# Center Channel Graph. Next?



## Matteo (Jul 12, 2006)

Hello,
I am trying to make sure each individual speaker is looking as good as it can before combining all of them together. I took a measurement of my front, center speaker and this was the response. It looks like it drops off pretty dramatically on the higher end, but I don't know what to expect. Just want to get it sounding as perfect as possible. 
What are you opinions on the graph? What else should I measure? Any other suggestions are great also. Thanks.

matteo


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## tonyvdb (Sep 5, 2007)

What SPL meter or mic are you using? Does your receiver have auto room correction?


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## Matteo (Jul 12, 2006)

I am using ECM 8000 mic with an MAudio ext. card, but use a radio shack spl to calibrate. I have the Sherwood R972, which uses the Trinnov EQ. I started messing with the EQ settings. The "natural" setting "gives a modest boost below 200Hz and a slight cut above 10Hz. Looking at the graph, it does cut it (blue-green graph). The green graph is another EQ setting. It doesn't look like they are helping much. 

Edit: scratch the above. trying to load the pics, but it is saying they are too large. I have not changed any settings and the first ones loaded fine. I will play around and try to load them. The graphs are flatter, but do cut off more at the higher frequencies.


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## tonyvdb (Sep 5, 2007)

I would go ahead with the Trinnov EQ as that will correct most of the peaks or dips better than you can do manually unless you have external EQs and amps. Take readings from as many positions as it allows you to to the the best results even if you take more than one reading in the same spot.


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## Matteo (Jul 12, 2006)

Should I be concerned about the dip at the top end? Is that fairly normal for a speaker?


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## tonyvdb (Sep 5, 2007)

I have a feeling that that dip is just the room response and will be corrected once the Trinnov eq is done. Did you have the ECM8000 pointed up or at the speaker?


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## Wayne A. Pflughaupt (Apr 13, 2006)

Matteo said:


> Edit: trying to load the pics, but it is saying they are too large.


Save them as 800 or smaller jpg. 800 is the largest you can upload to our server.

Regards,
Wayne


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## Matteo (Jul 12, 2006)

I was trying to load the Mdat files, not the jpeg files, duh. Anyway, here are some of the graphs in different EQ modes. It is strange, when I try to set the Trinnov for the highest setting, the 3d mapping, I get very little volume out of my speaker. So I can't take measurements using the mode I typically listen to movies in. Weird. I tried different modes like multichannel, NEO and Dolby, but I still get very little volume. 
Also, here is a pic of my right speaker for comparison. 
The center channel is built into a cabinet behind my sound screen. I have the entire back wall behind the screen covered in insulation.


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## Matteo (Jul 12, 2006)

Are there any way to label the pics? Here is a pic of my left speaker also


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## tonyvdb (Sep 5, 2007)

I have never personally used the Trinnov eq so I dont really know about how it works but they usually fix the output level and it automatically adjusts the level so it is at 75db. are you using the mic that came with the receiver?


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## Matteo (Jul 12, 2006)

No, I am using the ecm8000 mic, pointed almost at the ceiling.


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## Wayne A. Pflughaupt (Apr 13, 2006)

What calibration file are you using?

Regards,
Wayne


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## Wayne A. Pflughaupt (Apr 13, 2006)

Matteo said:


> Are there any way to label the pics? Here is a pic of my left speaker also


I just label them manually when I upload the graphs - see this post for an example.

Regards,
Wayne


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## laser188139 (Sep 19, 2009)

Matteo said:


> Are there any way to label the pics? Here is a pic of my left speaker also


What you have not yet discovered is that, after you attach the image to your message, when you have the cursor inserted in your message text and then click on the paperclip button at the top, it gives you the choice to insert a reference to the attached image at that point in your comments. Then you can create captions like the one in the link Wayne offered. 

Bill


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## glaufman (Nov 25, 2007)

If you're using our generic cal file for the ECM, it was made with the mic horizontal, not pointed at the ceiling. So In this configuration, it would be natural to see some rolloff of the highs, and each ECM will show this differently. Only other way to correct for this would be to get a cal file custom created for your particular ECM.

Also, is it possible the screen the speaker is behind (if I read this correctly) is rolling off the highs?


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## Matteo (Jul 12, 2006)

I know I loaded a cal file for the mic, not sure which one it is. I took measurements with and without the screen, the ones I posted are without the screen, but they looked almost identical. 
I was able to get the full EQ working, not sure what was happening. Here is a full frequency graph. It doesn't look horrible, but still has a high-end roll off. This is with my three mains and sub.


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## glaufman (Nov 25, 2007)

It would help a little if you would post each plot on the same scale to make comparisons easier.
What speakers are these?


