Using a stereo 3.5 mm audio jack connected to a mono speaker: Out Of Phase Stereo (OOPS)

[Saidera]

I just couldn't find any info anywhere on using Apple USB-C Headphone Adapters with a 3.5 mm audio jack connected to a speaker. I know this is due to the sheer simplicity of it.

But I have questions!

1. Mine are mono only (3.5 mm to two wires, red and white), but when you input 3.5 mm stereo to a mono speaker, certain popular music have the vocals etc cancelled out (like the karaoke function in some editors) so the background music comes out very clear. I have a direct 3.5 mm to 2 ch speaker system which used to be connected to the Logitech subwoofer. That stereo speaker system works fine. Stereo to a mono is not straightforward. The bass speaker from Logitech is like a low pass filter. Other sources distort badly. There is a lack of clarity in the sound in some complex tracks. Or nothing is heard at all. Why does this happen? Or is this simply the speaker's frequency response?

2. My 4 ohm sony speaker distorts when used with apple dongle on higher volume. But the 8 ohm tv speaker works very well. Would a dongle with 2VRMS avoid this distortion?

I was always amazed to see how nearly nothing can be heard on speakers from a Realtek chip via 3.5 mm, but Apple dongle can drive it plenty loud.

 

[Zek]

Are you talking about passive or active speakers?
No one USB dongle is designed to drive passive speakers, but headphones or active speakers.

 

[Saidera]

These speakers are all passive and taken out of their enclosures. I agree that this is not the usual way of using USB dongles.

 

[KeithPhantom]

These speakers are all passive and taken out of their enclosures. I agree that this is not the usual way of using USB dongles.

If you are using these dongles as amps for passive speakers, they may be running out of juice. At least I would use small integrated amplifiers or small amplifies for speakers.

 

[Saidera]

Thanks for the replies!

No, Apple USB-C is sufficiently powerful.

It's just DIY bare speakers from cars, TVs, 5.1 ch systems...connected to a stereo 3.5 mm cable and powered by stereo signal>mono speaker

 

[Saidera]

I found the answer by myself anyway - for the record, if anyone else wonders why the mono speaker goes quiet, it's because of this:

https://en.wikipedia.org/wiki/Out_of_Phase_Stereo
https://www.waves.com/tips-for-mono-compatibility-in-a-stereo-mix

I reckon I might've inverted the polarity...but I like it. I can 'eliminate vocals in a stereo track (as vocals tend to be panned centre) to create crude karaoke tracks'.

 

[Saidera]

Don't forget this too for testing speakers in mono: https://www.audiosciencereview.com/forum/index.php?threads/speaker-testing-why-mono-is-better.21681/

 

[Bamboszek]

If I understand correctly you are shorting both channels and driving 4 ohm load with USB dongle.
Even if dongles IC include some kind of protection, that's definitely running out of specification and dongle would be probably damaged sooner or later.
If you want experiment like this at least connect two 8Ω drivers in series to get more reasonable 16Ω load. And don't short stereo channels to mono.

 

[Saidera]

If I understand correctly you are shorting both channels and driving 4 ohm load with USB dongle.
Even if dongles IC include some kind of protection, that's definitely running out of specification and dongle would be probably damaged sooner or later.
If you want experiment like this at least connect two 8Ω drivers in series to get more reasonable 16Ω load. And don't short stereo channels to mono.

So there is a short? How does the OOPS effect relate to that? If my jack was mono, I guess it would not have the OOPS. It is a problem arising due to only two wires and a ground wire attached to the jack. If it had four wires, I'd have stereo. Apple provides a warranty, and I don't think connecting a mono speaker to the dongle is misuse or abuse of the dongle. I'll report here if it gets damaged...