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Current Trends in multi thousand dollar speakers

Have any of you been paying attention to the current trends in larger multi-woofer speakers that cost multiple thousands of dollars? So that many of you can follow along, i'll use the Legacy Focus 20/20's at $6K, the Piega C8's at $15K and the Aerial 20T's at $23K as points of reference. All of these have been reviewed in Stereophile over the last few months. If you're not familiar with these, all of them are vertical dynamic designs using multiple woofers in vented cabinets.

If you look at the response of of these speakers, they all have very pronounced bass peaks with elevated low frequency plateau's taking place. Of these three, the Legacy's are by far the worst of the bunch. Not only do they diverge from neutrality the most ( +7 dB peak @ 100 Hz ), their elevated bass output or "low frequency plateau" levels out at 40 Hz and at 400 Hz. That is over 3+ octaves of "extra" output that wasn't on the recording. Above 400 Hz, the output levels off with very noticeable rippling slightly above that point in the midrange and multiple large peaks with a dip up in the treble response. Below 40 Hz, the output drops like a rock. The reason that the plateau levels out at 40 Hz is because of the associated sharp roll-off associated with vents below their point of resonance.

To sum things up, this speaker, which Paul Bolin raved about in Stereophile, is anything but "smooth" or "linear" in reproduction. As can be seen in the graphs, there is a very definite "boom & sizzle" type of response taking place here. As a side note, i found that the Legacy Signature III's showed a similar large bass peak centered at appr 100 - 110 Hz, so this would seem to be a consistent design attribute / "house sound" / "family voice" to Legacy speakers.

Moving onto the Piega's, their overall response looks to be measurably smoother than the Legacy's from the midrange on up. As far as bass goes, the Piega's peak occurs at an amplitude of +5 dB's and is centered at appr 85 Hz. Their "bass plateau" is quite wide, actually just as wide as that of the Legacy. Both show the same appr "elevated output" aka "bloat" from about 40 Hz to 400 Hz. Much like the Legacy's, the Piega shows the typical sharp roll-off below 40 Hz due to the output of the vent being out of phase with that of the undamped woofer. Even though both speakers show very similar plateau's and a similar F3 ( -3 dB point ), the Legacy's bass plateau has both a higher peak and a higher average.

Moving up to the $23K price range, we've got the Aerial 20T's. Similar to the Piega's, the Aerial's are reasonably smooth in response from the mids on up with a few low amplitude peaks and dips. Side by side comparisons though, it would appear that the Piega's are a little "flatter".

When it comes to low frequency performance, the Aerial's produced a +5 db peak centered at appr 60 Hz. Of the three speakers mentioned here, the amplitude of the peak is the same of the Piega's ( +5 dB's ), which is much lower ( 66% reduction ) than that of the +7 dB peak of the Legacy's. Even with this 66% reduction of the peak amplitude at resonance compared to the Legacy's, we are still talking about a divurgence of +5 dB's here!!!

As far as the "bass plateau" goes with the 20T's, this speaker is much more linear than either of the above. While the Aerial's also level out at appr 40 Hz and drop like a rock below that point, the upper end of the bass region is MUCH smoother. Whereas the others were contributing added output up to appr 400 Hz, the Aerial's are leveling out at appr 120 Hz or so. In effect, the Aerial's appear to offer the most controlled bass with the least amount of bass colouration. Then again, they are by far the most expensive also.


As far as low frequency extension is concerned, the Aerial's resonance peak is centered the lowest of the three i.e. 60 Hz for the Aerial's vs 85 Hz for the Piega's and 100 Hz for the Legacy. Even though the Aerial's have a resonance that is 25 Hz below that of the Piega's and 40% lower in frequency than the Legacy's, all of their -3 dB points are within a very few Hz of each other. While the graph's aren't completely legible, it appears that the F3 ( -3 dB point ) for all of these speakers are right about 34 - 38 Hz or so. How do such different designs achieve similar F3's? It has to do with the tuning of the vents and the amplitude of the peaks at resonance.

