# Subwoofer Level



## Malazan (Apr 13, 2012)

On my head unit, I have a subwoofer Level Adjustment from -15db to +15 DB

What exactly does this do? Also, when I set my gains with a DMM, what should this Adjustment be set too?



Thanks,

John


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## Khymera-B (Oct 6, 2009)

Its basically a volume control for the subwoofer's signal.


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## trumpet (Nov 14, 2010)

Set the subwoofer level to +15 when setting the amplifier gain.


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## Khymera-B (Oct 6, 2009)

trumpet said:


> Set the subwoofer level to +15 when setting the amplifier gain.


I wasn't quite sure so I didn't answer.


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## SoundChaser (Apr 3, 2009)

trumpet said:


> Set the subwoofer level to +15 when setting the amplifier gain.


Why?

Depending on the music and the recording, at times you’re going to want more then +15 and you will not have it. 

Personally, I would set it halfway (0). This way you can go either direction on the fly.


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## Khymera-B (Oct 6, 2009)

SoundChaser said:


> Why?
> 
> Depending on the music and the recording, at times you’re going to want more then +15 and you will not have it.
> 
> Personally, I would set it halfway (0). This way you can go either direction on the fly.


I like to limit my levels personally. I test with the best recordings I have available.


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## crispin (May 23, 2011)

trumpet said:


> Set the subwoofer level to +15 when setting the amplifier gain.


That is not right at all

1) the HU likely produces distortion at a +15 level

2) if OP wants to play his music down low but have the bass up higher (which I like) he would have no way with your method.

OP set it at '0'


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## SoundChaser (Apr 3, 2009)

Khymera-B said:


> I like to limit my levels personally. I test with the best recordings I have available.


What happens when you put in ****ty recordings that lack bass? 

Actually, if you max out your level to +15 you’re better off adjusting your gains with music that has low bass output. This way you can scale back as needed with decent recordings.


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## Khymera-B (Oct 6, 2009)

SoundChaser said:


> What happens when you put in ****ty recordings that lack bass?
> 
> Actually, if you max out your level to +15 you’re better off adjusting your gains with music that has low bass output. This way you can scale back as needed with decent recordings.


I play ****ty recordings all day. I limit it because others drive my car and push the limits of the sub too much. If it was just me, I wouldn't worry about it. Not saying anyone should follow my setting, it's just the way I like to keep my current setup and ride.


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## Cruzer (Jul 16, 2010)

i guess im an odd ball. i never adjust my sub level on the fly. i feel if i set it right its going to be at the level required for all songs/music

i would try 0 and set gains. if ur gains are maxed out, then try say +3 and try setting gains again.

you dont want ur amp gains maxed if possible and if possible u want to avoid having the sub level +15 in case it the head unit does distort.

i have my sub level at its max +6db and it does not distort at all in the slightest. if it matters i play 320kbps songs only

imho a quality head unit will not distort but im just a noob so i dont know for sure


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## nosaj122081 (Apr 7, 2012)

I set gains with the sub level all the way up, too, but I use tones and a scope to set gains. I use a -6dB tone on the subs, with the sub level all the way up and the volume all the way up (my Clarion doesn't clip, even at full volume and a 0dB att. tone).

My front stage amp I use a -3dB tone to set gains, so the sub gain is higher by default. Using the -6dB test tone, I know I can turn the sub volume up completely and the chances of the input signal clipping is very, very low. I play LOTS of piss-poor quality recordings, out of necessity.


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## bigguy2010 (May 18, 2010)

Leave it at 0. That way you can go up or down with the adjustment, to match what you're listening to. I rarely turn my down but sometime do bump it up a little bit. Maybe my amp gain is just to low.


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## Spyke (Apr 20, 2012)

I love this subjective hobby. I'm guessing you have a kenwood hu, if not it doesn't matter. On my hu anything past I think 9 is boosting the signal more than the other preouts. So a hu with 4v preouts is putting out closer to 5v with the sub level at 15 on the sub channel. Again this is just my hu. What ever method you decide to use just make sure your gain doesn't go past half way. If it's cranking at 18 out of 35 on the volume then turn down your gains. Loud on my setups is usually at around 31 out of 35 with the sub level at 7. Basically you want you preout signal as strong as possible with the gains as low as possible. Hope this helps.


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## trumpet (Nov 14, 2010)

If you don't get enough output by setting the gain with a 0 dB test tone and the sub level maxed on the head unit you need to be prepared to clip the amp, possibly quite a bit, if you set the sub level lower. Usually the head unit subwoofer level is attenuating the output voltage at anything less than max. You can compensate by using an attenuated test tone, like -3 dB or -5 dB.

