Help with details related to different ways of hooking up a Subwoofer to AVR (budget diy)

NewGuy781

Novice Member
Hello folks!

I need quick help with details related to different ways of hooking up a Subwoofer to AVR (budget diy). Any corrections/clarifications would be great. Might be a quick one… to answer :D

Note: I think I have found a couple half/answers in old threads, but I don't think they apply to me once I consider the differences between the component specifications like AVR limitations/connexions and audio that will be used (dolby digital, dolby Prologic, stereo, etc).

My goal:
To set things up in a way that I can use the subwoofer for both 2-channel and multichannel, and that I don’t need to be re-plugging things around.

My stuff:
  • AVR: Yamaha RX-V430 RDS
  • Subwoofer & speakers (5.1): Polk Audio RM6750
  • Speakers for music (stereo): B&W DM560
  • A-B Switcher

My issue:
The manuals of my AVR and subwoofer(and speaker system) give me conflicting setup instructions.

So these are the components I want to connect properly and respective instructions:

-Speakers for music (stereo): B&W DM560
No instruction conflict here (I'm using an a-b switcher), just added the freq. resp. for cutoff related information 65Hz – 20kHz ± 2.5dB

-AVR: Yamaha RX-V430 RDS
The AVR manual says that subwoofer should be connected to AVRs subwoofer pre-out, then speakers to their respective outputs on AVR (A-B switcher between both sets of speakers), and that LFE cutoff is locked at 90Hz with this AVR; which seems a bit too low considering the B&Ws lower freq. resp. is at 65Hz, and I have read there should be a healthy “distance” between speaker & sub’s roll-off (not sure if I used the correct terms, sorry).
Screen Shot 2021-04-14 at 15.17.22.png

-Subwoofer/speakers: Polk Audio RM6750
This powered sub has speaker level input&output (not sure if its = high level input), and a lowpass filter from 80-120Hz, and the manual gives me 2 options:
1. From AVR’s pre-out -> sub’s line input , and AVR settings on sub-ON & x-over to 120Hz.
BUT my AVR is locked at 90Hz.
2. From AVR’s front speaker output -> sub’s speaker level input, and AVR settings on sub-OFF.
BUT it also specifies that opt.1 is for dolby digital and opt.2 for dolby Prologic and stereo.
Screen Shot 2021-04-14 at 18.51.16.png


Screen Shot 2021-04-14 at 18.50.42.png


My questions: I would be using all formats (dolby digital, dolby Prologic and stereo) depending on source, and I would like to be able to set the x-over/lowpass at whatever works/sounds best via the Sub x-over knob… but…
What do I give prevalence to, the AVR guide or Speaker guide?
If Speaker guide prevails, would opt.1 or opt.2 limit me at all? (I found weird the differentiation of formats depending on hookup)
Are there specific set backs depending on hookup, except for lowpass control?
Am I complicating/worrying too much due to formats because any of these connections would provide all audio formats? :facepalm:


Thank you guys in advance for your help! :thumbsup:
 
Last edited:

NewGuy781

Novice Member
My guess 1: From AVR front speaker out (avr setting sub-off) -> sub’s speaker level input, and then from sub’s speaker level output -> A-B switcher -> B&W speaker & 5.1 front speakers. (though it seems this would give me "5.0", and I'm not sure what low freq. sacrifice this entails if any at all 🤔)

My guess 2: AVR guide prevails, I sacrifice "only" lowpass control, and I don't truly loose much.
From AVR pre-out (avr setting sub-on)-> sub’s line input, and then A-B switcher from AVR’s front speaker output-> B&W speaker & 5.1 front speakers.
 

Joe Fernand

Distinguished Member
AVForums Sponsor
Folk often get hung up on all manner of ‘technicalities’ when the simple solution is to hook the system up and have a listen to it and then have a twiddle with the settings. Most of the lab ‘specs’ get thrown out the moment you put kit into your room.

For AV playback start with the Sub crossover set to bypass and experiment with the AVR crossover setting - once you get that set you can have a play with also using the Sub crossover.

For stereo playback you may find you prefer running the B&W’s without the Sub no matter if you use High (Spk level) or Low (Line level hookup) as getting the sub integrated with the B&W’s could be more challenging than using the Sub with the AV spks.

A low cost SPL meter or an App on your phone is a good investment when trying to balance your AV speaker levels - Home Theater SPL - J.S. Technology Ltd

There are no rights and wrongs - simply experiment and decide what works best for you.

Joe
 

NewGuy781

Novice Member
Thank for the reply :)
A low cost SPL meter or an App on your phone is a good investment when trying to balance your AV speaker levels - Home Theater SPL - J.S. Technology Ltd
Noted, I will look for one for when I experiment.

For AV playback start with the Sub crossover set to bypass and experiment with the AVR crossover setting - once you get that set you can have a play with also using the Sub crossover.
What do you mean by setting sub crossover to bypass? Is it something I have to change on the physical knobs on the back of the subwoofer? Sorry, Im not familiar with with what this means. This is the diagram of what is on the subwoofer:
Screen Shot 2021-04-15 at 20.07.22.png


The AVR manual says that the crossover is locked at 90Hz, so I guess im out of luck with this part of the experimenting 🤷‍♂️

Screen Shot 2021-04-14 at 15.17.47.png
 
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NewGuy781

Novice Member
Sorry, one more question if you don't mind. I will experiment I promise 😇 I just want to learn a bit in the process.

I recall what you mentioned about specs going out the window once in the room, with that in mind, would a gap of 10Hz in the lower end of the frequency response matter sound wise with this setup?
I ask because yesterday I noticed on the specs of the 5.1 speakers that their supposed (lab?) range is from 100Hz-20kHz. The set cutoff of the AVR is 90Hz, so does that mean that whatever plays between 90-100Hz gets "lost"/inaudible**?
So maybe this would mean that theoretically it would be better to connect via speaker level input?

**I understand from graphs that in speakers the sound does not just disappear, it rolls off in a slope (sometimes steep), so depending on the steepness even though it does not disappear, its not quite audible either.
 
Last edited:

Joe Fernand

Distinguished Member
AVForums Sponsor
Sub - start with the Low Pass Rotary dial set to 160Hz, that effectively bypasses the filter.

AVR - has pretty rudimentary bass management, you are going to have to have a play with the settings in stereo and surround sound mode.

Joe
 

NewGuy781

Novice Member
Hello sorry for the delayed reply. Thanks for the tips :thumbsup:
I experimented this weekend and this is what I found:
(For anyone finding this tread, maybe it helps)

Turns out that for this type of situation (AVR crossover "locked" at 90Hz), the best outcome was to connect it following 5.1 speakers' manual and then use the low pass filter on the subwoofer. I went ahead and just followed the last tip setting the Low Pass Rotary dial to 160Hz. At least for movies (5.1) this worked best. Connecting the sub straight to AVR's pre-out simply lost umph and wow-factor 🤷‍♂️.

For music (2.1) however, after I change via the switcher to the B&W Speakers (not connected to sub spk-line outs), I still have to connect sub to preout on the AVR, otherwise the sub does not "participate".

Oh well, I guess those are the compromises with cheaper setups, so I will look into upgrading the AVR later.. but I'm happy for now. :D
 

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