OK, tell me if my math is right here...

Jstas

...if I get two SR 124 DVC subs, wire them up in parallel to present a 2 ohm load and then wire the two DVC subs in a 2 ohm load up in series, they would present a 4 ohm load to an amp.

If I were to use this beast:



http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=18038

# Signal to noise ratio > 115 db
# T.H.D. < 0.02%
# RMS Power @ 4 ohms: 2x480W
# RMS Power @ 2 ohms: 2x800W
# RMS Bridged Power @ 4 ohms: 1x1600W
# Damping Factor > 500
# Input sensitivity is 0.15 - 12.0
# Crossover slope 18dB
# Crossover Frequency 50-4k
# Dimensions: 9.5 x 2.3 x 21

It would run a 1600 watt load with roughly 400 watts per voicecoil.


That would end up being alot of good, clean, thump!

Of course I'd need to run a 200 amp alternator to handle that amp plus...say...this amp:



http://www.onlinecarstereo.com/CarAudio/ProductDetail.aspx?ProductID=18039

# Signal to noise ratio > 115 db
# T.H.D. < 0.02%
# RMS Power @ 4 ohms: 4x70W
# RMS Power @ 2 ohms: 4x120W
# RMS Bridged Power @ 4 ohms: 2x240W
# Damping Factor > 500
# Input sensitivity is 0.15 - 12.0
# Crossover slope 18dB
# Crossover Frequency 50-4k
# Dimensions: 9.5 x 2.3 x 17.5

and bi-amp a set of SR6500 components.


That's alot of power and alot of draw. If the truck is going to have a high power ignition system plus all the other electronic gizmos associated with a high power engine, it's gonna need juice and tons of it. It'll have a kick-**** stereo though and I might be able to get back into competition with it again!

MacLeod

Or you could wire them both in series for an 8 ohm load per sub, then wire both subs in parallel to the amp for a 4 ohm mono load.

I doubt it makes a difference but thats the way I would do it that way the amp is being wired in parallel.

I like the first amp. 800 watts per sub would be just right.

Jstas

Well, the way I figured it, I could use small jumpers on the DVC's on the subs and then only really need one set of binding posts and cables to the sub from the amp. Less wire, less distance, better efficiency. Plus, then, I'm not jumpering binding posts on the outside of the sub box. I can also seal the wires inside the box. But either way will work I suppose, just which one would be a cleaner install?

BTW, the first amp is for subs. It's a 2 channel amp, A/B class I think. I didn't download the white papers on it yet. The second amp I posted is for a 4 channel amp at 120w per channel. If I use the SR components ability to bi-amp, I use the Kenwood PS-955's ability to switch the RCA outputs to non-fading and run the tweeters off the front channels and the woofers off of the rear channels. On top of that, you can use one or two of the BLT-4 units from Soundstream which will balance your left and right inputs which will help with any artifacting that you might experience with a bi-ampable system. I'd have to see if that was within rules but hey, any help on imaging I can get the better.

Besides, we are talking custom fiberglas dash here so placement of audio components is going to be a planned for deal.

MacLeod

Custom dash?! Awesome!

Remember, in SQ terms, the more drivers you can put on the dash the better! At least put the mid and tweeter up there.

Jstas

Subs will be mounted behind the seats. Mids and tweeters will probably be mounted low and angle in a tad.

I'm going to redo the whole interior. It'll take a while but between me and my brother, I think we can get it done. I'm going to find Thunderbird seats, get them reupholstered, a custom fabbed up sub box with dual, separated chambers behind the seats and the amps on a custom panel on the rear wall of the cab. I have an idea for a sliding glass rear window but I don't know how feasible it will be. With a center console and wraparound dash, I'm going to wrap the dash in a tweed/leather deal. All panels will probably be a dark mahogany veneer with polished brass accents. Gauges will be these bad boys:



and this Tachometer:




With this clock:


I can hide the electronics behind a movable panel or just leave them out because it's a MASK unit. I'll get a steering wheels like this:



If I have to, I'll get a chrome one gold plated or gold leafed and just lacquer over it to keep it from flaking.

I'll grab a unfinished wooden shift knob and get the shift pattern burned into the top, stain the the knob to match, sink a threaded plug to fit a classic Hurst shifter bar, get the bar gold plated and lacquer the knob too. That'll finish the whole look. The inside will get painted the same color as the outside. Toyota had color called Champagne a while back it's absolutely gorgeous! Especially with chrome!

I 'll get 15 inch steel ranger wheels from a later model, get a pair widened for out back, paint them black with center caps and trim rings. There are plans to cut 3 inches out of the cab height too. Oh, a wooden bed floor too with a false floor to hide the 35 gallon gas tank where the spare tire currently is and hide the air bag tank and compressor under the front of the bed. The spare tire will be mounted on a custom mount in the bed. This is by no means an easy project and it's a long way away from being done. When it is done though, it's gonna be sweet!

strang22

dont seies them....thats what i would say

Jstas

strang22 wrote: »

dont seies them....thats what i would say

If you can't spell, stay out of my ancient threads, moron!

exalted512

I know its an ancient thread, but I would series each sub to 8, then parallel them back down to 2 at the amp. Ive also heard its bad to series two subs together. Supposedly some kind of interference. I thought JL had an article about it, but I can't find it.

I remember they said if you wire 6 subs in series with each other, and push one of those subs down, the rest go up (not in a box and not hooked up to an amplifier) and thats the interference theyre talking about. Cant remember exactly though.
-Cody

exalted512

http://mobile.jlaudio.com/support_pages.php?page_id=161
2nd paragraph. Doesn't really give an explanation though.
-Cody

exalted512

Found the explanation
http://mobile.jlaudio.com/support_pages.php?page_id=163
It is far less desirable to make subwoofer to subwoofer connections in series. Because of slight and unavoidable differences between speakers and because of the high likelihood of uneven loading between different speakers in a car, there will be slight differences in the mechanical behavior of the two speakers in series. These differences in movement result in induced voltage (called back EMF) being created by the speakers across the series connection. This effect causes a problem when two speakers which behave differently are connected in series because the speakers can modulate each other (cause each other to move), resulting in distortion. The problem becomes more serious as more speakers are connected in series.

A good experiment to show the effect of back EMF is the following: connect four speakers in series and short the positive and negative input leads of the series circuit. Push down on one cone with your hand; you will notice that the three other speakers will move in the opposite direction of the one you are pushing. Now, reconnect the speakers in parallel, short the inputs and push down on one cone. The speakers will not modulate each other because each one is shorted directly.

Back EMF modulation is not a concern when the voice coils of a dual voice coil speaker are wired in series to each other because the coils are physically coupled on one moving mass. Therefore, they cannot possibly modulate each other because they cannot move independently.
-Cody

eloplayspolo

did this truck ever get finished? i wana see!