Axiom Home Page Forums General Discussion Home Theater VP150 in a hole?

I was calibrating my new Axiom's using the AVIA disk. I have M60's for fronts, VP150 for a center and M22's as rear surrounds. These speakers are being run from a older Sony STR-DB940 A/V receiver. When I run the test which compares the left front with the center, it sounds as if the center is accentuating more of the upper bass than the left M60. It sounds rather like the VP150 is in a hole or something...not horrible but definitely noticeable. I was under the impression that the timbre of these speakers would be very similar especially in the higher frequencies...I have run a Real Time Analysis program on a laptop using the above tones supplied on the AVIA disk, using a cheap Sound Blaster mic and recorded the tones reproduced by the speakers. There is a noted difference in the frequency response graph between the left and the center...peaks in the upper bass from 60 to around 500 Hz or more occur in the center.

I thought it may be affected by my having the 150 on the shelf under my Sony KV36XBR800 TV. The Sanus Video stand on which the TV sits has a front center post adding support to the center of the top shelf holding the set (which weighs in at approx. 235 lbs) and therefore the speaker is two or three inches back from the front of the shelf. As an experiment, I put the 150 on top of the set and ran the AVIA test again...I noticed that the comparison between the two speakers (left and center) still has that difference of the center sounding like it is in a hole.

I performed another experiment this morning. I switched the speaker connections on the receiver between the center and the right front (making the left front and right front speakers identical...both M60's). I then ran the tone set again from AVIA comparing left front and center and the right front exhibited the same issue as the center does when the center is connected to the center's speaker connections.

Also, the standard individual level tones used to set all five speakers level also exhibits the "in a hole" effect for which ever speaker is connected to the center output...using this test, upon switching the connections (VP150 connected to the right front output), the center sounded more like it was supposed to (at least what I was expecting...more treble response) than when connected to its correct set of center speaker posts. Has anyone heard of any situations where the output to the center channel on a specific receiver was tonally different from the other speakers? Could this possibly be an issue with the signal on the AVIA disk for that specific test or an issue with the center output on the receiver?

This is something that I "can" hear...I tried recording it with the mic I had available just to see if it heard (and recorded) what I was hearing and that my mind was not "making it up...". I have no other "effects' turned on...no DSP of any kind except for the standard Dolby Digital decoding of the AVIA disk...

Anyone...anyone?

WhatFurrer

my guess is the center channel on your receiver.

i had a receiver a couple of years ago that had a defective center channel.

I second you WhatFurrer! I bought the VP150. It was my first speaker. So what was I to know. Now I have a pair of M2s (M60s on the way - factory seconds wait list). And the M2s and my center channel have a different tone between them. Thats both with the Avia disk (which I have) and using the test tone on my H/K 630. It's hard to believe no one else has this problem. Do we have something wrong with our speakers? Mine is on top of my 53" Sony, angled down. But man...I can't imagine moving it up or down would change the OBVIOUS tonal difference between ALL my speakers (surrounds included)to my VP150. What to do?

There was a thread a while back started by me that brought up the same issue. You can view it here:

http://www.axiomaudio.com/boards/showthreaded.php?Cat=&Board=HT&Number=30827&page=&view=&sb=&o=

Basically, we're wrong and the VP150 is a perfect timbre match to all the Axiom speakers. There's nothing wrong with your VP150. It's the best!! BTW, I sent mine back.

You sent yours back? As in...an accident back? Or, after you learned everything still sent it back? Thanks for the link by the way. I'm off to read it!

After I learned everything, I sent it back.

So what are you using now?

Hi Whatfurrer

Is the STRDB940 a 6.1 receiver? I know the 1070 has 2 center channel speaker outputs - one for the front center and the other for the rear center. I know it's a dumb question, but are you sure you are using the correct center channel output?

2x6spds,

The DB940 is a 5.1 receiver (circa 2000) so the center is the only center available. Wish it were 6.1 or 7.1 but I did not know then what I know now...

Regards,

WhatFurrer

NHT M5, IMHO a properly designed 3-way center that matches very well my fronts (also M5s).

WF, if I followed your experiments, even the M60 developed those upper bass/lower mid peaks when you connected the center channel output to it. I'll take some wild swings at it. Don't know the DB940 details, but I remember that many of those Sonys had graphic equalization provisions. If the DB940 is one of them, is the equalizer set to boost those frequencies? Or, if it's there, set it to reduce those peaks? If not, I don't have any idea why either Avia or the 940 would have a problem in that center channel frequency range.

