Recommended WPC for 5jr+ Monitor Series 2?

I am reading that they can handle up to 125 watts but my current amp that is pushing 100 wpc makes them sound sort of crappy when the bass hits. I had an older technics that was 45 wpc and they almost sounded better on that. Is there a sweet spot? I am not really sure how the WPC works anyways. Thank you.

Comments

  • F1nutF1nut Posts: 40,631
    Your lesson for the day. All watts are not created equal.
    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."


  • FestYboyFestYboy Posts: 2,985
    The 5jr+ (as with most vintage Polk) like current. Give them what they want.
  • Just give them plenty of current, and good clean power, don't worry about the peak power.
    2 Channel:
    Jbl Lx44
    Optonica Sa 5105
    Blue Jean 12 gauge cable
    Audioquest evergreen 3.5mm to rca cable
    Technics Sl BD22 TT
    Randomness:
    Klh model 26's
    Peavey Pr15's
    Gls cables for peaveys
    Numark DM1175 Preamp mixer
    Random cables
    Bic f12
    Svs soundpath subwoofer cable
    Lafayette Lr-200a amplifier
  • AuxientAuxient Posts: 15
    I may need to do some research on that, how do I know what "current" a amp is pushing to the speakers
  • F1nutF1nut Posts: 40,631
    edited September 2
    Consumer grade gear will almost never list the current (amperes) rating. Once you get to the better gear it's usually listed.

    One clue, if the wpc 4 ohm rating doubles from the wpc 8 ohm rating it's a good sign that the piece is high current.
    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."


  • pkquatpkquat Posts: 604
    What amp / receiver do you have now? BTW a speakers recommended amplification is just a rough gauge. Most quality 125W amps are WAY over kill for 5Jr's based on a common max. source input level. I have had a 250W high current amp connected to my 5jr+. I just don't have to move the volume knob on the pre-amp as much before they reach there limit compared to some larger speakers.

    Plenty of decent used amps and receivers can be found on craigslist and offer up. We can help find something within your budget and preference.
  • tonybtonyb Posts: 30,165
    Auxient wrote: »
    I may need to do some research on that, how do I know what "current" a amp is pushing to the speakers

    Current, as a spec, is usually listed as "amperes peek to peek". You won't find that spec on receivers, mostly amplifiers. Even then, some leave that tidbit of info out.

    Also take note that, an amplifier does not throw out it's rated power as soon as you flip it on, nor does a receiver for that matter either.
    HT SYSTEM-2 channel
    Sony 850c 4k
    Pioneer elite vhx 21
    Sony 4k BRP
    SVS SB-2000
    Dynaudio Audience 72
    Polk FX500 surrounds
    Cary xciter dac
    Cullen modded Sonos
    Joule la-100 pre
    B&k Ref 4420 amp

    Cables-
    Acoustic zen Satori speaker cables
    Acoustic zen Matrix 2 IC's
    Analysis plus crystal oval ic's
    Wireworld eclipse 7 ic's
    Audio metallurgy ga-o digital cable

    Kitchen

    Sonos zp90
    B&k 1430
    Tad 803 speakers
  • mhardy6647mhardy6647 Posts: 19,580
    edited September 4
    The first important parameter here is the loudspeaker sensitivity (see below). It would also be really nice to know the nominal impedance (see below, too!) and the impedance curve (which might be found in a thorough review of the kind done by Stereophile or the late, lamented Audio magazine) of the speaker. Knowing at least two of these things can help one make a very well educated guess as to what kind of amplifier would be a good match. That said, these were sold as modest loudspeakers for modest systems at a time when "modest" amplifier or receiver power outputs were on the order of 40 to 80 wpc. A good amplifier in that neighborhood should perform well with them, I would think.

    Here are some specifications I found at https://www.hifiengine.com/manual_library/polk-audio/monitor-5jr.shtml

    wfjjbyvrgdor.png

    Whether any or all of these nominal specs apply to the "Series 2" model in question, I don't know (sorry!) but we see a fairly high sensitivity specification of 91 dB (that should be measured SPL at a distance of 1 meter from the speaker with an input signal level of 2.83 AC volts). The nominal impedance of 6 ohms means that 2.83 volts corresponds to input power of 1.33 watts. 2.83 volts is 1.0 watts into 8 ohms. :)

    The "6 ohm" nominal rating is kinda in-betweeny :p I'd say erring on the side of caution with a "high current" amplifier is wise if practical (affordable) :) How do you know if an amp is "high current"? Well... you can trust the advice of others, or reviews, or your own auditions or - if all else fails :p look for power output specifications for the amplifier in question. As @F1nut noted, if the rated power output into a 4 ohm load is close to double that rated into an 8 ohm load, then it's "probably" a pretty beefy amplifier, capable of delivering fairly high levels of current.

