Please help with LFE problem!

[johnuustal]

I can't figure this out!

I have an NHT Controller and NHT XD speakers. I use the 7.1 analog inputs into the controller. Everything works great except I cant get the LFE channel to play. I have used the channel check on my blu-ray player and also the DOLBY TRUEHD channel check on the Dolby TRUEHD demo disc. All channels play fine except the LFE channel does not play at all. I used the NHT speaker wizard, checked to make sure the settings in the controller are checked “no sub”, I made sure to set the 7.1 analog inputs to all large. The controller should be redirecting the LFE channel to the front left and right speakers but instead when the LFE channel plays during the channel check: silence.

I cant figure out any settings that could be causing the problem. I even took the right main channel and instead of hooking that cable to the right main output on the controller , hooked it to the subwoofer output. Then I get the LFE channel playing through the right main full range speaker (but I lose the right main channel, of course). When i put the wiring back properly, so there is no cable in the subwoofer output of the controller, I cant get any LFE.

PLEASE HELP. Thx!

 

[AVRat]

You need to make sure you're getting an LFE signal out of the BD player analog output so the Controller has a signal to work with. Subwoofer should be set to "Yes" and all speakers set to large in the BD player's speakers setup menu. Which BD player are you using?

 

[Tomorrow]

AVRat has some good suggestions. You might also want to look at this thread for possible answers to your situation.
http://forums.audioholics.com/forums/showthread.php?t=50480

 

[johnuustal]

Thanks!

i am using the Sony S-550, and I checked to make sure the player has the subwoofer set to on and the speakers set to large.

to make extra sure there was LFE output, i hooked up a sub directly to that sub output from the player and got a signal when the LFE played.

 

[Tomorrow]

As happened in the other thread, you are probably getting a signal to the sub...just not strongly enough to trip the auto-on switch or loudly enough to be heard.

I haven't seen this mentioned anywhere, but I think there is definitely a signal drop that affects the output of a sub when a subwoofer analog connection is made from a DVD/BD player -> receiver -> sub.

Can anyone confirm this?

 

[johnuustal]

Nice! That is the first idea that would explain everything. The signal drop could be exacerabted when the controller reroutes the LFE to the Left/Right mains. I wonder if I could confirm it by putting the volume way up and playing an LFE channel check.

 

[Tomorrow]

Nice! That is the first idea that would explain everything. The signal drop could be exacerabted when the controller reroutes the LFE to the Left/Right mains. I wonder if I could confirm it by putting the volume way up and playing an LFE channel check.

I think you'll find that it works and sort of proves the theory. You can also drop the cdp signal strength to the speakers relative to that going to the sub. That way you may not have to crank it volume WAY up. But I was hoping someone would check the actual electrical output of the cdp pre-out vs. the receiver pre-out to the sub(s). I don't have the equipment.

 

[AVRat]

Are you or are you not using a sub with the Xds? I thought not according to your initial post. They really do need to be supplemented with a sub.

The signal drop could be exacerbated when the controller reroutes the LFE to the Left/Right mains.

This is probably the issue and has been mentioned in other threads. I did this test awhile back and the LFE signal sounded fairly crappy and with decreased output on my mains.

Looking at the measured FR of the XdS only, it doesn't look like it'd produce much, if any, of the LFE signal (<120 Hz) anyway. http://www.soundstagemagazine.com/measurements/speakers/nht_xd/

 

[MatthewB.]

The problem your having is common and you arent getting proper bass management from the Bluray player to the reciever. Leave the settings on the reciever alone and go into the setup menu on the Bluray player and select speaker settings in the Bluray menu and adjust the bass to it's highest possible level (+10) this will send the signal to the reciever. Now in the reciever increase your sub level up about +3 or +4 and you should get proper bass from your Bluray player. Only problem is that your other gear (Sat/Cable, gamesystem, or anything else, might be a tad bass heavy and you have to decide if you can live with that, or just make manual adjustements everytime you pop in a Bluray movie. I suggested my settings because those work best for both Bluray and Sat.

Or you can upgrade to a reciever that has HDMI inputs and this will allow the reciver to handle bass management and it doenst matter if you use PCM or Bitstream at that point.

 

[johnuustal]

Thanks for the great advice! I will test all this tonight.

