Volume Difference Between 2 ch. stereo and Surround Mode?

Discussion in 'AV Receivers' started by JerryMa, Mar 29, 2005.

  1. JerryMa

    JerryMa Stunt Coordinator

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    I just hooked my new JBLs (E50 mains, EC25, E10s) to my NAD T762 and sat down to do some listening but am having some issues with the volume in 2 channel mode vs. 5.0.

    2-channel stereo sounds like it always did, but when I switch to a DVD the -20 db that is adequate for music is barely a whisper on movie soundtracks. When I raised the volume, the NAD shut off at +5 db. I tried the sound test (the tones) and noticed the center channel was lower than the rest; when I started to raise the level of the center the system shut itself off again. Finally, I unplugged it for a while thinking I did something to annoy the receiver while I was hooking up the speakers.

    Since reconnecting to the outlet, I haven't raised the volume much to see if the receiver will still shut itself off but the volume situation is the same. The NAD manual wasn't terribly helpful with this issue and I'm a relative newbie with regard to home theater so it may be something obvious that I'm missing.

    I fiddled with audio settings through the DVD player but that didn't help either. Any ideas??
     
  2. John S

    John S Producer

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    I think your 1st priority is to figure out why it is shutting off. All your speakers seem to be 8ohm. Unless a tweet or something is blown, or there is some problem with a connection / wire, there is no reason it should be shutting off.
     
  3. JerryMa

    JerryMa Stunt Coordinator

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    John S.:
    It took a while to get the wires cut and connected to the NAD; I couldn't believe how hard it was to make the connections. The rear panel on the T762 is very cumbersome.

    As a result, some of my trims are a bit sloppy and I was thinking about getting bannana plugs for the speaker terminals on the receiver. I thought about the wire connections being an issue and that's why I'm hoping the bannana plugs might be neater and create better connections.

    The JBLs are indeed all 8 ohms. And I'm figuring the NAD has more than enough power to drive the setup.

    Regarding a blown tweeter, when I did the sound test to all channels, the center sounded lower than the rest. If there's a problem with one of the speakers, could it be the center, then?
     
  4. John Garcia

    John Garcia Executive Producer

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    Is this on the same source or two different sources? Analog or digital or both?

    One thing you can try is hooking just one speaker at a time up to the receiver to see if it is a particular speaker that has a problem.
     
  5. John S

    John S Producer

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    A blown tweet in a center, sure could explain it.

    I would simply re-do the connections 1st for sure.
     
  6. JerryMa

    JerryMa Stunt Coordinator

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    "Is this on the same source or two different sources? Analog or digital or both?"

    If I understand the question correctly: CDs and the tuner play at the same volume they've always played, basically either 2-channel source is fine. DVD audio when its 5.0 is screwed up. I think I did 2-channel audio through the DVD player and it sounded OK too, need to recheck this when I get home to be sure.

    All audio connections are analog.
     
  7. John S

    John S Producer

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    Your doing 5.0 via 5 RCA Multi-channel input plugs?
    Interesting. Your center is well matched?

    I think I would try removing the center (disconnect it) then tell the pre/pro you don't have a center and see what happens. Sort of 5.0 via 4 speakers as recently posted here in another thread. If it stays on, really check the wiring to the center, if all is good. I would sure suspect the center, especially since you state it has lower output in general.
     
  8. John Garcia

    John Garcia Executive Producer

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    What CD and DVD players are you running? With the nice DACs and bass management in the 762, I'd probably run everything I could via digital to it unless the players were pretty nice.

    The reason I asked that was because it's not uncommon for there to be volume discrepancies when going from one source to another, and when using a DVD player's multi-channel analog output this is pretty common, but it still should not shut down. You may need to check the speaker levels in the player. I leave my SACD player's levels set to "0" and adjust accordingly using the receiver's level adjustment on the m/c analog input.

    Get the banana plugs too. Just makes it a lot easier and cleaner.

    Center is a EC25 he just purchased with the E50 mains.
     
  9. questrider

    questrider Second Unit
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    It is my opinion that the EC25 is not a good center speaker (2-way vs. 3-way EC35) and doesn't match the E50s and up very well. This could have a little to do with the center sounding different and/or lower than the E50s.
     
  10. JerryMa

    JerryMa Stunt Coordinator

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    John,

    The CD and DVD players are both Sony. I had checked the speaker levels on the DVD player and they are all set to "0".

    I was expecting a volume discrepancy with different sources but am surprised that its so significant. And the fact that it forced the receiver to shut down is bothersome.

    This leads me to believe that I did something wrong when connecting my speaker wire. If the center is bad, I'd be surprised that it would pull down the volume across all 5 channels when I'm listening in surround mode.

    I should be able to get the bannana plugs today or tomorrow and will install those. The cleaner connection to the receiver's speaker terminals will ease my mind, anyway, and it'll give me a chance to double check the connections.

    In case its not the connections, I can check/adjust other audio settings on the DVD player. I can control sound format output and speaker size. Maybe I'll try to disable all of those things so the receiver does all the processing?
     
  11. JerryMa

    JerryMa Stunt Coordinator

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    I disconnected the center last night and in speaker setup basically told the NAD that I'm running 4.0 surround. Big improvement!

    The volume did become louder all around. I raised the speaker levels to +5 dB (the NAD can go up to + 12) to compensate for the difference between sources and movie audio was better. Of course, it would help if everything was mixed in the same manner. In 4.0, Metallica's "Cunning Stunts" DVD was louder than any of the movies I put on. Its still not as loud as it is in 2-channel, but I'm getting there.

