Subwoofer signal measurement.

Discussion in 'Home Theater & Video' started by redrooster, Mar 8, 2018.

  1. redrooster

    redrooster who was that masked man?

    Messages:
    1,303
    Location:
    Mandurah Western Australia
    How can I measure the low frequency signal coming out of my Yamaha HTR-3063? I set my DMM to acmillivolts, it showed the signal for all the other speakers FL. FR, C, SL, SR, they were all OK. Im sure Ive set the menu for the subwoofer right, I have the S/W set to ""Yes"" all sound levels are turned up and all other speakers set to small, S/W crossover is set to 120hz and phase set to normal. I have my TV connected to the Yamaha with an optical cable to AV1.This is the first time Ive tried to use a subwoofer on the Yammy since new. Ive made sure to pick a 5.1 digital TV signal with a lot of low frequencies like music programs when testing for low freq signals. Am I doing something wrong testing for low frequencies or is the Yammy playing up?
     

     

    Please register to disable this ad.

  2. JoeESP9

    JoeESP9 ESL's & tubes since 83

    Messages:
    15,949
    Location:
    Philadelphia PA
    The TV in my bedroom is connected to a receiver (Yamaha) via a Toslink optical connection. The presence of a 5.1 signal from the TV is shown in the receivers display.

    Note: Many TV's, mine included will pass only two channel stereo from any input other than the internal tuner. Both of my 5.1 capable sources (Blu-ray player, Roku) are connected to my receiver and then from the receiver to an HDMI input on my TV. The receiver handles all audio.
     
  3. whoaru99

    whoaru99 Epic Member

    Messages:
    40,949
    Location:
    LoTL
    Normally you'd check/set the channel levels with a SPL meter, using the AVR's internal test/calibration signal.

    What am I missing that you're trying to do it so differently?
     
  4. redrooster

    redrooster who was that masked man?

    Messages:
    1,303
    Location:
    Mandurah Western Australia
    Ive misplaced my YPOA microphone. I downloaded the service manual, it says there should be 1volt on the receivers subwoofer output. I printed out the Set Menu Table, to go through every single step of it just to make sure everything is set-up right? Ive set up lots of these surround systems over the years and this is the only one that has had me bamboozled for so long. lol
     
  5. robgmn

    robgmn Super Member

    Messages:
    4,409
    Location:
    Twin Ports, MN
    So, you're trying to measure the voltage out and convert that to a dB level that the sub would produce?
     
  6. redrooster

    redrooster who was that masked man?

    Messages:
    1,303
    Location:
    Mandurah Western Australia
    No, Im just trying to see if there is any output. My DMM has a digital bar that fluctuates when a signals voltage is produced. The receiver is set-up by the manual, it didnt make any difference. Ive been getting an intermittent output for a few seconds every now and then so Ill take the lid off again and see if I can find anything? The subwoofer cable is fairly high quality, its brand new and has been checked for continuity. The signal must be appearing every now and then for a few seconds because the Accusound subwoofer relay clicks and the light goes from red to green. Ill post it here If I find whats wrong!
     

     

    Please register to disable this ad.

  7. whoaru99

    whoaru99 Epic Member

    Messages:
    40,949
    Location:
    LoTL
    Just run the test tone manually and set the levels using a SPL meter.

    1V isn't going to be there all the time, that's probably the level when playing near reference level with a hot source.

    I strongly suggest using the test tone and not overthinking this/making it harder than it is.
     
    plugto and redrooster like this.
  8. robgmn

    robgmn Super Member

    Messages:
    4,409
    Location:
    Twin Ports, MN
    And while keeping it simple, hook the sub up to a main channel pre-out to test and make sure the sub itself is working properly.
    Eliminate all unknowns and you can find and fix problems much more easily.
     
  9. redrooster

    redrooster who was that masked man?

