MJHSC400

If that sub is a monoblock then no-- if it's a 2ch which I don't think it is, you would need to bridge it-- as indicated on the amp-- but I think it's a monoblock-- so it should be hooked up correctly--

Power from your battery and whether the car is running will affect the total output, as well as how much signal the amp is getting-- this alone is a huge contributor--

You want to be sure your amp is getting plenty of preamp voltage, and with a cheap line level converter you just can't always be sure it is-- Unless it's top notch equipment--

A better way to be sure that it's clean and solid signal would be to run a line driver on the low level signals to the factory sub amp--

I use an audiocontrol 2xs for this which works great as a noise isolator as well as a solid 9v rms line driver-- This will be SURE your amp gets PLENTY of preamp voltage--

Setting the gain like that video honestly doesn't tell you if you have a clipped signal or not-- It just tells you total output-- so I'd still recommend having someone that knows what to look for do it for you for $10~ $20 -- Good insurance against smoking a coil -- reading total output just doesn't tell you enough information-- Without actually bench testing that amp you've got first you can't be sure what it's actual output is unless you've got a birthsheet with it from an actual bench test done at the factory before shipment.....

You could download some tone sweeps if you want to try it and set the gain where it's just pulled back where you start to hear distortion at MAX listening volume-- or the loudest you'll ever play it-- where there's hopefully no distortion present-- You just want to listen for a choppy signal thru the sub vs a very accurate and clean tone -- And if you're still not sure, just let someone do it -- you did the expensive part afterall-- it's worth it-

You should still be able to get a bit more out of it with a good CLEAN line driver like I mentioned--

Don't buy a cheap one or you'll regret you did-- they will induct noise, work poorly, etc...

I got the 2xs in mint condition for $25 on ebay-- if you find one or an EQL either would be awesome --

MJHSC400

A good way to determine where the gain needs to be set is to play that 50hz tone, and measure the voltage at the rca output of the line converter--

Do this test while the volume **** is turned to about 2:30 or 3 o clock-- or about the loudest you'll ever listen to it-- Have your bass set to 0, mid set to 0 also on the head unit--

This will let you know for sure that your voltage is matching up-- but you can still do a little tweaking by ear to fine tune it-- though sometimes that fine tuning is better done while playing music--

Try to match the gain setting on the amp to the voltage level you're getting at the line converter output-- (rca level voltage) --

I've always done this by ear though if I were competing I'd use an o-scope to be sure nothing is clipping whatsoever--

labtec

I have no problem with taking it to a shop...I might just end up doing that. One thing I don't understand is I wired the woofer both ways:



After playing a 50Hz tone, all I got was a 45 (450watts) reading on both (gain was turned up all the way). Putting all number readings aside, I think I should be able to tell a noticeable difference between the two wiring configurations. Am I overlooking something with the amp settings??

MJHSC400

I'm just wondering if you're doing these tests with the vehicle running or off?? The alternator provides a solid 100A and about 15v that will drastically improve amp power over a cold battery by itself-- it's a whole extra source of power you may be overlooking-- like a power generator if you will--

wiring--
so the dual 4 ohm sub should be wired like so-- (to achieve the 2 ohm load [or 1.5 if you like the way it sounds better])

amp positive to coil 1 AND coil 2 positive --

amp negative to coil 1 AND coil 2 negative --


Signal problems/solutions--
My next consideration BEFORE you take it to a shop and get fed some sort of string of bs in order to sell you something or possibly a whole LOT of somethings-- try to find a line driver -- many companies make little 2 way electronic xovers that double as line drivers -- kicker makes a 7v or 9v line driver / 2 way xover for about $45 and it's worth a shot-- it will guarantee that your not feeding your amp distorted signal from the factory sub amp that is notorious for going bad anyway, in which case you would need to do this anyhow--

Our idea here is to get it down to low level signal straight from the head unit-- this way you're only running the signal through a line driver that you know to be good clean quality, rather than through a factory amp to speaker level, which will undoubtedly distort more quickly than the preamp level outputs of the factory head unit, (deep breath) THEN through ANOTHER inexpensive (cheap) piece of equipment known to be a line level converter-- THEN finally to the amp-- lots of chances for both noise and distortion you just don't want-- Now do you see why a line driver straight off the head unit signal is much better??

