what the difference between 0db, -3db, -6db etc test tones?

[T3mpest 10+ year member]

IMO setting by ear is the best way. As others mentioned, impedcence rise, what the woofers can take mechanically (not thermally and this varies with frequency), etc all play a factor in power handling. Plus music is dynamic, if you set it with a 0db test tone speakers will ALWAYS see less than RMS, usually 3 to 6db's worth of power down from that, which is a factor of 2-4x. 0db tones means yeah, you won't ever clip the amp, but if the amp clips at RMS, your also sending 1/2 of their RMS wattage to them on average, on loud songs too. Gain setting isn't rocket science. The only reason it's hard for this forum is because most them want to run their subs as loud as they can and dont' care how it blends with the music at all, nor do they care if it distorts. Start with gains all the way down. Turn hu up to about 3/4 volume, and raise the gains on your fronts on a loud recorded song. Most everything nowadays is, just pick something you know, helps to have vocals. Turn the gains up a bit at a time until it's either loud enough or you hear it begin to distort, usually the vocals will begin to sound funny, you'll pick it out before it's bad enough to damage anything in most cases. Then play some hard hitting rap and do the same thing with the sub. At some point the subs will stop getting louder as the gain go up, if that happens, turn them down a hair and leave it alone. If you see the cone is stressing by moving to far, turn it down. It's pretty hard to break equipment without any warning signs.

 

[OmegaBunny 10+ year member]

K...I'll give it a shot:uhoh:

 

[bubbagumper6 5,000+ posts]

Jesus christ, so much misinformation in this thread it's not even funny. Setting your gains with a -6db test tone will cause you to set the gain HIGHER than if you were to set them with a 0db tone. Setting them by ear is NOT an accurate way to insure your not clipping especially since it's obvious your fairly new to the game and have no idea what to listen for (no offense). Setting your gains with a 0db test tone will in NO WAY hurt your system. Worst case scenario is you will have the gain lower than what it could possibly be at and it won't be as loud. Plenty of people have been using the DMM method for years and I can pretty much guarantee you they've blown less amps because of clipping than the noobs who set the gain by ear.

 

[T3mpest 10+ year member]

lol a 0db test tone means it's recorded at reference level, 0 decibels below the peak level capable of being recorded onto a cd. a -6 tone is 6db's quieter than that. If a tone at 0db's puts out 1000 watts from the amp, a -6 tone will put out 4000. So yes, a 0db tone is louder than a -6, so gains will be lower with a 0db for the same output. If you set gains with a 0db tone, your gains will be very low and you wont' see much power out of the amp on any tone other than a 0db peak on a recording. setting at -3 or -6 means you'll get close to RMS power at the normal parts of the song. SPL guys set gains with tones because they are pushing things to the absolute limits and will be burping with that exact tone. Granted I come from more of a SQ oriented mindset, where people know how to properly use their equipment and dont' tend to overdrive things constantly. If your that scared, use a 0db tone, just dont' wonder why that that tone got loud but as soon as you pop in a cd, everything is quiet. Techically anythign other than a 0db tone will probably clip part of the time, but that also guarantees you'l never see alot of the power from the amp either. If you don't trust your ears and find 0db is really quiet try a -3.

 

[KyleBechtold 5,000+ posts]

No. -6 means negative 6. What does negative do? it reduces. And dont use a DMM to set your gains...that does not work.

no you got it wrong here.. setting your gains on -6db music means when you play 0db music. it will be 6dbs louder than if you set it at 0db.. the lower you set your music on will make the actual music louder.. -6b on -6db music would be 0db difference setting it with -6db music and playing -3db would be 3 dbs louder than the test settings.. therefore voltage amperage etc will be higher

 

[T3mpest 10+ year member]

correct. Music jumps around alot though which leaves you with rough estimations. Speakers that are rated in pro audio are done as follows. They use pink noise as a signal, -6db's at the given RMS they wish to test the speaker at. Pink noise has energy spread thorughout the spectrum so it's similar to music in frequency content. They run that for 15 minutes, burst the speaker with a 0db tone, so 4x rms for a split second and then repeat that for a 2hr period. If the speaker passes that RMS value, the up it until it fails. Whatever value it can take for 2hrs max is the continous power handling.

 

[OmegaBunny 10+ year member]

K I reset my gains with a -6db test tone and DMM setting it for 900 watts. Amp is rated for 950. So I am hoping I Will be okay //content.invisioncic.com/y282845/emoticons/frown.gif.a3531fa0534503350665a1e957861287.gif I was thinking about doing it by ear but know I run a higher risk of damaging something. After I set it, I listened to some different music and didn't hear any noticeable distortion so it seems okay. I will keep checking it to make sure its fine.

 

[OmegaBunny 10+ year member]

Setting your gains with a -6db test tone will cause you to set the gain HIGHER than if you were to set them with a 0db tone. .

K so if I set it at 900w with a DMM on a -6db tone, will it really be 900w or will it actually be higher? I understand that it will be higher than a 0db tone. What is the best way to get it as close to rated without going over. In novice speak if you can. I know that no matter what it will not be doing peak because of voltage drops and what not but I really want to get the most out of everything.

Also, No offense taken by me I am a noob and want to make sure I don't screw something up. I know a little so maybe I am an advanced noob.

 

[RLJ676 10+ year member]

No matter where you're gain is, if you are listening to music and it sounds off, you are too loud. Different music will stress the system to varying degrees, even at the same "volume level" on the knob. Different frequencies and recording levels (amongst other stuff) will impact this.

This isn't rocket science guys, don't overthink it. Hell, crank all the gains all the way up, and then don't listen to the music at distorted levels. This requires simply adjusting the volume based on the song.

 

[n2audio 5,000+ posts]

I would go no lower than -3db tones for DMM gain settings.

I use 0dB, but I understand why someone might want to use -3.

In the past I have set them by ear then measured with a DMM and 0db just to see if they are very close, and they were.

I frequently load music files in adobe audition which monitors db levels of the signal. MOST songs I have looked at reach 0db at some point, and some exceed that (clip) frequently, although the average dB level of the entire song is often -10db or less.

I agree with RLJ. It's not as big of a deal as some people make it.

You don't need an o-scope, clamp meter, rms meter, flux capacitor, and a super dooper gain setter tool.

Set them somewhere reasonable. Use some common sense to get the subs to blend with the mains.

Then listen as you please. If you hear a hint of distortion here and there, turn it down a bit. If you hear no distortion and you think the speakers/subs have more to give - turn them up a bit.

There's really no "right" way for them to be set. There's "what sounds good" and "within reason".