Bi Amping

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  • Schurkey
    Schurkey Posts: 2,100
    edited December 2018
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    F1nut wrote: »
    The more channels you use in an AVR the less wpc it will be able to provide. Why is that? It's because of the single power supply.
    Mistake in logic.

    It's not having a single power supply that creates the issue. It's having an under-designed reduced-cost power supply. You could have separate power supplies for each channel, or even individual monoblock amplifiers, but if all the power supplies are under-sized, or if there's not enough heat sink, or if there's not enough output devices, you've got the same crippled power delivery to the speaker(s). Bi-wire four 3-watt SET amps to your pair of SDAs and see how satisfying it is.

    IF (big IF) the "single power supply" was huge enough, (and there was appropriate heat-sink, and enough output devices) there'd be no problem. In the real world, nobody makes an AVR with a large-enough power supply, heat sink, and output devices, because the whole point of an AVR is cost-reduction coupled to mass-market profit margins.
    Post edited by Schurkey on
  • tonyb
    tonyb Posts: 32,906
    edited December 2018
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    It's not a mistake in logic, he's specifically talking about AVR's. Aside from the totl AVR's in the 2k+ arena, most other mass marketed AVR's come with roughly 2 choices in a power supply. The lower end units usually have a 400-450 watt power supply, higher up the ladder will net you 750-800 watts. This to drive anywhere from 5-9 speakers. Current delivery in those power supplies is dismal to say the least.

    Preouts is the no. 1 thing I'd look for in an AVR. Without the option of adding more power, it would be worthless to me.

    I should add....because of those weak power supplies in mass marketed receivers, speaker makers must put out products compatible with them. 8 OHM, easier to drive speakers. Look at Polks lineup, most are pretty darn easy to drive off a receiver.
    Post edited by tonyb on
    HT SYSTEM-
    Sony 850c 4k
    Pioneer elite vhx 21
    Sony 4k BRP
    SVS SB-2000
    Polk Sig. 20's
    Polk FX500 surrounds

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

    Kitchen

    Sonos zp90
    Grant Fidelity tube dac
    B&k 1420
    lsi 9's
  • F1nut
    F1nut Posts: 49,801
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    Schurkey wrote: »
    F1nut wrote: »
    The more channels you use in an AVR the less wpc it will be able to provide. Why is that? It's because of the single power supply.
    Mistake in logic.

    It's not having a single power supply that creates the issue. It's having an under-designed reduced-cost power supply. You could have separate power supplies for each channel, or even individual monoblock amplifiers, but if all the power supplies are under-sized, or if there's not enough heat sink, or if there's not enough output devices, you've got the same crippled power delivery to the speaker(s). Bi-wire four 3-watt SET amps to your pair of SDAs and see how satisfying it is.

    IF (big IF) the "single power supply" was huge enough, (and there was appropriate heat-sink, and enough output devices) there'd be no problem. In the real world, nobody makes an AVR with a large-enough power supply, heat sink, and output devices, because the whole point of an AVR is cost-reduction coupled to mass-market profit margins.

    There is NO mistake in my logic.
    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

  • gp4jesus
    gp4jesus Posts: 1,969
    edited December 2018
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    So many members. So many opinions.
    rpf65 wrote: »
    Many people believe, on this site at least, your money will be better spent by getting some quality speaker cables and jumpers.
    And some of us would say first “Amp upgrade.” Your AVR ain’t cuttin’ it.

    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • pitdogg2
    pitdogg2 Posts: 24,577
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    Back when Home Theater and Stereo Review would test and display the specs on AVR's. Many so called 125wpc x 5 or 7 channels were dismal to say the least with all channels driven. A vast amount of them were at about 50wpc when all channels were in play. I chose my Denon 3805 125x 7 at the time because it was tested and still had 95 wpc with all channels driven which told me for an AVR it had a pretty good power supply.
  • rpf65
    rpf65 Posts: 2,127
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    gp4jesus wrote: »
    So many members. So many opinions.
    rpf65 wrote: »
    Many people believe, on this site at least, your money will be better spent by getting some quality speaker cables and jumpers.
    And some of us would say first “Amp upgrade.” Your AVR ain’t cuttin’ it.

