Parcel-shelf in a Legnum ?

[WizardKing]

I know, parcel-shelves are for hatchbacks, not estates. After experimenting with a single cabinet ;
30781

. . . it was deemed necessary to have a very large cabinet to house 4 x 12" subwoofers. So now, the boot is the large cabinet.

30782

30783

30784

30785
Initial testing has shown just over 120 decibels . . . not too bad for a hotchpotch of parts I've collated over the last decade.

[peter thomson]

pics aren't working

[MarkSanne]

You can't embed external pics on here. Use the forums uploader or plain links like this:
http://i12.photobucket.com/albums/a218/wizking/CIMG0167-1.jpg
http://i12.photobucket.com/albums/a218/wizking/CIMG0178.jpg
http://i12.photobucket.com/albums/a218/wizking/CIMG0179-1.jpg
http://i12.photobucket.com/albums/a218/wizking/CIMG0180.jpg
http://i12.photobucket.com/albums/a218/wizking/CIMG0181-1.jpg

[wintertidenz]

Are they open-air subs? If they aren't then that would explain the low dB score - unless your boot is really well sealed it will leak like crazy and affect the subs.

Good job on the parcel tray though.

[Ghost_2008]

The two centre subs look to be 10" Fly traps? if they are they should be in a completely sealed unit........ if you go on line you should be able to find a diagrame for what should work best for you....... but I have one flytrap in the boot and it's all you really need, unless your looking to deafen yourself.......

[Davezj]

yep, pic don't work from the first post.

[WizardKing]

Sorry about that, pictures now working but no idea what the multiple 'attach's' are from.

[elnevio]

Sorry about that, pictures now working but no idea what the multiple 'attach's' are from.
It's a bug that appeared when we changed servers, but should hopefully be fixed when we are eventually able to upgrade vBulletin without killing the forums! :computer:

[WizardKing]

The centre 2 are 12" Fly's. They were originally housed in their own amplified, sealed enclosures. They sounded horrible, too. I believe their amp wasn't too clever but not as deterimental as the under-sized cabinet to their output.

I've heard it mentioned for years that rubber-surrounded subs require a sealed enclosure to perform correctly. My experiments have always yielded the same results, i.e. bigger is better for enclosure size. The only measurement used here was, big boot = 4 x 12" needed !

Low dB count ? 120 is big, isn't it ?

[wintertidenz]

Unless the subs are specifically designed to be open air, they should be in a box designed for their requirements. Subs that aren't open air can actually damage themselves due to over-excursion, as they have nothing to support them behind - just a massive amount of air in a leaky box.
The air inside the box will support the spiders etc, and provide that compression of air which will help the sub make more sound and respond quicker - result: punchier bass.
Try putting one sub in a box and the other open-air then play some fast bass through it (kick-drums are great for this) - you should be able to notice the sloppiness of the open-air sub.

There is a few programs around for sub box design if you have the sub parameters - a free one is WinISD. There is a paid one called Bass Box Pro, which is great - not sure if there is a demo of it.

I've managed 128 dB with a single 10" sub in a sedan. Suspect my current setup with 2 12" subs would be mid 130's, my girlfriend's hatchback would be low 140's with a single 12" sub and around 300w RMS.
My friend has cracked 147ish in a hatchback with about 2000w and a 12" sub :D

[VR457]

Agree on all the points with the above comment: You will not get the performance unless the subs are sealed into a box properly. All subs also need to be same make and model as performances can and do vary. Otherwise you will end up with certain frequencies effectively disappearing.

It is possible to seal / sound deaden a boot completely and this will work if no air pressure can leak out. Mostly useful for sedan / saloon cars with metal rear shelves.

I have BassBoxPro 6. Whizz across the sub make and model number and should be able to give you an idea of enclosure size required. Would be handy to know what type of bass you like mostly - rolling drum and bass, punchy house, or mixed hip hop / r&b.

With 4 x 12" and around 800wrms it should be possible to get near enough to 140db.

[WizardKing]

wintertidenz,
some impressive figures there, every credit.

VR457,
I have 2 x JBL GT4-12 and 2 x Fli 12 Trap speakers. Musically, I encompass The Carpenters and Tchaikovsky through to Whitesnake, although I'd say punchy house predominantly.


I should've perhaps mentioned earlier, I do understand that I'll never obtain the most from my setup. Compromises have to be expected when boot-space is needed regularly (for another hobby, racing toy, nitro-cars !) Having a large enclosure would mean leaving it at home when travelling, defeating the purpose of itself.
That said, it would be good to know where I should be at. . . maybe I can re-work my present setup.

