Is 7.1 from a 6.1 receiver possible/safe?

Discussion in 'AV Receivers' started by Miles, May 26, 2004.

  1. Miles

    Miles Second Unit

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    I feel like newbie here... I guess I am in the end...

    I have a Marantz 6300 which only has amplification for a single rear channel. I have a single Paradigm Titan hooked up right now. I'm not happy with the soundfield I'm getting and thinking I need two speakers to ensure my brain perceives the sound as coming from behind me. Somewhere I read if the single channel is directly behind your head, your brain/ears may not be able to tell if the sound is coming from behind you or in front of you...

    Which leads me to the question, could I hook up two Titans to the same amplified channel? If it works (and is relatively safe), I'm guessing it would provide me with a better sound field... Or, would I have to split the mono signal and run it through a two-channel amp to power both Titans?

    Thanks for any help,
     
  2. Aaron Gilbert

    Aaron Gilbert Second Unit

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    It will be completely safe if you wire the speakers in series. If you wire the speakers in parallel, it may or may not be safe, depending on the impedance of your speakers, the current output capability of the receiver, and how loud you like it. To wire in series, do this:

    Take the (+) wire from your receivers surround back (center) output, connect to the (+) terminal on the first speaker. Take the (-) wire from the receiver and connect it to the (-) terminal on the second speaker. Now run a wire between the two remaining speaker terminals (connect (-) on the first speaker to (+) on the second speaker). All clear?

    The only downside to the series connection is that you will have less power available than you would with a parallel connection. If the speakers are nominally eight ohms and your Marantz is rated for four ohm operation, parallel should also work, and would be preferred. For parallel, just connect all the (+) terminals and all the (-) terminals together at both speakers and the receiver.


    Aaron Gilbert
     
  3. John Garcia

    John Garcia Executive Producer

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    Running them off a separate amp is the "correct" way to do it. All Marantz receivers are rated for 6 Ohms loads minimum, but what matters is the rest of the speakers. If you have towers and a big center, you may draw too much current and clip with two Titans running off a single channel. My 3 fronts are all 4 Ohm, and I ran them off my 8300 without issue, though it sounds better with the two mains running off monoblocks now.

    When I had my Titans and my 6200, I compared a single Titan to a CC170, and stuck with the 170 because it sounded better back there.

    Where your rear center is located relative to your listening position, as well as it's calibration is going to be a big factor in how it sounds as well.
     
  4. Aaron Gilbert

    Aaron Gilbert Second Unit

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    What's "incorrect" about wiring two speakers in series? This will pose less danger to the receiver than using a single speaker.


    Aaron Gilbert
     
  5. John Garcia

    John Garcia Executive Producer

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    Not incorrect, simply that the best way would be to run the speakers off an external amp. Series wiring, if not using an external amp, would be the safest bet.
     
  6. Phil Iturralde

    Phil Iturralde Screenwriter

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    I have my two JBL S26's Rear Center Speakers (wired in-series) approx. 10-ft. behind my sweet spot and 5-ft. apart in my 20' x 30' HT/family room.

    It's been that way since April 2003 and I've had no problems playing my blockbuster DD/DTS-6.1 @ -10dB below REF Level(approx. 106dB) up to REF Level (approx. 115 dB**)!!!

    NOTE: Parallel vs. Series:
    [​IMG]

    The disadvantage of hooking up speakers in series other than getting less power out of an amplifier*, is that if one of the speakers burns up, the other one(s) stop working.

    *The AV Receiver should allow you to set the distances, then you can REF Calibrated all your HT Speakers / Sub.

    **Fast LFE SPL Peaks (RS Meter Dial = 100 to 110 respectively / Weight = C /Speed = FAST)

    ====

    FYI: REFERENCED Calibrated using Dolby Digital - "Explore Our World" DVD DD-EX Test Tones:
    .... a) Dolby Digital EX HT Speaker Test Tones = 75 dB
    .... b) Dolby Digital EX LFE Test Tone = 77 dB AVG (highest needle swing = 78 dB / lowest = 76 dB)

    Yamaha RX-V1300:
    Volume Control Display = -19.5 REF Level
    Tone Controls = Bypassed

    LEVEL MENU
    - CENTER:... -7.0
    - R SUR:....... +2.0
    - REAR CT:.. +4.5 / (pair wired in-series)
    - L SUR:........ +2.5
    - SWFR:....... -8.5*

