Free Shipping on All Orders 1-866-764-1801

Vist our Online Store
+ Reply to Thread
Results 1 to 22 of 22
  1. #1

    Member Sales Rating: (0)

    Join Date
    Nov 2004
    Posts
    5

    Default polk mm12 freq response question

    I had a bass test cd and the mm12 was poinding... (just to clarify, the sub is broken in properly)

    i realized i had the subsonic filter on, 20hz-50hz was off.

    Heres a little of my situation, I am running the sub off speaker wire line-out-converted to RCA, going to a RF amp and to the sub. I'm not sure on the voltage but the L-o-c is supposed to drop it from 20 to 5-8. Anyhow, its not RCA setup because my car has fiber optics and you basically cant do it...

    Will the sub be fine playing 20hz to 50hz? or is it safer to just leave it off?

  2. #2

    Member Sales Rating: (0)

    Join Date
    Feb 2004
    Location
    Utah
    Posts
    762

    Default

    what kind of enclosure is it in? With a ported/vented enclosure, you have to be careful to not let the sub play below the tuning frequency, or it can quickly overexcurt - ruining the sub. In a sealed box, a SSF isn't necessary. The natural rolloff of the sub will keep it from dying on you.
    http://www.silverdragon.com/punkie/c...net.idiot.html - Read it, know it

    Alpine 9815
    Polk MM6's in custom fiberglass door pods
    Ascendant Audio Atlas 12
    HiFonics Zeus ZX6400 - 85x2 + 350x1
    2 Gallons SecondSkin Spectrum V.2

  3. #3

    Member Sales Rating: (0)

    Join Date
    Nov 2003
    Location
    Dayton, OH
    Posts
    3,459

    Default

    if the sub is playing from 20-50, that's not a subsonic... subsonic cuts stuff below 20 (subsonic is a stupid name, it's a frickin highpass set at 15-20 Hz)... but austin's right, if you're in a sealed box, no biggie... in a ported box you'll need that 'subsonic' filter or you'll wreck the thing, eventually... so it sounds like you're talking about a lowpass set at 50 Hz, which is fine but a little low... 80 Hz is the standard cutoff, because the lower the sub is set to start, the lower your mains have to play...

    and what kinda car has fibre optics?? sounds neato...
    It's not good, very fundamentally simply not good. - geolemon

    "Its not good enough until we have real-time fearmongering. I want my fear mongered as it happens." - Shizelbs

  4. #4

    Member Sales Rating: (0)

    Join Date
    Nov 2004
    Posts
    5

    Default

    its an 04 Saab 9-3.

    anyhow, i meant the filter thats 20hz-50hz...

    its the polk momo that comes in the momo enclosure with a grill.

  5. #5

    Member Sales Rating: (0)

    Join Date
    Dec 2003
    Location
    Chattanooga, TN
    Posts
    11,827

    Default

    A subsonic filter that cuts out at 50 Hz? Usually SSF's cut out at 15 Hz. Cant be a crossover cause who would low pass their sub at 20 Hz?

    Either way, it doesnt sound right. Leave it off.

    A subsonic filter isnt there to really spare the sub but rather to keep the amp from having to reproduce frequencies you cant hear anyway so why waste the power on them.
    polkaudio sound quality competitor since 2005
    MECA SQ Rookie of the Year 06 ~ MECA State Champ 06,07,08,11 ~ MECA World Finals 2nd place 06,07,08,09
    08 Car Audio Nationals 1st ~ 07 N Georgia Nationals 1st ~ 06 Carl Casper Nationals 1st ~ USACi 05 Southeast AutumnFest 1st

    polkaudio SR6500 --- polkaudio MM1040 x2 -- Pioneer P99 -- Rockford Fosgate P1000X5D

  6. #6

    Member Sales Rating: (0)

    Join Date
    Nov 2003
    Location
    Dayton, OH
    Posts
    3,459

    Default

    whoa, where do the 04's have fibre optics? i have an 00, and i sure don't have any light beams flying around my car...

    and yeah, whatever funky filter you're talking about, it's one-of-a-kind (as you've described it), so kill it.
    It's not good, very fundamentally simply not good. - geolemon

    "Its not good enough until we have real-time fearmongering. I want my fear mongered as it happens." - Shizelbs

  7. #7

    Member Sales Rating: (0)

    Join Date
    Dec 2003
    Location
    Chattanooga, TN
    Posts
    11,827

    Default

    I just caught that too.