[VR457]

Im having similar problems trying to design a box for 2 x 15" subs with the ability to get at the spare wheel and all my tools as well as accommodate an amp that looks like a small sub box on its own!

You can find a way if you must to build a box just because it wins hands down over a free air setup. Listen to the cannon sound on 1812 Overture (?) on a good setup! You can mount a box on the shelf but it will be hard.

The last ditch compromise would be to keep the shelf design but also use a variable subsonic filter on an amp or an independent crossover set to filter out 20-25hz and lower signals.

Correct amp setup is a must to get the best performance. The 'Gods' of TalkAudio would have you use an oscilloscope as a minimum but a bog standard multimeter with an idea of the amps proper RMS rating can get you fairly close.

And sound deadening. Cannnot stress enough how much you need this stuff. Its fairly pricey, weighs a ton, is a pain to apply to all the panels but definetely worth the fact that it will keep all the bass in the car and not rattle like a mofo. Unless you like driving past young girls shouting random stuff.

[WizardKing]

I have an oscilloscope, just no idea how to use it !

[Turbo_Steve]

I'm going to be brutally honest here: 120dB is ridiculous. You are definitely causing yourself lasting hearing damage, as well as a number of other medical factors associated with prolonged exposure to high pressure low frequencies. It's fun, but you can't do it for long.

Furthermore, you're not achieving much with all those speakers. As has been mentioned, the huge enclosure size means they are flapping about all over the place, and the fact that there are two different models, and sharing the same airspace, means the timing and phasing is going to be stupendously complicated. I don't doubt it's loud and sounds pretty cool, but here's the rub: I promise you can get 110dB out of a subwoofer mounted under the boot floor in with the spare wheel. A single sub. So you get to keep your boot, and you're not lugging around heavy stereo bits and impacting your fuel economy the whole time.


All that being said: there's some nice kit there (I don't like Kenwood much, but their crossovers are cool, and I don't mind FLI subwoofers at all, and JBLs are the mutts. The shelf is neat (though not as cool as the side-box arrangement) though I would worry that it screams "STEAL ME!".

[wintertidenz]

Steve - 120dB is actually seat thumping, but not too deafening :) 140ish really starts to mess with your head - I would recommend 135 max for a daily system. I have been told that the higher frequencies kill the hearing faster than the lowers, but I think my hearing is slightly stuffed due to headsets and screaming customers at work, so it doesn't make too much of a difference to me!


What I would suggest is putting one sub in a wheel well sub enclosure - that will give you some very good volume.

However, if you want to stick to the parcel tray idea you can use one of the sets of subs, and when the parcel tray is made put some heavy rubber stripping in the gaps - this will help to eliminate some of the leaking. Also a suggestion is to build a slightly recessed shelf and get some speaker cloth to go over the subs to cover them - leave about an inch of space between the cloth and the sub so it doesn't interfere with the sub excursion.
With the parcel tray - you are going to have issues with the surfaces within the boot as well, they are not particularly good. MDF is used because it can take some flexing while still sealing properly, and is kinder to the acoustics. Putting items in the boot will also change the volume of the box, and if they are fragile things - the subs may pound them to pieces! Small items can also get into the spiders and other working parts of the subs, which can have disastrous results.

Also have a look at building a smallish box that integrates into the side of the boot - I think there is a thread in this forum :)

[Turbo_Steve]

120db at 1m is sufficient to cause breathing difficulties at frequencies below 100Hz.

Anything else is psycho-acoustics. Higher frequencies will do more long term damage to your hearing, but large volumes of sub-bass will also degrade that frequency band (and quicker than you think, and with no noticeable pain compared to a higher frequency at the same gain).

Nobody in their right mind really needs more than 120dB of audio in a car.

Bear in mind that the safety limit imposed on most venue systems is between 130-135dB.

[Ryan]

Agree with Steve, 120Db is stupidly loud :speechles

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[WizardKing]

Done the speaker mesh one in my previous car, stealthy. Planning to do the same again when I've chance to pick some new material up.

Rubber sealing-
similar done already, using expanded-polystyrene tube (pipe-lagging) with carpet over top.

At times, the enclosure isn't under-damped, depends what's in the boot !
I still maintain that most sub enclosures are too small for my preferences. Yes, they'll give a 'tighter' bass, however, they trade that for the 'big' sound obtained from larger enclosures.

I can't believe there's so much disdain for power, especially on this forum. Why do you own VR4's when 70HP is enough to drive around with ??

