Sony SAWM40: High + Low level inputs at the same time? (1 Viewer)

[Brett_H]

All,

First, the equipment:

Yamaha RXV-870 (Prologic ONLY) receiver

Sony Sub

Bookshelf speakers serving as left, right and center. (mix of older Infinity and Boston Acoustics)

With that out of the way, I've got a question: would I be able to run the sub using both the speaker level inputs and the line level inputs at the same time, and if so, would it sum all inputs or just use one or the other? I should note that I bought the sub open box and it didn't come with the manual, if anyone has a pointer to a .pdf of the manual, I'd really appreciate it!

Reason for this is that my receiver doesn't have any type of bass management, but it does have a "sub out" that is supposedly crossed over at 200 Hz. I have previously had it hooked up through this input, but I've been less than impressed with the results. It always seemed to be lacking something for movies, although I knew the sub was working fine during 2 channel listening. It finally hit me today: I had some music playing that I *knew* should have some decent bass, but there was none to be found. OOPS, had the receiver in Pro-Logic mode. Turned that off and the sub came to life. It seems that the "sub out" on the receiver only catches the L&R channels.

What I was thinking would be to run the center channels (remember, I'm using two bookshelf speakers, and the receiver actually has two outputs for the center) through the sub using the high level inputs and still leave the "sub out" from the receiver connected to catch the bass for the L&R. This is the only way that I can see to get all of the bass from the front three channels to the sub without buying a new receiver.

Anyone care to comment? I can't try it right now as I don't have enough wire to test with....

Thanks,

-Brett.

 

[Philip Hamm]

Before I got my ICBM I ran my DefTech ProSub 100 in a similar way. I used the receiver's sub pre-out for the LFE and center/rear low bass, set the mains to large, and used the speaker connectors for the main L/R bass redirection. I did this to get at least some bass from DTS (The Millenium I was using didn't have bass management) and DVD-Audio.
Calibrating this set-up was a major pain in the ass, but the results were suprisingly good sounding. What matters is if the SONY can handle using both inputs simultaneously. This is a question for Sony.

 

[Brett_H]

OK, so I've got two opinions so far; one for and one against doing this. Someone looked through the manual for me and notes that it doesn't mention this scenario anywhere.

I just emailed Sony, we'll see how long it takes for a response.

Any more input would be appreciated!

-Brett.

 

[Philip Hamm]

I'm sure the scenario isn't in the manual!!! And calibrating is a major bitch.

1) Set up the front L/R speakers to large and wire them through the sub,

2) Calibrate the sub using the sub's volume control and something like Video Essentials Left Right Sub signals, but make sure you are using the DVD players ANALOG stereo output at this point.

3) Then switch to Dolby Digital and calibrate the volume of the sub tone using the sub pre out volume control on the RECEIVER. DO NOT TOUCH THE SUB VOLUME AT THIS TIME. If the sub has L/R inputs with RCA jacks, get a splitter from Radio Shack.

This is how I did it and it worked GREAT.

Note: You may not be able to use this scenario if both inputs are not configurable enough. In my system I had to have the volume on the sub very low to calibrate with the L/R fronts, and I had to jack the pre-out for the sub WAY up on my receiver, almost to max. However, I was able to balance them and the results were very good, even better than I expected to tell you the truth.

 

[Brett_H]

Philip,

Thanks again for your input. Only one problem with the method you described as it applies to my scenario: notice in the first post I said my poor receiver is ProLogic only. None of that fancy-schmancy DD/DTS stuff for me!

To be honest, I think I've decided to just give it a try when I move next weekend and hope for the best. I got an automated response from the email that I sent to Sony that was nothing more than a marketing message directing me to their web store.

I'm hoping that even if my calibration is off it will be better than what I have now. Like I said, I'm getting essentially NO bass from the center channel, and since this seems to be where the majority of the sound comes from in PL mode, I think it would be worthwhile to try it out.

-Brett.

 

[Philip Hamm]

Brett,

Hey it is simpler than you think.

You have a prologic receiver with the sub hooked through the main L/R speakers right?

It sounds to me like you have your center channel speaker set on "WIDE" mode. "WIDE" in ProLogic-speak means send a "wideband" full range signal to the center. Set your center to "NORMAL" and you should be good to go.

