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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
kef1022
3 posts
 
I am so glad Sean has brought this up. My two cents on the topic are as follows:

Most Audiophiles get obssessed with the notion of high dollar speakers in the pursuit of sonic perfection. This is why it is without a doubt the most traded and talked about component. It is a combination of sonic qualities and aesthetics. What I find most interesting about this group is that compromise in tolerated more as the price of speakers increase. It is truly an odd relationship but one I have witnessed countless times (both among Audiophile freinds and the press). As Sean points out, this is certainly the case with so called "neutral" speakers costing obscene amounts of money ($25K could be used for many more worthwhile purposes than buying loudspeakers!!).
There is really something wrong with the audiophile community when in indivduals are paying crazy prices and are still upgrading and swapping, etc. As usual many getting too involved in listening to the system and NOT the music (this is in fact now an integral part of the hobby - a real shame). For those of you paying these prices for speakers my advice is 1) buy more music!! Spend a lot less on the speakers (you can get great sound for $2000!); 2)ask yourself why Audio magazines and stores do NOT do blind testing? I think we would find widely varying results that would favor less than orthodox choices. In any event, I think many kilo buck audiophiles (of which I was guilty in past lives) should really take stock of things and listen honestly (close your eyes) forget the prestige, and marketing, and "real wood veneers" etc. etc. I most recently tried this with a fellow audiophile who was listening to a pair of his exotic mini monitors...I swapped out his speakers (KEF xQ1) with modified (and yes I can just hear you all laughing) Optimus Pro LX5 speakers. In blind testing using his choice of recordings and Stereophiles test CD, he was truly unable to accept that he was listening to Radio Shack speakers!!! Laugh as you will, the fact is with the veil removed he couldn't accept the sound which moments earlier (under blind conditions) he was marvelling at. Sad.
bigtee
803 posts
 
Just to add something to Sean's post since he mentioned AR, there was that big fuss between the large Advent(a sealed system) and the JBL Century 100(which was ported)back in the 70's. The JBL had a lot of frequency deviations but would play much louder and seemed to have more drive(it was also a lot more efficient.) All of this was the "West coast sound" vs. the "East coast sound."
Seems to me the manufacturers have changed but the war goes on. Some people love the inaccurate sound(which is ok) My point is, I thought "High end" was the pursuit of accuracy in reproduction. Not that it sounded good to select people. Of course, I can also see a manufacturers position but lets be honest about it, if we are going to accept some of these speakers then why can't Bose be accepted? They cost enough for crap they are!
When you listen to a truly accurate speaker, it sounds -well-dull compared to others. However, it will sound better in a few months and with a wider variety of material once you get use to it.
On another subject, I have found that in setting up my Vandersteen subs to mate with the 3A Signatures, that when set correctly, they do sound lean. The Vandy subs can be adjusted for a "Q" of just under .5 to something along about a "Q' of 1.5.
As you go up in Q, the bass sounds more prominent. As you go the other way, it gets very, very tight and sounds lean. Now of course you can raise the level, but then output of the subs is exceeding the output of the mids and highs of the main speakers. Everything can actually be shown just as Sean explained above. The Vandersteen 3A Sigs seem to be set for a Q of about .7 or so. The subs integrate well set at about a Q of .6 to .7 You can set the Q lower but the bass becomes very lean and detaches from the music a touch. I really don't see how you get a sub to match without some control over the Q differences between the lower section of the mains and the sub.
Roy makes a valid point above about phase relationships. I became convinced sometime ago that phase and time was an issue. I still stand convinced on this subject. One of these days, I'm going to give one of his speakers a run.
sean OP
6,231 posts
 
Roy brings up some great and very valid points. Speaker design is obviously VERY complex and loaded with design trade-offs. Having said that, Roy's comments also point out that the room has to be taken into consideration i.e. how the drivers "blend together" and "load up" in the actual listening area. Since most designers / manufacturers don't take all of these factors into consideration, they end up with a product that lacks "universal" application and / or works well in some aspects but is quite limited in others. All of this for only a few thousand dollars : )

One of the points that Roy mentions is the phase shifts that take place within the audible band when using multiple drivers. Part of why people "love" single drivers is that this is less of a problem. Instead of dealing with multiple different radiation patterns, transient responses and phase shifts, you have one point source radiator. Most all of these problems are drastically reduced, resulting in a far more "unified" or "cohesive" presentation. You don't have to worry about how one driver blends with another because you've only got one driver.

This is one of the reasons that i love my Ohm F's as much as i do, as limited as they are. Being a single driver design with the horizontal radiation characteristics that they offer, they do some things that no other driver / speaker can offer. At least, no others that i've heard.

Drubin: Naming names gets hard to do, for both good and bad reasons. The "bad" reasons are obvious i.e. potential legal ramifications. Believe me, i've gotten more than a few emails about this subject. Only thing is, someone can't sue you for telling the truth using statements that are verifiable.

As far as the "good" goes, i have a hard time finding any "manufactured" speakers that are worth recommending in stock form. It's hard to use something as an example when you can't find a suitable sample.

If you want some basic recommendations, avoid ports and passives. Both introduce increased amounts of resonance and phase shifts into a system. I've posted links to a few discussions that cover this topic that i had over at AA, but i'll see if i can find them and post links to them again later tonight. Sean
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PS.... Obviously, i'm NOT familiar with EVERY speaker or audio product out there. It is quite possible that there are some excellent examples out there, i just don't know of them or enough about them to use them as a reference.
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drubin
3,275 posts
 
Avoiding ports and passives is a tall order. If I'm not mistaken, that would exclude most of the phase-and time coherent designers out there, including many models from Thiel (my 2.4's have a passive radiator and a Q of about .8), Vandersteen, Meadowlark, and even GMA (the Europa is ported).

My request for naming names is not to ID who is good and who is bad but to illustrate what a high Q speaker sounds like vs, a low Q, etc. etc. I'm looking for organizing principles and examples of the members of the various camps, that's all.

"In this corner, we have Brands X,Y,Z, who belong to the bass uber alles school and get there by doing.....And in this corner, we have the accuracy school....."
eldartford
4,262 posts
 
Why fight this sealed vs ported battle?

GO PLANAR!
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