    Messages:
    1,303
    Location:
    Mandurah Western Australia
    I measured the output of the S/W signal on the amplifier, its exactly the same reading as shorting the probes together, 0.3mv. The amp shows the S/W and all the speakers on the display and the source was a doof doof music channel. The S/W works when it gets the odd rare signal, the relay clicks the light changes from red to green and its loud for a second or two. So its got to be the amplifier playing up! I have the FL & FR speakers set to small but they are still playing bass through the woofers? (Bass Enhance was off!) I have the owners manual & the service manual for the amplifier so Ill check the s/m out and check the components out in the subwoofer circuit and see what comes up?
     
  10. JoeESP9

    JoeESP9 ESL's & tubes since 83

    Messages:
    15,949
    Location:
    Philadelphia PA
    IME many of the auto on circuits in powered subwoofers are not sensitive enough to come on when they should. Try setting the subwoofer to always on.
     
    stish likes this.
  11. redrooster

    redrooster who was that masked man?

    Messages:
    1,303
    Location:
    Mandurah Western Australia
    It is set to always on but theres is no signal coming from the amplifier. That was my origonal question because the amplifier was showing the subwoofer on its display but no LF? Im now trying to work out the self diagnostics on this amp to see whats going on?
     

     

    Please register to disable this ad.

  12. whoaru99

    whoaru99 Epic Member

    Messages:
    40,949
    Location:
    LoTL
    Ever gonna tell us what happens when you play the test tone in the receiver (which I presume is what you mean by amp)?
     
  13. redrooster

    redrooster who was that masked man?

    Messages:
    1,303
    Location:
    Mandurah Western Australia
    Ive already told you? There is no subwoofer signal coming from the receiver/amp!
     
  14. JoeESP9

    JoeESP9 ESL's & tubes since 83

    Messages:
    15,949
    Location:
    Philadelphia PA
    What settings are you using on the subwoofer?
     
  15. whoaru99

    whoaru99 Epic Member

    Messages:
    40,949
    Location:
    LoTL
    Dunno...have you?

    So far as I see it, it's only been direct reference to TV and music channel type stuff, not the test tone. And, previously you mentioned not having the YAPO mic, as if to say that was preventing you from doing it. :dunno:
     
    Last edited: Mar 14, 2018
  16. redrooster

    redrooster who was that masked man?

    Messages:
    1,303
    Location:
    Mandurah Western Australia
    Volume just under half way, crossover fully on and phase halfway.
     

     

    Please register to disable this ad.

  17. JoeESP9

    JoeESP9 ESL's & tubes since 83

    Messages:
    15,949
    Location:
    Philadelphia PA
    If you're going to use YPAO you should turn the level control and the crossover frequency control all the up. You'll be using the receiver for all level adjustments. I would also start with the phase at zero.

    Finding where you misplaced the microphone should be of primary concern. OTOH you could buy a replacement. Bear in mind that without the microphone to measure the test tones the receiver's speaker settings will revert to the most basic settings. IE: Two channel with no subwoofer.

    I'm curious. Do you hear the test tones when you run the auto calibration setup?
     
    Last edited: Mar 14, 2018
  18. redrooster

    redrooster who was that masked man?

    Messages:
    1,303
    Location:
    Mandurah Western Australia
    I tried the test tones manually yesterday or the day before? There was no LF signal. I read back through the post and I see Ive forgotten to mention it. Im picking up another subwoofer tomorrow to eliminate the s/w once and for all. Its 2.15am Im going to hit the sack.
     
  19. whoaru99

    whoaru99 Epic Member

    Messages:
    40,949
    Location:
    LoTL
    Thank you for the clarification. :thumbsup:
     
    redrooster likes this.
  20. JoeESP9

    JoeESP9 ESL's & tubes since 83

    Messages:
    15,949
    Location:
    Philadelphia PA
    If on your receiver you go into setup/speaker you'll find you can manually set and adjust all speaker parameters. I just tried this on my Yamaha receiver.

    This may be redundant. However it, needs to be asked. Do you have the receiver connected to your TV via HDMI? You need to see the receivers display to set the speaker levels and distances.
     
    Last edited: Mar 14, 2018

Share This Page