    My comment was directed to the OP’s question. Bi-amping, bi-wiring, or running two independent sets of wires, from two different outputs from his AVR to the two sets of binding posts to his speakers, whichever terminology you choose. I think his money would be better spent on one set of wire, running from one set of speaker outputs from his AVR to one set of binding posts to his speakers and adding quality jumpers.

    To the only question the OP has asked, I stand by my answer.

    He may have already chosen an upgrade for his processor and amplification, and has read that bi-wiring speakers from an AVR will magically transform his system sonic nirvana. It won’t.

    Some people say they hear an improvement wiring their speakers in a bi-wire configuration, and I’ll not say that they are incorrect with their personal assessment. Most people hear no difference in running a single wire than bi-wires.

    Many people have heard an improvement by changing the metal jumper plate, that usually comes with their speakers, to good wire. This is a better choice than buying another set of wires.
  • joecoulson
    joecoulson Posts: 4,943
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    Real world example:
    I started my recent upgrade journey (I’ve had a few in my life unfortunately) with a very capable Marantz AVR and some newly acquired Polk Lsim705’s. I was told my @F1nut that my best option was to bi-amp them with the AVR because that was going to net the most power.
    While they sounded good, I could tell that at higher levels they seemed to lack some dynamics during transient signals.
    I then purchased a set of Linn LK240 monoblocks that push 125wpc into 8 ohms. This was not much more power per channel than my AVR was rated but WOW what a difference.
    After some time, my dealer offered me two more of these very capable amps for a great deal.
    I then proceeded to hook two of them to each tower. One to the high pass and one to the low.
    This change did NOT double my power. This change did however give me much more headroom and dynamics and a clear reduction in intermodulation distortion. Well worth it for me.

    Feel the heat of your AVR if you bi-amp. Always hot because they (like someone on this forum said) the are jack of all trades and master of none.
    Look up the internals of your AVR and see how much s..t is crammed in there.
    Now look at these, four of them for two speakers.
    tg961p7oi4i1.jpeg
    Obviously they don’t have to work anywhere near as hard.
    I jest about @F1nut as he is a champ and knows his stuff. @Schurkey you would be well advised to take advice with as many years in audio as him.
    These gentlemen on this forum have given me a wrath of info and guidance but more importantly, support e any decisions I made to the contrary AFTER I got to know all and made my arguments. Coming in making blanket statements here never works.

    duvc1heal04f.jpeg
    v23mf2e0ga1f.jpeg
  • gp4jesus
    gp4jesus Posts: 1,969
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    To Joecoson: I did nearly the same thing in a different way. My RTi A7 amps both have separate transformer secondary windings, bridge rectifiers, & cap banks for each channel.
    Parasound HCA-1000 One channel connected a tweeter. The other to the mid.
    Rotel 980BX. Each channel connected to one of the woofers.

    I suppose one could argue my ‘A7s are bi-amped. Another, they’re quad amped. I say tri amped.

    Same holds true for my CSi A6 amp. Could be bi amped or tri amped.

    You decide.
    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • joecoulson
    joecoulson Posts: 4,943
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    If you like it great, I always worried about different sonic signatures by using different amplifiers for the same speaker.
    But you like the outcome?
  • mhardy6647
    mhardy6647 Posts: 33,044
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    joecoulson wrote: »
    If you like it great, I always worried about different sonic signatures by using different amplifiers for the same speaker.
    But you like the outcome?


    One person's worry might well be another's opportunity for improvement.

    As a wino once said to me*
    The largest room in the world is the room for improvement.

