So how does this combination "sound" to you

PoweredByDodge · December 2003

--- aced my final

... we had to flip coins to determine what project we'd have to build... i flipped "bandpass network" and i just about laughed myself silly... build a bandbass crossver network with a highpass for 20 hertz and a lowpass of 20,000 hertz. then run a wave generator though it and prove it works on the o-scope. with **** **** parts i still got it to about 19.5 and 20,000 on the dot. ----

as far as percentages of volume level -- i'll concur with that but with the limitation that this is pre-clip volume... my headunit's rca preouts distort/clip at 23... the deck goes up to 35 though... but its all clipped out and ****... i've tested and tested and screwed with and done everything - but tried and true.. that's what it does.

i've got the gains set so that i get my "totally highest loudness that i want to listen to normally" at about 19/20 ... 21 and 22 are for pissing of the neighbors, pickin up chicks, or other nefarious stupidity. 23 is for when i'm in a bad mood and have been drinking a lot.

24 ... 24 is like that scene in ghostbusters.... "dont cross the streams" "why?, what'll happen" "just trust me, it'll be bad."

as far as 150 watts being enough... in a standard cab pickup -- ehhh... maybe. prolly... ya. in an X-cab.. more like 200 - 250 .... and i'm not talking rap, i'm talking like just making some Bruce Springsteen sound right.

oh that note -- the friggin **** died in the old man's truck and I dunno why... sub works, right side speakers work -- left side speakers dont... wtf... now i gotta go venture into the cold and figure that one out.

MacLeod · December 2003

24 ... 24 is like that scene in ghostbusters.... "dont cross the streams" "why?, what'll happen" "just trust me, it'll be bad."

LOL!!!! Thats too good!

I used the ole "turn your volume to 3/4 and then turn up your gain til you hear distortion then back down a tad and there ya go" method to set my gains. Then I set my sub gain a smidge higher than that. That seems to work pretty good. At that level my rig doesnt distort til 30-32 depending on the recording.

I didnt mean to imply that 140 watts is all you need just that if budget or space constraints are a concern, you dont absolutley have to have the 1000 watts back there. I built a budget system to hold me over the year or two it would take to put my "dream" system together so I opted for the $110 Alpine amp.

However I am designing a hi end system for my Ram and am planning on no more than 300 rms to the sub (which Ive not decided on yet).

Systems · December 2003

theres no reason to provide an external amplifier for your rear speakers, it will set your imaging off balence. Get a HU with an internal amp to power them.

DEF lose the JL sub and box. You cant just put any sub in the box and expect them to perform as well though, as JL designs those boxes specifically for the sub it is loaded with.

It would work though.

ilikeboyz · December 2003

Originally posted by DJ Kontakt
You cant just put any sub in the box and expect them to perform as well though, as JL designs those boxes specifically for the sub it is loaded with.

It would work though.

actually....it is just an enclosure...no magic inside it;) ...if we caqn get the exact measurements...and it is built up to par...it can have many uses

Jstas · December 2003

Go back and read the WHOLE thread this time and you will see that this has already been covered in detail. There were several solutions presented and the whole reason that the Stealthbox was chosen was space requirments. Not everyone devotes all available space to the holy grail of audio nor can they afford to. Budget and utility requirements are just as important as sound stage, power levels and volume.

Systems · December 2003

Originally posted by Jstas
Go back and read the WHOLE thread this time and you will see that this has already been covered in detail. There were several solutions presented and the whole reason that the Stealthbox was chosen was space requirments. Not everyone devotes all available space to the holy grail of audio nor can they afford to. Budget and utility requirements are just as important as sound stage, power levels and volume.

wtf man I was just giving support to the solution that I agreed with the most. Maybe that extry yes will help him decide.

go help yourself and rewire your car or something

Jstas · December 2003

That wasn't directed at you. If you took it that way, I'm sorry.

Systems · December 2003

ohh ok. sorry then. lol just used to all the flaming :P

MacLeod · December 2003

As far as an amp for your rear speakers, I like using one although I use and recommend a 4 channel. This way you can adjust the gain so the rear output is less than the front. This way youre asured of good clean sound all around and still have the imaging toward the front.

And Im with ya on the space issue. Im having that same problem with my system. Im using the middle section under my rear seat for amps and the drivers side for tools and other stuff. The passenger side is reserved for my sub but its awful small. My first try at a custom fit box was .3 cubic ft and Im not real happy with it. Im going to try to figure out how to get around .55 or .6 and port it but due to my rather...shall we say..."humble" carpentry skills I may be forced to pay for my local shop to make me a fiberglass enclosure.

