Weird frequency response measurements.

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joaoveludo

joaoveludo

Member
Joined 2009
Hi.
Please, take take a look at these screenshots of ARC.

Can someone explain me that weird rise in high frequency on the HS80's?
I got them modded but they sound great to me... Could that be an indication of the NE5532's in oscillation? (they came with NJM4558's)

I took these measurements today, same room. I got both pairs of speakers working. (not at the same time )

HS80:
An externally hosted image should be here but it was not working when we last tested it.





Mission 763 (floorstanders):
An externally hosted image should be here but it was not working when we last tested it.




PS: I took the measurements with my diy mic based on the panasonic wm60 capsule with the linkwitz mod.

thanks.
 
wintermute

wintermute

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Joined 2003
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It looks to be the speakers (are they active), as the second measurement seems fine. I doubt that it is oscillation, as it is s steady rise from about 3K up to 20K of nearly 12db!! Oscillation (in the audio range) I would think would show up as hash or a spike at a particular frequency.

How does it sound after the correction is applied? It certainly looks like there is some sort of boost happening in the raw measurement as I really can't see how the tweeter would be 12db more efficient at 20K that and 3K with a pretty constant slope from start to finish.

Tony.
 
joaoveludo

joaoveludo

Member
Joined 2009
I know that hs80 are bright speakers but this seems ridiculous.
i really don't hear nothing abnormal besides yamaha's natural brightnes that it always had since day one.

If i apply the correction they sound completely muffled, cymbals almost disappear. Strange no?
I don't really use arc to correct the room. i'm trying to address that problem with the "do-some-acoustic-panels" way.
 
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wintermute

wintermute

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Joined 2003
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ok that changes things (a bit) . You should do a measurement of the Missions on axis with the tweeter. If possible take measurements of the HS80's with the mic in the same spot and the speaker in the same spot as the mission.

What was your measurement distance?

Tony.
 
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