Amplifier gain setting for your own system is open to interpretation, but professionals need to have something repeatable and quantifiable for when the customer comes back and has a complaint. One such method is to use a DMM, others may use an oscilloscope, and some installers just use their ears. Another way is to use the SMD DD-1. Stephen Mantz of Zed doesn't even recommend sine wave test tones as he writes that it's very hard on an amplifier. He advises the use of pink noise. So, as you can see, there are a lot of "right" ways to set your gain. Which way is right for you?


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## Malazan (Apr 13, 2012)

Thanks for all the replies, I found this:

GlassWolf's Pages


He says to set Gains with the Sub Level at Max


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## bigguy2010 (May 18, 2010)

Spyke said:


> Basically you want you preout signal as strong as possible with the gains as low as possible. Hope this helps.


^ THIS


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## ScottyGreen (Apr 3, 2012)

I agree with "bigguy2010" too...
I personally set mine at 7+ on my headunit so I don't have to turn up my gain very far on the sub amp and it also gives me a little room to turn it up higher on my HU if playing a poorly recorded track. It offers me a good balance. I disagree with setting it at 0 because your sub amp will have to work much harder than it needs to and you'll be further straining your electrical system. IF I set my HU to 0 on sub my headlights dim alot because my gains have to be higher on the amp, if I set it to 7 my headlights don't dim much because the amp isn't having to work nearly as hard.

You want your sub amp (or any amp for that matter) to have as good/high of an input signal as possible BEFORE adjusting it's gains. I also would not peg it on the HU at 15 because you can't turn it up then on poor quality recordings.

Just my personal preference, but there is some strong evidence that this way will result in better system balance and user "happiness" overall...


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## Spyke (Apr 20, 2012)

ScottyGreen said:


> I agree with "bigguy2010" too...
> I personally set mine at 7+ on my headunit so I don't have to turn up my gain very far on the sub amp and it also gives me a little room to turn it up higher on my HU if playing a poorly recorded track. It offers me a good balance. I disagree with setting it at 0 because your sub amp will have to work much harder than it needs to and you'll be further straining your electrical system. IF I set my HU to 0 on sub my headlights dim alot because my gains have to be higher on the amp, if I set it to 7 my headlights don't dim much because the amp isn't having to work nearly as hard.
> 
> You want your sub amp (or any amp for that matter) to have as good/high of an input signal as possible BEFORE adjusting it's gains. I also would not peg it on the HU at 15 because you can't turn it up then on poor quality recordings.
> ...


This too^


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## bigguy2010 (May 18, 2010)

ScottyGreen said:


> You want your sub amp (or any amp for that matter) to have as good/high of an input signal as possible BEFORE adjusting it's gains. I also would not peg it on the HU at 15 because you can't turn it up then on poor quality recordings.


Couldn't agree more here. Just send the amplifier clean signal to begin with and you'll have better results overall. Also try to eliminate anything in the signal path. I don't use line drivers or processors. Just let the hu do it's job.


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## mkvy1 (Sep 20, 2016)

Heres my story.
Had quite a few subwoofer enclosure designs over the last few years. Ram and PWK.
Never realised how utterly important the actual low pass filter and subsonic filter were in these designs. For years i always had it set to 100 htz, just because i read it somewhere. Some tracks sounded great but others sounded muddled and strained.. i always played with gain thinking this was the cause..
So i started experimenting with SMD DD1 and CC1. Gain and crossover tools.

i set the subwoofer gain using -10db overlap. My kenwood unit does not distort at max volume 35/35 = 2.7 v preout )
i set my Mids/highs gain amp using -5db track

Subwoofer level on the headunit is at zero. 
this -10bd/-5db gain structure can then be changed if needed by using subwoofer level or gain control within the headunits menu.. Perfect!

if i feel like SMD's gain structure for 'sound quality', i just dial in -5 on the sub level from the head unit giving me a net -5db/-5db gain structure

my Low pass filter is now set at 63 Htz, subsonic filter 28 Htz. Now the music is way way better.. The mids and highs are crossed over at 63Htz
all 24db slopes.. Amazing!!

Why i did not try this before i do not know?


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## bugsplat (Nov 7, 2014)

Spyke said:


> Basically you want you preout signal as strong as possible with the gains as low as possible. Hope this helps.


DING DING DING!

Right answer. The HU should have its preout tested to find that upper limit before clipping. You can test with -10db (conservative/safe), -5db (average, leaves room for adjustments), -0db (****-it, turn it up) tracks to see what your HU's max output is. That max output is what you want to send to your amps. The highest output your HU will send without clipping. If you hand your amps a strong, clean signal you giving them the best food you could feed them. From there the amps have a solid signal to amplify.

