sub problem

I have installed a 15"sub(SWR-1541D Alpine) and mono amp(MRD-M300 Alpine).I set up amplifier the way Alpine recomends(from Alpine's site PDF file"Maximize the output of your MRD-M300/MRD-M500")
and now even at low volume it seems that it's playing with "distortion".I know that Alpine recomends MRD-M500 amp instead of MRD-M300 but i cant through many awayi have already bought MRD-M300.I don't know what's wrong.May be you guys know any different settings for this amp.or something else what could be a problem or may be ....i don't know what to think of.I checked all wires....they seem all right..i do not know what to think of.May be something wrong with a sub or amp????????They both new.Any ideas plz...
Thank you

Do you have any X overs? Are you using a stock or aftermarket head? Also what kind of enclosure and what's the volume?

The head unit is a Sony CDX-M730 , no X overs( i am runing another amp for my components and 6 x 9 (MRV-F340 Alpine amp 4ch),enclosure is sealed volume is 1.4-1.45 cu.ft
Are you using a stock or aftermarket head? i do not know how to answer this because i do not understand the difference betwen stock and aftermarket.......sory.
i only can listen musik at low volume to get clear base but 15" sub must hold 500 RMS and 1500 peak my amp only 200 RMS   everything is new HU amps and sub and speakers
is it enough info ....if not ask something else plz

Stock means that you have the original factory radio that came with the car. Aftermarket means that you have upgraded to a better head unit such as you have done. As far as the distortion goes hard to figure out with out seeing you car. But you might want to check your ground. Were did you ground your amp? Is it grounded to clean bare metal? Also on the MRD-M300 what size power and ground cables do you have? Also I know the bass is distorted but is it loud? Let me know all this so I can try to further assist you.

The graund is on a clean metal ,the wires on a MRD-M300 is 8gauge(Both the same ground and power and separate power wires to amps) ,the bass is loud but distorted but not loud "to become a deaf" but i am 99% sure that this amp and sub could play much better
The car is a new 2002 A-Class 170 CDI mercedes and distortion is from a sub not from a car parts.Once again thank you very much bberman1 for your help i hope eventualy we find the course of this problem

try turning the gains down on the amp...the amp could be working too hard and throwing out distortion like mad, thus creating your problem...

sometimes "optimum" isnt what is really optimum for your setup...there is no magical way to do one thing that makes it perfect in all situations...

Might want to change out the RCA cable and see what happens. It could also be the enclosure might want to try a 2.5 cu/ft enclosure the larger the enclosure the cleaner it will sound.

correct bberman, and the less power it takes as well...when you make an enclosure larger, you decrease the subs power handling capabilities...

Roman I have plenty of experience in this and have had cars with the same problem as you because of bad grounds. So when you say "distortion is from a sub not from a car parts." That’s not true If have a crappy ground connection. Then your amp will not be getting the clean power it should thus creating distortion. So yes car parts do have to do with distortion.

I forget to mention that i had enclosure 1.8 before..and believe me it was absolutely no changes but 2.5 it's too big fo my little mercthe gain switch is on 12 ( it has 18,12,6 and 0 db adjustments..... so how you can see the amp is not working too hard)
Low pass filter is on 80 Hz,
Subsonic filter is on 25 Hz,
Parametric Eq is on 50 Hz,
Width is 1,
Level is 10 db,
Bass compensation is on "on"
maybe this settings no good ? Any suggestions on a different setup?
Does someone know where i can learn about frequency because i do not understand them for example in the set up file it says:"Warning: Since it is possible to overlap the subsonic
and low-pass filters, you may create a condition where amp will produce little or no output. Make
sure that the subsonic filter frequency is significantly lower than the low-pass filter frequency,
unless you have a very specific performance goal in mind".I understand what they meen but i am not very clear about it or another example:"Set the width (Q) to affect the desired frequency range around the center frequency. For
example, if you would like to boost frequencies between 45-75Hz, the bandwidth is 30Hz, which
corresponds to Q=2 if the center frequency is 60Hz. Just keep in mind that higher Q is more
narrow, and lower Q is wider. If an overall subwoofer level increase is required, it is advised to set
the P.EQ to its widest setting (Q=1 for M300, Q = 0.5 for M500).
4-4 Adjust the level as needed for either boost or cut. Please note that it may be necessary to go
back and re-adjust other settings such as input level at this point, depending on your tuning goal."I want to learn about overlaping,boost or cut e.t.c......and sory for my bad english
RCA's goldplated and quite thick.....
maybe this Alpine's sub not good enough?I did not hear it anywhere to compare .At low volume it's quite good
Does someone know how can this sub play?
Thank you again.

Hi bberman1:
The car parts ....i ment plastik parts which can shake and make noises.But about ground.i think is good i have sanded surfase and made hole ,put a screw and nut.Is it good?But i am not sure about case that i put both amp's grond cables in the same hole..can i do that?
Thank you

That sub can have a volume of 1.3FT^3 - 2.5 FT^3 Now turn off the subsonic filter. If it doesn’t have an off switch then turn it to the highest frequency you can and let me know how it sounds.

