LFE vs High-level subwoofer connection, for FIDELITY

>> "Here’s a screenshot filtered below 100Hz. There’s a fair amount of energy down there."

Dude you’re listening to SoundGarden?  You do realize that there’s kick drums and a bass guitar going during that solo right?  lol.  What is the time stamp you’re listening to?  

If you analyze the intro which doesn’t have other instruments you’ll see what I’m saying.  Notice that peak at 82 hz?  That’s a low E.  If you cross reference the guitar tabs, you’ll see that they play an open E string sometimes.  That’s as low as this guitar is going to play on this track.  The stuff below it is just junk, it’s registering as low as 1 hz on the intro, just not reality... distortion artifacts or something, it’s never going to go away if there’s anything playing at all.  Most of what you hear on a guitar is going to be the second harmonic.  Seeing the biggest fattest spike start up at 164 hz isn’t a coincidence.  

 

 

@paducahhometheater 

Dude you’re listening to SoundGarden?  You do realize that there’s kick drums and a bass guitar going during that solo right?  lol.

Just the right channel: I hear a lead guitar solo, maybe rhythm, and cymbal that shows far in the high frequency. If there's sheet music showing otherwise, let me know. Besides, play the 80Hz test tone when in doubt. That's really the objective, to try to localize 40Hz-100Hz, because as mentioned earlier, music has stereo effects and dynamics that are lost if the signal is sent in mono to a subwoofer.

 

The stuff below it is just junk, it’s registering as low as 1 hz on the intro, just not reality... distortion artifacts or something

Theory does not seem to reflect reality which probably includes boost and intended or unintended artifacts during mixing. You'll be surprised even with rock you'll see lot of sub 40Hz bass despite how low some instruments theoretically go.

 

Why on earth would you want your mains being slammed with 6 hz from a powerful external amplifier?  Serious question.  There's tons of infrasonic material out there today.  You're killing headroom, adding distortion, introducing the risk of damaging speakers, it's just not a good thing.

The range in question is near 40Hz-100Hz and speakers, particularly full range, are best suited in this range. Many subwoofers crack above 150Hz.

 

wants to use a high level input from their amp.... why not use a Jensen transformer?

That was definitely a consideration to also eliminate unrelated ground loops, etc.

 

I have yet to see factory verbiage saying a typical receiver whether it be cheap or flagship will reroute the LFE to the mains, it's all second hand forum posts or whatever as the source.

Movies used to be mixed in full range without subwoofers. I've seen it in Pioneer literature somewhere. Denon has updated literature here: https://manuals.denon.com/AVRX4800H/NA/EN/DRDZSYimemaleu.php

" I have yet to see factory verbiage saying a typical receiver whether it be cheap or flagship will reroute the LFE to the mains, it’s all second hand forum posts or whatever as the source. "

Now you have:

Yamaha RX-Z9 User Manual, Page 78:

Bass Out (Bass out)

LFE signals carry low-frequency effects when this unit

decodes Dolby Digital or DTS signals. These low-

frequency signals can be directed to both front left and

right speakers, and to the subwoofer (which can be used

for both stereo reproduction and sound field programs).

Choices: Both, SWFR, Front

"Select Both to direct LFE signals to the subwoofer.

Front L/R low-frequency signals are directed to both

the subwoofer and front channels, and all other low-

frequency signals are directed in accordance with other

speaker settings."

 Select SWFR if you connected a subwoofer. The unit

directs all LFE and low-frequency signals in

accordance with other speaker settings.

• Select Front if you have not connected a subwoofer.

The unit directs all low-frequency and LFE signals to

the front speakers (even if you have previously set

Front to Small in Speaker Set).

• Select Large if you have large front speakers. The unit

directs the entire range of the front left and right

channel signals to the front left and right speakers.

• Select Small if you have small front speakers. The unit

directs the low-frequency signals of the front channel

to the speakers selected with "Bass Out".

https://www.manualslib.com/manual/443477/Yamaha-Rx-Z9-Av-Receiver.html?page=78#manual

I have Martin Logan CLS 1, a full range electrostatic, and dual  Martin Logan Dynamo 10 subs.  I use the balanced output on my preamp which is run to a JL audio CR-1 active crossover that splits the signal around 50 Hz for both the mains in the subs.  It works well and blends the subs and the main speakers seamlessly.

I was advised not to connect using subs using the speaker terminals (I use dual mono tube amps)

>> "The range in question is near 40Hz-100Hz and speakers, particularly full range, are best suited in this range. Many subwoofers crack above 150Hz."

This is two different conversations.  I'm talking about generally speaking, not your guitar solo, the idea that you want to send powerful 6 hz sine waves to your mains with a high current external amp, at the levels anywhere near what it was intended to be to pull off the effect properly, is daft, for multiple reasons.