    ______________
    * On a transit bus somewhere a bit outside of Hamilton, Bermuda, sometime in the late 1990s.
  • F1nut
    F1nut Posts: 49,801
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    Wise drunk.
    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

  • mhardy6647
    mhardy6647 Posts: 33,044
    edited December 2018
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    F1nut wrote: »
    Wise drunk.

    Indeed -- it was an interesting moment that's fairly etched into my memory. That bon mot influenced my work for the rest of my career, in fact. No kidding.
  • gp4jesus
    gp4jesus Posts: 1,969
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    joecoulson wrote: »
    But you like the outcome?
    Yu-u-u-p! Yanking the Polk XOs GREATLY improved the SQ. Upgrading to an EXO that can “correct” driver timing kicked up SQ another click or two. Replacing the tweeters will “finish” the job.

    Sound signature is for another discussion but since you opened the door. From ~125hz* on up, all Parasound. All Rotel below that*. I know that doesn’t answer your question and I’m sorry. Look me up in a year - I’ll be retired.

    Tony

    Samsung 60" UN60ES6100 LED Outlaw Audio 976 Pre/Pro Samsung BDP, Amazon Firestick, Phillips CD Changer Canare 14 ga - LCR tweeters inside*; Ctr Ch outside BJC 10 ga - LCR mids, inside* & out 8 ga Powerline: LR woofers, inside* & out *soldered LR: Tri-amped RTi A7 w/Rotels. Woofers - 980BX; Tweets & “Plugged*” Mids - 981, connected w/MP Premiere ICs Ctr Ch: Rotel RB981 -> Bi-amped CSi A6 Surrounds: Premiere ICs ->Rotel 981 -> AR 12 ga -> RTi A3. 5 Subs: Sunfire True SW Signature -> LFE & Ctr Ch; 4 Audio Pro Evidence @ the “Corners”. Power Conditioning & Distribution: 4 dedicated 20A feeds; APC H15; 5 Furman Miniport 20s *Xschop's handy work
  • mdaudioguy
    mdaudioguy Posts: 5,165
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    mhardy6647 wrote: »
    F1nut wrote: »
    Wise drunk.

    Indeed -- it was an interesting moment that's fairly etched into my memory. That bon mot influenced my work for the rest of my career, in fact. No kidding.

    Sounds like a great opening scene for your biopic. :p
  • mhardy6647
    mhardy6647 Posts: 33,044
    edited December 2018
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    Oh, I've got better -- like the time I was teaching a second year grad student to
    radioiodinate a protein sample, and she managed to dose both of us with radioactive iodine 125. :)

    Had to sit for 10 minutes at a stretch with my neck up against a Geiger counter for the next month or so to make sure I was back to baseline (as, of course, did she). :|

    That little incident was, I think, actually a transformative incident in the aforementioned other student's life, too. She changed her tack a little bit (ok, a lot), went on to do some outstanding work as a grad student and then as a postdoc, and is now tenured faculty at a very prestigious institution and something of a rock star in her field (TED talks and mainstream media articles and all). And she is still a very, very nice person with a tremendous sense of humor.


  • Hermitism
    Hermitism Posts: 4,205
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    mhardy6647 wrote: »
    Oh, I've got better -- like the time I was teaching a second year grad student to
    radioiodinate a protein sample, and she managed to dose both of us with radioactive iodine 125. :)
    Wasn't that how Bruce Banner created the Hulk? That beefy picture you posted of yourself with the long mane, that wasn't a wig, was it???
  • speedtoys
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    Welllll

    Dove right in.

    Got the VR3 new Xovers, and have redone it all...sealed, new tweeters...wow...WOW. Doing the breakin for a few weeks leaving appleTV scroll thru the library while were not at home.

    Looking at a Sunfire Signature Cinema Grande 400 now. :)

    I may use my SDA-2Bs as side channels now. They have new tweeters, and could _probably_ use new crossovers as well...but otherwise sound dang good for 1991 aged hardware still.