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Best method to connect subwoofer to amp

I just finished a great post about my speakers and amp clipping sensitivity, impedance etc. highly educational, as I am a rookie in this hobby just starting out. One recommendation coming out of that discussion was to contact my manufacturers. I have a Jamo c 80 sub (1800 watts and with an adjustable crossover from 0 to 200hz) for two-channel stereo. the c80 has binding posts for speaker cable connections for spades and banana plugs. The c80 also has" Line in left/LFE and right.. My integrated amp is a Technic SU-G700 and its manual says to connect the sub to its pre-out left and right connections.
Listening to Paul McGowan ( PSAudio poobah) he says the best way is to run speaker cables from my amp to the speaker terminals on the JAMO which is my current practice. He says this ensures the same signal going to my main speakers (Canton 9k stand-mounted) and the sub are the same helping them disappear. As noted I am currently using that method and indeed my subs vanished.
However when speaking to JAMO the rep said the best way is to connect the amp and sub is through the Preout of the amp to the Line input Left /LFE and right of the sub, my Technic manual also says this.
There is no high pass filter involved in my system the integrated amp sends the full signal through the pre-out not confirmed by Technic but from what I’ve read. I mention this as my amp is only 70 watts and I would have loved to separate the bass to be driven exclusively by the sub so my main speakers could be relieved of that duty and as I understand it two benefits would occur 1 my stand-mounted Cantons would no longer have to play the bass and 2 more power would be available for the cantons.
It should be noted the canton9 k have two sets of speaker terminals on set for medium and high frequencies and another set for bass. I will not be buying a separate highpass filter at this time.

Given the above which is the best method (for musical benefits) to connect the sub or does it even matter which of the two options I use given my system?
Is one method safer to use than the other?
Am I missing anything I should be aware of?
Thank you for your help
Scott


scott22
imhififan's avatar
imhififan
2,217 posts
 
My goal is to stop the low bass from playing on my stand-mounted speakers so they can concentrate their efforts on the mid bass on up.
If that’s your goal, a high pass filter is a must!
Since your integrated amp not possible to insert a line level high pass filter, your only option is to insert a pair of speaker level high pass filter between the speaker and integrated amp speaker output.

SU-G700 speaker output --> speaker level high pass filter --> Canton 9K

You can find some inexpensive speaker level high pass filter at Parts-express for experiment:

https://www.parts-express.com/100-hz-high-pass-4-ohm-crossover--266-460

For best result, I suggest Bi-wire configuration:
Disconnect the jumper bars from the Canton 9K speaker terminal,
connect the speaker level high pass filter input to integrated amp speaker terminals, output to Canton 9K low frequency terminals,
connect the Canton 9K high frequency terminals direct to integrated amp speaker terminals, so the high frequencies will not go through the speaker level high pass filter.

If you like the result of this setup, you can upgrade the capacitor in the speaker level high pass filter to Film Cap to further improve sound.

https://www.parts-express.com/pedocs/tech-diagrams/266-460--crossover--schematic.pdf
scott22 OP
266 posts
 
Imhifian  
Thanks for the advice! I will definitely look into this. I appreciate your time.
imhififan's avatar
imhififan
2,217 posts
 
IME, I always found that a good high pass filter greatly improve dynamic and clarity on small 2 way monitors.
mkgus's avatar
mkgus
324 posts
 
If you’re going with Paul McGowen’s approach, I think the best way to do it is to grab the signal off the speaker amplifier binding posts, drop the voltage drop, and send it through a DSP and then to the subs. This lets you shape the bass waves which is an audiophile requirement for low bass in small listening rooms.

You may also find that high passing the mains increases overall sound quality, especially at higher output levels.
mijostyn's avatar
mijostyn
8,570 posts
 
Scott, I am also in the Northeast. If you are over 65 just keep your distance from others. Skip the concerts and those late nights at the bar for now. This is all going to blow over. I think the main attraction here is they way this is permanently going to change the way we live. People who never shopped online are now addicted to it. Malls are going to converted to nursing homes, retailers are disappearing. People working from home are more productive! Sure, if you done have to waste 3 hours a day in the car. Downtown real estate is plummeting in value. Who needs a big expensive office. 
Anyway, sad to hear you sold your Snells. Those were great speakers.
If you want to increase your output get a crossover like the JL Audio unit and a second subwoofer. This will allow you to raise the crossover point without harming the image as long as you place the subs correctly. I cross over at 125Hz. It is easier to match subs with a higher crossover frequency because the wavelengths are shorter. The low crossover points that you see being used work better with one way crossovers and single subwoofers. It adds low bass but does nothing else for the system. Using a 2 way crossover, two subs (or more) and a higher crossover point reduces distortion in the main speakers, increases headroom and gives you much more flexibility in adjusting the bass to your preference. 
  
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