Loss of Bass Frequencies with Sony STR-DE845 (1 Viewer)

[Malcolm R]

Hi all. This is somewhat related to a post I made in the Speakers/Subwoofers forum last week, but I now think it's a receiver problem so will expand on it here.

The Problem: While listening to CD music, everything starts out OK. But after 3-4 songs, all the bass seems to disappear from the sound. The subwoofer goes silent, there is no bass coming from the fronts. The music retains the same volume, but has lost all the low range. The LFE/bass is also largely missing from digital sources such as DVD. The LFE indicator on the display is scaling the heights, but little if any bass is coming through the sub or the fronts.

This seems to come and go, somewhat, as I was watching "xXx" the last night and while many scenes seemed kind of bass-light, the avalance scene and a couple other explosions still had a pretty good rumble from the sub and fronts. I started watching "Band of Brothers" the other night, which many have said is a very dynamic soundtrack, but there was little if any bass coming through my system despite the LFE levels bouncing all around on the display.

Possible Cause: I'm not sure if this is related at all, but the problems I've been having started after this event, so it very well may be related.

As I was dozing late one night (after some surfing HTF and listening to CD's), there was a brief power interruption. The music had stopped, but the receiver and sub were still on (I think, I'm not 100% sure). However, the power interruption reset all the equipment and rebooted my computer, waking me up. :b

Could this interruption have caused a surge of some sort that fried my bass/LFE circuits so they flutter in and out? I checked all my settings and levels on the receiver and they seem to be where I had them before this problem started.

Anyone have any insights into what may have happened? Are there any other possible explanations? The equipment has not been moved recently, so I don't think there are any loose connections. I have been somewhat concerned with heat buildup as it's setting in a semi-enclosed cabinet, but I've never had issues until the past week and it doesn't seem to get that hot inside the shelves.

I do want to upgrade in the future, but it's a fairly new receiver (2-3 years) and it serves my needs for the moment so I'd rather not be forced into it if it could be a minor issue.

Thanks!

 

[Craig_Kg]

Have you tested the sub? Try just giving it a full line signal from a source like a CD player (make sure you start with the sub volume right down) and see if the sub isn't the cause of the bass dropping out.

 

[Malcolm R]

Hi Craig. I'm something of a hardware virgin, so I'm not sure what you mean. I have tested the whole system using the test tones and the sub (Yamaha SW-205) does seem to be active during the test.

This is so frustrating to me because it seems so random. The source plays fine for a while, then suddenly the bass is gone.

I'm again leaning toward it being a sub issue as usually if I reset the sub (power off at the master switch, then bring it back on) the bass comes back. But as mentioned, when I test with tones, the sub is active. So why does it play the tone but not the source?

Also, I tried setting the receiver as if there were no sub (sub to "no," fronts to "large") and it seemed ok like that, but without the deep bass that's usually added by the sub.

I don't know. I may have fried the sub in some way so that it only plays for a certain amount of time before becoming overloaded and cutting out (though I still don't understand why it would play at all if damaged). The manual and Yamaha website are of no help whatsoever about troubleshooting. :frowning:

Sigh. I guess I'll just have to live with it until I can upgrade to a real sub.

 

[Craig_Kg]

OK, try this.
1. Connect the sub to the receiver by one of the tape out sockets instead of a sub out socket.
2. Make sure the sub is turned way down and then start playing some music.
3. Turn up the sub until you can hear it playing
4. Check for the sub dropping out

Your experience with turning the sub on and off points to the auto power on signal detection being faulty. Can it be disabled? Often there is a switch for this. Then you will have to remember to turn the sub on and off when you use the system but it should work then.

 

[Malcolm R]

Yep, it sounds like that but I've never used the auto on/off feature; I always turn the sub on/off manually and the switch is set as such.

Story: My first receiver required a powered center channel speaker and it only had auto on/off. I got so sick of it cutting out 3-4 times per movie (then coming back on with a loud *POP*) that I swore I'd never use auto on/off again on anything if it could be avoided.

Very odd.

 

[Bob McLaughlin]

Five years later...
Malcolm, I am having the IDENTICAL problem now, so I'm pretty sure it's the receiver. I think it's time for a new receiver anyway, but I am curious if you ever got yours working again?

 

[Malcolm R]

Nope, never got it fixed. Still dealing with it (hoping to upgrade soon), though I'm now pretty sure it's a subwoofer issue. The odd thing is that when the sub cuts out, the sub isn't actually turning off (the power light on my sub goes from green to red when the unit actually turns off). The sub's power light remains green, but the sub just stops functioning, so it doesn't seem to be related to the auto on/off or the power light would change to red when the sub cuts out.

I find that if I flip the main power switch on the rear of the sub off-and-on quickly, the sub comes back to life. Generally it is then fine for the duration, though sometimes it quits again and I have to hit the switch a second time.

Oddly enough, I started using the auto on/off feature on the sub, and it now seems to work fine for movies, but will cut out after about 4-5 minutes when I play music. I generally have to "trick" the sub once or twice when playing CD's before the sub will run normally.

Very strange.

 

[Bob McLaughlin]

Same thing happens with mine. The green light will stay on even though the sub is not putting out any sound. Minutes later, it will be working again. I have also tried the on/off trick and that works some of the time.

What kind of sub do you have? I have an SVS 20-39 PCi.

The reason I think it's the receiver and not the sub, is that I also have a Buttkicker hooked up to the sub output, and it suffers the same problem. Sometimes nothing happens even though the LFE indicator is showing a signal is being sent.

I found some interesting information regarding bad solder joints on Sony receivers. There is even a step-by-step process on the Pechorin's audio and video equipment discussion forum for fixing defective soldering points on the relay pins. It seems to have helped this guy:
str-de845 a/b speaker switch problems - Agoraquest - Sony Forum, News, Reviews

The site he refers to can be found at:

Re[2]: Sony STR SE501 receiver problem

 

[Malcolm R]

Thanks for the info. Though I'm a bit puzzled why, if it was a problem with the receiver (such as the solder joints), that flipping the power main on the sub would "reactivate" the output from the receiver?

I have a Yamaha sub (...at work and can't recall the model right now).




.

 

[Bob McLaughlin]

I see what you're saying, it doesn't make sense that it would be a receiver issue if turning the sub on/off would make a difference. Unless turning on the power causes some sort of surge or drain at the receiver? The one thing about the bad solder theory is that it makes sense that it would be inconsistent as the solder joint would expand as the receiver heated up, resulting in inconsistency of contact.

It is an odd coincidence that we have the same receiver but different subs yet the same problem. If you have a second subwoofer, even a cheap one, that might help us diagnose this issue. I don't have a second subwoofer to try; maybe I'll hook up an old regular speaker to the sub port and see if it reacts in the same way (I'll have to temporarily change the crossover).

BTW, I get the same problem regardless which of the two sub ports on the receiver I use, have you tried both?

 

[Malcolm R]

I don't have a second sub, and I don't believe I've ever tried the other sub port (I'm not even sure I knew there were two )

 

[Bob McLaughlin]

Believe it or not, you can get the light on your sub to turn green even if nothing is hooked up at the other end. If you take the input cord from the sub and just touch the RCA end with your finger (while the sub power is on) you'll hear a noise (keep the volume down so you don't blow out your sub speaker!) So I think when you turn your sub on/off it's just getting the sub's detection circuitry to notice that there is something hooked up at the other end. Later the sub goes back to sleep when it is not "hearing" anything coming from the receiver.