    The same input voltage into a 4 ohm load represents twice the power of that same voltage into an 8 ohm load, but requires twice the current (in amperes) to be supplied! This is a direct and unavoidable consequence of good ol' Ohm's Law!
    A current limited amplifier won't be able to develop twice the power into a 4 ohm load as an 8 ohm load -- it'll run out of juice (so to speak).

    PS I don't think that the (ahem) "fluid-coupled subwoofer" (passive radiator) on the 5jr+ is 8" as those specs claim... so I don't know how accurate any of the other specs are, either :|

    Hope this is helpful, or at least interesting! :)
    Post edited by mhardy6647 on
  • pitdogg2pitdogg2 Posts: 11,475
    Nope it is a 6.5" passive Doc. I'm sure it's pretty accurate other than that.
  • mhardy6647mhardy6647 Posts: 19,580
    edited September 4
    pkquat wrote: »
    What amp / receiver do you have now? BTW a speakers recommended amplification is just a rough gauge. Most quality 125W amps are WAY over kill for 5Jr's based on a common max. source input level. I have had a 250W high current amp connected to my 5jr+. I just don't have to move the volume knob on the pre-amp as much before they reach there limit compared to some larger speakers...
    tonyb wrote: »
    ...
    Also take note that, an amplifier does not throw out it's rated power as soon as you flip it on, nor does a receiver for that matter either.

    So -- these comments get into some interesting territory :)

    @tonyb is right on (as they used to say back in the olden days)! An amplifier that is fed zero signal (zero volts AC) will (should!) output zero watts of power into the loudspeakers connected to it. Now, this doesn't mean that the amplifier itself isn't generating some power -- it almost certainly is, but that power is being
    wasted as heat
    and not doing the work for which it is intended. Its intended work is to make speaker drivers' cones or domes or membranes to wiggle! :)

    If this causes flashbacks to high school (or college) physics, there's good reason :)

    The power amplifier will begin to output power (in the form of an amplified version of the input signal) in proportion to the level of the input signal. The proportion is linear; the power amplifier is meant to be a linear amplifier, by
    the definition of hifi! :)

    The constant of proportionality between the input signal and the output signal is,
    essentially, a measure of the overall gain of the amplifier. Gain isn't represented quite this way (for practical reasons, units of decibels are used... but I don't want to get too deep into the details too fast, believe it or not!).

    In practice, the amplifier takes a low-ish voltage, low current signal (one of very low power) and converts it into a higher voltage and higher current signal (much higher power) to drive the load (speaker/speakers).

    Now, the amplifier has a volume control. When that control is wide open, the full gain of the amplifer can be realized, but the output power will still depend on the level of the input signal! The volume control is an attenuator -- it lowers the signal to the power amplifier as it it turned (from maximum to minimum). The rate of change of that level of attenuation as the knob is turned is called the "taper" of the volume control. For practical reasons, on an audio amplifier, the "taper" isn't linear, it is logarithmic... but the precise taper varies from model to model*.

    How high the volume control has to be turned to get a certain level of "loudness" (SPL) from a pair of speakers depends a lot of things! It depends on the output signal level of the "source" component, it depends on the taper of the volume control, the gain of the amplifier (all "active" stages thereof), and the loudspeaker sensitivity. It also depends on the size and "conditions" of the room in which the speakers are, umm, speaking. :)

    Why do I tell you all of this? How high one has to turn the volume control doesn't really tell us much about how much power is being delivered to the speakers. The speakers may tell you, though, if they start to sound distressed! It takes a lot of change of input electrical power to effect a fairly small change in the output acoustic power of a speaker! A 3 dB increase in SPL ('volume') is barely audible to most folks, but requires twice as much power. That two-fold power change may be more than the speakers can handle, if the amplifier is capable of very high output power -- which may explain @pkquat's observation of his speakers "reach[ing] [their] limit" with the bigger amplifier.

    I hope this provides some context for a bunch of really good responses to the original question, and that it makes at least a little sense! :p

    ______________________
    * Not to get too deep in the weeds, but the home theater craze did actually lead to some standardization (calibration) of attenuation levels. The SPL behavior of two systems calibrated to the same standard can be comparable in a predictable way. I think this is common in HT systems, but not so much in "audiophile" two-channel hifi audio systems.