Or maybe it's good to have the power at your disposal and every now and then treat yourself to some speed/volume, 'cos you can ?? . . . meanwhile taking it easy with quality.

[wintertidenz]

Ahh, right, you have already sorted that stuff out - apologies for not seeing that before :)

Try it with the two subs and see how you go - the parcel tray is actually a nice idea particularly as you are using some previously unusable space.

Again, kudos to you for an interesting idea :D


Power in car audio is a bit of an argumentive point. Some people say you need a lot, where others don't. Some power in reserve is always good - but personally I will trade power for sound quality to a certain extent.
At the end of the day, if you have a clean unclipped signal coming into your gear with a bit of headroom, your gear will last longer as long as it is not being fed waaaaaay more power than it can handle.
An example is my old 10" sub - 350w RMS, 800w max. I was pushing it in a quarter-wave transmission line enclosure at 500w RMS with a clean unclipped signal, never had a problem with distortion or anything going pop. I was pushing heavy bass through it for 2 years and it is still as tight and clear as the day I bought it.

[WizardKing]

No worries, my fault for neglecting to mention it.

The amps are only 250W each, into 4 x 1000W coils. Obviously only peak figures, not RMS ! Although I'd like a little more power, it's a fairly reliable set up, providing it's not being pushed too far, like you said.

I'm not against all enclosures, just car ones. I've been delighted with my Tannoy Sixes that have been in my lounge for over a decade, they've powered many, many after-hours parties !!

If only I could put a set of them in my boot, all would be great.

[VR457]

I'm not against all enclosures, just car ones. I've been delighted with my Tannoy Sixes that have been in my lounge for over a decade, they've powered many, many after-hours parties !!

Home speakers are usually 8 ohm impedance. Parallel wire them and it will drop to 4 ohms, which means a car amp can run them. Might not give you the result you want though - cars are horrible acoustic environments.

[VR457]

120db at 1m is sufficient to cause breathing difficulties at frequencies below 100Hz.

Anything else is psycho-acoustics. Higher frequencies will do more long term damage to your hearing, but large volumes of sub-bass will also degrade that frequency band (and quicker than you think, and with no noticeable pain compared to a higher frequency at the same gain).

Nobody in their right mind really needs more than 120dB of audio in a car.

Bear in mind that the safety limit imposed on most venue systems is between 130-135dB.

Take it easy guys! Most of the damaging frequencies are around 1 khz, and chainsaw, aeroplane etc output at those frequencies.

If you look at Fletcher Munson acoustic graphs you will see that the human ear will need around 20 db louder at sub 100hz frequency to sound the same as a 1 khz signal. In fact, play these test tones and you will see how uncomfortable higher frequency signals are.

I made myself tone deaf in my teens by whacking the treble eq to max on a walkman. For two weeks all i could not hear any 's' sounds. As a comparison, my last install bass was 143db and was fine. i had around 1500 wrms on bass. Even so, just 200wrms midrange turned up loud was enough to get ear ringing after 5 mins. That might only have registered 125-130 db.

So, if you listening to loud rock music, you are very likely to go deaf fairly soon. However, if it's reggae and the like then 130 db won't even get you tickled. 140 db+ on bass will damage you, one guy on Talkaudio managed to loosen his retina on a 150db system!

[Turbo_Steve]

I've been involved in comissioning a variety of large PA systems of various designs and functions in the past couple of years, and you're right, in a normal environment bass isn't likely to have much impact on your hearing until the power levels roughly treble those applicable to mid and top.

However in a car, you're talking about all sorts of weird pressure differentials, and stuff. Try breathing deeply in a car with a 33Hz tone at 125dB and all will become apparent.

[wintertidenz]

I think the main thing with the car systems is that you aren't continually blasting it at full volume, hence a 135ish dB system on a Termlab test may actually be around 100-110dB at a normal listening volume. I think you would need to be fairly silly to blast the system at that volume all day every day - it would just be too loud!!!
The volume also changes according to the notes - so to get that loudest volume you would need to play that tone continuously, and anyone would be driven nuts by that...

[WizardKing]

Midrange is horrible on the ear and unhealthy for the body. It is the 'cheap' (throughout many levels) band of the human audio spectrum and where perceived volume levels reside.
Never play test-tones on audio-equipment, neither yourself nor electronics were made for the task (unless torture is the desired outcome.)
Instead, opt for audio testing music such as the awesome " Bass Test-360 Cikles" [freely downloadable http://slsaico.blogspot.com/2008/07/feb-18-illegal-competition-car-bass.html

Even better is to play whatever tunes you happen to like listening to . . . :guitarist . . . 'cos that's why you wanted to install the I.C.E. in the first place, isn't it ? /megawoot

Incidentally, regular cruising-speed is fairly noisy in a VR4, (and most other cars, I suppose, @2mpm ) isn't it ?



