Hi,.. This is the setup I've decided on:

Looks solid to me, if you see an issue let me know.

My question is calculating the proper voltage when I set the gain controls on this amp. It has TWO gain controls, just for reference.

I get for fronts = sqrt(100wRMS x 4ohms) = 20v for gain voltage.

*Note: The AMP is rated at 125watts RMS per channel unbridged.

Then for sub,.. I get sqrt (300wRMS x 4ohms) = 34.64v for gain voltage on sub.

*Note: The AMP is rated at 380watts RMS in bridged mode.
(Which is why this 4 channel amp looks good, with headroom in it, to run this 3 speaker setup.)

I'll be using Channels 1 and 2 in stereo for front 6.5 + .75 tweeters which are rated at 100w RMS.

I'll be using Channels 3 and 4 in bridged mode on ONE JL 10" w0 which is rated at 300w RMS.

Are my figures right?

And I'll be playing a 50hz Track with headunit volume at 85 percent. (Some say 75%,.. others 85-90 percent.

Thanks,

 

Those voltages are correct. However play a 1000hz tone for your front stage and a 40hz tone for the sub so your crossovers wont mess with the voltage and cause you to blow equipment.

And I typically only use 3/4 volume. It just depends on your head unit and when it starts to clip the signal.

 

Ok.. those voltages are for the RMS of the speakers, not what the amp can put out.. I'd like to leave a little headroom in the amp.. and it has a touch headroom for the fronts (amp 125w per channel.. speakers 100w).. the sub the amp has more headroom.. with 380watts,.. while the sub rating is 300wattsrms.

Tone CD wise.. I have heard play a 50/60 hz tone.. so 40hz is your recommendation,..

And 1000hz tone when setting the gain for the fronts. Gotcha

I'm sure I can find it.. but happen to have a link to two high quality tones that play for a long time I can burn on a CD?

Thanks

 

If you have Bluetooth or aux input on your radio and a smartphone you can go to www.onlinetonegenerator.com

I don't know if ROE still has the download section, I'll have to check.

I'm aware those are the output voltages, I've set many amps up with a DVOM. I just had to retune mine the other week because I changed out the head unit. I'm running 100w front and 750w sub.

And yes, use the 40hz and 1khz tones. If you have a HPF set on your front stage at 80-100-120hz and you try to tune with a 50/60hz tone you will never reach 20v.

If you're going active (I know you're not) you use a 40hz for sub, 1000hz for mid and 10000hz for tweet.

 

http://realmofexcursion.com/downloads.htm

1khz and 40hz. Right click the link and save target as. (or whatever your browser offers)

 

I have an Aux input.. not sure it's hooked up to plug in from the front,.. but it's usable if I'm pulling the unit out. I have a USB port of course.. and Iphone (ipod whatever) port up above the headunit.

But, I just went to the page you linked and Dl'ed the 40 hz sine wave, and 1k hz sine... Thanks, nice find.

I've never set an amp in my life. I just learned the science behind it two days ago.. but it's simple enough with a DMM,.. I use a DMM all the time.

I had a question about the output voltages,.. and some other guy said "Just put your DMM on the amp.. turn the gain until the max voltage occurs and then back it down slightly from that." I find that to be bad advice. Why not simply adjust the voltage to what the speakers handle RMS voltage wise for X watts RMS on the positive terminal with the Headunit up at 75-80 percent? That's what I intend to do anyway.

True, and the crossover which I think is 100hz on the Front components I'm looking at wouldn't allow the 40/50hz through anyways.

The MB Quarts 6.5 , coaxials, are 70watts rms.. and I believe the passive crossover on them is 80hz.. But the Crossover says "12dB" .. how does that translate?

I like going active crossover.. it's not really expensive,.. and helps dial stuff in much easier "for me".. but you are right, I'll likely not go active initially.. But putting a crossover in later isn't a big job to be honest.. you don't have to take your car apart like the initial install to put an active crossover in.

My ears are a little different than most.. With an active crossover I tend to knock off the bass from my fronts at a higher frequency than most.. and let the subs handle most of the lows. And, my ears love a reverse bell curve (U) shape EQ setup.. More power on the low range, and the high range.. and lower in the middle. I like clean and crisp treble.. I hate flat sounds,.. In friends cars I'm always going into their radios audio settings and adjusting the bass and treble (most of the time they've never touched it)..

Appreciate the links.

