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Topic: "Only few percents of FIDELITY" (Read 1835 times) previous topic - next topic - Topic derived from Educational Achieveme...
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"Only few percents of FIDELITY"

This is on the back of a conversation where the OP had claimed that a blind test was not required to correlate audibility with THD measurements because he read something by someone he deemed as an authority.  When the claim was rejected he decided to further this argument from authority by questioning the educational background of the people who contributed to the discussion.
@greynol

Could you explain why my subwoofer is under 1% of THD and at the same time totally unable to reproduce a complex audio signal in a range of only few percents of FIDELITY ?


Re: "Only few percents of FIDELITY"

Reply #1
I've split the above post from the original discussion because it was off-topic.

Could you explain why my subwoofer is under 1% of THD and at the same time totally unable to reproduce a complex audio signal in a range of only few percents of FIDELITY ?
I'm not sure I know what "few percents of fidelity" means.

Would you be able to provide data from controlled listening tests that demonstrate whatever problem it is that you're trying to describe is audible?

Re: "Only few percents of FIDELITY"

Reply #2
Quote
Could you explain why my subwoofer is under 1% of THD...
Put me down as "skeptical".   ;)  If it's an active (powered) subwoofer, that's probably just the amplifier  spec (when it's not clipping).

There are also frequency response non-linearities.  Possibly even resonance/ringing.   Room acoustics have a HUGE effect on frequency response and resonances. 

And, you can get rattling, buzzing, or port noise, etc.  

You could get intermodulation distortion (but I don't think that's a big problem with subwoofers).

It's also possible to overdrive the speaker or the amplifier, especially at very-low or subsonic frequencies (in which case you'll exceed the distortion spec).


P.S.
What subwoofer is this?

Re: "Only few percents of FIDELITY"

Reply #3
Could you explain why my subwoofer is under 1% of THD

Your subwoofer is not under 1% THD.  The spec sheet may claim that, but it is not true in practice.

Re: "Only few percents of FIDELITY"

Reply #4
I've got some loudspeakers that have great abilities in the bass domain and it is easy to perform a low THD measurements outdoor, and indoor.
On the figures 6 to 9 here : http://www.geocities.ws/kreskovs/Box-Q.html and especially the figures 15 and 16 here : http://www.geocities.ws/kreskovs/Box-Qa.html the input signal tracking is extremely poor, the output signal is not really in phase, wich mathematically tend to a very low number of statistical correspondance.
A Rice Kellogg loudspeaker is a sheet of paper (or someting else) putted in a box (if you want a punchy bass rendering) acuated by an electric motor... therfore it sounds like sheet of paper (or someting else) putted in a box (if you want a punchy bass rendering) acuated by an electric motor, trying to match the input signal to the output of acoustic energy in the air is a good place to start IMO.



Re: "Only few percents of FIDELITY"

Reply #7
Someone needs to break out the mannequin head microphones?
exhaleFLAC


Re: "Only few percents of FIDELITY"

Reply #9
I've got some loudspeakers that have great abilities in the bass domain and it is easy to perform a low THD measurements outdoor, and indoor.

What was the result of you doing this?

Re: "Only few percents of FIDELITY"

Reply #10
And the test data for audibility?
It is totally dependant of the Fs and Fs is different for each loudspeaker.
Again, we need proof of audibility.  Our rules are quite clear. Without proof we can't continue discussing this as if it is an actual problem.

Re: "Only few percents of FIDELITY"

Reply #11
I don't think he understands what John K as saying at all, or properties of any band limited system
Loudspeaker manufacturer



Re: "Only few percents of FIDELITY"

Reply #14
https://www.reddit.com/r/audiophile/comments/2rcv6s/audio_woo_checklist/
https://rationalwiki.org/wiki/Audio_woo

I'm here to improve my english.
That's a noble effort.  I'm having a difficult time figuring out whether you think you know what you're saying or you only think you know what you're saying.



Re: "Only few percents of FIDELITY"

Reply #17
could you explain what is fishing 101 or 102 please ?



Re: "Only few percents of FIDELITY"

Reply #20
Sorry, i'm totally hermetic to the geek culture, i've recentely forced myself to read few pages of a manga and watch a episode of "big bang theory" but i still need a translator  :(

Re: "Only few percents of FIDELITY"

Reply #21
Sorry, i'm totally hermetic to the geek culture,
That doesn't seem consistent with your persona over at diyaudio.  :o

 

Re: "Only few percents of FIDELITY"

Reply #22
Just saying, when you make loud bass sound waves, "perfect" woofers aren't enough, you need to make sure that no objects in your home resonate with it. A lot of metal/plastic/glass/etc. objects may add "distortion" because they literally jump and hit other hard surfaces, and they need to be fixed in place or dampened somehow. So if you hear a distortion, check if it actually comes from the subwoofer or it's something jumping in your room.
some ANC'd headphones + AutoEq-based impulse + Meier Crossfeed (30%)

 
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