Newbie: opinions on planned setup?

[2ManyTickets]

I'm a complete car audio newbie and have some questions that I couldn't really find the answers for in the forum...

I have a 2002 P5. I'm planning on getting an Alpine 4 ch. amp (MRV-F340, 55W x 4) driven off the stock HU. For speakers I'm planning on Infinity Kappas (5x7 x 2 + 6.5 x 2).

Now my questions are: (I'm into good sound quality so the system doesn't have to be awfully loud or anything.)

1) First off, how are the amp and speaker choices for my goals? Overkill? Too cheap? Just right?

2) I'm not using a sub for space and cost concerns. Is this OK keeping in mind that I don't need the system to be loud?

3) Since I'm not using a sub, I'm thinking of using the rear 6.5 speakers to produce much of the bass while keeping the fronts off the bass. Is this how it works? I have this nagging feeling that I would be "wasting" the rear speakers if I only get them to do bass or mid-bass duty. (Again I'm a total newbie and don't really know what I'm talking about.)

4) If in response to question 3 your answer was to use the full range for all four speakers then ignore this question. If you answered that I should send bass to the rears, should I consider some other speakers?


Thanks a lot!

 

[1sty]

1) Great equipment and the amp has speaker level inputs to make the hook up easy. For a newbe you made a great amp choice for your system. the speakers are good stuff too.

2) No sub will mean no sound in the sub bass range, funny how that works . Sub bass is 20-70 hz and is not reproducable by anything but a sub.

3) You can do that with the rears but it would not be worth the extra equipment and of no real advantage. You would need an out board crossover / LOC to do it and again no reason to. Just play the 4 door speakers at 70 hz and up or whatever you rear likes and you'll be good to go.

4) If you were itching to break the bank you could have someone make a rear subwoofer enclosure for a 6.5" sub but nothing else is going to fill in that range of sound other then a sub. Stick to High passing the door speakers and add a esily removable sub box. Thaqt way you just disconnect the subs speaker wires and pull out the box.

 

[2ManyTickets]

Thanks for the detailed reply. (thumb)

Another forum suggested adding midbasses to the rear doors then low pass them. This seems like a good move to me as it will leave the highs in the front while adding some bass without a sub.

Pros/cons? Or should I really add a sub instead? (I would very much prefer not to from a space/complexity/cost point of view.)

 

[1sty]

You can add just a mid bass to the rears but you have no way to lowpass it. The amp cannot be bandpassed. If you were going to use an aftermarket head unit with adjustabel crossovers as the high pass then the amp as the low pass thats doable. However since you were keeping the facotry radio the amp gives you the choice of either HP or LP not both. The only cheap way to do it is to add bass blockers for the HP but at that point why even bother buying decent equipment. They suck!

You could use just a mid from a component set that matches your front coaxles but they will still play high frequencies as the mid naturaly rolls off. The mid will not play the highs as loud as the tweeters as it will be rolling off which may be to your liking. With your setup the only way to not get highs from behind you is to get a componet set of speakers and just not use the tweeter or not put any speakers in the back at all.

You may want to just replace the front speakers with a very good component set and power just them and keep the rears powered by the factory radio. You can replace the rears or keep them stock. That way all your power is dedicated to the front.

You simply can't get sub bass without a sub. Not doable. you can get a component woofer to go low but it can not handle that range of sound accurately as the sub can.

 

[2ManyTickets]

Thanks for your patience in explaning things. But I'm still not too clear on the high-pass low-pass issue (specifically, the inability for the amp to do so) that you stated in your post. I had an impression that the amp in question can do what I needed to (i.e. high pass to front channels and low pass to rear channels). I've attached a small image of the manual... perhaps there's something I'm not understanding.

I suppose I should be looking at subs then. Which size/brand/model would you recommend?

 

[1sty]

The amp can low pass the rears but Lowpass only is for subs not midbasses. Midbasses need a high pass of aout 70hz and a lowpass of about 500 hz. If you have a basic mid doinf only as lowpass it will distort and sound like crap as it can not handle that range of sound.

If you don't want subs then don't get one, start without one. The only reason not to do it this way is if you want a 5 channel amp that will have all 4 door speakers and the sub channels in one amp. alpine make a great one, MRV-F450. Gives you 50x4 and 200x1 for the sub.

