Polk L800 speakers - SPL below 100 Hz dropped about 6db.

Options
1235

Comments

  • mhardy6647
    mhardy6647 Posts: 33,046
    edited November 2022
    Options
    6sttqco8eo44.png

    So, this is really interesting.
    It's not the absolute level that matters sonically -- it's the level relative to the midrange output.
    The Polk exhibits a flat response in the region of 60 to 200 Hz. The Focal shows a bump in LF response (relative to the midrange) of about 15 dB at a little over 100 Hz relative to 1kHz (ca. 12 dB relative to 400 Hz). This looks like the classic, underdamped "boom box" alignment, much beloved in cheap car stereo. This is a recipe for loose, one-note midbass -- which is not bass reproduction.

    Both loudspeakers display substantial rolloff starting at about 60 Hz.
    The quality of LF reproduction, based on this comparison, should be audibly much more accurate from the Polk relative to the Focal.

    Both loudspeakers show that suckout, too, although it is more pronounced in the Polk. Oddly it's now at 450 Hz (which would play havoc with vocals). When we first met it, it was ca. 100 Hz. Why is this?

    2ekle81kqm73.png

    This whole thread illustrates the pitfalls of testing loudspeakers, especially bass reproduction, in a reverberant environment. The OP might want to lug an L800 outside and test in that quasi-anechoic environment, or acquire a Klippel loudspeaker analysis system.


    · Share on FacebookShare on Twitter
  • Gardenstater
    Gardenstater Posts: 4,187
    edited November 2022
    Options
    mhardy6647 wrote: »
    [img]https://us.v- Both loudspeakers show that suckout, too, although it is more pronounced in the Polk. Oddly it's now at 450 Hz (which would play havoc with vocals). When we first met it, it was ca. 100 Hz. Why is this?[/img]


    Since this is nearfield measurements only 2cm from the cone of the woofers, it is severely off axis for the midrange speakers. I don't think this graph should even be looked at above the crossover points of the woofers.

    We saw in his nearfield measurements of the Polk where he did all 4 woofers (2L and 2R) that the ones nearer the midwoofs didn't have that suck out you speak of. It isn't clear which woofs he is showing in the above tests. I "think" it may be the top woof of the Focal compared with the bottom woof of the Polks.

    I see now that caffeine has kicked in that the ports are on the front of Focal and we know they are on the bottom of Polks. This may effect things for comparing the two nearfield.
    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
  • mhardy6647
    mhardy6647 Posts: 33,046
    edited November 2022
    Options
    Good points. If we're really basically looking at woofer response, the Polk looks much better (much flatter).

    dosvu4n2h9x4.png

    · Share on FacebookShare on Twitter
  • Gardenstater
    Gardenstater Posts: 4,187
    edited November 2022
    Options
    Another difference between the 2 speakers is that I believe the Focal has 3 woofers and the Polks have 2. Focal is crossed over at 260 Hz and Polk is at 370 Hz. Getting back to his nearfield test of all 4 Polk woofers, how can we explain this suckout when crossover is at 370? Which woofer is it that has the suckout, is it the upper or lower? Are the woofers paralleled with each other in the schematic or is this indication of some crossover component damage that occurred in both speakers (amazingly

    Below is nearfield measurement of four woofers:
    rdibr38216lb.png

    PS: What I believe is missing here is that the ports need to be measured in the nearfield as well to get some sort of composite bass response that is more true or accurate.
    Post edited by Gardenstater on
    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
  • Emlyn
    Emlyn Posts: 4,372
    Options
    I think a better way to test to see if a speaker drops volume when it gets warmed up or hot is to just sit in the regular listening spot with an SPL meter for a while and listen to some tunes on repeat. Maybe have a beer or two.
    · Share on FacebookShare on Twitter
  • Gardenstater
    Gardenstater Posts: 4,187
    edited November 2022
    Options
    mhardy6647 wrote: »
    Good points. If we're really basically looking at woofer response, the Polk looks much better (much flatter).

    dosvu4n2h9x4.png

    I'm seeing about 5dB variance on the Focal, from the peak to the crossover point of 260 Hz. On the Polk I see about 10dB between peak and the crossover point of 370 Hz.

    That could very well be because something is damaged in the Polk crossover however.
    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
  • audioluvr
    audioluvr Posts: 5,437
    edited November 2022
    Options
    Jarod888 wrote: »
    Gardenstater wrote: »
    Let's see the test results with the Focal speakers and same inputs 😉

    Thanks, just tested Focal for you. The microphone is about 2cm from the woofer of Focal 936. just like how I test Polk L800.
    You can see the bass response of Focal 936 is much better, that is just a 6.5 inch woofer.

    2iihlfc64fq4.jpg
    syahgvh8i01o.jpg

    Those Focals have a terribly bloated bass response!

