LFE on Onkyo 805

[griffinconst]

Do I need to tell my receiver that the sub is connected through the LFE?
I ran Audyssey and it recognized the sub. My problem is that my sub works for a while then shuts itself off. I suspected it wasn't getting enough signal to keep the automatic on/off switch on. When I connect it through the speaker wire connection it stays on the whole time. Am I right to think there is something wrong with the LFE on my receiver or do need to turn it on somehow? - Thanks for any help.

 

[Adam]

Hi. When you connect it with speaker wire, there's more power being sent to the sub, so it probably helps trip the auto on sensor. Also, it will extract the frequencies below the crossover setting for all audio being sent to it, so it won't just be the LFE track. That could also help trip the sensor.

When using the line-level connection, you can increase the subwoofer level setting in the receiver (and consequently turn the volume on the sub itself down to compensate) to help trigger the auto on sensor.

Are you running your speakers as full range? If so, then only the LFE track would go to the sub if you use the line-level connection. You might want to run your speakers as small. I can't remember which sub and speakers you have (sorry).

 

[griffinconst]

Thanks for responding so quickly Adam and good to see you're back. Are you a fixture around here or what??? Any chance you're going to the GTG next week? I'd like to meet you in person.
Ok, back to my problem...My 805 doesn't have a large and small setting, if you say your using a sub you must choose a crossover point. I have run it anywhere from 80-40 and it doesn't seem to make any difference with the sub sensor. Does that give you any other ideas I might try?
By the way, I've had a DefTech sub for about 10 years and recently picked up a pair of Athena AS F2 towers for.....wait for it....$115.00 in perfect condition off Craigs list.
I like them pretty well but I wish I would have grabbed those NHT 2.5i's we were talking about a couple months ago.
So, any other thoughts on my LFE troubles?

 

[Adam]

I wish that I could come up there and meet everyone, but I won't be making it next weekend. I sure hope that everyone has a fantastic time.

Are you running a 5.1 system, or something else? I ask because I'm wondering if you set all of your speakers to have a crossover or if some are set to "Full Band" (I accidentally said "full range" above).

Also, did you try increasing the subwoofer output level from the receiver (mentioned above) to see if that would help trigger the subwoofer sensor? That worked for me on my previous subwoofer.

 

[griffinconst]

I think I did try setting the sub level higher but I'll give it another shot. Thanks

 

[sptrout]

FYI - - Becareful: Based on Audyssey's frequency response report to the AVR, the 805 will set any speaker to "large" that has a -3dB point of 80Hz or lower. My 805 will set four of my speakers to "large" (except for two poor ceiling speakers and my center channel speaker) everytime I rerun Audyssey. You always need to go back into the speaker setup screen and make sure that the crossovers are set to almost any thing other than large.

This any thing lower than "80Hz" seems to be very common at least with older AVRs.

 

[lsiberian]

Do I need to tell my receiver that the sub is connected through the LFE?
I ran Audyssey and it recognized the sub. My problem is that my sub works for a while then shuts itself off. I suspected it wasn't getting enough signal to keep the automatic on/off switch on. When I connect it through the speaker wire connection it stays on the whole time. Am I right to think there is something wrong with the LFE on my receiver or do need to turn it on somehow? - Thanks for any help.

As a former owner of those type of amps.

first make sure you hooked up your sub to the pre-out. (i did that wrong once.)

2nd change your crossovers in the manual setup menu from full band to 80hz.
That should get you going.

 

[MatthewB.]

Yes your 805 does have a large and small setting, you have to go into speaker setup and adjust the crossovers for each channel, if you set the crossover to Full band it is automatically set to Large and if you choose a setting above 40Hz it is automatically setting that speaker to small.

When setting Mains to Full band it may engage the "Double Bass" feature and it is up to you if you want to use that feature or manually shut it off. Double Bass just also sends the full range bass signal that your mains are getting also to the sub.

My suggestion is to set your subs crossover to it's highest crossover point (since you'll be using the recievers crossovers and you don't want to use double crossover points.

Set all your speakers to small (inlcuding large towers) if it can be run full range set the 805 to it's lowest crossover point which is 40Hz, if other speakers do not have large woofers or built in subs set the crossover point higher say 80Hz (THX recommended)

I have DefTech 7001s with built in subs and I even set those to small with the 40Hz crossover and the bass sounds very tight and controlled, when set to Full Band (or Large) the bass was bloated, the frequency at the speakers dropped like a rock at 30Hz and I found it better to set to small.

