So how does this combination "sound" to you

[MrDHEJ]

Going in a 1999 Chevy Silverado Ex-Tended Cab

Front doors: MM6 6.5"
Side rear panel: MMC 4x6
Under rear seat: JL Audio stealthbox 12"

US Amps TU-600 driving the MM6's
US Amps USA-200X driving the MMC 4x6's
US Amps USA-1000X driving the sub

How good do you think this combination would be in terms of SQ?

Only problem i may encounter is where to put 3 amps. Only thing atm i can think of is putting the amps in a box ajacent to the sub on the floor under the rear seat.

[TrappedUnder Ice]

Nice choice in amps btw.... I wonder though...what that JL stealth box uses... cause thats a lot of power for JL subs (1000x) and hate to see you smoke em'

[Jstas]

Just pull the crap JL subs and unload them on eBay to some kid that buys into the JL hype for 3 times what they are worth and load the stealth box with subs that can handle the power.

[MrDHEJ]

LOL nice plan you got there jstats.

the specs for the sub in the stealthbox is...
the 12W3v2-D2 in a sealed, downfiring enclosure. 300 Watt power handling. Wired for 4 ohm mono.

what sub would you guys recomend?

Honestly, now i'm wondering if all this is going to be to much. the cab volume in my truck is a TON less then a car, so it's not going to need a whole lot to sound loud. and i'm just not sure i can crame 3 amps and maintain a stealth look that's clean and un-noticable.

I think there is enough room under the stealthbox to put the sub amp, but space is a premium on the other side for 2 amps. and if i put them in a box to conceal them i'm going to need suplimental cooling to circulate the air past the amps. and i don't know if stcking them on top of eachother would be a good idea.

[sntnsupermen131]

mount the amps behind the back seat under the rear window
i have a 96 gmc extended cab and thats where my amps are
and i jstas wasnt kidding about getting rid of the JL...
they make awesome stealth boxes, crappy subs
-Cody

[MrDHEJ]

sntnsupermen131, i thought of that at first, untill i looked. In my 1999 silverado there is only about 1cm of space at the top of the back seat, and about 8cm at the bottom. But once the seat is up it's about 1cm top or bottom. They did a perty good job of not wasting space back there on the later models. :/

[Jstas]

The stealth box is not going to be too much with 1 woofer. For the human ear to hear bass, it needs to be loud. The lower in frequency you go, the louder the volume needs to be to adequatly hear the bass response. That is why subs take considerably more power and space. They need teh power and displacement to play the low notes audibly enough to blend with the rest of the music being played.

The nice thing about the stealth boxes is that they are usually out of the way. If not, they have usefulness other than a speaker enclosure to them. They also match your interior so well, they blend in. Hence the name "stealh box".

As far as what speaker to recommend as a replacement, that is difficult. If you can find out some info, I'd better be able to make a recommendation. Basically, what is the internal volume of the enclosure? It is a sealed enclosure and right now, it looks like a MOMO 2124 would work best and compliment your choice of full-range drivers well.

You should be able to call JL Audio customer service or tech help line to find out the internal box volume.

[sntnsupermen131]

Originally posted by MrDHEJ
sntnsupermen131, i thought of that at first, untill i looked. In my 1999 silverado there is only about 1cm of space at the top of the back seat, and about 8cm at the bottom. But once the seat is up it's about 1cm top or bottom. They did a perty good job of not wasting space back there on the later models. :/

well thats ****ty, im going to get a new model gmc in a couple years...
-Cody

[MrDHEJ]

Yeah it is, but what do you think of mounting the amps IN the bottom part of the seat? That way when you flipped the seat up you'd be able to see the amps.

[sntnsupermen131]

you could do that too, just slide a piece of wood under the lining of the seat, screw the amps in
wouldnt mount them on the floor for fear of getting kicked and breaking off terminals
-Cody

[MTXMAN]

Very nice choices on amps. just hold of on the 1000x till you decide which sub to replace the JL with so you get the right ohm load, if you get a dvc that bridges to 2ohms you'll want the 1000 instead... anybody know if an IDMax would fit in there?? i'd say go with the Diamond audio TDX's as they're my personal favorite but there's no way in hell that that magnet would fit in that box... check em out at www.diamondaudio.com they sound gorgeous...

[MrDHEJ]

MTXMAN, i have decided to go with the Polk c500.1 and c400.4 amps. I'm sure i am going to get good crisp clean sound with this combination. No it won't set DB records, but that's not what i want.

[MTXMAN]

no need to explain to me dawg, it's your car and you're the one that's gotta be happy with it. I hope it goes above and beyond your expectations :D

[MrDHEJ]

MTXMAN... I just went and looked at that sub from TDX. dam that's big! Not sure if it will fit in the stealthbox, but what is the cost of that monster?