Jethro · December 2003

Originally posted by 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.

If you paid good money for the Stealthbox, leave the JL sub in there. It has more Xmax than the GXR or the MM2124 (11.8mm for the JL vs 9.5mm for the MM2124), and will have a lower Qtc in 1.25 cf (.83 for the JL vs. .87 Qtc for the MM2124).

Don't waste amplifier power on rear fill. Run them off of deck power so that you can fade them out completely when you have no passengers. Multiple sound source producing the same frequencies from different locations inside a vehicle will only degrade your sound stage and your image.

Jstas · December 2003

See, this is a perfect example of what I hate about car audio salesmen and most other car audio forums. Why don't you listen to what he WANTS rather than trying to convince him that what you like is what he likes? If he wants rear speakers amplified, let him have rear speakers amplified. If he wants to replace the JL sub, let him replace the JL sub. There is nothing wrong with what he wants to do. It fits his needs and desires and he seems pleased with his plan. In my book, that would be called a happy customer!

On top of that, you have done him a dis-service. He is obviously a novice to car audio and you have thrown some technical jargon at him that he may not understand. Why don't you explain to him what Xmax and Qtc mean? If you educate him, he will be able to make a more informed decision.

MrDHEJ · December 2003

It's all ok guys. Yes i'm fairly new and learning fast. I thank you all for your help, even if it's bad help.

One reason i don't want the JL sub in the stealth box, is mainly it's not Polk. I know how the Polks sound, and i doubt they have better SQ then the JL's. Maybe there not as loud, but i'm not looking for Db here, i'm after SQ. That's why theres going to be $1400 in US Amps in there as well.

As far as running an amp on the rear MMC460. There rated at 50w cont, 100max. My DEH-P77DH only puts out 22rms, and when cranked i'm afraid i'll end up cliping the rears if there un-ampd.

The USA-400 is rated at 50w at 4ohm, and if they are to loud i can always turn the gain down, or use the decks fader. Either way, they need to be ampd or there not going to sound right, and may get damaged.

Jstas, i hate salesmen. I would rather a tech tell me not to use something then explain why. It's not about what i want as far as products, it's what products i need to get what i want.

balls to the wall it's all about SQ. I gave the wife an early xmas preset and put her Polk MMC650's in the rear deck of her Maxima. My gawd i forgot just how good Polks sound. and that's with deck power. She has no idea she's getting a TU-4360.

Anyway, theres no need to flame or anything, we all can't know everything. I'm sure your all very knowlagable, but i'm also sure were all wrong sometimes. It's like Jstas said, if you know why one spekers is better then the other tell me why, then tell me the pros and cons.

Thanks guys.

MacLeod · December 2003

Hey, I admit Ive not read this entire thread cause Im lazy so this may be old news....but have you thought of a box from Qforms or Obscom? they are around $200 which is a lot cheaper than the $500 Stealthbox. They make one for my Ram that houses a single 10 and fits as well as the Stealthbox at half the price.

Ive never used one so I dont know much about em. Just thought you might want to give em a look see.....that is unless you guys have already discussed this at length! Oops

MrDHEJ · December 2003

MacLeod: Do you have there website? i havn't bought the stealthbox yet.

MacLeod · December 2003

Try Crutchfield. They carry all of Qforms stuff. Ive got their as well as Obscoms website here somewhere and Ill post it when I get it. Go to www.crutchfield.com tho 'cause you can look up the exact vehicle specific box and get a price as well.

MacLeod · December 2003

www.qlogic.ws/2003/home/ This is Q Logics site.

www.obcon.com This is Obcons.

MrDHEJ · December 2003

Well, they list a Q-logic that fits my truck, but i don't like how it looks, and it's to small in volume for the polk subs.

Easier to fill a large box, then make a small box bigger.

I like how the stealthbox is carpeted.

MacLeod · December 2003

Circuit City can get you these things as well as most car stereo shops if you dont want to buy online.

PoweredByDodge · December 2003

do not - under any circumstances - buy a plastic box for your subwoofer.

i had an mtx thunderform for my ram back in teh day... its tthe same material that Q logic uses for its Q forms...

plastic... no good at all.

it'll flex and bend.. and its bad.