Errm, pay this post no mind because the preceding post, by wintertidenz, said it better ! /Banana :operator:

[Turbo_Steve]

Fair enough on the 135dB point.

I have a 4x40w headunit (so likely producing around 4x30w at best) and a 300w sub running on a 120wrms amp. It's too loud to talk over, but you could concieveably shout over it. An extra 100watts on the bass side would not go amiss, and a 4x50w amp would be more than enough for the mid/tops, but it would almost never get used: I can comfortably have panels rattling all over the car, and (as above) the midgrange is detailed and starting to get painful. The only reason I would want more power is for some additional headroom, to keep the detail as you push it a bit harder.

Using a cheap audio meter, it rates 115dB of midrange, and around 122db of bass.

I am honestly not knocking what you've achieved with the install you have, but two of those drivers in the oddments tray (with some reinforcing) should be enough to really have you bumping with the right amp and setup.

With four drivers, I'd be tempted to run two parallel pairs to get a 4ohm load on a really nice monoblock amp. I ran four MTX 10"s in a ford sierra, and it was enough to break the back window.

[WizardKing]

Nobody in their right mind really needs more than 120dB of audio in a car.




(I forgot to pick up on this point earlier, Turbo_Steve.)


That's neither a familiar state to me, nor one I've ever been falsely accused of /Banana /bananaroc

[steelie600]

ive bin in Wiz's car with a touch of pendulum beating out and we saw just nudging 124dB which was plenty loud!!! And like Steve said no one in their right mind runs about at that volume all day 100-105 dB is probably a fair number.

I personally only have my radio as background music whilst driving ie very low. But will crank it up from time to time when the feeling gets me

[VR457]

You guys obviously havent developed an addiction to sub 45hz, seat-shaking bass! Ahhhh, bliss, massage for free! 140db and its yours!

[N9nebar]

You guys obviously havent developed an addiction to sub 45hz, seat-shaking bass! Ahhhh, bliss, massage for free! 140db and its yours!
For all you audiophile and bass junkies out there ,check out BOY 8 BIT
he will put your ICE thru' its paces and you will want more. /Banana

http://www.myspace.com/boy8bit

http://www.youtube.com/watch?v=r4ilJbVsoNI&feature=rec-HM-fresh+div

Just a little sample, sounds better cranked to 11 :smartass2

[WizardKing]

A wee bit of an update to this thread ;

To accompany my new JL Audio 500/1 amplifier, a new [better quality] speaker was required.
So to change from my usual, oversized cabinet, or boot, approach ;



Rockford Fosgate P3L-S12 ;

32094

[Turbo_Steve]

It's a gorgeous piece of kit, but you seriously have more money than sense :)

[WizardKing]

What ? The other amps and speakers were all 2nd. hand purchases, made over the last decade.

Even my 'new to me' JL Audio amplifier was picked up at a good price because it's second-hand. [From this very forum, too.]

Nope, I'm not letting anyone make me feel guilty for spunking a load of dosh on totally unnecessary items. I work hard and play expensively. Lord knows, with the way my car uses fuel, I'm best off spending while I still can !
(Anyway, I stuck it on the plastic- buy now and if you don't survive the month, no worries !)

[stuey]

That looks like a proper solution for nice quality sub in a realistic narrow enclosure

[WizardKing]

Cheers. Have you seen these,
32095

Only about two and a half inches deep, you need much deeper pockets to buy them, though !

[carlos-1975]

so what does it sound like then ?
carl

[Turbo_Steve]

Unless you've got LPG, dude......Have a look at my effort. COst less than £100 for the speaker and amp.

Do you really need it louder? Put in some of your current cones.

http://www.clubvr4.com/forum/showthread.php?p=498726#post498726

[WizardKing]

Carl,

Although I've only had chance to do a quick setup, pretty good. The amp you sold me has a lot more settings than I've seen before. (Still researching all the parameters available.)


B.T.W.
I'm very pleased with my new noisy amp and quiet exhaust, cheers.

[carlos-1975]

glad your happy

[Turbo_Steve]

Those JLs are seriously tasty kit. I am deeeeply jealous :D

[wintertidenz]

Yeah they are pretty damn nice... *drools for a bit*