Setting Gain

[bubbagumper6 5,000+ posts]

You had the subs disconnected right? Then after you set it, you reconnected the subs, and tried playing the same test tone at the same volume and it wasn't loud? What kind of box? Even a crappy sealed box should get decently loud off two R's on 1kw...

 

[Justyn93 10+ year member]

yeah i wired them like this http://a248.e.akamai.net/pix.crutchfield.com/ca/learningcenter/car/subwoofer_wiring/2DVC_2-ohm_mono.jpg

When i hooked my subs back up i heard what the 50hz at 0 db sounded like it was loud but when i used a CD or my ipod it wasn't near as loud..

 

[Justyn93 10+ year member]

Yup i have them wired at 2 ohms It sounds loud as hell when i use the 50 hz tone but when i turned my ipod on or even a cd i have in my car it was not near as loud

 

[bubbagumper6 5,000+ posts]

I don't know what to tell you man, loud is relative, maybe your expecting too much?

 

[Justyn93 10+ year member]

yeah its wired correctly at 2 ohms the 50hz tone is loud but Cds and ipods are not as loud

 

[FenixAudio 10+ year member]

ddm, isnt goingto help you much with setting a gain. you need an o scope and test tones. a digital o scope is not cheep but its the best way to set a gain. you can actually see the sign wave and watch the amp clip. its awesome.

 

[bubbagumper6 5,000+ posts]

ddm, isnt goingto help you much with setting a gain. you need an o scope and test tones. a digital o scope is not cheep but its the best way to set a gain. you can actually see the sign wave and watch the amp clip. its awesome.

Well it's a hell of a lot better than just arbitrarily setting the gain, and it's a hell of a lot cheaper than buying a scope //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[KyleBechtold 5,000+ posts]

on the alpine h.u I used 9855 I put it at about 9 or so and set the gain. I liked the sound of it better than the h.u all the way up and gain down.. don't ask why it mighta been in my head but...

 

[JimJ 5,000+ posts]

Well it's a hell of a lot better than just arbitrarily setting the gain, and it's a hell of a lot cheaper than buying a scope //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

A DMM will not show you the waveform, and won't help you if your ears can't pick up distortion, either.

Either listen to it, or 'scope it...

 

[T3mpest 10+ year member]

good luck picking up speaker distortion in a car where the panels are vibrating like mad by the time you even begin to stress the woofers. Even under controlled conditions 10% is the accepted figure for subbass distortion. Setting gains isn't rocket science. Turn your hu up until you get to the volume you want, usually around 3/4s to give youself some headroom on lower volume recordings. Turn up the gain until your speaker that should give out first starts to stress or is loud enough, do this with actual music, not a ****ing tone. Move to the next speaker and do the same thing, either until the subs and fronts blend like you want or until you get as much ouput as you can that seems clean without any mechanical noises from the subs. If you hear anything funny or smell it turn it down, stuff rarely blows with no warning signs lol. Now to address why "the tones get loud and music doesn't.

A 0db test tone literally means it's recorded with 0dbs' of headroom. Music gets quieter at some parts and louder at others. A 0db tone means that it's a pure tone recorded to playback as loud as it possibly could be played. Most music on average is about 6db's off that mark, some parts a bit quieter, some a bit louder. 6db's if equivant to 1/4 the power. If your amp can put out and is putting out rms on a 0db tone it's only putting out about 1/4 of that on most music. You just turned a 1000 watt amp into a 250 watter. To simulate actual music, use a -6db tone. If stuff starts to distort or a song seems much louder than most of the other ones, turn the HU down to compensate...... If your really scared that your an idiot and can't turn the knob to the left sometimes too, then use a -3 tone.