    SETUP MENU
    - BALANCE:... L & R = 0
    - LFE:............. -11*
    - SP Delay: (in feet**)
    .......... Main LR: 9.0 ft. / (actual LT = 9' - 0" / RT = 9' - 1")
    .......... CENTER: 9.0 ft. / (was 8.5 ft.) / (actual = 8' - 9")
    .......... Rear LR: 10.0 ft. / (actual L SUR = 9' - 10 1/2" / R SUR = 10' - 2")
    .......... Rear CT: 10.0 ft. / (actual 10' - 2")

    *The Bass support is 100% A-OK when switching between my DD/DTS DVDs Digital LFE bass to my analog bass 2-channel Music CD's (DPL TV shows, VHS tapes, etc.)!!!

    ** All mesurements from my tripod mounted Radio Shack SPL Meter located @ my 'sweet spot' to each speakers.

    Read my Yamaha RX-V1300 subjective review including my Forced-ON Matrix-6.1 observation(s)! Since then, I Always Force-ON my Matrix-6.1 MODE for every DD/DTS-5.1 Blockbuster DVD's!!! "Master & Commander", "Secondhand Lions" & "Paycheck" sounded most glorious!!!

    Phil
     
  7. Aaron Gilbert

    Aaron Gilbert Second Unit

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    Phil,

    I just have to say, that's one of the most detailed and informative replies I've seen yet! Great diagrams!

    Ever since I got a 6.1 capable receiver, I also have found that forcing 6.1 (THX surround EX in my case) on all discs works spectacularly. In fact, I just watched Master and Commander tonight in DTS and was amazed. This one I saw in the theater, and I don't know if it was the sound system in the theater or just our sitting location, but it annoyed me because the surrounds were far too loud, as in they were more noticeable than the fronts for 75% of the movie. Yuck. Now I'll grant that this movie does have loud surround action, but at home it wasn't ALL the time, only when it should be, in the battle scenes, and even then the fronts and surrounds were well balanced.

    Oh and my receiver actually doesn't have power for the surround back, but does have 7.1 preouts, so I am running a stereo amplifier to power the surround back speakers. Do you think 200 watts per speaker is enough? [​IMG] Actually it has power meters, and I have yet to see it go above 40 watts, which would equate to 109dB. But I also do not listen at reference levels. Actually I picked that amp up here in the hardware for sale section, only $100, go HTF!


    Aaron Gilbert
     
  8. ChrisWiggles

    ChrisWiggles Producer

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    I have a marantz 5300, and I have done a full 7.1 setup with paradigms, the backs wired in parallel. I would do it this way.
     
  9. Phil Iturralde

    Phil Iturralde Screenwriter

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    Thanks Aaron Gilbert!!! :b


    So Chris, does your Marantz cabinet top get a little warm when you watch your DVD @ -10 dB below REF Level???

    The Sound & Vision Sept. 1999 benchmarked the following Paradigm impedance ...

    Model/Impedance (min/nominal)
    Legend ......6/10
    CC-170 ...... 5.4/10
    ADP-170 .... 3.7/6

    So, if you're using this set, wiring them in parallel, ... your amp load will see ...

    Model/Impedance (min/nominal)
    Legend ......3/5
    CC-170 ...... 1.7/5
    ADP-170 .... 1.85/3

    One day, you'll overload your Rear channel amp!

    ===

    FYI: The latest March 2004 S&V issue benchmarked the Paradigm Reference Studio 40 v.3 home theater speaker system

    (Studio 40 v.3 Fronts / CC-570 v.3 Center / ADP-470 v.3 Surrounds)
    Impedance (minimum/nominal)
    front left/right........ 3.5/5 ohms

    I certainly would not run another set of Studio 40 v.3 or ADP-470 v.3 in parallel (1.75/2.5 ohms) if I installed them @ my rear center location using one speaker output for the rear center channel amp!!!

    Just food for thought,
    Phil
     
  10. Miles

    Miles Second Unit

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    Thanks for all the replies... lots of food for thought... I did try a quick test of hooking the speakers up in a series. It seemed to work better than the single speaker for creating the effect of a sound coming from behind me. The kids were asleep so I couldn't turn it up too loud. I figured the Gladitor scene with the swinging mace would be a good demo. I think the Toy Story 2 scene with the falling lamp pole would be another one for me to try later.

