Celestion SL600si loudspeaker & DLP600 digital equalizer 1992 System Context
The reference system used to audition the SL600Sis and the effect of the DLP600 is the same as that used for my past few reviews. The all-digital nature of the DLP600 meant that analog playback had to be (temporarily) abandoned, however. Source components consisted of a Meridian 602 CD transport driving either a VTL Reference D/A processor or the Audio Alchemy DDE. Digital interconnect between the Meridian and the DLP600 was a 1m length of AudioQuest's new Digital Reference; between the DLP and the DACs I used a 0.5m length of the Mod Squad's Wonderlink. Preamplifier was the Melos headphone amplifier, connected to either a pair of Mark Levinson No.20.6s or Audio Research Classic 120s with AudioQuest Lapis single-ended interconnect.
The speakers were bi-wired with 2m lengths of AudioQuest Midnight (bass) and Sterling (treble) and sat on 18" Celestion Si stands. This put my ears just above the top of the cabinet, which is the '600's optimal listening axis. Thin pads of Blu-Tak damping material coupled the speakers to the stands, which were spiked to the floor beneath the rug, their center pillars filled with lead shot and sand. (footnote 1 The listening room has a dedicated AC feed with hospital-grade outlets, and all line-level components were plugged into the excellent Power Wedge II isolation unit, the subjective effect of which is to make the silences more silent, to the benefit of the system's dynamic range.—John Atkinson
Footnote 1: I note that some mainstream writers still laugh at those of us who take such care in the siting of our loudspeakers. I am in the middle of a project where I use an accelerometer to measure the effects different loudspeaker stands and interfacing materials have on the vibrational behavior of a loudspeaker's enclosure walls. The preliminary results show that these effects can be considerable, but not necessarily predictable or intuitive. More on this subject next month, Deo volante.