Subs for music - Sealed vs. Ported

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Comments

  • K_MK_M Posts: 1,396
    Running the sub from speaker level outs has disadvantages.

    Mains are not filtered, and the result is higher distortion on deep bass at any level approaching very loud.

    The best thing we did was to filter our mains at about 80Hz, it added clarity, took the load off the small woofers and they seemed cleaner for sure at high levels.

    Most all Polk mains simply can not handle really loud deep bass at high levels, when compared to a decent true sub.

    Lsi15, Lsi9, LsiC,Rta11t,M5jr+,M4,SDA 3.1TL, SDA SRS 2.3TL, Rti6....Still listing stuff, a work in progress.
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  • WLDockWLDock Posts: 2,627
    I think in some rooms, having a preamp that has a high pass crossover, like the Parasound P6 for example, mated with DSP room correction for the subs offers the best tools to help integrate a sub/subs to a set of speakers and room.
    FAMILY ROOM
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  • F1nutF1nut Posts: 42,693
    GlennDog wrote: »
    F1nut wrote: »
    the more common method is connecting speaker cables from the amp to the speakers and another set of speaker cables from the amp to the sub. Therefore, the speakers and sub receive the exact same signal at the exact same time and the exact same sonic signature. Win-win!!!

    This is exactly what I was planning to do. My amp has 2 sets of outputs, one XLR and one RCA.
    I’m using MIT shotguns to the main speakers right now. My question is, do I need an equivalent high-quality XLR cable for the Rythmik sub?
    Or use any standard “subwoof cable”?

    FYI, Rythmik only provides XLR and RCA in/out connections (no speaker level connections)

    TIA

    G

    What you're going to do is not exactly the same as what I wrote. Are you sure your Rythmik doesn't have speaker level connecrions?

    ddpld76csg4s.jpg
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • treitz3treitz3 Posts: 13,045
    Any RCA or XLR cable will work.

    Tom
    In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence.

    The best way to enjoy digital music reproduction is to never listen to good analogue reproduction.

    ~ When the law ends, tyranny begins ~
  • mhardy6647mhardy6647 Posts: 23,000
    edited March 11
    F1nut wrote: »

    Nothing, the impedance is so high the amp has no idea the sub is there.


    Ahh, I see. Thanks!

    That said... seems like the ultra-high damping factor crowd would have issues with using high-level (power amplifier level) outputs to feed a powered subwoofer.
    The load impedance of the subwoofer is finite, and of course the cable will add some DC resistance (and probably AC impedance) to the main speaker load -- and Ohm's Law kinda is what it is for resistances (and impedances) in parallel:

    1/Rt = 1/(1/Rm + 1/Rc + 1/Rs) where "Rm" would be the "main speaker plus cable" load (impedance), and "Rc" is the cable impedance running to the subwoofer, and Rs is the subwoofer input impedance. The term there that will have the most impact on the damping factor (DF being defined as nominal loudspeaker impedance load/amplifier output impedance) after the main speakers, of course, being the cable to the subwoofer.

    I am not much of a believer in damping factor as a meaningful "specification" (if for no other reason than the true "damping factor" of any given loudspeaker/amplifier pair isn't a constant but rather varies with frequency depending on the speaker impedance) -- but some folks get their undies all bunched up if they realize their DF drops from, say, 1000 to 200 because of added cabling :)

    I've got no skin in this game (my subwoofer is line-level connected :p ); I'm just musing, you know? :)

    I like to muse... and putter...


  • mhardy6647mhardy6647 Posts: 23,000
    Hmmm; I never realized that adding a bit more bottom end could be so difficult. In my case I added a single 18'' transmission line sub in a corner. I have it set on it's lowest crossover point and using the line level input I barely have it at 1/8 volume. It blends in nicely with my 1.2tl's and is noticeable only when it's turned off. I'm guessing it must be more difficult getting things right with book shelf speakers that don't go that deep?

    The perfect is the enemy of the good.
    Corollary: Close enough is close enough.

    B)
  • GlennDogGlennDog Posts: 2,033
    F1nut wrote: »

    What you're going to do is not exactly the same as what I wrote. Are you sure your Rythmik doesn't have speaker level connecrions?
    [/quote]

    Yes Sir!