    Here's the receiver/speakers I'm using:

    Speakers - 2 x Paradigm Minis, 1 X CC-350, 3 X Titan, LFE - PW2200
    Receiver - Marantz 6300
     
  11. John Garcia

    John Garcia Executive Producer

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    Technically, you're not supposed to list your gear in your signature on this forum...
     
  12. David Judah

    David Judah Screenwriter

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    When I got a cheapie little Panasonic receiver with digital amps(great sound from such an inexpensive little unit, btw), it was only 6.1, but I had 7 speakers, so I wired the back surrounds in parallel, and even listening very loud I haven't noticed it straining the amp more than it did in a 5.1 configuration.

    I guess it will be equipmemt dependent, and I was worried it might cause a problem, but so far it hasn't. I don't know if it's because of the digital amps or not. Supposedly, they are more prone to "soft" clip like tube amps, but I haven't noticed it clipping at all.

    I'd give it a try in parallel and listen carefully for problems.

    DJ
     
  13. ChrisWiggles

    ChrisWiggles Producer

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    Phil, yes that was a concern for me, the setup for a whole day of movies was mini-monitors and a CC170(i think, coulda been a 270), and mini-monitors for surrounds, and a pair of atoms in parallel for rear backs. We listened at -10 or maybe a tad less, and I had my marantz on a table for the whole day and most of the night (everything was set small, the SVS did the heavy lifting) and the heat was less than it was when I listen in s-direct with two channel.

    I currently use difficult to drive dynaudios full-range off it, and I am thinking off adding an amp for those, because if i add another dynaudio center, plus 4 atoms around the back, that is a LOT of juice for a relatively middle range receiver. But a full complement of paradigms shouldnt be too difficult to drive, though certainly a nicer receiver may come with benefits.
     
  14. Aaron Gilbert

    Aaron Gilbert Second Unit

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    For what it's worth, I tend to take manufacturer's minimum impedance ratings with a few grains of salt. Although with the Marantz in question, I actually looked through the entire manual, and all I could find was a rating for driving six ohm speakers, not a minimum impedance. Neither did the back panel specify which speaker impedances were acceptable, as is customary, unless they left it out of the PDF manual.

    My Kenwood VR-5090 specifies a six ohm minimum speaker impedance, although it also only gives it's power ratings into six ohms, not eight. I even contacted Kenwood before purchase, because all my speakers are four ohms, and was told that using four ohm speakers could/would result in damage (the usual reply). I purchased it anyway, thinking I could us an external amplifier if need be. Come to find out, it will happily run four ohm speakers in all channels, all set to large no less, and barely even get warm. In fact, my previous receiver, a Sony STR-DA30ES, which was actually rated to drive four ohm speakers, got much hotter even with all speakers set to small.

    I would certainly tend to think that Marantz receivers are in the same league as my Kenwood.

    All the above said, in my opinion, any receiver worth a darn will have protection circuitry that will shut the unit down before damage is done to the output stages as a result of shorted wires, overheating, or overcurrent. Unfortunately this information is usually not publicized.


    Aaron Gilbert
     
  15. Miles

    Miles Second Unit

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    Hey John,

    I know things have changed with the sigs over the years here. But when the sigs are part of the information of the post I don't think there's a problem... It's not like I was including it to show off what I had...
     
  16. ChrisWiggles

    ChrisWiggles Producer

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    Miles, it's because the signature is included in the search function. so if you want to search for information about a particular product, and half a dozen people have that in their sig, every time they post about ANYTHING, that post will get caught in the search, and youll have to weed through hundreds of thousands of posts that have nothing to do with that product, because that product is included in someone's signature. You can, however, as I believe others i forget who, make a picture that has text information of your equipment. It's not that we shouldn't see what you have, it's that text in the signature gets nabbed by the searching, which is a big PITA. so you can make a jpg if you want. hope that makes sense, and I am no authority on the matter, but thats the reason as explained in the past, AFAIK.
     
  17. Miles

    Miles Second Unit

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    Hey Chris,

    That sounds fair. I've edited out my signature.
     
  18. John Garcia

    John Garcia Executive Producer

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    I believe you can e-mail the moderators/ownders of HTF and ask them for a place to list your gear and provide a link in your signature.


    My 8300 has "6 Ohm nominal" on the back right where the speaker outputs are. This is the recommendation for all Marantz gear, apparently, even the MM9000, which is THX Ultra2, carried the same note. My PM7000 and MA500's state in the manual that speakers of no less than 6 Ohm nominal should be used, though a 4 Ohm power rating is given for each as well.
     

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