Alpine MRD-M301/JL 12W3V2 Tuning Help - diyAudio
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Old 5th May 2008, 10:57 PM   #1
shagone is offline shagone  United States
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Default Alpine MRD-M301/JL 12W3V2 Tuning Help

Hi Guys!,

I'm looking for advice or opinions here.

I drive a BMW E46 328i and i have just temporarily added an alpine MRD-M301 V12 amp with DSP and a JL 12w3v2-D2 in the recommended sealed box. this is a temporary bass solution until i can build my baffle behind the rear seats for my ADS 12" sub to run infinite baffle.

the car came with the factory harmon kardon system but i pulled all of the rear speakers and replaced all of the front speakers. the fronts are ADS 335is 5.25" midbass, 2" tang band mids, 1" soundstream exact tweeters all in the factory locations running from the H/K amp with the factory alpine built cd deck.

for the sub i tapped into the balanced pre-amp signal that was running into the H/K factory amp for the rear channels that i removed. the MRD-301 seems to have no problem directly accepting the balanced signal on it's 8v input setting. the sub is wired for a 4 ohm load and the amp is delivering the optimum power to the sub.

now to the situation! this amp has too many darn settings! has anyone set one of these up in a sedan? i feel like the bass is too boomy and not tight and fast enough for me. i have the sub facing the rear of the car and the ski pass of my trunk removed as well as the empty stock speaker holes for the bass to get through. the amp has time correction, paremetric bass eq, 12/24db selectable freq. sub crossover, 3 levels of bass compensation, selectable phase, gain factor control, selectable subsonic filter.....

the sub has an Fs of 24.3 Hz. and in the sealed box it has an Fc of 47.4 Hz and F3 of 41.3 hz.

i was thinking of running the crossover at 90hz 24db's per octave with the subsonic set at 25 Hz. and a slight bass boost (maybe 4db's) at 40 Hz. and the phase reversed. as far as the time correction, gain factor and the bass compensation i'm not sure yet. maybe this sub is just to boomy for me. I like tight controlled bass with deep extention and a bit of punch. i listen to a bit of everything from rock to rap, regae, even country and jazz. i dont want the sub to overpower the fronts by too much. i know i need to upgrade to 6.5's up front and cut them into the metal on the doors and add a better amp for them. the 5.25's are mounted to the outer door panel now as the factory speakers were but they sound pretty good for now but the up front bass is lacking impact.

Any ideas on settings or am I stuck until i upgrade?

Link to Manual:

http://www.alpine.com.au/downloads/w...1+MRD-M301.pdf
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Old 6th May 2008, 12:06 AM   #2
jol50 is offline jol50  United States
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I have one and was playing with all those settings on the bench. Did you stuff the box? That may help for $2 at walmart. What I would do is set the LP first, I always try 50-70Hz and see what I have. Get it to blend roughly, then work out the rest. With the boost and parametric you have some options, the boost is pretty much the same thing at 40Hz though I like to boost lower than that myself, but not sure your box will do that. I set subsonic low as I can unless I have excursion issues or the enclosure is just never going to get that low (but remember it may get lower than a software curve due to cabin gain) or of course if you are at limits of power from amp then you use more subsonic.

If it is boomy you might run lower LP and let the slope go out longer(12, I always try to for SQ IMO), to cut down the upper bass but still have some. With a tight box I usually go around 50Hz, even though db will drop. With my four 12s IB I am near 35, but I think my other crossover would read higher at same results. When I test the subs vanish at about 60hz and are strongest at 30-35. If you have a peak at say 50-60hz, then use the parametric to cut it down or boost 40 up even with it. Play a test tone CD and see if it is peaking someplace, even when used to listening a peak can throw you off. That is the issue I find most. It may tend to sound good on some music and not others.

The time correction and phase you will just have to play with, they are kind of the same thing anyway right? I have a parametric in my eq and it takes some playing with to get right. I turn the gain all the way up/down and then set the width (starting small) and frequency...then gain it back to blend and have the cut/boost I want. Test tones or music with a bass track that goes up/down is needed. I last used a couple modonna songs that had rising/falling bass tracks. The ones that get up above your crossover point and to 30hz really show best. Or try pink noise.

I would bet you have a peak. You can also dial the crossover down until the peak goes away to find it. If you can get the parametric to work for you, they can do a lot but take some tinkering. I've been waiting to try that amp, just too much other stuff to do and wanted to swap subs first. Does it seem to have some power? I think they are 350@2ohms. I was hoping it would work for 2 efficient low power 15s actually, about 150rms each I think.