My SVS kicks on everytime

I have my Deftech 7001s set at 40Hz (built in subs with passive radiators)
DefTech LCR2002 attached to outboard powered 10"sub set at 50Hz
Deftech Studio monitors set at 70Hz (they have a passive radiator for bass)
DefTech Mythos Gems set at 150Hz (small 3.5" drivers can't get lower than that)

So as you see each speaker is set to different crossovers and my SVS handles everything, including the center channel which has it's own dedcated sub hooked up. By setting the subs crossover set to 120Hz in the reciever all channels signals below the set crossover point activate the sub. The only frequency I am missing is 120Hz-150Hz in the rear channels because it becomes localized if I set higher.

 

[vkumar]

Matthew,
I have the SVS without the built in amplfier. Currently I am using the sub output from my reciever and connecting it to another receiver and using its amplifier to power the subwoofer.

One of these days I am getting a new reciever. WIll this connection arrangement work with Audyseey or similar? Sorry for the thread hijack.
Vijay

 

[sptrout]

Sorry for hijacking this thread, but this is first time that this subject has come-up recently where I can ask for comments about the two posts below from Blu-ray.com. The discussion in the posts below have interesting comments about setting speaker crossovers. BTW - - Sure to read the whitepaper link that is contained within the post #2.

http://forum.blu-ray.com/showpost.php?p=2093478&postcount=220

http://forum.blu-ray.com/showpost.php?p=2095299&postcount=227

Bottom line from the posts above; it is very important to have all speakers set to the same crossover if at all possible to prevent serious phasing problems. I read several HT Boards and have never read any thing like what is presented in these links, but it sure makes for some interesting reading!

 

[griffinconst]

Thanks for all the great advice. I tried a lot of those things and learned more about my receiver in the process. I still have the sub turning off after 10-20 minutes though.
I did find out a few other things. I get no sub when using the stereo, direct, and pure audio modes, even when the sub is on. I get plenty of sub in all the other modes but only for 10-20 minutes, then the sub shuts itself down. Am I right to think this couldn't be a cable (connection) problem or a problem with the sub's amp, as the sub does function for that 10-20 minutes?
So I'm thinking my LFE circuit has a problem, but why do I never get sub in stereo, direct, and pure modes? Also remember that the sub stays on if wired with speaker wire to one of the front channels and works in stereo mode that way.

 

[sptrout]

Thanks for all the great advice. I tried a lot of those things and learned more about my receiver in the process. I still have the sub turning off after 10-20 minutes though.
I did find out a few other things. I get no sub when using the stereo, direct, and pure audio modes, even when the sub is on. I get plenty of sub in all the other modes but only for 10-20 minutes, then the sub shuts itself down. Am I right to think this couldn't be a cable (connection) problem or a problem with the sub's amp, as the sub does function for that 10-20 minutes?
So I'm thinking my LFE circuit has a problem, but why do I never get sub in stereo, direct, and pure modes? Also remember that the sub stays on if wired with speaker wire to one of the front channels and works in stereo mode that way.

When using Direct & Pure Modes all digital audio processing is turned-off, including Audyssey & bass management. That is the reason most folks (my guess) do not like either mode.

Stereo should work fine (Audyssey & BMS active). The only recent stereo CD that I have listen to is Michael Jackson's Greatest Hits, and believe me the subwoofer was working!

As for your sub problem, does everything work OK if you just turn it on full time? Many folks have written that is what they do to get around issues like yours if they cannot find the actual problem.

 

[griffinconst]

When using Direct & Pure Modes all digital audio processing is turned-off, including Audyssey & bass management. That is the reason most folks (my guess) do not like either mode.

Stereo should work fine (Audyssey & BS active). The only recent stereo CD that I have listen to is Michael Jackson's Greatest Hit, and believe me the subswoofer was working!

As for your sub problem, does everything work OK if you just turn it on full time? Many folks have written that is what they do to get around issues like yours if they cannot find the actual problem.