    Fiber optics? In a car?

    Man, I really need to keep up with the times!
    polkaudio sound quality competitor since 2005
    MECA SQ Rookie of the Year 06 ~ MECA State Champ 06,07,08,11 ~ MECA World Finals 2nd place 06,07,08,09
    08 Car Audio Nationals 1st ~ 07 N Georgia Nationals 1st ~ 06 Carl Casper Nationals 1st ~ USACi 05 Southeast AutumnFest 1st

    polkaudio SR6500 --- polkaudio MM1040 x2 -- Pioneer P99 -- Rockford Fosgate P1000X5D

  8. #8

    Member Sales Rating: (0)

    Join Date
    Nov 2004
    Posts
    5

    Default

    the whole audio setup is fiber optic.

    well, the headunit and SID (stock cpu onboard) use the mostnet fiber optic (which carries audio, info, etc). The fiber optic run throughout the car, tells of any errors (even says if the tire pressure is low, if the lights go out, etc etc). It also goes to pioneer amps (one 5 channel, and another 2 or 4 i forgot). From the amp, it has copper wire running to the speakers in the doors (at 2ohms...6 1/2s retarded yes...). I tapped that copper wire (with very limited room at that)

    there is 1 headunit that takes in fiber optic. $900 clarion. thats it =/

  9. #9

    Member Sales Rating: (0)

    Join Date
    Dec 2003
    Location
    Chattanooga, TN
    Posts
    11,827

    Default

    Ya gotta love technology!
    polkaudio sound quality competitor since 2005
    MECA SQ Rookie of the Year 06 ~ MECA State Champ 06,07,08,11 ~ MECA World Finals 2nd place 06,07,08,09
    08 Car Audio Nationals 1st ~ 07 N Georgia Nationals 1st ~ 06 Carl Casper Nationals 1st ~ USACi 05 Southeast AutumnFest 1st

    polkaudio SR6500 --- polkaudio MM1040 x2 -- Pioneer P99 -- Rockford Fosgate P1000X5D

  10. #10

    Member Sales Rating: (0)

    Join Date
    Nov 2003
    Location
    Dayton, OH
    Posts
    3,459

    Default

    indeed... i didn't know saab has already implemented the tire pressure sensors (they're required OEM by like 2008 or somesuch)... is the fibre optic stuff your doing? or is it new for this year?

    oh, and just out of curiosity, you have the T8 module, right?
    It's not good, very fundamentally simply not good. - geolemon

    "Its not good enough until we have real-time fearmongering. I want my fear mongered as it happens." - Shizelbs

  11. #11

    Member Sales Rating: (0)

    Join Date
    Feb 2004
    Location
    Utah
    Posts
    762

    Default

    I wonder why Saab chose to use fiber for all the signals like that. It is orders of magnitude more difficult than copper to repair. If something happened to the cable, it would most likely be cheaper to run a whole new cable than to try to fix it.

    Second, it's not really needed for something like low tire pressure sensors. Nothing like that requires a perfect signal. Any old copper wire would work. Now for the audio, that's great because fiber is completely immune to any interference.

    The 2 ohm speakers, I'd actually prefer. I'd rather my polks be 2 than 4 ohms because then I could get the power they want to them with the same amp I already have. Mine puts out 85x4 @ 4 ohms, but 170x4 at 2 ohms; just what the MM6's want.

    -Austin
    http://www.silverdragon.com/punkie/c...net.idiot.html - Read it, know it

    Alpine 9815
    Polk MM6's in custom fiberglass door pods
    Ascendant Audio Atlas 12
    HiFonics Zeus ZX6400 - 85x2 + 350x1
    2 Gallons SecondSkin Spectrum V.2

  12. #12

    Member Sales Rating: (0)

    Join Date
    Dec 2003
    Location
    Chattanooga, TN
    Posts
    11,827

    Default

    Yeah, but then your amp would be working much harder. This is the same as bridging a 4 channel into a 2 channel which is something Im not real fond of.

