Need Rear Channel Opinions/Help [Archive] - Audio & Video Forums


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01-11-2008, 10:14 AM
I recently purchased Definitive Tech 7004s (terrific) for my mains. I am considering either Polk FXi5 or Definitive BP2X for rear. Any comments or opinions appreciated...thanks.

01-11-2008, 10:47 AM
If using rears for HT use then spend as little money as possible. Your sub, mains and center channel are whats important.

01-22-2008, 12:38 AM
No offense intended but I highly disagree with the above post that surround speakers are not important.

They are equally important for music and HT. All 5 speakers (or 7) work together to produce a homgenous envelopingly smooth surround soundstage in an ideal system. This can only be accomplished to the highest degree if all speakers are from the exact same brand and usually the same series. This means, at the least, they have the exact same tweeter and preferably the same midrange giving them all the same voicing characteristics. Having smaller surrounds is certainly acceptable with the proper sub settings.

The perfect system has 5 or 7 exactly identical speakers. This is rarely practical except with smaller bookshelf or satelite and sub systems. Those who mix and match speakers of different brands for the mains, center and surrounds make a fundamental mistake. The difference is clearly audible. The sub can be of any brand as long as it is of top quality.

Please don't skimp on the surround speakers. I am not that familiar with the Def Tech line but look to make sure the tweeter and mids in the BP2X are identical or almost to your fronts. The center channel should also have the same drivers. Call Def Tech on the phone to get a recommendation.


01-22-2008, 11:07 AM
It can be important in some cases to match the surrounds with the front channels. I think this is not a huge concern with movies, but if you listen to multi-channel audio it is a much bigger deal.

Ideally, you would want the speakers to all be identical. Anything less is a tradeoff due to space or budget concerns. I think for HT it is a tradeoff that can be lived with. Just make sure you buy quality and match them as much as possible (tweeter especially). Level matching with the AVR can help.

01-22-2008, 02:25 PM
Hi Zepman1,

Not to beat a dead horse here but this thread touches on what I think is a common misconception. That certain speakers and sometimes electronics are described as being better for music than home theater and visa versa. The presumption is that movies are filled in the rear channels with sound effects and the rear speakers are therefore not that important as they are with music. The quality of the all speakers in both music and HT are of equal importance in my opinion.

This expanation from the Axiom Audio website states it a lot clearer and shorter than I can:

....."Q.I've been told that there are subwoofers and speakers that are “good for home theater” and others that are “great for music.” Can you explain which one the Axiom subs are best suited to, and why?
A. A smooth, accurate and transparent loudspeaker or subwoofer doesn't distinguish between different types of sound. It does not know which electrical signals are reaching it from the amplifier, DVD player, CD player or turntable, whether it's the sound of a summer rain storm on a movie soundtrack, an explosion in a war picture, the dynamic musical shadings of a full orchestra, or the full-bore impact of a rock band. The final test of a transparent loudspeaker is always accuracy, and musical realism, and that includes subwoofers. A neutral loudspeaker accurately reproduces the audio signals, no matter what the source, so a subwoofer capable of realistic reproduction of a jazz acoustic bass or pipe organ will do just as good a job with explosions and dinosaur footfalls. Likewise, the delicate timbre of male and female vocals and movie dialog or even the sounds of a helicopter flying overhead will be handled with equal aplomb by an accurate speaker."

RR6 :p

01-22-2008, 10:57 PM
I prefer bi-pole/dipole operation for the rear channels. It presents a more diffuse soundfield which is excellent in this application, because a direct radiation pattern can lead to the annoying problem of the rear channels becoming too focused, and interfering with the primary front/center image. For movies it doesn't matter quite so much, but for multi-channel music the bi/di-polar radition pattern is much more effective for seamlessly melding with the front and center channels, I find.

Polk, for example, offer bi/di-polar rear channel speakers. Having said this, I do use KEF Reference 107s (direct radiating) for the surround channels, and Polk Audio FX/1000 (bi-polar di-polar radiating) for the rear (directly behind) surrounds. RoadRunner is right - same brand has the real advantage of matched timbres, although timbre matching, while not easy, is possible with different brands also. I do use KEFs as my main front speakers. so the KEF Reference 107s are an ideal match for surround.

01-23-2008, 01:30 AM
I actually have surround speakers that cost more than my front speakers. Axiom calls the design "quadpolar." They happen to have the exact same titanium tweeters (2 each) as in my fronts and 2 each slightly smaller midrange/bass drivers (4" versus 5-1/4") of the exact same aluminum construction. They also have the non parallel sides like the fronts to break up standing waves.

Their explanation is very informative:

......." Axiom’s founder and designer Ian Colquhoun decided to elaborate even further on the dipole/bipole surround concept, producing a "quadpole" design. He placed woofers firing upwards and downwards on the top and bottom panels, respectively, of Axiom’s QS4 and QS8 surround speakers. Then he used a pair of tweeters firing at 45-degree angles, on angled portions of the speaker baffle. The result is a multidirectional-radiating surround speaker firing in four different directions (hence the moniker "quadpolar"). However, in the Axiom design, all drivers operate in phase. When this speaker is side-wall mounted, the net effect is both an ambient wash of atmospheric sound that mimics what’s heard in large cinemas, coupled with higher-frequency directional acuity provided by each QS speaker’s dual tweeters firing at diagonal angles across the listening area. In many applications, this is an ideal state of affairs, because it preserves ambient and directional effects for Dolby Digital/dts movie soundtrack playback while yielding fairly precise directional information for multichannel DVD-Audio or Super Audio CD (SACD) music listening, with an added ambient component to enhance musical "hall" sound."

For a more detailed study of surround speakers by Axiom click here:

All of this results in a surround experience in my listening room that I feel is a superior compromise for both music and HT. Their front speakers are very good indead. Their surrounds are superb. They were the deciding factor in my choosing the Axiom system.