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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
gs5556
1,234 posts
 
One thing that's overlooked when analyzing speaker frequency response graphs is that they don't tell the complete story. It is assumed that a "flat" response oozes performance but that is only true in a laboratory environment. In the listening world: a box speaker has two cabinets - one behind the driver (the enclosure) and one in front of the driver (the room). The room effect is very similar to that of the enclosure - that is, it affects the frequency response and other parameters the way that the enclosure does only to a less extent due to the increased volume.

So when a crossover is designed based on the driver T/S parameters, enclosure volume, port size, etc, the attempt is to not only optimize the frequency response but phase, impedance, incursion, acoustic power etc. When all is well and done, these are measured without the effects of the room (anechoic chamber) and presented for all to see. But this doesn't really say much about the sound in an enclosed room. The room itself will throw these carefully crafted measurements out the window. That's when the listening tests come in. By tweaking this cap here and that resistor there, a best sound is determined and the stuff is packed and marketed. But after the tweaking process, the original perfomance curves are different than the original design. The in-room listening process forced it to depart from "flat". So what? If it sounds $15k better than the other stuff, well...

It all boils down to how it sounds. Measurements and specs just confuse things with respect to speakers, IMO.
onhwy61's avatar
onhwy61
5,218 posts
 
For the most part audiophile oriented speakers have always had "tailored" responses. When compared to to accurate studio type monitors the typical audiophile speaker provide excess warmth, image depth and various forms of treble emphasis. Is the issue presented above really a question of someone simply not liking the specific tailoring of a recent group of speakers?

The response curves presented in Stereophile are not actually speaker response curves. John Atkinson performs various measurements 1 meter at the tweeter level and the graphs derived are an anechoic average across a 30 degree vertical and 30 degree horizontal window with a "complex sum of the nearfield responses (taking into account acoustic phase and distance from the nominal farfield point) plotted below 300Hz." It's not altogether clear that this type of measurement corresponds accurately to what the speaker will sound like in an appropriate room. It's interesting that Stereophile did not provide the one-third octave average in room response for any of these speaker.
sean OP
6,231 posts
 
Mejames: I have a LOT of respect for John Dunlavy even though i disagree with his point of view on the audibility of wire / cable changes in a system. Having said that, there are certain parts of his speaker designs that needed help. He acknowledged this when he upgraded / re-designed the SC 4's to the 4A's. While the 4A was "technically more correct", it seems like he fixed a few problems and introduced new ones. I think that a lot of the new problems were related to the new crossover design, which was far more complex. Parts heavy crossovers reduce the amount of control that the amplifier has over the drivers ( more "middle men" to deal with ) and reduce the detail that a speaker is capable of. My Brother's actively crossed quad-amped system is similar in design theory to that of the Dunlavy's. It is both more advanced yet much simpler in nature.

Lancel2000: You can't stop the bleeding once you've already got a wound. You can try to minimize the damages though, but various methods may introduce their own side-effects. Depending on the severity of the wound and the approach taken to try and "band-aid" it, the results and side-effects will vary.

Bigtee: I'm not quite certain how Vandersteen is working his "active coupler's", but they are some type of "fancy" passive radiator. I will give Richard credit though as he is a far more realistic designer than most speaker "engineers". He at least provides the ability to fine tune the electro-mechanical properties in his top of the line speaker and in the active subs. On top of that, he also uses more internal damping material than most vented designs, reducing internal reflections and reducing cabinet resonances. He needs to work on his tweeters though as there is something funny going on there. Most amps have a hard time loading into them, causing the top end to both soften in quality and fall off in output.

Gs: You are trying to introduce products designed for the "real world" here, but doing so in a back-handed manner that is not nearly as complimentary as it should be. From what i can tell, you slapped the people that you were trying to compliment and made a case against that type of product for those that seek "musical accuracy".

You basically said that if the device measured more non-linear in actual use after hand-tweaking but sounded "good", that was acceptable. As far as i knew, the whole idea behind hand tweaking / customizing is to improve linearity, which improves the sound also, under the actual operating conditions. It was not meant to introduce further signal degradation or specific colourizations. Then again, i want to hear what is on the recording, not have all the recordings sound the same or cater to a specific presentation. Maybe we have different goals.