    THD tends to go up to 3% at 2 ohm loads.
    polkaudio sound quality competitor since 2005
    MECA SQ Rookie of the Year 06 ~ MECA State Champ 06,07,08,11 ~ MECA World Finals 2nd place 06,07,08,09
    08 Car Audio Nationals 1st ~ 07 N Georgia Nationals 1st ~ 06 Carl Casper Nationals 1st ~ USACi 05 Southeast AutumnFest 1st

    polkaudio SR6500 --- polkaudio MM1040 x2 -- Pioneer P99 -- Rockford Fosgate P1000X5D

  13. #13

    Member Sales Rating: (6)

    Join Date
    Dec 2003
    Location
    NC/AR
    Posts
    11,295

    Default

    And I'm sure that if the speakers were rated at 2 ohms....they'd need a lot more power...lol.......just a viscious circle...
    Quote Originally Posted by George Grand View Post
    Quote Originally Posted by Jstas View Post
    Simple question. If you had a cool million bucks, what would you do with it?
    Wonder WTF happened to the rest of my money.
    My Saga
    Equipment Pictures

    [2CH]
    Rotel RCD-02
    Yamaha KX-W900U
    Sony ST-S500ES
    Denon DP-7F
    Parasound P/HP-850
    Parasound HCA-1000A
    Klipsch RF-35


    [In Storage]
    Yamaha CDR-HD1300
    ASL Wave 20 monoblocks
    Pro-Ject Phono Box MKII


    [Car System]
    Pioneer Premier DEH-P860MP
    Memphis 16-MCA3004
    Boston Acoustic RC520

  14. #14

    Member Sales Rating: (0)

    Join Date
    Dec 2003
    Location
    Chattanooga, TN
    Posts
    11,827

    Default

    Not really. ID has some components that are 2 ohms but take the same power as their 4 ohm counterparts.
    polkaudio sound quality competitor since 2005
    MECA SQ Rookie of the Year 06 ~ MECA State Champ 06,07,08,11 ~ MECA World Finals 2nd place 06,07,08,09
    08 Car Audio Nationals 1st ~ 07 N Georgia Nationals 1st ~ 06 Carl Casper Nationals 1st ~ USACi 05 Southeast AutumnFest 1st

    polkaudio SR6500 --- polkaudio MM1040 x2 -- Pioneer P99 -- Rockford Fosgate P1000X5D

  15. #15

    Member Sales Rating: (6)

    Join Date
    Dec 2003
    Location
    NC/AR
    Posts
    11,295

    Default

    Oh; that's cool. Are their components pretty good? As good as their subs?
    Quote Originally Posted by George Grand View Post
    Quote Originally Posted by Jstas View Post
    Simple question. If you had a cool million bucks, what would you do with it?
    Wonder WTF happened to the rest of my money.
    My Saga
    Equipment Pictures

    [2CH]
    Rotel RCD-02
    Yamaha KX-W900U
    Sony ST-S500ES
    Denon DP-7F
    Parasound P/HP-850
    Parasound HCA-1000A
    Klipsch RF-35


    [In Storage]
    Yamaha CDR-HD1300
    ASL Wave 20 monoblocks
    Pro-Ject Phono Box MKII


    [Car System]
    Pioneer Premier DEH-P860MP
    Memphis 16-MCA3004
    Boston Acoustic RC520

  16. #16

    Member Sales Rating: (0)

    Join Date
    Dec 2003
    Location
    Chattanooga, TN
    Posts
    11,827

    Default

    They are pretty highly regarded.

