Do Alpine amps work well in X5 or go JL?

btrvalik · #1 10-29-2005, 08:55 AM

I think I've read here that the electrical system of the X5 can be a little noisy due to all the computers etc. I think alpine should well since they make good gear and are often an OEM supplier to BMW. I'm planning to use the Alpine mrp-m350 mono amp to drive a sub. I'm also considering a JL Audio 250/1 but I'm not sure the extra cost is worth it. I've seen lots of good reviews for the Alpine on many car audio sites. The JL is twice the price and is probably a better piece overall...but it may be overkill for my needs. I'm not going to be driving it that hard. Anyone have experience with this amp in their X?

el_duderino · #2 10-29-2005, 11:54 AM

What sub are you thinking of using?

The noise is usually not an issue with sub amps... the darned subs won't play RPM-related noises since they won't move fast enough, the buggers: )

Alpine amps are by far the best of the "head-unit" brands for amplifiers. Their newer models are funny-lloking (to some), hard to adjust due to adjustment location, and kinda big, so not too many I know have a lot of experience with them. The one thing I would say is that all Class D amps generate some FM interference. The JL seems least likely to jam yourFM based on experience on other cars, but the Alpine shouldn't be a problem either.

I don't neccesarily think the JL is one ofthe best-SOUNDING amps out there... but I think it's very well built, reliable, and with its regulated power supply it is a consistent performer (the Alpine will put out more power while you are accelerating due to the slightly higher alternaor output, so your amp sounds worse when you slow down.)

I don' think you'll screw up either way, but make sure that someone knows that the amp you get won'tjam your FM, or make sure you have an exchange path when you buy it.

btrvalik · #3 10-29-2005, 12:46 PM

I'm on the process of getting a stock sub box. While the stock box may not be as stout as a custom box, it should be good enough for me. If I lived up near you.. I would have had you do one for me. With a little modification I think I can put in 2 JL 6W0 and if not I will select a 8" unit. I didn't have the box yet so I'm not sure of the internal volume. I'll measure it once I get it and then figure out which way to go with woofers. Any advice is welcome.

el_duderino · #4 10-30-2005, 12:03 AM

I doubt you can get two JL 6 in there (holes are too cloe together), and I doubt it will sound good if you do.

I suspect an 8" is much better...but I'm ify on the whole refacing scheme.

Where are you geographically?

btrvalik · #5 10-30-2005, 09:16 AM

I think you are right on the holes being too close together. And the box may not have enough volume to support them either. If the box is big enough I could always cut/grind away the speaker frame in the overlapping area where the circles meet. Depending on box volume I may just use a single 8".. I think it is big enough for that.. I'll know once I measure it. Do you have a recommendation for a 8" sub? I was thinking of going with JL but perhaps there is a better choice? I live in the Boston Area... custom sub up here was 1600-1800 installed. Seemed rather steep for my needs.

alpac · #6 10-30-2005, 11:14 PM

Quote:

Originally Posted by btrvalik

I think you are right on the holes being too close together. And the box may not have enough volume to support them either. If the box is big enough I could always cut/grind away the speaker frame in the overlapping area where the circles meet. Depending on box volume I may just use a single 8".. I think it is big enough for that.. I'll know once I measure it. Do you have a recommendation for a 8" sub? I was thinking of going with JL but perhaps there is a better choice? I live in the Boston Area... custom sub up here was 1600-1800 installed. Seemed rather steep for my needs.

Not sure why you do not want to go for a 10" rather than 8" if you have to cut the box anyway

. A 10" fits and renders well as I explained in one of my posts and you will have less openings to close. If you use a 8" not only you will get less bass but you will have a lot more opening to seal

. A 10" almost cover the two 6" holes if you do it right.... but it is your choice and your X5 budy!

...just my 2 cents

dkl · #7 10-30-2005, 03:21 PM

Quote:

Originally Posted by btrvalik

I think I've read here that the electrical system of the X5 can be a little noisy due to all the computers etc. I think alpine should well since they make good gear and are often an OEM supplier to BMW. I'm planning to use the Alpine mrp-m350 mono amp to drive a sub. I'm also considering a JL Audio 250/1 but I'm not sure the extra cost is worth it. I've seen lots of good reviews for the Alpine on many car audio sites. The JL is twice the price and is probably a better piece overall...but it may be overkill for my needs. I'm not going to be driving it that hard. Anyone have experience with this amp in their X?

I have that exact Alpine MRP-M350 amp driving a JL Audio 10W3v2 sub in my X for a little over a year now. No problem at all whatsoever. Heck...the amp barely gets warm...even after 6 straight hours of usage! But then again, I don't really push it that hard...so it's good enough for my application. The only complain I have with the MRP-M350 is the lack of a remote control for bass adjustment. Other than that, I love the little sucker

btrvalik · #8 10-30-2005, 06:28 PM

cool.. sound like I can order my amp!.. should get the sub box next week.. then select a woofer... and install.. winter is coming up here ... no time to waste.

btrvalik · #9 10-31-2005, 08:20 AM

I'm trying to get very high quality bass and that my come at the cost of quantity. It has less to do with cutting a 10" hole and more to do with the amount of air the box contains. This trapped air acts as a spring when the woofer moves and must be matched to a given woofer. If the box is too big or too small you may get the wrong sound. It's not only the woofers size that comes into play but it is also stuff like the motor structure and suspension materials. I will use a 10" if the box is large enough to meet the Theil-small parameters for a good 10". My understanding is that the box is somewhere around .3 ^3 ft. If that is the case, I have not seen a 10" that will work well in that small of a box. Once I get the sub the first thing I'm going to do is measure (by filling with water) the actual volume of the box. I'll then find the biggest woofer that will work according to the thiel-small equations. At the end of the day.. making bass is all about physics... and a simple equation will predict how it will sound. Sometimes tial and error will work.. I've had best luck following the math.

alpac · #10 10-31-2005, 10:44 AM

Quote:

Originally Posted by btrvalik

I'm trying to get very high quality bass and that my come at the cost of quantity. It has less to do with cutting a 10" hole and more to do with the amount of air the box contains. This trapped air acts as a spring when the woofer moves and must be matched to a given woofer. If the box is too big or too small you may get the wrong sound. It's not only the woofers size that comes into play but it is also stuff like the motor structure and suspension materials. I will use a 10" if the box is large enough to meet the Theil-small parameters for a good 10". My understanding is that the box is somewhere around .3 ^3 ft. If that is the case, I have not seen a 10" that will work well in that small of a box. Once I get the sub the first thing I'm going to do is measure (by filling with water) the actual volume of the box. I'll then find the biggest woofer that will work according to the thiel-small equations. At the end of the day.. making bass is all about physics... and a simple equation will predict how it will sound. Sometimes tial and error will work.. I've had best luck following the math.

FYI I tried an 8" in the same box and it did not perform as well as the 10". The stock enclure is actually pretty big. It goes well under the cargo floor. Math and theory are all good but sometime practical experience is not bad either. That is what models are for. I started by building my own box using volume and size guidances for a 8" sub. The result was pretty good but I was not quite pleased with the way it fit in the cargo space. It did not have the stock look I was looking for. I then tried the 8" in the stock enclosure and the result was not better than with my own box but it had a better look. Then I studied how to fit a 10" which I eventualy did and the bass was significantly better than with the 8".