    Edit: Just noticed @Clipdat already mentioned that.
    Gustard X26 Pro DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Polk SDA 1C's modded / 1000Va Dreadnaught
    Wireworld Silver Eclipse IC's and speaker cables
    Harman Kardon T65C w/Grado Gold. (Don't laugh. It sounds great!)

    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January. by Dr. Sardonicus
    · Share on FacebookShare on Twitter
  • Gardenstater
    Gardenstater Posts: 4,187
    Options
    Nearfield measurements are very revealing, as done by Stereophile's John Atkinson for the Focal 936. Note he did each of the 3 woofers and the front port and bottom port. Does the middle woofer look all that different from the OP's measurement? I'll be looking for the same measurements for the L800 and post them if I can find it. Also, the reviewer didn't find the bass to be bloated but did feel it had nice extension. The calculated summation (not shown), which can always be flawed for technical reasons, did show a bit of bloat perhaps. Does it seem like the OP's equipment is flawed I guess is one of the questions?

    y4mizcuak2c1.jpg




    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
  • Clipdat
    Clipdat Posts: 12,608
    Options
    giphy.gif
    · Share on FacebookShare on Twitter
  • skipshot12
    skipshot12 Posts: 1,002
    Options
    ^ Dang it…..
    I was hoping this was a notice that the OP was reporting back that the issue was found.
    · Share on FacebookShare on Twitter
  • Clipdat
    Clipdat Posts: 12,608
    Options
    Hopefully he doesn't leave us hanging, but would not be surprised if we never hear from him again.
    · Share on FacebookShare on Twitter
  • pitdogg2
    pitdogg2 Posts: 24,579
    Options
    Bullies








    😜
    · Share on FacebookShare on Twitter
  • txcoastal1
    txcoastal1 Posts: 13,132
    Options
    pitdogg2 wrote: »
    Bullies

    😜

    You airhole :p
    2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
    Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
    Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
    Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC

    erat interfectorem cesar et **** dictatorem dicere a
    · Share on FacebookShare on Twitter
  • pitdogg2
    pitdogg2 Posts: 24,579
    Options
    txcoastal1 wrote: »
    pitdogg2 wrote: »
    Bullies

    😜

    You airhole :p

    I'm NOT offended!!!

    😎
    · Share on FacebookShare on Twitter
  • Clipdat
    Clipdat Posts: 12,608
    Options
    Hey guys what's going on in this dead L800 measurements thread?
    · Share on FacebookShare on Twitter
  • nooshinjohn
    nooshinjohn Posts: 25,100
    Options
    I think he ran out of stuff to measure and went back to his crack pipe...
    The Gear... Carver "Statement" Mono-blocks, Mcintosh C2300 Arcam AVR20, Oppo UDP-203 4K Blu-ray player, Sony XBR70x850B 4k, Polk Audio Legend L800 with height modules, L400 Center Channel Polk audio AB800 "in-wall" surrounds. Marantz MM7025 stereo amp. Simaudio Moon 680d DSD

    “When once a Republic is corrupted, there is no possibility of remedying any of the growing evils but by removing the corruption and restoring its lost principles; every other correction is either useless or a new evil.”— Thomas Jefferson
    · Share on FacebookShare on Twitter
  • msg
    msg Posts: 9,462
    Options
    Ah, yeah, that'll entice him to share the findings.
    I disabled signatures.
    · Share on FacebookShare on Twitter
  • Clipdat
    Clipdat Posts: 12,608
    Options
    Hey if you can't stand the heat, get out of the kitchen!
    · Share on FacebookShare on Twitter
  • halo71
    halo71 Posts: 4,572
    Options
    At least he wasn't whining about his 15TL's. lol
    --Gary--
    Onkyo Integra M504, Bottlehead Foreplay III, Denon SACD, Thiel CS2.3, NHT VT-2, VT-3 and Evolution T6, Infinity RSIIIa, SDA1C and a few dozen other speakers around the house I change in and out.
    · Share on FacebookShare on Twitter
  • msg
    msg Posts: 9,462
    Options
    Chased him away you hosers. nicely done.
    I can't decide if I'm being sarcastic or not.
    I disabled signatures.
    · Share on FacebookShare on Twitter
  • nooshinjohn
    nooshinjohn Posts: 25,100
    Options
    50 bucks to your favorite charity that he was never coming back in the first place...
    The Gear... Carver "Statement" Mono-blocks, Mcintosh C2300 Arcam AVR20, Oppo UDP-203 4K Blu-ray player, Sony XBR70x850B 4k, Polk Audio Legend L800 with height modules, L400 Center Channel Polk audio AB800 "in-wall" surrounds. Marantz MM7025 stereo amp. Simaudio Moon 680d DSD

    “When once a Republic is corrupted, there is no possibility of remedying any of the growing evils but by removing the corruption and restoring its lost principles; every other correction is either useless or a new evil.”— Thomas Jefferson
    · Share on FacebookShare on Twitter
  • Jarod888
    Jarod888 Posts: 61
    edited November 2022
    Options
    Hi Everyone, I fixed this issue on 7th of November 2022 by myself.