Normally you don’t have any problems sharing ground points but every once in a while you get engine noise but not necessarily distortion. However you might want to ground your sub amp separately and see what happens.

Hi bberman1.I did turn off the subsonic filter it's still cant hold enoug power.May be i want too much?Can you this warning from a alpine setup?
"Warning: Since it is possible to overlap the subsonic
and low-pass filters, you may create a condition where amp will produce little or no output. Make
sure that the subsonic filter frequency is significantly lower than the low-pass filter frequency,
unless you have a very specific performance goal in mind"

Any ideas how much power it can handl?
Thank you

Can you explain this warning

What it means is if the subsonic filter and the low pass filter are set at the same frequency. They will cancel each other out leaving little frequency to amplify. Thus putting out very little sound.

I think that's what hapenning with my amp"They will cancel each other out leaving little frequency to amplify. Thus putting out very little sound"

What to do is set the subsonic filter as low as it will go say 15 or 25 Hz what ever the lowest is. Then turn the lowpass up as far as it will go say 250 or 500HZ see if it sounds better.

If i put 200 Hz which is the highest it's worse.So i tried put lower till 50 Hz and its better but not any louderI do not know what to do...Confused

What do you have the subsonic filter set at?

Subsonic filter set at 25 Hz

Low pass filter is on 80 Hz,
Subsonic filter is on 25 Hz,
Parametric Eq is on 50 Hz,
Width is 1,
Level is 10 db,

Low pass filter is on 80 Hz,
Subsonic filter is on 25 Hz,
Parametric Eq is on 50 Hz,
Width is 1,
Level is 10 db, this settings were before now

Low pass filter is on 50 Hz,
Subsonic filter is on 25 Hz,
Parametric Eq is on 50 Hz,
Width is 1,
Level is 10 db,

Set everything as high as it will go except for the subsonic filter leave it at 25 HZ. I am going to get the manual for your amp so I can better understand you amps features. Also what time is it over there?

I correct my self turn off everything (subsonic, bass correction, parametric etc) only leave on the LPF (Low pass filter) and set it to 200 and listen to it. Then set the LPF to 100 and let me know what happens>

try turning the parametric EQ off, turning the Low Pass Filter up to 85 or 90Hz and turning the Subsonic filter completely off...

put one of the bassiest songs that you listen to into your deck, and turn the volume to 3/4...go back to your amp while the song is playing and play with the gains, starting at 0 and working your way up until you hear a little distortion...once you hear distortion, turn the amp gain down a bit and see what happens...that should be close to optimum settings for your amp...

after you have this set, you could start to play with the subsonic filter and the parametric EQ, but without a good understanding of how the parametric EQ works, its a pain in the ass to play around with...you may also want to play with the low pass filter setting a bit too, if that is too high for the music that you listen to...but your ear will tell you far more than I can sitting at my computer as far as what will sound good and what wont...

sory bberman1 can we continue tmorrow because it's 23:08 outside?
Thank you

Not a problem

Hi again.I tried to turn all filters off exept Low pass filter and then i am getting different soun which i do not like.So i thinki had CD with too much bass that's why i was getting too much distortion but now i think alpine's sub can't kick hard enough!May be i shoud put some stuffings inside????????
May be ported box???????
I do not know but i am still going to find any shop (Alpine one)and listen the same sub may be nothing wrong with it?
What are you thinking guys about changing boxes?And any ideas on this sub how it can kick?
Thank you

Where can i learn something so as i could understand EQ and all frequencies?
Thank you

My friend I will be out of the office today so I will be unable to help you till later on this evening. As far as any web sites that teach you about EQ's I don’t know of any. But if you search the web im sure you will find something. Also I would try to play with the amp and im sure you will be able to achieve the sound you desire. First I would try and leave the high pass at 80 and turn the subsonic to 25 while leaving everything else off. Now with those at 80&25 adjust the input level like the instructions say. Doing that should make things sound right.

Thank you
I will be trying......

Roman any luck?

Hi.I think it's a little bit better thank you.I am thinking of putting polyfill inside the box or may be even change it to prted one?May be smaller box? Any ideas? Will i gain anything ?
Thank you

And i forgot something else.Bberman1 do you have heard this sub?How hard can it hit?
Thank you

I think I may see the problem here - Turn the Gain (Level) on the parametric eq all the way down. Often if you push a low eq hard at all it will distort. See if the helps. Also, here's a site that will exp0lain quite a bit ot you on EQ's and prequencies (and anything else you'd like to know)
https://www.eatel.net/~amptech/elecdisc/caraudio.htm


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/NyxBass

Thank you NyxBass.I will try.
This site .....i know about it, it's not enough info there.Very shot notes.i need something moore in detailes.