Posted by triamp (A) on September 20, 2021 at 04:35:24

Some Sony TV's like my Sony XBR65A9F set that I have use the screen itself as the TV's speaker. They've got some kind of actuators behind the screen somehow... Now I had not used the TV's "screen speaker" until recently when a project to replace my A/V equipment cabinets left me without my main system for a while. So I was using the TV's "screen speaker" to watch TV and it worked OK. Then I turned on some background streaming music and - WHOA! - I found it sounded pretty good. It was stereo. And Sony does have some kind of small cone woofers in there too. There was no actual bass, but there was decent lower midrange which gave an overall fairly "full" sound... it blew my mind that this sounded as decent as it did. I ran an FR graph of it and was again amazed at the engineering Sony did on this - have a look at the FR plot. Now it's not reference quality or anything like that but when you consider that the sound is coming from a TV SCREEN.....

There are a pair of small cone-type "subwoofers" inside the chassis, I think the FR plot shows that the screen starts to roll off below about 300 Hz and then you get some support around 70~100 Hz from these cones. I think the rising amplitude below 40 Hz in the plot is some artifact, a truck drove past as I was making the measurement, or the HVAC was running or something. There's no way this TV set had any kind of output below 40 Hz! ( HAHAHAHA )

Sony also provides a pair of speaker binding posts and a menu item so you can drive the screen-speaker with an external amplifier and use it for center channel speaker in a surround setup. It appears that these binding posts do not connect directly to the actuators but to the electronics in the TV; when I connected the - lead from my center-channel amp to the binding post / banana jack on the TV, the TV made a moderately loud 60 Hz buzz from the "screen-speaker" which stopped when I connected the + lead. So the TV is apparently taking the output from my center channel amp and using that to drive it's internal amplifier - and it seems likely that there is some kind of EQ too in there.

This scheme works very well in my surround setup. If I just turn the TV on, the set will play the TV sound from the "screen-speaker" (in stereo) but when I turn on my Emotiva UMC-200 surround pre-pro, the TV "sees" that event through HDMI and automatically changes to "external audio system" mode, which looks to that pair of binding posts for the signal to drive the screen-speaker instead of the TV's audio. The Sony uses the Android TV operating system, which is pretty sophisticated and works pretty well for this kind of thing.

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Science doesn't care what you believe.

Edits: 09/20/21   10/21/21   10/21/21   10/21/21