Hi Everyone:
A while back I has asked this question but can't find a good answer, thus part II of the same question!
In summary:
I purchased an used but in very good condition b&w nautilus htm1 center speaker, which is a relatively large center:
http://bwgroupsupport.com/downloads/...0InfoSheet.pdf
The speaker sound really good and all drivers are working, I tested all the drivers individually to make sure they all are working; however, when I ran the Audyssey XT32 on my Marantz AV7702 MkII preamp, the Audyssey would set the crossover for the HTM1 at 150Hz, which seems to be super high, consider this speaker can go down as low as 50hz. I reran the Audyssey many times and have moved the mic around a bit, but still have the same results. I have a numbers of other center speakers, from Klipsch RC64II, Emotiva C2, Onix Rocket Bigfoot RC200, Infinity Alpha 37C to a much smaller B&W cc6 s2, all of them were set up on the same preamp, on the same shelf and all other centers are has the crossover set by the Audyssey at around 40-80Hz. Even my small in-ceiling Atmos speakers are crossover at 100hz by Audyssey.
When I asked this question the first time, many folks told me it might be the room interaction or I have a null zone that would caused that. Anyway, last weekend I decided to do some tests with the low frequency sweep and measured the response from a few of my other center speakers to compare are here are the results.
Test Parameters:
Preamp: Marantz AV7702 MkII, set to
Puredirect, only the test speaker is connected to the amplifier (Left Ch)
Amplifier: Emotiva MPS1 (200W/ch)
Radioshack sound meter set at two locations: 3.3ft (1m) from the center of the speaker, see pictures and 10ft at the primary seating position
Volume is setting at 0 (Ref. level)
Speakers Test:
1) B&W Nautilus HTM1 (seal): Frequency Response: 49Hz – 20kHz ± 2dB on reference; Sensitivity: 90dB spl (2.83V, 1m)
2) Onix Rocket RC200 (vent): Frequency Response: 50 Hz to 20 KHz (± 3 dB); Sensitivity:91 dB (@ 1 watt / 1 meter)
3)Infinity Alpha 37C (seal): frequency response 45-22,000 Hz (±3dB); sensitivity 91 dB
Result at 3.3ft (1m)
Speakers 20 hz 30 hz 40 hz 50 hz 60 hz 70 hz 80 hz
B&W HMT1 81 db 81 db 82 db 90 db 97 db 98 db 103 db
Onix RC200 88 db 92 db 93 db 94 db 101 db 99 db 101 db
Infinity Alpha 37C 80 db 82 db 78 db 85 db 92 db 91 db 97 db
Result at 10ft (primary seating)
Speakers 20 hz 30 hz 40 hz 50 hz 60 hz 70 hz 80 hz
B&W HMT1 81 db 87 db 84 db 92 db 99 db 100 db 103 db
Onix RC200 89 db 87 db 98 db 98 db 101 db 101 db 103 db
Infinity Alpha 37C 75 db 77 db 87 db 87 db 91 db 90 db 93 db
For some reason, the result table does not show up very well in the post so I attached the screenshot of the excel table in this post along with the set up pics and two screen shoots of the Audyssey after calibration graphs and you can clearly see, according to Audyssey, that the center HMT1 showed absolutely no output below 150hz, compare to the my front speakers. However, based on my test, one can clearly see, the B&W is responded very well from 50hz and above just like other speakers. Then why the Audyssey would set the B&W HMT1 at 150hz and show no output below 150hz? When both the Onix is set correctly at 40hz and the small Infinity at 60hz. That was really puzzling me! Does anyone have any explanation beside the room interaction,the null zone or Audyssey suck? Well, at least I now know for sure that the B&W is working correctly and not a damage good!
Sorry for the long post! And thanks for reading and the response.
Sincerely,
BT
