Axiom Home Page Forums General Discussion Advice from Axiom Owners Timbre matching fronts with VP150 center

I've had my VP150 paired with M22tis for almost a month now. I've noticed that the M22s don't seem to timbre match with the VP150 as closely as I would have expected, given that they have the same drivers. (I'm wondering if the difference in ohms -- 6ohms for the 150 and 8 ohms for the M22s -- has anything to do with that).

I really like the VP150 and would like to keep it. Does anyone know if the M50ti is a better match in timbre with the 150? (or maybe the M60ti?) And/or would it really make a difference?

I've also seen posts where some users have put an M22ti on its side as the center to have three identical speakers across the front. Has anyone tried going the opposite route and using three VP150s across the front?

btw, my room is 28'long x 12'wide x 7.5' high (basement) and I sit about 12-15' from speakers/screen

Just offhand i have yet to hear anyone say that the VP150 does not timbre match with the M22s. It is rather hard not to be timbre matched since as you say, they do use all the same drivers, cabinet style and materials.

Could you elaborate on exactly why you think this is so? What is it that you hear?

There are a couple of possibilities, the first of which comes to mind is speaker placement, tweeter heights and separation distances. I would tweak some more with this.
Second possibility is that one of the drivers/tweeters from your speakers may not be working possibly causing a lopsided loss of sound. I would check over each driver while sound is playing just to be sure all drivers/tweeters are firing.

Other posters may have more suggestions.

I think a test is in order!

Try placing the VP150 on its end right next to one of your M22s. Then do a pink-noise test on the L,C,R channels. I've found that pink noise is very revealing of timbre. Placing the VP150 in the same location as your M22 should minimize the rooms effects on the perceived sound.

When I initially set up my system with the Avia disk, I temporarily placed the 3 fronts next to each other, but the center was on its side. I just tried placing the center upright and its the same thing... the pink noise comes out of the M22s sounding a bit 'brighter' than the 150. Note that I also verified that all drivers are firing.

I second comments by chess and Peter. I understand that the VP150 is not designed to correct for the “extended baffle” effects when placed directly on a large RPTV. That alone may well be the cause for the perceived timbre mismatch, which would be corrected by slightly rearranging the center channel placement and directions. Also, I would ask you whether your left and right M22’s are really well timber matched with each other. In fact, my L/R fronts do not sound perfectly timbre matched, obviously due to the speaker-room interactions. This was further corroborated when I bought the Pioneer 45TX receiver; the auto-MCACC equalization feature in fact always results in very different EQ parameters between the L/R fronts and between L/R surrounds. Some EQ bands exhibit up to 4-5dB mismatches.

Bottomline: Don’t underestimate the effects of the room, the “forgotten component” as Alan calls it.

I have to say that ever since I got my m22's and vp150, i've been disappointed with the timbre matching, just like psycho. The m22's seem to have a spike around the 5khz range(sounds brighter) while the 150 seems to spike around the 1-2khz range(sounding heavier and muddier). I'm not sure about the accuracy of my frequency estimate, but the point is both speakers seem to emphasize different frequencies, with the m22 being the more neutral speaker.

Some things to try for better timbre matching would be to place all the speakers the same distance from the wall. Make sure the 150 is angled directly towards ear level and push the 150 as much over the top edge of your tv screen as you can, somewhat reducing the extended baffle effects.

I also experimented with the amount of polyfill inside my 150. I actually took some out since another 150 I had for a short time had much less fill in it. Mine was filled almost completely. To me it sounds better and more closely matched to my 22's without as much fill. It seems to be less muddy. I'm not suggesting you do this, but it's a harmless experiment to try.

In reply to:

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I also experimented with the amount of polyfill inside my 150. I actually took some out since another 150 I had for a short time had much less fill in it. Mine was filled almost completely.

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Now, THAT is very interesting. Do you think (or have you asked Axiom if) it reflects a quiet design update to the VP150 by Ian? When did you receive those two VP150's? -- I mean, were they likely produced at very different times?

Not that I have complaints on the sound quality of my VP150, but the curious bug in me now wants to know how "filled" mine is!

I might as well chime in here too. I always noticed that my M22's and VP150 did not sound the same either. I never really noticed it while watching a movie, so it didn't really bother me. I only really noticed it when setting my levels. (with my trust Rat Shack meter) They sounded very different with pink noise.

I don't think the difference is quite as noticable with my new M60's. I'll check it out, and try some of the placement "tweaks" you mentioned.

sushi,

The 150 that was filled much less than mine was most likely produced earlier. I'm pretty sure the serial number in the back was vp151, something along those lines, but I know it wasn't vp150se like my current one. Also, it weighed much less, around 19lbs while mine weighs somewhere around 29lbs. Marc at the audioshop can verify this as well since he's shipped many and noticed this change too.

The other noticeable change was that the midrange/bass drivers had a larger cone area while the dustcap was smaller than the drivers in mine, which I believe is the current production model.

When I hooked the two up and compared, the one with less filling sounded less muddy, maybe a tad hollow? My memory of the comparison is a but hazy. But ultimately I wasn't happy with the way my 150 colored dialogue by sounding heavy and muddy, so I decided to take some of the fill out to experiment since the other 150 had less. I basically took out the polyfill behind the two tweeters and I like the results.

Very interesting! That's a huge difference in weight, too. Alan, any comments from you?