Question How many LFE subwoofer low level connections per AV amp?

D

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Hello all,

I have a Denon AVR-X3600, which has two subwoofer outputs both with level control. I have read that it is fine to connect a Y splitter to each of these, so that I can connect 4 subwoofers. But I thought I should ask Denon first as I do not want to damage the AV amp. Here is their reply:
1606808862054.png


Do you think that they are being deliberately overcautious? Is there anyone out there who has connected multiple subwoofers to a same or similar AV amp with no problems? Or any electronics experts out there who know whether this reply is rubbish or not?

I'd appreciate your help. Thank you.
 
I think the Denon guy is mixing up speaker outputs with sub outputs, his statement is true for a speaker output. All that will happen if you split an RCA out too many ways is the level will drop, you might pick up some hum the cables are not well screened. The 47k part of the spec means even if you were to short out the RCA output about 20microamps would flow which would be so small it would be difficult to measure.

You need to be a bit more careful with high level connections, can do some damage there but RCA is a tiny signal, can't do much damage with it.

The biggest issue with driving more subs than outputs is being able to adjust the timing independently, sub distance. If you pair two subs that are the same distance away you said you liked symmetry so that should be possible.

I don't know if that exact AVR can set the distance separately for it's two outputs.

Equally you might be lucky and find that all subs on the same timing sounds great, I found that with one of the sub layouts I tried.
 
I tend to agree the Denon guy is playing it safe, there's normally no issues splitting a sub signal like this.

The 3600 has Auddssey XT32 which means the 2sub outputs are separate and the auto setup configures them individually.

My Marantz has the same setup on the sun outputs and I had no issue using just one of the outputs to drive 2 subs before I was able to add an extra cable and use both channels.

Wether 4 subs actually sound better is an entirely different matter, it would probably be much easier to get 2 subs sounding good IMO but YMMV
 
Could you not just daisy chain the subs? Its what I do and works a treat.
 
Could you not just daisy chain the subs? Its what I do and works a treat.

Hello,
The subs only have an LFE input, no output for linking.
Do you mean put the splitter at the sub end instead of the amplifier? Would that make any difference?
Thanks.
 
I got into a bit of a pickle trying to manually eq two subs using the AVR EQ (see monolith thread for details) but Audessy is a bit better than YPAO so auto eq might well be good. Would be interesting to see if it picks a different sub distance for front vs back, assuming you organise the subs that way.

I disagree about making 4 sound good, from what I've seen so far provided the sub amp levels are set up properly then it should be automatically smoother and fewer peaks even without any EQ.

I had enough work travel time last year to read Floyd Toole's book several times and try out the classic sub positions he advocates, only in pairs but in REW I was able to combine different pairs of measurements and see exactly the effects he describes. So far the REW simulator matches my measurements in our room so I'm confident in the results.

This sort of approach:


And/or


You can simulate the ideal 4 sub 1/4 placement with 8 subs placed at the sides of the room, 1/4 and 3/4 on each wall, a bit more practical than 4 in the way to trip over.

Of course ideally they should be 1/4 up in the air and another at 3/4 room height, now we are at 16 subs!

8subs.png


More sensibly if the length node is the biggest problem

4subsLengthNode.png


And if the width node is the problem.

4 subsWidthNode.png


Something to do in these dark winter lockdown evenings ;-)
 

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Hello,
The subs only have an LFE input, no output for linking.
Do you mean put the splitter at the sub end instead of the amplifier? Would that make any difference?
Thanks.
Doesn't matter which end, the signal doesn't know or care, I had a couple of quakes stacked with a splitter at the subs, worked fine.
 
Hello,
The subs only have an LFE input, no output for linking.

I meant this.

An alternative to Y splitters if you are really concerned about overloading the preouts (which in my experience has never been an issue) would be an active splitter like the ones used in studios. A pricier option would be the miniDSP but it also offers a lot more.
 
Thanks Andre, think I will split at the rear left sub for the rear right, as the twin phone currently in place will then have a spare connection if, e.g., I wish to power amp a rear height in the future.

