[coachtrip_fan99]

I have a panasonic mini hifi... its been disconnected for about a month while we decorate.

Tried to use it yesterday, and all is fine when listening to the radio (eg, Radio 1) but when I want to listen to local radio stations, I put it on mono mode - due to poor signal.

Problem is = when I press mono (or if it automatically goes to mono) the volume drops CONSIDERABLY... so that it need to be turned up to full, before anything can be heard.

All other sources are fine.

Whats going on here?

[chrisjr]

One possibility is something is out of phase. If you got the +ve and -ve connections on one speaker reversed then that will put them out of phase. Though usually if they are spaced apart it just leads to poor stereo imaging and an odd sound in mono. If the speakers were side by side then there could be some cancellation of the sound. But getting cancellation in mono due to a phase error would be more likely in the tuner stage or some other part of the circuitry rather than the speaker connections

Or there is a fault with the speaker connections which means the two speakers are wired in series across the two +ve terminals (ie the -ve isn't connected to the common earth of the system) Though if that were the case it would sound very odd in stereo mode as well. You would effectively be listening to "Left minus Right" so anything that was equal in level on both channels cancels out, as would be the case with mono.

It would be worth checking the speaker connections and make sure everything is correctly connected up just in case. That would be the easiest thing to correct, anything else may cost more to fix than the system is worth.

[coachtrip_fan99]

thanks. I will be sure to check this.

The system was quite inexpensive to be honest, SO i may just end up replacing it..... although it's getting harder to find normal hifi's now, everyone just seems to sell bloody ipod docking units.

[evil c]

What sort of aerial are you using and I know this sounds stupid, but if it is not a roof aerial have you tried moving it to get the best reception? Have you got anything interfering with the aerial like household objects in front of it?

There's plenty of cheap hifis around...Amazon or even secondhand from Cash Converters or similar or in your local paper or auction house or just get a new radio if you can connect it to yours.

[coachtrip_fan99]

thanks so much but ive solved the problem now.

chrisjr. you had hit the nail on the head....... in my haste.. I had wired up the speakers, one into both +ives and one in both -ives.

Feel like I right idiot now!!!

[chrisjr]

Quote:

Originally Posted by coachtrip_fan99

thanks so much but ive solved the problem now.

chrisjr. you had hit the nail on the head....... in my haste.. I had wired up the speakers, one into both +ives and one in both -ives.

Feel like I right idiot now!!!

Didn't you wonder why one speaker was a bit quiet?

We've all been there, even those of us who get paid to do this sort of stuff and should know better

[coachtrip_fan99]

Quote:

Originally Posted by chrisjr

Didn't you wonder why one speaker was a bit quiet?

We've all been there, even those of us who get paid to do this sort of stuff and should know better

no... both speakers were quiet.... but only when fm mono mode.

any other input and the speakers worked fine.

Thats why I assumed they were wired in correctly until I read your message!

thanks, anyway.

[The Wizard]

Frequencies/sound waves cancelling one another out. Are you sure you've got the + and - the right way around?

Edit: Sorry, just seen the above reply. Basically what I said.

[chrisjr]

Quote:

Originally Posted by coachtrip_fan99

no... both speakers were quiet.... but only when fm mono mode.

any other input and the speakers worked fine.

Thats why I assumed they were wired in correctly until I read your message!

thanks, anyway.

The speaker wired into the two -ve terminals would have been totally silent if those terminals are wired to common earth as is normally the case. The only way they could make any noise is if the speaker amps drive both +ve and -ve terminals.

That is done on a lot of car radios but is not very common on household stereo kit.

[coachtrip_fan99]

oh right.

Bit of a mystery then. Am just glad its all working again now, and I dont have to buy a new stereo.

Thanks.

[mooghead]

It can be very interesting listening to some stereo music when the speakers are phased though. This is the technique some systems with a 'karaoke' feature use.

[coachtrip_fan99]

Quote:

Originally Posted by mooghead

It can be very interesting listening to some stereo music when the speakers are phased though. This is the technique some systems with a 'karaoke' feature use.

is that to sort of remove the vocals?

[coachtrip_fan99]

Oh and another question... If anybody can help me.

In my kitchen I have a Panasonic Flat Panel system, model no. DCM292

When listening on FM, there seems to be no way to force it to use mono mode.
It keeps drifting out of stereo and mono...... but I just want it to stay on mono as its much clearer.

anyone know how to do it on this specific model?

[mooghead]

Quote:

Originally Posted by coachtrip_fan99

is that to sort of remove the vocals?

Yeah, what it does is remove every sound that is equally shared by both speakers (usually vocals and bass) and only plays the 'stereo' sounds out of the speakers. Wire the speakers up wrong again and play a cd to see what I mean.