Here's an even better thought -- Cadence 6 band parametric eq-- 7v line driver-- It's $60 shipped and has a built in low pass xover, plus 3 outputs for 3 different amps-- This way you could run a few amps while using your factory head unit and have great equalization ability with plenty of preamp voltage for a good clean strong signal --

In order to feed it full range sound to send to all your amps you would want to tap into your left and right front low level signals to the 4 ch amp under the changer-- this is pretty easy to do and you can then feed a full system with 7v of full range preamp with 6 bands of parametric equalization as well..

It's single din for in dash mounting, but you can just as easily mount it to the bottom of your rear deck where it fits flush with the "beauty panel" for easy access-- it's kinda cool with motorized ***** that recess flush when you hit the hide button-- plus it's got a subwoofer mute and level control-- kinda cool too-- It would be even sweeter to mount this in the glove box --

labtec

the tests are being done with the car on.

thats a lot of information. i really appreciate! thanks.

I'm going to let it marinate and do a little reading. try to fully understand what it is ur recommending. I'll let u know what i decide to do.

1997sc300

The line level converter is your downfall.

Not to mention you are also amplifying the signal that went to the NAK sub. Who knows that could have a highpass filter at 20hz and only running 20hz-120hz or so.

What I mean is there could be a subsonic filter installed and running from the factory going to that nak sub.

In essence you may actually be amplifying a bad signal to begin with.

You must get rid of the factory stuff

Being in a sealed box your sub should be crossed over at 70-85hz or so.

Also adding polyfill makes the sound inside the box travel slower thus making the box seem bigger. You may not need it!

A ported box, by science will play 2-3 times louder at the same volume.

Another thing to point out is that you are probably not only amplifying a bad signal but you are also amplifying the distortion which is probably at least 10 percent coming from a factory unit.

There are other products you can buy but you would just be putting a bandaid on the problem.

One last thing you need 10 times the power to make your car twice as loud.

And of course it's voltage times voltage divided by ohms to find out the watts you are pushing.



I rambled here but you get the point get rid of that converter.

MJHSC400

simply put--

Take the oe amp out of the equation-- which lets you take the LOC out of the equation (they don't have the best rep for sq- which is direly important if you intend to run nearly 1000w to a beast of a sub that wants clean power) --

Taking those two out of the equation just brings you to the need for stepping up the head unit's low level preamp signal-- It's generally very weak-- you can try to run it straight to your amp, and it may work well, but I doubt it, and just by feeding that low signal to a hi voltage line driver, you'll be able to ensure that your amp/s get plenty of clean preamp power--

In this case 9v of preamp power will not necessarily have a big advantage over 4v, but 7v will have a HUGE advantage over .2v -- which you'll accomplish with the line driver I linked you to-- and you don't have to use that one-- A simple kicker 2 way xover/ 5v driver will work too-- it's just not near as cool as the peq/xover/line driver cadence has for sale pictured above--

The kicker 2way - http://www.woofersetc.com/index.cfm?...roduct_ID=1304

The sq I'm getting by just boosting my low level h/u signals is super good for retaining my oe head unit, and especially for retaining my front stock speakers entirely --(for now) --

Something like an audio control 2xs is exactly what we need to boost the low level signals-- I tried a $40 PIE line driver, and it was just plain crap--

I'm betting that's the problem you're having is your loc is just not stepping up the voltage enough to really wake that amp up--

I hope that was a little simpler--

labtec

I agree, the cadence does look very nice and will be sure to impress.

MJ and 1997sc300, I guess the consensus is that I get rid of the LOC.

ok....say I pull out the LOC and and buy the cadence for 60 bucks. How do you hook something like that up. What types of cables would I be required to pull?? It looks like it requires a lot of adjustments, is it relatively simple? How much additional out of pocket costs should I expect to incur (besides the $60). I'd mount it in the trunk.

thanks

MJHSC400

you would need to run rca level input to it-- which would be best intercepted just behind the head unit--

The diagrams on intellexual.net will tell you which wires to splice into and it will involve simply cutting one end's connectors off of an rca cable-- the outer ring is ground-- and this ground is common to both channels-- signal ground-- once the wire is cut, it would be the outer wire, while the center wire is positive--

This will tell you how to remove the head unit to get to it-
http://www.carstereohelp.com/stereor...usSC300Str.htm
SC400 Stereo/Climate removal How-To

you can also tap these signals at the amp in the trunk if you don't feel like running a wire and removing the head unit --- diagrams will tell you again how that is done--