JL however uses fiberglass and what not -- and that's good... that's perfectly fine and just as good as a well built wooden box.

i would highly recc the stealth box over anything else (unless you get a little wooden box made to fit and carpeted and look nice and **** - then that's fine too).

anyway... head unit power is not full bandwidth usually... often its hacked off with low response and peaky here and there... not to mention that its horribly distorted and often more mechanical sounding than anything else you'll ever here (sorry i stole u're "mechanical" term Jstas, but it applies here).

I respect a man who wants to amp his rears -- it shows attention to detail.

rear fill is often essential... some people dont require it.. dont want it.. whatever... but i found that in a decent sized vehicle - such as an x cab pickup - you need SOMETHIGN... even if its only 1/4 to 1/5th of hte power of your front speakers... but SOMETHING to fill up the rear.

anyway -- that's my two cents...

find a polk sub with proper air spacing -- throw it in the stealth box... throw a shitload of power on it... amp up the fronts and rears as you had planned and go to town -- you didn't do a bad job for a "newbie" dude... you seem like you may not know the tech, but you certainly have the general idea down and you've got an attention to quality of the system and pleasure of listening to it.

dont get distracted.

MacLeod · December 2003

Yeah, I wasnt sure about those Q Logic but thought they were worth a look see. Ive never tried one and dont know anybody who has. Well now that I think about it that alone should have been evidence they aint all that.

MrDHEJ · December 2003

I talked to one of my friends here in town that used to do custom radio installations a few years ago, and he suggest instead of getting the stealth box we make one that will be suited for the polk M124 with a volume of 0.88 feet. It'll take up less space and he already has all the stuff to make one. so that should save me about $350 and will comform better to my truck.

Is the 0.88 cubic feet with or without the speaker in it?

MacLeod · December 2003

I think that sounds like a good idea. Especially if you got a pro handy that can give you a hand. You can build your own box for under $75. A sheet of 3/4 MDF is $20, wood glue and sealer is about $7, screws are $2, jigsaw for $20 and you can get a sheet of carpet from your local shop for $5. The hardest part is doing all the math and designing the box but once that is done, and if youre have some skills with a saw, it shouldnt be a big undertaking.

I used MTX's website when I built mine. It has a lot of good info you should know before you start building or even designing. And seeing as how this was my first attempt at building a box (I got cheap) it was very uselful to me.

sntnsupermen131 · December 2003

you need to build the box to .88, displacement of the sub has been accounted for
agreed on the q-logic boxes, they "q-ring" sucks ****, it leaks air, which could cause damage to your sub, well, maybe not that one cuz i think you can use it in ported boxes, but it might, and you might get some hissing noises where the air comes out
have fun building the box and good luck
when ur making ur measurements, be sure to take into account that the wood is 3/4" think if your using 3/4" MDF, which is what i use, if you use particle board, youll blow it to pieces
-Cody

MrDHEJ · December 2003

We both have fabrication experience, and we both have the tools to do it. I just got to go get a sheet of 3/4" MDF and some carpet to match my truck.

The math is no big deal, Excel spreadsheets make it easy to change deminsions on the fly and have it caculate the volume.

The USA-600x and Polk MM124 is on it's way. I still need to get the power wire and i'm going to have the inside sprayed with Rhino Lining for sound dampening.

It's going to kill me having to wait to get all this done, but i'm sure the wait will be worth it.

PoweredByDodge · December 2003

if you dont mind spending twice as much money on wood (30 instead of 15) ... get a sheet of 3/4" birch plywood cabinet grade material --- the box will last 300 years

sturdy stuff... but mdf is fine too

Jethro · December 2003

Originally posted by Jstas
Why don't you listen to what he WANTS rather than trying to convince him that what you like is what he likes? If he wants rear speakers amplified, let him have rear speakers amplified. If he wants to replace the JL sub, let him replace the JL sub. There is nothing wrong with what he wants to do. It fits his needs and desires and he seems pleased with his plan. In my book, that would be called a happy customer!

My response was directed at this part of the original post:

Originally posted by MrDHEJ
How good do you think this combination would be in terms of SQ?

I was offering advice on how to get the best possible SQ out of his system. Your suggestion of replacing a very capable JL driver with lesser Polk drivers would achieve the opposite result.

Originally posted by 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.

