2. speakers
  3. 1376417568

KEF Q800ds heads up check yours

As happy as I have been with my KEF Q series HT system, I've struggled with getting the imaging the same L/R. I stumbled across an article that said to check the Q800ds for phase / matched pair using a battery... and in so doing discovered that I did not have a matched pair, but rather two the same... the result being that no matter how they were set up one side would be in phase and the other out of phase when used as side surrounds and if used as rear surrounds the center null point could never be correct... unless you flipped one upside down. If you are using Q800s you should check yours!

Although I have had good information in the past from my dealer; accessories4less, they have been uncooperative on this issue... notified them a month ago. So, I proceeded to rewire my 1 year old +$500 pair of speaker myself....which sucked! and took longer than it should have... getting the wires free of the silicone glue was tough... but in reality I should never have had to do this...

The results though were well worth the effort and now the sound is correct and even L/R in the room... imaging is just great and the true dipole effect is now in play.

Also, FYI when I pulled the Q800s down off their stands to do the phase check I found that a 3" corner piece of the black laminate pealing from a bottom corner on one of the speakers... again nothing from the dealer except to reglue it myself. LOL You should check yours....

Noteworthy is that in my large room (18' x 20' with a +14' cathedral ceiling) I was never able to get the sound as "full" as I expected using the Q800s for sides and KEF Ventura 5s for rears... once I sorted the Q800s I moved them to the rear and moved an old pair of Dahlquist dq-16s that I had in another system into the side surrond position.... what a wonderful difference... sound is now everything I hoped for when I built the HT system... especially for movies and music! (using Q900s for mains and a Q600 for center channel)... the Q800s just don't have the output / sound field necessary to fill the room the way it needed to be.... but are more than up to the task of rear surrounds.
jimpittsburgh
7 responses Add your response
Ag insider logo xs@2x
drubin
3,274 posts
 
Great story.
stereo5's avatar
stereo5
6,405 posts
 
Instead of going through all that trouble, why didn't you just reverse the speaker wires at the speakers binding posts?
rlwainwright
1,904 posts
 
>> Instead of going through all that trouble, why didn't you just reverse the speaker wires at the speakers binding posts? <<

Indeed - a 5 minute fix...

-RW-
jimpittsburgh OP
34 posts
 
I tried reversing the connections, but it did not change which of the two speakers was the + side. I confirmed this using the battery and trying it connected both ways... I had to change the internal speaker connection or flip one upside down which was not wife acceptable.. (looks stupid were the exact words).
jimpittsburgh OP
34 posts
 
here is the link I was refering too;

http://www.avforums.com/forums/speakers/1583804-kef-q800ds-r800ds-important-question-kef.html
jimpittsburgh OP
34 posts
 
Here are two links to discussions on dipole/ bipole speakers that should help with positioning and getting the + and - aligned correctly. Also, I think buried somewhere in these many pages is a direct reference from KEF and how they are suppose to now be labeling the Q800s L and R and assuring that they are matched pairs... getting them right makes a big difference in the null point/ sound field.

A Guide to Bipolar, Dipolar, & Direct-Radiating Monopole Surround Speakers (PART I) - Blu-ray Forum
http://forum.blu-ray.com/showthread.php?t=66471

A Guide to Bipolar, Dipolar, & Direct-Radiating Monopole Surround Speakers (PART II) - Blu-ray Forum
http://forum.blu-ray.com/showthread.php?t=170720
jimpittsburgh OP
34 posts
 
update to previous info about the faulty KEF Q800ds speakers:

I exchanged both emails and a few phone conversations with a gentlemen named Corey at KEF USA.

He was very gracious and sent the info I provided on to an "engineer" at KEF somewhere. The response (see below)was total BS and ignored the null point/ phase issue.. which was the whole point. They are admitting to nothing which is not surprising is it? Very ticked.... and would suggest that any poor sod like me that ownes a pair of Q800s do the switch or flip one over... and to anyone is considering the purchase of Q800ds speakers DON"T!

hers the response from KEF "At mid/high frequencies, the two drivers are arranged to work out of phase, resulting in complete cancellation from the drivers at the listener position. The idea is that the listener can't locate the source (due to the cancellation) and only hears the reflected sound from the surfaces around the room. This is what gives an impression of a surround sound field.”


Here is a link to the same discussion over on the AV Forum

http://www.avforums.com/forums/speak...e-problem.html

switching the polarity of the speaker wires has no effect on which of the two speakers in each of the Q800ds is the "+" or which one is the "-" in the Q800s... you can try it yourself using the battery test method....

Really ticked off about the whole issue and the less than weak answer from KEF.... The other funny verbal statement made was that the Q800s are only made for use as side surrounds and not to be used as rear surrounds.... a stupid statement at best.... like having a pair of out of phase side surrounds would be OK... And of course this was the issue that started the whole discussion to begin with....uneven sound caused by the Q800s being out of phase with each other!

The simple answer seems to be to just NOT buy KEF Q800ds speakers period! Shame on you KEF
Log in to respond
More to discover
80x80
Borresen - O Series Loudspeakers
80x80
Focal Maestro Utopia Evo
80x80
ATC SCM200PT