Axiom Home Page Forums General Discussion Technical Questions Ian (or Alan), question about VP150 design/layout

That's on top of the amplifier, not the speaker.

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I have the VP150 and it's one of the best centers I have ever heard. I have the Fifth Element superbit, and that Opera scene at 'full blast' is @(^($@ incredible! Her voice, even at the highest frequencies, just sail across my living so gently and swiftly, never hitting a foul note, never sounding fatiguing or annoying. Trust me, I am EXTREMELY picky about sound.

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I also recently purchased a VP150, along with a pair of M60ti's, M3ti's, and a single QS8. Part of the reason that discussion caught my attention is because the VP150 hasn't quite lived up to my expectations. Sound from the center channel sometimes seems to have a slightly hollow or "boxy" sound to it, and maybe a slight rolloff in the upper freqencies. Dialog also seems strained at times, sometimes even to the point of slight distortion that sounds like crackling or static. Note I'm not even talking about off-axis performance here, this is from the sweet spot. The other speakers are very impressive, particularly the M60's which have given a new life to 2-channel music; so I don't think this is just a matter of me expecting too much from the Axiom speakers. The way I see it, there are three likely explanations for my disappointment:

1) My VP150 is somehow defective. Thing is, it's not obviously broken, so I don't know if it's possible for the speaker to have a defect that hurts performance without making the speaker inoperable. Also, I really don't know of any technical test or diagnostic I could use to determine this.

2) The VP150 just doesn't perform up to my expectations. On the other hand, given the price of this top center from the Axiom lineup and the fact that I'm very happy with my other Axiom speakers it seems like this center should suit my needs well. That's why when the discussion about the design of the VP150 came up on the other board it caught my attention.

3) Source Material. I suppose this is possible given that sometimes the VP150 seems to sound better than others. I would even expect this if I were just getting disappointing from analog cable TV. But that's not the case, as I'm seeing these problems with DVD's that I would consider to be reference material. You mention 5th Element Superbit; the scene where Leloo escapes from the lab and jumps off the building has always been demo material for me, as well as the scene where Gary Oldman's character demonstrates the new gun. Both of these scenes exhibit the problems I mentioned above. And the other night when we were watching Mothman prophecies there's a scene towards the end where it's totally silent except for a phone ring coming from the center channel, which had noticeable distortion/crackling. But then last night watching Disney's Atlantis the sound was very good. So I don't know if Atlantis is just a less-challenging soundtrack for the center, or do the recordings on the other two movies contain distortion?

The one thing I am sure is that this is not an issue of inadequate amplification or clipping. I'm using an Outlaw 770 amp with 200W/channel @ 8ohms (300W @ 4ohms), so it should be plenty of power considering I watch movies at 6-10db below reference level (usually 10).

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My receiver also has a 5 channel stereo option, and classical music with this on definitely sounds great out of the center. Off axis performance is also amazing. I have M22's, M3's, and VP150, and I think the VP150 has the best off axis performance of the three

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Interesting, my old Denon had 5-channel stereo, and my Rotel 1066 has 7-channel stereo. About the only thing good I can say about these modes is that they're loud. I much prefer plain old 2-channel or maybe ProLogic-2 for classical music, both of which do a better job of preservering the soundstage and imaging of the recording.

A very interesting quandry indeed.
I guess the only way to sort out the potential problem is to poll some other users with dvds and the same videos (with the same hookups as well, rca vs digital) to clarify whether these sounds can be heard with anyone else's setup.
You could also possibly switch out your Outlaw with something else to remove the receiver as a possible source of the distortion.
Of course there is always returning it to Axiom for a look see but offhand most broken drivers are relatively easy to hear and determine that a replacement driver is needed.

Can you isolate the distortion to any one particular driver or 'area' of the speaker? Or is the distortion actually 'in' the sound?

I'm planning on buying a VP150 in the next month myself and stories like this make me a tad nervous (obviously due to the $$ spent more than anything).
Let me know how things turn out.

I recently set up my new VP150. Listening to Diana Krall's DVD for the first time, I heard definite buzzing and distortion from the center channel. I took off the grill and listened, and I could isolate the sound to the right-most woofer, which was buzzing on each note from the string bass. I hadn't heard this on other DVDs but the soundtracks hadn't been as detailed.

I assumed that it was defective, and I could still send it back in my 30 days. I replaced it with my old cheap center, but after listening for a while, wanted to compare again to the VP150 - and the buzz was gone. Don't know if it was a short in the cable connection or what, but I can't hear it anymore. I think the 30 days is ending soon; hopefully the buzz won't return.

