sub volume level

Discussion in 'Archived Threads 2001-2004' started by allan espinoza, Jul 11, 2002.

  1. allan espinoza

    allan espinoza Stunt Coordinator

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    i was wandering how high does everybody turn their subwoofer up? how high is it reccomended to turn it up?
     
  2. Scott*E

    Scott*E Stunt Coordinator

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    It depends on the wattage of your subwoofer's amp. My Sony reciever is 100 watts per channel but my sub's amp is only 80 so I have to turn it up kind of high, about 3/4 the way. If I had a more powerfull sub amp the volume knob would be turned down lower. Bottom line is don't go by numbers, go by what sounds best in your room. Just keep increasing the sub's volume untill it blends in well with your other speakers.
     
  3. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    People often over-simplify this issue with statements like:
    "My sub rocks and its only turned up 1/3 of the way ... its got LOTS of headroom"

    But its important to remember that there are actually THREE gain controls in the system. The first is the obvious gain/volume control on the sub itself. The second is the subwoofer level control built into the receiver's speaker level controls. The third is the volume control on the receiver. And if you're running some kind of equalization or have the "bass" knob turned up that will confuse the matter even further.

    I could crank my receiver's subwoofer level up to maximum and then the gain control on the sub itself could be pretty low and the sub would still crank. Or I could turn the receiver's subwoofer level way down and crank the gain control on the sub way up and get to the same overall level.

    Looking at only one of the three gain controls tell you virtually nothing about how hard the sub is working. In general we try to balance these gains so that neither the sub gain or the receiver's subwoofer level is near the top of its range. If you're using a pro amp to drive a passive sub then you've got a whole different case and you'll likely have to crank the pro amp gain all the way up.
     
  4. John Garcia

    John Garcia Executive Producer

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    In addition to what Ryan said (very good info), you also need to do a level and phase calibration with a test disc and SPL meter to be able to adjust all these parameters correctly.
     
  5. BrianWoerndle

    BrianWoerndle Supporting Actor

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    Every sub, in every room will be different. It needs to be properly calibrated with test disc. Ryan had many good points that affect performance. It can't just be stated as 1-10
     
  6. jeff lam

    jeff lam Screenwriter

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    How high it's turned up has nothing to do with how good it is or how loud it can go. Most of it is in the input sensitivity and input impedance of the amp compared to the output voltage and output impedance of your sub level output on your receiver or preamp. A sub that's only turned up 1/10 of the way can still clip. You have to understand that the amp has limits and they can be exceeded with a high enough voltage from your preamp.

    For example, say I have a yamaha receiver with a 4V sub output with a 1.2Kohm impedance. You have a denon with a 1.4V output with a 1.2Kohm impedance. We both have the exact same sub and same room. You would have to set your sub amp gain much higher than I would because your sub output level from your receiver is much lower than my Yamaha.
    This is just an example. Sub amps are all different too. Some have higher input sensitivity than others. Just because you reach calibration at 1/10th the way up doesn't mean your sub can still play 10x's louder. It just means it was supplied with enough voltage to drive the amp to calibration with it only being 1/10th of the way up.

    My calibration method is:

    1. set your sub output level on your preamp/receiver to 1/4th the way up(If the range is -20 to 0, set it to -15). This gives you room to adjust up and down without going over the 1/2 way setting which distortion starts to be induced above 1/2 way.

    2. Once the sub output level is set on your receiver, turn up the sub amp gain till you read the proper calibration level on your spl meter at your set reference volume. This setting could be 1/2 way, it could be 1/10th way, or it could be 9/10ths way up. It all depends on your sub, receiver, room, etc.
     
  7. Bill Kane

    Bill Kane Screenwriter

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    Very good information.
    Just to clarify:
     
  8. Neil Joseph

    Neil Joseph Lead Actor

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    I am running my sub about 4dB hot (79dB) according to the Radio Shack meter.
     
  9. Vince Maskeeper

    Vince Maskeeper Producer

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    I would say for many configurations this would be less than ideal. As I've posted a few times, depending on the design of the amplifier stage in the subwoofer- there is a reasonably good chance you are decreasing the audio quality unless you run it all the way open.

    Especially if you use an out board amplifier (like with SVS subs)- the "volume" control on the amp does not control output so much as it regulates input.

