Gains, voltage, preouts etc.

[ParDeus]

Hello all, been lurking for a while, finally registered.

After a 7 year hiatus from having a system, ( I was listening to AM the WHOLE time lol) I'm seemingly a bit rusty. I own half of a stereo business in FL, but am now living in TN.

Anyhow, I always had an oscope to set gains before, and I do not up here. So using dmm, I'm getting virtually no bass. Right now I have 3 amps at my disposal. An Alpine mrd1005, a MB Quartz onx 1500.1d, and a MA Audio hk401sx (I know, I know). I won't have any of my MMATS amps for a little while.

Head unit is a kdc x995, 4v preouts. Setting the Alpine to 4.0v input would barely register any bass, whether driving my 2 mtx8000 15's, or my 2 garage sale find dd 9512's. Boxes are decent, not optimal though.

SO.....

Let's say my measured ohm load at the speaker terminals are either 2.5, or 1.4. Would I use that in my dmm calcs? Or stick with what the ohm load "should" be?

Also, lets say the MB is rated at 1500w rms @1ohm, yet only takes 4ga power wire and isn't popping a 100w fuse (I always fuse low for safety).

My car charges from 14.4-15.1, and it drops to 13.8 when the bass notes hit.

Any guesses on what power I should figure for?

Nobody has a scope around here. The local stereo shops are awful, one told me oscopes are "old" tech, that his ear is more accurate. I said, "ya, I feel ya, my buddy is an electrician and doesn't use a dmm, he sticks his finger into circuits because he can tell what voltage and amperage it is by how bad the shock is". They didn't like that.

I paid the other shop to set my gains, and he turned the gains to 8v and the bass boost ALL THE WAY UP. +18db lol.

I'm in Greeneville TN, BTW.

I would gladly paypal one of you for your time.

Thanks

[ParDeus]

Also, I have searched for this answer for 2 weeks to no avail.

Everywhere says if your HU is 4v preout, then set the gain at 4v sensitivity. Well, we know that many hu don't put out that voltage until most settings are maxed, in which case you're clipping the signal anyways. (most likely)

I understand a little clipping isn't bad, but I don't want to ruin my $200 9512's lol. And only one is hooked up currently.

I guess I'm screwed without an oscope. Too many variables...

[Lbox88]

Nobody has a scope around here. The local stereo shops are awful, one told me oscopes are "old" tech, that his ear is more accurate. I said, "ya, I feel ya, my buddy is an electrician and doesn't use a dmm, he sticks his finger into circuits because he can tell what voltage and amperage it is by how bad the shock is". They didn't like that.

LOL good answer. Couple guys in the TN area, hopefully one of them can hop in here with a DD1 or something.

[Aj11]

sounds like the guys at that car audio shop and my local shop got trained at the same spot.

just google a volt calculater. put in the ohms and watts should give you what you need. 1000w=31.6 volts @ 1 ohm

1400w =37.4volts @ 1ohm these are just some examples

[FUKAZ28]

Subcribing to this one.

[ParDeus]

........here we go with the mindless bashing. You both are trolls. You post nonsense with nothing to back you up. And y'all are really starting to piss me off with your ignorance.

sounds like the guys at that car audio shop and my local shop got trained at the same spot.

just google a volt calculater. put in the ohms and watts should give you what you need. 1000w=31.6 volts @ 1 ohm

1400w =37.4volts @ 1ohm these are just some examples

I get all that, but do you use the measured or projected impedence?

And I'm sure input voltage from the alt plays a role, no? I have a 100a fuse inline, and a "1500w rms" amp is not popping it.

I think I'll just bite the bullet and buy another oscope.

[Aj11]

i always go by what it says on the box. i dont tune it to max, my amp is 1400w rms at 1ohm so it should be 37.4 volts but i have it at 35 volts. adjusting for variables. the fuse is there to protect your wire/car not your amp! if your running 0g wire and pushing 1500w rms your fuse should pop. do you have your big 3 done? what amp is your Alt? if you have a 90amp Alt yea a 100amp fuse prolly wont pop but your also prolly not getting the full juice of the amp either!

just find the Volt for 1500 @ 1ohm use a 40hz wave and tune a Volt or two lower you should be fine. if i were you I'd upgrade my fuse and get a Volt meter/anl fuse holder it's a great way to keep a eye on your system. they can be had with a fuse for $15 on Ebay. i have one on my floor by my 4x4 lever and one in my Bass knob thanks to Ct sounds and there amazing products!

pm me any time for little things I'm prolly one of the few on here who still use a mm

if i were you I'd save up and get a smd dd1 there about $150 plus shipping. I'll.be putting my order in very soon. i figure if i have a few thousand in gear what's another $150 to protect it!

[ParDeus]

Good stuff, thanks.

I have a 130a alt, and part of the reason for fusing low was just to get an idea if threes apps were pushing rated. I had a local yokel tell me my Alpine mrd1005 will do 1600w rms at 14.4, and I doubt that. The birth sheet says 1039w. I found a nice scope for $175 local, and I figure that's my best bet.

Btw, I have no idea how that other quote made it in my above post, no offense intended.

[Aj11]

get a dd1 not a oscope! there way easier and better! just plug it into your amp watch for it to distort back the gain off till it goes away and Boom your perfectly calibrated! it's so easy it's dumb! read some reviews on it man!

i would run the mb quart over the other amps myself, and make sure you do your big 3! 0g or better! if it's not done, when you do it that 100amp fuse will pop.

[Guest]

alpine > mb quart.

big 3 wont make the fuse pop.....

reason why you're not blowing the 100 amp fuse with that mb quart, is probably because your gains arent tuned right to make the amp output its full power.