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A full set of measurements for the Ayre K-3 were made in its balanced configuration, with selected measurements repeated for the unbalanced mode. Unless otherwise noted, the measurements presented are for balanced operation.

The Ayre's impedance at its line output measured 558 ohms at 1kHz in the left channel, 561 ohms in the right (279 ohms unbalanced, left channel), with insignificant variations with changes in the level control. The line-level input impedance measured 21k ohms (10k ohms unbalanced), again virtually independent of the level control.…

The Model-One features Qualcomm aptX Bluetooth, the low-latency version. Android users get high-quality Bluetooth, and AAC is the codec for Apple devices, so it's…

Description: Integrated music system with belt-drive turntable, phono preamp, amplification, DSP, DAC, headphone amp, and built-in speakers. 200W total amplification (2 × 70W to woofers; 2 × 30W to tweeters). Acoustic frequency range: 55Hz–30kHz ±3dB (under lab conditions). Turntable motor: 24-pole AC synchronous driven by digitally synthesized 2-speed electronic control. Platter: 12" acrylic with felt mat. Speeds: 33.3/45/78rpm, adjustable ±3%. Wow and flutter: <0.2%. Tonearm: 8.6" single piece, carbon fiber. Phono cartridge: Ortofon 2M Silver. Inputs:…

Digital source: MBL N31 CD player/DAC.
Integrated amplifier: MBL N51.
Loudspeakers: MBL 126 Radialstrahler.
Headphones: HiFiMan HE400S, Sonus Faber Pryma.
Cables: AudioQuest, Ansuz Acoustics, and Morrow Audio (interconnects and other cabling).
Accessories: AudioQuest Niagara 1000 Low-Z Power Noise-Dissipation System, Critical Mass Systems Maxxum equipment racks, Zanden Audio AT-1 proprietary foam bass traps/tubes (corners, 2×), AP-1 proprietary foam acoustic panels 4 × 35.5" H by 23.75" W by 1.5" D (removable and custom attached to PVC…

Evidently, I Need These Headphones
Life’s been interesting this past year. I left HeadRoom in April ’10; my daughter moved out and and I found myself in an empty nest; I rode thousands of miles on my motorcycle; met a lovely lady who rode her bike with me, and we married; constructed offices in my home to support my review work; and got my job here. Phew. In the process, I did a lot of organizing around the home, throwing out things I don’t need anymore, rearranging furniture, and ferreting bits and pieces into boxes. It felt good to…

Like almost all headphones of this type, variability in bass response due to variations in fit is observed in the raw data measurements of the headphones in five different positions. The performance of the PX 200-IIi is actually quite good in this regard; many small ear-pad headphones show significantly more variation.

The top graphs show the sum of the five positions for each channel, and is compensated for the acoustics of the head. Here we see an even, though somewhat bowed-up response, centered in the mid-range and falling to either side. The treble…

The Sennheiser PX 200-IIi
The Sennheiser PX 200-IIi (MSRP $149.95) is a general-purpose headset ideally suited for kids, students, and casual home, office, and travel use. It’s light and small, very well built, and will easily survive unending rounds between backpack, computer desk, and kitchen junk drawer. Best of all, it packs neatly into a very small size with a unique folding design making it only slightly larger than a pair of sunglasses when stowed. In typical Sennheiser fashion the design is elegant and understated basic black, tastefully mixing matte and gloss textures in…

Promises Kept
My first post was an exercise in getting all the bits-and-pieces together to create content. In many ways this is my first real post here ... and I want to keep a promise: For years I've said I would measure the effects of the various headphone pads on Grado headphones ... well, I am very glad to say finally, here it is.

To the best of my knowledge, there have been five basic types of stock Grado ear-pads over the years. From left to right in the photo above:

Small Flat Pad --- Originally the…

To my ears, Grados generally have two faults: the bass lacks authority; and there's a harsh spot in the low-treble around 2kHz. Fortunately, it appears that playing with the pads does indeed effect the sound mildly, and both problems above can be tinkered with.

I'll be mentioning some of the other measurements taken, if you…