    In other words, often the control on the amp for the sub
    is unable to "boost" the signal it receives- rather the MAXIMUM position simply means it is not reducing the signal it receives. So, any position other than full on is attenuating the signal. In some cases, and in some designs this is a non issue- but in others it makes an impact in the quality of the output.

    Depending on your configuration- it might very well be better to run the sub full on, and control the level using the receiver speaker level control. If you cannot possibly get the system calibrated with the sub at max (you turn the sub send on the receiver all the way down and it's still too loud)- then you should reduce the amp setting. But if you can get the system calibrated with the amp at full tilt- I would absolutely run it that way.

    -V
     
  10. Bill Polley

    Bill Polley Second Unit

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  11. Marc H

    Marc H Second Unit

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    My sub has a bypass input so the level control doesn't function and I run the LFE out on the receiver at 0dB.
    I would assume the bypass input is full gain but don't know for sure.
     
  12. jeff lam

    jeff lam Screenwriter

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  13. JohnDG

    JohnDG Stunt Coordinator

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  14. jeff lam

    jeff lam Screenwriter

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  15. Vince Maskeeper

    Vince Maskeeper Producer

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    Jeff,

    I had my first sub which used a plate style amp- and the volume worked exactly as a professional style amplifier-- it could not boost- rather full tilt was 100% unfiltered.

    So, the moral of the story is that there are also some plate amps out there that work this way- and many on the forum have found improvement by running this way with plate amps...

    So the best advice is to experiment (carefully!)

    -V
     
  16. aldamon

    aldamon Second Unit

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    [​IMG]
    I have the DLS 10" sub and I'm having trouble with sub tests too. I have the Sound & Vision DVD. On the DVD, it says to turn the sub level all the way DOWN on the receiver and sub itself and then use the knob on the sub to turn it up during the tests. I ignored this and did what I read on this board in several posts: turn the level up half way up on the sub and use the receiver's controls to boost the bass beyond that point. Now, I see Vince's post here and he says that I'm supposed to turn it all the way up on the sub and use the receiver to drop the bass! That's three methods from three sources! What's right? For a newb like me, the contradictions are stifling.
    All of this is moot though since the needle on the Radio Shack SPL meter jumps all over the place during the sub tones on S&V. Is the needle supposed to jump like that? I'd like to get the correct level, but I'm not experienced enough to know what "correct" bass sounds like by ear or "experiment" on my own. The needle doesn't jump during the other five channels.
     
  17. Vince Maskeeper

    Vince Maskeeper Producer

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    I have the Sound & Vision DVD. On the DVD, it says to turn the sub level all the way DOWN on the receiver and sub itself and then use the knob on the sub to turn it up during the tests. I ignored this and did what I read on this board in several posts: turn the level up half way up on the sub and use the receiver's controls to boost the bass beyond that point. Now, I see Vince's post here and he says that I'm supposed to turn it all the way up on the sub and use the receiver to drop the bass! That's three methods from three sources! What's right?


    The answer is, all of them and none of them are right!

    The reason why there are options in the first place is because no two configurations are absolutely identical. If you are looking for absolute correct answers in 100% of cases, I would suggest the audio world is not the place to find them.

    Method One
    Your S&V DVD suggests to turn the sub output all the way down and adjust at the sub volume itself. This is good advice to give the entry level person which will work and won't risk damaging anything in the signal chain.

    Using this approach, you will get clean output from the receiver (because the sub send is all the way down) and best of all there is essentially zero chance anyone will blow up their speakers because they are increasing the volume starting from nothing directly at the sub.

    Even if you were to start at 1/2 on the sub volume and all the way down on the receiver output- there will be an initial tone produced at "unknown" level. If I was designing a test DVD to be sold to anyone with $15, I would play it safe and do exactly as the S&V disc did- play it as safe as possible and don't risk damaging anything!

    Chances are reasonably good that you will increase the sub volume to max or near max- and then need to boost at the receiver to get the proper level... so you basically end up in the same ending point (Sub at Max, Receiver real low) as you do with Method Three (The Vince Method)!

    Method Two
    People on this forum have suggested start with the sub at the 1/2 way point and work from there. This is the best catch all solution that will work for nearly everyone-- no matter how your amplifier works, this method will achieve the desired results, although it may/may not be ideal for your specific configuration.. While the above method played it 100% safe, this method assumes that there will be little chance to produce a damaging tone at 1/2 volume and the receiver all the way down.