You'll want to tap the front L and R signals (low level) with an rca cable, then feed that to the dsp -- (assuming the cadence unit) --

It will step up the voltage, which will be fed to the amp via rca cable--
You'll also be able to feed a mid/hi amp with it when you decide to upgrade to a better front stage amp--- which is where the adjustments will come in handy-- mainly for the sub you'll just be adjusting level and eq'ing it a bit if you want--

So costs involved will be a few rca cables-- I may have some if you need them--

Adjusting it will come with practice-- you don't have to adjust it at all, but I'm sure you'll end up messing with it and decide what you like the best--

Robert_J

Did you notice in the video that they were running the amp into a set of resistors? That provides a constant load to the amp. A speaker provides a reactive load to the amp. That means the load varies by frequency.

Via the impedance plot in Unibox, I'm showing that your sub is at 3.615 ohms at 50hz. Using the formula from here (I=V/r), I get I=45/3.615 or I=12.44. Then using P=VI or P=45*12.44 or P=560. So your amp is pushing 560 watts of power into 3.615 ohms.

Like you said, either way you wire up the amp, you get the same reading. That's right. Voltage is constant in this situation. You must know the resistance at the frequency (in this situation we are estimating based on a model). You find the current, then you find the wattage.

-Robert

MJHSC400

My statement was only based on the fact that we haven't actually bench tested this amp in a control to know it's clean output threshhold at the resistance load present--

That bit of info would help a lot in knowing where the amp should be operating within it's range of clean power production-- (being class d it would be more like relatively clean) --

560w seems low to me-- I'm still thinking it's an input voltage problem--

I never found out if that LOC has any level adjustment on it--- if so you may try adjusting it in the UP direction --

I would still prefer to see the preamps boosted straight from the head unit vs. amplifying it and de-amplifying it-- each step adds distortion-- the oe amp adds the most I'm sure-- which can limit output as well once the oe amp approaches clipping-- the clipped signal fed to the LOC is just reproduced and fed to the 1206d and in turn the 1206d is amplifying a clipped/chopped/reduced signal--

The most ideal would be a new head unit feeding the 1206d solid voltage, but the line driver boosting the oe head unit's preamp level is next best to that-- And it is nice to have the factory head unit to keep the car looking stock since it's not exactly a Corrolla--

labtec

The LOC i'm using is from David Navone (NE-7V). I tried to do my research and get the one most people were recommending. It does have adjustments and both are turned up all the way up.

1997sc300

That's your problem, the controls on the LOC are not volume controls.

I know you know this.

But you are just amplifying distortion, if they are turned all the way up id guess on a conservative scale that you are pushing about 25 percent maybe even 40 percent distortion to your amp.

Getting a better LOC is just going to do the same thing.

They all serve the same purpose.

Think of it this way, I am not sure if you have ever done this but I always tinkered with stuff when I was a kid.

If you take say a walkman and take the headphone wire apart and hook it up to a 15 inch speaker. There will be major distortion.

The speaker may not even move, but there will be a negative effect.

So much that in fact you could blow the speaker.

Anything turned up all the way is not good.

The Cadence thing the guy is recommending you are going to be in the same boat.

To be honest Cadence is not the greatest stuff either.

Stick with something made in the US. Audio control comes to mind, as well as some old school PPI stuff.



What you need to do is get rid of the LOC it is making your amp work harder. Amplifying things that dont need to be. Your amp is actually wasting energy by amplifying the distortion that the LOC makes.

labtec

hmmm, I understand what your saying but the guide for the NV-7V specifically recommened that the gain controls be set to maximum. I'm not saying your wrong, just explaining my rational for doing what I did.

If I remove the LOC and the Cadence will be the same problem, is there anything you recommend besides a HU change. The only LOC by Audio Control is $150 for a 6 channel which I think is an overkill.

1997sc300

This comes to mind,

Boosts voltage up to 11 volts. I dont know if these are made in the US anymore. Japan and US companies tend to make better audio gear. Stay away from anything made in China Korea or any other flea market type company. For the price it would not be a huge out of pocket expense.



http://cgi.ebay.com/NEW-Phoenix-Gold...QQcmdZViewItem

I still believe that the factory headunit is your biggest problem.


This is a step in the right direction though.