I don't think I can turn it on full time. There is no external switch and I have it plugged into an unswitched plug. Is there a way to turn it on that I'm missing? I have to unplug and plug it back in to get it to turn on when I first power up and after it shuts down 20 minutes later, it will turn back on if I unplug and plug it back in again...then I get another 20 minutes before it shuts down again.

 

[sptrout]

Most Subs that I know about have a three-way switch; Auto, Off, On (full time). That is what I was referring to. If this type of switch exists on your sub it should be obvious.

 

[jostenmeat]

Sorry for hijacking this thread, but this is first time that this subject has come-up recently where I can ask for comments about the two posts below from Blu-ray.com. The discussion in the posts below have interesting comments about setting speaker crossovers. BTW - - Sure to read the whitepaper link that is contained within the post #2.

http://forum.blu-ray.com/showpost.php?p=2093478&postcount=220

http://forum.blu-ray.com/showpost.php?p=2095299&postcount=227

Bottom line from the posts above; it is very important to have all speakers set to the same crossover if at all possible to prevent serious phasing problems. I read several HT Boards and have never read any thing like what is presented in these links, but it sure makes for some interesting reading!

Hm. I am very far from being any kind of expert on this stuff, but . . .

I wonder why an 8th order xover was used. There's probably something I'm misunderstanding. I think most receivers use only a 2nd order crossover? (and some do 4th order . . .?) That means the out of phase issue is greatly diminished.

Even your own speakers' drivers are out of phase, and the steeper the slope, the more out of phase they are. OTOH, by using something like 1st order xovers for "best phase", you suffer offaxis if I understand correctly.

Another thing, in my opinion, regarding certain speakers as large and others as small creating phase issues: I pretty much never notice all of the speakers playing the exact same thing, at the exact same time.

I think some receivers, maybe very old ones, would output 2nd order to subwoofer, and 1st order to speakers (as they figure that in combination with the natural rolloff of the speaker would be a close approximation of the 2nd order rolloff).

Lastly, I think it might've been Gene talking about it, but some receivers do something pretty funky, in support of using the identical xover point for all speakers if only to avoid very bad implementation. IIRC, let's say you set mains as 40hz, and other speakers as 80hz, the mains would only play 80hz and up, and that 40-80hz info is just completely lost, not reproduced at all anywhere. I say IIRC, because that sounds so funky, I'm second guessing my memory for sure here.

 

[MatthewB.]

Try a different RCA cable and see if that works. To me it sounds like the amp is the problem. For some reason when you use RCA it is having issues but not with speaker wire. So lets' break this down and try a different RCA cable and see if that is the issue. I had an issue years ago with a small staple (used to secure the cable to the wall) that was causing the sub to short out much like your situation, hence why I say try another cable and see if the problem persists. If anopther cable still gives you the same issues, it's the amp. I find it odd that it would work for 20 minutes than shut off, telling me it's more likley an amp issue.

Vjay, yes you can hook up your passive amp this way, but I would highly recommend an outboard mono amp or stereo amp that you can bridge, you'll find you'll have more power on hand than using a spare reciever to drive your sub.

 

[griffinconst]

Thanks Mathew, I'll try it but I have assumed if it was the cable it wouldn't work at all. The sub shutting down after 20 min. makes me think the receiver's LFE isn't sending enough signal to keep the sub's switch sensor on.

 

[strube]

Thanks Mathew, I'll try it but I have assumed if it was the cable it wouldn't work at all. The sub shutting down after 20 min. makes me think the receiver's LFE isn't sending enough signal to keep the sub's switch sensor on.

Okay, I have a weird question:

When you say the sub is on for 10-20 minutes can you actually hear it, or do you just have an LED letting you know it is awake?

I had this issue quite a while ago with a completely different receiver, and could never figure out the problem. My sub would turn on when I had my AVR at obscene levels, or when I turned it on manually, by plugging and unplugging the signal wire. I had to have the gain pretty high to get the bass I was expecting, but if the gain was where it should have been, I would hear nothing. When I did figure it out, I felt kind of silly, but it happens . One day I stumbled across the settings for my individual channel levels on my particular unit (completely separate from the test tone level settings - why? I do not know...), which could not be accessed by any menu function, but instead a "secret " button on the remote, where I found that the sub level was turned down to -26dB. Cranked it back to 0dB where it should have been, and viola, bass (about 26dB too loud, at that )!

Don't know if that will help, but I hope so.