lavamadness

Here's what I've got:
Kenwood CD player, 50x4
Stock 4x6s up front.
Apline 6x9s in back.
2 10" Alpine Type S subs
Sealed, single chamber box, approx 2 cu ft.
Apline 300W (200W RMS) mono amp.

I've played around with trying to tune it, and I can get one type of music to sound nice (r&b/pop) with some punch, but then other types (rap or rock) sound horrible.

I know I need to replace my front speakers, but I want to work with what I've got at the moment. Because as it is, I was happier when I had a crappy Koss base tube in the back.

What I'm basically looking for is to be able to listen to different types of music and having it sound pretty decent with some nice bass. With what I have, it seems if I want them to sound decent, it's like not having subs at all.

Any ideas?

napalmdemos

I had the same problem. What I did was set the memory on my cd player (mine gives you six slots) for whatever music I was in the mood for. Most cd players have some kind of built in EQ/bassboost or level crontrol built in them and some have a memory to save them in. I do admit this is a pain in the A$$ but if you dont have these options you will just have to adjust it every time.
Now for you amp you may need to adjust your gain every time also adjust your crossover levels you could be pushing to much bass and its giving you distortion when you crank it up.

Are you useing the amp to power just your subs or everything?

lavamadness

I'm just trying to figure out if that's all it is. It'd be nice to be able to set the amp so it makes most types of music sound "okay". (I understand that doing that won't make things sound "best".) But when I try that, there's just not much punch in things at all.

When I had the base tube, it wasn't as night and day between types of music, so I'm wondering if it is just tuning or if there is something wrong with the setup itself, box too big/small, not enough power, etc etc.

89blackGTA

Are your subs single or dual voice coil? What ohm are the voice coils? you might not be pushing that much power to the subs. i know those amps are not 1 ohm stable. So if you are running it at 4ohm then you are only getting about 125rms to both subs.

Brian

9177

What size of wire do you have for your amp? You should have atleast 8 gauge. Also are you sure you have your box sealed very good? If all checks out ok you might need some more power.

lavamadness

I'm not sure if they are dual-voice coil subs or not. I'll check that out when I get home. They are running in parallel though. If they are dual-voice... what'll that do concerning the amp?

Not sure what gauge wire I'm using either.

Any tricks to I check how well the box is sealed? I took it to a local audio shop to build the box. They have a good reputation, so I didn't think anything of it. But then, I had assumed they would let me know if I was doing something wrong with the system I was putting in too. *shrug*

Jim85IROC

iTrader: (2)

Quite often, people have such a miss-match of gains and bass boost controls, that their bass winds up sounding horrible.

Sometimes it's a good idea just to set everything flat, and take the time to properly set your gains. Then get the best sound possible by playing with crossover frequencies. Once that's set, move on to some minor EQ adjustments.

lavamadness

I'll play around with the tuning as you said Jim. Gains first, then crossover, then EQ right? What's the best way to adjust each? Just until it sounds the best?

Also, I found out the subs I have have dual 4-ohm voice coils. (And they are connected in parallel.) The power wire to my amp is only 10-gauge.

Jim85IROC

iTrader: (2)

That's the general procedure to follow. With enough practice you can tell what it needs (in most cases) by ear, so you can avoid all that crap, but once it gets too far out of whack, even a pro is going to just reset everything and start over. The problem is that people hook things up, and levels aren't matched properly. Dial in a little bass boost to compensate, then play with the other 20 adjustments, and the next thing you know it sounds like *** and you can't figure out why.

set everything flat on your head unit, and make sure the loudness is turned off, and any sort of sound enhancing crap (like BBE) is turned off also.

To set your gain, start with your sub amp. Disconnect the other amp so that all you hear is the bass. Turn the gain all the way down. Keep turning up the head unit until you start to hear some distortion. Turn it back down a tad. Now keep turing up the gain on the amp until you hear distortion. Turn it back down a tad, then just a little bit more for good measure. Keep in mind that distortion in bass is VERY hard to hear, so you're better off erring on the side of safety unless you want to start blowing stuff up. Anyway, now turn everything down and power the amp for your highs back up. Listen at whatever level you're comfortable listening at, and bring the amp gain up until your highs are at the same level as your bass. This is your first adjustment that will effect your sound quality. If your 2 amps aren't pumping out sounds at equal volumes, you'll never get a smooth response to work from. Anyway, once you've got them matched to a point that's suitable, turn it up until you hear distortion again. If you find that your highs are distorting first, you've got to turn back the gains of both amps until the distortion in the highs disappears.

