Quad follow up review:
QUAD 2905 SPEAKER REVIEW
The following is a listening synopsis of my experiences with the new Quad 2905 Electrostatic loudspeakers over the past year.
Remember the listening room acoustics and the set-up is as critical as the speaker chosen. The Quad’s are electrostatic dipoles so room placement relative to boundaries is important. Because of the dipole radiation pattern sidewalls/floor and ceiling are not an issue but being able to maneuver the speakers some reasonable distance from the back wall is important to get the right mix of reflected to direct sound. In my two setups the speakers were 8 feet apart – edge to edge – and I sat 8 feet away with the speakers angled at about 20 degrees and the speakers where 4 feet from the back wall in room number one. They were 7 feet apart 3 feet from the back wall and I was sitting 7 feet away in room number two.
First off, if brand new do not just plug them in and listen – I was so excited about getting them set-up and working I started listening immediately and they sounded awful. Then I realized, after reading the instructions, that a minimum charge time is involved – lesson learned – I should know better. In fact, I have since learned that they recommend 200 hours of normal playtime before they are totally ready for prime time
Anyway, the Quad in a word is an INTIMATE speaker. By intimate I mean it works best when you sit close and play at reasonable volume levels. You know those 3 o’clock in the morning occasions when the rest of the world is asleep and you’re alone in your sound room with a glass of wine and a great acoustic recording. The near/mid-field listening position is possible because of the so called “Point Source Array” of the panel – most large panel dipoles need you to be 8-10 feet away for the individual drivers to integrate. The Quad being one large point source driver allows for this excellent close proximity listening.
The theoretically ideal speaker, according to Quad, has always been considered to be a SINGLE point in space radiating sound equally in all directions from that point with perfect amplitude, time and phase. Think of it like a stone dropped in a pool of water and the sound radiation wave simulates the ripples radiating coherently outward from a central point. Why is this important you ask? Each musical sound is comprised of several different tones, or harmonics, each having its own amplitude, time and phase relationships with the others. To completely preserve the unique character of each sound, it is necessary to preserve all of this information. In other words, the loudspeaker's amplitude, time and phase response must all be accurate. Many speakers can do a good job of preserving the amplitude relationships of music, but they usually fall short at preserving time and phase relationships.
Timing errors can also cause the loss of directional or imaging information. With most speakers, the only dependable clues you are given about the location of the sound are contained in the loudness of each speaker. If the left speaker is playing a given instrument louder than the right, then the sound of that instrument seems to be located closer to the left speaker. This is why the "sound stage" that some speakers produce exists only between the speakers. In contrast to this loudness type of imaging information, your ear/brain interprets real life sounds by using timing information to locate the position of a sound. In real life, your ear perceives a sound as coming from the left because your left ear hears it first. That it may also sound louder to your left ear is secondary. Your ear is set up for, and is much better at, determining location from time information rather than loudness information.
The advantage the Quad has with a large SINGLE driver acting as a spherical point source is the ability to maintain the amplitude, time and phase with accuracy not generally available in muti-driver speaker designs. “In the Quad 2905 there is a circular array of electrodes with accompanying delay circuits on the middle two panels to approximate this spherical radiation point source pattern. “The centre two panels in each Quad ESL Loudspeaker incorporate concentric rings (8 of them) on the outer grid-plates around the diaphragm. Each ring is subjected to a minuscule time delay and attenuated by its own individual circuit, the sound spreading gradually from the centre outwards through each successive ring. This carefully structured delay line creates a near perfect spherical wave front originating from an apparent point 400mm behind the loudspeaker. Imaging is pinpoint and there is no ‘sweet spot’ – all listeners receive a full sonic presentation.” The 2905’s have 4 bass panels (total of 6 panels) whereas the smaller Quad 2805 has just 2 bass panels (Total of 4 panels).