 

I started out in audio on Realm of Excursion back in like 05. It's sad that the forum died.

I can't count the number of amps I have set up. I do them all the same. No boosts turned on, filters set first, then adjust the gain from all the way down up till the desired AC voltage is reached at the output terminals with the head at 3/4 volume.

You still need to set your HPF on the amp for the front stage so they wont try to play too low (most people set it around 80-100hz) And the LPF for the sub (typically 60-80hz)

Personally my car has the fronts set at 40hz and the sub set to 60hz. My sub can't get that high but the doors have no problem playing low. They blend nicely.

The 12db is the slope at which the crossover effects the output. It reduces the output 12db per octave. If you're looking at it like a chart, 8db would be a long downhill ramp as you go up the frequency range. 12db is average and 24db is like a cliff.

Going active is easy, just have to have the proper crossover or an amp with them built in and run an extra set of wires.

And your ears are just like everyone else. Human ears lack in the upper and lower range so it's very common to see the U shaped EQ. Personally everything in my car is set flat, I put my RTA mic in there and on pink noise it plays flat all the way across the board except the substage is considerably higher.

 

I'll run the HPF on the fronts at about 80hz.. to blend nicely with the single sub.. All I'm after is at minimum the equivalent of the Stock "premium" package with the single sub that comes with these cars.. and I think the system I'll set up will surpass that. So my wants aren't high. Looks like I'll probably end up spending close to a 1,000 just for that though,.. nothing is cheap that's worth a crap.

Though the fronts come with passive crossovers.. so setting the amp at say 80hz.. the 80-100hz probably won't even get to the speakers.. as I believe the ones I have selected are cutoff at 100hz by the passive x-over.

As for my ears -- I didn't mean they were literally physiologically different. -- I just have a preferred sound,,.. many people do, and many people don't have an "ear" for it. I've tuned other peoples home and car systems (not amps) but their crossovers, eq's, and such to what *I* like and they thought it sounded fantastic.

But, a friend of mine used to always tell me I had the treble set too high in my vehicles.. but no one else did. So he liked a flatter high end. That's what I mean by "my ears" .. which is more, really,.. my brain I suppose.

While we are on the subject -- I'm going to be putting the amp in the passenger glove box -- I need an amp that can push 100wattsrms x 2 and at least 300watts x 1 simulatenously.. They one I've picked is about $200-250 or so,.. it's an A/B class. Do you know of any other amps in that range that can push that (essentially one amp for it all).. that are designed to run cool? So it would have a better time in the confines of a shut glove box?


This is the amp I was pointed to by some people

http://www.ebay.com/itm/CT-Sounds-125-4-amp-amplifier-125w-RMS-250w-MAX-Class-A-B-4-Channel-2-Ohm-/121148730300?pt=Car_Amplifiers&hash=item1c3506ebbc
And, had that the brand was not junk.. and it'd be a good mid-range amp to drive my speakers.

As you can see it has 25watts of headroom per front speaker, and my sub is 300wattsRMS.. so will have 80 watts of headroom for the bridged output to the sub.

Also -- What do you think about me putting my Coaxial MBquarts in the rear just as fillers? They are 6.5" with 1" tweeters,.. 70watts RMS.. as pictured here (from Circa 1999):

http://www.flickr.com/photos/111739693@N04/11445848745/
Or would adding those Quarts behind me be TOO much high end? (Running a single JL 10" W0 sub at 300watts RMS.)

If you think those would be smart to install,.. I'm gonna need more amp.

Something that can push 70 watts x2, 100watts x 2, and 300watts x 1. So a 5 channel amp? Hrmm.. I know two amps is a solution as well, but less saves space and sometimes money.

If you were doing this, how would you go.. I think my system is all linked at the top of the post.

I had those Quarts in my 300ZX with 2 JL 12" W1's.. and it sounded phenomenal.. but WAYYY too much bass for me now.. I want about 1/10th of that bass. -- The 300ZX with just the 2 Quartz coaxials in the front doors were all that cabin needed. The 350Z is about as close as you get to the 90+ 300ZX shape/acoustics.

 

The stock Bose stereo sucks. Personally I don't have any rear fill. My front stage is loud enough to cover up everything.

There are very very few 5ch amps and they are too big to fit in your glove box.

And I only run Sundown amps as they have been best out of the ones I've ran. Plus I know the owner so that helps out.

No amps are designed to run "hot" but some do get hotter than others in the same setup. Electronics do not like heat.