Hi Everyone,
I am building a switch box to set my audio input levels from stereo to mono.
I know that for the best result a true mono mix of the audio should be made, but then still one of the stereo recording inputs should be phase inverted, something this switch also should do.
Can I get some feedback/check on this circuit?
Please note that I am only familliar with electronics to a very small degree, and only understand some basic principles.
Stereo to Mono switch with phase inverter Circuit.
You do not have the required permissions to view the files attached to this post.
Re: Stereo to Mono switch with phase inverter Circuit.
Hi Dane,
Looking over your Circuit, if I'm reading it correctly, it looks like in Switch Position 1 the Stereo Signal passes through unaltered. In Switch Position 2, the Signal is Summed to Mono in a similar way to the Circuits within this PDF, but with the addition, that Left Output is in Anti-phase or Opposite Polarity to the Right Output. Just out of curiosity, might I ask what is the reasoning for this Polarity change?
Regards Soulbear
Looking over your Circuit, if I'm reading it correctly, it looks like in Switch Position 1 the Stereo Signal passes through unaltered. In Switch Position 2, the Signal is Summed to Mono in a similar way to the Circuits within this PDF, but with the addition, that Left Output is in Anti-phase or Opposite Polarity to the Right Output. Just out of curiosity, might I ask what is the reasoning for this Polarity change?
Regards Soulbear
You do not have the required permissions to view the files attached to this post.
- Stevie342000
- Posts: 497
- Joined: Mon Dec 21, 2009 2:12 pm
Re: Stereo to Mono switch with phase inverter Circuit.
There may be a further issue that needs research not sure it applies to all signals or just to tape but if you are summing tracks to mono you end up with a 2-3dB lift at around 700Hz and this may be where the phase error comes in and thus why the anti-phase is useful. This may have only applied to 3-track tape as stereo was intended to be L-C-R. It was usual to record left & right as normal from microphones and a single microphone was used for the centre track. Thus you got a 3 channel stereo mix, mono mix and a stereo mix. It was usual to blend a bit of the centre track in to the final mix to fill out the whole in the middle. Take a look at Mercury Living Presence recordings, RCA Living Stereo, Decca UK etc, mostly all 3 track recordings from 1954 onwards, they knew stereo was coming so the major labels had a backlog of stereo tapes in the archive ready for when stereo entered the mass market.Soulbear wrote:Hi Dane,
Looking over your Circuit, if I'm reading it correctly, it looks like in Switch Position 1 the Stereo Signal passes through unaltered. In Switch Position 2, the Signal is Summed to Mono in a similar way to the Circuits within this PDF, but with the addition, that Left Output is in Anti-phase or Opposite Polarity to the Right Output. Just out of curiosity, might I ask what is the reasoning for this Polarity change?
Regards Soulbear