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PostPosted: Sat Nov 26, 2005 11:48 am 
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marielaure wrote:
MikeC I've done the analysis again and it's more like +23dB. See http://bingouille.ifrance.com/ (of course it's best viewing the jpg in 100% size; many browsers will badly resize the 1280*999 picture down, if so, find the no-resize option in your browser's picture display parameters, or simply download a copy of the 412 KB jpg file and view it at 100% size).
Also you can see on this graph that 450-750 Hz frequency range has similar amplitude to 1560 Hz pike; however human ear is particularly able to differentiate between two sound samples in the 200-2000 Hz frequency range so the 1560 Hz is easily audible apart from anything else.
I can extract the 1560 Hz pike sound from the rest of the frequency range (and keep amplitude unchanged) and post a small wav or mp3 to help identify what is a 1560 Hz sound.
Really hope your 7200.9 sample was bad // Seagate's nice reputation in hard disk noise aspects would hardly survive to such a bad thing as this 1.5kHz pike...

Anyway
many thanks for your site, reviews, forums; it gave me great help a few days ago to determine what hard drives (which I seem to consume like cherries) to buy; after examining all those great mp3 samples in a multitrack audio mixer (to easily compare and switch from one to another) I just ordered 4 Samsung SpinPoint P120 (250 GB ultraATA version) :wink:

OK, I see what you have done. But to say it is a +23 peak is still quite misleading. It is certainly not pereceived in this way. You are measuring it relative to the level of the freq immediately adjacent. The reality is that the overall perceived level is dominated by the broader peak at 600Hz, as well as the lower frq noise. It's the total area under the curve that determines total SPL. In this context it is easy to see that the 1.5kHz peak is a tiny portion of the total energy.

You also need to take into account the fact that the conditions in which the recording was made were designed to deliberately accentuate the peak artificially, as much as we could do -- just to illustrate what we're talking about.

Plewase don't take this info out of context!

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PostPosted: Sat Nov 26, 2005 12:53 pm 
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Agree with you on all these points. I investigated freq charts of the mp3 samples in order to decide what to buy; having read this 1.5kHz story I just was curious to locate it. That said, you can try to apply some sharp FFT filter to isolate the 1560Hz pike (using abrupt slopes and rejecting harmonics too) and compare the resulting sound with the source file; after that you'll clearly hear this pike within the whole sample. Of course the pike's SPL is low compared to total SPL but simply listening to the mp3 sample makes me wonder "what's this continuous beep" :wink:

This paragraph will be slightly off topic but I saw on Samsung's website that newest 300 & 400 GB are announced to be only slightly noisier than the P120; are these drives planned for review already ? would you bet they will be globally quieter than the 500 GB Seagate ?


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PostPosted: Sat Nov 26, 2005 1:05 pm 
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marielaure wrote:
Agree with you on all these points. I investigated freq charts of the mp3 samples in order to decide what to buy; having read this 1.5kHz story I just was curious to locate it. That said, you can try to apply some sharp FFT filter to isolate the 1560Hz pike (using abrupt slopes and rejecting harmonics too) and compare the resulting sound with the source file; after that you'll clearly hear this pike within the whole sample. Of course the pike's SPL is low compared to total SPL but simply listening to the mp3 sample makes me wonder "what's this continuous beep" :wink:

This paragraph will be slightly off topic but I saw on Samsung's website that newest 300 & 400 GB are announced to be only slightly noisier than the P120; are these drives planned for review already ? would you bet they will be globally quieter than the 500 GB Seagate ?

OK.... no bets, and yes, I am told some samples will come this way in Dec.

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PostPosted: Thu Apr 17, 2008 5:13 pm 
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question - what about other 7200.9 models? specifically the 250 GB?
[out of topic - is there a difference in the 7200.10 models? (specifically the 320 GB)?]
thanks a lot,
Dan.

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