  • AuxientAuxient Posts: 15
    pkquat wrote: »
    What amp / receiver do you have now? BTW a speakers recommended amplification is just a rough gauge. Most quality 125W amps are WAY over kill for 5Jr's based on a common max. source input level. I have had a 250W high current amp connected to my 5jr+. I just don't have to move the volume knob on the pre-amp as much before they reach there limit compared to some larger speakers.

    Plenty of decent used amps and receivers can be found on craigslist and offer up. We can help find something within your budget and preference.

    I am using a Fisher RS-9005 integrated amplifier. And thank you everyone for the responses. This is all new to me.
  • pkquatpkquat Posts: 604
    I couldn't find much on what era that Fisher is, but it looks like its around the 80's. It's supposed to have about 90WPC, which should be more than enough. Fishers from around that time were known to have issues, and not known for their longevity. I have a cheaper low current AVR receiver that has about the same output and is more than enough for the 5Jr's. I suspect something is not quite right with the receiver any more, or some other part of the electronics. If you can bypass the EQ on the receiver, do it, otherwise make all of the sliders are in the middle at zero. While I am not familiar with that particular model, I think many other receivers and amps will give you a much better sound.

    The 5Jr's are about 4 Ohm nominal load as I recall. The driver is a MW6502. The tweeters will add some resistance.

    I guess the next question, is what is your budget for amplifier upgrades. Welcome to the rabbit hole. :pensive:

    PS you can find many things better for ~$100.
  • FestYboyFestYboy Posts: 2,985
    Get a NAD 7240PE and call it a day
  • audioluvraudioluvr Posts: 497
    mhardy6647 wrote: »
    pkquat wrote: »
    What amp / receiver do you have now? BTW a speakers recommended amplification is just a rough gauge. Most quality 125W amps are WAY over kill for 5Jr's based on a common max. source input level. I have had a 250W high current amp connected to my 5jr+. I just don't have to move the volume knob on the pre-amp as much before they reach there limit compared to some larger speakers...
    tonyb wrote: »
    ...
    Also take note that, an amplifier does not throw out it's rated power as soon as you flip it on, nor does a receiver for that matter either.

    So -- these comments get into some interesting territory :)

    @tonyb is right on (as they used to say back in the olden days)! An amplifier that is fed zero signal (zero volts AC) will (should!) output zero watts of power into the loudspeakers connected to it. Now, this doesn't mean that the amplifier itself isn't generating some power -- it almost certainly is, but that power is being
    wasted as heat
    and not doing the work for which it is intended. Its intended work is to make speaker drivers' cones or domes or membranes to wiggle! :)

    If this causes flashbacks to high school (or college) physics, there's good reason :)

    The power amplifier will begin to output power (in the form of an amplified version of the input signal) in proportion to the level of the input signal. The proportion is linear; the power amplifier is meant to be a linear amplifier, by
    the definition of hifi! :)

    The constant of proportionality between the input signal and the output signal is,
    essentially, a measure of the overall gain of the amplifier. Gain isn't represented quite this way (for practical reasons, units of decibels are used... but I don't want to get too deep into the details too fast, believe it or not!).

    In practice, the amplifier takes a low-ish voltage, low current signal (one of very low power) and converts it into a higher voltage and higher current signal (much higher power) to drive the load (speaker/speakers).

    Now, the amplifier has a volume control. When that control is wide open, the full gain of the amplifer can be realized, but the output power will still depend on the level of the input signal! The volume control is an attenuator -- it lowers the signal to the power amplifier as it it turned (from maximum to minimum). The rate of change of that level of attenuation as the knob is turned is called the "taper" of the volume control. For practical reasons, on an audio amplifier, the "taper" isn't linear, it is logarithmic... but the precise taper varies from model to model*.

    How high the volume control has to be turned to get a certain level of "loudness" (SPL) from a pair of speakers depends a lot of things! It depends on the output signal level of the "source" component, it depends on the taper of the volume control, the gain of the amplifier (all "active" stages thereof), and the loudspeaker sensitivity. It also depends on the size and "conditions" of the room in which the speakers are, umm, speaking. :)

    Why do I tell you all of this? How high one has to turn the volume control doesn't really tell us much about how much power is being delivered to the speakers. The speakers may tell you, though, if they start to sound distressed! It takes a lot of change of input electrical power to effect a fairly small change in the output acoustic power of a speaker! A 3 dB increase in SPL ('volume') is barely audible to most folks, but requires twice as much power. That two-fold power change may be more than the speakers can handle, if the amplifier is capable of very high output power -- which may explain @pkquat's observation of his speakers "reach[ing] [their] limit" with the bigger amplifier.

