Monitor 7B Question: - "Resonance" on this song track
odcics2
Posts: 331
Here's a song that I notice has some extra "resonance", at about the 1:55 second mark.
It sounds louder, a 'bump' in the volume best describes it.
McCartney - Hot as Sun / Glasses
https://www.youtube.com/watch?v=diL3AnFc3SM
"Glasses" is actually McCartney playing a set of drinking glasses...
For reference, I have another pair speakers that don't have this issue, at all.
I'm trying to figure where my problem could be on my 7B speakers.
Midwoofer? tweeter? crossover? (all parts are original)
I don't notice any other anomalies on any other recordings I play on these 7Bs.
Thanks for any insight you guys can offer.
It sounds louder, a 'bump' in the volume best describes it.
McCartney - Hot as Sun / Glasses
https://www.youtube.com/watch?v=diL3AnFc3SM"Glasses" is actually McCartney playing a set of drinking glasses...
For reference, I have another pair speakers that don't have this issue, at all.
I'm trying to figure where my problem could be on my 7B speakers.
Midwoofer? tweeter? crossover? (all parts are original)
I don't notice any other anomalies on any other recordings I play on these 7Bs.
Thanks for any insight you guys can offer.
Comments
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Obviously, it's in the recording. There's no problem with your speakers.Political Correctness'.........defined
"A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."
President of Club Polk -
I didn't hear anything unusual on mine. The resonant peaks were at 473 Hz and 1.1 kHz if that helps you at all.George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
I have other speakers that don’t have the same anomaly, so it’s this pair of 7B specific.
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Gardenstater wrote: »I didn't hear anything unusual on mine. The resonant peaks were at 473 Hz and 1.1 kHz if that helps you at all.
I have an extra pair of midwoofers that I could swap into my 7Bs.
Any possibility that it’s a cabinet resonance at those frequencies, exciting by those two peaks? -
If you plug the internal dimensions of the 7B into a standing wave calculator, you get that the main trouble spot is around 900 Hz. I did the testing again and actually did see peaks right around there, but they oscillate in and out.
You don't have the BH5 behind the midwoofers, and you don't have the Armacell inside the basket so you could be getting an exaggerated effect from that as it passes through the cone diaphragm and bounces back and forth inside the basket, that I am not getting with mine. Also, do you have the roll of polyfill tucked up behind the midwoofer and tweeter?
You also could be getting ringing of the stamped steel basket. You don't have Dynamat or other CLD material on the basket, correct?George / NJ
Polk 7B main speakers, std. mods+ (1979, orig owner)
Martin Logan Dynamo sub w/6ft 14awg Power Cord
Onkyo A-8017 integrated
Logitech Squeezebox Touch Streamer w/EDO applet
iFi nano iDSD DAC
iPurifier3
iDefender w/ iPower PS
Custom Steve Wilson 1m UPOCC Interconnect
iFi Mercury 0.5m OFHC continuous cast copper USB cable
Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
Custom Vibration Isolation Speaker Stands and Sub Platform -
I’ll double check the polyfill.
It was located correctly when I checked them out after I bought them.
The MW and passive have strips of a dynamat like material. I don’t remember the brand offhand -
I have No-Rez on order and will do a dowel brace, front to rear.
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Smart move on the dowel brace. I'd also add to double-check the tightness of the tweeter magnet screws.Don't take experimental gene therapies from known eugenicists.
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Will do.
