Old KEF's need center

[dbissett]

I have a great pair of KEF RDM Two's and a Q100 center I bought at the same time about 15 years ago. The RDM's are fine but the Q100 is pretty muddy so I'm thinking of just replacing that rather than all three. But I don't have any idea how well KEF's current center channel speakers would match the RDM's. Anyone have any ideas about this? Thanks.

 

[TLS Guy]

I have a great pair of KEF RDM Two's and a Q100 center I bought at the same time about 15 years ago. The RDM's are fine but the Q100 is pretty muddy so I'm thinking of just replacing that rather than all three. But I don't have any idea how well KEF's current center channel speakers would match the RDM's. Anyone have any ideas about this? Thanks.

I think you have either a speaker out of phase or a speaker position issue. The Q 100 is not a muddy speaker, if anything a little on the aggressive side. May be a photograph or two of your system would help us advice you.

 

[dbissett]

Perhaps muddy isn't the right word....the specific problem is that dialog is often difficult to understand and we often raise the volume to compensate, which really doesn't solve the problem. Should have added I'm using a Marantz NR1501, which others have suggested may need upgrading and that's in the plan too. The RDM's are tucked into a bookshelf with space around them about 7' high and 8' wide, while the Q100 is directly above the screen 5' high with plenty of space around and behind it (the screen actually sits at the front edge of lower cabinets). I'll look at the phase issue.

Dave

 

[TLS Guy]

Perhaps muddy isn't the right word....the specific problem is that dialog is often difficult to understand and we often raise the volume to compensate, which really doesn't solve the problem. Should have added I'm using a Marantz NR1501, which others have suggested may need upgrading and that's in the plan too. The RDM's are tucked into a bookshelf with space around them about 7' high and 8' wide, while the Q100 is directly above the screen 5' high with plenty of space around and behind it (the screen actually sits at the front edge of lower cabinets). I'll look at the phase issue.

Dave

View attachment 21841

I'm sure muddy is the right word.

You DO NOT have a speaker problem, but a speaker position problem.

Let's get to the point. That installation is the poster boy for how to get muffled sound.

You can not put the RDM's on their side for a start. That creates a huge lobing error.

Next you have speakers in cavities. You are certainly going to have cavity resonances and all sorts of complex unwanted reflections form those open cavities.

There is just no way you will get any vocal clarity from that installation.

Speakers can not be set in cavities like that. They need to be about 14" from boundaries.

Your best bet is to fill the center cavity with polyfill and put in a baffle, and have the center protrude a little.

The mains need taking off the shelves, and putting on stands, 14" from a boundary with the tweeter height at 36".

A bookshelf speaker is a misnomer. A bookshelf is one of the worst places to put them.

Yours are on their side, far too high and in a cavity. You pretty much did everything wrong you could have!

 

[dbissett]

Yes, well, unfortunately the room was not designed well for sound at all so a lot of compromises are present. (The view is looking across a 19x21' room, and the ends of the room are either solid windows or open, otherwise I would reposition the whole system.) But you gave me some things to work on. Taking your feedback and the KEF manual together, the biggest solvable problems are the height of the speakers and the fact that there is zero room behind them. Given the architecture I can't put them on stands but I could move them to the counter just above the lower cabs. That would put them at roughly the right height and also allow adequate space behind the speakers, according to the manual. Would you expect the difference in height between the RDM's and the center to be a problem?

 

[TLS Guy]

The mains are just far to high and on their side.

So you are getting an enormous ceiling reflection. The fact the speakers are on their side, means the distribution is vertical up and down and needs to horizontal. That is one of your issues with the mains. The way you have it will never give you clarity. Getting the speakers lower and vertical will help a lot, and filling the cavity in which the center resides.

 

[Pogre]

Yes, well, unfortunately the room was not designed well for sound at all so a lot of compromises are present. (The view is looking across a 19x21' room, and the ends of the room are either solid windows or open, otherwise I would reposition the whole system.) But you gave me some things to work on. Taking your feedback and the KEF manual together, the biggest solvable problems are the height of the speakers and the fact that there is zero room behind them. Given the architecture I can't put them on stands but I could move them to the counter just above the lower cabs. That would put them at roughly the right height and also allow adequate space behind the speakers, according to the manual. Would you expect the difference in height between the RDM's and the center to be a problem?

Not as long as they're roughly the same height. My center channel is about 4 or 5 inches higher than my main speakers and I have no issues. The goal is to have the tweeters at roughly ear height (36-38") and pointed at you from your listening position.

I think if you get your speakers in the correct orientation and a couple stands (or even find something you might have around the house the right height to set them on and experiment), you'll be blown away by how much better it sounds. It might even convince you to get a little creative and find a way.

 

[tyhjaarpa]

If you cannot get your center speaker on ear level you can use these pads https://www.amazon.com/gp/aw/d/B00SVRLQSE/ to angle your center so it is pointing on ear level on your seats. I personally have center under TV and I have used pads like these so it is on perfect angle and it sounds great.

And like have been said your bookself speakers should not be on their side and tweeter should be on ear level when you are seated. And they should have enough space to breath as well. When you get these things right it should sound a lot better.

 

[WaynePflughaupt]

Does your receiver have independent EQ for the center channel? If so a cut in the 200-400 range may reduce any boominess and make dialog more intelligible.

Regards,
Wayne A. Pflughaupt

 

[dbissett]

Repositioning the mains helped enormously. I brought them down to the lower cab counter top in the photo, set to the front edge of the counter. Big difference. Thanks for all the feedback.

 

[dbissett]

Although it's better, there's still quite a bit of distortion going on because the mains are at the front of a large cavity, as you can see in this photo...

The counter top they're sitting on is 48" wide x 16" tall x 10" deep (measured from the back of the speaker). Could I kill the effect this cavity is having by installing sound deadening material on the back wall of the cavity at a minimum, and even the sides too if necessary?

 

[TLS Guy]

Although it's better, there's still quite a bit of distortion going on because the mains are at the front of a large cavity, as you can see in this photo...View attachment 21861

The counter top they're sitting on is 48" wide x 16" tall x 10" deep (measured from the back of the speaker). Could I kill the effect this cavity is having by installing sound deadening material on the back wall of the cavity at a minimum, and even the sides too if necessary?

I think that would help. However the cavities really need filling.

 

[dbissett]

Filled with what? Not sure what you mean.