Dissatisfied with Alpine Amps

arrow12/monkeysan:  I've decided to completely redo the wiring when I deaden the doors.  It may not help, but since it's obvious that the original installer took quite a few short cuts, it can't hurt either.

dwarren:  Yeah, it probably is a case of user error.  I'm pretty comfortable with using the multimeter method for setting gains.   As far as all the speakers being in phase is concerned, I checked the wiring everywhere but behind the head unit where the speaker wires running from the amp are spliced into the factory wiring.  I don't believe there's a phase problem, but if there is, I'll find it when I rewire the car.   In the meantime, I'll try your suggestion for setting the crossovers.   I also may take it to a pro if all else fails.

dzelaya: With the exception of the Alpine amp, I do feel pretty good about the equipment I have.   The amp is probably fine, but I won't know for sure until I either get to the point where I'm happy with the overall sound or I try another amp, whichever comes first.

occurial:  I tried using the amp's crossovers, but the overall sound of the system seemed to improve considerably when I switched them off and used the head unit's crossovers.  (Even when using the same crossover points and slopes.)  The head unit has two sound adjustment modes.  The Normal Mode only allows you a single crossover point with a 12 db slope.  The Pro Mode allows multiple crossover points and slopes but won't allow you to crossover the front speakers below 200hz.  It's one of the few common complaints that Eclipse owners have about the deck.

Sedate:  The components in the front are the JL Audio VR650-CSi and coaxials in the rear are the JL Audio VR650-CXi.  I knew someone would call me on not being more specific about what I don't like about the overall sound of the system, but I'm not sure that I have enough first hand experience to specifically indentify it or put it into words.  I'll give it a shot though.

I'm having a lot of trouble with the high frequencies.  With most of the settings I've tried, they sound hollow and unnatural as though they're playing louder than the other frequencies.  However, when I turn down the tweets (using the 0db, -1.5db, or -3db switch on the crossover) or try to lower the highs with the EQ, the music loses some life and sounds flat.

In the mid range, I can't seem to get the clarity I had before.   With my original setup, the instruments were very distinct.  I could easily pick up and follow an individual keyboard line or base line throughout a given song.  With my current setup, it takes a lot more effort.

In the low range, the bass notes don't sound like notes.  If I turn down the speakers and just listen to what's coming out of the sub, it seems like I 'm just hearing a jumble of low frequencies.   Not only that, but it plays VERY low.   With my headunit's volume turned up to 65 or 70 out of 80 and the front and rear speakers turned all the way down, I could barely hear the subwoffer output while driving home this evening.   Based on what I've read (and heard) in other systems, that's doesn't seem right.  Shouldn't I be able to clearly hear the sub's output under those circumstances?

I'm not sure if that describes what's bothering me about the system or not, but hopefully it's a start. 

Thanks to everyone for your feedback so far.

Whell you did a pretty good job of describing the problems with the sounds. From my experience with the MRV-F450 it was a sweet, powerful amp, even on the sub channel. We had it in our demo car running 2 sets of Type-R components and 2 Type-R 15's wired at the amp to 2 ohm, ,thats right, 2 ohm.  And they HIT HARD!.   One thing I have noticed over the years from alpine amps is that the gains do need to be high for them to work good.

As for the crossover settings, usually I use only one crossover process, either the deck or the sub, but not both, the crossover slope becomes too sharp when you use both head unit and amp, especially when the speakers have their own x-overs also.  When running component sets I generally set the head unit, or amp x-overs to about 65-70hz so they definately cut out the lows but give the speaker a broad enough signal for their x-overs to do their job properly. 

After all that is squared away and polarity is double checked, keep your door panels off so you have access to the speaker crossovers and play around with all the settings. You may find that you will want the drivers side tweeter to be about 1 db less than the passengers tweeter.

Good luck

sedate wrote: First off, let me compliment you on the flawless spelling and gramatical construction of your post. Clearly, an educated man. I think I can work with ya.

Thanks, Sedate.  I try! 

No, I don't hear any actual distortion, at least not that I'm aware of.  I still have a relatively untrained set of ears when it comes to car audio though.

Fire away!

Wow, I can't believe you were able to push two sets of components and two 15's with the MRV-F450!

If I can't effectively push one 10' with it (even at 4 ohms), then there must be something wrong.  I've checked all of the wiring to the sub before, but I'll check it again.  When I check the output at the speaker terminals on the amp with a multimeter, I have no problem getting 28.3 volts, so I don't think there's anything mechanically wrong with the amp.

I know the amp doesn't claim to be 2 ohm stable, so how were you able to run a 2 ohm load into the subchannel?   Obviously it worked for you, but can I do it without damaging the amp or the sub?

The only problem there is that the Eclipse 8553 has 8 volt preouts.  Granted, you have to be at full volume to get the 8 volts and the voltage isn't linear with the volume level, but I still have to be careful.  I'm guessing that even at 75% of the HUs volume (60 out of 80), I'm still getting between 2 volts and 4 volts of input from the HU.

I'll give that a try along with the other suggestions I've gotten.   Any idea why the HP filters on the MRV-F450 seem to color the sound so much?  The issues could be elsewhere in my system, but as I mentioned before, I seem to get much better sound if I use the HU's filters instead of the amp's.

I've tried that, but then I start running into some staging issues.

One thing I did notice after working with the system last night when following the suggestion to tune one set of speakers at a time is that both the tweeters and the rear coaxials overpower the woffers up front.  It becomes even more pronounced when driving.  Hopefully deadening the doors and getting a good tight fit with the MDF spacers will help with that.

Can that Alpine amp take an 8 volt input?  It might be way to high for it.  That could lead to major problems.  Ok just found something.  Read the thing below.  It's direct from Alpine's website.  At the bottom I bolded and underlined a very important thing I think.  If the amp is only capable of taking up to a 4 volt input, then 8 volts is way too muchfor it.

I was concerned about that initially, but the HU only puts out 8 volts at full volume, and the relationship between the volume and output voltage isn't linear.

Here's how I set my gains using a multimeter.  I'll use the front channels (which power the VR650 components) as an example.

The front channels of the amp put out 50W RMS and the resistance of the speakers is 4 ohms.   So I take the square root of 200 (50 x 4) and I should get a reading of 14.1 volts from each set of the front channel's speaker terminals when measuring the output with a mulitmeter.

So I disconnected all of the speakers from the amp, put the HU at 75% volume (60 out of 80) and played a 1,000hz test tone with a 0db reference.   I touched the leads of the multimeter to the speaker terminals and turned up the gain until I got a reading of 14.1 volts.   I ended up just over the 2v sensitivity setting on the amp.

I've tried different methods and settings (including turning the gains all the way down) and I can tell you that I get the best overall sound from the system using this method to set the gains.

So either I'm only getting around 2 volts of output from the HU at 75% volume, the input sensitivity on the amp is way off, or the amp is struggling to produce the kind of power it should be producing given the input voltage it's receiving from the HU.

What I should probably do is measure the output voltage from the HU's RCA cables and see what's actually going into the amp.