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Critique my sound system...

4K views 59 replies 13 participants last post by  footheter 
#1 ·
So right now I'm piecing a sound system together and think I'm headed in the right direction but really have no clue since I'm new to the stereo gig. Here is what I have so far and what I plan on getting. I'm really just wondering how all of this will go together :D

Head unit: Pioneer DEH-4500MP (or was it 4600MP?)
Speakers: Polk DB650 6.5's all around
Sub: JL 12W3D4 (not installed yet)

For the amp I was just going to go cheap and get a Diesel audio 175Wx4ch amp for 100 bucks or so from Fry's. Bridge 2 channels to the sub (350 watts) and the other 2 channels to the 2 rear speakers (175 each). Unfortunately they are sold out on those so I might have to go another route.

As for the sub box, I'm not sure what to do. I've found some cheap sealed boxes on ebay that are the right cu. ft. for my sub (about 1.25 cu. ft.) and am a little weary of the quality but don't want to spend a bunch of money. Here is what I found...any experience with this stuff?

http://cgi.ebay.com/ws/eBayISAPI.dl...MEWA:IT&viewitem=&item=300114674638&rd=1&rd=1

I'm really just looking for some better sound. I don't really listen to music loud unless it sounds good. Just recently I fixed the fucked up job Circuit City did putting my speakers in with some nice adapters that utilized all the screw holes :rolleyes: After installing those, it sounds MUCH better than before but I think it can be better with a little thump :D

Anyway, no more rambling. Let me know what you think :D Thanks
 
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#2 ·
Brain,

If you still are interested, my offer for the sub box still stands on the table. Just pay for materials and a little extra for me and my buddy to make it and carpet it.

175 per speaker sounds a little steep. I would double check the specs on the speaker.
 
#6 ·
Brain -

Do you have a standard cab or an extended cab? If you have an extended cab its possible to cut out the rear storage cubbies and build sealed boxes in the walls for subs. I have 2 - MTX 8" subs mounted in the walls, and they don't take up any cab space. The won't win any competitions, but personally I like the tighter bass of smaller subs anyway, and they hit pretty hard for what they are. Here is a pic:



I also saw a mention of an in cab cage, so that might complicate things because you'd have to be able to get the rear panels out to build the boxes....

Also, I have the Pioneer DEH-P8600MP and I'm very happy with it. The only complaint is that when it gets hot the CD transport acts up sometimes.

More pics of my system here:

http://s63.photobucket.com/albums/h154/bradleyem/Stereo System/
 
#7 ·
Be careful with wiring a 4 channel amp. You mention bridging 2 channels to get 350 watts out of the Diesel amp. Note, this is stable at 4-Ohm and not 2-Ohm. If you have a Dual 4-Ohm sub, you can wire it to be either 2-Ohm or 8-Ohm. You would need either a Dual 2-Ohm sub or a Single 4-Ohm sub to safely get the maximum out of the amp without clipping it.

Also, cheaper amps normally do not put out their specified wattage. I would recommend running front and rear speakers off the headunit and buying an amp dedicated for your sub.

Other than that, it will sound decent for the money. Pioneer and Polk make decent products.
 
#8 ·
I have an extended cab and I took out the rear platform since the rear seats would've been deemed useless with the cage anyway. I'd like to put subs where the stock speakers go but I like having 4 speakers since sometimes I run without doors.

I think I'm going to go forward with having a box made. I think I'm going to make some angle iron brackets coming off the cage to hold the box in one spot and I can bolt it down fairly easily. I'll also be able to make the sub down-firing so it doesn't sound like the sub is pointing in anyones general direction.

Phill, I don't think I want a huge box that'll take up the entire back. I really just want something with enough air space in a very simple box (probably totally square or rectangular) for easy mounting to the cage. Maybe I'll even make my own if I go that simple :D Now if only I could figure out the dimensions of the box I need...
 