    Ive only heard a set once a few years ago on a soundboard but they were pretty good.
    polkaudio sound quality competitor since 2005
    MECA SQ Rookie of the Year 06 ~ MECA State Champ 06,07,08,11 ~ MECA World Finals 2nd place 06,07,08,09
    08 Car Audio Nationals 1st ~ 07 N Georgia Nationals 1st ~ 06 Carl Casper Nationals 1st ~ USACi 05 Southeast AutumnFest 1st

    polkaudio SR6500 --- polkaudio MM1040 x2 -- Pioneer P99 -- Rockford Fosgate P1000X5D

  17. #17

    Member Sales Rating: (0)

    Join Date
    Nov 2003
    Location
    Dayton, OH
    Posts
    3,459

    Default

    their HLCD tweeters and powersupplies/eqs seem to be pretty well-regarded, too...
    It's not good, very fundamentally simply not good. - geolemon

    "Its not good enough until we have real-time fearmongering. I want my fear mongered as it happens." - Shizelbs

  18. #18

    Member Sales Rating: (1)

    Join Date
    Mar 2004
    Location
    College Station, TX
    Posts
    7,175

    Default

    ID anything=:D
    -Cody
    Music is like candy, you have to get rid of the rappers to enjoy it

  19. #19

    Member Sales Rating: (0)

    Join Date
    Feb 2004
    Location
    Utah
    Posts
    762

    Default

    Originally posted by MacLeod
    THD tends to go up to 3% at 2 ohm loads.
    Nah...even at two ohms, it's still less than like 1/10%. When THD for an amp at 4 ohms is measured in the hundredths, the THD doubles at 2 ohms. That sounds like a lot, but it's still in the hundredths. Not an audible difference by any means.
    http://www.silverdragon.com/punkie/c...net.idiot.html - Read it, know it

    Alpine 9815
    Polk MM6's in custom fiberglass door pods
    Ascendant Audio Atlas 12
    HiFonics Zeus ZX6400 - 85x2 + 350x1
    2 Gallons SecondSkin Spectrum V.2

  20. #20

    Member Sales Rating: (0)

    Join Date
    Nov 2003
    Location
    Dayton, OH
    Posts
    3,459

    Default

    assuming the amp is capable of putting out full power at half its rated load... lots of amps will make say 1.5 times their 4-ohm power at 2 ohms, and pushing it even that high is pretty rough on the amp - that thing is running flat-out, and that's assuming the user isn't trying to get 2x the power... at lower wattages, though, yeah, it just doubles the THD ( and halves the damping factor)
    It's not good, very fundamentally simply not good. - geolemon

    "Its not good enough until we have real-time fearmongering. I want my fear mongered as it happens." - Shizelbs

  21. #21

    Member Sales Rating: (6)

    Join Date
    Dec 2003
    Location
    NC/AR
    Posts
    11,295

    Default

    Originally posted by neomagus00
    and halves the damping factor
    Ahhh......hadn't even thought about that....
    Quote Originally Posted by George Grand View Post
    Quote Originally Posted by Jstas View Post
    Simple question. If you had a cool million bucks, what would you do with it?
    Wonder WTF happened to the rest of my money.
    My Saga
    Equipment Pictures

    [2CH]
    Rotel RCD-02
    Yamaha KX-W900U
    Sony ST-S500ES
    Denon DP-7F
    Parasound P/HP-850
    Parasound HCA-1000A
    Klipsch RF-35


    [In Storage]
    Yamaha CDR-HD1300
    ASL Wave 20 monoblocks
    Pro-Ject Phono Box MKII


    [Car System]
    Pioneer Premier DEH-P860MP
    Memphis 16-MCA3004
    Boston Acoustic RC520

  22. #22

    Member Sales Rating: (0)

    Join Date
    Dec 2003
    Location
    Chattanooga, TN
    Posts
    11,827

    Default

    Originally posted by AustinKP
    Nah...even at two ohms, it's still less than like 1/10%. When THD for an amp at 4 ohms is measured in the hundredths, the THD doubles at 2 ohms. That sounds like a lot, but it's still in the hundredths. Not an audible difference by any means.
    Yeah, that would be another of my infamous type-o's. That should have been 0.3%.
    polkaudio sound quality competitor since 2005
    MECA SQ Rookie of the Year 06 ~ MECA State Champ 06,07,08,11 ~ MECA World Finals 2nd place 06,07,08,09
    08 Car Audio Nationals 1st ~ 07 N Georgia Nationals 1st ~ 06 Carl Casper Nationals 1st ~ USACi 05 Southeast AutumnFest 1st

    polkaudio SR6500 --- polkaudio MM1040 x2 -- Pioneer P99 -- Rockford Fosgate P1000X5D

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

     

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts