Solved! How can I replace my subwoofer?

[Antares95]

Hi everyone, I'm not an expert so I don't know if what I'm saying is going to be correct.

I've got an audio system Logitech z906 which I really love. The only problem is that I don't find the subwoofer powerful enough for my tastes (some frequencies are not taken good by the sub) and I would like to change it.

I was thinking to take the subwoofer from JBL called GT Basspro-12 which is a 450 watts sub (150 watt RMS) to replace the sub. In theory this is a car sub but it really is what I'm looking for.

So my question is: is it possible to wire this sub to the 5 speakers and the amplifier of the Logitech? And if yes how to do it? Should I buy something to connect everything together?

Also, if it's not possible, which sub do you suggest to buy? I don't want to go for very expensive subs and the one I wish to take it's only 100 pounds or something like this.

Every part of the system is connected to the sub I have right now: speakers, amplifier, electricity.

Thanks in advance!

 

[Sonic Illusions]

Here's an idea: Shooting for the simplest solution, this should be pretty easy. The JBL has it's own amp, with high-level inputs. Since the amp module on the Logitech sub does everything (outputs to the surrounds and internally to the sub with crossover), you can remove the amp module from the Logitec, disconnect the wires to the sub-woofer driver and connect them to the high-level inputs on the JBL. You can mount the Logitec amp in a separate box or leave it in the Logitec sub enclosure. You can even have 2 subs; leave the Logitech driver connected and connect wires from the driver to the JBL. Please note that the crossover filters in the Logitec will make the crossover on the JBL pretty much useless, so you would leave the Low Pass control on the JBL at 200Hz and let the Logitec do the job of properly blending the sub with your system at the existing crossover point built into the Logitech system. Should work fine.

As for recommending another sub, you can do the same with any self-powered sub-woofer setup that has high-level inputs. Just keep in mind the power limits from the Logitech system. You don't want overkill on the sub. 200 watts would work well with the Logitech system.

 

[Antares95]

Here's an idea: Shooting for the simplest solution, this should be pretty easy. The JBL has it's own amp, with high-level inputs. Since the amp module on the Logitech sub does everything (outputs to the surrounds and internally to the sub with crossover), you can remove the amp module from the Logitec, disconnect the wires to the sub-woofer driver and connect them to the high-level inputs on the JBL. You can mount the Logitec amp in a separate box or leave it in the Logitec sub enclosure. You can even have 2 subs; leave the Logitech driver connected and connect wires from the driver to the JBL. Please note that the crossover filters in the Logitec will make the crossover on the JBL pretty much useless, so you would leave the Low Pass control on the JBL at 200Hz and let the Logitec do the job of properly blending the sub with your system at the existing crossover point built into the Logitech system. Should work fine.

As for recommending another sub, you can do the same with any self-powered sub-woofer setup that has high-level inputs. Just keep in mind the power limits from the Logitech system. You don't want overkill on the sub. 200 watts would work well with the Logitech system.

So what you are suggesting me is simply to disconnect the speakers wires from the back of the sub and connect them to the back of the JBL sub, right?
Or I have to connect them to the amplifier?

And one more question I forgot to write before: do I need to buy a power supply for the JBL sub? Because in many YouTube videos I see people with power supplies

 

[Sonic Illusions]

Yes, regardless of which powered sub you choose, you need to get the sub signal from the Logitech system's sub-woofer. This is the 2-wire connection inside the Logitech sub enclosure, which you'll connect to the high-level inputs on your 'new' sub. You can get rid of the Logitech sub enclosure and still use the multi-channel amp (which includes the filtered sub signal) to drive your surround speakers and provide the sub bass signal to your new sub.

To use the JBL unit, yes, you would need a 20 amp 12V (13.8) power supply. Or you can simply get a powered sub, which plugs into an AC outlet, which I'd recommend.

