Home Theater catch-all

Haha!

On a different subject, I've had trouble with my DefTech sub pretty much since I got it. That was somewhere around 15 years ago. It likes to give off a hum. Sometimes it is real soft, sometimes it isn't. Sometimes, just touching the Level knob was enough to make it stop or diminish, and sometimes that wouldn't help. This has happened in all 3 houses that I've lived in since I bought it. I recently moved the Amp downstairs as I mentioned earlier and tested it. It didn't take long before it started happening.

I figure it could be a grounding issue, a cable issue, a "you connected it wrong" issue, an interference from something else issue, or just about anything else.

So, before trying to diagnose it, I'd like to know what the correct way is to hook this sub up to my particular amp. Ill put a pic of the back of the amp and the back of the sub below. I'll hook it up that way and then go from there.

The Denon AVR-3806 amp is 7.2 with multiple zones. For this situation, assume 5.1.

Amp:
IMAGE(https://i.imgur.com/k0w7vN0.jpg)

Sub:
IMAGE(https://i.imgur.com/E8O9bNm.jpg)

-BEP

I haven't seen a receiver with this particular arrangement of inputs and outputs, where there is no obvious lfe output, but I believe you should be connecting the pre-out labeled SW to the lfe input on the sub.

However you can also put it in the speaker wire path by connecting the amp's speaker outputs to the sub's high level inputs, and then the sub's high level outputs to the front left and right speakers. If you do the latter you just need to make sure your amp's front speaker settings are set to large and if possible disable the lfe output so that it doesn't filter out lfe from the front speakers.

If the hum is produced in both connection scenarios, the sub is likely the issue. If it only occurs in one of the scenarios, the amp is likely the issue.

Yeah, I had to puzzle at it for a bit, but I'm pretty sure you should run a cable from "SW" in the Pre-Out section to the yellow LFE port on the bottom of the sub.

Don't get confused with the SW in of the Ext In section. You want the second SW port, sixth down from the top, fifth up from the bottom, in the second column of red RCA ports.

If it's still humming after that, the sub's amplifier might be at fault.

You could also try the speaker-wire version, but that's intended for amplified sound sources that can't do bass management. The 3806 can definitely do bass management.

Malor wrote:

Yeah, I had to puzzle at it for a bit, but I'm pretty sure you should run a cable from "SW" in the Pre-Out section to the yellow LFE port on the bottom of the sub.

This should be correct, though I cannot ever remember seeing a home theater receiver that leaves the SW output in a separate pre-out section. That's very weird. My very first 5.1 receiver had pre-outs, but also had a dedicated LFE output. That was... yeesh, 20 years ago?

bepnewt wrote:

I figure it could be a grounding issue, a cable issue, a "you connected it wrong" issue, an interference from something else issue, or just about anything else.

A hum like you're describing is typically some kind of ground loop issue, just as you thought. Can be maddening to trace out though.

I'd try Mao's suggestion first if you have the speaker wire for it. Run your front speaker connections to the sub, and then from there to the front speakers, and set the fronts to full range. Then adjust the manual crossover setting on the sub to filter out what gets sent to your front speakers. 80hz is kind of a standard recommendation, but 100hz might be necessary if you're using particularly small satellite speakers as fronts.

I wouldn't do the speaker-wire setup on any kind of permanent basis, because it's inferior to proper bass management by the receiver. Instead of getting all the bass from all the channels, you're getting only the bass from the front L+R. This can still mostly work, and if it fixes the hum I guess it might be worth it, but doing it properly will usually give better results.

Normally, just getting the speaker and sub onto the same outlet will fix a ground loop.

Some amps have a hum to them, no matter what, and that might be what's happening here. It's usually a sign of poor design or cheap construction. I thought DefTech was a high quality outfit, but maybe not?

Not meant as a final solution, just a quick-ish way of testing if it's the Sub's amp on it's own or something in the signal path.

Also: It's possible Definitive Technologies is a perfectly fine sub maker and he just got a lemon with a minor amp issue.

Stuff happens.

I had an amp die in one of my SVS subs. It was roughly six months out of warranty as I recall. They were mystified. I contacted them to ask them if I could order just the amp directly and what it would cost. Instead they shipped me a new amp for free anyway.

If you end up looking for a replacement, all the recommendations for SVS from me.

I did some reading on subwoofers in general and my Denon amp specifically. Now, I understand when to use LFE (or LFE + Main), what to set my speakers to in the amp (large vs. small) for specific situations, and more stuff about subwoofers than I will be able to retain until tomorrow.