JohnK,

Yes, the DB940 does have an equalization provision...the concern is that the EQ circuit was not in effect when I noticed this anomaly. I have attempted to use it to tame some of these peaks but the method in which Sony designed the EQ on this receiver gives the impression that whatever setting you set the last band to (regardless of the order) is the setting that ALL bands are now set to (unless they are currently set to 0)...for example: I set 111 Hz to -10 to tame that peak and then go to 125 to attempt to tame that one...changing 125 to -8 and then going back to 111 finds 111 at -8 not -10 as it was set before...and there is no way to look at all the bands simultaneously even on the OSD...only one band at a time and subsequently you have to contend with the issue above...so it makes it hard to try to tame it as it seems that only one band is getting the modification needed...I know I would have designed it differently...

That said, I now DO have the EQ enabled and it does sound somewhat better...I only wish I could tame more frequencies to try to make the 150 sound more like the M60's...I believe I am dealing with a receiver issue, not a speaker issue.

Anyone care to try it with a similar speaker setup with a different receiver using the AVIA disk's Pink Noise comparison of Left Front to Center under the Evaluation and Verification menu on AVIA? I'd definitely be interested in your findings...

Any other ideas are more than encouraged...Tried (in vain) to persuade the wife that we need a new receiver...so far, no go...

Keep 'em coming...

Thanks,

WhatFurrer

Tony, unless I'm mistaken, What is describing a different phenomenon than you heard. I could be misreading him, but it sounds like he has the "hole" problem if he hooks up the M22 or the M60 to his center channel output, and the VP150 sounds fine when hooked up to a different speaker terminal (ie, not the center channel one).

I was responding to Misfit, not Furrer.

WhatFur, Tony Geno, and all,

Please read my sidebar on the relationship of placement and center-channel timbral differences in the new March AxiomAudioFile newsletter.

Any problems experienced with the VP100 and VP150 in terms of timbral matching are placement related, not intrinsic differences in the VP100 or VP150 frequency responses.

And I want to stress that you not rely on amateurish RTA programs, cheap mikes, and the AVIA disc to do room measurements and try "corrections". At the least, proper room measurement is very complex and you need to start with $1,500 B&K measurement microphones (a Ph.D. in psycho-acoustics is also a help).

You want to experiment with placement of the center--certainly a shelf beneath the TV will introduce timbral differences. But the question is: using vocals, movie dialog and music, are you getting a seamless front soundstage, or are colorations noticeable and annoying? (You will always hear differences using pink noise.)

If colorations are audible with programming and dialog, then try different locations. In my experiments, it's possible to get a pleasing tonal match with the VP100, VP150, M22, M60s, and M80s by changing the center location in about 95% of rooms. Even sliding a center slightly to the left or right on top of a TV monitor may help considerably (it did in my own room), or using two centers above and below the TV.

Regards,

yep,

i still think there's a chance of a bad center out on the amp. he stated that the other speakers sounded like they were in a hole on the center out posts.

borrow someone's receiver and see what happens.

Alan,

Thank you for your comments.

In defense of my original post, my original rationalization with using an admittedly inferior mic and a less than professional RTA program was to prove to myself that I was in fact hearing some sort of anomaly. I would not begin to delude myself that I know more about the design of these speakers than yourself or Joe. In a response to an email to Joe there at Axiom, I included this information:

I performed another experiment this morning. I switched the speaker connections on the receiver between the center and the right front (making the left front and right front speakers identical). I then ran that tone set again from AVIA conparing left front and center and the right front exhibited the same issue as the center does when the center was connected to the center's speaker connections. The standard level tone set used to set all five speakers also exhibits the "in a hole" effect...Upon switching the connections (connected to the right front output), the center sounded more like it was supposed to (at least what I was expecting...more treble response) than when connected to its correct set of speaker posts.

As the VP150 did correctly reproduce the signal supplied when it was connected to another speaker output, I concede the fact that I am probably looking at a receiver problem and not an issue with the speaker or speakers. I was just concerned when the sound generated between the front and the center was not more alike especially taking into consideration that the folks at Ovation Software who make AVIA would probably use the exact same pink noise signal between the front and center for that test.

I apologize if I ruffled any feathers the wrong way...that was not my intent...just looking for answers.

With Regrets,

WhatFurrer

Be not ashamed WF! I can tell you. I've noticed tonal differences myself. To my ears the center sounds very "middie". My own word. Meaning the mids seem jacked on it compared to other speakers. This could be due to the three mids on it But to add to all this, I've used that center channel now with THREE different receivers and it's still more more "middie" than the rest. Perhaps this is just something to adjust to. Don't get me wrong. I think the center sounds good...but the highs seem to be more hidden behind the mids. Perhaps this merits more experimentation. All speakers I had were calibrated to 75 db using the Avia disk. But I did audible test prior to having the Avia disk. Anyone have any thoughts? Is it just a "get used to it thing"? I mean, I have a 53" tv. It has it's own built on stand so I can't place the speaker beneath it. Shy of having it on top and angling it down I'd have to put it on the floor or on a small stand. Having two kids...you can imagine that makes me a slight bit nervous...not to mention I don't think it would be the most attractive display seeing as my tv is black and speaker is cherry.