The JL 12W3v2 will handle more power than a GNX, GXR, or MM2124. The greater excursion capabilities (Xmax) also mean reduced distortion. As a sub gets closer Xmax, distortion increases due to compliance loss (suspension gets stiffer) and decreased motor strength.

It is not just a matter of output, but a matter of reduced distortion at realistic listening levels.

Jethro · December 2003

Originally posted by MrDHEJ
One reason i don't want the JL sub in the stealth box, is mainly it's not Polk. I know how the Polks sound, and i doubt they have better SQ then the JL's. Maybe there not as loud, but i'm not looking for Db here, i'm after SQ. That's why theres going to be $1400 in US Amps in there as well.

As far as running an amp on the rear MMC460. There rated at 50w cont, 100max. My DEH-P77DH only puts out 22rms, and when cranked i'm afraid i'll end up cliping the rears if there un-ampd.

The USA-400 is rated at 50w at 4ohm, and if they are to loud i can always turn the gain down, or use the decks fader. Either way, they need to be ampd or there not going to sound right, and may get damaged.

Jstas, i hate salesmen. I would rather a tech tell me not to use something then explain why. It's not about what i want as far as products, it's what products i need to get what i want.

balls to the wall it's all about SQ.

Fair enough. It was just a suggestion. I am sorry if I confused you at all by using terminology that you were not familiar with.

Here is a site that explains Qtc:
Sealed Speaker Enclosure Design

Here are the MM124's Vas, Fs, and Qts values:
MM124

To convert liters to cu ft, divide Crutchfield's spec by 28.32. Here is a calculator to determine the Qtc of a given enclosure:

Qtc Calculator

I see you have decided on the MM124 - an excellent choice. But, if you are truly "balls to the wall it's all about SQ", you may want to put that driver in a slightly larger box than .88 cu ft. You will find that 1.25 cu ft or even larger will give you a little better low-end and a little less upper bass empasis.

Again, just a suggestion for maximum SQ. If you are already set on .88 cu ft, just stuff with polyfill and you should be good.

sntnsupermen131 · December 2003

Jethro, wouldnt by increasing the box size the SQ go down
im wondering because if it has more air, the sub can not control itself as well b/c its "backbone" is not supportive enough?
-Cody

MrDHEJ · December 2003

Now, in regards to using birch plywood for a box, back when i started messing with car audio i did some research and found that you SHOULDN'T use playwood, or other hardwoods. If i remember corrctly, it was because the harder material would resonate and sound crappy. Has this changed?

The information here on the Polk site in regards to box volume states: A smaller box will require more power, but produce tighter bass in the whole spectrum, where as a larger volume box will focus more on the lower freq. and be more boomy and louder at a sacrifice to the higher bass freq., but require less power.

PoweredByDodge · December 2003

yes u are correct -- almost all plywoods SUCK.

plywood is "grainey" with knots and other junk... and its generally not very dense at all... and it will resonate...

but baltic birch cabinet grade plywood that's 30 - 35 bucks a sheet is not... this type of wood tends to be very dense... as dense if not more dense than MDF. also... it is amazingly rigid... i would say twice as rigid as MDF (maybe not twice, but look at it this way... if you had a 2000 watt sub that required 1" MDF, you could build the box for it that would be just as good as the 1" MDF box out of 3/4" birch ply that i spoke of).

I've used birch ply for three boxes now and in my opinion it totally obliterates the MDF boxes i've built before. it holds up so much better, is so much stronger, and the screws do not split the wood nearly as much as they tend to split the MDF (and yes that is predrilled MDF -- splits anyway).

Thom, the polk installer dude, said he swears by cabinet grade plywood -- I had intially told him and Jstas they were "fulla it"... but after trying it out for myself on a whim I found them to be nothing but absolutely right.

They suggest using cabinet grade ply with liquid nails and a brad nailer... however since i dont have a brad nailer (hammer wont work) I predrill and use drywall screws with either a foam thin gasket between all joints or some heavy duty silicone between joints (messy but it works) -- then seal all internal corners with a good bead of silicone (for either MDF or ply -- u need the seal inside).

if you want a better explaination of why this works the way it does - i would hope that Jstas can give you that... I really don't much understand what it is about the two wood types that makes one kick the **** out of the other... nor what properties of a good cabinet grade wood make it as dense and more rigid than MDF, but he has more of a good idea why -- sadly in this area I am left with no better explaination than "cuz it is" -- which is a really **** explaination, but none the less the honest truth.

So how does this combination "sound" to you

Comments