Question on proper bass management settings using a Yamaha RX-V659--Dilemma

[FLMike]

I am doing some upgrading of my system and have been reading up on speaker placement and bass management.

I Read this article here:

The Marriage Between the Subwoofer and Tower Speakers

Lots of good info. It says to set all of your speakers to small, and then set an appropriate crossover. (the mains FR is (+/- 3dB) 45-20,000 Hz -- (+/- 6dB) 35-22,000 Hz) ). So for sake of argument, let's set all speaker to small, set the crossover on the receiver at 60 Hz, and defeat the subwoofer's crossover. My system supports this and by my reading, this would be the correct setting or at least a good starting point to tune from.

That is until I get to this nugget regarding my receiver:
RX-V659 System Setup & Configuration

"In the great tradition of excellent bass management, Yamaha offers a variable crossover point from 40Hz to 200 Hz and also allows subwoofer output in 2CH mode if the speakers are set to LARGE via the LFE/Bass Out set to "Both"."

If I adopt this setting and if I am understanding correctly, I am now using the receivers filter to not send anything below 60Hz to any speaker listed as small, and am outputting all LFE info to both the mains+the sub.

So to prevent overemphasis of bass and to properly mate the sub with the mains I would need to engage the subs Crossover to handle signals below a certain point. This would put the bass signal through two filters, one at the receiver level and one at the Sub. According to the article on bass management this is a real no-no. It says this can result in:

1. Too much transition band attenuation, excessively attenuated signal.
2. Added group delay of two filters cascaded causing phasing problems between subwoofer and main speakers. The result is unwanted canceling of certain bass frequencies.
3. Null or resonance caused by impedance change resulting in accentuation or attenuation of particular frequencies within the passband of the subwoofer

This feels like a real catch-22. So the first question is am I understanding/approaching this correctly overall. Second, am I stuck with not having sub output in 2 channel listening without putting the signal through two filters and is the two filter issue that big a deal (I can see why it would be)? Is there an alternative I am missing?

Thanks for your input.

Mike

 

[Grador]

First, it would help if you posted what speakers you were using and sub.

Since you are using your receiver for bass management the subwoofers low pass filter should not be used at all. This can be achieved in two different ways [depending upon the sub]: either disabled/bypassed, or setting the crossover to the highest possible point thereby moving it out of the way.

If you set any speaker to small then they will not receive any bass below the set crossover point.

The best laid plans can fall flat on their face here given room characteristics. For bass management I always suggest starting at a good guess and then playing around with settings till you feel that the sub and speakers integrate well.

 

[Steve81]

Lots of good info. It says to set all of your speakers to small, and then set an appropriate crossover. (the mains FR is (+/- 3dB) 45-20,000 Hz -- (+/- 6dB) 35-22,000 Hz) ). So for sake of argument, let's set all speaker to small, set the crossover on the receiver at 60 Hz, and defeat the subwoofer's crossover. My system supports this and by my reading, this would be the correct setting or at least a good starting point to tune from.

Yes, that would be a fine starting point.

Second, am I stuck with not having sub output in 2 channel listening without putting the signal through two filters and is the two filter issue that big a deal (I can see why it would be)? Is there an alternative I am missing?

I think you might be misunderstanding (or I am misjudging your intent); if you set your mains to small with a crossover of 60Hz as outlined above, you'll still have subwoofer output in stereo as long as you're not picking Yamaha's equivalent of "pure direct" where it effectively disables all of the receiver's DSP. You don't have to set your mains to large and futz around with multiple filters to accomplish this.

 

[FLMike]

Sorry, got distracted as I was finishing the post. Speakers are Aperion Verus Grands, Sub is an Outlaw LFM-1+. The Center will be either the Verus Forte or Verus Grand. Auditioning both.

Thanks,

Mike

 

[FLMike]

Steve, I may be misunderstanding and will test later. But this is the sentence from the article on the receiver that led me down that path: "allows subwoofer output in 2CH mode if the speakers are set to LARGE via the LFE/Bass Out set to "Both"." It seems to imply that you only get Subwoofer output in two channel mode if speakers are set to large. And I get that pure direct defeats the Sub (love it sometimes).

thanks for the reply.

Mike

 

[Grador]

So if you go for the verus forte, it's rated at -3db at 72 hz, so a good starting point for a crossover would be around 90. This is a tradeoff here...