Thanks all...

Get used to it, if you wish. I currently have in my home the following centers: NHT M5 and an Infinity Intermezzo C5: neither of these show the off-axis tonal variation, and on axis lack of timbre match that the VP150 did compared to the M2s. The middy sound you're talking about is exactly what I noticed and it was much worse off-axis. Now if I read Alan correctly, he's saying that with voice or music you won't notice the difference. I suppose you could make that argument for a $100 center. But if I'm spending $350 on a center, I want a much better tonal match to my left and rights than the VP150 provided as well as better off-axis response. As I have stated before, I would love to see some NRC measurements of the 150, both on and off-axis out to 30 degrees to see if what I (and Misfit) hears can be measured.

I quote WF:

"As the VP150 did correctly reproduce the signal supplied when it was connected to another speaker output, I concede the fact that I am probably looking at a receiver problem and not an issue with the speaker or speakers. "

You and he are having different problems.

Out of curiousity, have you played with the positioning? Alan did a column on the centers in the latest thing which I found to be very interesting. BTW, Tony, in his column, he did not say that it's inaudible. He said it was a matter of positioning. In any case, I haven't heard the thing or your setup, so I'm not getting into it other than quoting.

I tried different positioning, in fact moving it on a stand in front of my cabinet. The basic sonic "signature" remained the same, and was nowhere near timbre matched with the M2, at least to these 50 year old ears. I was absolutely convinced I had a defective unit, but Ian said it checked out fine. The implication was that I was being influenced by my measurements (I noticed a fairly severe drop-off off-axis using pink noise) and that nothing Ian or anyone else could say was going to change my mind. I actually didn't start measuring until I noticed with my ears the timbre and off-axis issues. Finally, I was directed to several articles about pink noise that purported to show that it was not a good test for timbre (not sure why Lexicon would include it in their $9,000 processor, but what the hey) and that any speaker would show this timbre issue with pink noise. I can only repeat: not in my rather extensive "listening" experience. Out at 10 feet, drivers should blend pretty well, and if I'm hearing individual woofers and tweeters at that distance something is definitely wrong somewhere. That's the effect I heard moving off axis with the VP150. Again, I'm glad all you guys enjoy it. It just didn't work for me, and I have a very nice theater room in which many different types of speakers have worked.

I noticed everybody getting defensive and thought I should pipe in.

We're missing a big, important point here. Tony wasn't happy with the performance of his VP150 -- even with all the other reports that disagreed with his and after many explanations were made for the possible causes of his timbre issues. He didn't think the VP150 sounded as good as a $350 center channel should sound. Can we really fault him for that?

Nope.

Thanks.

I agree. Let's just hope that dead horse doesn't twitch again or we'll have to beat it some more.

Just trying to respond to a poster's concerns. Maybe it's a dead horse to you, but obviously other auditors want to keep that horse alive. If you prefer to just tell everyone who voices their concern that they've got a problem, if that makes you feel comfortable in your value systems, just say so and you guys can agree till you're silly.

/horse twitches

I am still leaning towards the VP150 (plus M60 and QS8) but I admit in my audition the VP150 I heard was a bit odd int he fact that it's gain had to be increased to *match* the other speakers in the HT setup.

Maybe that speaker is just too picky what kind of room its in, or amp its connected to, or tv it sits on top of...

Every now and then, I've read about VP150 not matching up w/ M60 or QS8. I like the fact that it was pointed out. I like to read critics on the speakers. Would there be a VP200 or VP 250 anytime soon?

Have anyone try M60 (matrixed center) + qs8 vs a M60+vp150+qs8... How much different will you get?

I think it's worth for Axiom staffs to visit Tony's house to investigate what's going on. If VP150 have problems, they can try to redesign and make a better center; if not, they can provide explanation to the confusion.

The VP150 is a different speaker than the floorstanders - lacking ports, the 6.5" woofers, and designed to lay flat on its side. Not unexpectedly, it seems to my ears to have a little warmer, chesty sound (not dissimilar to my Monitor Audio Bronze 2s) than the M60s or M3s. In my experience this difference is noticable w/ pink noise, but not at all w/ movies or concert DVDs (I listen to music in 2 channel only).

I suppose you could get a better timbre match using a couple of M2s in lieu of a single VP150, but for anyone with a wife that probably isn't an option.