#12 ·
OK I found out the sub I have is a dual 4ohm sub. JL recommends a 250 RMS wattage for the sub, would I be best off finding a 1 channel 4ohm amp that puts out 250-350 watts? I know some amps don't like running at 2ohm.

Someone teach me! LOL :D
 
#13 ·
Get a mono amplifier. Some hae two speaker outs so you can run both coil's at 4-ohms with out a problem. Mono's also sound a lot better with subs because it limit's the frequencies to the sub unlike a stereo amplifier. I used to have a 4 channel stereo amp that I bridged to run two subs and when I went to the mono amp I saw a world of difference.

Check Ebay for some good deals and if you can wait - just make sure it's not refurbished.
 
#19 ·
So what would you recommend for an amp? I saw this amp on Crutchfield. Looks to be pretty good with the 3 year warranty :) Rated at 310w at 4ohms.

http://www.crutchfield.com/S-Jy1HWn5HcQK/cgi-bin/ProdView.asp?g=120&I=489AP1000M
That is a great amp for the $s. It's rated at 500 watts at 2 ohms, thats the load a dual 4 ohm sub presents when wired in parellel (both positives and both negatives run to the pos and neg terminals on the amp).

I have a buddy who is running Profile amps he bought 2 years ago as refurbs, they sound really good and are easy on the budget. Just remember that a Profile amp (or any low cost) will probably put out right at or a little less than rated power, while a more expensive amp might make more than it's rating.
 
#18 ·
If you want a cleam sounding sub, buy amps by going off the THD rating.

This is how much distortion there is at 1 decible. For instance, a THD rating of .01% would yield to 1% distortion at 100 decibles.


The lower the THD, the cleaner your sub sounds (or speakers)
 
#26 ·
Profile isn't a bad amp for the OP's price range. It will put out its rated power and do a good job at it. I would also recommend buying an amp from an authorized retailer and not from eBay or some random car audio site. This way you get the manufacturer warranty with the product. Most car audio sites are not an authorized retailer so you are always taking a chance if something goes wrong. I've learned my lesson in the past.

And for what it is worth, MTX makes a decent amp. It does not put out "way higher" than their listed RMS.

Also, I would recommend this amp wiring kit. I am running the 1/0 Gauge version of it in my car.
http://www.knukonceptz.com/productDetail.cfm?prodID=KOL-AK4
 
#29 ·
Lots of information between you two duking it out :D

Anyway, I checked out the Profile audio site posted above and saw a CA600M amp for 70 bucks. To tell you the truth, I still don't even know what I'm looking for as far as amp ratings and such for my sub. I've decided to go with a Profile amp of some sort, I just don't have a clue as to what will sound best while keeping the amp cool. I mean, should I be looking at ratings for 2ohm amps or 4ohm amps? I have no clue really...
 
#33 ·
Hope I wasn't too much of a distraction, I really was (and still am!) trying to provide some helpful info. Here is a site

http://www.bcae1.com/

that can answer just about any question you could have about car audio. It's a little dry, but as far as I can tell all the info is solid. You're doing it the right way, spend some time and learn before you buy stuff and you'll get much better sound for your money. I've heard systems with $450 dollars total (sub included) in speakers and amps that sounded absolutely amazing, and I've heard systems with $2k in speakers and amps that were pretty weak.

What kind of music do you listen to, and how loud? Are you looking for quality (clean, clear accurate reproduction of music) or quantity (loud bass that shakes other cars near you)?
 
#30 · (Edited)
If you look at the following page, it shows you how to wire a Dual 4-Ohm sub. You will wire the voice coils in parallel to achieve 2-Ohms.
http://mobile.jlaudio.com/support_pages.php?page_id=161

This means you will want to purchase a mono channel amp (because they are stable down to 2-Ohms) and will look for the ratings at 2-Ohms. Does this make sense?

