How to add subwoofers to old integrated amplifier?

[agiletiger]

I just got a pair of the RSL Speedwoofer 10S MkII. I need to hook them up to an older amp that doesn’t have any subwoofer out nor any preamp out. I can get one of them to work by hooking up speaker wires to it.

What has not worked is any of the ways the sub manual suggested in linking the two subs together: Connecting the line out(s) to the line in(s) via RCA. I tried both, just left, and then just right. Nothing.

I know that I can go the speaker wire route but that looks like a pain. I got 12AWG wire upon recommendation of this forum and it’s getting crowded!

Anything else I can try? For example, there is a tape loop. Would the tape out function as a preamp out or is that a no no? Or is there something I am doing wrong with connecting the two subs via RCA?

PS - I do not want to buy any more equipment at this time. I have a miniDSP flex ordered but who knows when that’ll get here.

 

[agiletiger]

Amp is a Rega Brio 3 if that matters.

 

[FrantzM]

I believe the RSL also have speakers inputs. You connect your amplifier speakers output to the each subwoofer and the speakers to the subwoofer’ speaker output.

 

[DanielT]

Connect a high to low convector, it together with the other speaker cables into the amplifier. Then you have via the RCA. That signal to don subwoofer amp.

It works. A converter costs around $ 15. It is a passive gadget, just plug in, honk and drive.

Here fiddles with a converter plus a little other mischief.

Project sub output

An old amplifier Luxor 7082 A. I connected a high to low level converter on the speaker outputs, to be able to connect an active subwoofer. Connected in parallel, together with the cables to the speakers. The converter: My friend said: why not take the signal directly from the pre amp section...

audiosciencereview.com

 

[anotherhobby]

Tape loop won't have volume control. Since you have a miniDSP Flex on the way, for now I'd just put one sub next to each speaker, then connect the speaker level inputs on each sub to the corresponding terminals on the speaker it's next to. That'll save you from having to monkey around too much, and then you can do it all right when the miniDSP shows up.

 

[anotherhobby]

Also, if your subs are right by the speakers, leave the subs phase at 0, set the crossover to match your speakers roll off as best you can, and adjust volume levels to match as best you can. If you have a umik-1and REW it should be pretty trivial. If not you could even get close with a cheap phone app.

 

[DanielT]

Aha sorry, I missed. Partly miniDSP Flex then two subwoofers.

Without miniDSP (which you have) , for general information. Two sub. Split RCA:

Pre out + RCA splitter

I will test this today: Pre out from my NAD receiver, split the signal and feed it to two different amplifiers. One of these amplifiers (a low powerd tube amp) will take care of my XD 125 compression drivers. The other amplifier (HK 670) will take care of the bass element in a couple of other...

audiosciencereview.com

Good luck.

 

[pjug]

I know that I can go the speaker wire route but that looks like a pain. I got 12AWG wire upon recommendation of this forum and it’s getting crowded!

It isn't clear if you are running heavy wire to the sub but you don't need to. Something like 24AWG is perfectly fine. Heavy gauge to the main speakers but powered subs inputs are high impedance so thin wire is OK.

 

[DVDdoug]

I know that I can go the speaker wire route but that looks like a pain. I got 12AWG wire upon recommendation of this forum and it’s getting crowded!

You don't need heavy-gauge wire but you will have to combine it with your existing wires (if your amp only has one pair of speaker-outs).

The speaker input goes into the sub's amplifier (after being attenuated) and it will be much higher impedance than a direct speaker connection so there will be very little current and you can use "thin" wire.

 

[freemansteve]

It read like you connected line in to line out on the sub! But I guess that's not what happened.

As said, you can run skinny wires to the big connectors on the back of each sub in parallel to the wires going to each of your main speakers. I'm sure it is a high impedance input.

 

[agiletiger]

It looks like speaker wire is the way to go. Any disadvantage in using a thick wire other than it being a PITA?

 

[agiletiger]

Also, if your subs are right by the speakers, leave the subs phase at 0, set the crossover to match your speakers roll off as best you can, and adjust volume levels to match as best you can. If you have a umik-1and REW it should be pretty trivial. If not you could even get close with a cheap phone app.

I have a umik-1 on its way with the miniDSP. What cheap app should I use until then?

 

[ThatM1key]

Subwoofer High-Level in/outs or use "Tape Out". "Tape Out" should always output a signal but I consider it worse than daisy chaining (High- speaker wire (High Level). The reason why I consider "Tape Out" worse is because of volume control, you'll always have to reach the subwoofers volume control to match your speakers volume output. When you use high-level in/out's, you get matched volume with your speakers. Using high-level in/outs doesn't rob you any speaker power at all.

Here is a terrible drawing I made of using high-level in/outs or commonly called daisy-chaining.

Edit: You have to level match your subwoofer volume to your speakers once and also set the crossover on the subwoofer to your preferred frequency. Some people crank the "Bass" knob all the way down on the amp, so the speakers don't have to bass and they simply turn the subwoofer volume up. I wouldn't do this because you'll increase increase noise and distortion on the subwoofer.

 

[anotherhobby]

I have a umik-1 on its way with the miniDSP. What cheap app should I use until then?

Just search for audio spectrum analyzer on whatever phone platform you have. I've only used REW, so I can't recommend a specific one.

 

[agiletiger]

Long overdue update: Everything is hooked up and working. I set the volume and low pass filter at 12:00, the latter probably at around 100Hz. It’s close but I don’t want to mess with it anymore until I get my miniDSP in. The subwoofer is a tad behind the sound from the speakers which I’m just living with for now. Now where is my miniDSP flex?

Thanks again everyone!