RTI A7 Bi Amp Impedance / Resistance

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  • F1nut
    F1nut Posts: 49,806
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    Well, you certainly would be increasing the wire gauge, so give it a shot and let us know what you think.
    Political Correctness'.........defined

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  • lightman1
    lightman1 Posts: 10,776
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    gp4jesus wrote: »
    F1nut wrote: »
    The only difference when bi-wiring is you are effectively increasing the wire gauge, which could be done with a single run as well.
    Suppose I cut the length in half (10' to 5') and take the (now) spare (5') piece and re-connect as double 5' run of 10 ga. Should I hear a difference?

    But then you would be bringing your speakers in closer and possibly narrowing the soundstage. Thereby a possible change from the original soundstage could negate any diffence you may hear in the 5' parallel run.

    Anybody?
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  • gce
    gce Posts: 2,158
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    You could move your chair 5' to compensate. :|
    Anaheim Hills CA,
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  • gp4jesus
    gp4jesus Posts: 1,969
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    I did... ...about 15 years ago. Had a pair of dual 12" driver isobaric subs. Originally each connected w/ a single 10' run, one driver daisy chained (and soldered) to the other. Took several weeks, HOURS of listening, and a bunch of testing to dial them in.

    Ohhhh I forgot to mention... ...I used 10 ga wire - calculated length resistance .01 ohms for 10 feet - important I think to mention. Anyway, "Al-ri-ght, they're dialed in." Listening bliss, right? Nope. What does a single tweak-a-holic do now?

    Well I noticed I didn't really need 10' to connect them, so for fun I cut the wire in half. Then "Hey! I'll give each driver their OWN connection," (BI-WIRED!), soldering them at the driver end.

    Now I have a new problem because they're LOUDER!! And I don't mean a teeny weeny bit louder either. Some testing and (a few less hours than before) of listening later, dialed in again.

    For 15 years I've puzzled over why such a tiny change produced a big difference. What do I know: they were nominally 4 ohms w/a 3 ohm low point in their impedance curve and the "bi-wire" reduced the resistance a mere .0075 ohms.

    Recently I had an "ah-ha" moment: each driver in an isobaric alignment presents a different load along w/different back EMF "characteristics" to the amp. I theorized those "characteristics' interfered with each other. Bi-wiring separated them.

    Anyone got a better theory?
    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
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  • F1nut
    F1nut Posts: 49,806
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    Bi-wiring doesn't really separate them. Bi-amping would.
    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

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  • gp4jesus
    gp4jesus Posts: 1,969
    edited May 2016
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    F1nut wrote: »
    Bi-wiring doesn't separate them.
    You didn't read my post very carefully nor have a clue why they got louder.
    The "bi-wire' theory is just that, a theory. That's why I closed my post asking "Got a better theory?"

    I used to think it was the resistance reduction until I resigned myself that .0075 ohms less resistance couldn't result in a 3-6dB increase in volume

    So I ask again: anyone got a better explanation?
    Post edited by [Deleted User] on
    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
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  • F1nut
    F1nut Posts: 49,806
    edited May 2016
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    Resistance isn't everything.

    A 3-6dB increase in volume? That's quite a bit. Perhaps something wasn't hooked up properly the first time.

    One other thing, lose the attitude.
    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

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  • gp4jesus
    gp4jesus Posts: 1,969
    edited May 2016
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    F1nut wrote: »
    Resistance isn't everything.
    "I wish I said that." Oh... that's right, I did!

    "I used to think it was the resistance reduction until I resigned myself that .0075 ohms less resistance couldn't result in a 3-6dB increase in volume"

    F1nut wrote: »
    A 3-6dB* increase* in volume?
    ...is an estimate. 3 dB is the smallest difference we can hear. I'm certain the diff was greater.
    F1nut wrote: »
    Perhaps something wasn't hooked up properly the first time.
    Not a chance. During the "single run" stage of listening & testing I had taken apart & reassembled the TWO unsoldered connections several times.


    Post edited by [Deleted User] on
    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
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  • Nightfall
    Nightfall Posts: 10,073
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    A combative attitude isn't going to get you very far.
    afterburnt wrote: »
    They didn't speak a word of English, they were from South Carolina.

