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Discussion Starter #1
I'm considering the following audio modifications to my car:
  • JVC KD-NX5000 (w/ Sirius, Bluetooth, i-Pod connector and backup camera)
  • JL Audio Stealthbox (Lotus Elise version)
  • JL Audio TR400CXi (front speakers)
  • JL Audio TR525-CXi (rear speakers)

I'm assuming the subwoofer goes to 80Hz or above, in which case the 4" JL Audio speakers have a frequency response from 71Hz to +22KHz. +/-3dB. this is the system JL Audio recommends for the Elise. Assuming JL Audio is using one of the conventional roll-off rates on their speakers, there shouldn't be any hole in the frequency response, and since ~80Hz and below is omnidirectional there won't be sound directivity issues with the subwoofer location.

I'm not sure about other issues though, such as whether the JVC KD-NX5000 has sufficient amplifier power to drive the front and back speakers. I'm familiar with home audio and if car audio isn't much different, then the setup should be perfectly fine unless I turn it up louder than a certain volume. The problem is, I don't know how that translates into volume inside a car. I'm also concerned with possible low Ohm issues, causing the speakers to draw too much power

This leads me to the following questions:
  • Will I get sufficient volume and distortion free audio with this setup, especially if I want to listen to music with the top off of the car sometimes?
  • Would I be better off adding a separate 4 channel car amp with more power (likely JL Audio as well)?
  • Is all of this work, including a separate amp and backup camera as well as everything else, going to require any drilling into the car anywhere, or can it all be done without being invasive?
  • Is a separate device required, such as the above mentioned 4 channel amp, to handle crossover concerns between the components?
  • If a crossover is required, how does the 4 channel amp setup accommodate a subwoofer output?

I guess I can always try it out. The system should give sufficient power at low levels at least, and I can test out how loud it goes before distortion occurs, but if anyone has already been there and done it, it would be easier to get it all done in one shot. I'm also curious enough about all of this to set up ETF 5 and a mic in the car, at the driver's seat, to measure the frequency response via the auxiliary input jack and see if there are any egregious anomalies in the response.

This leads to one final question (for now at least... :evil:):

  • If there are problems in the frequency response, what do people recommend I use to fix those issues (beyond simple EQ)?

Thanks for any input.
 

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have you taken delivery of your car yet? and if so, have you driven it?
 

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Discussion Starter #3
Thanks for your input. Next...
 

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  • Will I get sufficient volume and distortion free audio with this setup, especially if I want to listen to music with the top off of the car sometimes?
  • Would I be better off adding a separate 4 channel car amp with more power (likely JL Audio as well)?
  • Is all of this work, including a separate amp and backup camera as well as everything else, going to require any drilling into the car anywhere, or can it all be done without being invasive?
  • Is a separate device required, such as the above mentioned 4 channel amp, to handle crossover concerns between the components?
  • If a crossover is required, how does the 4 channel amp setup accommodate a subwoofer output?
The JVC head unit is only 20W/channel. That's not nearly enough... and you'll need >100W to drive the JL Stealthbox. So I'd say you definitely need an amp. Check out Alpine's PDX-5, it's got four 75W channels and one 300W channel, it's small enough to fit in the package tray behind the back seat, and it's got built-in crossovers and level controls.

I did a similar install (but with a PDX-4.150, the PDX-5 wasn't out yet).
 

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Discussion Starter #5
The JVC head unit is only 20W/channel. That's not nearly enough... and you'll need >100W to drive the JL Stealthbox. So I'd say you definitely need an amp. Check out Alpine's PDX-5, it's got four 75W channels and one 300W channel, it's small enough to fit in the package tray behind the back seat, and it's got built-in crossovers and level controls.

I did a similar install (but with a PDX-4.150, the PDX-5 wasn't out yet).
I thought the Stealthbox had a built in 300W amp. I misread the web page. Oops. That certainly changes everything. Thanks.

I'm putting that Alpine unit on my short list...
 

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I think Ace's point is that the car's so noisy, there's no point in stressing too much about getting the perfect sound system - none will sound very good in these cars.

