Line level vs volume on SUB

[jaseman]

I have a Panasonic SA-XR55 receiver with LFE out. The receiver can adjust the line level signal from Minimum->5->10->15->Max. This of course affects the volume of the SUB. Then of course there is a volume knob on the SUB itself.

What is the best way to set this up?
Should I set the line level lower and the SUB volume higher, or the other way around? Or, should I try to balance them out so that they are closer to equal?

Thanks in advance for any assistance!

 

[MDS]

min-5-10-15-max is rather odd if that is really the subwoofer channel trim. It sounds to me more like LFE level which should usually be set at zero (it's used to compensate for dvd players or incorrectly mastered discs that boost the LFE level too high).

Now if it is the subwoofer level control then it is for calibrating the level of the sub to the same level as the other channels. You start at the minimum with the sub's volume control about 1/3 of the way up. If the SPL meter reads too low then you either bump up the sub volume or the sub level in the receiver. Generally you don't want to turn up the sub volume past about half way. The two volume settings work hand in hand so it is a bit of trial and error until you get the SPL reading you want.

 

[Adam]

Hey, jaseman. I looked up your owner's manual to get a better idea about this. I just skimmed through it, but I can understand your confusion. While most speaker levels on your receiver are set from -10dB to +10dB (which is the common approach), the subwoofer level is set at either "MIN", a value from 1 to 19, or "MAX". So, in effect, the subwoofer level is set between 0 and 20. I'm assuming that "MIN" (i.e. 0) is the same as -10dB and that "MAX" (i.e. 20) is +10dB. The factory setting for the sub is 10, which corresponds to a level adjustment of 0dB under my assumption, and that makes sense to me.

I would recommend that if you use an auto-power on setting on your sub that you keep the subwoofer level on the receiver set to 10 or above and that then you adjust the volume knob on the subwoofer to get the appropriate volume. I recommend this because if the level on the receiver is set under 0dB, then sometimes the signal transferred over the cable is not high enough to trigger the sub to turn on (or high enough to keep it turned on), and your sub will be turning on and off during a movie. It's happened to me, and I've read on here about others who have experienced this.

 

[jaseman]

Hey MDS, and Adam, thank you both for your input. Yes the receiver can adjust the line level either by 5 points at a time or in single digit increments. It does make sense to keep the level high enough so that the sub doesn't shut itself off. When watching normal TV I hear it shut off from time-to-time.

It just seems that it would make sense to build the receiver so that the line level is always strong enough at the source and then you can adjust with the volume on the sub itself. I mean why even have the option to turn the line level down so low that the sub barely receives any signal??? Anyway, I will keep it at the factory level of 10 for starters. I do have a SPL meter. I am just waiting on my new 7.1 setup to arrive in about a week and a half to get it all setup again.

I do have another question that I have researched many times before and would appreciate your opinions on: This receiver's lowest x-over setting is 80 which is the normal THX setting. What if I were to run the high-level front L&R speaker wires to the SUB, set the x-over on the SUB to 60 and let it pass what frequencies the fronts get???

The reason I ask is because I used to have a passive SUB many years ago that connected like this and quite frankly it sounded very good. Especially when watching Apollo 13, right before the launch where the music plays really low did the passive SUB sound fantastic... not so much with a powered SUB of better quality. If I were to try this, would I set the speaker sizes all to small, the same as I would with the line level hookup to the SUB? Or would that limit the low end frequencies needed by the SUB?

Thanks again for all your responses!

 

[Adam]

It just seems that it would make sense to build the receiver so that the line level is always strong enough at the source and then you can adjust with the volume on the sub itself. I mean why even have the option to turn the line level down so low that the sub barely receives any signal???

Yeah, I hear ya. If you have your sub always on, then this will never become an issue. It's when you have a sub set to automatically turn on that this might present itself. It's a combination of the level of the signal being sent to the sub and the required threshold of the sub for that signal to turn the sub on. The ability to change the volume of the sub with the receiver is just a convenience item.

I do have another question that I have researched many times before and would appreciate your opinions on: This receiver's lowest x-over setting is 80 which is the normal THX setting. What if I were to run the high-level front L&R speaker wires to the SUB, set the x-over on the SUB to 60 and let it pass what frequencies the fronts get???

The reason I ask is because I used to have a passive SUB many years ago that connected like this and quite frankly it sounded very good. Especially when watching Apollo 13, right before the launch where the music plays really low did the passive SUB sound fantastic... not so much with a powered SUB of better quality. If I were to try this, would I set the speaker sizes all to small, the same as I would with the line level hookup to the SUB? Or would that limit the low end frequencies needed by the SUB?

People have varying opinions on the "best" or "right" way to connect a sub, but in my opinion it comes down to personal preference. Connecting the front L&R speaker wires to the sub and running it the way that you suggested certainly shouldn't damage anything. If you prefer the way that it sounds like that, then I say go for it. If you do that, set the front speakers to LARGE, do not connect the line level input to the sub, and set it up in your receiver so that bass is redirected to the front speakers. Doing that will direct the low frequencies out through the front L&R speaker wires, which you would have passing through the sub.