I read you can control that amp from the right alpine HU or a controller. That is one thing I like much better is to have that stuff in the driver seat. I don't like amp crossovers and stuff, I like even the amp gains in front. Planning on a new HU but not sure I will like threading menus to find all that stuff instead of simple knobs. I never seem to stop messing with them.
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Old 6th May 2008, 12:17 AM   #3
shagone is offline shagone  United States
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the amp seems to have plenty of power. most measure closer to 400 watts rms at 2 ohms. very effecient too. no light dimming at all without a cap!

i'll try your ideas with the lower low pass at 70hz with a 12db slope. that might reduce the boominess a bit. i'll play wth the subsonic and parametric too. i'm not sure about the time correction though. i may not need it with a single sub?

This setup reminds me of why I prefer either a hatchback or IB subs over boxed subs in the trunk of a solid sedan!
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Old 6th May 2008, 12:21 AM   #4
shagone is offline shagone  United States
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i forgot to mention the box is a pre-fab jl sealed box and it came stuffed with polyfill, and i mean stuffed! maybe i'll try pulling some of the stuffing out and bracing up the box better and re-wiring it with better/thicker cable.

any other ideas?
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Old 6th May 2008, 12:53 AM   #5
jol50 is offline jol50  United States
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I love my IB or a large ported I never have room for. Sealed almost always are lacking bottom for me....and then people tell me IB has no bottom? They are nuts when mine are peaking at 30-35 and I hear 20hz test tone same as a 50. It blows my high side into the weeds as well, it is never lacking for output. I have used phase on ported but rarely do on sealed or IB, I find no advantage to it or its worse. I ran at least 5 12s in a 1.25cf ported and plugged and did not like any. I ran a 10" 4500 mtx in recommended .9cf I think (w/no stuffing even) and it sounded better but had less output, before I got my IB in. Also ran a BP 10 that was so-so. I ran all those on a bridged 2x75 ppi.

I usually end up setting the LP pretty low and pushing up the power for a small sealed, and often stuff it to cut/smooth higher bass a little. I kept the mtx 10 for a spare I was so surprised at the sound, thinking a pair might be a reasonable setup. I always end up running the sub facing back. For the sound I like, pretty smooth with a little kick at 30 or so, I'd guess a LP of 50 maybe higher depending on your mids and how strong the box rolls on up there. If you can get away with lower db slope, it lets a little high bass in to back up mids and blend without being localized if you get it set just right. You might need some 40hz boost if it is lacking there, otherwise use the parametric to cut/boost anything else you need to get it like you want. The parametric will vanish once you get it set right, that is why I crank it when I set parameters of it so I can hear what it is doing.

Removing the stuffing may give it more boom, will give a little more output usually. I don't know, I would think they had it figured out. They are supposed to be good stuff though I have used little of their stuff myself. Just bought a ratty looking jl amp, lol. I also make sure the stuffing does not touch the VC vents, I had some blown kicker boxes that had soot on the stuffing from the VC. Could have been abuse but they need some air if you are going to punish them.

400W, that is cool. I was hoping I could use it, nice size/looks/features. I also have the older style 500w one if I need it but its larger and is in rougher condition. Can't afford the even larger ones, but I stole this m301 was one of my best catches.
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Old 6th May 2008, 02:20 AM   #6
jol50 is offline jol50  United States
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I hope it is not like another sub I have, an explod P5. It gets it on at 45-60Hz and that is about it, in a recommended sealed 1.15cf and I stuffed it good trying to help it. It rocks on bass tracks but music is trying because it has nothing lower or even higher. I can turn the LP to 200Hz and it sounds ok, no boom up at 100hz like most subs. I put a rubicon 302 on it and dialed it up and it got really loud but about drove me nuts too. Louder it got the more one-note it got. I use it for testing amps now. I have a ported alphasonik 10 that sounds good testing, I need to try in car and see but even that takes way more room than four 12s IB. But I'd keep it for another car if I liked it. It gets down to 30 and really rattles things in the house. Or maybe use it on HT if I ever get an amp for that.
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Old 6th May 2008, 04:41 AM   #7
shagone is offline shagone  United States
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the 70hz lp at 12db's helped and a 40hz boost at +4db's. i'll tweak the rest later. i think the sub is starting to break in and loosen up to it is starting to sound better. still not great, but better.
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