Stereo to mono
Posted: Tue Sep 08, 2020 9:43 am
I have been thinking of this recently ever since I heard my sister's single speaker B&O system. It worked really well. Obviously you don't get stereo effects like different instruments from different speakers or say a full kit drum roll panned from one speaker to the other. Thing is I didn't miss it at all
The left and right channels are summed and just come out of the same speaker. I have had the thought that listening mono through one speaker would get better results when using omni directional type speakers. Semi omni would be better than point a squirt if you weren't in the sweet spot but not as good as a true omni or quasi omni.
My diy speakers have tweeters mounted firing forward, upwards, downwards, backwards and to each side (six in all). Whilst not a true omni it is closer than a semi omni. With the bass and mid bass upward firing then that takes care of itself - it is just the tweeters to worry about with their directivity and power off axis.
The good thing about mono with omni or quasi omni is that the left and right channel information is coming from the same driver(s) so you can't be further away from one than the other. You can still be further away from the mid bass than the tweeter but that is a topic for another thread.
So what is the best way to combine the left and right signals from our stereo sources ? I don't know yet
I need to do some more research or ask somebody who knows - anybody here know ?
You can't just join the two channels together and hope for the best. The signals will fight each other and the magic smoke will surely appear
Get an amp with a mono switch ? Nope don't want to do that. The only two ways I currently know of how to do it is to combine the two channels before or after the power amplifiers.The following is all my limited knowledge on the subject so far and could be wrong.
Combining the signals after the power amp involves bridging the two amplifier modules. Doc did not endorse this in anyway as it resulted in repairs
Essentially the bridged amplifier see's the speaker load as half of what it originally was. So an eight ohm load becomes a four ohm load. If the speaker's impedance dips down at a certain frequency then you could be in trouble. Same if you tried to bridge the amps and the speaker is rated at four ohms nominal impedance. The amp would see a two ohm load and if it was NVA (along with many others) would probably overheat and destroy the output transistors and god knows what else.
The other way that i know of and done before the power amplifier is to join the two channels to a common point but with series resistors in each line just before the join. The 0V of each is just joined together. I don't know the pros and cons of this method. I have seen 1K resistors mentioned as a good resistance to start with so that the two channels are adequately isolated from each other but who knows. There must be signal loss with a resistor in line, possible sq degradation and possibly other issues concerning impedance.
Anybody got views or experience on this ?
![Shocked :shock:](./images/smilies/icon/eek.gif)
The left and right channels are summed and just come out of the same speaker. I have had the thought that listening mono through one speaker would get better results when using omni directional type speakers. Semi omni would be better than point a squirt if you weren't in the sweet spot but not as good as a true omni or quasi omni.
My diy speakers have tweeters mounted firing forward, upwards, downwards, backwards and to each side (six in all). Whilst not a true omni it is closer than a semi omni. With the bass and mid bass upward firing then that takes care of itself - it is just the tweeters to worry about with their directivity and power off axis.
The good thing about mono with omni or quasi omni is that the left and right channel information is coming from the same driver(s) so you can't be further away from one than the other. You can still be further away from the mid bass than the tweeter but that is a topic for another thread.
So what is the best way to combine the left and right signals from our stereo sources ? I don't know yet
![Think :think:](./images/smilies/eusa/think.gif)
You can't just join the two channels together and hope for the best. The signals will fight each other and the magic smoke will surely appear
![Rolling Eyes :roll:](./images/smilies/icon/rolleyes.gif)
![Liar :liar:](./images/smilies/eusa/liar.gif)
![Liar :liar:](./images/smilies/eusa/liar.gif)
![Liar :liar:](./images/smilies/eusa/liar.gif)
Combining the signals after the power amp involves bridging the two amplifier modules. Doc did not endorse this in anyway as it resulted in repairs
![Rolling Eyes :roll:](./images/smilies/icon/rolleyes.gif)
The other way that i know of and done before the power amplifier is to join the two channels to a common point but with series resistors in each line just before the join. The 0V of each is just joined together. I don't know the pros and cons of this method. I have seen 1K resistors mentioned as a good resistance to start with so that the two channels are adequately isolated from each other but who knows. There must be signal loss with a resistor in line, possible sq degradation and possibly other issues concerning impedance.
Anybody got views or experience on this ?