Axiom Home Page Forums General Discussion Home Theater Question about cables!

Hate to spin off many new threads, so I continue here with a new question for y'all...

Okay, so the QS8 (QS4) has this interesting dipole/bipole configuration, with the two tweeters firing sideways out of phase from each other and the woofers in-phase to each other firing up and down, right? This obviously makes the QS8 functionally asymmetrical, i.e., when you face a QS8, the tweeter either on the right side or the left side can be in-phase to the woofers.

So, my burning questions are:

(1) When we order the QS8 as a pair, is each unit within the pair wired mirror-image to the other? Or are they always wired identically? I know that, for example, Boston Acoustics' dipolar surrounds are wired mirror-image to each other when you order them as a pair. Does Axiom do the same?

(2) If my pair is indeed wired mirror-image to each other, how can I tell which is which? And in this case, if they are to be side-wall mounted in a symmetrical fashion, which tweeters -- i.e., the rear-firing ones or the front-firing ones -- should usually be out-of-phase from the rest of the system? (similarly, if they are to be back-wall mounted, should the outward or inward firing tweeters be out-of-phase from the rest?)

(3) If all QS8's are wired identically at the Axiom factory, then the system will not be truly symmetrical even if all speakers are placed symmetrically. Is it worth the trouble of flipping the tweeter phases on one of my QS8's in order to get them functionally mirror-image to each other? Has anybody here ever cared about this?


I know I will have to experiment eventually, but I would like to have some comments from you guys first...!

Incidentally, after some initial experiments, my current plan is to mount the QS8's on the back wall, at about 7' high (the ceiling is 10' high) and approximately 15' from each other, so that they are quite sideways rather than rearways from the listening position.

Thanks!


PS: oh, btw, my pair of the QS8 surely have the same serial number.

I have to say that I am impressed with the Hsu VTF-3!

I was listening to Saint-Saens "Organ" symphony (Munch/Boston Symphony) this afternoon, while playing around with various matrix-surround effects on my new 5.1 system. Then came the famous pianissimo pedal tone in the slow second movement -- the low C with a fundamental at 16.3Hz. I, for the first time, realized that this recording contained such a clean bass. In fact, even before I "heard" it, several of the family photos and posters hung on the wall started to rattle...!

And I repeat, it is really a very very soft, pianissimo pedal tone that did this much damage.

Careful, sushi; if the Saint-Saens 3rd had that much effect, the opening of Also Sprach Zarathustra might completely collapse the walls!

In reply to:

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Okay, so the QS8 (QS4) has this interesting dipole/bipole configuration, with the two tweeters firing sideways out of phase from each other and the woofers in-phase to each other firing up and down, right?

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Alan has given me the answer via email. The answer is NO, the tweeters on the QS's are wired in-phase. I do not know where the heck I got the impression above; I believe that I have read a published professional review that states (mistakingly) that the QS8 is a hybrid dipole/bipole...

Anyway, one less thing to worry about, and it is time to enjoy more music!!!

You're not alone. I was under the exact same impression. Is it the woofer that's out of phase? Or are all cones in phase?

According to Alan, there is no dipole elements in the QS surrounds. Both tweeters and both woofers are wired in-phase. I suppose that there is a significant phase shift between the tweeters and woofers due to the crossover circuit.

In reply to:

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I believe that I have read a published professional review that states (mistakingly) that the QS8 is a hybrid dipole/bipole...

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Found the culprit (or at least one of them)!!! LOL

From Home Theater & Sound equipment review:

Since the Axiom Epic 80 system is of comparable size to my Paradigm system, my starting point for set up was easy, since I just replaced my existing speakers with the Axioms. I tweaked the toe-in of the M80Tis slightly, and moved them forward into the room to alleviate some boominess. A little care should be used when setting up the M80Tis or the midrange may sound a little forward. I stand-mounted the QS8 surround speakers, minimizing the amount the downward-firing woofer was impeded by the stand. For a permanent QS8 installation, I would recommend wall mounting or purchasing from Axiom the stands that will allow the bottom-firing woofer to breathe. The null point between the two tweeters fired directly at my listening seat. The VP150 sat in the usual location above my 32" TV. I raised the rear of the speaker slightly so that it would fire more directly at my listening seat.

This reviewer obviously misunderstood that the QS8's tweeters were in a dipole configuration... [sigh]

Perhaps what he meant about the 'null point' was the space between the two tweeter on the QSx.
I know someone on the forums had asked once before if they were supposed to setup the QSx speaker with one tweeter pointed directly at the listening area while the other tweeter would point elsewhere.

It seems that Onkyo just released in Japan a new crop of 6.1 receivers with the video upconversion feature. I believe that they will be released in the US sooner or later; the top model in this group should sell for around US$600 street. So, if anybody is interested in a modestly priced receiver with video upconversion, stay tuned with Onkyo.