Stupid question of the day

[Ponzio]

Can a center channel output from an AVR be run serially to 2 bookshelf speakers?

 

[markw]

Assuming you respect their combined impedances, your receivers ability to handle that, and you can live with the possible phase shift and imaging issues from having two point sources when there should only be one, I see no reason it cannot be safely accomplished.

 

[ImcLoud]

I Seen a system where they used two centers on top of each other, the tweeter in the bottom one was disabled for some reason but it worked, what would the purpose of this be?

 

[shadyJ]

Assuming you respect their combined impedances, your receivers ability to handle that, and you can live with the possible phase shift and imaging issues from having two point sources when there should only be one, I see no reason it cannot be safely accomplished.

In other words, technically possible to do but will almost certainly sound awful.

 

[markw]

In other words, technically possible to do but will almost certainly sound awful.

Not necessarially awful, but maybe not exactly the magnitude of improvement one would hope for, if not even a little "smeary".

consider impedance swings in speakers. As the frequency varies, it goes high, and then it goes low. In this case, the impedances will go twice as high in a seies configuration, and twice as low in a parallel configuration.

 

[Adam]

In other words, technically possible to do but will almost certainly sound awful.

Why would it sound awful? Not a challenge...just a question. I guess I'm imagining having two bookshelf speakers, laying on their sides and pushed together head-to-head (so that the tweeters are in the center and the woofers on the sides), which would mimic many center channels. Granted, if the bookshelf speakers were far apart, then it kinda defeats the point of the center channel.

I also don't know why people run two centers, but my first 5.1 receiver (a Yamaha from the mid-90s) had speaker outputs for two center channels.

 

[shadyJ]

I can see a lobing mess. Refer to Axiom's highly derided center speakers for examples here. Plus the bookshelf speaker axial response is been turned ninety degrees, and most speakers are built for a good horizontal response, not vertical response.

 

[Swerd]

Can a center channel output from an AVR be run serially to 2 bookshelf speakers?

Technically you can, but, as others above have already commented, there are good reasons why two speakers should not be run per channel. Most likely, one speaker per channel was the intended design.

In addition to those reasons, when two speakers are run serially, the second speaker gets a different signal than the first one. Nearly all speakers have voice coils as part of their electromagnetic motor, and these coils have inherent inductance not unlike the inductor coils in their crossover networks. So, the second speaker will get audio signals that have passed through additional filtering that the first speakers were not exposed to.

To make matters worse, the voice coils move according to the audio signal, changing their inductance as they move. So the second speakers get varying audio signals, depending on the audio content.

Don't hook up speakers in series to one audio channel. It probably won't cause any damage, but it won't sound right.

 

[Ponzio]

well gentlemen ... thank you. I guess that answers that question.

I have a spare pair of Athena AS-B2's and was wonderin'. I will pass on tempting fate.

 

[TLS Guy]

I Seen a system where they used two centers on top of each other, the tweeter in the bottom one was disabled for some reason but it worked, what would the purpose of this be?

Probably the speaker had no or inadequate BSC, and that would be a crude way to correct it, but not recommended.

I use two coaxial speakers in my center. Originally one tweeter was disconnected and one woofer cone fed the BSC signal actively, which it still is. However the SEAS coaxial speakers have a dip centered on 9 kHz and a first order roll off above 12 K. Eventually I decided to feed a correction signal to the second tweeter. This was not easy, but the speaker is now +/- 1db in its operating band. Center speakers are very difficult at least or me, and I suspect others. A center speaker is tough assignment from a design stand point, and I think that is why there are so many bad ones.