2. tech-talk
  3. 1067441853

Inactive speakers in the room...any effect?

A recent thread degenerated into a discussion about whether an inactive speaker in the listening room affects the sound of active speakers. I should have been more tactful, and called it a "hypothesis" instead of a "myth".

Now, a hypothesis can be proven by analytic means or by experiment. This particular hypothesis, from the analytic approach, is very unlikely to be true. So, we go on to an experiment.

A listening test was described where a group of listeners were unanimous in saying that sound quality was degraded by an inactive speaker. (By the way, I don't understand why, if there were any effect, it would have to be a degradation rather than an improvement).

However, to be acceptable as a proof, the experiment would need to be done as follows:
1. The inactive speaker should be introduced and removed from the room in such a way that the subjects, and the person conducting the experiment, cannot tell if it is in or out.
2. The listening test should be performed a number of times. A dozen might be sufficient. More would be better, but the subjects would get bored and results would be degraded.
3. The subjects should record their observations (Speaker IN/Speaker OUT) in such a manner that they do not know how the others are voting.
4. The results must be tabulated and analyzed in a statistically valid way.

I doubt that the reported experiment was done this way. It apparently convinced the subjects, but does not constitute a proof acceptable to an objective non-participant like me. Lacking a valid experiment, I must rely on the analytic approach, and find the hypothesis untrue.

Another game that would be fun would be to conduct the experiment in the manner that I suspect it was done, where everyone knew when the speaker was in or out, but use a speaker that, unknown to the subjects, has had its cones immobilized with glue and the vent (if any) closed off.
I think I know how that would come out if the subjects were believers. (Or, for that matter, if they were nonbelievers). This exercise would indicate how much confidence should be put in the experiment that was done.

Are we having fun yet?
eldartford
clueless
763 posts
 
Our audio club has had a similar problem but with inactive beer cans. Before we get half through a meeting the empty bottles are acting like little Heimholtz resonators and the cans are just playing their own one note tune.

After copious study we decided to go to the foam cooley cups which have a great damping effect. If things sound a unnaturally bright in your system I suggest you clear the room of inactive aluminum cans or go to an audio-grade cooley cup.

Sincerely
I remain
unsound
7,329 posts
 
Clueless, I can see it now, specially formulated from a rare an exotic rubber tree, cryongenicly treated and mounted on a sandwich of sorborthane, exotic wood, rare stone and kevlar over tip toes, with a remote controlled blue light that can be programmed to glow ones name at the touch of a remote control, cooley cup. Don't forget the sipfrom coasters!
rel
225 posts
 
Unsound: Amazing! I have just such a cup!!
Since it's just a prototype (sorry--can't name the manufacturer as I signed a nondisclosure agreement) I didn't think anyone knew about these yet. As for the sonic effects, I can't say for sure: they require at least 10,000 hours of break-in.
rives
953 posts
 
Eldartford asks: "If this is so, why don't the room treatment merchants design a box with a passive radiator?" Well they have. It's called Modex made by RPG. Different volumes and front material determine the frequency. With the speaker design, it is hit or miss in terms of the resonance frequency. It can work to the benefit, if it is resonant at the modal response of the room. It can also work to the deteriment if it's not. It's really hit or miss--not very scientific. As to TWL's phone experiment--seems highly unlikely that a phone would resonate enough energy to make a difference. However, the RF produced by cordless phones is a signficant problem, and I'm not surprised that it being in the room would create a detrimental effect--it's reason though I don't suspect to be the diaphramatic nature of the speaker.
slappy
903 posts
 
ok, all of this is nice and well, but everyone seems to be skimming on the real question..

How long does it take for a set of inactive speakers placed in the room as treatments to break in?

hahahahahahahaha

Hey, does anyone think a modified Perch from Marco could be used as an accoustical lens?

Twl, i totally respect what you say and believe you definatly know what you are talking about. Your contributions to these forums are very well appreciated and your opinions and suggestions are held in high regard, But come on. A telephone speaker? Are you sure yer not pullin our collective leg?

I gotta say, i know alot about audio gear and how it works, but my actual first hand experience on these high end dedicated listening rooms is somewhat limited. But some of the things that people will say really blows my mind.
I guess it is one of those things i will believe when i experience it. Other than that, man that sounds pretty far fetched.

I saw a picture of a guy's listening room, he had all the accoustical treatments. Including what appeared to be a 3x6 foot legnth of foam rubber which looked to be glued to the top front of his speaker and leaning forwared and stapled to the ceiling.
Man that looked rediculous. To each his own though.

I still have a nagging suspicion that alot of these tweaks and stuff are the "Kings new Clothes", I definatly understand the importance and fundementals of accoustics, but man. Some of this just seems kinda... crazy?

I remember this time i was listening to nick caves "O'Malleys Bar" and my dog walked into the room and farted. Man, the soundstage collapsed, the imaging died...
More to discover