phase 180degree switch

[basshead]

i paid a visit to my local richer sounds recently, i asked the sales-man what the '180 degree phase switch' does on subs. he said:

''when the room dimentions are in multiples of 4 then the sound wave bounces back and the echo cancels out the sound coming from the sub its self''

knowing nothing of how sound waves work i didnt ask any further questions, can someone tell me what on earth he was talking about please?

 

[Messiah]

Right, and I'm not 100% on this but I think the phase switch alters when you sub driver moves in and out. This way you can match the speakers and the sub so that they are all 'pushing' or 'pulling' at the same time.

Does that make sense??

(personally I have found it difficult to notice a difference but there you go....)

 

[chebby]

If they are all pushing and pulling in the same time then I am confused.

The bass drivers in the stereo-pair (actually all the drivers) will be in synch with each other if the polarity is correct.

But a sub has lower frequencies so can it ever be in synch with the stereo-pair's drivers which are producing more cycles per second?

I guess if you place the sub near one of the stereo pair and experiment with switching phase then one setting will sound louder if you are correct.

The loudest should be correct (I think) because of positive reinforcement.

A bit like if you face two identical speakers in front of each other with a small gap between them and have one speaker connected out of phase. The bass notes - especially - cancel each other out and they will sound quiet. Old speaker 'running-in' trick. When in the same phase they are much louder.

Just a thought.

Something still wrong there to me.

 

[Messiah]

I have found THIS

Now who can disagree with Mr E!

 

[basshead]

thanks, that link explains it well.

i still have no idea what the richer sounds sales-man was on about with his 'multiples of 4' stuff though! i'll just remember not to ask the same guy for advice again!

 

[Messiah]

Maybe you should tell him to research his products!

 

[matengawhat]

i think he prob meant that its to do with the placement - if the sub is half the distance away from you that the speakers are you will prob use it

 

[Mike_Schmidt]

What does phase180 do to 2 channel music then, my Parasound pre has it?

 

[Andrew Everard]

Some discs sound better with phase reversed, and some components can invert absolute phase. The switch on your preamp lets you invert phase to compensate, but it will do so for the whole system, being on the preamp.

It's a case of 'suck it and see': use the setting that gives the sound you like most.

 

[Anonymous]

I wounder if the richer sounds saleslad used to work for halfords?

6 years ago when looking at car audio i was told bass quality did not matter and just buy cheapest sub and amp for my car! Hence i just bought my stuff off the internet to fit myself.

At the time i had already wired my car supply ready for the 2 amps. He also said because i had wired 2 separate supplies for the amps i had introduced more resistance and should of ran 1 and just teed off for the 2 amp. Also he said i should have earthed to the chassis were i had ran the earths back to the battery. I tried to expain star earthing and that the car chassis would have noise off the car electronics,and using a bit of ohms law tried to explain it was actually less resistance!

Yes i walked out flustrated but my dad thought the whole experience funny...