EDIT: The Profile amp you originally posted from Crutchfield would be a great fit. More than enough power and a true manufacturer warranty. Excluding the brand name, do the specs seem like a match to everybody else?
 
#36 ·
I just went on the Profile Car Audio site and they have a 400MSX model amp rated at 300w at 2ohm. Looks to be perfect with what I want in an amp. The THD is around .07% so that's pretty good. Also comes with a 1 year warranty and it's only 50 bucks. I think when I get paid I'll go ahead and pick that up!
 
#38 · (Edited)
If you're using head unit power on the rest of the speakers the 400MSX will be great. Or you could use a 2 channel 400SX for the front pair of speakers, head unit power for the rear pair (or just forget the rear pair altogether is what I'd do) and a 600M for the sub. That would have your amps at $115+ shipping and you'd have enough power to never have to push your amps hard at all. If you're not already familiar with crossovers read the sections on bcae about crossovers so you get everything set up right.

Those Polk 650s are a really nice sounding speaker BTW. Very smooth tweeter and great midbass.

Norcals idea for blocking the amps up is a really good one. My sub amp gets pretty hot, and its tight to the carpet. More airflows gotta help, so I guess my interior's coming apart again...

edit: a single 12" sub in a good box is perfect, IMO. You'll have enough bass to sound great without pushing the sub to its limits. A sealed box will sound really tight and punchy, and if you decide you want more thump just build a good ported box. Porting can really get a lot more output from a sub, but the box has to be built correctly or it'll sound like crap.
 
#44 · (Edited)
Here is a good site for figuring port size and length, box volume and tuning frequency

http://www.the12volt.com/caraudio/boxcalcs.asp

the only thing I couldn't find there is a calculator for multiple port lengths and tunings. The box I built for my d-cab was a bit small according to the manuf specs, so I got it close and used the port calculators to get the port length right.

Here's another port calc site

http://www.carstereo.com/help2/Articles.cfm?id=31

I'd shoot for a 30-35hz tuning freq
 
#50 ·
The more I think about it I don't think I want just a square box. I was going to setup the sub box right in front of the passenger rear speaker but now I don't like that idea so much because it'll block the sound coming out of the speaker in the back. Now I'm thinking about having a box directly in the middle between the 2 seats but in the back and have the sub downfiring so it doesn't get pointed in a general direction. Only thing I have to figure out now is how much room I have between the seats when they are reclined all the way :D This project will turn out to be more fun than I thought :)
 
#52 ·
Brain,

I specced it out. Kinda worked with it:

2.2 cubic feet
27.71 hz (tuned to)

To get to 27.17, your ports will be either:
(2) 2"X8.36" long
or
(2) 2.5"X13.5" long

If you have the room, go with the bigger pipe. Will sound the same, but you wont hear as much port noise.


Note that JL claims 1.75 tuned to 30.3. This is a SQEAK louder, but my setup will play the lower notes cleaner. It also has a smoother curve.
 
#54 ·
#57 ·
Do you have any idea what you are talking about???

That JL only needs about 300 Watts. Any more and you are only going to get a couple more decibles out of it (if that) and a higher risk of damaging the sub. If you run 850 watts through it, you are asking for premature failure.
 
#58 · (Edited)
i like kicker stilwater has been around for ever....I have 2 cvr dv10s, and kickers all around in the door, kicks ass, 2 3 channel kicker amps, with 2 mono channels for my subs, and 4 channels for my highs, box behind the seat facing the floor using the center hump as a spacer from the floor, noone sits in the back of my truck cept for my daughter in her car seat, so i dont need floor room yet.:)

Head unit is pioneer DEH-P80MP with sirius satelite.

Dont listen to people who think you need to buy high end stuff to sound good, it all depends on how you piece it together. Match everything up right and you can build a low budget system that sounds great, its all in matching components up right, and biggest thing for bass is in the box, has to be made right.

I get alot of stuff wholesale so i got a sweet deal on all my stuff.
 
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