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## Matteo (Jul 12, 2006)

The speakers are Atlantic Technology 8200's. I am using the same model for left, center and right and have the center (L/R speaker) placed vertical. Sorry about the scale change. I wanted to show the entire response and the one from 100-30k just slipped in. It really sounds good, but I have always been a fan of the +3dB on the center channel, and it is just a little quieter, or softer than I typically like. With Trinnov, you can't manually adjust anything if you are using the EQ, at least not that I am aware of. I think if I could make the center a little hotter, I would be very, very happy.


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## wackii (Jul 13, 2006)

Matteo said:


> The speakers are Atlantic Technology 8200's. I am using the same model for left, center and right and have the center (L/R speaker) placed vertical. Sorry about the scale change. I wanted to show the entire response and the one from 100-30k just slipped in. It really sounds good, but I have always been a fan of the +3dB on the center channel, and it is just a little quieter, or softer than I typically like. With Trinnov, you can't manually adjust anything if you are using the EQ, at least not that I am aware of. I think if I could make the center a little hotter, I would be very, very happy.


Matteo, I've just manually EQ all my speakers a few days ago. Maybe the reason why you like your center speaker to be a little hotter cuz' of the drop off at 10khz - 20khz region. I'm not familiar with your receiver, but can you turn off the Trinnov EQ and try to manually eq that yourself? You might like how it sounds manually EQ it. I turned off Audyssey on my Marantz receiver and run it manually... I just like it better this way... I can hear the speech much better than with Audyssey on. I use REW to compare the two EQ methods. It shows that my manual EQ is a little flatter than the Audyssey. The only down side is that I have to measure six locations and average them. It's a lot of work but I'm the type of guy that like to tweak my system  I must have like 50 graphs on that day. Enough blah blah from me... Give it a try, you might like it. 

Al,


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## glaufman (Nov 25, 2007)

What are your sweep parameters (start, stop, length, etc)? WRT the mic cal, the question really is whether you used our generic one or one that was custom made and came with the mic?


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## Matteo (Jul 12, 2006)

Used a downloaded cal file. I got it a year or so back, so I don't remember where, but probably a link on this site. 
I did play with the manual settings, and yes, it does help the center, but I lose a lot by doing so. The Trinnov really does a great job of everything else. The walls in my room disappear, the surround is wonderful and the imaging is superb. I need to try a few more movies as well. Some scenes are a lot better than others. I might unhook my Onkyo from the other room and switch for awhile, just to see the difference, but that is a lot of work. LOTS of work. ugh. 
I'll keep playing around. I switched speakers, just to make sure it wasn't the speaker itself, and it did the same thing: a little muffled, perhaps like they are talking through a can. I also pulled the speaker out from the cabinet to make sure that wasn't it and it didn't change it. 
Am I assuming correctly that my room could not be the cause of the dip and that it is either my measuring technique or my settings on the receiver. Also, I am pretty sure the 8200's are up to the task. 
Here is a review of them with a measurement of them at the bottom. 

http://www.atlantictechnology.com/upload/PDFs/reviews/current/8200ereview_ht.pdf

If you have any ideas, I'd love to hear them and I do appreciate those of you who have replied. Thanks.
Matteo


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## glaufman (Nov 25, 2007)

Well, it sounds like you used the generic cal file. Compared to that file, the mic pointing up at the ceiling would be expected to show some HF rolloff, but not necessarily that extreme. BUT, your particular mic COULD be adding to that with an HF rolloff of it's own. Just conjecture on my part.
You c an try scanning with the mic pointing at the speakers, even close to the speakers...
You can try scanning someone else's system/room, and see if you get the same HF response...
You can try scanning the output of your preamp...
I wouldn't think a room would do that, but I wouldn't rule it out either.


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## Matteo (Jul 12, 2006)

Well good news. After playing with my Sherwood for a few days, I noticed the RCA output for the right channel was distorting. It sounded like a blown tweeter, or maybe a "crackling" sound. At first I thought it was my speaker, but after ruling out everything else(external amp, cords, source), it came down to the receiver. I know this sounds bad, but it gets better. I contacted Sherwood and they had me reset the receiver. That fixed the distortion. Next, I used Trinnov to EQ, and it sounded completely different than the first round of EQ. The surrounds and everything still sounded wonderful, but now the center channel sounds like it should, crisp and clear. I really love it. So, a bid of bad luck led to the eventual fix to my problem. I have not tried more frequency graphs. Hope to do that later. Regardless, it sounds great, and that is what matters most. Thanks for the thoughts.

matteo


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