Regarding the passive sub, there could be any number of reasons that you preferred it to the powered subs that you've heard. One that comes to mind is where you had it located in the room. There can be big changes in the frequency response at your listening position by moving the sub just a few inches. Another that comes to mind is that the sub might have had higher output in a specific frequency band that just sounded good to you. So, not a flat response like a good sub is intended to have, but one with a bump that sounded good (I hear that car subwoofers are like this).

When I was younger, I had some Radio Shack speakers with 15" woofers that would vibrate the walls when I played a certain song. I loved it. I cannot recreate that with my far more expensive powered sub. However, I'm not in the same house (nor even a house with the same sort of construction), let alone in the same house with the subwoofer placed in the exact spot as the other speakers. So, I don't blame the sub. I think that it's a combination of several things.

BTW, what 7.1 speaker system are you getting?

 

[jaseman]

"BTW, what 7.1 speaker system are you getting?"


I am getting the system from Axiom.
Center = VP150
Fronts = 2xM60 v2's
Surrounds = 4xQS8's
Sub = EP500

 

[Adam]

"BTW, what 7.1 speaker system are you getting?"


I am getting the system from Axiom.
Center = VP150
Fronts = 2xM60 v2's
Surrounds = 4xQS8's
Sub = EP500

Wow, nice! That's quite a set that you're getting. Perhaps after you get it all set up you can start another thread and let us know how you like those.

I have no experience with the Panasonic SA-XR55 receiver, but based on the specs, I wonder if it's going to supply sufficient power to really bring out the best in those speakers. Of course, you gotta try it out first. If it sounds good, then fantastic. I just mention it because it's one of the first things that popped into my head.

 

[jaseman]

Yes, I was wondering about the power myself. Right now I have a mix-and-match 7.1 setup running off of this receiver and it sounds quite good. My current setup is:

Center = Polk something..at work can't remember...it's about a year or two old, has 2-5" drivers and 1-1" tweater...sounds good though!

Fronts = 2x KLH 9150's 4way speakers.
Surrounds = 4x Sony bookshelves, with 1-1" tweater and a 5" driver in each. Two of them are a couple of years older than the other two but they are basically the same. Cost about $40.00 each. Sound pretty good.

Sub = sheesh...I can't remember it's name!!!! 10" woofer...basically sucks but it's OK. I have bass shakers under all the seeting so you still feel the boom-boom's.

The Panasonic was highly rated over at AVSforum when it came out and it really does a wonderful job powering my current system. I expect that it will do equaly well with the new one.

I will keep everyone posted when the new speakers are in place and up to speed!

 

[autoboy]

I think you will love that setup. I have a similar system,

M60v2
vp100
QS8
SVS PB-12 sub
Sony reciever that sounds good to me

I have had the same questions as you about line level input to the sub. My Sony reciever has separate crossovers for each speaker. Right now I have it set up with the fronts at 60hz, the center at 120hz, and the rears at 120hz.

My sub starts to fall off on the high end around 80hz. Yours is much more linear because it has an electronic circuit that keeps it linear. I set the fronts, which fall off at 38hz, to 60hz so the sub would not have to handle 60-120hz signals. I'm not sure how the reciever routes all the bass around the system. If the reciever routes the 120-60hz signal from the center and surround to the fronts, then the fronts, center, and surround 60hz-15hz signal is routed to the sub, this setup is perfect and does not leave any holes. The mid-low bass that comes from the center is evenly distributed to the fronts, and the low bass is handled by the sub, preserving the soundstage. Some have said that the sub will get all the signals from the crossover. That means that the 120hz and below from the center would be handed to the sub, and the 60hz and below from the fronts would be handled by the sub. However, that leaves me with a gaping hole because the subs high point is 80hz, and it gets up to 120hz in midbass from the center and surrounds. A EP500 can handle 120hz linearly so this will not be a problem for the axiom sub.

If I hooked up the sub to the line level from the fronts, and set them to large, all the bass from the entire system would be handed to the fronts and then the sub would take only the 60hz and below. Is this the way I should set it up?

Also, one more thing, once in awhile I like to listen to music without the sub. The m60s are perfect for rock and the bass is much more tight than the low end SVS sub (but damn that SVS hits hard and low). Hooking up the line level will prevent me from running pure 2 channel. This is not super inportant though. I'm 95% movies anyways.

 

[jaseman]

I guess all we can do is experiment with hooking up the line level to the sub and use it's x-over to see what sounds better. My only concern with your setup is the way you have your center x-over set. I would think that 120 is a little high for a center that is rated down between 65 and 95.

Seeing how the center carries 80% to 90% of the total sound in a movie track I would be worried that I'm losing something in the dialogue pushing it all to the fronts. But, you are the one listening to it so only you can tell what sounds the best.