Before I move on, a bit of my little bit of experience with the brand:
TAD TSM-300 Many years ago, the TAD TSM-300 (good description here) and its twin Pioneer S-LH3 was a great hit in Asia. I owned a pair of the former and greatly enjoyed its highly resolving and uncolored sound when matched with SET amps. IMHO, it is best heard when placed horizontal, like in the studio. It has long been discontinued but is much sought after in the second-hand market. A poor man's TAD!
SP-21BS-LR This is a somewhat scaled down version of the SP-41BS-LR. Importantly, the same tweeter is used but It has a 4" woofer (instead of 5.25") and the frequency response is 65-20kHz (the bigger brother goes 10 Hz lower). Like its brother, it is 6 ohm, 84db (Pioneer Product Sheet).
The SP-21BS-LR did not get much attention from the same press, but a good write-up of a similar associated package using 4 of these can be found at cnet.
The SP21BS-LR is reasonably well built. There is a internal front-to-back partial partition/brace between the tweeter and woofer. The design shows thoughtful features unusual at the price. The tweeter has a flared baffle, albeit plastic. The woofer unusually is not mounted directly on the cabinet, but on a circular bed. Crossover components are of reasonable quality. It is certainly worth every penny of its price. Compared to other much more expensive small speakers it is rather light, and that Pioneer "label" is just an awful piece of tape!!!! No matter, beauty lies within.
As you can see from the top pic, the protective mesh on both drivers can be removed. Use a small jewelry screwdriver to gently pry those out, but be careful! They are held in place with a little adhesive applied here and there in the circular groove.
SW-8 The subwoofer is not big and has an 8" woofer and there is not much in the spec's. However, this set of measurement, -3db at 31Hz, is impressive to say the least!
I was impressed from the word go. The Pioneer's threw a wide soundstage and was clean and composed. It was everything the reviews said: midband clarity, smooth high frequency and surprisingly useable bass. For classical music I thought it did nearly as well as other mini monitors I have heard.
To put it in perspective: No, they were not as good as the Sf's, which is best-of-the-best. The resolution is lower, there is less sheen on the massed strings, and it certainly did not go as loud. While I could play a good symphony, there was something a little restrained about the Pioneer.
Adding the SW-8 solidifies the sound a notch and helped the overall dynamics a bit, but the basic characters of the SP-21BS-LR remained. But I can say the subwoofer is very musical, with good speed and clarity, although I feel it did not go as deep as the measurements indicated.
Then I brought the SP-21BS-LR back to HK. I left the SW-8 behind in NYC.
Digital: YBA WD202
Preamp: Leben RS28CX
Amp 1: Rotel RB870BX (review here)
Amp 2: Western Electric 124B (briefly, here)
Integrated Amp: McIntosh MC-1700 (last blog entry; here)
Just as in NYC, the Pioneer produced a controlled and refined sound whether I used a solid state or tube amp. As the placement was high up, the soundstage was also commensurately high. In this repect, its vertical dispersion is not among the best I have heard. Even so-positioned, the bass remained quite serviceable when I listened to big symphonic music. As before, the sound became a bit restrained when I cranked up the volume. But it was never embarrassed by partnership with much more exalted gear! The more you give it, the better it performs.
Conclusion A superbly controlled loudspeaker with no significant weakness. Nothing comes remotely close at this price.
Now, don't you think the humble little Pioneer bears more than a little resemblance to its professional bigger brother, the currently hot TSM-2201-LR? Watch this space for report on that!