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weak center image

1049 Views 7 Replies 4 Participants Last post by  dsh2009
hi all,

dowloaded and played around with some of the Sheffield discs yesterday - thanks to everyone who has so graciously posted them. in doing so i did find one thing that bothered me about my system's response.

when playing the tracks on the Imaging and Setup Disc 102, i noticed that on the tracks with drums moving from left to right, while my center image is right where i want it just above the center of the dashboard, it's weak, or lower in perceived db to me and noticeably so, and also slightly diffuse, not as focused as it is as it moves to the left and right.

is this a phase thing? i tuned the system with an RTA and parametric EQ/TA and response is relatively flat (some lower end boost and some roll-off at the very top end as per what i like).

don't get me wrong the system sounds great - i just now feel like it could be a lot better if can fix this center image thing.

thanks in advance for all tips, tricks, or advice here!

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did you do any amplitude adjustment on the left side?
What I do is:
mute everything but the mids and play a 300Hz (it really dosn't matter as long as its in the frequency range of the mids) test tone.
Play with TA till the beep is dead center.
Then mute everything but the tweeters and play a 3kHz (again, it really dosn't matter as long as its in the frequency range of the tweeters)
Play with TA till the beep is dead center.
Un-mute mids & enjoy good sound.
hey guys thanks for responding.

BigRed: last night i didn;t do ANY adjustment, i simply noticed what i percieved as a weak or quiet center image and wondered how to approach fixing it. when i did the initial tuning, over a year ago, i'm sure that there were several adjustments of levels up front (i am running active, Focal Polyglass 6/5" in doors and tweets in sails)

Megalo: i like your TA adjustment idea and think i might give that a try - i had set up the TA using distance measurement when i initally set the thing up some time ago, and then tweaked that a tiny bit by ear in order to get the sub to sound like it is up front and not behind me.

Megalo, that is a really cool tip. Watching this thread with great interest. I always go too crazy with the T/A and screw everything up.

Thanks. I'm sure someone will chime in and say "That's a good way to burn your voice coils!".
You do have to be careful and not get crazy with the volume.

I've tried the tape measure method and never got great results. There are too many variables with reflective surfaces and such.

I tried to "freestyle" it with music, but it can be hard. Maybe if you use a simple/long vocal track.

This way is just simple to me. I use a 300Hz sine wave because its right in the middle of the vocal range per Wikipedia. It seems to put the vocals right on the center of my dash.
I have a signal generator I can plug into the rca in, I definitely wouldn't hammer the volume.

Thanks again.
ya i'm going to use the signal gen on my laptop TrueRTA rig for this.

i think i'll have to go a bit higher than 3k for the tweets though since that's right around where i have them crossed over.

and ya, the tape measure thing seems just too easy to f**k up, looking forward to trying your method, perhaps even get to it tonight.

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