alpines playing quite??

[brafferty]

so for my install i through some polk MM 6501's in the front, and they sound amazing off this amp, but as for the backs which are my alpines (SPR 60c). they play around a 1/4 as loud as my fronts. i know that they have different impedence, but i feel like there shouldnt be such a big difference between 150 rms and 110 rms. Here are some factors im curious is this is the cause

1. There is a big air gap between my panel and the speaker, making it not properly enclosed, so i know they wont be as loud, but im not sure how big of a factor that would be

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[wew lad 5,000+ posts]

they can still get loud if there's air leaks, you just wont get the same bass response. i guess technically you could lose some overall response but i doubt itd be 1/4 as loud.

i think you may just have a difference in speaker sensitivity, do you have a tweeter setting on those passive crossovers? I know my polks do, may just need to level match the back with the front.

just checked the specs, theres definitely a sensitivity difference between the two. the alpines are listed as 88db and the polks as 94db. that's a huge difference, 10db is said to be twice as loud, so we're talking about the polks being about 50% louder at the same power

heres a great article i found that explains what im trying to say in detail:

Guide to Speaker Specifications - PSB Speakers

 

[brafferty]

sorry i couldnt finish my original post i had an emergency and hit post, but i see what you are saying, and yes there was a tweeter level on these crossovers (both polk and alpine), is there a way i can give the backs more power? if that makes sense. Its so much quiter than the polks and it irritates me to have my doors open and have the backs completly over powered, another issue i thought it might be is the hook up of wires, they have 2 inputes on these aplines. I didnt think itd matter which set i put one each (one to the amp, one to the tweeter crossover)

 

[wew lad 5,000+ posts]

you can have the gain set higher in the rear than the front, but then you'd likely sacrifice front output because you don't want to just turn the rear up and put the amp into clipping. I would try setting the tweeter attenuation on the polks in the front to -3db and see if that makes any difference. The other thing you can do is use your fader on your headunit which will reduce either the front or rear output RCAs depending on how you have your system set up. Keep in mind you want most of the sound in front of you, so make sure to not set the rear speakers louder than the front.

 

[brafferty]

you can have the gain set higher in the rear than the front, but then you'd likely sacrifice front output because you don't want to just turn the rear up and put the amp into clipping. I would try setting the tweeter attenuation on the polks in the front to -3db and see if that makes any difference. The other thing you can do is use your fader on your headunit which will reduce either the front or rear output RCAs depending on how you have your system set up. Keep in mind you want most of the sound in front of you, so make sure to not set the rear speakers louder than the front.

the polks are fine though, its the alpines that are having troubles, what would dropping the tweets in the front effect the back? ive played with the fader on the HU but they are literally super quite, id record a vid but i dont think thatd help,ill see if turning the gains up might help, but maybe it was just a bad speaker choice to match these polks, polks are perfect, loud, clear, alpines are quite to where i cant even say more about them because i cant hear the full potential at all

 

[fly_marlin]

I don't think the speakers have different impedance - they have different thermal ratings. What are the gains set to for the rear channels that run the alpines? Try switching the RCAs on the B2 - switch ch1/2 with ch3/4 and see if there backs are now louder.

 

[brafferty]

I don't think the speakers have different impedance - they have different thermal ratings. What are the gains set to for the rear channels that run the alpines? Try switching the RCAs on the B2 - switch ch1/2 with ch3/4 and see if there backs are now louder.

sorry i just saw this was replied on haha, the gain is turned up a bit more than the fronts and that didnt help, i hadnt thought about switching the RCAs though

EDIT: the impedence on the alpines are 4, and the polks are 2.6

 

[wew lad 5,000+ posts]

yes the polk mm6501 uses a 2.7 ohm coil instead of the normal 4 or 2 ohm. due to this the polks will pull more power. dont just turn up the gain on the rear, thatll just clip your rear speakers if you go past whatever your input signal uses...

you want more sound from the front than the back, and as i explained already the reason why you get more from the front is speaker sensitivity. if swapping the RCAs doesn't change anything then this is the answer, if swappings the RCAs makes a difference (it shouldnt) then there's something wrong and you need to post back here with more information

 

[brafferty]

Sounds perfect haha, i wish would have though about that before hand though ;(