i just recently bought a new sound system. got 2x Alpine type-r 12" subs and a v12 mrd-m1005 mono-block amp. their in a separated ported dual 12" sub box. atm it sounds really terrible. heaps of distortion. not sure how to tune it. anyone got the know-how?
Cheers
Craig

a common problem its seems younger generations have is they spend way to much money on the sub and tend to forget the rest now i believe 2x 12" type r's are to big and to much

now a possible problem here is u could have the sound up to high the boxes the subs are mounting in might be cheap (no boxed sub ever really sound good unless done really well) the audio ur playing may be crap quality now a type R 12" is a dual voice 8ohm sub (not monoblock material) should be running on high level 2CH amps with the wires in parallel to get the proper 8ohm

u may need a sub volume switch (is basically a variable resistor)
its possible the RCA cable running to your amps is crap (always buy good cables)

headunits can usually tune the audio to some level depends on what brand and how much uve spent

As for the tuning part, what he said.

I used to set everything to the middle, or low, and play around to see what happens (slowly!) I figured it all out myself after asking 3 people about it and getting varying info.

as Lowlane7 said...you're 18 and telling a 20 year old about younger generations? WTF?

First of all. Alpine Type-Rs (Assuming SWR-1242D is the model) are 4 Ohm dual voice coils. Run at 8 Ohm if the coils are wired in series. Wired in parallel will give you 2 Ohm. Since there are 2 subs that means running the dual coils in series and then run both subs in parallel giving you 4 Ohm. Running everything in parallel will give you 1 Ohm overall...but make sure your amp can run at 1 Ohm.

Secondly, 8 Ohm resistance isn't necessarily multiple channel amp aplpication. Actually car stereo speakers rarely come in 8 Ohm speakers and most common amplifiers come with 4 Ohm application.

Thirdly, subs aren't too big...if they were too big there shouldn't be too much distortion.

Fourthly, I agree with a tune...but how you go about it is a different story.

Assuming you have tuned your speakers already. Turn the gain on the monoblock to the lowest setting. Set your headunit equalizer to "FLAT" or "NORMAL"...on the Pioneer head units that just means the equalizer bars are even/flat but midway up the scale. Disable the front and rear speakers if you can...I just unplugged the RCAs to my 4 channel. Turn the headunit volume to max and play a song that has variable bass (prefer THX Bass Tester or something) from quality recording (preferably original CD). As the tune plays, raise the gain on your monoblock until you hear distortion and then cut back a bit. That way at max volume you won't blow your subs or make it sound ugly. Once you found the sweet spot, replay the song and make sure there is no distortion. Then plug your speakers back in and make sure that the bass isn't overpowering the speakers too much...unless you like that stuff.

If you haven't tuned your speakers...I suggest you do the same as above but set the rears and fronts as separate pairs. Tune the front to be louder for front stage and clarity.

Subs should be playing anything below 100Hz. At <100Hz the bass is not directional which is what you want. You may get away with 150Hz...but I prefer to stick with 100Hz.

Hope that helps a bit.

Are they custom made ported enclosures or something you bought from jb/strathfield/autobarn?
If they're some prefab box, it's highly likely they are not suited to your subs, and will make them sound like crap no matter what settings you change.

im just saying i see loads of people in gen y who are in ya i got a big sub an big amps but have left the rest of there speakers stock or they put in bigger speakers and dont amp them or they amp the bigger speakers with to much power like 30W RMS speakers having 70W RMS in them some even put way to much double ive even seen once a triple the amount on RMS the sub should have in it....if anyone here thinks thats a good idea please explain it to me as i see this alot and i cant explain to them why there audio system sounds crap and tends to catch on fire or explode or blow fuses they just dont listen just like ull find these people usually tend to think fusion is great

ive found my self to be alot more sensible than alot of people in my age group i dont drink i dont gamble i dont have one night stands i own a company i havent found a single person in my age group as sensible as me idk maybe everyone else was dropped on there head at one point or something or im just a boring dull person idk im even more sensible than my parents (dad is having a mid life crisis and is honing around thinking he is a teen atm and mum seems to nag and b**ch alot)

and sorry about the series and parallel mix up my bad

phongus hit tha nail on the head, do as he suggested and you will get it sounding as good as your equipment will sound

I rather sounded aggressive but yes there are handful of younger people who are quiet sensible. I guess I was generalizing. My bad.

Also I forgot to add...what MAD said. Enclosure should be designed to the recommended specificied volume given for best result .

not having a go or anything.

When I was 17-18 I thought I was pretty switched on, heaps of people told me o was very mature for my age etc etc.
I'd step on a limb and say you had a very supported upbringing and this would reflect to your maturity now (and also how you own a business at 18)

I found I had to almost "dumb down" when hanging out with school mates and acted up to seem normal like them.

But my issues came around 20-23 when the older generation wouldn't listen because of my confident mature attitude they assumed I was being C**k (because all young blokes are young dumb an full of cumb regardless aren't they?) and it was frustrating somtimes to keep it short and sweet. (it was punch on time too somtimes lol)

I don't know how to say what I want to say and make sense.

No one will apreciate your maturity more than yourself. So it's somtimes best to keep it to yourself and let people see it through your actions.

Hey Mate,

I dont think the problem is with the AMP or the Sub, your problem is port dimensions. The length of the port on a ported enclosure aswell as the diamter of the port will make a HUGE difference in the sound. What you need to do is find a port size calculator and put in the dimensions of your box. That would be a good place to start.

In my opinion though, your better off sealing up the holes altogether and making them sealed enclusures, the bass will be alot tighter too. Sealed enclosures are alot more forgiving and are far easier to make them sound proper. You can even just wedge a towel in the port for a second and see how it sounds.

Phong knows what he is on about.

hey thanks for all the help guys. had a muck around with it today, couldn't find the bloody equilizer setting on my head-unit. secondly, when i put the gain on the amp right down (i.e. 0.0) it has really bad distortion. as i increase the gain, the distortion dissapears. at the moment i got it running at 0.4 V. also the box i got off a friend. not sure where he got the box from but its about 16-18mm thick mdf, 3"ports and has some sealant stuff all over the edges so seems to be a good quality box i would presume. will tinker around with it some-more tomorrow

From memory, I had my dials set to the middle so that it would make sound, and then I could adjust up or down as needed instead of just going up slowly.

I think I had my gain left in the middle, but every amps ranges vary..

yeah there is no dials on this amp. its all digital. should probably take it right to the top just to find a middle then.

Look into amplifier headroom... It's good to have excess power to avoid running the amp to it's limits which will cause distortion.
http://www.crownaudio.com/amp_htm/amp_i ... _power.htm
http://forum.ecoustics.com/bbs/messages ... 09459.html


And for the original poster, read this: Tutorial - Amplifier Gain & Crossover Adjustment

I'm surprised that no one has told him to try the basic's yet! make sure you have a GOOD ground, if you don't have a good ground tuning goes straight out the window, doesn't matter how good you tune it, it will still distort and sound like crap at high volume. connecting a ground to a bolt on the seat bracket or screwing it into the floor or any where else is NOT a good ground! Do it once and do it right... but I'm sure you knew that lol