Setting your HU levels to 15db may not be wise because it does not leave you a lot of room to adjust. While this will assure that you could never send a clipped signal, you wont be able to adjust later. If it were me, I'd test with my HU max out put before clipping with a -5db track and just know I can't set my HU levels above +5db later. That gives me 5db to play with. Another thing, and I know its a pain in the ass but once you lock down your highest non-clipping levels try to only adjust your levels down, not up. If you are lacking say sub levels (20hz-80hz) adjust your mids and tweeters down to meet the sub. Don't pull your sub up to try and play as loud as the mids/tweeters. If they are all adjusted properly and the volume is still too low then it may be time to look at bigger amps with more watts and or more efficient speakers.

This is all crossing over into the Active audio realm. This is why so many go with a digital signal processor. It allows us to control the levels, timing, slope and phase at a very fine level. For the average person testing with your HU at 0db or +5db or even +10db might be fine to stay in safe levels. An active system will tell you if your max is +10.75db or even in my case, -2.35db and not a smudge more. The owner is trying to get as much out of his or her system without decreasing quality.


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## brother_c (Sep 21, 2015)

I've seen on several HU's that increasing the Sub level control beyond 0 dB will cause clipping at a lower Vrms output. I use a 0 dB tone to find the max volume level without clipping from the HU. Then use an attenuated -6 or -12dB test tone and measure the output of the amplifier speaker terminal and then find the maximum gain level without clipping. Then use 0dB subwoofer level as max volume, and only decrease the Sub level. YMMV


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## Weigel21 (Sep 8, 2014)

So on an Alpine HU's, you leave the HU's sub control at it's minimum 0 level and never dial up past that (or lower since you obviously can't)? That makes absolutely no sense to me in the least, no offense. 

My last HU (Sony DSX-S200X) could have it's sub level at it's maximum of +10 and not produce distortion until one click afteer the point on the HU's main volume dial that the front and rear preamp outputs did while playing (IIRC) a 250Hz 0dB test tone. That frequency, with that HU, distorted sooner than any other frequency I tested. 

I'm FAR from a bass head and a good leap from a audiophile too, but I've generally not had any issues getting enough output from my sub(s) with setting the sub level to it's maximum level when setting amp gains. Only ran across a few poor recordings that really had me feeling a bit cheated in my lows. However, most of my music collection is 320kbps MP3s ripped directly from the disc using EAC and Lame. Off the top of my head, the only track that comes to mind that seemed weak in output was "My December" by Linkin Park, as I had to download it using LimeWire years back since it didn't seem to be a track ever released on CD. I know there's more, just not coming to mind right now. However, all of them were downloaded tracks, which that right there is the problem. 

Actually, you know what, right now, my current setup does in fact seem a bit lacking, but it's not just in the lows, it's EVERYTHING. Imprint kind of sucks. Seems I'll have to take a lot of steps to get not only a good tune, but adequate output. As it is, the HU's output for the components doesn't seem to get any louder past volume level 25 and the sub doesn't seem to get any louder past 30. Turn off Imprint and the system wants to blow out my ear drums (damn Hyperacusis). So, it's not that my system can't get loud enough, it's that Imprint attenuates the hell out of everything, probably to level match with the weakest output frequency. Not thrilled, not in the least. 

I mean it is clean and does sound fairly good cranked up to 25, but a lot of my music just doesn't seem loud enough, which really is a surprise to hear myself say. Not sure if it's the way it's supposed to be, but the sound stage/imaging I get has the vocal at roughly the center of the car about chest height. Thought it was supposed to be higher than that. 

Sorry, thread jack over.


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## brother_c (Sep 21, 2015)

Weigel21 said:


> So on an Alpine HU's, you leave the HU's sub control at it's minimum 0 level and never dial up past that (or lower since you obviously can't)? That makes absolutely no sense to me in the least, no offense.


No offense taken. Just from my personal experience after being shown from a guy who scopes every new model HU that he brings in. Many of the newer units can't play a 0dB tone at max volume without clipping, and boosting the Sub level causes clipping sooner. My Pioneer 4000 NEX would start to show small signs of clipping above 2.4 Vrms output with all levels at 0 dB. Adding more than +2dB to the sub level would be clip city at a lower volume.

Older units can run full wide open and it's a beautiful sine wave. Not much music is recorded at 0dB, music is dynamic, ymmv. Was only sharing what I've learned.


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