[MrDHEJ]

sntnsupermen131:

Guess what, I think 3 amps WILL fit behind the back seat. There’s trim at both sides of the back seat, and some sort of vent with ducting. Not sure why these were put in there, but the ducting can be trimmed, and I’m not even sure the vents need to be there.

Anyway, with the seat up there’s about 3" of room, which should clear the amps. I made some cardboard replica amps in the sizes I’m trying to put back there and it should fit. I'll try and get some pictures today and show ya the plan.

The down side is unless you carry around an 18mm wrench you can't display the amps. The up side though is it retains the stealth look, and security of your investment.


MTXMAN:

Ok, as we were talking in the other thread about these amps, it's clear that the US Amps produce better SQ then the Polks. I had set my mind on the tube amp but once I looked at the regular USA-600 amp it looks like it is louder "Signal/Noise Ratio: 105dBA" AND has better SQ "THD at Rated Power: <0.006%". Vs. the TU-600 amps 100db and thd <0.05.

So why would the tube amp be better?

USA-600X
Two Channel Class AB Amplifier
Total Power Output: 600 Watts RMS
THD at Rated Power: <0.006%
Stereo Separation: >98dB
Signal/Noise Ratio: 105dBA
Frequency Response: 5Hz-50KHz
Fuse Rating: 75 Amps
Variable 24dB Low-Pass Active Crossover
Two-Ohm Stable
150 Watts x 2 into 4 Ohms
195 Watts x 2 into 3 Ohms
300 Watts x 2 into 2 Ohms
600-Watts Bridged into 4 Ohms

TU-600
Two Channel Class A Amplifier Direct Tube Input
Oversized MOSFET Power Supply
Total Power Output: 600 Watts RMS
THD at Rated Power: <0.05%
Signal/Noise Ratio: >100dBA
Frequency Response: 15Hz-50KHz +/-0dB
Fuse Rating: 60 Amps
Two-Ohm Stable
150 Watts x 2 into 4 Ohms
300 Watts x 2 into 2 Ohms

[MacLeod]

Cant rely on factory specs that much. They sometimes "exaggerate" the ratings or just flat out lie. Take Xtant. Their amps are rated at 1% THD! That sucks. Yet they are routinely in the winners circle in SQ competitions. JL Audio 300/4 amp rates signal to noise at 108 and Carsound.com's review tested it on the bench and rated it at 120!! Then you have amps like my beloved little 40x4 Alpine. I would wager that this thing would be lucky to hit 35 watts on a good day! And hell, Pioneer amps are rated THD at .004%! But would you rate a Pioneer amp better sounding than a .02% Precision Power amp?

Numbers dont tell the whole story. I would suggest just going to a shop and giving different amps a test listen. Take the CDs you listen to and know well and check out the different models. Dont rely on what I think sounds good, be your own judge.

[MrDHEJ]

Macleod:
Theres no one close to me that has US Amps, so i must go on "word of mouth" or ear, for which is better.

Jstas/MTXMAN:
The JL Stealthbox for my truck has a volume of 1.25ft and is sealed. So what MOMO sub would be a good choice?

sntnsupermen131:
I took some pictures today, i'll upload them here soon at the follwing url

http://www.renagaderc.com/automotive...silverado.html

Looks like i will have to cut the holes in the mounting bracket so the seat can slide forward another 1/2" to an 1". The way it is now i wouldn't want to use the radio when the seat is up becasue the back seat cushin will touch the amps and block cooling. With the seat down though theres like 2" to 3" of clerance. You can see in the photos the ducting i was talking about. Think i will call GM tomorrow and see why those are there.

[MTXMAN]

You get a completely different sound with a tube amp. Jstas can back this up having delt intensely with tube amps in his home stereo. It's much warmer and more detailed. while the class AB amp will be louder and covers lower frequency(ones you'll never use anyway) and has a lower THD% I personally would prefer the tube because of the type of sound they reproduce. run a search on the site for tube amps and look at what people say about them for home audio cause the results will be similar. warm detailed gorgeous sound. :D

[MrDHEJ]

that's all i needed to hear. :) Thanks man.

So as far as the JL box having 1.25 feet of volume, what 12" sub would you recomend? Are the polk sub just as good as there full range?