    I hope this provides some context for a bunch of really good responses to the original question, and that it makes at least a little sense! :p

    ______________________
    * Not to get too deep in the weeds, but the home theater craze did actually lead to some standardization (calibration) of attenuation levels. The SPL behavior of two systems calibrated to the same standard can be comparable in a predictable way. I think this is common in HT systems, but not so much in "audiophile" two-channel hifi audio systems.



    Too many words... Brain hurts.
    F1nut wrote: »
    Your lesson for the day. All watts are not created equal.

    Listen to Jesse ( not many words either...)
    Home System:
    SDA 1C's - Full mod with the help by Dave...
    B&K Reference 50 Pre
    B&K M200 Sonata Monoblocks
    Cambridge Audio DVD 99
    Sangean HD FM Tuner

    Barn system:
    SDA SRS 2.3's Full mod done by myself
    Carver C-1 pre
    Carver M1.5t
  • AuxientAuxient Posts: 15
    pkquat wrote: »
    I couldn't find much on what era that Fisher is, but it looks like its around the 80's. It's supposed to have about 90WPC, which should be more than enough. Fishers from around that time were known to have issues, and not known for their longevity. I have a cheaper low current AVR receiver that has about the same output and is more than enough for the 5Jr's. I suspect something is not quite right with the receiver any more, or some other part of the electronics. If you can bypass the EQ on the receiver, do it, otherwise make all of the sliders are in the middle at zero. While I am not familiar with that particular model, I think many other receivers and amps will give you a much better sound.

    The 5Jr's are about 4 Ohm nominal load as I recall. The driver is a MW6502. The tweeters will add some resistance.

    I guess the next question, is what is your budget for amplifier upgrades. Welcome to the rabbit hole. :pensive:

    PS you can find many things better for ~$100.

    The problem I am having is that I live in a relatively small town so finding anything of value is next to impossible. The nearest large city with more selection is 200+ miles away. And the the shipping online for a heavy receiver is outrageous.
  • mhardy6647mhardy6647 Posts: 19,580
    edited September 7
    Auxient wrote: »
    pkquat wrote: »
    I couldn't find much on what era that Fisher is, but it looks like its around the 80's. It's supposed to have about 90WPC, which should be more than enough. Fishers from around that time were known to have issues, and not known for their longevity. I have a cheaper low current AVR receiver that has about the same output and is more than enough for the 5Jr's. I suspect something is not quite right with the receiver any more, or some other part of the electronics. If you can bypass the EQ on the receiver, do it, otherwise make all of the sliders are in the middle at zero. While I am not familiar with that particular model, I think many other receivers and amps will give you a much better sound.

    The 5Jr's are about 4 Ohm nominal load as I recall. The driver is a MW6502. The tweeters will add some resistance.

    I guess the next question, is what is your budget for amplifier upgrades. Welcome to the rabbit hole. :pensive:

    PS you can find many things better for ~$100.

    The problem I am having is that I live in a relatively small town so finding anything of value is next to impossible. The nearest large city with more selection is 200+ miles away. And the the shipping online for a heavy receiver is outrageous.

    As Louis Pasteur observed:
    Chance favors the prepared mind.

    You might be surprised what you may find in your own neighborhood. That's why, like, supercharged 1930s Bentleys turn up in barn, you know? :)

    Actually, buying new electronics can be a pretty cost-effective approach as well -- here, again, Pasteur's Dictum (as I like to call it) applies.

    thuvi1s8u1s5.png

  • F1nutF1nut Posts: 40,631
    Auxient wrote: »
    pkquat wrote: »
    I couldn't find much on what era that Fisher is, but it looks like its around the 80's. It's supposed to have about 90WPC, which should be more than enough. Fishers from around that time were known to have issues, and not known for their longevity. I have a cheaper low current AVR receiver that has about the same output and is more than enough for the 5Jr's. I suspect something is not quite right with the receiver any more, or some other part of the electronics. If you can bypass the EQ on the receiver, do it, otherwise make all of the sliders are in the middle at zero. While I am not familiar with that particular model, I think many other receivers and amps will give you a much better sound.

    The 5Jr's are about 4 Ohm nominal load as I recall. The driver is a MW6502. The tweeters will add some resistance.

    I guess the next question, is what is your budget for amplifier upgrades. Welcome to the rabbit hole. :pensive:

    PS you can find many things better for ~$100.

    The problem I am having is that I live in a relatively small town so finding anything of value is next to impossible. The nearest large city with more selection is 200+ miles away. And the the shipping online for a heavy receiver is outrageous.

    You need to be more dedicated. 200 miles ain't nothin'.
    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."


Sign In or Register to comment.

Howdy, Stranger!

It looks like you're new here. If you want to get involved, click one of these buttons!