Problems with my SDA 2's?

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jacobmeyerammo
jacobmeyerammo Posts: 53
in Speakers
Hi everyone. New to the forum and have a question about a well taken care of pair of SDA 2's i just picked up. I believe they are 2 b's, two drivers and one tweeter. When i play them they seem to get stressed and one side will fade out. After turning down the source it comes back. Any suggestions as to what might be the problem? I am using a Onkyo 7.1 receiver to power them. 3kmcnp24t2i5.jpg
7.me0yxl6jb66p.jpg
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  • Gardenstater
    Gardenstater Posts: 4,184
    edited January 2020 Answer ✓
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    I looked at your manual and it says: "CAUTION: SPEAKER IMPEDANCE 6 OHMS MIN. / SPEAKER"

    https://www.hifiengine.com/manual_library/onkyo/tx-sr701.shtml

    owcxeien0u5s.png
    jacobmeyerammo wrote: »
    Any suggestions on what to power them with? Power level ect on a budget...

    I'm not at all knowledgeable about 7.1 A/V receivers. Perhaps others will weigh in....
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
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Answers

  • F1nut
    F1nut Posts: 49,798
    edited January 2020
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    Those are 2A's. You're tripping the polyswitch (small mustard colored device), which could be due to it being hypersensitive or you're AVR is clipping.
    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

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  • jacobmeyerammo
    jacobmeyerammo Posts: 53
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    So this is a device protect? How do i tell if its the polyswitch or my AVR?
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  • pitdogg2
    pitdogg2 Posts: 24,575
    edited January 2020
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    Symptoms you describe lead to the polyswitch being wore out from being tripped tooany times.
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  • jacobmeyerammo
    jacobmeyerammo Posts: 53
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    Right....so I've only had these few days. Do i just assume the switch is bad? Or do i assume the receiver is clipping? How can I test?
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  • Gardenstater
    Gardenstater Posts: 4,184
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    I think you could just put a short alligator clip jumper around the polyswitch to find out if it is the problem.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
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  • jacobmeyerammo
    jacobmeyerammo Posts: 53
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    Wouldn't that just open the door to speaker damage?
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  • Gardenstater
    Gardenstater Posts: 4,184
    edited January 2020
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    Perhaps, but you asked about how to test. You can then choose to purchase a new polyswitch or to revert to a glass fuse with a small resistor to compensate for the missing polyswitch. Others may weigh in....

    You didn't say, but what dB levels or power output levels from your receiver are you encountering the problem at?
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
    · Share on FacebookShare on Twitter
  • jacobmeyerammo
    jacobmeyerammo Posts: 53
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    So they sound great all the way to about 1/3 volume control on the receiver. At about halfway to a little above half is when they cut out. I do not hear any distortion or ill quality but im no pro either.
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  • jacobmeyerammo
    jacobmeyerammo Posts: 53
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    I will have to check but i believe the receiver to be about 100 wpc
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  • Gardenstater
    Gardenstater Posts: 4,184
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    What Onkyo receiver model#? How much power rating into different impedance loads?
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
    · Share on FacebookShare on Twitter
  • jacobmeyerammo
    jacobmeyerammo Posts: 53
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    Im currently at work and will check the model number as soon as i get home. I really appreciate all the help.
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  • jacobmeyerammo
    jacobmeyerammo Posts: 53
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    So i looked it up..r4pnf1rz132e.png
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  • pitdogg2
    pitdogg2 Posts: 24,575
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    Those speakers start out at a 4ohm load and drop to the low 3 ohm area. They are very hard on receivers if you plan on listening to them at upper volume. They really need a amp with current. Trust me your receiver is straining hard with those.
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  • jacobmeyerammo
    jacobmeyerammo Posts: 53
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    Any suggestions on what to power them with? Power level ect on a budget...
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  • jacobmeyerammo
    jacobmeyerammo Posts: 53
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    I had no idea these speakers dipped so low. I guess i fugured they would be 8 ohm because all my other speakers have been. I will do some looking and you are definitely right these things will kill that receiver. Thank you again.
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  • Gardenstater
    Gardenstater Posts: 4,184
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    I haven't found the impedance curve yet but I found this, and it does indeed dip down to 3.5 Ohms at one point:

    http://www.hifi-classic.net/review/polk-audio-sda-2a-181.html

    "We measured the impedance on one speaker with the interconnect cable installed but the signal terminals of the other speaker shorted (which results in the lowest possible impedance). The minimum impedance, about 3.5 ohms, was reached at 100 to 130 Hz, and maximum figures of 12 to 15 ohms occurred at 20, 55, and 1,000 Hz. Over most of the middle- and high-frequency range the impedance was about 10 ohms. With an input of 2.83 volts of pink noise, the SDA-2A produced a sound-pressure level (SPL) of 88 dB at a distance of 1 meter."
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
    · Share on FacebookShare on Twitter
  • Gardenstater
    Gardenstater Posts: 4,184
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    Yep clearly your receiver is not up to the task. From the manual for your SDA 2A:

    https://www.hifiengine.com/manual_library/polk-audio/sda-2.shtml

    zfm18lqsalos.png

    And Polk calls it a 5 Ohm "D.C. Resistance" speaker:

    rhg5w9z987uo.png

    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    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
    · Share on FacebookShare on Twitter
  • aprazer402
    aprazer402 Posts: 3,097
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    Welcome to the Polk Forum! Very good advice from the others. The 2A's are 3-4 ohm and require more than your Onyko provides. I enjoy my 2A's! ;)cs186ofb73vq.jpg
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  • pitdogg2
    pitdogg2 Posts: 24,575
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    aprazer402 wrote: »
    Welcome to the Polk Forum! Very good advice from the others. The 2A's are 3-4 ohm and require more than your Onyko provides. I enjoy my 2A's! ;)cs186ofb73vq.jpg

    What SDA 2a ?
    That is a heck of a danvenport you have.
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  • aprazer402
    aprazer402 Posts: 3,097
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    I can only wish! ;)
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  • TennMan
    TennMan Posts: 1,264
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    I think that is the nicest couch cover I have ever seen.
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  • Hermitism
    Hermitism Posts: 4,205
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