Horizontal CC and off axis performance

[Towen7]

I've never owned a horizontally oriented CC speaker but I have read about the issues with of-axis filtering caused by the tweeter being on the same horizontal plane with the mid's. I need to compromise with the Mrs and get a horizontal CC for the living room. I can do whatever I want in the HT.

How far above/below does the tweeter need to be to reduce that affect?
Do horn based tweeters (like the Klipsch RC-64) have the same issues?

 

[Flint]

The bigger problem is having dual midrange drivers placed horizontally. But, there can also be issues with the tweeter being placed horizontally to the midrange in the crossover range. If the crossover is centered at 2kHz, then the issue will be clearly audible from as low as 800Hz to as high as 4,500Hz - depending on the crossover slope and the angle you listening off-axis.

The only way to eliminate the issue is to ensure the drivers are all placed vertically - directly above one another. Or, look for a coaxial solution (KEF, Tannoy, etc). You could also shop for a single-driver fullrange solution (like the JBL Control-1, or *gasp* Bose Cubes).

Personally, this is only a concern if you are not seated close to perfectly on axis. When you sit directly in front of the speaker, the horizontal lobing issue is limited to the room acoustics sound, which is less of an issue.

 

[Haywood]

My sofa is typically about 10 feet in front of my TV and has a seating area about six feet wide. I have a horizontal center channel and have never noticed any issues with the sound while seated on the sofa. I have noticed a change when I sit in my chair or on the love seat, which are much farther off axis. In other words, I don't think a couple feet off axis is that big of a deal. Unless you've got a pretty wide seating area, I wouldn't worry that much.

 

[Nufan]

I thought klipsch "fixed" the lobing issue with the referance series?

 

[yromj]

Klipsch uses what they call "Tapered Array" to help eliminate the lobing issue. Only one of the two drivers is used for the frequency range that would result in lobing between the two identical drivers. There is nothing they can do w/ the frequeny range affected by the mids and the tweeter.

John

 

[Flint]

The tapered array only reduces the impact of the lobing, reducing the frequency where it occurs to about one octave, or so. It doesn't eliminate the problem. Anytime drivers are side by side and operating at high enough frequencies there will be lobing.

 

[malsackj]

Would that lobbing issue be similar to the document I was pointing out on multiple subs and issues. When looking at the graphics on the subs one can see the lobbing?

 

[Flint]

Yes. Any two drivers reproducing the same signal can cause lobing if the drivers are enough apart. The rule of thumb is based on quarter wavelengths. If the frequency being reproduced has a quarter wavelength less than the distance between the drivers, there will be some lobing.