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1 Ohm 15 Inch Speaker?

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  • 1 Ohm 15 Inch Speaker?

    I am reading 0.8 ohms DC resistance on this speaker.

    Is this a 1 ohm speaker? I an thinking the last 4 characters on the stamp "001R" may imply so?

    Speakers works and was pulled from a Peavey MAX 115 combo.

    Anyone know the speaker brand?

    Thank you

    Click image for larger version  Name:	IMG_20231115_121641600.jpg Views:	0 Size:	3.14 MB ID:	989205 Click image for larger version  Name:	IMG_20231115_122128933.jpg Views:	0 Size:	523.0 KB ID:	989204 Click image for larger version  Name:	IMG_20230819_113350378_HDR.jpg Views:	0 Size:	2.54 MB ID:	989206

  • #2
    - Bass guitar combo amplifier, TransTube amp emulator
    Power: 60W RMS, 4 ohms, 15" speaker​


    • #3
      1 ohm speaker would be most commonly found in car audio for subwoofers. If this is one I don't think the Peavey amp would have been happy driving a 1 ohm load at higher power levels.
      Does it move properly? Sometimes a partially burnt coil will still give sound.
      Originally posted by Enzo
      I have a sign in my shop that says, "Never think up reasons not to check something."


      • #4
        Meter calibrated, battery fresh?
        Measure a 3.3R resistor for reference.
        - Own Opinions Only -


        • #5
          My wall plugged DMM is good,. I use it daily and other readings are good.

          I had problems with this amp. Cutting in and out, dead spots on the pots, and then a constant ticking noise, and the last time tested there was a burnt smell but I could not see any burnt area. With all the issues it was not worth fixing, IMO.

          So now I am trying to use parts and started with the 15" speaker as I needed a 4 ohm for my Acoustic Model 116. This speaker sounded fine when last used. I was surprised at the low DCR. Just checked for cone movement and it is stuck and stiff.

          The tweeter reads open.

          Running out of parts to salvage here.

          Thank you. MarkO


          • #6
            That burning smell was probably the voice coil of the speaker. It's almost certainly shorted if you measure .8 ohms DCR. Attempting to use it will damage the amp.
            "I took a photo of my ohm meter... It didn't help." Enzo 8/20/22


            • #7
              I think that amp uses the TDA8954 power amp IC, which is rated for a min load of 4 ohms.


              • #8
                Impedance and DC resistance are two completely different things. It would be very unusual to find a good loudspeaker with a < 1.8 OHMS DC resisrance across the coil, even for automotive use and from your descrition, I would guess that the voice coil has been cooked.

                The average 8 Ohm voicecoil of reasonable quality is usually around 5 - 6 Ohms DC resistance but when fed with a signal of say 1kHZ, the AC voltage drop across a known value resistor will allow you to calculate the impedance. If the frequency level is kept static but the frequency is adjusted, we can plot the useful frequency response as when the frequency exceeds, the either higher or lower value, the voltage across the resistor will increase and indeed decrease, showing us the optimum frequencies are exceeded or have low output troughs in the graph. (To put it in layman's terms). Peaks and troughs, will also be visible when plotting and the optimal louspeaker will show almost a straight line on the graph, a poorer quality or different use sounder will show different peaks and troughs.
                Assuming the signal source is of a low enough impedance itself, that is.

                A DC resistance check will tell you if the voice coil is short circuit or open circuit, it won't tell you if a few turns overheated and have shorted out. I use a small battery to check for sound on a loudspeaker, that will tell me straight away whether it works and what the polarity is.
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                • #9
                  Originally posted by misterc57 View Post

                  The tweeter reads open.
                  That tweeter looks like a piezo. It can't even be tested with a multimeter. Just an generator.