LOC gain question

[lakaiguy 0]

I have a tc-loc2 hooked up to a hifonics brx1100.d running at 2 ohms to a re sex v2 12" in a 2 cu ft 32hz box. The amp is rated at 800 rms at 2 ohms and and the sub is rated at 750 rms.

I have the gains on the LOC all the way up and the gains on the amp at about 6/8ths, now that is partly because I set the gains with the remote at 50%.

Anyways is it alright if the amp gains are maxed out because if I turn the loc gains down I will probably have to.

thanks

[95Honda 486]

The gains at any position is absolutely fine...

[lakaiguy 0]

allllright

i've been reading that having the line output converter gains all the way up can introduce distortion

[lithium 358]

depends how they are set with respect to the amp gain. do you hear distortion? if not then its fine. 

[Tenacious 32]

Oscilloscopes are your best friend

[95Honda 486]

^^ No.  Your ears are your best friend...

[lakaiguy 0]

there was a little popping and cracking that appeared to be happening below the subs xmax but close to the rms power

Edited January 1, 2014 by lakaiguy

[95Honda 486]

Just remember, the RMS power has nothing to do with how loud the sub is, how much power it needs or anything else output related, at all...

[Tenacious 32]

^^ No.  Your ears are your best friend...

If you know what you're listening for.. Most people don't, hence why I always recommend an oscilloscope.

[95Honda 486]

The problem is, most people have no idea how to properly use an scope.  If they did, then you would be spot on...

[Tenacious 32]

The problem is, most people have no idea how to properly use an scope.  If they did, then you would be spot on...

Took me 5 minutes to figure out how to use mine.. 

[///M5 2,833]

The problem is, most people have no idea how to properly use an scope.  If they did, then you would be spot on...

Took me 5 minutes to figure out how to use mine..

And if you are at all related to the general public you are still using it wrong. Perhaps you aren't related.

Add to that most O-scopes that people on a car audio forum think are worth buying aren't worth the plastic they were made from and it is even a more off beat recommendation. A little different if you are using a $20k Lacroix of course.

[lakaiguy 0]

Just remember, the RMS power has nothing to do with how loud the sub is, how much power it needs or anything else output related, at all...

sorry can anyone elaborate on this for me, I think I might learn something :-)

[95Honda 486]

The RMS rating is a thermal rating of the voice coil.  That is it.  It has no correlation to absolutely anything else on earth, seriously...

 

Is it a power requirement?  No.

 

Will it tell you how powerful is subwoofer is?  No.

 

Will it tell you how loud a subwoofer will be?  No.

 

Will it tell you an output difference vs. another subwoofer with a different RMS rating?  No.

 

Does it tell you what size amplifier you should run?  No.

 

How useful of a specification is it?  it is the least useful specification given by a manufacturer, behind all other T/S parameters...

[Quentin Jarrell 671]

Just remember, the RMS power has nothing to do with how loud the sub is, how much power it needs or anything else output related, at all...

sorry can anyone elaborate on this for me, I think I might learn something :-)

RMS stands for Root Mean Square. It is the mean average of power in a given set of time. And that is all that applies.

The correct term to give for a thermal rating would be Pmax which is the maximum thermal RMS power that a transducer can handle.

A more appropriate rating to use is Pemax which is the RMS rating needed to hit a targeted Xmax in a given alignment.

RMS just means average. It isn't a "Limit'' of anything.

[Impious 1,476]

RMS power is a misnomer and doesn't actually mean anything. RMS voltage * RMS current = average power, not RMS power.

As for the 'scope thing....No, completely unnecessary and given the variable nature of things still wouldn't be completely accurate. Ears is a much better method, especially since it doesn't give the user a false impression of safety or "perfectness" that people fool themselves into believing they have when they use some tool to set their equipment.

[Quentin Jarrell 671]

RMS power is a misnomer and doesn't actually mean anything. RMS voltage * RMS current = average power, not RMS power.

As for the 'scope thing....No, completely unnecessary and given the variable nature of things still wouldn't be completely accurate. Ears is a much better method, especially since it doesn't give the user a false impression of safety or "perfectness" that people fool themselves into believing they have when they use some tool to set their equipment.

RMS as defined by Theile and Small and used by Klippel is not average voltage x average current. It is the average of the instantaneous power readings gathered by testing. Voltage and current is not gathered averaged then tallied at the end. The instantaneous power is calculated so many times a second and is averaged at the end of the test.

Just taking the average voltage and average current and then multiplying them would not give an accurate account of power. It's an algorithmic expression that incorporates multiple instantaneous power readings over time.

[95Honda 486]

The important thing is that, no matter how we define RMS, it doesn't correlate to anything but a thermal rating of the voice coil...

 

Except in the case of DSS, of course...

[Impious 1,476]

RMS power is a misnomer and doesn't actually mean anything. RMS voltage * RMS current = average power, not RMS power.

As for the 'scope thing....No, completely unnecessary and given the variable nature of things still wouldn't be completely accurate. Ears is a much better method, especially since it doesn't give the user a false impression of safety or "perfectness" that people fool themselves into believing they have when they use some tool to set their equipment.

RMS as defined by Theile and Small and used by Klippel is not average voltage x average current. It is the average of the instantaneous power readings gathered by testing. Voltage and current is not gathered averaged then tallied at the end. The instantaneous power is calculated so many times a second and is averaged at the end of the test.

Just taking the average voltage and average current and then multiplying them would not give an accurate account of power. It's an algorithmic expression that incorporates multiple instantaneous power readings over time.

They may have definitions for RMS power as a matter of convention and so as to express how they are using the term...but the purpose of the RMS calculation is for use with terms that have both positive and negative values. Since power isn't negative (voltage and current are both positive or both negative, multiplying either together always results in a positive power figure), there isn't an RMS calculation for power.....or it would be a meaningless answer if you tried to perform it. I'm no EE, but from everything I've learned from werewolf (an MIT Master Degreed EE), RMS power as an electrical quantity doesn't exist. Average power and instantaneous power, yes. RMS power, no.

There actually is an average voltage and current for a sine wave, Vavg and Iavg, which is not the same as Vrms and Irms which we use in calculating average power. They describe two different things.

[95Honda 486]

The audio community as a whole has embraced RMS as an term for continuous power...  It has stuck one way or another for the wrong reasons...

 

I think you guys are splitting hairs here, we all know it isn't derived correctly.  But, more importantly, to help the masses, we need to make the disconnect where it counts, and that is the incorrect correlation of RMS as a loudspeaker term for anything but a thermal rating...

[Impious 1,476]

The audio community as a whole has embraced RMS as an term for continuous power...  It has stuck one way or another for the wrong reasons...

 

I think you guys are splitting hairs here, we all know it isn't derived correctly.  But, more importantly, to help the masses, we need to make the disconnect where it counts, and that is the incorrect correlation of RMS as a loudspeaker term for anything but a thermal rating...

Agreed. I just find it a little irritating that we as a hobby perpetuate misinformation of basic electrical laws.

[95Honda 486]

Agreed.

[///M5 2,833]

I would vote that the title of this thread get edited.

Because of it I didn't read it. Many others should.

[smashedz28 110]

Should be recreated and pinned. Solid info in here.

[lakaiguy 0]

Haha maybe if this forum saw more traffic, you guys are funny