[startzy]

dude id go with a polk sub if the jl box is sealed the polk gnx124 will fit in a sealed box with 1.25 of air space and that sub kicks ass man

[Jstas]

Well, about the tube amp, I have reservations about them in cars. Not because of sound quality because they do have a very warm, natural sound. Tube amps are delicate and susceptible to vibrations. I worry about them in cars because a good bump could break a plat or filament in a tube and then you are buying a new tube to replace the broken one. That can be expensive depending on what tubes that amp uses. But if you want to go with a tube amp, more power to you! I will warn you though, tube amp power is not like solid state power. 100 watts of tube power has more grunt behind it than 100 watts of solid state power. It's not physically more power or over-rated or anything like that. Tube power is just delivered much smoother and tube amps often have a higher sensitivity rating than thier solid state counterparts. The solid state amps can out-muscle the tube amps, especially in D-class form. But I have yet to hear an AFFORDABLE solid state amp that comes anywhere close to the richness of a tube amp.

As far as woofers goes, the GNX is what looks like will fit best for a 1.25 cubing inch box. However, you are not limited to it. If you can fill in some space inside that box, you can reduce the volume of the box internally. If you do that, you can make the box internally smaller and get a Polk MOMO 2124 which I feel is a better sub than the GNX.

To reduce space, get creative! Since the stealth box is most likely an odd shape, you could get a guage plastic bag like what you would find in a sandbag. Fill it with sand and wrap it in burlap. Figure out a way to safely secure it inside the box so it doesn't move and stuff the box with polyfil. It's not the best solution but it would be easy to get say .35-.40 cubic feet of sand in a bag(s) to reach the .88 cubic foot requirement of the MOMO 2124.

If the box is flat, figure out the volume of some lengths of wood that will fit inside the box and fasten the wood inside the box to reduce internal volume. To determine the volume displaced by the wood, multiply length by width by height of the wood and just add enough to equal .35-.40 cubic inches. Use measured sizes though because milled lumber is never milled to an exact dimension other than length. A 2x4 is never 2 inches by 4 inches. Believe it or not, that is a standard though. Again, fill with polyfil and go to town!

Just remember, it is always better to build the box properly but sometimes we have to compromise and that means something like a stealthbox needs to be modified to fit our needs and appication. There is nothing wrong with it and if you take your time and think about what you are going to do, you will get very good results and be exteremly happy!






Until the upgrade bug bites again! Then you can come to the Club Polk support group...Hi, my name is John and I am an audio junkie.

[PoweredByDodge]

ok - normally i dont chime in on a thread until i actually read it - and forgive me if i'm saying things that were already said, but i'm about 10 minutes away from my lab final and i'm just tryin to get in what i can here...

i'll try to respond better (if necessary) when i get home later.

as far as the amp -- the 1000x is 1000 watts... dude... why not buy like a 300 or 400 watt amp -- that 1000 is HUGE in both size and power - - both of which you do NOT need.

second -- you cannot fit an idmax in a stealth box... regardless-- 1.45 or around there cubic feet sealed birch ply or mdf box and dont fk around with it cuz you will blow the box apart... literally. wicked sick heavy sub and creates and assload of pressure.

and IDQ however will fit. but... ifyour'e gonna do an idq - why not just do a polk momo 2104 or 2124 -- i'm more partial to the "we sorta are like old db's / dx's" polk subs that just came out... i dig em.

just watch air space... check on that -- from what i know, JL audio subs take LARGE airspaces -- polk and id and most good sq subs take small spaces.

alpine type R might be a better replacement - u can put it in a bigger box i think -- so if u have a "big" stealth box -- check that out.

as as your other speakers -- why the hell aren't you getting a 4 channel!!!!!!!!!!!

pick up a 75 x 4 USamp tube or not tube is irrelevant -- tubes are nice, but john has expressed concerns which are probably valid especially in a pickup that's shaking around a lot (not as smooth as a luxury car or whatever) -- but think it over -- i really think a 75 x 4 is plenty powerful for 4 coaxial speakers dude.

on that note -- beer and chicken -- imma go have a cigarette before this thing -- WISH ME LUCK!!!!!!

[MacLeod]

You dont need that much grunt in a pickup. There is a lot less room in there and the sub is about 2 feet away from you. Ive got 140 rms running an MTX 8 in a Ram Quad Cab and its plenty. Now this isnt a ghetto blaster, you cant really hear it outside the truck but inside its plenty. I would say that anything over 250 is a waste as youd never use it all. It would be way to loud and rip your eardrums out.

The same goes for the mids/highs. Ive got 4 speakers getting 40 rms each and again, its plenty. Its enough to run down the freeway with the windows down and still hear everything. I would say that the best for a pickup SQ system would be 50x4 and 250x1. I think that will give you a good, clean, really stout system. Any more than that is simply not needed and will not ever be used. Now if youre wanting to blow out the windows in the car next to you or enter some DB Drag competitions then yeah, go as big as you can. But its kind of like driving an 18 wheeler as a daily driver. Do you really need all that room?