    6271a6egjc76.jpeg
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    Source PSA PWT into NSD Supremo
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  • agfrostagfrost Posts: 2,269
    F1nut wrote: »
    What you're going to do is not exactly the same as what I wrote. Are you sure your Rythmik doesn't have speaker level connecrions?

    ddpld76csg4s.jpg

    Not sure which model GlennDog has but not all Rythmik subs have speaker level inputs. My F8 does not.

    duq55r3z7vab.jpg

    Jay
    SDA 2BTL * Musical Fidelity A5cr amp * Marantz DV-9500 * Modded Adcom GDA-600 DAC * Rythmik F8
    Micro Seiki DQ-50 * A hodgepodge of cabling * Belkin PF60
    Preamp rotation: Krell KSL (SCompRacer recapped) * Manley Shrimp * PS Audio 5.0
  • treitz3treitz3 Posts: 13,045
    edited March 11
    It depends on what plate amp you ordered with your sub with Rythmik. Some have the speaker level in option and some don't. I ordered mine without, as I do not like wiring my rig up that way. I use RCA out on the MF A3cr amplifier to each sub with zero audible deficiencies whatsoever. @GlennDog, this is what you are talking about doing. Not what F1nut had mentioned doing. Two completely different animals there.

    6271a6egjc76.jpeg
    Holy **** dude! You keep your volume pegged at the top? My brick house would fall down if I did that! Holy smokes.....

    [EDIT] - Never mind, it isn't even hooked up. The settings as-is would sound like doggy droppings if they were left like that.

    Tom

    In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence.

    The best way to enjoy digital music reproduction is to never listen to good analogue reproduction.

    ~ When the law ends, tyranny begins ~
  • afterburntafterburnt Posts: 5,633
    FWIW the folks at Rhytmic told me that they recommend using line level. I don't remeber why they told me that. I swore I was gonna wait till I moved to order a pair but now I am temped to get em now so I have something to monkey around with for a while.
  • F1nutF1nut Posts: 42,693
    Tom, I tried line level and high level in my office rig. I definitely noticed improved performance using the high level, it blended better.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • F1nutF1nut Posts: 42,693
    mhardy6647 wrote: »
    F1nut wrote: »

    Nothing, the impedance is so high the amp has no idea the sub is there.


    Ahh, I see. Thanks!

    That said... seems like the ultra-high damping factor crowd would have issues with using high-level (power amplifier level) outputs to feed a powered subwoofer.
    The load impedance of the subwoofer is finite, and of course the cable will add some DC resistance (and probably AC impedance) to the main speaker load -- and Ohm's Law kinda is what it is for resistances (and impedances) in parallel:

    1/Rt = 1/(1/Rm + 1/Rc + 1/Rs) where "Rm" would be the "main speaker plus cable" load (impedance), and "Rc" is the cable impedance running to the subwoofer, and Rs is the subwoofer input impedance. The term there that will have the most impact on the damping factor (DF being defined as nominal loudspeaker impedance load/amplifier output impedance) after the main speakers, of course, being the cable to the subwoofer.

    I am not much of a believer in damping factor as a meaningful "specification" (if for no other reason than the true "damping factor" of any given loudspeaker/amplifier pair isn't a constant but rather varies with frequency depending on the speaker impedance) -- but some folks get their undies all bunched up if they realize their DF drops from, say, 1000 to 200 because of added cabling :)

    I've got no skin in this game (my subwoofer is line-level connected :p ); I'm just musing, you know? :)

    I like to muse... and putter...


    Getting all technical on us, eh? Well, I have no answer for that nor have I seen it brought up in discussion before.

    I do know I once had an amp with an ultra high damping factor of 1000 that sounded like crap. However, that was likely due to the excessive amount of negative feedback.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • EndersShadowEndersShadow Posts: 16,831
    F1nut wrote: »
    I do know I once had an amp with an ultra high damping factor of 1000 that sounded like crap. However, that was likely due to the excessive amount of negative feedback.

    Well Jesse if you weren’t such a mean person the amp wouldn’t have to put up with that :tongue:

    "....not everything that can be counted counts, and not everything that counts can be counted." William Bruce Cameron, Informal Sociology: A Casual Introduction to Sociological Thinking (1963)
  • GlennDogGlennDog Posts: 2,033
    treitz3 wrote: »
    It depends on what plate amp you ordered with your sub with Rythmik. Some have the speaker level in option and some don't. I ordered mine without, as I do not like wiring my rig up that way. I use RCA out on the MF A3cr amplifier to each sub with zero audible deficiencies whatsoever. @GlennDog, this is what you are talking about doing. Not what F1nut had mentioned doing. Two completely different animals there.