After reading, I messed around with the setup. I plugged the sub in and after about 3 seconds, it started the hum. It wasn't loud, but it was there - we'll call this level 2. We have an open floor plan with the living room abutting the kitchen. I went into the kitchen and could barely hear it. Barely, and only because I knew what to listen for.

Then I plugged in the RCA to the sub. One end was in the SW out on the Denon and the other was now in the LFE on the sub. The second the RCA jack came in contact with the RCA connector on the sub, the humming doubled in volume - we'll call this level 4 - and it stayed at level 4 while plugged in. Unplug it - goes back to the lower level 2 volume hum. Back in, it doubles back to 4.

Playing TV or music didn't change anything, it still hummed along while it did it's normal sub thing.

I unplugged the RCA cable then unplugged the sub from power. Then plugged it back in and it started the level 2 hum. THEN, without connecting the sub I touched one of the screws on the sub and it went to level 4. Stop touching - level 2. Touch the back plate - level 4, stop touching - level 2.

So far, when the sub was plugged into a recep, it was a different one than the receiver. The receiver is plugged directly into the wall on a different recep. I then plugged the power cord from the sub into a power strip that is plugged into the second outlet on the same recep that the receiver is in.

This made no difference. I was really hoping that it was a ground loop issue and this would fix it. I got out my recep tester to make sure that the polarity wasn't messed up on the receps and they were all fine. What I didn't do is plug both the receive and the sub into the power strip. I should have tried that.

While the sub was sitting there not connected to the Denon, merrily humming along at level 2, I turned the dial on the sub's Low Pass Crossover. It was sitting around 90hz before I touched it. I did not expect anything to happen but was surprised. When I turned it down to the lowest setting, 40hz, the hum didn't get louder or softer, but there were some soft, audible pops when I turned it. Then, I turned it all the way up to 150hz and the hum got softer. About half as loud as level 2 (which I'll call level 1). I turned it back down, and it went back to level 2. Turned it back up, and the volume went down to level 1 again. At this point, the hum was barely perceptible. In the Kitchen, I couldn't hear/feel it.

While the crossover was sitting at 150hz and the volume of the hum at 0.5, I touched the back plate and it went up to level 2. Stop touching it, back to level 1.

It would take some effort to go the other route and run the speakers through the sub using the sub's crossover. I may still try it, but I don't expect any better results.

At this point, the humming is almost acceptable. It would be even more acceptable if I plugged the sub's power cord into the amp and let the amp power the sub on and off. The amp normally runs 24/7, but I could maybe get Kit to turn it off when she's not using it. The idea of turning it off to stop the humming may convince her.

The whole "old amp downstairs" thing was originally just to test the speakers in the ceiling in preparation for the new amp. That is, until 2 days ago when we found out that Kit has to get a tooth implant. And yesterday, when the guy who started the back porch project found evidence of termites. So, it looks like no new amp and the Denon is staying downstairs.

I've been scouring the 'net trying to find any replacement parts for the sub to no avail. Someone who knew what they were doing could buy some other amp for this thing to make it work, but not this guy.

-BEP

That definitely sounds like a problem with the electronics in the sub, since it hums just plugged into the wall. That more or less proves it's not the Denon.

Setting the crossover higher won't hurt anything, because you'll be doing the crossover on the receiver.... if you set it at the typical 80Hz, then the sub will only get those signals, and the higher setting won't change anything. (except reduce the hum.) The sub would go higher, but the receiver won't send it anything over 80.

The fact that touching the back plate increases the hum makes me wonder if it's not an internal grounding problem. You could try opening it and see if any wires are touching the metal case or look obviously wrong or shorted.

The popping when you turn the dial usually means some corrosion in that potentiometer. Getting some electronics cleaner in there and turning it repeatedly should eliminate that. It might take care of the hum as well.

Deoxit or Crc 5103 are the ones I tend to use the most.

Say I want a 4K Blu-ray player but don’t want it to be a PS5 or Xbox. Are there particular good options out there, or ones to at least avoid?

beanman101283 wrote:

Say I want a 4K Blu-ray player but don’t want it to be a PS5 or Xbox. Are there particular good options out there, or ones to at least avoid?

I have a Samsung player that is fine as long as you only play 4k discs in it. The upscaling of regular blu rays is horribly flawed and reddish hues moving on dark or black backgrounds end up smearing and artifacting in extremely distracting ways. It was their top of the line player at the time so to say I've been disappointed is an understatement.

