udial and 4 destroyed tweeters later, what happened?

[simon5]

Hi,

My friend tested her brand new soundcard, a Creative X-Fi Elite Pro with udial.wav to see if that card passes the udial test. The card passed the test easily with success. Problem is, the tweeter in each Primus 150 bookshelf died. Only the tweeter in the center channel, a Primus C25 center channel, survived. She heard rattling during the test.

What happened? I'm really curious, seems impossible to me! Could someone analyze that sample to see if it's very problematic or unusual very high crest factor or something? Sorry I don't know if I can use the word crest factor in that way?

The test was done at moderate volume, -23 dB on her Pioneer amplifier which can deliver 100W per channel. According to the litterature, the Primus 150 bookshelf got a 4th order crossover (24 dB per octave) at 3.3 kHz. (Here is the specifications sheet)

http://www.infinitysystems.com/homea...es=PRI&cat=BFS

The udial test is there to test the IMD (intermodulation distortion)and poor SRC (resampling) of all Creative soundcards. Every Creative card fail the test at 44.1 kHz except the new X-Fi which got superior SRC algorithm based on a very powerful DSP (it's actually better than most SSRC (software based resampling)). The problem is only at 44.1 kHz, but that's the sampling frequency of 99% of music we listen to. (If you want to download it, please try a lower volume at first, I don't want to blow other people tweeters)

www.nitroware.net/files/udial.wav

You can see the bad IMD with IMD sweep tests, IMD is climbing with frequency. (Last graph in this link, this is for the Audigy 4 Pro, which is the less problematic card compared to previous generations)

http://www.3dss.com/reviews/Audigy4Pro/audigy4RMAA.html

Thank you very much for your help guys!

[Netlist]

I loaded the file into CoolEdit and looked at the statistics and Frequency curves.
This might help in finding an answer.

/Hugo

[Netlist]

Statistics:

[simon5]

Thank you very much Hugo.

Can you say your opinion on the subject?

BTW, did your soundcard pass the test?
You're supposed to hear only phone tones, nothing else.

[Netlist]

Simon,
I'm not an analyticus in FFT but the high peaks in the 20Khz region worry me a bit.
I hear much more than only dial tones. Soundcard is an old SBLive.

/Hugo

[Netlist]

Here's a pictures from the .wav itself.

[Netlist]

When I apply a 19.000Khz 6th order Low Pass filter I hear only the dial tones.
Strange .wav if you ask me, last time I had my ears tested I heard about 14Khz.

/Hugo

[simon5]

Yeah you're right that there's alot of peaking, but I mean at moderate volumes it shouldn't blow a tweeter.

Maybe she had already broken them before the test afterall...
That girl is rough with her audio gear, she keeps on hitting the thermal limiter on the Shiva subwoofer I built her. I should have used a Tumult or something.

[simon5]

Hugo, if you can use a powerful SSRC algorithm, resample it to 48 kHz or 96 kHz.

You'll then only hear dial tones.
It's a soundcard issue.

[Netlist]

Hmm. thanks, I will have a look if I can do that.
Still your 'four' tweeters problem is not solved.

/Hugo