Old rules - out the window or ignored?

[CnoEvil]

Back in the day, when you were demoing a pair of speakers, all other speakers needed to be removed from the room.

The reason: If there were other undriven speakers in the room they would - rather like a microphone - pick up the sound of the speakers that were playing, and radiate it back into the room again. This in turn was picked up by the speakers which were playing.
The net effect "ruined" the quality of the sound produced.

So, if you are now using your HT set up for stereo, has anyone found this a problem and has a solution been found that I'm not aware of? - other than having two rooms (not always practical)

 

[Frank Harvey]

I think 'ruined' the sound is a little excessive. Yes, it'll affect what you have, and to get the very best out of a speaker, a dealer will remove any other speakers in the room, or at the very least face the unused pair into each other in order to cancel out any frequencies they tend to add in. If you gently touch the bass driver of a speaker not being used, you'll see what the effect is, although at most frequencies it's fairly minimal - the main issue is when the resonant frequency of the cabinet/driver, which will be much stronger.
Unfortunately, in a 5.1 system, it has to be accepted that the extra unused speakers will be merrily singing along with the main pair.
Don't worry too much

 

[CnoEvil]

I think 'ruined' the sound is a little excessive. Yes, it'll affect what you have, and to get the very best out of a speaker, a dealer will remove any other speakers in the room, or at the very least face the unused pair into each other in order to cancel out any frequencies they tend to add in. If you gently touch the bass driver of a speaker not being used, you'll see what the effect is, although at most frequencies it's fairly minimal - the main issue is when the resonant frequency of the cabinet/driver, which will be much stronger. Unfortunately, in a 5.1 system, it has to be accepted that the extra unused speakers will be merrily singing along with the main pair. Don't worry too much

Cheers David. Not worried, just interested.

Thanks for speedy reply.

 

[the record spot]

Never bothered with it, only ever had one pair going, but even in demo rooms where many speakers were on display and in use, it wasn't an issue.

 

[Anonymous]

Plus, I don't see why speakers in the room would be different from the many other resonating/reflecting objects in a normal room.

 

[CnoEvil]

Plus, I don't see why speakers in the room would be different from the many other resonating/reflecting objects in a normal room.

Good point. Where is a speaker designer or acoustic engineer when you need one?

All I know is, a big issue was made of it 20 years ago. A hifi dealer worth his salt, would never leave any other speakers in the room while you were demoing.

With the advent of HT this advice disappeared - interesting :~

 

[Craig M.]

the boston audio society did a blind test on the founder of Linn to try and prove/disprove his (i believe) theory that another pair of speakers in the room would 'ruin' the sound. he failed.

 

[CnoEvil]

the boston audio society did a blind test on the founder of Linn to try and prove/disprove his (i believe) theory that another pair of speakers in the room would 'ruin' the sound. he failed.

Didn't know that - even more interesting.