 

[Antares95]

Yes, regardless of which powered sub you choose, you need to get the sub signal from the Logitech system's sub-woofer. This is the 2-wire connection inside the Logitech sub enclosure, which you'll connect to the high-level inputs on your 'new' sub. You can get rid of the Logitech sub enclosure and still use the multi-channel amp (which includes the filtered sub signal) to drive your surround speakers and provide the sub bass signal to your new sub.

To use the JBL unit, yes, you would need a 20 amp 12V (13.8) power supply. Or you can simply get a powered sub, which plugs into an AC outlet, which I'd recommend.

So to recap, I have to disconnect the 5 speakers wires (which make up a total of 10 wires because these wires are then divided into two) and connect them to the JBL subwoofer, then connect the Logitech amplifier to the JBL subwoofer as well and in theory the Logitech system is connected to the new sub and also I have to buy a power supply to power the subwoofer which will also power the speakers.

My question now is:
Which power supply do you recommend?
What to do with the JBL amplifier?

Sorry for all these questions but I'm a total noob when it's about audio systems.

 

[Sonic Illusions]

The amp on the Logitec sub cabinet drives all of your surround speakers. Regardless of what sub you use (even the Logitec), your connections from that amp to your surround speakers will still be the same. No speakers will be connected to the JBL. The subwoofer will not power any other speakers. If you must use the JBL, then you need to feed a signal into it. That signal is the same that's connected to the internal Logitec sub. That's why the easiest way for you to boost your bass SPL is to take that signal (2 wires connected to the woofer inside the Logitec sub enclosure), disconnect it, then splice wires for the desired length for connection to the high-level inputs on the JBL or any other powered sub you choose. You don't need heavy gauge wire, because they won't be carrying much current. That's the simplest way I can suggest. Then, the Logitech sub enclosure becomes just a box, UNLESS you want it's internal woofer to contribute. In that case, leave the internal woofer connected and splice the wires to your new sub onto that connection, run them through the port or (best) through a drilled and sealed hole in the enclosure.

Power supply:
https://www.alliedelec.com/product/...Vno2zCh3SwAUqEAQYBiABEgJ5R_D_BwE&gclsrc=aw.ds

What to do with the JBL amplifier? It powers the sub it's designed to.

 

[Antares95]

The amp on the Logitec sub cabinet drives all of your surround speakers. Regardless of what sub you use (even the Logitec), your connections from that amp to your surround speakers will still be the same. No speakers will be connected to the JBL. The subwoofer will not power any other speakers. If you must use the JBL, then you need to feed a signal into it. That signal is the same that's connected to the internal Logitec sub. That's why the easiest way for you to boost your bass SPL is to take that signal (2 wires connected to the woofer inside the Logitec sub enclosure), disconnect it, then splice wires for the desired length for connection to the high-level inputs on the JBL or any other powered sub you choose. You don't need heavy gauge wire, because they won't be carrying much current. That's the simplest way I can suggest. Then, the Logitech sub enclosure becomes just a box, UNLESS you want it's internal woofer to contribute. In that case, leave the internal woofer connected and splice the wires to your new sub onto that connection, run them through the port or (best) through a drilled and sealed hole in the enclosure.

Power supply:
https://www.alliedelec.com/product/...Vno2zCh3SwAUqEAQYBiABEgJ5R_D_BwE&gclsrc=aw.ds

What to do with the JBL amplifier? It powers the sub it's designed to.

Hi again, so looking on the internet I found two different subwoofers that could fit to my Logitech system.
I'm talking about the Polk Audio PSW505 and the BIC America F12. Both of them have the power I'm looking.
Which one of them do you think is better? How can I connect one of them to the 5 speakers and the amplifier?

 

[Sonic Illusions]

Hey there! Again, you still need to get a signal to the sub-woofer, regardless of brand (as long as it has an amp). You'll still need to make the connection from the back of the Logitech multi-channel amp (inside the box-to the Logitech woofer).

POLK AUDIO for sure! -3db @ 28Hz., 300W continuous. You'll be very happy with that one.