Bookshelf Speakers

Update: PSB Alpha PS1 Bookshelf Speakers


Design and Setup of the PSB Alpha PS1 Speakers

PSB's marketing literature indicates that the PSB Alpha PS1s were designed to offer a more refined sound than typical computer speakers. Most small speakers accentuate the treble and/or the mid bass in an effort to sound "bigger" and to cloak their shortcomings. You can bet your bottom dollar that PSB wasn't going to resort to similar trickery with their first set of powered mini monitors, particularly since the speakers would be the next advancement of the Alpha line, a line that has earned a great deal of credibility for excellent sound at affordable prices.

PSB goes on to say that they were able to hit their design objectives with the Alpha PS1s and the result is "a speaker with an extremely smooth and refined sound with surprising output capability and solid tuneful bass response that belies the Alpha PS1s diminutive size. The response off to the sides of the speaker has the same smooth response as the sound directly in front, making the Alpha PS1s acoustically 'disappear' by projecting a large and exquisitely detailed sound image. . . " Is this a valid claim or just marketing hype? Let's dig a little deeper and find out then.

To begin with, these are lovely little speakers. The small, deep ABS cabinets have a high gloss finish that simply looks "rich". Grille-less, all you see are the metalized polypropylene woofers and aluminum dome tweeter. The tweeter's waveguide is adorned with the PSB logo. The cabinets are rear ported which further promotes their clean, sleek appearance. The speakers have a satisfying heft.

The Alpha PS1 is a 2-way design sporting a 3-1/2" metalized polypropylene main driver with an oversized magnet structure and a ¾" aluminum dome tweeter that handles frequencies over 2,100 Hz. The crossover slopes are fourth order.

Amplification for both channels is housed in the left speaker cabinet. The right speaker connection is by way of a supplied 6.5' (2 m) speaker wire terminated with right angle mini plugs at each end. This wire is 20 gage and has ferrous chokes on either end. This connection proved to be adequate, while offering one potential upgrade path for the fussy audiophile.

The amplifier is an efficient Class D design that is rated at 20 watts per channel (wpc) continuous output. This rating doubles to 40 wpc dynamic peak. The speakers are not bi-amped and I don't think this has any meaningful impact on the speakers' performance one way or the other.

The PS1s have two analog inputs - a pair of gold-plated RCA's and a 1/8" (3.5 mm) mini plug. The speakers auto select the input with the mini plug taking precedence. A very nice touch is a mono subwoofer output. This sounded like an unfiltered output during the short time I tried it, so you will want to balance the sound using your sub's internal low pass filter and volume control. Once set, the gain at the sub output will track the volume setting of the main speakers.

The rotary volume control is near the top of the back panel. There is a power indicator light on the back panel along with a USB plug that functions as a power port to charge a compatible USB device (no data).

The power supply is a universal, auto-sensing type that can be used in both North America and Europe.

I did the vast majority of my evaluation with theses speakers straddling the desk in my office. They were placed on either side of dual computer monitors and that put them about 4' apart. This was pretty wide considering my ears were only about 30" from the plane of the speakers. But the horizontal spacing was perfectly fine. The real problem was that the speakers were 20" or so below my ears - this definitely affected the sound. So I later requested the optional tilt bases. The tilt bases replace the stock bases, raking back the speakers. The tilt bases proved to be a big improvement.

I later took the Alpha PS1s into my main listening room and set them up on the shelf where my Pioneer Kuro display resides. I did this so I could try the speakers with a high resolution source that was not available in the office. I replaced the tilt bases with the original bases. The speakers were 6' apart and 6' from my temporary listening position. Go to Page 3: In Use