replaced old speaker

jwhitbread
jwhitbread Posts: 3
edited June 2009 in Troubleshooting
I have an Infinity BU1. A very simple sub woofer. The speaker was torn so I replaced it with a Polk Audio 8 inch sub woofer speaker, the DB840.

It went right in. Both single coil speakers. All I get is a low hum.

I am using a high quality RCA cable. Nothing has changed since I took the old speaker out and put in the new Polk speaker.

Any idea why the low hum when powered and no real sound?
Post edited by jwhitbread on
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  • nguyendot
    nguyendot Posts: 3,594
    edited June 2009
    Might be a few things:
    Ground Loop, RCA is running near power, amplifier is going bad.

    Ground loop is easy, unplug the RCA and see if it goes away. Move the RCA's away form power

    Amp going bad - that's a harder one.
    Main Surround -
    Epson 8350 Projector/ Elite Screens 120" / Pioneer Elite SC-35 / Sunfire Signature / Focal Chorus 716s / Focal Chorus CC / Polk MC80 / Polk PSW150 sub

    Bedroom - Sharp Aquos 70" 650 / Pioneer SC-1222k / Polk RT-55 / Polk CS-250

    Den - Rotel RSP-1068 / Threshold CAS-2 / Boston VR-M60 / BDP-05FD
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  • jwhitbread
    jwhitbread Posts: 3
    edited June 2009
    If I unplug the RCA it doesn't make any noise.

    This sub is years old. I thought replacing the speaker would give me some more life. I'll look for an amp.

    I have all Klipsch otherwise. The RB 3 Series. I should look for the comparable sub and put this new Polk replacement in my van.
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  • lightman1
    lightman1 Posts: 10,788
    edited June 2009
    jwhitbread wrote: »
    and put this new Polk replacement in my van.
    Don't, please.
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  • nguyendot
    nguyendot Posts: 3,594
    edited June 2009
    The problem is coming from your RCA cable then, either its running too near a power cable or is introducing a ground loop.

    Google ground loop for some tips.

    Also, that sub is not designed for home theater use, it won't sound nearly as good as a suitable replacement.
    Main Surround -
    Epson 8350 Projector/ Elite Screens 120" / Pioneer Elite SC-35 / Sunfire Signature / Focal Chorus 716s / Focal Chorus CC / Polk MC80 / Polk PSW150 sub

    Bedroom - Sharp Aquos 70" 650 / Pioneer SC-1222k / Polk RT-55 / Polk CS-250

    Den - Rotel RSP-1068 / Threshold CAS-2 / Boston VR-M60 / BDP-05FD
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  • jwhitbread
    jwhitbread Posts: 3
    edited June 2009
    The speaker is as close to the one I have as I could find.

    nguyendot - Why do you say it is not a good application? What do you suggest? What is this speaker designed for?

    Lightman1 - It's an 8 inch sub woofer, why not use it where I can now that I own it?
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