Odd behavior of one center channel with my JBL 590s..any ideas?

[GabrielPhoto]

Hi!
So I have been testing MANY center channels for my JBL 590s and while testing the Revel C208 I was about to declare it my favorite center except that when actually testing with the 590s in some scenes something odd happens with imaging.
For instance, during the white council scene in Hobbit part 1 when Gandalf is talking to Saruman, in several occasions there is a "ghost" voice between center and right speaker.
With the Monolith thx 365c and Infinity RC263 this voice is pretty solid anchored and sounding.
With the c208 the voice almost has an out of phase quality to it. I mean it may sound like a larger soundstage in a way but just doesnt seem quite right to me like a little too diffused.
I tried different stand sizes, positioning, tilting etc. Can't seem to shake that sounds from my brain.
I am going to retry tomorrow as my brain is burned out from all the testing.
Any ideas what could be happening.
This was with and without Audyssey corrections btw.

 

[Chrispy]

Speakers are one thing, how you set them up another, and don't see much on that. If I think about it I might put those discs in and see if I can see what you're referring to. More info/measurements/etc would be more helpful than your imaging impressions perhaps, too.

 

[GabrielPhoto]

Speakers are one thing, how you set them up another, and don't see much on that. If I think about it I might put those discs in and see if I can see what you're referring to. More info/measurements/etc would be more helpful than your imaging impressions perhaps, too.

Does this help?

 

[Chrispy]

Does this help?

The manual? No....how about a pic of your speaker setup?

 

[GabrielPhoto]

The manual? No....how about a pic of your speaker setup?

Manual? That is the measurement from REW so you can import it and check all the tabs. I thought you wanted to see measurements.

 

[Chrispy]

Hmm I got a manual, could be download didn't go well or renaming unzipped file?

yep, error on my end but not much there otoh. How about pics of your setup/room....and maybe more info about the measurement so it has some reference.

 

[alex-z]

Your frequency response looks pretty good, although I do see a 2-3dB more energy above 5000Hz than I would normally prefer.

How is your centre channel positioned? That group delay spike at 1000Hz is pretty substantial, in combination with the messy impulse response makes me think there might be a lot of reflective surfaces near the speaker.

 

[YSDR]

Because the JBL 590 and Revel C208 are very different constructions, there can be some phase issues between them if they produce sound at the same time.
Maybe that's what you experiencing.

 

[ernestcarl]

Yeah, some ugly spectrally isolated room reflections around 1kHz:


*some relatively strong Mid-HF early reflections that look rather uneven as well.

Dunno if this is the direct cause of the the weird "ghost" vocal imaging... but it may be contributing to the issue at hand.

 

[GabrielPhoto]

Because the JBL 590 and Revel C208 are very different constructions, there can be some phase issues between them if they produce sound at the same time.
Maybe that's what you experiencing.

I find odd that of 10 other centers I have tested, this is the first one where I experienced this though

 

[GabrielPhoto]

Your frequency response looks pretty good, although I do see a 2-3dB more energy above 5000Hz than I would normally prefer.

How is your centre channel positioned? That group delay spike at 1000Hz is pretty substantial, in combination with the messy impulse response makes me think there might be a lot of reflective surfaces near the speaker.

Yeah, some ugly spectrally isolated room reflections around 1kHz:

View attachment 204166 View attachment 204167
*some relatively strong Mid-HF early reflections that look rather uneven as well.

Dunno if this is the direct cause of the the weird "ghost" vocal imaging... but it may be contributing to the issue at hand.

I need to learn how to interpret those for sure.
Now I wonder is it is a reflection from the big 590s?

In this picture I moved the C208 forward and noticed that the sound was more normal in terms of where the voices where coming from and not having that almost out of phase quality.
When I did the measurements the speaker was almost flush to the screen as I wanted to anchor the sound to the images. Behind the screen there is like a 6" gap before the naked wall (well all fully insulated and concrete after that).
So could it be that the very wide horizontal dispersion of the C208 is creating those reflections from the big 590s flanking it?
I think it has the widest dispersion vs the RC263 and 365c which could explain why the other 2 are not affected?
Changing the height of the stand to a taller one did not help either. Only when I started pulling the C208 forward to get more flush with the 590s drivers is when I noticed the changes.

 

[YSDR]

I find odd that of 10 other centers I have tested, this is the first one where I experienced this though

The 10 other was 2-way or 3-way like the C208?

 

[GabrielPhoto]

The 10 other was 2-way or 3-way like the C208?

Several 3-ways
Paradigm 600c
THX 365c
RC263
Elac UC52
RSC200
Emotiva C2+

Others were
Klipsch RC-7, RC64 III, 504c

2-way
520c

 

[AnalogSteph]

Speaking of phase, make sure all speakers are agreeing on polarity (direction of cone movement in AA / 9 V battery test). AVR setup routines do not always catch this, and it may vary even within one manufacturer.

 

[ernestcarl]

So could it be that the very wide horizontal dispersion of the C208 is creating those reflections from the big 590s flanking it?
I think it has the widest dispersion vs the RC263 and 365c which could explain why the other 2 are not affected?

Quite possible. You could just cover those with (or hold up) an absorptive blanket while doing your measurements in order to find out or pin-point where it's mostly coming from.

I need to learn how to interpret those for sure.

You could just compare what you have with a "theoretically perfect" IR.



The reflection-decay characteristic of the "untreated room" in the example above is much better than what we saw previously with your center channel. Although there is still relatively a lot of early and late arriving energy in the 1kHz (1/3) filtered IR (green plot), there are no strong reflections interfering with the main initial peak.

 

[mikhailf]

Several 3-ways
Paradigm 600c
THX 365c
RC263
Elac UC52
RSC200
Emotiva C2+

Others were
Klipsch RC-7, RC64 III, 504c

2-way
520c

I am interested to hear which out of 2 you liked more:
1. RC263
2. THX 365C

Both are within my budget for the center with Studio 580 and I am trying to decide between RC263, THX-365C and SVS Ultra. I forgot to add an old stock of Revel C12.

 

[GabrielPhoto]

I am interested to hear which out of 2 you liked more:
1. RC263
2. THX 365C

Both are within my budget for the center with Studio 580 and I am trying to decide between RC263, THX-365C and SVS Ultra. I forgot to add an old stock of Revel C12.

I will pick the RC263 in terms of better matching the Series 5. It has less "projection" than the Monolith so it does not create as good a ventriloquist effect as the Monolith but in other ways, it sounds better and surely more beefy sound as it has deeper extension.
Monolith would be my preference if I want a wider soundstage that anchors better to the screen but of course, how this effect works for each of us varies.
Hard to go wrong with either.
The Ultra will not be my choice between those 3.

 

[mikhailf]

I will pick the RC263 in terms of better matching the Series 5. It has less "projection" than the Monolith so it does not create as good a ventriloquist effect as the Monolith but in other ways, it sounds better and surely more beefy sound as it has deeper extension.
Monolith would be my preference if I want a wider soundstage that anchors better to the screen but of course, how this effect works for each of us varies.
Hard to go wrong with either.
The Ultra will not be my choice between those 3.

thank you - this helps.

any idea on old revel model c12?

 

[GabrielPhoto]

thank you - this helps.

any idea on old revel model c12?

Sorry never heard that one :/

 

[mikhailf]

Sorry never heard that one :/

thank you