I made frequency and time measurements with my ETF system – which is the one I use when setting up studio systems. Directly on axis at 1/2 meter the Quad measures very flat – in fact what is nice is that the bass response is very linear up close – a lot of speakers need room to develop bass energy. Panels tend to have an equal frequency response launch in the near field as well as the far field. As you move away from the center position in the Quad in any direction the hi-frequency response falls off quickly so the angle of the speakers relative to the listener is very important depending on the tonal balance you want to achieve in your specific room.
Over the years I have owned Quad 57’s and the Quad 63’s but not the more recent Quad 989 or 988 so the comments I will make on the 2905’s will be as compared to the earlier versions of the Quad electrostatics. I listened to the speakers in two different rooms. One room is 23x16x8 and the other is 12x16x8 feet (speakers on the long wall). I preferred them in the smaller room. My memory of the older Quads are ones of an extremely coherent speaker with lightning fast transients very low distortion and superb midrange at the expense of deep bass and wide dynamics. Over the years many subwoofers/woofers have been used with the older Quads to try and extended the limited bass response and improve on the dynamic capabilities without much success. The problem has always been one of integration --- the Quad is a velocity device whereas dynamic type subs are pressure devices.
With the 2905’s the soundstage appears to start about 1 foot behind the panel and move backwards and outwards. I found as you increased the power amplifier power to the panel the sound changed a bit in terms of the tonal balance. Smaller amplifiers sounded more ‘mid-rangy’ bigger amps sounded more ‘bass-weighted’. There is a point with the bigger amplifiers where the speaker starts to sound dynamically restricted or compressed regardless of how hard you push it. I was never able to shut the speaker down (Quad has a built in protection circuit) but the speaker definitely has a limit to the dynamic range it can deal with. Maximum power handling is 100 watts per channel at 8 ohms before the protection circuit activates. I think room size and the type of music you listen to will be the determining factor on the power of the amplifier you ultimately choose.
I found the Bryston 2B SST (100 watts per channel at 8 ohms) was an excellent match in my small room but I also tried the PP-60 (60 watts), the 3B SST (150 watts) and the 14B SST (600 watts) as well as a tube amp (80 watts) and 2 Class D amps (100 and 200 watts). The other aspect I found surprising was that the Quad’s appear very easy to drive. I did not expect that given that Electrostatics are huge capacitors and generally not an easy load for an amplifier. Anyway, even the PP-60 was singing along with no sense of strain.
I can listen to these Quads for hours and never feel that I want to ‘turn it down’. The lack of distortion is really exceptional. There is no sense of strain in the sound and voices are in the room with you. Every once in a while I would get that “was it real or Memorex” feeling. It is what I refer to as ‘startle effect’ – when your not sure if that sound you just heard was on the recording or some extraneous noise in the room. Complicated productions like mass chorus always sounds defined and you can easily delineate each voice or instrument in the recording. The really surprising characteristic is the bass response. In both rooms measurement indicate that there is usable bass down to about 35 cycles but it sure sounds like it goes deeper. Maybe it’s a function of the 6dB roll-off of the dipole panel and the 6dB room gain interacting in a positive way? Big big improvement over the older versions of the Quads.
The 2905 have definitely improved on the older versions (especially bass) in all areas but there are two issues I feel need to be explored. The transient response of the 2905 speaker seems slightly slower than I remember in the Quad 63’s. I think part of the issue may be that the extra bass panels give the speaker a much more extended frequency response in the lower bass area so acoustically the tonal balance makes the speaker sound a touch slower in comparison to the older Quads. Maybe more weighted is a more accurate description. Also this balance seems to be changing the more I use the speaker so some of this may be a break-in issue? My guess is the smaller Quad 2805 (2 bass panels instead of 4) may in fact sound more like the older Quad 63’s than the bigger 2905 version. I never tried the Quad 989’s or the 988’s so I do not have the benefit of comparison on that front. Dynamics are better than in the original but again they will not compete with big planar magnetic or the more traditional dynamic type speakers -- horns – don’t even go there.
Continued on next post:
