Amp ratings...

[pimpnyou204 10+ year member]

Why would companies rate their amps at different test tones. Like I see why certain companies might do theirs in order to inflate theirs but known quality companies like arc audio I seen rate their input voltage 4v at a 1k hz tone 0db. From my understanding lower frequencies require more power to reproduce and when u set your gains it's to 40 no?

Also a side question. I know many amps don't have a 8v input gain as do very few hu but if u have a hu with say 8 and a amp with 4 do u just assume 4v is at half volume and set gains to that? All assuming that your hu will NOT clip at full volume.

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[goingdef 10+ year member]

According to the birthsheet to my power series RF amp it has a graphed chart showing the output from 20hz all the way to 20k but like you guessed it makes the most power at 1k and loses about25w at the extreme of each end, as for the other question I would still use a dmm to set the amp instead of going on the input levels and splitting up the dial like a clock even the settings indicator(listed input levels) on my amps are close but not dead on!

 

[pimpnyou204 10+ year member]

I still use my dmm but setting with a dmm can still be bad.

Like for instance a dmm only measures power being out putted.. Not if it is being distorted or clipped at a certain frequency. Like on a high voltage hu u can go to like 1/4 up then turn your amps all the way up and get the desired ac volt but it being clipped to hell or with tons of noise in it.

Is there a way to test what volts are coming thru your preouts with a dmm?

 

[pimpnyou204 10+ year member]

Bump for help lol

 

[BnGRacing 10+ year member]

Why would companies rate their amps at different test tones. Like I see why certain companies might do theirs in order to inflate theirs but known quality companies like arc audio I seen rate their input voltage 4v at a 1k hz tone 0db. From my understanding lower frequencies require more power to reproduce and when u set your gains it's to 40 no?
Also a side question. I know many amps don't have a 8v input gain as do very few hu but if u have a hu with say 8 and a amp with 4 do u just assume 4v is at half volume and set gains to that? All assuming that your hu will NOT clip at full volume.

Companies advertise different ratings b/c of 'monkey see...monkey do'

There is no enforceable standard in car audio when it comes to rating anything. So when company X starts rating their amps with only 1 channel being driven @ 1kHz, Company A will have to either offer a similar test result or rate their equipment more conservatively. Rating a car amplifier in the mid-band isn't anything new, they used to do it that way in the 80's. Its just now people are infatuated with getting the most 'watts' out of whatever they're purchasing. It's all marketing driven...nothing more. Since everyone rates their stuff differently you're effectively comparing apples and oranges when you spec shop. I don't like CEA ratings either...mostly the A-weighted THD+noise figure that's taken at 1w is my beef. The game changes when you up the power and turn on the amp's processing.

In the heyday of car audio (late 90's) it wasn't uncommon for amps to be severely under rated and to have distortion numbers in the 0.00X% range. That will not sell amps today b/c people, generally, are ignorant to the point where they think a 200w 6.5" co-ax speaker will be louder and sound better than a 100w speaker just because it has a bigger number on its sticker. Same thing goes for amps.

Ask anyone who has owned an old school 500w amp and a new

There's more to audio than ratings and things you can read on a spec sheet.

 

[pimpnyou204 10+ year member]

I can see that and the ks 300.4 definately sounds way better than my saz 100.4, circles actually. But my question is how do te people with 8v - 5v decks work out the issue with a lot of sq amps only having like 4v inputs. Do u just go up to the 4v on the hu and set the amp to 4v and call it head room?

 

[BnGRacing 10+ year member]

Pre-out voltages go up exponentially; so your 8v HU at 1/2 volume will be much lower than 4v...wouldn't be surprised if it's 1v.

Most higher end SQ amps really don't care how much input voltage they see and you'll never run into the issue of clipping their input stages. What that means, in a nutshell, is that if the gain is set all the way down and the amp still clips; you're clipping the input. A high quality amp shouldn't have an issue. Hell, I've used 20 year old amps with high voltage pre-out decks without issues and those amps were supposed to have 1v max input.

 

[pimpnyou204 10+ year member]

So I should be ok running my eclipse avn 726e at pretty much 77ish volume (80) and worry about clipping the arc audio ks 300.4 (4v.)

I've read in a review, their site, and then a tech person that this unit will not clip at full volume and give a full 5v at max only. Any way to test this?

 

[TheUnderFighter 10+ year member]

Another thing, I know a lot of multi-channel amps rate at 1khz because they are full range amps and they play those tones so those ratings are relevant. What good does the rating for your speaker amp do if it's rated at 80hz? Whereas, mono amps, will be rated at those lower frequencies, cus that's where they are used.