The Sony player I have, the UBP-X700 is *much* better with regular blu ray discs and just as good with 4k. It was also cheaper.

I've read very good things about Panasonic's newer players, but I don't have direct experience with those. Maybe worth a look though.

I had a Sony one for a while and it was fine. I think we bought whatever looked good at Costco at the time but they probably don't sell bluray players in store any longer.

Thanks for the tips. That Sony one runs for around $150 these days, which doesn't seem too bad.

For that price why not just get a console? I’d think hard about paying more than $75 or so for a dedicated Blu-ray player these days.

LeapingGnome wrote:

I had a Sony one for a while and it was fine. I think we bought whatever looked good at Costco at the time but they probably don't sell bluray players in store any longer.

Just saw an LG 4K Blu-Ray player at Costco the other day, us physical media enthusiasts still exist

I am following this closely. My beloved Oppo 93 gave up the farm and I am looking for another player. I have somewhere around 1300 DVD and would like to be able to play them. I am not a console gamer so anything other than a player is wasted money.

Our new house has a loft with built-in speakers already in. They're a nice klipsch that would handle the left and right channels both front and rear. So all I need to do is get an amplifier, center channel, and sub for a 5.1 setup.

I'd like to do it on the cheap, though, cause it's mostly for family movie nights and right outside my kids' rooms.

Any suggestions? I don't know anything about DTS, dolby, etc.

Something is acting up with my audio. I have a suspicion its my receiver... but I'll put it out to the GWJ collective.

I have an older 5.1 receiver, but a new LG 4K TV, a PS5, as well as a Roku Ultra. That 5.1 receiver can't pass a 4K signal, so I have everything going into the TV for picture and then back to the receiver via ARC.

Problem is that every so often (maybe every 5-15 minutes) on a 5.1 signal, the audio cuts out for a second. The indicators on the receiver that show which speakers are active they all "blink". Picture stays on the whole time , literally just audio for a second maybe less, but anything like that is very noticeable.

I've double checked cables, and I don't think that's the issue, but who knows.

Carlbear95 wrote:

Something is acting up with my audio. I have a suspicion its my receiver... but I'll put it out to the GWJ collective.

I have an older 5.1 receiver, but a new LG 4K TV, a PS5, as well as a Roku Ultra. That 5.1 receiver can't pass a 4K signal, so I have everything going into the TV for picture and then back to the receiver via ARC.

Problem is that every so often (maybe every 5-15 minutes) on a 5.1 signal, the audio cuts out for a second. The indicators on the receiver that show which speakers are active they all "blink". Picture stays on the whole time , literally just audio for a second maybe less, but anything like that is very noticeable.

I've double checked cables, and I don't think that's the issue, but who knows.

did you try changing cables? That'd be my first step.

That sounds like the TV is frequently doing an audio signal "sync" where it's testing the receiver for different sound processing formats (DTS, Dolby HD, PCM, etc). Generally, this can be avoided by forcing the TV to output a specific audio format and then making the same change on the receiver so that it knows what type of signal should be incoming.

All the usual disclaimers apply; I have been known to be wrong in the past, and I'm pretty sure I'll be wrong in the future, so I could be totally wrong about this. YMMV.

ThatGuy42 wrote:

That sounds like the TV is frequently doing an audio signal "sync" where it's testing the receiver for different sound processing formats (DTS, Dolby HD, PCM, etc). Generally, this can be avoided by forcing the TV to output a specific audio format and then making the same change on the receiver so that it knows what type of signal should be incoming.

All the usual disclaimers apply; I have been known to be wrong in the past, and I'm pretty sure I'll be wrong in the future, so I could be totally wrong about this. YMMV.

Hmm this could be it, and definitely the behavior checks out. The receiver is set to "Straight" so it takes whatever its given and tries to figure it out. I guess my question then is where do I need to "fix" the signal? Likely answer is the receiver since that should be the best piece of equipment to convert a non-surround signal to 5.1. Is Dolby vs. DTS still a thing? I probably convinced myself I need to keep it on auto sync because god forbid I listen to something originally processed in DTS in Dolby but I doubt I actually know the difference

Reminds me that I hate ARC.

Many TV's downgrade or modify the signal they send over ARC so you'll have to get into the TV settings to see what output signal is supported. But, generally speaking, I find you can get the best sound by just setting everything to DTS. If you can set the TV to pass DTS, and then set the receiver to process DTS, you should be golden. The downside of that setting is if the TV can't process the sound it is presented with, it should downgrade the output to send simple stereo sound, and a receiver in DTS mode will likely just play it stereo as-is. I know there are some surround sound tests on various streaming services like Netflix so you should be able to take an hour or two to play around with those settings until you get something that works well.