Thats the cool thing about a truck. You dont need 5 zillion watts to have a stout SQ system.

[MrDHEJ]

All good information.

As far as the coaxils go, the reason i don't want to run a 4ch amp is because the MMC460 is max 100watt, so 75watt from the 4 channel comes up short, and the MM6's are 150wats, which is 1/2 of the 4 channel. So to get each set at there max the TU-600 and the USA-400x will be perfect.

With tubes yes i agree there is a risk, but for a company like US Amps i'm sure they tested them quite well, so i will give it a shot.


Now as far as the sub and sub amp goes, yes 1000watts is allot, but the Polk 2124 can handle almost all of that. Will i use it all, all the time? No, who does. But when i want to use it, i want it to feel like someone in the back seat is kicking the **** out of me in the back. :)

All in all my main goal is SQ, and the US Amps in combination with the polk speakers will come thru. And on those days i feel like ringing it out the power will be there, and everyone close will know i ain't messing around.

Plus later on i don't want to be saying "Man, wish i had gotton those other amps".

BTW, the USA-1000x, TU-600, USA-400x will fit in the truck, out of sight, out of the way. :)

BTW, with the Polk 2124 will that take the USA-1000? or the 1000x.

[sntnsupermen131]

you would want the 1000 for a single 2124
and the mmc460s are only rated at 50, not 100
and if you crossover the mm6s at 100Hz, you could probably but 250 watts on them if they were nice, clean watts, and youre not a total idiot...
i have 225watts going to each crossover safely on a fosgate
that amp is awesome
i wish RF would still make them like they used to, its almost doubling its rated amount of watts
rated at 500, putting out almost 850
the new versions i have put out about 75 watts over the 500 mark
they dont make them like they used to...
-Cody

[sntnsupermen131]

also, why dont you go with a mm124 instead?
-Cody

[Jstas]

Originally posted by sntnsupermen131
also, why dont you go with a mm124 instead?
-Cody

Because the mm124 will be alot harder to make work in a large Stealthbox like he has.


As far as the power levels go, power levels are not so much for volume as they are for sound quality. You don't have to use all the power but the sound does get better with more power because when you listen at normal listening levels, you have alot of power overhead available. It reduces the chances of the amp clipping and helps stave off distortion because there isn't enough power to move the cone accuratly fast enough. So just because it is a pickup truck and you are sitting almost on top of teh speakers doesn't mean high power is a waste.

As far as subs go, they usually require 3-4 times as much power as your fuill range speakers because they need to play that much louder. They need to play that much louder because the decibel levels of bass increase almost exponentially as the frequency levels decrease. That is because the human ear's effectivness decreases as it approaches its limits. It's something like for ever step down in frequency from 50 Hz, the decibel level has to increase one point or something like that. By the time you reach 20 Hz, you have to have your sub playing that much louder than your full-range speakers, just to be able to hear the 20 Hz frequency. Therefore, a high powered sub is necessary for your ear to be able to physically hear all the information in the bass track.

[MTXMAN]

if it's a 4 ohm sub get the 1000x, if it's a 2 ohm sub(dual 4ohm vc's) get the 1000... simple :D

[MacLeod]

I guess it all depends on what kind of music you listen to. I listen to metal and my little 140 watts to my sub is usually too much. It drowns out the mids/highs which is 40x4. If I turned the mids/highs up much more my ears would start bleeding. A screeching guitar starts to become painful at a higher level. Thats why I think 50 rms is plenty on the mids and 250 is all you need for the sub. Its enough to be plenty loud without approaching its max ability. I rarely turn my volume up more than halfway and its almost to the point of hurting then (well provided its a good recording).

I guess if youre more of a hip/hop guy then a lot more ass in the bass is what you need.

[Jstas]

It doesn't matter what you listen to. If your sub is drowning out the rest of your stereo, your system is unbalanced. Either turn up the gain on the full-range speakers to match or turn down the gain on the sub amp to match the full-range.

Different recordings can have variances. I have the same song by the Eagles on two different CD's. One was recorded in the early 90's, the other was recorded from masters made in the late 70's. The early 90's recording was much more robust so the volume levels were high but the song was still balanced on the stereo.

Different kinds of music will have different characteristics but, one aspect should not over-power the others anymore than the producer of the album intended it to. If you are turning your volume up halfway and hitting ear bleeding levels and having your sub over-power everything else then I will venture to say that you have your gain settings set too high. You should not be hitting peak, distortion-free performance anywhere before 75% of full volume at the minimum. A much more reasonable figure is about 90% of full volume.