Information on the "subwoofer output" of my TV in regards to crossover

[NYCJay]

Hello everyone. I've put a few hours into searching for answers but came up short and was hoping some of you more experienced folks might be able to help. My TV (Mitsubishi LT-55146) has a "Subwoofer Output" RCA jack but the only information I can find in the manual is that it's a subwoofer output (surprise!) and that the TV has dolby digital processing, no specs on the jack itself. So my question is: is it a standard LFE 120HZ low pass situation or will I need a crossover between the TV and the power amplifier (does not have a built in crossover) to the passive subwoofer?
Something like this:

(TV Subwoofer Output) ---> (Power Amplifier that has no crossover option) --> (Passive Subwoofer)

do I need a low pass cros^sover here? Or is subwoofer output already .1 LFE signal?

Second question. If the amplifier doesn't have an "LFE In" jack, should I split the Sub Out cable with a Y adaptor to use both L and R inputs to amp?

Thanks for any advice you can share. I'm trying to get this project together and this is my first foray into power amplifiers instead of built in subwoofer plate amplifiers.

 

[lovinthehd]

While I don't really understand using the tv's speakers at all, first time I've heard of a sub pre-out on a tv. Agree there's nothing in the documentation I can find either regarding what frequency range it outputs....could be full range, could have a limit, hard to know unless you measure the output. What amp/sub are you using?

 

[WaynePflughaupt]

So my question is: is it a standard LFE 120HZ low pass situation or will I need a crossover between the TV and the power amplifier (does not have a built in crossover) to the passive subwoofer?

You have access to the same info that we do. If it’s not in the manual, it’s doubtful anyone will be able to answer your question. You won’t know if the signal is full range, or low-passed somewhere, until you connect everything and see. If it’s a full range signal, you’ll need a low pass filter of some kind.

Second question. If the amplifier doesn't have an "LFE In" jack, should I split the Sub Out cable with a Y adaptor to use both L and R inputs to amp?

Maybe I’m out of touch, but I’ve never seen an amplifier with a LFE input jack. Powered subwoofers yes, but not stand-alone amplifiers. You can use a “y” splitter if you have two passive subwoofers. If you only have one, there’s no reason to get a signal to the second channel that’s not going to be used.

Regards,
Wayne A. Pflughaupt

 

[NYCJay]

Thanks for trying guys. As for why I'm using the TV speakers it's because I don't own a reciever and the TV's 16 speakers are decent. I can't afford a receiver and speakers at the moment, lots of medical bills. Just trying to piece something together from craigslist on the cheap to replace my klipsch sub that just died. Looking at building my own enclosure from a parts Express kit and getting a used amp.

I'll just see what happens and worry about low pass if I need it.

 

[WaynePflughaupt]

Here’s hoping your health improves, Jay.

Regards,
Wayne A. Pflughaupt

 

[lovinthehd]

Thanks for trying guys. As for why I'm using the TV speakers it's because I don't own a reciever and the TV's 16 speakers are decent. I can't afford a receiver and speakers at the moment, lots of medical bills. Just trying to piece something together from craigslist on the cheap to replace my klipsch sub that just died. Looking at building my own enclosure from a parts Express kit and getting a used amp.

I'll just see what happens and worry about low pass if I need it.

Wow a tv with 16 speakers, didn't realize that, but they do probably need help from a sub. Having some sort of lowpass control, even if only an lpad, might be in order, tho, if they don't have a built-in filter.

 

[NYCJay]

Here’s hoping your health improves, Jay.

Regards,
Wayne A. Pflughaupt

Thanks Wayne. It's my wife actually. She just had her second kidney transplant. We have decent insurance but those $20 copays and Lyft bills add up fast.

 

[NYCJay]

Wow a tv with 16 speakers, didn't realize that, but they do probably need help from a sub. Having some sort of lowpass control, even if only an lpad, might be in order, tho, if they don't have a built-in filter.

Yeah the built in dolby digital sound system was one of the main reasons I bought it because it's basically an integrated sound bar that allows you to enter your room dimensions/shape and tv position so that it can reflect sounds for a mock surround effect. My wife doesn't care much about quality sound, she calls my subwoofer a "boombox", so it was my compromise to get decent sound with only needing a subwoofer. My Klipsch dying doesn't even bother her but having no sub for the lows and emersion is killing me lol.

 

[BMXTRIX]

If your subwoofer doesn't have a LFE input jack, then you should refer to the manual of the subwoofer to see which input you should use.

In my experience, if it is not clearly marked which input you should use, then the manufacturer typically allows you to use either input and it's just fine. Likewise, you could use a Y-cable, and that would also be just fine.

 

[Leemix]

I dont actually know but it would be strange if there wasnt a crossover for the LFE out unless its only the actual LFE channel thats ever sent there.
Maybe a mail to the manufacturer would let you know?

 

[lovinthehd]

Yeah the built in dolby digital sound system was one of the main reasons I bought it because it's basically an integrated sound bar that allows you to enter your room dimensions/shape and tv position so that it can reflect sounds for a mock surround effect. My wife doesn't care much about quality sound, she calls my subwoofer a "boombox", so it was my compromise to get decent sound with only needing a subwoofer. My Klipsch dying doesn't even bother her but having no sub for the lows and emersion is killing me lol.

WAF is tough on many systems

 

[KenM10759]

Was it a Klipsch sub that died? If so, which model?

The plate amps on most can be replaced with one very close to original. Those that can't, I've found creative ways around that. In replacing the sub plate amp with one from parts-express.com there are a lot of great choices, and some are well under $100.