TheGameguru wrote:

Reminds me that I hate ARC.

Ditto. It's a great kind of core idea but the implementation is so often terrible I try to avoid it whenever possible.

Looking for recommendations on a 5.1 surround system for my brother's renovated basement TV room. Knowing him he would get frustrated dealing with a regular receiver. Wires in are installed in the walls for the speakers. Hookups would be needed for a Series X and Switch. Are their any go-to all in one setups that would fit the bill?

I'm on record saying you should always buy the best possible receiver you can, and then add speakers as necessary. But, if you want an all-in-one package for entry level 5.1 you can do a lot worse than this Onkyo set at Amazon. That's literally the newer version of the starter package I bought years and years ago.

The Onkyo receiver is not the best, but it's no slouch either. It has all the major check boxes including 4K, HDCP 2.2 and DTS. The speakers in that size will be a little weak, but not overly so for watching TV and playing games. And, you can always upgrade the speakers later.

Is that the sort of suggestion you're looking for, or were you thinking along different lines?

Heh, I'm actually of the exact opposite opinion. In my experience, the thing that really matters in a system is the speakers. Buy great speakers, and drive them with a cheap but competent amp, and you will have a fantastic-sounding setup. Buy great electronics, but hook them up to crap speakers, and the system will sound awful. Speakers matter more than anything else, and they last for decades, so buy something you really like, skimping on the electronics for a year or two if necessary.

If you want a Home Theater In A Box setup, they're not as common as they used to be, and I haven't seen any recent tests or much discussion about what's good. Eight or ten years ago, Onkyo was making really good HTIBs, and one major advantage was that they used all standard components and connectors, so you could swap out any piece you wanted to upgrade it later. (or replace it, if it broke.) Standard connectors will be critical for you, because you want to use the room wiring. Don't buy any HTIB that uses anything proprietary. And don't buy a soundbar, they won't do what you want at all.

The standard way of filling out a system like that is to buy a set of speakers, and then to buy a receiver to drive them. Fluance was well-regarded for having good speakers on the cheap when I was looking, but it's been many years and I'm not current at all. Thin_J is kind of our resident speaker expert, but I don't think he's really gone shopping for about five years, so he may be out of date, too. I think he was last talking about Parts Express as being a surprisingly good source for speakers, maybe? I'm not sure, but I kinda remember him saying good things about their speakers, or at least their speaker components. (maybe it was a DIY kit? Dunno.)

If you do go the classic route, to reiterate, focus most on the speakers. Get a quality set that really works for your ears, and they can last you for a substantial chunk of your life. Don't go overboard on the receiver, those go out of date every few years anyway.

EvilDead wrote:

Looking for recommendations on a 5.1 surround system for my brother's renovated basement TV room. Knowing him he would get frustrated dealing with a regular receiver. Wires in are installed in the walls for the speakers. Hookups would be needed for a Series X and Switch. Are their any go-to all in one setups that would fit the bill?

Is HDMI 2.1 a desire? That would determine a great deal what you put in between the TV and the Series X

ThatGuy42 wrote:

I'm on record saying you should always buy the best possible receiver you can, and then add speakers as necessary. But, if you want an all-in-one package for entry level 5.1 you can do a lot worse than this Onkyo set at Amazon. That's literally the newer version of the starter package I bought years and years ago.

The Onkyo receiver is not the best, but it's no slouch either. It has all the major check boxes including 4K, HDCP 2.2 and DTS. The speakers in that size will be a little weak, but not overly so for watching TV and playing games. And, you can always upgrade the speakers later.

Is that the sort of suggestion you're looking for, or were you thinking along different lines?

That might do. I haven't done my research yet but was thinking there would have been stuff like a soundbar / amp combo that would drive everything.

@Malor - That's more or less how I have my setup now but he isn't the type of person to fuss with parts. He'll just want to set it up and never think about it again.

TheGameguru wrote:

Is HDMI 2.1 a desire? That would determine a great deal what you put in between the TV and the Series X

How so? He just got his TV 1-2 years ago so I will ask him the model.

Edit: TV is https://www.lg.com/us/tvs/lg-49UH610... , Looks like I was off on the 1-2 years old.

3 HDMI (HDCP 2.2) ports.