    1/2 Volume is just a simple median point, a starting point which anyone can latch onto. Just like in any other case, if you find yourself pushing the receiver sub output past +2 or +3, you usually want to start over, and boost the sub volume a little. In the end, the goal is basically the same (balance the level without running the receiver too hot)- but this method serves the purpose of a basic "starting point" which most on this forum have latched onto.

    Method Three
    In my opinion the goal is to get the receiver output as low as possible and the subwoofer input as high as possible.

    Couple this with the fact that there is a particular amplifier design (which is the majority of rack mount pro style amps, and at least a few plate amps) in which the volume knob is not a "volume" but rather an input regulator which is only able to attenuate the signal down. So, on these style amps, unless the volume is at max- the signal is being "filtered" in one way or another to reduce the amount being passed to the amp stage. In these cases, you yield the best possible performance by running the amplifier "volume" (input controls) full on and allow signal to flow unaltered from the source to the amp...

    So, with these two issues in mind- I suggest running full bore, if you can, and regulating at the preamp. The obvious concern here is the issue of damaging equipment. If I was describing the process to my in-laws, I wouldn't suggest this method as there is waaaaaay too much potential to fry something. However, in many configurations, this will yield the best results-- so for more savvy users, I make this suggestion (and suggest that they experiment carefully).

    The problem is, of course, that not all configurations of amplifiers are as I described them above (some plate amps actually allow you to BOOST the signal coming in using the volume knob on the sub)-- so the advise is always to experiment (with caution) to find what works best for you.


    The bottom line is, the goal is essentially the same: get calibrated output without running the receiver sub output too hot (as it is known to distort). Because there are different ways amplifiers can work, and therefor different ideals for their configuration- it's tought to give an answer of how to approach it. You can either pick a generic that works for all configs (but might miss out on potential in some) like Method 2, or you can try for what might be the idel for half the people- and let folks work tehir way back if it doesn't work for them (Like Method 3)...

    S&V takes the safe route to this end by telling you to set the receiver at minimum and boost the sub until you get there (presumably they would suggest if you can't "get there" with the sub at max- then you start increasing the receiver output-- so if you think about it you end up exactly where you would with method three). They prevent damage and reach the same desired destination.

    The popular forum method has the same goal and takes a more "this will work for everyone" approach-- start in the middle and work your way to where you need to go. Again- the idea is to keep the sub send below +3, so in the end you might very well end up boosting the sub to keep the receiver output as low as possible. This method simply takes into consideration that there are multiple amplifier design types- and while this might not be the ideal for all- it will certainly work for all!

    The "Vince method" again seeks the exact same goal (minimal receiver output) but simply starts with the sub at max and works backwards from the S&V method (which of course does offer a real possible risk to your gear if you don't know what you're doing). While my method might not be the ideal for all configurations- it would offer a marked improvement in several of them, so instead of offering a middle-ground catch all (as method 2 does)- I suggest going full on and working backwards if it doesn't work for you.

    Hope that makes more sense.


    All of this is moot though since the needle on the Radio Shack SPL meter jumps all over the place during the sub tones on S&V. Is the needle supposed to jump like that? I'd like to get the correct level, but I'm not experienced enough to know what "correct" bass sounds like by ear or "experiment" on my own. The needle doesn't jump during the other five channels.


    Depending on how the material is filtered, you will get some jumping (it's just the way bass material works). Usually the advice is to set the meter to slow and look for the average (this is much easier, IMHO, with the analog meter). After playing a bit you'll get the hang of it.

    -Vince
     
  18. aldamon

    aldamon Second Unit

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    Wow Vince! I know I'm a n00b, but that post looks like Primer material to me!

    Thanks!
     
  19. Ryan Schnacke

    Ryan Schnacke Supporting Actor

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    Vince, I don't mean to stir up trouble but I'm curious about your statement
     
  20. jeff lam

    jeff lam Screenwriter

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    Unless you have a very weak receiver sub output, any of the PE plate amps will be impossible to calibrate to proper reference level with the gain up all the way. You will be far above reference even with the sub level on the receiver near minimum.
     

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