So anyway, now you need to listen at a couple different levels. Unfortunately, using 2 different size amps for bass & highs results in a problem with linearity, meaning as you turn it up, the relative volume between the amps can change. This means that if you have it set to sound even at low volumes, at high volumes your bass will be louder than the highs. There isn't much you can do about this unless you want to use another sub amp to run your highs. This is just one of those things where you've got to set it at the volumes that you think you'll have it set at most often.

Anyway... once your gains are done, you can play with your crossover. With your typical thirdgen install, this just winds up being a comprimise no matter what you do. Generally you don't want your subs to play much over 80hz. The problem is, the 4x6s in your dash aren't worth a crap under 150hz or so. If you've got 6x9s in the back, you can raise their level to help with the 80-150 range, but then it kills your imaging. It's a balancing act, and it's more or less up to you experiment and see what works best for you. I don't run rear speakers, so although that helps my imaging, it kills my frequency response. I wind up with a pretty big gap between the top end of my sub frequencies and the low end of my dash frequencies. Anyway, as you fool around with your crossover frequencies, you'll have to make minor adjustments to your gains to keep everything sounding good.

Once that crap is all set properly, it should sound pretty good, or at least as good as your speakers are going to sound. Other than a mild bump in bass and/or treble from your head unit, you're not going to be able to change the sound much.

lavamadness

Thanks for the info Jim! Will try setting it up again in the next few days.

I was still wondering about the subs and my amp. From what I've gathered, 2 dual 4-ohm voice coil subs connected in parallel will cause the amp to see only a 1-ohm load right? How bad is it for the amp or my speakers running like that?

lavamadness

Was going over my options regarding the load on my amp, here's what I came up with:

1. Disconnect one of the subs. Load = 4 ohms.
2. Disconnect one voice coil on each sub. Load = 2 ohms. (Can you hook up only one VC on DVC subs? Or is that a bad idea?)
3. Get a newer 2 channel amp, connect 1 sub/channel.. Load = 2 ohms per channel.
4. Get an amp that is 1 ohm stable. (I'm guessing this is the more expensive solution?)

I'm still curious as to what running my amp with just a 1ohm load is doing to it or my speakers.

Jim85IROC

iTrader: (2)

You don't want to run just one coil on a DVC sub. It completely changes the t/s parameters of the sub. If your amp is able to play into 4 ohms bridged, series-wire the two coils on each sub. This gives you a single 8 ohm load for each sub. Then you can parallel the two subs, which will result in a combined 4 ohm load, which your amp will work fine with.

Jim85IROC

iTrader: (2)

It's damaging the amp. Think of an amp like a power supply, and your speaker is the device that's drawing the power. The lower your impedance is, the closer you are to a direct short. 1 ohm is almost the equivalent to a direct short. With such a low resistance, your amp is trying to supply vastly more power than it can safely deliver. If you turn it up too far, you'll exceed the abilities of the amp and it'll shut itself down if it's got that type of circuitry, or it'll just overheat and smoke itself. Even if you play it at safer volumes, the extra strain on the amp is going to drastically shorten its life span.

lavamadness

I'll play around with stuff this Sat and see how it all turns out.

One last thing... would it be better to have both subs hooked up at 150W RMS, or would it be better to just use one at the moment and get 200W from the amp?

Jim85IROC

iTrader: (2)

?

You have a mono amp. That mono amp should have absolutely NO problems pushing a single 4 ohm load (both subs). In theory, if you used 1 sub, you could have a 2 ohm impedance, which would cause the amp to produce twice as much power.

In terms of SPL, it should be a wash. Just keep both subs in there and wire them properly. Removing one won't provide any benefit.

lavamadness

Oh, I wasn't worried about the amp handling the power. I was just wondering which would sound better, two subs at 150W, or one sub at 200W.

Thanks for your help Jim.

lavamadness

Set everything flat and started from scratch. Sounds much better now. The subs were hooked up properly in the first place, so it's all good there.

Thanks everyone!