Connecting ACTIVE speakers with no Sub out to an ACTIVE Subwoofer

kalelzkryptonite

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Hi All, I had a question regarding sub woofer connections and hoping to get some answers so that I can clarify my understanding.

What I am struggling to understand is how to connect an Active powered Speakers to an Active Subwoofer, in a case where the active speaker doesn't have a sub out. Please note I don't want to use an AMP or a Receiver as I have no space. I need my TV sound to drive the system.

Can I provide the sub woofer with Line level inputs from the TV directly and then have a line level out to my active speakers from subwoofers? Will that setup work?

1. I want to pair the following models if that helps in answering the question -
Active Bluetooth Bookshelf Speakers D300 - Swans Speakers + SB-1000 Pro

The above sub has both line level Inputs and outputs.
So my TV ( LG OLED B8 ) connects to the Subwoofer's Line Level Input
Line level out on subwoofer to (Inputs on Swans bookshelf speakers ).

2. How about if I want to connect a sub with no Outputs like this one?

In this case can i use a Y splitter from TV out to connect to both speakers and my subwoofer inputs?


Hope this is enough information to get some inputs/suggestions, any help is appreciated and apologies if it made no sense :p

Thanks
 
Are you wanting 2 speakers and a sub? What outputs does your TV have?

And what is your source for the content you're watching - is it just freeview on the TV?
 
Are you wanting 2 speakers and a sub? What outputs does your TV have?

And what is your source for the content you're watching - is it just freeview on the TV?
Yeah 2 powered speaker and a sub. TV has a 3.5mm and optical output.

Yeeah pretty much TV is the main hub for sound - netflix, you tube etc etc
 
Something like this from the optical output - so long as you don't mind using a seperate remote for the volume control: Amazon product ASIN B07G71BG3V
Or you could use the headphone output socket. To split to the sub, you will need to find a sub with left / right inputs and then just use Y split leads to split the left and right outputs to the main speakers and sub. You then just use the gain control on the sub to balance the level against the main left and right speakers.

The only drawback with this arrangement is that you are sending the sub signal to the mains as well. Not always an issue, but you might be working the mains harder than you might like.

Otherwise, you will need an AV processor, but it sounds like you don't need this if you are only looking at stereo and a sub in any case.
 
Something like this from the optical output - so long as you don't mind using a seperate remote for the volume control: Amazon product ASIN B07G71BG3V
Or you could use the headphone output socket. To split to the sub, you will need to find a sub with left / right inputs and then just use Y split leads to split the left and right outputs to the main speakers and sub. You then just use the gain control on the sub to balance the level against the main left and right speakers.

The only drawback with this arrangement is that you are sending the sub signal to the mains as well. Not always an issue, but you might be working the mains harder than you might like.

Otherwise, you will need an AV processor, but it sounds like you don't need this if you are only looking at stereo and a sub in any case.
Thanks mate for the response, understand that with a splitter the Low frequency will go to both Main speaker and the sub.
Sound wise that's not an issue, meaning not too muddy bass?

I was thinking have having a TV output to an active Sub and then Line out from Sub to Active speaker. Will that setup work and solve the problem that exists with a Y splitter? i.e sub keeps the low frequency and sends rest to active speakers?
 
If you can find a sub with filtered line level output. I think Genelec and Meyer do them for professional applications but not sure about any domestic subs with the capability.
 
I think they do . See Wharfedale SW150 which I found to have line level outputs ( I am not sure what you mean by filtered line level out though and if that is any different).

Have attached a pic. It has speaker level inputs too which i am assuming will be a pre-amped signal from a receiver. ( Probably the most ideal way to hook these up).

I think this will work, but since i have never done a setup like this wanting confirmation/inputs from experts before i put my coin through.
 

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By filtering, I mean removing the sub signal before sending the rest of the signal to the mains - exactly as you describe.

I'm pretty sure that the sockets on that sub are just loop outputs, so don't have any filtering applied. Basically they build the Y split into the sub for you. This will be tidier than Y splits - provided the Sub is somewhere close to the main left and right speakers and you can run the cables in a sensible fashion.
 
i get you now, So in this case too , both my low frequency will be played on active bookshelves and subs. I was thinking the crossover knob can act as a low pass filter, but i think that's a no.

However even if that works and is tidier, sounds okay for my requirements.
 
Yep, should be fine. You might end up setting the sub frequency a little lower than you might have done of you were properly filtering, that's all.

Best approach I find is to find out the main speaker frequency response, look at the low number- EG: 50Hz, then add about 30% to this number - so about 70Hz, and use this as the starting point for the crossover.

Then, while playing a reasonably bass heavy track, slowly advance the sub gain level until you can clearly hear it. At this point, back it off until it just disappears. This is about the right level and to demonstrate just how much it's still doing, switch the sub off for a moment and you will be amazed!
 
Got it! Guess i always kind of misunderstood subwoofers in a way. Optimizing the sub should completely change the experience.

FREQUENCY RESPONSE38Hz-20kHz (±3dB, free space), that's the response i see of Swans D300, will adjust accordingly :).

BTW - Final question if you are too kind :) - I have an LG OLED B8 with a 3.5 mm output , can i directly feed that into the Active Sub then?
I also have an optical out and people have recommended a mini DSPs which i think will work , still just wanted to understand if i can do without it.
 
The 3.5mm output will work fine.In terms of voltage, headphone and line level are about the same, and lots of people do this.
 
Thanks noiseboy72 for your response, i think that pretty much answers my questions.
Hi I'm also having the same scenario as you, but have a laptop instead of a TV. How did you end up approaching this and which sub did you end up purchasing?
 

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