    Village Idiot of Club Polk
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  • F1nut
    F1nut Posts: 49,806
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    A combative attitude isn't going to get you very far.

    No kidding, sorry I bothered.
    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

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  • nooshinjohn
    nooshinjohn Posts: 25,103
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    F1nut wrote: »
    Resistance isn't everything.


    Resistance is futile.

    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
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  • don0
    don0 Posts: 78
    edited May 2016
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    F1nut wrote: »
    Resistance isn't everything.

    A 3-6dB increase in volume? That's quite a bit. Perhaps something wasn't hooked up properly the first time.

    One other thing, lose the attitude.

    What happened to your reading comprehension?
    Post edited by don0 on
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  • txcoastal1
    txcoastal1 Posts: 13,132
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    don0 wrote: »
    F1nut wrote: »
    Resistance isn't everything.

    A 3-6dB increase in volume? That's quite a bit. Perhaps something wasn't hooked up properly the first time.

    One other thing, lose the attitude.

    What happened to your reading comprihension?

    What happened to your spelling?
    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
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  • lightman1
    lightman1 Posts: 10,776
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    txcoastal1 wrote: »
    don0 wrote: »
    F1nut wrote: »
    Resistance isn't everything.

    A 3-6dB increase in volume? That's quite a bit. Perhaps something wasn't hooked up properly the first time.

    One other thing, lose the attitude.

    What happened to your reading comprihension?

    What happened to your spelling?

    What happened to your face?
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  • txcoastal1
    txcoastal1 Posts: 13,132
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    lightman1 wrote: »
    txcoastal1 wrote: »
    don0 wrote: »
    F1nut wrote: »
    Resistance isn't everything.

    A 3-6dB increase in volume? That's quite a bit. Perhaps something wasn't hooked up properly the first time.

    One other thing, lose the attitude.

    What happened to your reading comprihension?

    What happened to your spelling?

    What happened to your face?


    wa09mg4x9rad.jpg

    DSkip wrote: »
    lightman1 wrote: »
    txcoastal1 wrote: »
    don0 wrote: »
    F1nut wrote: »
    Resistance isn't everything.

    A 3-6dB increase in volume? That's quite a bit. Perhaps something wasn't hooked up properly the first time.

    One other thing, lose the attitude.

    What happened to your reading comprihension?

    What happened to your spelling?

    What happened to your face?

    Too much time spent with Russman.

    wait.jpg 109.2K
    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
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  • don0
    don0 Posts: 78
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    txcoastal1 wrote: »
    don0 wrote: »
    F1nut wrote: »
    Resistance isn't everything.

    A 3-6dB increase in volume? That's quite a bit. Perhaps something wasn't hooked up properly the first time.

    One other thing, lose the attitude.

    What happened to your reading comprihension?

    What happened to your spelling?

    Typo
    Was not talking to you, unless you are f1nut.
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  • lightman1
    lightman1 Posts: 10,776
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    don0 wrote: »
    txcoastal1 wrote: »
    don0 wrote: »
    F1nut wrote: »
    Resistance isn't everything.

    A 3-6dB increase in volume? That's quite a bit. Perhaps something wasn't hooked up properly the first time.

    One other thing, lose the attitude.

    What happened to your reading comprihension?

    What happened to your spelling?

    Typo
    Was not talking to you, unless you are f1nut.

    That's Billy Rayjimbob. F1 is Clyde.
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  • F1nut
    F1nut Posts: 49,806
    edited May 2016
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    Was not talking to you, unless you are f1nut.

    Would you like to buy a vowel?
    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

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  • Nightfall
    Nightfall Posts: 10,073
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    don0 wrote: »
    txcoastal1 wrote: »
    don0 wrote: »
    F1nut wrote: »
    Resistance isn't everything.

    A 3-6dB increase in volume? That's quite a bit. Perhaps something wasn't hooked up properly the first time.

    One other thing, lose the attitude.

    What happened to your reading comprihension?

    What happened to your spelling?

    Typo
    Was not talking to you, unless you are f1nut.

    Are you serious? F1Nut was talking to gp4jesus. I believe it is your reading comprehension that's in question.
    afterburnt wrote: »
    They didn't speak a word of English, they were from South Carolina.

