Subwoofer gain settings

Hey all, noob here but I've looked around the forums quite a bit and wanted to clarify the info I've read. I've got a Yamaha Aventage RX-A680 along with a 5.1 set up of Yamaha entry-level satellites and an 100W 8" ported sub. Not the greatest, but can actually provide a nice clear sound with the upgraded AVR in my small room. Anyways, I am wanting to maximize the bass I can get out of this small sub by using more gain and less juice from the receiver. I recently moved the sub after realizing the port was on the right side and not the back, so it was hitting a wall and getting nasty reflections at near-reference levels. After doing the crawl and finding ideal placement that still ran a strong WAF, I ran YPAO and with the gain knob on the sub around 2:00 it set the sub at -5db (+/- 10db total) in the Level screen with the other speakers., which seemed like a good starting point This receiver has another menu with a separate subwoofer trim of +/- 6db for making on the fly adjustments. Ideally, would it be better to turn the gain on the sub up and run the trim lower without adjusting the overall volume level? Or is going positive on the subwoofer trim ok as long as the overall volume stays at a net 0db or less (say I chose to add up to 5db of extra trim without affecting gain, resulting in a net 0db level)? I want to maximize gain and minimize distortion and just wasn't sure of the overall relationship between the speaker volume level that YPAO sets and the separate subwoofer trim (Yamaha's documentation of subwoofer trim reeks of marketing BS). Thanks for any and all help!
 

swiftpete

Distinguished Member
Leave the gain dial where it is and if you want a bit more bass turn it up 2 or 3 on the avr. If you get a good enough sub you won’t need to do that though. Sounds like you need an upgrade!
 

Conrad.

Well-known Member
You're right that it's a balance between the two controls. They're both there for when the other end doesn't have a matching half (passive speakers, for example).

This is also the reason why on the sub it's a gain control and not a volume control, it's designed to gain match the sub with the output from the source and rest of the system. If you were using a fixed line output from the AVR or speaker level inputs on the sub you'd need the gain on the sub to match it to the rest of the system.

Your theory is right, you can decrease the level in the AVR and increase the gain on the sub. What you're doing is dropping the output voltage from the AVR and then amplifying it in the sub amp (I think). It doesn't sound like it'll give you much benefit though. If anything you want a stronger signal that then is less amplified in the sub as that should improve the signal-too-noise ratio.

Between -6 and 0 is about right for a sub level in an AVR. 2:00 is quite high for the gain on the sub, but it's a small sub and, being in Seattle, you likely have a good sized room. I think all in all your settings are about right. You can go up to 0 and adjust the gain accordingly, but it's generally not advised. I think you can run into clipping and headroom issues if you listen at volume with 0 or higher as your levels. Someone with more AVR experience than me will hopefully pick that up.

The additional trim control is for when you want to turn the sub up or down for a specific session without adjusting the overall relative levels. I suspect that gets set back to 0 on a restart.
 
Thanks for the input! So after checking again, the volume knob on the back of the sub is actually a volume knob lol. That being said, I reran YPAO and it set the overall AVR level at -9.5, just shy of the -10 limit. From here, I added 6db to bring it up to -3.5db and moved the sub trim to -6b to even it out overall. It sounds decent here, but after adding 2db to the trim (now at -4db), this thing really wakes up and provides a good amount of output without distorting! Knowing that the sub is a volume knob rather than a gain knob, did I do a bunch of extra work for nothing? If so, that is fine as I am happy with the result now lol
 

Conrad.

Well-known Member
I think those steps sound ok. Balancing the levels like that is ok. The only question I'd have is whether 0.5 on the sub is the same as 0.5 in the receiver. They should be dB, but they might not be, it could be any arbitrary scale. It's probably worth re-running the auto EQ and checking that it sets the sub leve in the receiver to -6. If it does then you can bump it by 2 to get it to a level you're happy with.

Bumping the sub after an auto-eq is common and it registered at -9.5, which is low, but it identified it (if it was -10 you have no idea if it's -10.5 or -20, if that makes sense).

If it sounds good then great. Nothing you've done sounds odd and the next steps all require investment, I wouldn't worry about that yet. Enjoy your system!
 
Thanks! I guess what was making me nervous was Yamaha’s description of subwoofer trim seems different than an overall adjustment of the subwoofer level in the AVR. I am assuming that if I add 6db to the subwoofer level in the AVR, I could take 6db in the subwoofer trim and it would level out. Does that seem right?
 
This is what Yamaha’s marketing says about their subwoofer trim:
The Subwoofer Trim Control enhances the low frequencies by avoiding overlap with the front speaker output. This will result in a cleaner, more focused sound stage while providing a seamless frequency response. When subwoofer frequency overlap occurs in conventional systems, the overall sound is “pushed” toward the subwoofer. Subwoofer Trim Control takes care of this by separating the low subwoofer frequencies cleanly, thus stabilizing the front stage while providing a well-balanced enhanced bass sound. [emphasis added]

Seems like marketing jive to me but if not, it may be another factor to consider.
 

Conrad.

Well-known Member
Odd. Looking at the manual you have both a level (-10 to +10) and a sub trim (-6 to +6).
The trim might be per input, but the manual isn't clear. One's in the options menu and one's in the speaker settings menu 🤷‍♂️

That marketing info seems confused as well. Overlap between frequencies is usually a crossover thing, not a level thing. A disproportional high level will cause the sub to play louder which will overpower the mains, but only up to a point.

I don't use a receiver so I'm out of my depth. I know that the steps you followed sound right in terms of level setting. There are some Yamaha owners on here that might be able to help more.
 
Yeah, crossover is set separately as well so I think Yamaha just got a little saucy with their descriptions. The trim setting may very well be per input, though it does stay put after restarts so maybe that’s where I will make my adjustments. Even with -9.5db set for the main sub level, +6db would still keep me in the negative so much less potential for clipping assuming the trim doesn’t do anything else. Thanks all!
 

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