If you have a 1000 watt rated sub of high quality that usually means it can handle a 1000 watt amp thermally for an hour or two with no issues, usually indefinetly as the coil can keep up with heat transfer. Using a 0db tone your never seeing that amount of power from the amp, your underusing the sub and the amp. Clipping for a split second won't hurt the sub or the amp, it's always about power under the curve. Heck, AES power ratings (the industry standard) require you to use pink noise with a 6db crest factor. Again 6db's because music goes up and down. Then during this 2hour test, they have to burst the speaker with 4x that rated power for a very short period of time. So a speaker that can handle 500 watts according to AES can take 500 watts continously with bursts of 2000 thrown in every 15 minutes or so. (might be 30 I honestly don't remember lol)

 

[Justyn93 10+ year member]

OKay so i set it to a tone of -3 db and the gain is about 75% and the the boost is almost all the way up i used my DDM with the boost set like that and when i played some songs that hit pretty hard it smelled kind of tangy if i smelt around the port. Does that mean its burning up or is it because they are kind of new(15-25Hrs or listening)

 

[bubbagumper6 5,000+ posts]

A DMM will not show you the waveform, and won't help you if your ears can't pick up distortion, either.
Either listen to it, or 'scope it...

I never said it would. But for the bajillion noobs out there who have no idea what distortion sounds like, what do you think they're going to do, spend a couple hundred bucks on a scope or just set the gain at "3/4" and call it done? Setting it with a DMM may not be the best way, but it's the best way to do it cheap and prevent damage to your equipment.

 

[FenixAudio 10+ year member]

I never said it would. But for the bajillion noobs out there who have no idea what distortion sounds like, what do you think they're going to do, spend a couple hundred bucks on a scope or just set the gain at "3/4" and call it done? Setting it with a DMM may not be the best way, but it's the best way to do it cheap and prevent damage to your equipment.

dmm arent really reliable for test output rails dude. it cant keep up with the transistors switching that fast. it will give you a reading but mabye not the right one. and you do know that th output on the amp is actually ac current right? im not trying to slam you or call you out or anything. mabye call a local shop and ask them to set the gain for you with there o scope. if they dont have one call around until you find one that does. it will only cost a couple bucks and you will know its done right.

also, if your panels are distorting the imaging that bad then you my friend need some second skin or dynamat or anything. something to stop that. the smell your getting is the voice coil heating up. its normal during the break in period. once you set the gain for the break in period you might want to revisit the tuning and check the amp again to see if its perfect again. buying an o scope is a worth while investment. and they always re sell for a good price.

 

[bubbagumper6 5,000+ posts]

dmm arent really reliable for test output rails dude. it cant keep up with the transistors switching that fast. it will give you a reading but mabye not the right one. and you do know that th output on the amp is actually ac current right? im not trying to slam you or call you out or anything. mabye call a local shop and ask them to set the gain for you with there o scope. if they dont have one call around until you find one that does. it will only cost a couple bucks and you will know its done right.
also, if your panels are distorting the imaging that bad then you my friend need some second skin or dynamat or anything. something to stop that. the smell your getting is the voice coil heating up. its normal during the break in period. once you set the gain for the break in period you might want to revisit the tuning and check the amp again to see if its perfect again. buying an o scope is a worth while investment. and they always re sell for a good price.

lol, what do you mean the output is AC Current? With current comes voltage, you use the DMM to measure the voltage. Voltage = sqrt(rms*impedance). It may not be entirely accurate because of box rise, but it's as close as your going to get without a scope. I understand your not trying to "slam" me, but you need to understand this is my method, it's been the common method since I got into this hobby and is generally accepted by most vets as the best way to set them without a scope (provided you can't hear distortion).

Besides, even JL approves, lol. JL Audio - Car Audio Systems

 

[FenixAudio 10+ year member]

lol, what do you mean the output is AC Current? With current comes voltage, you use the DMM to measure the voltage. Voltage = sqrt(rms*impedance). It may not be entirely accurate because of box rise, but it's as close as your going to get without a scope. I understand your not trying to "slam" me, but you need to understand this is my method, it's been the common method since I got into this hobby and is generally accepted by most vets as the best way to set them without a scope (provided you can't hear distortion).
Besides, even JL approves, lol. JL Audio - Car Audio Systems

how do i explain, ac current means it switches back and forth between + and - with the same amplitude and period depending on the input signal. all im say is if you test it with dc its wrong. the amps puts out ac to the speakers thats all. you can do it your way if you like. i bought an oscope for $400 that has a meter built into it and i love it. it helps me test alts. using the hall effect clamps its so worth it. just a suggestion dude.