Regarding the sub placement:
Hello darling, please can I put some massive black boxes in our lounge?
No.
They're really important to me and I'm sure you will like what they do.
I don't believe you, TV sound is ok for me, but go on then.
Thank you darling, they need to go here, here and here.
No they do not. They are going in each corner and they have rope lamps mounted on top of them.
OK thank you darling. Love you.

Was the general gist of the conversations ;o)
 
I've had similar conversations with my wife.

It's one of the reasons I like my current speakers that have active subs in the bottom half of the front floor standers.
 
Thanks Andre, think I will split at the rear left sub for the rear right, as the twin phone currently in place will then have a spare connection if, e.g., I wish to power amp a rear height in the future.

Regarding the sub placement:
Hello darling, please can I put some massive black boxes in our lounge?
No.
They're really important to me and I'm sure you will like what they do.
I don't believe you, TV sound is ok for me, but go on then.
Thank you darling, they need to go here, here and here.
No they do not. They are going in each corner and they have rope lamps mounted on top of them.
OK thank you darling. Love you.

Was the general gist of the conversations ;o)

You will probably (should) get better results feeding the two rears together and the two fronts together but no harm in trying.

I'm lucky, my wife is the Movie nut, I only got into it because of her. I like to tinker with the technology and I enjoy the movies, provided the technical presentation is free of major issues. Otherwise I feel I'm at work and need to go resolve the problem before I can enjoy the movie.

We watched a movie at her folks place a while ago, the frame rate was wrong and after the movie I had no idea what it was about, it was 2 hours about judder. Of course now I sorted out the problems, pre covid they just come to us if they want to watch a movie. Her sister moved and doesn't have a TV, they just come to us, well they did.

The only issue I had was moving the sub she was using as a table, we may have to get a third sub so she has her side table back.

I got some push back about bass traps, especially while I was building them in the garden, she put up with it, "you had better be right"... Recently we moved one of them out to futz with the curtains and she said it sounds horrible in here now, please put it back. She always wants to sit in the cinema room, because it's "nicer to talk in here". Apparently if you get Migraines a blacked out cinema room, with deadened sound is a great place to wait it out too.
 
I've had similar conversations with my wife.

It's one of the reasons I like my current speakers that have active subs in the bottom half of the front floor standers.

Good plan.

Although, if she doesn't know they're built in, maybe a possible excuse to get separate subs too!
 
You will probably (should) get better results feeding the two rears together and the two fronts together but no harm in trying.

I'm lucky, my wife is the Movie nut, I only got into it because of her. I like to tinker with the technology and I enjoy the movies, provided the technical presentation is free of major issues. Otherwise I feel I'm at work and need to go resolve the problem before I can enjoy the movie.

We watched a movie at her folks place a while ago, the frame rate was wrong and after the movie I had no idea what it was about, it was 2 hours about judder. Of course now I sorted out the problems, pre covid they just come to us if they want to watch a movie. Her sister moved and doesn't have a TV, they just come to us, well they did.

The only issue I had was moving the sub she was using as a table, we may have to get a third sub so she has her side table back.

I got some push back about bass traps, especially while I was building them in the garden, she put up with it, "you had better be right"... Recently we moved one of them out to futz with the curtains and she said it sounds horrible in here now, please put it back. She always wants to sit in the cinema room, because it's "nicer to talk in here". Apparently if you get Migraines a blacked out cinema room, with deadened sound is a great place to wait it out too.

Haha... I moan but what actually happened was she was very impressed with the sound. She still claims that she doesn't need it. But, for example, the film called "The Old Guard" in Atmos... she wanted to watch again because she said it sounded so amazing!

And, as I have pointed out, I am sure that an REL Stadium would make the most perfect side table!
 
And, as I have pointed out, I am sure that an REL Stadium would make the most perfect side table!

My HT Buddy in Munich actually had two huge REL's either end of his sofa, his 'n hers subwoofers he called them, perfect height for a drinks table.
 
Our front RELs have 1.5m tall rope lamps on them and the rear RELs have the surround speaker (angled) then a 0.4m rope lamp.
Except now of course, FL sub supports the Christmas tree... and I didn't even re-run Audyssey!
 

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