Need some help

[YK86]

Have a bunch of questions I wanted to ask the stereo guys.

1)I'm going to hook up an amp and sub(s) this week on the Rustang. The first question is, I am going to be using the speaker level inputs on my sub amp (instead of RCAs) but the only lines I can use are ones coming out of the stock amps (the signal coming from the head unit is supposed to be too weak). Seems like this is how all the guys hook up their amps to the Mach 460 stereo BUT my Kenwook amp says to only use a line amplified up to 25W MAX but the line I would be using from the Mach 460 would be 85W MAX, 45W NOM. Will this hurt my amp?? I looked for aftermarket converters but even those say 30W max.

2)The more I measure, the more it looks like I will only be able to put in 10's and still have some trunk space left. I've always like how my 12's hit in the Accord but if I can somehow design a box to fit in the tiny ass trunk, it would only fit one. The box would be sealed, and the amp is a 400W max (2ohms), 300W X1 RMS (2ohms) and 200W X1 RMS (4 ohms). I want hard hitting semi-low bass that shakes the inside of my car (I don't care about bass that wakes up the neighbours anymore). So, which would provide the bass I am looking for with the space I have:one 10, two 10's, or one 12? And what sub would you reccomend? What's a good bang for the buck (somewhere around the $100-$150 range)??? Thanks in advance.

[Bobs89LXi]

Yasu,

As far as your first question is concerned, they do make adjustable level impedence matching transformers. I used one on my old Sony head unit a few years back when I decided to add a couple of Rockford 10's and an amp to my system. The head unit had no RCA pre-amp outputs, so I had to use the transformer, spliced into the rear speaker outputs. It worked well for me.

In answer to the second question, the larger the sub, the lower the resonance frequency. It dopends on the type of music you are listening to. For rock, R&B, etc., the bass is higher, so 10's are the way to go. For techno, 12's usually do the trick. For rap and deep thumping, 12's or 15's will give you the results you need.

[shepherd79]

i had never used the speaker level inputs on my stereo.
May be you should consider getting a new head unit. As far as i know, speaker level inputs won't give you as good sound as preamp RCA outputts. i would recoment getting at least something that has sub preamp outputt.
I am using single Alpine 12" Type S. in my car. it shakes inside of my car great. it is like having live massage in the car while you driving.
i have Blaupunkt Keywest sitting inmy room, it has rear 2V. RCA output. the only problem with it the radio is burn, but it is one section and it is like $60 for the part.
i can sell it to you, make me an offer.
i don't need it. it sits in the box and collecting the dust.

[YK86]

Thanks. I'll have to look around for the transformer. As for adding a new head unit, that is out of the question for this car right now but thanks for the offer. It's too much hassles and money, and the Mach does a very good job for a stock unit (just missing the bass I like). I just don't have time to tear the car apart to do everything like I did in the Accord. I think I will try out two 10's but not too sure what brand to get yet.

[89accordlxi]

Could you please explain why you are using the line level inputs instead of RCA's? 1. Does your amp not have RCA inputs or
2. are you concerned because the head unit doesn't provide RCA outputs??:huh:

If it is 2, just go get a line level converter and switch form speaker level input to RCA's.

The concern with feeding the line level inputs of your amp with 2 much power has to do with noise. I Think if you feed it more than recommended, you will get buzzing or other unwanted noise.

As for a sub, If you liked the way 12s sounded before, then stick with what you know. Just one 12 will give you more then enough bass that you are looking for.
Thanks for providing the specs for your amp. It will help alot with the sub selection. If you want to get the most out of your amp then get a dual 4 ohm voice coil sub. This way you can wire them the voice coils in parallel and give your amp a 2 ohm load to get max wattage from your amp. 300 watts to a single 12, Out of experience, All's I have to say is wow,hold on to your hats!!!:D

Hope this helps.

Peace.

[YK86]

The Mach doesn't have RCA's and my Kenwood sub amp has a built in line converter but it says to only use signals up to 25W so I just wanted to know why it had to be less than 25W and what would happen if I went higher. After going to three of the local stereo places and listening and comparing, I went with two of the new Kicker 10's. The other stuff was either out of my price range or didn't impress me too much.

[damackz]

Good choice! yeah i am looking at the Alpine S type for sure, JL has some awesome subs, one of tha best in tha biz, i love kicker tho! :pimp: tha rustang will be bumpin now lol

[Vanilla Sky]

hook it up straight through, and then take the gain on your stereo for that(those) channel(s) down almost to nothing, and work up bit by bit from there

Derick

[shepherd79]

Originally posted by itch
hook it up straight through, and then take the gain on your stereo for that(those) channel(s) down almost to nothing, and work up bit by bit from there


Yeah, Itch is right, turn your gain all the way down and adjust it slowly.
i don't think you would heart anything.
plus remember that non of the nead units put out 45watts of real power. max 25 watt.
my alpine says 45 per channel but i know i am getting like 20 -25 max.

[damackz]

speaking of which i am looking to get tha new alpine rated at 60W x 40 and i think u actually get that typa wattage as u have to hook it to ur batt like u would a reg amp........ :pimp:

[POS carb]

if the signal coming from your head is too weak then it's probably like a lot of "Premium" sound systems that feed a low level signal to an outboard amp or small individual amps per speaker (Chrysler). Splice some RCA connectors to the wires, I bet u they're line level. If you rig a 45 watt RMS input you'll fry it for sure. Plus you'll get a lot of noise from going from line (head unit) to amplified (Mach 460) back to line (amp input transformer/resistors) and then reamplified (amp output).

Look at the Infinity Basslink sub, it's self-contained with an amp and everything and it's REALLY small, I've never heard it but if space is a big concern go check it out.

[staticpat]

i got a speaker level to line level converter from an audio shop for $20. it basically takes in an audio signal of any level, and converts it to line level (RCA) so the amp gets a nice clean signal. the converter also has gains you can set, so you don't lose signal meant for your other speakers.

you have to splice the wires in the back of the hu meant for your speakers though. just pick a set (i used front). make them so that each wire (l/r + -) splits, one half going to the original location, and the other going to the converter. then just plug some rcas into the other end of the converter.

im sorry i made this sound so difficult, its really not. just go by an audio shop, or radioshack and ask for a speaker(or high) level to line level converter. it will come with instructions.

[YK86]

Thanks guys! I'm going to try and do all this tommorrow. I finally got the dimensions for the boxes so it fits in the trunk the way I want it so I will build that first. I'll try taping the pre-amp Mach lines 1st and see how it works.