ChrisR

Chris, your experience sounds similar to mine, and I think your description of "buzzing" may be a better term for what I'm talking about when I say "crackling". Maybe it's a questionable wire connection, I'll check that when I get home.

BTW, I don't want to paint too negative a picture about this speaker, because it is better than my previous center. The occasional boxiness/boominess I mentioned is somewhat subtle, and I have a feeling that it is related to the source material, because it only seems that way occasionally. It's the distortion/crackling/buzzing that concerns me most.

PS - What's this Diana Krall DVD you mention, I've heard her name come up several times when people discuss reference/test material. Searching amazon.com I see "Live in Paris" - is this the DVD you're referring to?

jkohn,

Live in Paris is indeed the Diana Krall DVD concert, and it's excellent. The DTS mix puts you literally right on the stage... the piano is played in the surrounds, and the guitar is so ridiculously forward in the left/center you'd swear YOU were playing it.

jkohn & Chris,

I had (what I think is) the exact same symptom in my VP 100 that you describe for your 150's. It wasn't noticeable during the movies or music I had played up to that point, but was very evident during the subwoofer crossover check calibration on the S&V disc. I thought I'd broken something within my first week, but while talking with Joe V, I was able to localize the "giant mosquito buzz" to one of the woofers. He had me check for dust on the cone, and while gently pushing on the rubber "boot" surrounding the woofer, the sound miraculously went away. I was thinking it could be a short of some kind since I was able to recreate the buzz by pushing again on the boot. I pushed on the boot one final time to make the buzz go away, and all has been good for over a month now. Joe shipped me a new woofer, but I haven't installed it yet because the "buzz" hasn't returned. Somewhere online (this forum or HTF), a poster mentioned tightening the hex screws around the woofer/tweeter on his Axiom speakers as they were a bit loose. I checked mine and the screws on my center were a bit loose. I tightened them up "just to be sure", and haven't had any problems.

I'm no speaker expert, but your symptoms sounded exactly like what I experienced. I don't know if I have (or had) a short or a loose connection, but things worked out great in my case, and I continue to be blown away by the performance of my system. Good luck, and give Joe a shout if you still have problems.

lando

Lando, thanks for the little snippet of info.
After all this hubbub about buzzing, i went downstairs and played with my M60s for a bit.
Since i'm still in the auditioning stage i'm being extraordinarily thorough about scrutinizing any odd sounds before committing the actual purchase to a permanent one.

I played 2 songs, "I can see clearly now" by Holly Cole Trio and "New Age" by Tori Amos (first couple of seconds of each song has bass tones to push the lower end, esp. the Tori Amos song).
Lo and behold, there is a mild buzzing radiating from the lower woofer at each beat. It only goes away when i turn down the volume but the woofer should be able to handle that sound without any problem at the volume i was using (around 65%-75% max volume). Both woofers on the left and right speakers make the noise although the right speaker is more noticeable.
I will read through your post again and see if there is a simple fix as you mentioned but so far i'm not impressed by having to fix anything at all.
For several grand for an entire system, buzzing is NOT acceptable. I'm hoping i don't have to return these M60s before the 30 days is up because i do like alot of things about them so far.

An addendum to my last post:

I just did the screw tightening, lint looking and touch rubber tests but to no avail.
It seems after the screw tightening the buzz decreased a bit but i could not get it to go away. It only comes around with certain frequencies of lower range sound (as in the 2 previous songs mentioned).
After very gently pushing on the dust caps (not while music was playing) i did notice that the woofer cone sounds like it is hitting something behind it. The woofer cone in the left speaker did not have that same sound when gently pushed and its buzzing sound was also noticeably less (as previously mentioned in prior post).

During my close inspections I also just noticed a small flaw in the vinyl near one of the woofer edges. It almost appears as if the woofer was replaced once already, or perhaps someone had a bit of trouble getting the original woofer in there in the first place. A small chip of vinyl about an inch long around the edge of the woofer inset on the cabinet has lifted away a touch from the underlying MDF.

I'm very unhappy.

Chesseroo,

I saw your posts and feel for you about your buzzing. Again, I have little speaker knowledge so please don't take my earlier post as the best solution for anything. In my situation, the buzz in my VP100 hasn't returned, and I remain confident that I have the best system for my money. Good luck!

lando