k
Date: Tue Jul 27, 2010 6:14 pm ((PDT))
oops, sorry folks...that was meant to go privately to Dan Dugan...please ig=
nore!
Apologies,
Vlad
Wolodymyr Smishkewych
wolodymyrsmishkewych.com
On 27 Jul 2010, at 21:12, Wolodymyr Smishkewych wrote:
> Hi Dan,
>
> I'm leaving Bloomington on Saturday and only will be in the country until=
the 9th August, so I figured I should touch base about where the Uher and =
Nagra stand. I recall you writing that the Nagra was done, and that you had=
already done 1 hr on the Uher. I don't know if you've proceeded with more =
work or not, but I wanted to make sure there was enough lead time for me to=
receive the machines from you.
>
> Also, I can pay this first invoice you've sent now, or would you prefer I=
pay both the Nagra and Uher service together? And, would you like me to pa=
y by check, paypal, or CC? I can call it in tomorrow if that is your prefer=
ence.
>
> Thanks so much,
> Vlad
>
>
> Wolodymyr Smishkewych
> wolodymyrsmishkewych.com
>
>
>
>
> On 27 Jul 2010, at 18:43, Dan Dugan wrote:
>
>>>>> Here's a blind comparison movie created from the results of a moving
>>>>> pink noise test that is hopefully very similar to what Dan suggested.
>>>>> The (3mb .zip) download link is at the bottom of the blog post here:
>>>>> <http://tinyurl.com/2egg33s>http://tinyurl.com/2egg33s Play it
>>>> with QuickTime or a
>>>>> QuickTime-compatible player on your computer.
>>>>
>>>> Very nice, thank you, Rob.
>>>>
>>>> I've posted a Spectrafoo sonogram of the MP3 at:
>>>>
>>>> <http://www.dandugan.com/downloads/Miscellany/20100726_BoundaryCombFil=
tering.png>http://www.dandugan.com/downloads/Miscellany/20100726_BoundaryCo=
mbFiltering.png
>>>>
>>>> and another with higher gain trying to show the highest frequencies be=
tter
>>>>
>>>> <http://www.dandugan.com/downloads/Miscellany/20100726_BoundaryCombFil=
tering_2.png>http://www.dandugan.com/downloads/Miscellany/20100726_Boundary=
CombFiltering_2.png
>>>>
>>>> The most audible effects I hear are a descending tonal effect in the
>>>> mid-range and the directivity of the mics at high frequencies (HF
>>>> comes up as pan comes on axis). Both happen on all three mountings.
>>>> I don't understand the source of the mid-range effect.
>>>>
>>>> Comb filtering effects at the top end that were my concern when I
>>>> proposed the test are more subtle than I expected. I found it useful
>>>> to high-pass the playback way up like 5k-8K to eliminate the
>>>> distractions of the lower effects.
>>>>
>>>> -Dan
>>>>
>>>
>>> Hi Dan--
>>>
>>> Both files I posted are full res (movie's soundtrack 16/48K and .wav
>>> 24/48K). So no mp3 artifacts should be involved.'
>>
>> I was mistaken in saying MP3.
>>
>>> I'm noticing a dropping chord with a fundamental around 407 Hz that
>>> changes to about 347 Hz in all samples.
>>
>> Exactly.
>>
>>> It sounds a bit like a
>>> Doppler effect but that doesn't seem possible as the speaker isn't
>>> getting closer and the velocities are so low. Could it be something
>>> like a difference tone created by sliding pitch changes high in the
>>> spectrum? Yet, that would be psychoacoustic and there may be a faint
>>> trace of the 407- 347 Hz drop in the sonograms.
>>
>> I don't think so. Any reflective surface other than the ground nearby? E=
ffect of the ground should be constant unless you actually changed elevatio=
n as you moved...comb filter effects are very sensitive to small difference=
s.
>>
>>> Can one tell if the steep, downward sloped bands in the last 2/3rds
>>> of the A samples and the less steep upwards sloped bands in the last
>>> half of C samples is comb filtering?
>>
>> That's how I interpret them.
>>
>>> My older ears are pressed to
>>> detect this HF content . Rob D.
>>
>> Me, too, after high-passing 12dB/oct at 8K I hear a little something jus=
t at the end of #1, and swishing in no. 3.
>>
>> -Dan
>>
>>
>
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>
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>
> ------------------------------------
>
> "While a picture is worth a thousand words, a
> sound is worth a thousand pictures." R. Murray Schafer via Bernie Krause
> Yahoo! Groups Links
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