AVRat, I am using 4 XDWs as subs, but none of them are connected ot the subwoofer-out on the controller because they are connected to the XDA amp/crossovers, so according to the controller i have all large speakers and no subs.

 

[AVRat]

Ok that helps, but not so much with your problem. It definitely seems to be an issue with the analog connection. Is this a new issue your having because you're adding BD to the mix? Have you been watching SD material via digital connection without any bass management issues? Does your controller have the HDMI 1.1 connections that I'm seeing in the current manual? If so, I'd let the BD player decode the audio and send it PCM to the controller via HDMI.

 

[johnuustal]

I tested it with the LFE way up compared too the other channels, and blasting it, and still not a thing from the XDW subwoofers when the LFE channel check plays. The LFE level may be a problem, but its not my main problem.

I again checked what happens if I run the sub out from the controller to a sub (i have to do it to the XDA crossover/amp and then to the XDW sub), and the LFE is there. So it wouldnt be a problem if I had a dedicated sub, but the way the NHT XD system works, the subs are connected to the left and right channel. That's why the LFE is supposed to be routed to the left/right mains and play through theXDW subs connected to the left and right main channels.

What do you guys think about taking a y cable from the subwoofer-out on the reciever (so i split the subwoofer signal) and then another y cable at each of the left and right channels (so that i plug one of the subwoofer signals plus the right channel into the right channel xds/xdw and the other subwoofer signal plus the left channel into the left channel speaker xds/xdw), so that i manuually combine the LFE signal with the left channel and also the right channel?

AVRat, yes its an issue that come sup because I'm using the analog connection now that I have the Sony S-550 which sends Dolby TRUEHD through the analog connections. Its the only way for me to get TRUE HD. If I use the 1.1 HDMI, I only get 2 channel PCM (even though its 1.1, it doesnt carry 5.1 channels).

Anything else you coudl think of? It just seems impossible -- the LFE is going to the controller and coming out the subwoofer output ont he controller, yet the LFE refuses to get combined with the left/right channels in the controller OR in the player. How could that be? ic ant figure it out.

 

[johnuustal]

Kal Rubinson appears to have figured out the puzzle:

"Redirecting bass and redirecting LFE are two different things. Many processors/players will not redirect LFE at all as a protective mechanism."

This appears to be the case with NHT Controller for the multi channel analog (but not for the HDMI; with HDMI the LFE will get redirected to the left/right mains along with the bass from any smaller speakers).

Thanks for all the help!

Any advice on the question: I already have 4 powered subwoofers, its just that the NHT XD speaker system pairs a sub with a satellite and treats it as a single (almost) full range speaker. So the question is, am I better off with another (single) sub for the LFE channel, or am I better off using a mixer to send the LFE to the 2 subs connected to the left/right main speakers, or maybe even using a mixer or mixers to send the LFE to all channels with a sub so that all 4 subs play the LFE?

 

[AVRat]

Ok John, I found the note in the manual about 2-channel PCM only over the HDMI (that sux!).

Regarding the question of a dedicated sub: how do you feel the system performs now? You should still get good LF output without the LFE channel. Is it providing the visceral impact that you expect? Is so, then the LFE dedicated sub probably isn’t warranted. You may still want to get the LFE routed to all four subs before you make that decision. I see no problem using Y-adapters (I count 7), since they’re inexpensive, to split the LFE and combine with the other four channels.

One thing I noticed about the XdW’s FR from the link I posted is that the response drops off fairly quickly below 25 Hz. If you want good subsonic bass then a good LFE sub (or 2 depending on room size) is needed.

BTW, don't you sleep?

 

[johnuustal]

Yes I sleep, I love to sleep, but this was driving me crazy! i cant tell you how much I appreciate your help.

I have been able to use an ICBM Bass Management to play the LFE through 2 subs, and it sounds good. But yes, I do want good subsonic bass! i thought that 4 XDWs might do it, but in reality maybe this whole problem was a good thing. If I get a good sub with an 18 inch driver just for the LFE, and use the NHT sat/subs as full range speakers (as they were intended), that sounds conceptually like a great system.

 

[AVRat]

Good to hear that you have an ICBM. That was the first thing that came to mind. An SVS PB13-Ultra, Epik Conquest/Tower/Castle, AV123 MFW-15, or HSU ULS-15 should work nicely.

The NHT Xd system is nice, BUT it definitely has its limitations.