Audio, hi-fi and car audio - Subwoofer opinions and/or suggestions

Hi

I am planning to buy a subwoofer to complete my system. I have a
Yamaha RX-740 RDS receiver and 5 Celestion F10 speakers in a small
room (about 4x3m). I use it mostly for music (music DVDs).
I am thinking of spending about 300-350 euros (£200 - £233).

Some models I am considering:

Freq. Response Power Diameter
Yamaha YST-SW315 20Hz - 160Hz (-10dB) 250W (10% THD) 250mm
Infinity Beta SW-10 30Hz - 150Hz (±3dB) 150W RMS (0.1% THD) 250mm (10") CMMD
Celestion S80 35Hz - 150Hz (±2dB) 100W 210mm (8")
Tannoy mX-SUB10-M 35Hz (-6dB) 75W RMS/150W Peak 250mm (10)
KEF PSW 1000.2 38Hz - 180Hz (±3dB) 100W 200mm (8 )

The Celestion is a down-firing type, and I fear that it may produce
more dB to annoy my downstairs neighbour than in my room. Any idea
if this would be a problem ?

Yamaha says that the subwoofer produces much of the sound from its
horizontal port and it has a reflector underneath it, so it might
be better on that respect. It was also recommended by the shop.
The reason why I am a bit hesitant is because Yamaha does some
strange things on their subwoofers specs:

1 - they quote a frequency response 20 Hz - 160 Hz at 10 db instead
of the usual 3 dB (Celestion quotes at 2 dB). This doesn't
worry me, since their manual has a graph of its "frequency
characteristics" which shows a flat response down to 30 Hz,
which compares well with all the other models.

2 - They quote its power as:
Amplifier Output (100 Hz, 5 ohms, 10% THD)
YST-SW315............................. 250W

Infinity quotes a lower power but with much less distortion:
Maximum Amplifier Output: 150 watts RMS
(20Hz 150Hz with no more than 0.1% THD)

I suspect that what is happening here is that Yamaha is trying to
impress buyers quoting an high power rating and scaring some of
them (or at least me) with the distorsion value. Probably they
could quote a lower power with a distorsion similar to the Infinity.
Is this the case or has the Yamaha really a lot of distorsion ?

The Tannoy and the Kef, on paper, don't seem competitive (in fact,
neither the Celestion). Any opinions ? At this time I am leaning
towards either the Yamaha or the Infinity.

Thanks in advance

URLs for all these models:
http://www.celestion.com/products/fseries/s80.html

http://www.yamaha-audio.co.uk/speake...ers/yst-sw315/
http://www.yamaha-audio.co.uk/pdfs/s...s/YSTSW315.pdf
http://www.yamaha-audio.co.uk/pdfs/manuals/YSTSW315.pdf

http://international.infinitysystems...uage=ENG LISH
http://international.infinitysystems...10%20OM-UK.pdf

http://www.tannoy.com/product.cfm?ID=155&Page=1

http://www.kef.com/products/subwoofers/sub1.html
http://www.kef.com/products/pdf_broc...ish%202003.pdf

(BTW, the crossposting to misc.test is because my server doesn't have
the uk.* groups. I have redirected Followup-To the uk.* groups so that
people don't post accidentally to misc.test (although I think the auto
responders have been turned off years ago, or at least need the word
"test" in the Subject ). I will read the replies in google.)

--
http://www.mat.uc.pt/~rps/

..pt is Portugal| `Whom the gods love die young'-Menander (342-292 BC)
Europe | Villeneuve 50-82, Toivonen 56-86, Senna 60-94