I'm running a stealthbox off a small Blaupunkt amp, with Polk speakers replacing the stock ones and still run off the head unit. It sounds great and is a simple, relatively lightweight solution. Upgrading speakers alone didn't make much difference IMO, what really did it was adding the subwoofer.
 

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I think Ace's point is that the car's so noisy, there's no point in stressing too much about getting the perfect sound system - none will sound very good in these cars.

I'm running a stealthbox off a small Blaupunkt amp, with Polk speakers replacing the stock ones and still run off the head unit. It sounds great and is a simple, relatively lightweight solution. Upgrading speakers alone didn't make much difference IMO, what really did it was adding the subwoofer.
+1
The sub made the biggest difference. The Alpine amp weighs <7lbs... a little more than a gallon of gasoline, less than a gallon of water.
 

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I think Ace's point is that the car's so noisy, there's no point in stressing too much about getting the perfect sound system - none will sound very good in these cars.

I'm running a stealthbox off a small Blaupunkt amp, with Polk speakers replacing the stock ones and still run off the head unit. It sounds great and is a simple, relatively lightweight solution. Upgrading speakers alone didn't make much difference IMO, what really did it was adding the subwoofer.
I can second this opinion. I have the stealthbox, stock Alpine head unit, Boston 4ch amp, and Alpine components (4" front, 5.25" rear). The components are wired in parallel off 2 channels and the other 2 channels bridged for the sub.

Plenty of volume, which is necessary to overcome road noise (and exhaust noise in my case) but not really hifi. Just like home audio, the *environment* is everything.

Often, the stereo is off because the sound of the car is better, IMHO.

WW
 

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Discussion Starter #9
I think Ace's point is that the car's so noisy, there's no point in stressing too much about getting the perfect sound system - none will sound very good in these cars.
I've had a 2005 Elise with stage 2 exhaust for ~3 years. I know what you mean. I appreciate the concerns and I am aware of what I am getting into.

If you look up what I am buying, the items I chose are nowhere near top end components. They are rather cheap components (except the sub, the head unit, which I need anyway for the rear-view camera as extra protection so I don't run over my kids backing out of the garage, and an amp). I'm not looking to build a perfect sound system, and I never said that was my objective. My objective is to figure out what extra components I will need to make this setup work well enough to play it loud (with the top off) and to have a relatively flat frequency response...

If I want perfection, I'll listen to music in my dedicated, and finely tuned, HT/listening room. ;)

I'm running a stealthbox off a small Blaupunkt amp, with Polk speakers replacing the stock ones and still run off the head unit. It sounds great and is a simple, relatively lightweight solution. Upgrading speakers alone didn't make much difference IMO, what really did it was adding the subwoofer.
I've been considering the Polk and Infinity speakers as alternatives if the JL Audio tweeters don't have any range of motion. I don't want component speakers due to separate tweeters, but I do want to be able to slightly adjust the tweeters, in order to adjust the directivity of the high frequency reflections bouncing off the car windshield (if this ends up being necessary). They are all around the same price range.

It would be great if I could run the sub off the same head unit though, as adding an amp turns this into much more work. The problem is, I want to put a backup camera in the system, because I have three kids, some of which could run into the driveway when I pull out of the garage (better to be safe than sorry if by some chance they manage to sneak out into the driveway while no one is looking...). I wouldn't mind the navigation system, HD storage, Sirius (for Howard Stern and the Grateful Dead station), and Bluetooth either.

I guess if wiring has to be done for the backup camera, it isn't such a big deal to do the rest of the stuff at the same time... I just don't want to be unnecessarily invasive to the interior of the car if possible.
 

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Q.C. -

You simply CANNOT run the sub from the headunit. Sort of like running your HT mains from you iPod.

WW
 

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Discussion Starter #11 (Edited)
At this point, as I mentioned, the whole thing is still just a consideration. The head unit is a definite, as well as the extras for it (Sirius, Bluetooth, license plate rear-view camera).

To be honest, where I have been waffling, is on whether I want to add the extra weight of the sub. Now, adding a sub and an amp is even more weight. At what point do you lose the 0-60 in 4.0 seconds (I realize every lb counts)? I don't even like having another person in the car because it has such a profound effect on performance...

If I do add the sub and amps though, I would like to speaker match them. As I'm sure the JL Audio "boss" put some effort into maximizing his setup by matching speakers well (the ones they recommend on the Stealthbox web page).
 

