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There's a three-band parametric equalizer, adjustable for frequency (20.22Hz-20.22kHz), level (boost or attenuation at the selected frequency), and Q (width of the filter from the center frequency chosen) for each of the three bands. There's also a "Normalizer, which sets the highest peak value to full-scale (to, I think, maximize dynamic range and resolution) and is done in real time so that it's not permanent. Thus you can go back and change EQ, fades, and other parameters, then normalize again. Or you can ignore all of this stuff and just make straight-up CD-R compilations. I include all…
Sidebar 1: Specifications
Description: Hard-drive recorder with OS 2.00, 4.3-gigabyte hard drive (as reviewed, current production offers 20GB), 4x CD-R recorder, and analog and digital I/O. ADC & DAC: 24-bit, 128x oversampling. Sample rates supported: 44.1, 48, 88.2, 96kHz. Word lengths: 16, 20, 24 bits. Analog I/O (44.1kHz/48kHz sampling rates): Frequency response: 20Hz-20kHz, +0dB, -0.3dB. THD+N: 0.002% at 1kHz, -1dBFS. Signal/noise ratio: 113dB, A-weighted. Analog I/O (88.2kHz/96kHz sampling rates): Frequency response: 20Hz-40kHz, +0dB, -0.5dB. THD+N: 0.002% at 1kHz, -1dBFS. S/N:…
Sidebar 2: Associated Equipment
Analog sources: Simon Yorke, VPI Aries Extended turntables; Graham 2.2, Immedia RPM2, VPI JMW 12.5 tonearms; Lyra Helikon, Helikon LE, Helikon mono, Benz Glider L2, ZYX R-100FS cartridges.
Digital source: Musical Fidelity Nu-Vista 3D CD player.
Preamplification: Hovland HP-100 preamplifier, Manley Steelhead and Zanden 1200 phono sections.
Power amplifiers: Musical Fidelity Nu-Vista 300, RM Labs Music Reference 200.
Loudspeakers: Audio Physic Avanti III.
Cables: Phono: Hovland Music Groove DIN/RCA, RCA/RCA. Interconnect: Discovery Essence,…
Sidebar 3: Measurements
Starting with the Alesis MasterLink ML-9600's A/D section, it took an unbalanced analog input of 1.79V RMS at 1kHz to give an accurate 0dBFS. As expected, the balanced input required 6.9V. The input impedances at 1kHz were 10k ohms and 29k ohms, respectively. The level metering appeared to be accurate, the "-1" light illuminating at 6.2V RMS balanced input; ie, exactly -1dBFS. The Alesis' overall analog/digital and digital/analog frequency response is shown in fig.1, taken at 48kHz and 96kHz sample rates, and is flat within the audioband.
Fig.1…
Fig.8 shows a similar spectral analysis, performed with 24-bit "digital black" data. Other than the expected rise in the noise floor above 20kHz, due to the oversampling delta-sigma DAC topology, the analog noise floor is as superbly low in level as I expected from fig.7. D/A linearity error (fig.9), assessed using a dithered 16-bit, 500Hz tone, was also negligible down to very low levels, confirming the excellent resolution. The waveform of an undithered tone at exactly -90.31dBFS (fig.10) reveals excellent symmetry and the expected three voltage levels. Increasing the word length to 24…
Room acoustics, and their importance, may not be subjects which we ponder daily here at Stereophile, but they are never far from our consciousness. Two recent events served to spotlight them yet again: the setting-up of our first-ever panel listening test of moderately priced loudspeakers (Vol.14 No.7), and a letter from a reader requesting advice on room problems. Both reminded us---if a reminder was needed---that although the perfect room does not exist, there are things that can be done to make the most of even an admittedly difficult situation. That reader's letter, in particular, brought…
And what about that ever-popular ceiling tile? Its absorption characteristics are actually quite similar to carpeting (with rather significant variations from type to type). But the closer the damping material is to the loudspeakers, generally, the better, and the floor is usually closer than the ceiling. Use of both tile and carpeting is most certainly overkill. The reason you see the combination so often in audio shops has less to do with acoustics than with the fact that it is a relatively cheap way to "drop" a too-high commercial ceiling, easily hiding pipes, ducts, and wiring while…
Avoid placing large pieces of furniture between the loudspeakers (between loudspeakers, the best furniture is no furniture). Imaging will usually suffer, otherwise. You might be able to get away with this if the loudspeakers are well out into the room and the credenza or whatever is back against the wall; I have on occasion used this arrangement with effective results. Similarly, a large coffee table in front of the listening location, with the attendant reflections off of it, is also usually a no-no.
And don't forget that where you place yourself will have a substantial effect on the…
The Stereophile Listening Room
Fig.1
I've discussed this room briefly in several previous articles, often with the proviso that "experimentation is ongoing." As I mentioned in the past, it measures 15.5' (footnote 4) by 20' with a 9' ceiling. The ceiling is more dispersive than normal, with open beams in Santa Fe viga style (whole barked logs supporting pine planks which form the main ceiling structure). The interior surfaces of the two outside walls are of plastered block (not adobe, as I mistakenly stated in a previous article). The other two walls are plaster over drywall…
My auditioning of the new room treatment is still in its early stages, but it does appear to be an improvement over the old. The room sounds livelier, but without harshness. Loudspeakers tried so far seem to have "lighter" sounds than before, yet are still recognizably the same loudspeakers. The room seems less warm than previously, with more clarity through the midbass region. This is most likely due to substituting a large area of reflection and diffraction for a large area of absorption (that rear wall). The result is a change in the overall room balance. Fewer of the highs are absorbed,…