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

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.