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Discussion Starter · #1 ·
I've had my front three KL650's (part of the Klipsch THX Ultra2 system) for a few weeks now. My other speakers are a pair of Paradigm dipoles on the side and a pair of AR towers in the rear. My receiver is a Denon3300 (105watts/channel @ 8ohms; 5 channels) My room is quite large at 32x17.5x9' (4750cf).


The front three were my first step in an upgrade process that eventually will include the rest of the speakers and separate amps / pre/pro.



I have been pretty amazed at the sound. For most movies I am able to play at an average of 85db with peaks at 100db and everything sounds nice and clean. However, there have been two movies lately that when played at those volumes have given me what I think to be amp clipping. It came across as a "splat" sort of noise from the front center.


I also want to point out that I'm running 4 speakers off of the two rear channel amps. Isn't this pulling available current from the front three and hurting them even further?


My question: Is it likely that it was clipping I heard? I'm looking for some verfication that a better amp will be the solution.


I'm not terribly versed on electronics, but I know it is recommended to run these speakers with 250w / channel (despite them being very efficient) if you want the best they can offer.


Any ideas or input? Has anyone else had this happening and a better amp solved the problem? I'm open to something along the lines of a B&K 200.7 or Outlaw 7700, but was hoping to not have to for a year or so.
 

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Quote:
Originally Posted by tony123 /forum/post/16955903


I've had my front three KL650's (part of the Klipsch THX Ultra2 system) for a few weeks now. My other speakers are a pair of Paradigm dipoles on the side and a pair of AR towers in the rear. My receiver is a Denon3300 (105watts/channel @ 8ohms; 5 channels) My room is quite large at 32x17.5x9' (4750cf).


The front three were my first step in an upgrade process that eventually will include the rest of the speakers and separate amps / pre/pro.



I have been pretty amazed at the sound. For most movies I am able to play at an average of 85db with peaks at 100db and everything sounds nice and clean. However, there have been two movies lately that when played at those volumes have given me what I think to be amp clipping. It came across as a "splat" sort of noise from the front center.


I also want to point out that I'm running 4 speakers off of the two rear channel amps. Isn't this pulling available current from the front three and hurting them even further?


My question: Is it likely that it was clipping I heard? I'm looking for some verfication that a better amp will be the solution.


I'm not terribly versed on electronics, but I know it is recommended to run these speakers with 250w / channel (despite them being very efficient) if you want the best they can offer.


Any ideas or input? Has anyone else had this happening and a better amp solved the problem? I'm open to something along the lines of a B&K 200.7 or Outlaw 7700, but was hoping to not have to for a year or so.

Sounds like your'e fixing to burn out 2 rear channel amps running them that way. Taxing power supply and amps, while dropping down to lower ohms than the equipment can handle. Why are you running 4 speakers off 2 rear amps? Your'e trying to make a 5 channel receiver into a 7.1. Only bad things can happen. Disconnect 2 of those speakers and run system as designed until you can get a 7.1 receiver. No use in ruining a good receiver and set of speakers.
 

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Discussion Starter · #3 ·
Thanks Phantom. I'll do that.


Does the fact that I was doing that have a direct relation to the clipping in the front channel?
 

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Discussion Starter · #4 ·
I'd like to add, that the menu in the reciver allows for either Speakers "A" or "B" or "A&B". If Denon gave this as an option I assumed it was.
 

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Quote:
Originally Posted by tony123 /forum/post/16955903


I have been pretty amazed at the sound. For most movies I am able to play at an average of 85db with peaks at 100db and everything sounds nice and clean. However, there have been two movies lately that when played at those volumes have given me what I think to be amp clipping. It came across as a "splat" sort of noise from the front center.


I also want to point out that I'm running 4 speakers off of the two rear channel amps. Isn't this pulling available current from the front three and hurting them even further?


My question: Is it likely that it was clipping I heard? I'm looking for some verfication that a better amp will be the solution.


I'm not terribly versed on electronics, but I know it is recommended to run these speakers with 250w / channel (despite them being very efficient) if you want the best they can offer.


Any ideas or input? Has anyone else had this happening and a better amp solved the problem? I'm open to something along the lines of a B&K 200.7 or Outlaw 7700, but was hoping to not have to for a year or so.

If you have two pairs of speakers hooked up to the same set of speaker terminals on the AVR, then you have them wired in parallel and this halves the resistance of the speakers. If you had 8 ohm speakers that would mean that they are now effectively 4 ohm speakers.


But wait! That's not all! It gets worse!


The impedance of your speakers varies over the frequency range due to the characteristics of the drivers and the crossover network. So it almost certainly dips down to at least 6 or 4 ohms at some frequencies. Which means that you are presenting your AVR with loads of 2-3 ohms.


Now most AVRs will not handle speakers of 4 ohms or less well and you are likely going significantly below that. In fact only the most expensive of standalone amps will handle 2 ohm loads well. So it is an extremely bad idea to be doing this with an AVR.


As to clipping I would expect so, but it is odd that you'd get the noise from the center channel. Of course most AVRs are a "pooled" power design. So it could be clipping the center channel when attempting to power your surrounds and yes you are lowering the power available to the fronts/center.


Also given that you are sending the same information to both sets of rear speakers. This is accomplishing little other than to give you somewhat higher SPLs from them (about 3db IIRC).


If you plan to upgrade to a Klipsch set, they are typically extremely efficient speakers and don't generally require lots of power. In fact they often require 1/8th the power that other speakers need (IE. 100 wpc = 800 wpc). So you may be better off simply upgrading to an AVR with a 7 channel amp set up.