I would hold off on anything until you have had a chance to listen to a few different setups and determine if you tastes demand a sub.

 

[chuyler1]

Many people say they don't need a sub cause they don't listen to music loud. However, most people, at one point or another drive down the highway with their windows open. No stock stereo, or even aftermarket midbass can keep up with the sound of wind rushing in the windows.

My suggestion is to buy a nice set of speakers or components for the front, and a 6.5" or 8" subwoofer in a small enclosure. Powering a small sub off the rear channels of that amp bridged will give you enough sound to keep you happy, and it will make your new front speakers sound that much better. You can still have rear speakers powered by the stock head unit and they will sound fine.

You can put quick disconnects on the subwoofer box so you can take it out if necessary.

Another option could be a prefab enclosure that fits under the passenger seat such as the one made by Clarion. I don't know if it will fit under our seats though.

 

[koolracer]

What is the model number of the Clarion Sub you are referring to?

 

[chuyler1]

Its the SRV303 7" 120W Amplified Subwoofer
http://www.clarion.com/marine/marine14.htm
(don't ask me why its located under marine)

I saw one on ebay for like $120, but the MSRP is like $300. I don't know if dealers still carry them.

 

[2ManyTickets]

Alright, I've spent the last few days in auto sound stores listening to those Infinity's and bass is somewhat lacking. It's adequate, but I can imagine it falling short once in a moving car with wind/road noise. I'm going to go with you guys' suggestion and go with a sub. I will amp the front Infinity's, leave the rear speakers stock and run those from the stock HU, then run a sub off the rear channels of the amp bridged. Questions:

1) Any obvious flaws in this setup? Or is this fine?

2) Sub size and brand/model recommendations?

 

[1sty]

JL 10W0 or 12W0

 

[chuyler1]

Ditto on the JL 10W0, there is no entry-level sub that will perform so well with only 130watts. The W0 has been the best low-power sub on the market for years, and nothing comes close because other companies are more focused on high power subs.

The only other sub I'd recommend would be the Image Dynamics ID10, but even that is rated for 175watts.

 

[joshua69247]

If you are trying to save space and are willing to spend a little extra $. You might want to look into a setup like this.
http://www.jlaudio.com/tutorials/isobarik/index.html
It's called isobarick loading. It allows you to put two subs in one box and get them to work as one speaker.
I used to have 2 8's in separate boxes, I needed more space in my trunk, so I went with the clam shell design.
It sounded just as good if not better then my previous setup. I also setup my brothers stereo the same way. He has 2 10 Infinity reference subs. They are loud as hell, and saved him a lot of space.
The only problem with this is that it obviously requires you buying
1. another sub
2. another amp (You'll need to run this in mono, stereo wont work, and it will need to be stable at 2 ohms.)
3. Also, the wiring is a little different.
Personal I'm a SQ man, so I'd want all the frequencies playing on all 4 front speakers and a sub for the bass in the rear.
This sounds kind of like what your looking for, clearly your not a SPL freak, otherwise you wouldn't care about space. Fill it with 8 15's and call it a day.
If you decide to go this way, and need any help, just pm me. I'm more then happy to answer any questions.

 

[chuyler1]

I don't see how an isobaric enclosure solves any of his problems.

The enclosure will take up more space than with a single 8" or 10" (because one sub will stick out), it requires more power, but you don't get more surface area. This box design was good back when subwoofers didn't have strong enough motors to pump out low bass. Times have changed.

Its a waist of money IMO.

 

[1sty]

Agreed, big waste of money!

You need twice the power, twice the subwoofers to obtain the same DB. Also it doesn't save much space becuse you have a 4.5" subwoofer sticking out of the box.

If you want to fit 30 8" subs in a camaro thats when Isobaric becomes useful oters there is no point.

 

[2ManyTickets]

Thanks for the info people.

I've heard a lot of good things about 10W0's. I've also heard them in the local auto sound shop and they are awesome. JL 10W0 it is then. Now more questions:

1) Where is a good place to get them online?

2) Pointers or resources on box-building? Or should I buy a pre-fab? (I'm OK with making things outta wood. )

 

[1sty]

No where. There ar no authorized internet retailers for JL.

You can buy them in a box from JL for short money.$169 retail for the 10W0 in a sealed box.