW, should produce better results and It really doesn't make sense to me why companies continue to make MTM centers.

You can make an acceptable sounding MTM center speaker, by crossing over to the tweeter very low (close to 1khz hopefully). But then you've still run into a problem of power handling just like those poorly designed WTMWs you've heard. Unless it's like a 2" tweeter; that could work if it's clean enough. So you raise the crossover frequency. Now you've got a quickly narrowing off axis response, until the tweeter comes in and does the opposite, widens the off axis response. The power response of the speaker in the room, is flawed.

I wonder how much design experience you have with loudspeakers to make such blanket statements? I've actually consulted with many loudspeaker engineers including Dr. Toole on this very subject. Companies continue to make MTM's b/c they can sound quite good if properly designed. A very robust 1" tweeter such as a Scan Speak 9500 has massive power handling, but the driver is expensive and no mass market companies would use such a beast in their loudspeakers. You can improve MTM lobing by placing the Tweeter higher up and bringing the woofers closer together as some do but its not a night/day difference. I still prefer a truncated line array to virtually anything else b/c it gives lifelike dynamics with most of the benefits of a true line array but with a more focused soundstage. However even those have limitations. All designs are compromises any way you look at it.

Coaxial drivers are the closest thing to a point source, but they have trade offs (increased doppler distortion, more thermal compression, etc) and I'm not sure a point source is really ideal for setting up a truly dynamic and lifelike soundstage in a real room. How a speaker plays into a room at high SPL levels is something that you rarely see anyone measure and virtually no manufacturer will show this b/c it reveals flaws in their designs.

 

[GranteedEV]

Companies continue to make MTM's b/c they can sound quite good if properly designed.

Good enough that you would toe them in and use them for stereo listening horizontally?

All designs are compromises any way you look at it.

And MTM center speakers, are a huge one I see no pros to, compared to a well designed WTMW or WCW. Whether it can sound decent or not, I don't understand why someone would start with a bottleneck like this. The only advantage of an MTM I see, is reduced complexity and reduced cost. But then, one could say the same about a one-cap, one-inductor crossover. That "it :can: sound good". I don't doubt it, but I don't see why someone would make the choice.

Coaxial drivers are the closest thing to a point source, but they have trade offs and I'm not sure a point source is really ideal for setting up a truly dynamic and lifelike soundstage in a real room.

The biggest advantage of a coaxial isn't just to be a point source, but its ability to act as a waveguide for the tweeter.

The seaton catalyst is going to be extremely dynamic (maybe more than your triple-SS9500 mains). How does it sound? I can't tell you how a speaker I haven't heard sounds. But at least the Listening window response, power response, and power handling appear to be extremely good. Beyond that, if you prefer what you prefer, that's your prerogative. But if it has a mess of a power response then it's not going to be something you should be calling "TRULY" high end.

I don't know how loud the TAD or KEFs can play, but genelec does give this data on the 8260A:

SPL
Maximum short time sine wave acoustic output at 1 m on axis in half space, averaged from 100 Hz to 3 kHz	≥113 dB SPL
Maximum peak acoustic output per pair with music material	≥123 dB SPL @ 1m

I doubt it's nearly as dynamic as the Catalysts, but that was just a response to what you were saying about manufacturers not giving any power compression data.

Regarding doppler distortion, that's a function of excursion. This brings us back to the crossover. A 3-way speaker would cross the midrange high enough, that it's barely moving even at high power levels; not enough to make audible problems.

As for thermal compression, I do wonder how much power might be located above 400hz, compared to a pair of woofers handling below that range. Add in the fact that a truly high performance speaker has drivers optimized to handle extreme power (the catalyst midrange is fed about 700 "ice power" watts) so I don't see the issue.

Again this brings us to the catalyst. An 8 inch "pro sound" type custom coaxial, crossed over something like 300hz. That coax is designed to take a beating. It brings us right back to what the article was about - high sensitivity, high power handling type drivers.

Maybe I mistook this article for talking about high end speakers, when it was moreso about acceptinbg budget compromises. That's what I see an MTM as.

 

[GO-NAD!]

Regarding the horizontal centre channel speaker, nobody has addressed the reason for its existence in the first place. It didn't pop out of thin air. It came about, so that it could be placed above, or below, a television display. I don't have statistics, but I would guess that the overwhelming majority of centre channels are placed this way. It's most certainly a compromise, but how does one work around that? People have to actually place these speakers in their systems and a typical setup does not easily accomodate a vertical centre speaker.

One can argue until he's blue in the face that there is no place for a horizontal centre channel speaker in a properly designed multi-channel system. But, multi-channel systems do not exist in a vacuum - they have to be integrated with the room and its other contents. Very few homes have projectors with acoustically transparent screens. So, until all displays can be made AT, we are stuck with horizontal centres. Arguing against them is an academic exercise and is simply tilting at windmills.

Grant, if you can come up with a vertical centre that can be as easy to physically integrate into a typical HT setup, as a horizontal version, you could make a fortune.

Even though I have an AT screen, it wasn't always so - which is why I still have my horizontal centre. Will I ever change it out for a vertical centre? Maybe, but I'm in no hurry.

 

[MinusTheBear]

Well engineered "High End" includes but is not entirely synonymous with Identifying Legitimately High Fidelity Loudspeakers . I am under the impression some have made that confusion that "high end" is only high fidelity.

 

[3db]

Well engineered "High End" includes but is not entirely synonymous with Identifying Legitimately High Fidelity Loudspeakers . I am under the impression some have made that confusion that "high end" is only high fidelity.

You said a mouthful. Check out Audioasylum or Steve Hofman's forum ... in their mind mega$$$ is always high fidelity.

 

[GranteedEV]

Don't get me wrong, I think a horizontal center is A-OK.

But we should still hold them to the same measurable standards you'd hold main speakers (smooth horizontal polar response out to 60 degrees especially from the shroeder frequency up to around 8khz), flat frequency response, low IMD/THD/cone breakup/horn honk at high drive levels, low cabinet resonance, proper relative phase on axis between drivers, etc)

http://p.gzhls.at/185609.jpg
http://media.gdgt.com/img/product/32/p7f/verus-grand-center-channel-2lq6-460.jpg
http://www.hometheater.com/images/revel2.jpg?1282071720
http://ww1.prweb.com/prfiles/2011/01/31/1346384/AperionVerusForteCenterBlack.jpg
http://www.seaton-sound-forum.com/file?id=1032624


Heck, how about this CBT line array center channel?

http://www.avsforum.com/avs-vb/attachment.php?attachmentid=162694&d=1262686480

The frequency response, at 70 degrees off axis, does not have a 20db relative null in the midrange:

http://www.avsforum.com/avs-vb/attachment.php?attachmentid=162690&d=1262683339

Compare the above, to a typical horizontal MTM,. and note specifically the tweeter's wide directivity coming into play:

But if Dr. Floyd Toole says that MTM centers are A-OK too, then who am I to argue with him? But then, Harman only has a few speakers I can think of, which ostensibly could be called an MTM, and all of them are bottom-of-the-line budget offerings.

When you get to a level up from that, you've got the Revel C12:

and JBL LC2

As soon as you get even one level up, Harman no longer uses MTM center speakers. So I contend that, a horizontal MTM center, is a budget constrained choice, and not indicative of something we're going to call :truly: high fidelity.

If we're going to open up speakers and complain about stamped baskets and electrolytic caps, I don't think i'm wrong when I say that polar response is a lot more significant in what we hear than a stamped basket.