 

[Brett_H]

Philip,

No dice. I've tried normal, wide, and phantom modes for the center, and phantom is the only one that makes things sound different, although at the expense of shutting the center completely off. It was my understanding that the difference between "Normal" and "Wide" was that wide simply blend the signal that would normally be sent only to the center into the L&R a bit. I didn't think it had anything to do with bass management. (Although you know far more than I in this area...) At any rate, normal vs wide seemed to make very little (if any) difference in the amount of bass output from the sub. Switching to phantom (directing all front soundstage info to the L&R) resulted in the sub coming to life; a night an day difference.

Here's the way things are hooked up now:

Yamaha "sub-out" -> RCA input on sub.

Here's what I was thinking of doing:

Yamaha "sub-out" -> RCA input on sub.

*plus*

Center channel(s) speaker leads -> high level input on sub, high level output -> center channels.

(The receiver has two powered outs for center channels, with a "summing" switch for them. I have these now connected to the two Boston Acoustic bookshelf speakers that I'm using for a center channel) The Yamaha's "sub out" wasn't really very well defined in the manual, it simply stated that it was crossed at 200Hz, but without saying which channels the information was coming from. From what I've experienced, I'm thinking it's just from the L&R mains.

Again, I'd love to hear from anyone that's tried a similar setup with this particular sub.

Thanks for the input!

-Brett.

 

[Randy Prue]

I've had several subs. The manuals all said, "Never wire high level and low level at the same time."

 

[Philip Hamm]

I've had several subs. The manuals all said, "Never wire high level and low level at the same time."

Which was why I was surprised when the (excellent) tech support at DefTech said that I could do that with my sub. But I don't think that's needed as long as the center is switched off "Wide" and the speaker level connection is used exclusively.

 

[Brett_H]

Philip,

I read the Yamaha manual again this morning, and of course you were right regarding the center channel settings:

Normal = bass redirected to L&R

Wide = "large" center, full range sent to center

Phantom = center turned off.

I'll have to give it a shot using the speaker level connections. (I have yet to use them, I've been using the line level connection exclusively up to this point.)

Along those lines: is it possible to run a 2nd set of wires from the L&R output of the receiver to the sub, leaving the normal L&R speaker connections untouched (i.e., don't route the L&R high level through the sub, run a 2nd set of dedicated wires to the sub)? This would make sub placement and the hiding of the wires easier. I seem to recall someone stating that the speaker level inputs on the sub are of such a resistance so as to make this possible..

Thanks for all the help!

-Brett.

 

[Brett_H]

Anyone?

 

[Brett_H]

One more time before it gets it's own thread:

: Is it possible to run a 2nd set of wires from the L&R speaker output of the receiver to the sub, leaving the normal L&R speaker connections untouched (i.e., don't route the L&R high level through the sub, run a 2nd set of dedicated wires to the sub)? This would make sub placement and the hiding of the wires easier. I seem to recall someone stating that the speaker level inputs on the sub are of such a resistance so as to make this possible..

Thanks!

-Brett.

 

[Geoff L]

Yes you are correct, the draw from the sub speakers speaker level inputs is not a problem! It draw is so little that the reciver dosn't see it as a second set of speakers.
So yes you can run a second set of speaker wires from the reciver to the Subs high level speaker input with out fear of the reciever shutting down... I belive your Yamaha ProLogic reciver even has a second set of (B) speaker outputs.
You could use these and turn them on and off to see and here the differance.
Just make sure you set the recivers center to NORMAL to direct the low frequency to the front mains. They will go to the A & B speaker mains. You also should have a switch on the back of the receiver for your speaker ohm draw rateing when running dual center and dual mains dealing with what the reciver sees for it speaker ohm loads. Set it accordingly to your (current speakers ohm loads) ignoring the sub even if wired with the mains on A or if the sub is wired to the B switch.
I've done this on my fronts and rears on my Pro-Logic ONLY Yamaha reciver ~{with no problems}~. You will get BASS.

 

[Brett_H]

Guys,

WOO-HOO! I moved into my new apartment this past weekend an I finally had a chance to rearrange my setup. You guys were right, using the speaker level inputs made all the difference!

I ran a 2nd set of wires (16 GA Home Depot stuff) from the front outs to the sub instead of the RCA cable. I can really tell the difference now between "NORMAL" and "WIDE" for the center: "NORMAL" and "PHANTOM" have the same bass level (to my ears) whereas "WIDE" is sorely lacking.

An extra bonus is the fact that I'm now on the 1st floor with nothing under me but concrete! No complaints from the neighbors so far, and believe, me, I pushed it to levels I never dreamed of doing in my old place. How sweet it is...

Thanks a ton for all your help!

-Brett.