    As far as the center goes, I still have some time to return it. If it still brings the system down after I fix the speaker connections I'll upgrade to the EC35. I might trade up anyway; just did my taxes and my refund will more than cover the bigger center!
     
  12. John S

    John S Producer

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    Interesting.. I really think your center is having some issues at this point. I mean if you can rock away strong in 4.0, and them problems start when that center is connected.. Basic trouble shooting says, replace the center channel speaker.

    4.0 isn't a big step below 5.0 by the way. I mean you could repectfully run it this way if you wanted. But, I'd get a center going myself.
     
  13. JerryMa

    JerryMa Stunt Coordinator

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    John S,

    So you really think the center could cause the volume to decrease so much all around? Weird. I was thinking the speaker wire might have been the problem; I really did a number on the bare ends before I finally got them into the receiver's speaker terminals. But I guess I'll know more after I re-do the connections.

    I might upgrade to the EC35 anyway, still have almost 2 weeks to change my mind.

    Thanks much for the insight.
     
  14. John S

    John S Producer

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    A bad speaker connection can actually cause it too you know. But a blown speaker can actually effect performance overall as well.


    Just seems like going to 4.0 pretty much shaped it right into action. Pretty telling there, of what exactly I'm not sure. [​IMG]
     
  15. John Garcia

    John Garcia Executive Producer

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    Yep, that one is mixed a bit hot, but that's normal for most music/music DVDs. Cool DVD too. They tend to be mixed in a different type of environment and with slightly different intents than movies are. I think the loudest DVD I have is NIN And All That Could Have Been - DTS (full bitrate).

    Try hooking one of the mains to the center. If the problem comes back, your receiver may have a problem. If there's no problem, then the center speaker likely has a short in the x-over or a driver with a bad voice coil.
     
  16. JerryMa

    JerryMa Stunt Coordinator

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    It WAS the speaker wire!

    Finally got around to putting the bannana plugs on last night. I started with the speaker wire to the center channel. Lo and behold, I found a very thin layer of the outer coating still covering the copper wire, even after I had stripped it and attached it to the binding post.

    I removed the remaining coating, attached the bannana plug, and completed the connection. Dialogue and other sounds clearly came out of the center this time, and overall audio was fine.

    Thankfully no problems with the receiver or the center. The poor connection in the center explains the shut downs and the lousy audio.[​IMG] [​IMG]
     
  17. John S

    John S Producer

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    Just glad you got it all going.....

    Can you give performance impressions bewteen the 4.0 and 5.0?

    We had a post on here a while back, where the guy was expounding the virtues of running in 4.0 -vs- 5.0 and 5.1.....


    Thanks in advance....
     
  18. Brian L

    Brian L Cinematographer

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    Obviously you had an electrical issue, but the NAD does have a pretty big level difference between 2CH Stereo or 5.1 Direct mode and ANY of the DSP modes (EARS, DPL II, DTS, etc.).

    I have a 762 also, and noted that behavior straight away.

    I can still get sufficient volume in any mode, but when cycling through the modes, hitting Stereo will result in a pretty substantial volume jump (I have never quantified it).

    I have never gotten a conclusive answer from my NAD dealer as to why they chose to design the unit that way, but it is what it is.

    Speculation was that for whatever reason, there is some signal attenuation before going into the DSP stuff, but no one from NAD has confirmed or denied that.

    BTW, have you tried out EARS with any 2CH sources?

    I find that I prefer EARS to PL II or DTS. There appears to be a bit of EQ that happens when EARS is engaged (bit of a bass boost, maybe even what seems like a bit of loudness compensation) that is very complimentary to my system/room. EARS preserves the front sounds stage perfectly (it expands it actually), while bringing in a nice bit of ambience to the back of the room. There is no lame-ass reverb or delay added that I can perceive, just a nice expansion of the sound stage.

    NAD claims it works best with acoustic music, but I find that it works wonders with anything that I feed it.

    BGL
     
  19. JerryMa

    JerryMa Stunt Coordinator

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    Brian L: Thanks for the insight on the 762's tendencies in 2.0 vs. 5.0/5.1. I noticed the continued difference in volume even after the improvement to the center but went under the assumption that this might be normal. I haven't tried EARS yet but will. I did like Neo 6: Cinema a lot, but need to sit through a full movie to check it out for sure. I can post impressions next week.

    John S.: I can tell you that I liked 5.0 much better than 4.0. I know that some people have suggested I return the EC25 and get the 35, but I have to tell you that once I got it working properly, the EC25 was a joy to listen to. Dialogue was very crisp and clear.

    Its especially helpful to have a center in my setup -- while I'm used to the bookshelves sitting on top of my wall unit (never had a problem hearing dialogue when I watched movies in 2.0), the center, positioned a bit lower than the mains, makes the experience much more enjoyable. The dialogue is right in front of me, very easy to hear, and the fronts help with music and other sound effects and transitions. I find that 3 speakers across the front, even in my relatively small viewing area, have a definite advantage over 2. Granted, the size (bookshelves vs. floorstanders) and position of my fronts are probably factors in making the presence of a center speaker more beneficial, but I think using 3 speakers just helps the viewer appreciate and hear more of a movie's soundtrack. As an example, I put Master & Commander in and even without a sub, that movie's soundtrack is very dynamic on my system. Dialogue is clear through the center and music and sound effects fill the entire front soundstage.
     

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