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Discussion Starter #12
Q.C. -

You simply CANNOT run the sub from the headunit. Sort of like running your HT mains from you iPod.

WW
Yeah, I realize that. I thought the specifications on their website said that the sub has a built in amplifier (in the HT field, most of them do nowadays...).
 

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My solution was to shove one of these in the footwell. Fits perfect and I can have the whole thing out in 5 minutes and very little weight gain. Not going to win any sound contests but it does the job. I also replaced the hu and speakers too. All of it combined made my system as good as it needs to be.

I am pretty happy with my setup - Pioneer P6000UB, Eclipse 4" and 5.25" speakers, Ipod Nano, and the sub listed. Cheap and simple.

JVC CS-BB2 Compact powered subwoofer at Crutchfield.com
 

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Discussion Starter #14
My solution was to shove one of these in the footwell. Fits perfect and I can have the whole thing out in 5 minutes and very little weight gain. Not going to win any sound contests but it does the job. I also replaced the hu and speakers too. All of it combined made my system as good as it needs to be.

I am pretty happy with my setup - Pioneer P6000UB, Eclipse 4" and 5.25" speakers, Ipod Nano, and the sub listed. Cheap and simple.

JVC CS-BB2 Compact powered subwoofer at Crutchfield.com
Nice, thanks for the link.
 

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At this point, as I mentioned, the whole thing is still just a consideration. The head unit is a definite, as well as the extras for it (Sirius, Bluetooth, license plate rear-view camera).

To be honest, where I have been waffling, is on whether I want to add the extra weight of the sub. Now, adding a sub and an amp is even more weight. At what point do you lose the 0-60 in 4.0 seconds (I realize every lb counts)? I don't even like having another person in the car because it has such a profound affect on performance...

If I do add the sub and amps though, I would like to speaker match them. As I'm sure the JL Audio "boss" put some effort into maximizing his setup by matching speakers well (the ones they recommend on the Stealthbox web page).

Easy fix. S/C, pulley, tune, etc.

BTW - didn't catch whether you had an Elise or Exige?


WW
 

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Put the 5.25's in the front. Do a search for "speaker rings". I think the maker/seller is named jim-clayton. Put fiberfill under the fronts when you install them - it makes a big difference because the sound really reverbs with all the plastic/metal in the dash.

Put some 6.5's in the rear. I went with Polk DB651S which are slim mount and go in there with no mods necessary.

We also have a Kenwood enclosed amp behind the pass seat which is a dog, but does help. Your sub should be much better.

We're using a high end pioneer HU, can't think of the model #.

THe folks who say the sound has to suck, just haven't done it right. You're never going to make it a Lexus, but I just drove ~100mph for 3 hours with the top off and a Stage 2 and I heard the music great.

Once you get the equipment in there, you need to make profiles for top off/soft top/hard top and program them in.

IMO, the biggest improvements come from getting the biggest speakers possible in the front and rear. I can't stress that enough. Putting the JL5.25's in the front made an enormous difference for us.
 

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I'm not sure what you mean. :huh:
My point is simply that adding ~ 40 lbs of audio gear likely won't change the outright performance much (a diet and exercise can correct this for some) and if so, extra HP is simply a modification away :evil:

WW
 

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Discussion Starter #19
My point is simply that adding ~ 40 lbs of audio gear likely won't change the outright performance much (a diet and exercise can correct this for some) and if so, extra HP is simply a modification away :evil:

WW
It is true on the one hand that losing personal weight and lightening other gear on the car will make up for the additional added weight due to a sub and amp, but on the other hand, it would be even lighter still without the sub and amp. :p

Has anyone gotten the Exige S 240 below 0-60 in 4.0 s with all the carbon fiber mods, and other mods, out there? Any good threads on that topic around? Thanks.
 

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Not sure...and to be frank...doesn't really matter. I know the car is a lot faster than I am capable of at this stage, and I figure I'm just over stock weight with my mods (some add, some subtract) and I have the Gotham tune and a smaller pulley, lighter exhaust, etc. that makes more power...at the track yesterday I learned first hand just how many additional mods the DRIVER needs!

WW
 
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