By creating a huge peak at resonance, it takes longer for the amplitude of the signal to fall off. As such, the Legacy's much larger peak at resonance allows it to achieve appr the same F3 on paper that the other designs worked harder to achieve. As such, were the Legacy's designed this way because they like the sound of massive bloat? Were they designed this way so that they could claim a lower F3? Could it be a combo of the two? We'll probably never know.

What does all of this add up to? Judged in comparison to each other and strictly talking about bass linearity, the Aerial looks the best on paper by far. Why just on paper? Because we have to factor in the added gain associated with in-room response. Our ears hear the entire presentation i.e. the speaker and how the speaker loads up / pressurizes & excites the room. As such, what looks the best on paper may not be what you like the most in your room. If you're room is properly set-up, the results on paper and the results in the room should pretty well jive. That is, at least as far as frequency response & linearity go. There are a LOT of other factors going on here though, not to mention personal preference.

What happens if the room isn't properly set up? Compared to anechoic responses, all speakers will have greater output / added extension when placed in an average listening room. While specific speaker placement comes into play in terms of the extension and amount of boost, most rooms will produce maximum ouput somewhere in the 50 - 80 Hz range. Obviously, this varies with the size and shape of the room.

The net effect is that these speakers are going to produce even MORE bass than what they already show in these graphs. Not only are we picking up low frequency output from what is called "room gain" ( "cabin gain" in a vehicle ) by pressurizing the room, we are also going to be exciting the resonances of the room too. All of this adds up to GOBS more "apparent bass". Add in the fact that this bass lacks speed and control* and you've got "bloated, ill-defined thump" running rampant.

Other than that, one has to wonder just how extended the bass response of these designs would be if they didn't have such HUGE peaks? After all, the higher the peak at resonance, the lower the -3 dB point of the speaker appears to be. Do we have to add "bloat" to get extension? How do you get around all of this and still keep good sound? That's easy but it is a completely different subject : )

What i want to know is, what do you folks think about this type of performance at these price levels? Is there anything that we can learn from this? Do we see a specific trend taking place here and in other parts of the audio market? Inquiring minds want to know : ) Sean
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* vented designs all suffer from a lack of transient response, increased ringing, over-shoot and phase problems. In this respect, a well designed port is typically "more linear" than a passive radiator.
sean
sean OP
6,231 posts
 
Ernie said: "Your posts are voluminous and helpful in reciting the liturgy, but in so doing sometimes mask objectivity. We know what we hear...and how it measured."

I guess that this is why "audio" will remain subjective forever. I know what i hear and know what i like. I'm sure that everyone else does too. The fact that what constitutes "poor sound" to me typically measures as such while others enjoy that sound makes the purchase of gear a personal decision, regardless of the facts involved. Knowing this, that's why i've stated many times over "buy what you like as you are the only one listening to it".

As a side note, there is gear that i like / is enjoyable to listen to even though it is highly "flavoured". Then again, i also realize this and would never consider such a presentation to be "accurate". Such a system would probably be owned and operated by a "music lover" more-so than an "audiophile". I don't think that either "label" is derogatory, they just signify different goals and listening preferences.

My comments were aimed at those that are interested in the "high end" reproduction of musical recordings i.e. those that seek both accuracy with musicality. Musicality by itself has many enjoyable flavours, but is only half the picture. If that is what someone prefers, so be it. I'm not here to tell them that they are wrong, i'm simply posting observations, comparing data and sharing a point of view. The fact that various points of view end up in debate is nothing new and is part of human nature.

I think that many folks have found themselves in one camp or the other, not by their own doing or ears, but by misguided suggestions from the press and marketing hype. Introducing facts into the equation may initially confuse and upset them, but in the long run, i was trying to help them become more informed and capable of making better long term decisions. After all, the more that you know about a subject, the more likely you are to be happy with the choices you make. Sean
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pbb
1,140 posts
 