    I misspoke earlier. My amp has 2 RCA outs. One 4 ohm tap and an 8 plus an XLR.
    Does "cheapo" RCA or XLR for the sub matter? I know, I know it all matters
    Power Rogue M180 monos & Adcom GFA 5802
    PS Audio PerfectWave Power Plant 10
    Rears Salk SuperCharged Surrounds
    Source PSA PWT into NSD Supremo
    Pre/Pro Integra DHC 40.1
    LCD Samsung LN46B750
    Mains Salk HT2-TL
    Center Salk HT2C
    Pre Cary SLP-05
    Wires WW & MIT
  • treitz3treitz3 Posts: 13,045
    edited March 11
    My favorite RCA cable for the subs without going into the ultra high end class of cables is the AQ King Cobra. Brings out the authority with speed and precision better than all of my other sub $500 IC's. It is of my opinion that I need not go any higher or further than those when it comes to the F-25's. You can probably score a set of used for a decent price now. I bought mine when the gettin' was still hot. That was a long, long time ago.

    Now, if I won the lottery? Perhaps I might change my mind but I feel that there is no reason at all to move up. FWIW, YMMV.

    Jesse, I observed the same thing when it came to subs I had back in the day (mostly Polk's, Klipsch's, White Van type subs and the like). That all stopped when I started futzin' around with Direct Servo subs. I actually achieve better blending now than I ever did....and this is through RCA.

    With that said, it does take me (on average) about 3 days to get them right versus 5 minutes with the regular type subs but the end result is well worth the patience and effort (This is mostly due to the amount of knobs and controls offered that wasn't the case with the older subs aforementioned). Drums have the ability to scare the livin' "you know what" out of me now. It hits your body, you can feel it go through your core and as soon as it hits? It's gone. I have actually and literally ducked before on a drum strike.

    I never achieved that with any regular sub. Ever.

    The best part about it is zero overponderance when dialed in correctly. Just sheer precision and speed. Right up my alley!!!

    Tom
    In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence.

    The best way to enjoy digital music reproduction is to never listen to good analogue reproduction.

    ~ When the law ends, tyranny begins ~
  • mhardy6647mhardy6647 Posts: 23,000
    edited March 11
    F1nut wrote: »
    mhardy6647 wrote: »
    F1nut wrote: »

    Nothing, the impedance is so high the amp has no idea the sub is there.


    Ahh, I see. Thanks!

    That said... seems like the ultra-high damping factor crowd would have issues with using high-level (power amplifier level) outputs to feed a powered subwoofer.
    The load impedance of the subwoofer is finite, and of course the cable will add some DC resistance (and probably AC impedance) to the main speaker load -- and Ohm's Law kinda is what it is for resistances (and impedances) in parallel:

    1/Rt = 1/(1/Rm + 1/Rc + 1/Rs) where "Rm" would be the "main speaker plus cable" load (impedance), and "Rc" is the cable impedance running to the subwoofer, and Rs is the subwoofer input impedance. The term there that will have the most impact on the damping factor (DF being defined as nominal loudspeaker impedance load/amplifier output impedance) after the main speakers, of course, being the cable to the subwoofer.

    I am not much of a believer in damping factor as a meaningful "specification" (if for no other reason than the true "damping factor" of any given loudspeaker/amplifier pair isn't a constant but rather varies with frequency depending on the speaker impedance) -- but some folks get their undies all bunched up if they realize their DF drops from, say, 1000 to 200 because of added cabling :)

    I've got no skin in this game (my subwoofer is line-level connected :p ); I'm just musing, you know? :)

    I like to muse... and putter...


    Getting all technical on us, eh? Well, I have no answer for that nor have I seen it brought up in discussion before.

    I do know I once had an amp with an ultra high damping factor of 1000 that sounded like crap. However, that was likely due to the excessive amount of negative feedback.

    The two go hand in hand (high DF and tonnes of NFB). :p
    But DF specs are like horsepower to some folks, y'know?

    DF of my 2A3 amp is, maybe about 8. I.e., the output impedance is about 1 ohm, I think. Heck, I guess with the Duplexes, the nominal DF may rocket up to sixteen. No NFB i the amplifier, period.

    I do have high level inputs on the subwoofer amp I am using, so it is a testable hypothesis. I like those.
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