Vandersteen 5Aa Carbon--any 5a owner's opinions?

Bass - Richard's system is really good - maybe the best. However, technology moves on and no stereo pair of subwoofers can flatten out all the room modes encountered in a real world room. An eleven-band analog equalizer can't match the 100's of poles a DSP-based digital filter can provide, and can't alter the subwoofer phase across the passband.

The answer is a distributed subwoofer system like the 4-woofer Audiokinesis Swarm and digital room correction (250 hz down). Through proper (asymmetric) placement it can completely flatten the room response in combination with digital room correction like Meridian's MRC system. With this type of system, the Seven is overkill.

It would be nice if Richard put both the 5a tweeter AND the Carbon / Balsa 4.5" driver in the Quatro Wood CT, because with the Swarm you don't need anything bigger. Also the 7 tweeter is unique - no phase plug. The 5a and Quatro tweeters are carbon monolithic domes without the "C sandwich" construction of the 7's dome. Not sure if this makes a difference, but the 7 is unique in more ways than one.

When I say flat, I mean with a smooth response over most of the room, such that the room's dominant nodes and anti- nodes ( i.e. suck out) do not dominate the "Rayleigh Region" where the wavelength of the sound and the room dimensions are of the same order. The problem with Richard's approach is that stereo speakers usually end up in symmetrical positions in the room, so the best you can do with the equalizers is to reduce the magnitude of the peaks at the principal listening position. Look at the settings of your left and right equalizers - unless you have a highly asymmetric room, they are probably set the same. This means that the sound may be pretty good in your favorite chair but it is very uneven everywhere else in the room. This causes another form of coloration, reverb, that tells your brain you are in your 16 ' x 22' x 8' sound room, and NOT really at the recording venue.

In addition you can't do much about suck-out, since Richard only puts a 400 watt amp in the 7's and a 250 watt amp in the Quatro's. You would need much more power than this to fill in the suck-out that plagues every normal size listening room I've ever been in, but is notably absent in a concert hall, because of its size.

The only answer is to spread the bass transducers around the room so that you normalize out the dominant room nodes, and then trim it with a really good DSP room correction software calibration with (ideally) individual settings for each woofer, and at the very least for the left, right and .1 channels, like Meridian's MRC. If you do this, (and I have with two Quatros and five distributed subwoofers), the room literally disappears, and you will swear you are at the recording venue.

This is fairly new technology, but the concept has been analyzed by Earl Geddes, Fred Toole, Bob Stuart of Meridian, and Duane LeJeune of Audiokinesis. REG reported on the Audiokinesis Swarm system in The Absolute Sound earlier this year, and stated that the Swarm produced the best, most accurate bass he had ever heard - and he did his audition without any equalization. With digital room correction, it gets even better, but the corrections are much smaller than they would be for 1, 2 or 3 woofers. (With my set-up I have seven woofers which all end up about seven feet apart and all around the room.)

I was so bowled over by this, I decided to upgrade my fabric Quatros to the carbon versions, but I am thinking that the Swarm may make the Treo's sound just as good, since they dominate below 80 hz.

BTW, if I blindfolded you and asked you to point to the subwoofers, you couldn't do it - the bass ambient sound is completely non-directional....as it should be. There is no suck-out and the only nodes appear right in the room corners, but at greatly reduced magnitude. The impression this gives is a much more natural acoustic environment and, with classical music, much like a good concert hall. It is spooky good.

Thanks, Johnny. Richard says the same thing. The digital reconstruction filter is the key ingredient. I use a Meridian G68XXD which uses their patented apodizing filter and 24 bit / 96 kHz digital processing of all inputs. I honestly can't hear a difference between an analog signal from my Pass XP-15 phono stage going direct to my amps (through an ALPS Black Beauty pot), vs. through the Meridian, except that the Meridian has much more coherent bass due to the Meridian Room Correction (MRC). I have also fooled all the golden ears in the St. Louis Gateway Audio Society, who simply don't believe they are listening to digital when I play vinyl.

This may be unique to Meridian's latest software however, because I couldn't stand digital before I got this setup. The only other system that I am aware of that sounds this good is the dcs stuff the pros use. I got to spend a half day in the DTS mastering center in Calabasas, CA listening to their DTS Neo X software playing digital tracks through an 11.2 speaker setup. Most incredible sound I've ever heard. It was all based on proprietary DTS software and custom dcs digital DSP's and ADC/DAC's. I asked how they did it and they just smiled, but commented that the computing throughput and the reconstruction filters were critical.

The point is, you have to go digital for the best room correction, for multi-channel and for any recording that's not vinyl. (Even for most remastered vinyl, the signal has been digitized in the recording process.). For me that means using Meridian processing - nothing else a consumer can buy compares.

Added footnote - I've had the Meridian DSP speakers in my room and compared them to the Vandersteens. They are pretty good - especially the big ones (7000 and 9000 series), but not as good as the Vandersteens. Even the Meridian techs who have calibrated my room admit that. What Richard has accomplished with his four driver architecture and crossovers is magically. The only way to match what he has is a single full-range, phase coherent driver, but I've never heard one big enough to reproduce an orchestra.

Second added footnote - if you read Meridian's White Paper on Room Correction, the target function they are optimizing (with up to 60 digital filters) is the room's reverberant field - in essence the famous waterfall chart.  Below 250 Hz, the reverberant field is much more important than the direct response.  You can only really adjust the direct response with an 11-band analog equalizer to correct gross errors.

Correcting the reverberant field can make the room disappear.  Richard has always said your ear-brain can do this correction itself, because you can recognize your spouse's voice in whatever room you are in.  He's right, but I'm not sure it applies as well for a complete orchestra in a BIG hall.  A crucial difference is the sound source - the Vandersteen approach works well for point sources, but an orchestra can consist of over 100 instruments, spread out over a "field of view" of up to 90 degrees, (sitting in the 20th row).  In addition, the back wall reflection in a concert hall is 40-100 ms after the direct sound.  In your room, the sound bounces off your walls many, many times in this interval.  As a result, the room modes can completely mask the hall ambience in the recording.  This, I think, is where the Meridian approach, along with multiple, asymmetrically distributed subwoofers (4-7) has a big advantage.  

One final note on where both Bob Stuart and Richard Vandersteen completely agree - room correction above 250 hz is deleterious to the sound.  The Meridian MRC approach makes no "edits" above this frequency.