At 90 you run the risk of having the subwoofer being easily localized (being able to hear where it is), and you may find that the towers [which are capable of going lower] could provide more detailed bass than the sub (never heard the outlaw or the towers, so don't know).

If you go lower you're going to be asking a lot of the center. If you like to listen loud you could run into distortion issues by bottoming out the drivers.

The grand center is speced at 50hz which would give you more leeway on the crossover.

 

[Grador]

Steve, I may be misunderstanding and will test later. But this is the sentence from the article on the receiver that led me down that path: "allows subwoofer output in 2CH mode if the speakers are set to LARGE via the LFE/Bass Out set to "Both"." It seems to imply that you only get Subwoofer output in two channel mode if speakers are set to large. And I get that pure direct defeats the Sub (love it sometimes).

thanks for the reply.

Mike

Two channel mode is useless. If you run it in "strait" the bass management of the receiver will still be used and the signal won't be modified by any of the ridiculous DSPs.

EDIT: you're receiver is older than I thought, researching...

 

[Steve81]

It seems to imply that you only get Subwoofer output in two channel mode if speakers are set to large.

Nah; the idea behind that statement is that if the main speakers are set to large, you're not supposed to get subwoofer output in 2 ch mode as there is nothing to redirect to it. By setting the double-bass mode, you can bypass that. That only applies to setting the speakers to large, which isn't recommended.

 

[Grador]

Ok 2 ch mode DOWNMIXES everything to 2 channel. If you use "standard" any 2 channel sources will play, completely unmolested by DSP, but bass management will still be used.

You would have to jump through those hoops to use subwoofer in 2ch mode, but you don't want to use 2ch mode.

 

[FLMike]

Grador, I get the trade-off which is why I have one of each of them headed my way. I want to pair the Grand Mains with the Grand Center.The problem is that the Grand Center is BIG. I'm not sure that I am going to be able to come up with a workable placement for it.

And I think I get it on 2-channel. You are saying if I run Standard and it's a 2 channel source, then all is good and bass mgmt applies, and it will play 2-channel. But if it's a multi channel source, run in two channel mode it blends everything into two channels which is where this whole large speaker hoops ridiculousness comes in. Thank you for clarifying this.

Regards,

Mike

 

[Steve81]

But if it's a multi channel source, run in two channel mode it blends everything into two channels which is where this whole large speaker hoops ridiculousness comes in.

I'd still wager that's not the case (that is to say downmixing 5.1 to stereo in and of itself shouldn't defeat bass management), but when you get everything in, it doesn't take long to test & verify.

 

[Grador]

Grador, I get the trade-off which is why I have one of each of them headed my way. I want to pair the Grand Mains with the Grand Center.The problem is that the Grand Center is BIG. I'm not sure that I am going to be able to come up with a workable placement for it.

Yeah I've run into the same problem with my setup. You'll see in my sig that I'm running a paradigm center with some EMP towers. If you think the grand verus center is large check out the center that matches my towers....

More what I meant on the tradeoffs though was going higher or lower than 90 with the forte center. No one can really tell you what to set it as because in your specific setup the tradeoffs may sound worse on the higher end of crossover points, or possibly on the lower. You're just going to have to play around with it.

 

[Grador]

On a side note: I've never quite figured out what EXACTlY yamaha does with bass management [their settings are poorly labeled] but I find that unless you set the LFE/BASS to BOTH the subwoofer is under utilized for music sources (with speakers set to small). This setting would make sense to me of the sub was NOT utilized, but it's just under utilized...

 

[FLMike]

Grador, yep I know there is no substitute for trial and error. I knew the settings for the center were going to be a potential trade off going into this. At least the receiver provides a good deal of flexibility and the ability make changes very quickly without interrupting source material. I am going to work with the Forte first (Mains and center arrive Tuesday). The Grand center shipped today and will arrive next Friday. So I will have the following weekend to really play around with both setups. I am **hoping** that I can make the larger center work. But the good news in talking to the guys at Aperion is that the Timbre of the two centers should be very similar. One of theguys is playing with running a grand center with Forte mains in his home rig at the moment. Thanks again for the assist. I like getting these details ironed out before I start something like this so I can get straight to the fun part....Listening!