Sean, I have to agree with you. You are rowing against the current though, since audio is now firmly in the "subjectivist" camp where belief replaces facts. I keep reading more and more that flat frequency response in-room is not where it's at. I remember Thiel being slammed for that "flat in-room" thing. Dr. Toole has been slammed on numerous occasions for applying science to speaker design and his work, following that of Roy Allison, in taking the room into account in the design of speakers, has been ignored. The prices are insane, but most everyone thinks that more money means better sound. Who is the writer in Stereophile, not long ago, who opined that since microphones used in recording are not linear, why should the rest of the chain be. So what hobbyists actually want nowadays is to mix and match a bunch of equipment that colours the sound this way or that way and when they are either too poor to continue, fed up with incessant "upgrades" or have gained the peer group acceptance they crave, they declare their system "done" and move on to another hobby. It simply is boring to think in factual terms and have a decent speaker system that costs too little. Strangely enough, the myriad of speaker “manufacturers” (more rightly called “assemblers” IMHO) is based on the fact that speaker design is now pretty well formulaic and that building boxes to put drivers and x-overs in is not that hard a business to get into, so that what you have are “coffin makers” building speakers and going for high margins. Aerial seems to go one better: an outside company builds their cabinets to order. So now what you have are true “assemblers” who buy drivers from one company, cabinets from another, electronic components from another, put it all together and go to market asking 30K for a pair.
subaruguru
1,376 posts
 
Sean, you're right, but there's that hint of condescension in your post that just doesn't feel right to me, as I've always been an advocate of FFR, for example, and AM a musician, for example. But I won't belabor this....

Pbb, I agree too, but must remind us that the holy grail here is often a PERSONAL spectral tilt! Since many types of listeners have different preferences here, it's reasonable to expect that assembling components (especially transducers) into a room is not necessarily simply a matter of buying a bunch of flat-response nice products. A study done a while back (was it noted in Dickason? I forget) noted that the general public preferred a 2db/octave downward spectral tilt (THAT'S warm!), musicians preferred a 1db/octave roll, whereas audiophiles preferred a 0 to 0.5dB/octave roll. How these populations were matched for sex and age would be interesting to note, as the aging male audiophile loses sensitivity up top...so is there a compensaory preference here, or is it just that cleaner, high res equipment is more easily "acceptible" if the top octaves aren't rolled.
It's pretty clear that once speaker/room setup is completed, and electronic components are set up, we chase minor spectral flavorings in cables to attain our personal "tilt". Hence the common tendency to chase rolled-top cables that are not-so-mysteriously labelled as "smooth" or "fat-bottomed", or more musical (warmer tilt?).
That speaker manufacturers all have their "house" reference tilts that they prefer is no mystery. As long as the resultant sound of these boxes IN YOUR ROOM agrees with the manufacturer's voicers then success can be had without much secondary tweaking.
Being a Bostonian, I've followed Aeriel's history, and having briefly used the same cabinet maker as Kelly, and can attest to the difficulties he had with QA of the 10T bass cabinets. I remember seeing 10T cabs lined up, seeing the minor variations in each. Must've driven a technical design engineer like Michael nuts. I jokingly offered to consult with him on QA, but had enough of a hard time getting just 20 pair of my cabinets made consistently from Pine & Baker. That Aeriel was able to get a scandinavian high precision cabinet maker with state of the science CCM to manufacture nice complex cabinet clones for him is only a credit to their manufacturing excellence. I can't comment on Aeriel's price points...nor Michael Kelly's preferred spectral tilt, but I would expect that his design work is top notch, and perhaps Aeriel's speaker components are pretty tightly controlled, yielding reasonably matched pairs that are close to design reference. Such manufacturing precision is not just the realm of the high end, bien sure, as Boston, Snell, Revel et al have sucessfully controlled manufacturing processes tightly. Although I don't generally like the voicing of most Boston speakers (except the VR-MX surround), they DO take care to make quite nice, cloned tweeters that are much better than expected. Too bad they don't know how to implement them to my liking....
Sorry for this messy post...got interrupted by Ellen's matzoh pancakes!
firebat
10 posts
 
Sean:

What's your take on Neil Patel's Avalon designs? He changed from sealed to vented enclosures in 1998 but has them tuned below 20HZ. According to Avalon literature, the speakers are designed with respect to room acoustics, etc.
sean OP
6,231 posts
 
Firebat: I'm not real familiar with these speakers, so i'll refrain from putting my foot in my mouth. At least on this occassion : ) Sean
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