2 ch amp help

[Garrett Tait 5]

ive recently upgraded my subs and now i cant hear anything when im full tilt. im going to delete the rear speakers and i was looking for a decent 2 ch amp for my front speakers. im curious to see if you guys have any suggestions for a budget amp that can do ~50-100 rms each @ 2 ohm.

 

i had a few questions also. if the amp had lets say 1% THD would that be noticeable? also how important is the signal to noise ratio? would 80db be really bad? (these are extreme examples)

 

another thing, if the amp is cea compliant does that mean their THD and signal to noise numbers must be true, or is it only hold true to rms ratings?

 

thanks!

[Impious 1,476]

i had a few questions also. if the amp had lets say 1% THD would that be noticeable?

 

No.  Hence the reason it's the standard distortion threshold for power measurements.

 

Also take note that any amplifier is capable of producing more than 1% THD.  1% THD was simply the amount of distortion generated by the amplifier when outputting it's rated power into the specified load.   

 

 

also how important is the signal to noise ratio? would 80db be really bad? (these are extreme examples)

 

It's not.   There are also ways to fudge the number, so unless you know how it was measured it's meaningless.  Any amp of reasonable quality is going to have an inaudible SNR. 

 

Realistically the SNR of the amplifier simply needs to be better than the SNR of the listening environment.  Since we're talking about car audio, it's not uncommon for the environment to have an SNR of 60-70db if not worse.

 

if the amp is cea compliant does that mean their THD and signal to noise numbers must be true, or is it only hold true to rms ratings?

 

IIRC CEA-2006 covered both power (4ohm only) and SNR.  Whether or not they are "true" is still a matter of the manufacturer as there's no authority that verifies the information.  It's still on the honor system.  CEA-2006 requires the amplifier's rated 4ohm power be measured at 1% THD and 14.4V.  Ideally if an amplifier was CEA-2006 compliant then it's rated 4ohm power output and SNR were measured according to the standards specified by the CEA-2006 measurement standards and the ratings accurately reflect that performance.

[Garrett Tait 5]

another question: assuming all filters are clear on my stereo, will the preamp outputs off my rockford sub amp give a full range signal or whats been filtered after the LPF??

[Fi 4 life 0]

What amp is it?

[Impious 1,476]

another question: assuming all filters are clear on my stereo, will the preamp outputs off my rockford sub amp give a full range signal or whats been filtered after the LPF??

Depends on the amp.  You would need to look in the owner's manual to see if it's full range output or filtered.

[Fi 4 life 0]

What is your budget for the 2 ch amp?

[Garrett Tait 5]

t1000-1bd. the all black one.

http://www.sonicelectronix.com/item_17555_Rockford-Fosgate-Power-T1000-1bd-New-Black-Box.html

 

im gonna crack the manual open and read it. im thinking like <200 on the 2 ch but im a tight budget so cheaper will work if the quality is decent.

[Garrett Tait 5]

cant find the owners man for the amp :/  imma look online

[Garrett Tait 5]

okay i posted on the question on the  rockford fosgate fb page and they said it will not filter the signal at all. now all i need is a decent budget 2 ch amp that will put out ~50-100rms @ 2ohm x 2.  level/gain knob would be nice because i cant get a knob for my rockford, all they have is the PEQ which is a bass boost knob, not a gain knob which seems really dumb to me.

 

any suggestions for that 2 ch amp would be greatly appreciated!

[bassahaulic 155]

Why are you looking for a gain control for a highs amp? Wouldn't you just tie it into the radio?

[Garrett Tait 5]

Why are you looking for a gain control for a highs amp? Wouldn't you just tie it into the radio?

the signal is going to be coming out of the 1 rca output, i wont have any volume control separate from the subwoofer, if i turn up the volume on the deck, the sub will get louder and the speakers will get louder. however a certain song might be really loud and i would want to turn down the speakers, but i would be turning the subs down as well. if i lower the subwoofer level (on the deck) , it will lower the volume in the whole car because its dropping the voltage out thru the rca's.

 

basically i'd like to control how loud the speakers will go independently of the subwoofer.

[bassahaulic 155]

Id do that by Y-Splitting the RCA's coming out of the radio. Then send one set to Bass amp with LC-1. And the other set straight to the highs amp.

Edited June 21, 2013 by bassahaulic

[Impious 1,476]

I would agree with bassahaulic.  Put a line level controller in the signal path for the sub amp, not the speaker amp.

 

Also, what HU do you have?  I find it odd you have a sub level control on the HU, which usually means it has atleast 2 sets of preamp outputs, but you want to daisy chain the signal from the sub amp.

[Garrett Tait 5]

kenwood kdc mp145. i called up kenwood and they confirmed it gave off a full range signal.

[Garrett Tait 5]

may run into a problem when the time comes to install. when i turn on the preouts to rear speakers (disabling the subwoofer controlls) the sw level option dissapears and i loose that function. im assuming because the sw level isnt at +15 (on the deck) that the voltage is cut or something). i hope when in preout sw mode that both channels will be active and give a full range signal and not only when on rear mode. if that is the case i guess its time for a new stereo with 2 outputs. then ill have to get another rca cable and ill look into the PAC to control the rca voltage.

[Impious 1,476]

Well, according to the manual you can turn off the lowpass filter in the HU when in SW mode so it might still output a full range signal.  That said the level adjustment would affect both the subs and speakers since you only have the single output, and without knowing much about the level adjustment with a higher setting (like +15) it might cause the unit to reach it's full voltage output at a lower volume setting if it's acting like a boost at that point (i.e. if it outputs full voltage output with the setting at 0 then setting it at +15 would mean you couldn't turn the volume knob up as loud with that setting).  Something to take into consideration.

[Garrett Tait 5]

i know its not a big thing on here but i did get my shit set by a dd1 so the gains are set at that +15 sw level so i know when i hit that volume 25/35 to stop and ill be at the point where the dd1 said there was distortion. i know i know dd1 lets all start a riot lol.

thats why i was hoping for a 2 ch with a knob, so i can have the knob down but turn the volume up on the deck (increasing the bass) then i'll use the knob to bring the volume to where it sounds good. that rockford amp doesnt have a gain control knob, it only has the PEQ which is a bass booster, which is the exact opposite of what im looking for lol.

my main concern is that i thought in subwoofers the signal only came from one of the two rca cables. am i wrong? so in SW mode on the deck, if its only putting out power through (lets say the left) rca cable, when i daisy chain the amps, the right speakers will not work. do you get what im saying?

Edited June 22, 2013 by gt58