Bought the Hsu STF-1 - Vibration normal?
I've spent fair bit of time looking for a small sub and ended with the HSU STF-1, details in another thread:
http://www.audioholics.com/forums/showthread.php?t=3312
After trying a few subs, HSU's STF-1 does produce cleaner and louder bass. However I can hear some kind of vibration noise/rattle coming from the driver/sub when played at high volume. It doesn't sound like loose part inside the sub cabinet, and I could only hear it when I played certain songs at fairly high level.
I spoke with Dr. Hsu, his explanation was that I shouldn't be playing at high level (max volume on sub), as the AMP was probably clipping and the sub was distorting, therefore generating secondary vibration not from the music. He said if I turn down the sub volume, and the vibration goes away, then that's the proof that the sub is not rattling but just clipping. He recommended I set the sub volume 9-10 o'clock position.
It seems to make sense, but 9-10 o'clock is rather low, considering max is at 5 o'clock position. Even when the sub vol. set at 10 o'clock position, the rattle goes away at the same receiver vol. (-45 dB ) but it comes back when the receiver volume is sufficiently high (-33 dB) .
i.e. Sub at Max , noise noticable at receiver vol. -45 dB
Sub at 10 o'clock , noise noticable at receiver vol. -33 dB .
I am using a Yamaha RX-V800 receiver (100W RMS/ch), but I also hear the noise when tested with my bedroom Yamanha micro-system system - (40W RMS/ch). at 1 o'clock vol.
I haven't heard this kind of noise on other subwoofers, so I wonder if this is a HSU specific design or I just have a bad unit. Based on what I told Dr. Hsu, he didn't think there is anything wrong with the sub, only that I am playing too loud. (then again, I could hear the noise when the sub vol. is set to 10 o'clock, which is less than half volume, and my Polk RM7600 satellite speakers were no where near distorting at receiver volume -33 dB)
For practical purpose this isn't a real issue as I don't normally turn the receiver volume that high ( typically only between -50 dB to -40 dB ) , and I could only hear the noise when I shut off the main speakers during testing.
Since I haven't had similar issue with other subs, I want to know if my unit is bad or it is the STF-1 design, or it's just plain normal.........
Appreciate you share your experience with any subs or HSU subs.
