This is a genuine question: Is it really a good idea to put two channel stereo speakers into the same small box? If the channel information is actually different then don't the frequencies interfere with each other?
I see a lot of interest online in DYI boomboxes that use chip amps, bluetooth receivers, and two full range drivers in the same small enclosure. Doesn't the little distance between the two drivers nullify most if not all of the advantage of having a stereo image?
I am thinking that using a summing circuit to produce a mono signal for a mono amp would produce a better and more efficient sound, using a single good driver. Would that be practical or advantageous?
The thing that got me started thinking about this is listening to my GF's simple cheap little mobile bluetooth speaker- it is using a stereo signal from her Ipad but of course the sound is similar to those tiny pocket transistor radios from decades ago... I am not sure why she bothers except for the convenience. I'm thinking I might build her a much better little powered speaker with a bluetooth receiver, but should I use two drivers (one for each channel) or sum the channels and just power it in mono? I guess I should add that it would be used in typical smallish house rooms rather than outdoors or larger spaces like people often use boomboxes for...
I see a lot of interest online in DYI boomboxes that use chip amps, bluetooth receivers, and two full range drivers in the same small enclosure. Doesn't the little distance between the two drivers nullify most if not all of the advantage of having a stereo image?
I am thinking that using a summing circuit to produce a mono signal for a mono amp would produce a better and more efficient sound, using a single good driver. Would that be practical or advantageous?
The thing that got me started thinking about this is listening to my GF's simple cheap little mobile bluetooth speaker- it is using a stereo signal from her Ipad but of course the sound is similar to those tiny pocket transistor radios from decades ago... I am not sure why she bothers except for the convenience. I'm thinking I might build her a much better little powered speaker with a bluetooth receiver, but should I use two drivers (one for each channel) or sum the channels and just power it in mono? I guess I should add that it would be used in typical smallish house rooms rather than outdoors or larger spaces like people often use boomboxes for...
I guess you have a point; if the loudspeakers are almost coincident you might as well make it mono. In the old days when boombox still meant radio-cassette recorder they were usually rather wide, so there was at least some horizontal distance between the loudspeakers at the sides, and there was often a primitive stereo crosstalk compensation circuit (spatial stereo) included.
FWIW, I built a wireless speaker using a JBL LSR305 speaker, and adding a rpi and a dac hat. I sum the signals for mono, and it sounds pretty good, way better than the crappy little bluetooth speakers.
The JBL has a built in amp, so you just have to give it a signal. It really wants balanced, but it works fine with a single ended signal if its connected correctly.
It was much simpler to build it mono, and for its purpose, you don't want to lug around two speakers. But I did end up buying another LSR305, so if I want I can connect two of them for stereo, for "serious" listening. There is a switch to change from stereo to mono.
I started making it a bluetooth speaker, but decided to make it an airplay speaker instead, since the family all has apple devices, this works pretty well, at least so far.
I also originally considered making my own speaker, but the lsr305 was less than $100. I could buy the parts, including an amp, and make something that sounded as good for that price, so I just bought the 305 and added a power supply and pi and dac.
Randy
The JBL has a built in amp, so you just have to give it a signal. It really wants balanced, but it works fine with a single ended signal if its connected correctly.
It was much simpler to build it mono, and for its purpose, you don't want to lug around two speakers. But I did end up buying another LSR305, so if I want I can connect two of them for stereo, for "serious" listening. There is a switch to change from stereo to mono.
I started making it a bluetooth speaker, but decided to make it an airplay speaker instead, since the family all has apple devices, this works pretty well, at least so far.
I also originally considered making my own speaker, but the lsr305 was less than $100. I could buy the parts, including an amp, and make something that sounded as good for that price, so I just bought the 305 and added a power supply and pi and dac.
Randy
Two reasons:
1. Who would buy a mono gear when he/she could buy a stereo? Stereo is more advanced than mono, isn't it? 😀
2. The source is stereo, and the summing circuit would cost
1. Who would buy a mono gear when he/she could buy a stereo? Stereo is more advanced than mono, isn't it? 😀
2. The source is stereo, and the summing circuit would cost
I'd suggest going mono.
For the same outlay as two average quality speaker drivers you could buy one high quality driver with the prospect of better sound reproduction.
In addition, the entire enclosure volume can then be dedicated to the single driver and not have to be shared by a pair of drivers.
A simple, resistive summing circuit is cheap and easy to implement.
If using two drivers in a stereo configuration, they should occupy separate compartments within the enclosure to avoid them interacting with each other internally.
For the same outlay as two average quality speaker drivers you could buy one high quality driver with the prospect of better sound reproduction.
In addition, the entire enclosure volume can then be dedicated to the single driver and not have to be shared by a pair of drivers.
A simple, resistive summing circuit is cheap and easy to implement.
If using two drivers in a stereo configuration, they should occupy separate compartments within the enclosure to avoid them interacting with each other internally.
Many sonus setups are effectively mono. The devialet phanton has had rave reviews in mono config. So mono is alive and well and people don't seem too fussed.
stereo from one speaker enclosure can be done , requires some walls for the stereo to work 🙂 Stereophonic Sound from a Single Loudspeaker
With two speakers, there will be some interference (peaks and dips) whether run stereo or mono. Not a big deal since all stereo systems suffer from it 🙂 Value of stereo from a small boom box? Based on my (limited) experience, sometimes you could hear stereo image, but usually you had to be listening near field.
FWIW live sound (I mean Rock concerts and such) IS used as Mono in practice.
In this case, "so everybody in the audience hears the same"
Real Stereo imaging would be available only to 1/3rd or 1/4th of the Audience otherwise, those placed roughly in a centerline, while others would hear, say, "too much/too little guitar" or any other instrument, if right/left level on the PA system matched player position on stage.
Stereo (and even Quadraphonics) IS used, but generally as a special effect, think the radio controlled model German bomber famously used by Pink Floyd, so recorded engine noise somewhat matched model plane position ove the audience.
Or Jimmy Page famous "playing along his own echo" when playing guitar with a bow, when echo was directed to the opposite side.
YouTube
As you see, both are very dated exampes, there must be some reason it didn´t catch up.
In this case, "so everybody in the audience hears the same"
Real Stereo imaging would be available only to 1/3rd or 1/4th of the Audience otherwise, those placed roughly in a centerline, while others would hear, say, "too much/too little guitar" or any other instrument, if right/left level on the PA system matched player position on stage.
Stereo (and even Quadraphonics) IS used, but generally as a special effect, think the radio controlled model German bomber famously used by Pink Floyd, so recorded engine noise somewhat matched model plane position ove the audience.
Or Jimmy Page famous "playing along his own echo" when playing guitar with a bow, when echo was directed to the opposite side.
YouTube
As you see, both are very dated exampes, there must be some reason it didn´t catch up.
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I've come to the same conclusion, that mono is the better solution. I've built 3 different boomboxes, all stereo. The reason? Didn't know better 😀 But now that I think of it, mono is more reasonable choice because you roughly use half the power, need half the volume but lose 3dB. I think the power consumption and size weighs more than SPL in this equation. Please correct me if I was wrong in my statements 😀
But one has to admit, that if you're new to DIY audio stuff, building a stereo system is more simple because you have so much bluetooth stereo amp boards available. Just connect speakers and battery, put them in some box and you're pretty much done.
But one has to admit, that if you're new to DIY audio stuff, building a stereo system is more simple because you have so much bluetooth stereo amp boards available. Just connect speakers and battery, put them in some box and you're pretty much done.
Yea, it's weird that there doesn't seem to be any bluetooth modules that have the ability to sum the channels as an option.
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