Other than that, I'm all for products that are designed to work with their environment. I just don't know where they are or who makes them. To me, such a product is the MOST "technically correct".

The only problem with such an approach is that to market such a product and have the end user achieve the same results in their home, the product has to be operated within the boundaries of the original design parameters. Operating said product out of the design parameters basically negates all of the research and special attributes that went into making it what it is.

How many people ever read their product manuals? How many people actually follow detailed installation instructions? Not many from what i can tell. Between the lack of familiarity with the product, poorly written manuals and / or manufacturers that don't know how to design properly, most people never experience the joys that a good system that is PROPERLY installed can bring them. For that matter, most of the "professional installations" that i've seen were ALL wrong. With that in mind, how many "civilians" do you think can get it right???

As such, the manufacturer / sales rep / dealer / installer has to know the specifics of how a product is to be used and the end-user has to follow those directions. If one likes a product but it can't be used as intended in their specific installation, it should be avoided. Placing a speaker out in the room that was designed to be placed near the wall ( or vice-versa ) will negate any of the "real world" benefits of that design. Not only will such a product probably deliver far poorer performance, there will be quite a few side effects too. Hand tweaked / room optimized designs are only as effective as implimented.

Onhwy61: Good points, especially about the one-third octave averaging graphs. My guess is that the results weren't very flattering, hence their lack of inclusion. Sean
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holzhauer
201 posts
 
I find it interesting the great importance assigned by many to linearity when in fact the human ear is anything but linear. In chapter 3 of the Master Handbook of Acoustics attention is given to the effect of the ear canal on incoming sound waves. Sound pressure meters do not measure the spl at the eardrum. They measure the spl at the meter itself. I suspect that our desire to measure everything in our physical environment has hastily overlooked certain as yet unquantified psychoacoustic realities. It seems to me that most forms of human language and vocabulary have yet to evolve such that each of us can converse understandably about what we hear. Perhaps one could be characterized as a bass nut which said description I think would be the audio equivalent of a racial stereotype or one could be characterized as an individual who assigned great or at least equivalent importance to the bass or percussion musicians of any given musical event. In short, I personally have far more faith in a large group of people who are familiar with live music calling a system realistic sounding than I do a set of scientific measurements.
bigtee
803 posts
 
Sean, I think your paragraph on setup is probably the most important bit of information to come from this thread. I understood this many years ago when I first got into Vandersteen. These speakers are a pain in the butt to get set up correctly and it has taken me years to really figure it out. Once set up, they are pretty impressive.
As for your statement on high frequency roll-off and drive problems, I don't know about that. Any test I have seen shows them flat out to past 20K. I have used special measuring instruments and a signal generator in my room and as mine sit, they are pretty flat to 20k.
If you are refering to the Vandersteens sounding rolled, well that's another story. It is partly the design of the speaker. Since the tweeters acoustic output arrives with the mids, they don't throw a bright sound at you(although with the wrong electronics, I have heard mine bright) Also, setup is so important and Richards suggestions are just that, suggestions.
I have had many speakers through my room and the Vandersteen's do not sound rolled in comparison to any of them in this setting. I have found them articulate, with pristine highs. If I had a gripe, it would probably be more in the midrange arena.
If you ever make it to the Charleston area here in SC, you're more than welcome to stop by. We have good seafood and a beautiful city. I think you could be pleasantly surprised on how a Vandersteen can really sound as a bi-product of years of fine tuning a system.(Of course along the way, I have thought of dumping the whole thing and buying a new boat!)
Right now, I'm disappointed in high end audio. It has lost something along the way. I've been at this for over 35 years and I've never been more disappointed with much of the new entries that are coming out.
Everytime a new product comes out, everyone jumps on the bandwagon only to dismiss it a few months down the road for the latest and greatest.
People can argue against accuracy and argue about this and that. However, I have never heard an accurate speaker(relatively speaking) that didn't sound decent. I guess in the process, the designer pays attention to the other stuff also.
With all the variables in audio, which ones do we want to take as truth. I mean, my kids think their car stereos are the end of the reproduction chain. Hey, it sounds good to them. So, I guess it fits into the high end---it sounds good. So what if it has a 15db boost at 80hz. And this is what I reading from some of the posters here. High end redefined!
We have to start somewhere and I feel accurate acoustical output is it. I think it is better to tune the room than tune the speaker.
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