If they redesigned the center w/ tweeters over mids the thing is going to be a foot tall, two feet wide, ugly as sin and difficult to place in some HTs. Again, not an option for the wife impaired. Might be nice to have as an option for some folks, however.

The off-axis "suck out" that Tony keeps mentioning is a non-factor to me, and probably to most others as well, since we tend to watch our movies from somewhere IN FRONT of the screen.

Uh oh - wait for it.

NRC measurements at 15 and 30 degrees (certainly in front of the screen) will prove or disprove this suckout. Anyone know where to find them?

Regarding the audibility of improperly timbre matched centers and lefts and rights, given the dynamic and transient nature of sound, I think you'd need some pretty poor matching speakers to be "audible". Truth be told, the vast majority of centers (even expensive ones) use an MTM arrangement. All the measurements I've seen show pretty severe suckouts at 30 and 45 degrees off axis. Then why do manufacturers continue to make them: marketability, pure and simple. As has been alluded, the wife won't allow something tall above or below the screen, hence we suffer from poor off axis response. Now I realize that the VP150 is different. It hasn't been proven to me (either by listening or measurements) that it doesn't suffer from the same poor off-axis response a traditional MTM. To me, it sounded rather lousy, chesty, the drivers didn't sound integrated, and I heard timbre changes as I moved off axis. Did I hear it with music: see above re the transient nature of sound.

I don't know if we should call it marketability, versatility, or functionality when we describe the TMMMT array of the VP150 (and similar centers). The VP150 sounds great. It can be placed in tight spaces because it is a sealed design. Your timbre-matching complaint you nullified yourself. The off-axis "suck-out" is null for me and mine (and most everyone else). So why do you persist?

I just watched "Pirates of the Caribbean" and was completely stunned and satisfied (as always) by the performance of my entire system. (Maybe increased sensitivity from the Axioms would be nice.)

I think I'm going to go analyze some pink noise now.

Mark, please be careful. The Axioms are very sensitive and comments like that will upset them!!!

I persist because the subject came up and I gave my opinion. It appears my opinion makes you uncomfortable, so I'll go. You have succeeded in chasing me away and can now continue your love fest. If it comes up again, I guess I'll just stay away. I don't want to upset or challenge your notions of what's good in center channels.

I'd rather you didn't. I enjoy reading differing opinions and hearing what else is out there. Yes, I own Axioms and like them, but that doesn't mean they are the be all and all and the perfect speaker for everyone. If they were all the other speaker makers would be out of business.

i think the vp150 performs extremely well for the price. i had a paradigm cc370 that never seemed to cut it.

i would be interested in trying another center if axiom ever made one.

there are three major stereo speakers (m22, m60, & m80) so why not go for a 3rd center?

Misfit_Toy

I have a H/K 630, VP150 and M60s.

I HAVE heard what you are talking about.
I have NOT heard or measured what Tony is talking about. (I did try, though...)

I FIXED what you are hearing on my system by changing the crossover to 100Hz. No audible differences that way. Change it to 80Hz and I can hear it.

I get the exact same results if I wire one M60 to the center channel. One M60 sounds different than the other one at 80Hz xover. I have no idea why.

Let me know what you find.

Perhaps I have overreacted, but do not innocently proclaim that you were merely giving your opinion. You were sarcastic in your first post (but I suppose you're right - after all, NHTs are the best and we're all f***ed here), and simply ignorant in another (the VP150 is far, far from "lousy").
All I'm saying is that your complaints about the VP150, even if they had some validity, don't matter to me because: at 13 feet away the VP150 covers all of my HT seating area w/out any suck-outs; and I'm not concerned with how pink noise sounds from the VP150 - only dialogue and effects.
I'm done.

BigWill is mad

Nah, it was just his turn.

I disagree. I clearly heard a can of "whup ass" being opened.

you know, they now offer that 'whup-ass' in a bottle, and rumor has it that you can get it out of a fountain machine also..

add a squirt of cherry flavor though, it has a tendency to taste like $hit..

and not to take sides, but i dont like pink noise either!!

bigjohn

Pink noise may be annoying, but it's much better than brown noise...

Maybe Bren can link us a sample of brown noise?

thank you for that peter. heard on the news yesterday there was a guy in the hospital having a wart removed from his inner thigh (sp) with an electric needle...yup, you guessed it, brown noise vapor ignited and scorched his...private parts. ouch, and yes a law suit has already been filed.

Well, I suppose this thread hijacking could still be construed as audio related.....

OK this thread went from informative to funny... either way its entertaining.

back on track...

i would like to see a center that shadows the paradigm cc570. name a price, i'll try it.