If you still do want an amp. Emotiva makes the UPA-7 ($700 - 7x125wpc), XPA-5 ($600, 3x200wpc). and XPA-5 ($800, 5x200wpc).


The UPA can handle 7 channels on it's own, the XPA-3/5 would need either an AVR or some additional amps to hit 7 channels.
 

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I would have to agree, remove the second set of rear speakers. If you must have a 7.1 then upgrade to a 7.1 receiver. Try this first. The A/b seems to be for just a second zone output. Does the receiver have 7 outputs?
 

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Quote:
Originally Posted by tony123 /forum/post/16956087


I'd like to add, that the menu in the reciver allows for either Speakers "A" or "B" or "A&B". If Denon gave this as an option I assumed it was.

This option is given to you in order to use additional speakers in another zone or room as you would have it. It is not meant to be run in parallel as you have it doing. Hope this helps and its as the Bobcat says your'e fixing to fry you current receiver. Luckily it hasn't happened yet, but it could at any time.
 

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Discussion Starter · #8 ·
All speakers were wired to there own terminals. There are 7 terminals and only 5 amps. The menu gives you the option of A&B.
 

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Discussion Starter · #9 ·
The extra pair of speakers are already unhooked.
 

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Quote:
Originally Posted by tony123 /forum/post/16956238


All speakers were wired to there own terminals. There are 7 terminals and only 5 amps. The menu gives you the option of A&B.

As Bigbare said. The A/B connections are for driving speakers in separate areas. So that you could have your living room 5.1 system and a pair of speakers out on the patio for parties or something like that. Not for running all the speakers at the same time or for a 7.1 set up.


You are NOT supposed to be operating the 2 B "zone" speakers and the 5 A "zone" speakers at the same time for the reasons I listed.
 

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Quote:
Originally Posted by tony123 /forum/post/16956243


The extra pair of speakers are already unhooked.

Good for you. If the 3300 has an EQ program you need to re-run it now, so the receiver can perform as it should. You should no longer have that sound coming from the center as before. Enjoy.
 

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I had a Denon 3805 until last week. On it you had the option of running two pairs of side surround speakers. I believe the idea behind this was that were one so inclined you could run either a pair of dipoles for side surround or a pair on regular speakers and then choose which pair you wanted to listen to.


Does your 3300 have this option? If so you just need to choose which pair to run as side surround.
 

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Discussion Starter · #14 ·
I understand everything stated, but am still confused as to why the receiver menu would allow for a setting that was not to be used? Also, to point out, that both sets of speakers were getting a surround signal only (wouldn't work well in a 2nd zone application). I also find no setting that would send surround speakers B a full range signal.


The owners manual calls the setting of A+B "multi surround mode". Whatever the heck that is?


Denophile, I'm hoping it wasn't the speakers excursion limits, as these are Ultra2 certified and designed to provide more sound than I was asking for. Does an underpowered amp cause a speaker to hit this limit sooner than it would with adequate power?
 

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Quote:
Originally Posted by tony123 /forum/post/16956433


I understand everything stated, but am still confused as to why the receiver menu would allow for a setting that was not to be used? Also, to point out, that both sets of speakers were getting a surround signal only (wouldn't work well in a 2nd zone application). I also find no setting that would send surround speakers B a full range signal.


The owners manual calls the setting of A+B "multi surround mode". Whatever the heck that is?


Denophile, I'm hoping it wasn't the speakers excursion limits, as these are Ultra2 certified and designed to provide more sound than I was asking for. Does an underpowered amp cause a speaker to hit this limit sooner than it would with adequate power?

There's an explanation of this A/B stuff for a 7.1 denon here.

http://www.avsforum.com/avs-vb/showthread.php?t=1148072
 

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Quote:
Originally Posted by tony123 /forum/post/16956433



Denophile, I'm hoping it wasn't the speakers excursion limits, as these are Ultra2 certified and designed to provide more sound than I was asking for. Does an underpowered amp cause a speaker to hit this limit sooner than it would with adequate power?

thx doesnt mean much--i think just that it can hit thx reference level and peaks at a particular distance maybe someobne more knowledgable source casn say more. i also think a clipped signal can cause abberration in cone mechanics--again mabe an engineer type could commemt...
 

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Quote:
Originally Posted by Denophile /forum/post/16957011


thx doesnt mean much--i think just that it can hit thx reference level and peaks at a particular distance maybe someobne more knowledgable source casn say more. i also think a clipped signal can cause abberration in cone mechanics--again mabe an engineer type could commemt...

Ultra 2 does mean it is rated down to 3.2 ohms or something like that.
 

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Discussion Starter · #18 ·
I don't hang my hat on THX either, but it does mean that they are designed to perform at higher levels than I was using when the "splat" happened. I think that makes it easier to point the finger at the AVR, especially with my abusive wiring.
 

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As great as the 3800 was, it is now outdated. The 3808 can be had cheaply and would give you HDMI connections to take full advantage of lossless audio like Dolby True HD and DTS HD Master Audio. Room correction is also a huge benefit to going with a newer AVR. Good luck!
 

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Quote:
Originally Posted by TPnBobcats /forum/post/16957172


Ultra 2 does mean it is rated down to 3.2 ohms or something like that.

The speakers are Ultra2, not the amp.


Any time I've pushed a receiver too hard, it turned itself off.
 
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