    Village Idiot of Club Polk
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  • don0
    don0 Posts: 78
    edited May 2016
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    Nightfall wrote: »
    don0 wrote: »
    txcoastal1 wrote: »
    don0 wrote: »
    F1nut wrote: »
    Resistance isn't everything.

    A 3-6dB increase in volume? That's quite a bit. Perhaps something wasn't hooked up properly the first time.

    One other thing, lose the attitude.

    What happened to your reading comprihension?

    What happened to your spelling?

    Typo
    Was not talking to you, unless you are f1nut.

    Are you serious? F1Nut was talking to gp4jesus. I believe it is your reading comprehension that's in question.

    Did you know that I was not talking to you?

    I know who f1nut was talking to but he misunderstood what was said about resistance.
    He also knows why I made the comment about his readingcomprehension. He did the same thing that he accused me of, on one of gp4jesus's post above.

    .
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  • lightman1
    lightman1 Posts: 10,776
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    y44wbgscdkgw.gif
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  • F1nut
    F1nut Posts: 49,806
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    No dono, there's nothing wrong with my reading comprehension and if you knew anything about isobaric subs you would have known where I was going. In the meantime, stop embarrassing yourself.
    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

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  • Nightfall
    Nightfall Posts: 10,073
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    lightman1 wrote: »
    y44wbgscdkgw.gif

    Seizure?
    afterburnt wrote: »
    They didn't speak a word of English, they were from South Carolina.

    Village Idiot of Club Polk
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  • lightman1
    lightman1 Posts: 10,776
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    Trying to be a bada$$ fail.
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  • gp4jesus
    gp4jesus Posts: 1,969
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    DSkip wrote: »
    ...the hookup order on the subwoofers changed*. I suspect when you rewired them, the amp was presented with a lower ohm load, thereby drawing more power out of the amp. This should have roughly doubled the output.
    You are absolutely correct about how an impedance change affects amp output and, ultimately, volume, everything else being equal.

    A couple of side notes:
    1. I neglected to mention earlier these subs were quasi DIY - home made based upon on a tried & true commercial design - the source of the impedance curve info.
    2. I hard wired the speaker wires resulting in each having a 10' "tail" before and two 5' tails after the bi-wire.
    3. Right after I put these in service I discovered the (dedicated) amp* ran significantly warmer at lower volumes than w/any others speakers at high volumes. I kept it* on a milk crate to enhance convection cooling. That didn't change after the bi-wire.
    * using it in my home theatre today

    Unfortunately for those so willing to help, I'm certain the drivers were paralleled before the bi wire. Due to the isobaric alignment I was VERY careful soldering the drivers the first time. I would have noticed the series wiring "mistake" during the bi-wire mod. Further, I regret not following MY protocol - rewiring one, listening to each "solo," then deciding to either rewire the other or reverse the former.

    Thanks for your thoughts, 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
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  • lightman1
    lightman1 Posts: 10,776
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    You say the woofers are in an isobaric array. Are the woofers head to head, back to back or front to back? And did you wire one woofer in phase and the other out of phase in parallel?
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  • lightman1
    lightman1 Posts: 10,776
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    lt4mmweiukj2.png
    Any of these configurations?
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  • gp4jesus
    gp4jesus Posts: 1,969
    edited May 2016
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    Front to front. Ext dimensions (LWH) 14" X 14" X ~42", 3 cu ft, to the best of my recollection.
    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
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  • lightman1
    lightman1 Posts: 10,776
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    Right on. And going back to the wiring at the terminals. Is one wired in phase and the other wired in reverse phase. (Out of phase)?
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  • gp4jesus
    gp4jesus Posts: 1,969
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    Sorry lightman1.

    Unless you have a way to travel to the year 1991, month of May or June, Los Alamitos, CA, I can't say but...

    I also forgot mention those were part of a 2 channel tri-amped system using 3 different brands of amps. Part of the challange of correctly setting up same includes checking each amp for phase inversion. Failing to do so makes for very disappointing SQ.

    1991 wasn't my "first rodeo" in the world of bi & tri amped systems.

    Thanks, 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
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