    I bought a new Umik-1 microphone, it turns out my old Umik-1 microphone was not working properly sometimes, completely unpredictable.

    Thanks very much for all the help.

    Post edited by Jarod888 on
    · Share on FacebookShare on Twitter
  • Jarod888
    Jarod888 Posts: 61
    edited November 2022
    Options
    My old UMIK-1 microphone sometimes work properly sometimes not, that's why the test results keep changing.
    miniDSP support denied it's a microphone issue, however I proved that it was the microphone by buying a new UMIK-1 microphone and compare it with the old one.

    Very disappointed with miniDSP support and microphone build quality.
    · Share on FacebookShare on Twitter
  • Jarod888
    Jarod888 Posts: 61
    Options
    mhardy6647 wrote: »
    6sttqco8eo44.png

    So, this is really interesting.
    It's not the absolute level that matters sonically -- it's the level relative to the midrange output.
    The Polk exhibits a flat response in the region of 60 to 200 Hz. The Focal shows a bump in LF response (relative to the midrange) of about 15 dB at a little over 100 Hz relative to 1kHz (ca. 12 dB relative to 400 Hz). This looks like the classic, underdamped "boom box" alignment, much beloved in cheap car stereo. This is a recipe for loose, one-note midbass -- which is not bass reproduction.

    Both loudspeakers display substantial rolloff starting at about 60 Hz.
    The quality of LF reproduction, based on this comparison, should be audibly much more accurate from the Polk relative to the Focal.

    Both loudspeakers show that suckout, too, although it is more pronounced in the Polk. Oddly it's now at 450 Hz (which would play havoc with vocals). When we first met it, it was ca. 100 Hz. Why is this?

    2ekle81kqm73.png

    This whole thread illustrates the pitfalls of testing loudspeakers, especially bass reproduction, in a reverberant environment. The OP might want to lug an L800 outside and test in that quasi-anechoic environment, or acquire a Klippel loudspeaker analysis system.



    Thanks, the microphone used for testing was not working properly sometimes.
    I've bought a new microphone. here is the test result of left speaker, please note it's not a nearfield test.
    gjyon2i96hv8.jpg
    · Share on FacebookShare on Twitter
  • pitdogg2
    pitdogg2 Posts: 24,579
    Options
    Rotflmao!
    Try just using your ears skeeter!
    · Share on FacebookShare on Twitter
  • Jarod888
    Jarod888 Posts: 61
    edited November 2022
    Options
    pitdogg2 wrote: »
    Rotflmao!
    Try just using your ears skeeter!

    Sometimes the bass sounds weaker, maybe it's my ears.
    · Share on FacebookShare on Twitter
  • Gardenstater
    Gardenstater Posts: 4,187
    Options
    So. Any idea why you experienced a sudden loss of bass (audibly) while in the middle of them playing? Was that just imagination?

    Glad you are getting good bass now and that you got back to us.
    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
  • txcoastal1
    txcoastal1 Posts: 13,132
    Options
    Jarod888 wrote: »
    pitdogg2 wrote: »
    Rotflmao!
    Try just using your ears skeeter!

    Sometimes the bass sounds weaker, maybe it's my ears.

    Get you a nice sub or 2. You are going to end up trying to push those speakers and blow something.
    2-channel: Modwright KWI-200 Integrated, Dynaudio C1-II Signatures
    Desktop rig: LSi7, Polk 110sub, Dayens Ampino amp, W4S DAC/pre, Sonos, JRiver
    Gear on standby: Melody 101 tube pre, Unison Research Simply Italy Integrated
    Gone to new homes: (Matt Polk's)Threshold Stasis SA12e monoblocks, Pass XA30.5 amp, Usher MD2 speakers, Dynaudio C4 platinum speakers, Modwright LS100 (voltz), Simaudio 780D DAC

    erat interfectorem cesar et **** dictatorem dicere a
    · Share on FacebookShare on Twitter
  • Jarod888
    Jarod888 Posts: 61
    edited November 2022
    Options
    Gardenstater wrote: »
    So. Any idea why you experienced a sudden loss of bass (audibly) while in the middle of them playing? Was that just imagination?

    Glad you are getting good bass now and that you got back to us.

    It could be I moved, or the song, or imagination, or all together.

    Most likely I moved a little bit, and then tested the speaker and the microphone didn't work properly, coincidence

    Since the test reslut showed the weak bass, then I started feeling the bass was not right.
    · Share on FacebookShare on Twitter
  • Jarod888
    Jarod888 Posts: 61
    Options

    txcoastal1 wrote: »
    Jarod888 wrote: »
    pitdogg2 wrote: »
    Rotflmao!
    Try just using your ears skeeter!

    Sometimes the bass sounds weaker, maybe it's my ears.

    Get you a nice sub or 2. You are going to end up trying to push those speakers and blow something.

    Thanks, I will consider adding sub.
    · Share on FacebookShare on Twitter