AdiSRI
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Registered: 1st May 02
Location: Berkshire
User status: Offline
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Currently i run 6.5" components in the front, 6x9's in rear shelf and a JL 12W3V2 sub in the boot.
The 12" sub doesnt seem to like high sub bass so much, say 80- 150 Hz, ans i have been considering getting rid of the 6x9's and building two of these:
JL 6W0
or
JL 8W0
into the rear quarters. They show a 4 ohm load to the amp and require 75w RMS each, my 4 channel amp delivers 80w RMS x 4 and i can set the crossovers on the rear channels to work with these subs.
Set up this way the 12" wud handle up to say 60Hz, the small subs 60 - 150Hz and the comps 150 + Hz
Has anyone done this and would it sound any good????
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Nick-S
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Registered: 3rd Mar 04
Location: Leigh. Drives: RS Megane 230 F1 Team R26
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Is this not in the wrong section
Shudent this b with ice
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FlamingCorsa
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Registered: 22nd Apr 03
Location: Shropshire
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my mate has 3 jl 8 w3 and the sound is AWSOME! thay are tiny but i wud say thay make more bass than anyone needs! lovely sound 2! sooo punchy!
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AdiSRI
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Registered: 1st May 02
Location: Berkshire
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i put it in ice, basically no reply lol
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AdiSRI
Member
Registered: 1st May 02
Location: Berkshire
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i am tempted by the 8w0's but they need a fair size enclosure which i dont know if i cud physically build to the back of the card!
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TOMAS
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Registered: 7th Aug 02
Location: Nottinghamshire
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Can you bandpass them with your crossover so that they can play ONLY 60 - 150Hz i.e run 150Hz Lowpass and 60Hz Highpass? Otherwise you'll be faced with some phasing issues/sound cancellation if the Lil' JL's start playing the same notes as your 12.
Ideally you want the 8W0's playing upfront IN STEREO as thats where the stage is and it might pull it a bit rear if they are in rear quaters.
TBH though it sounds as though your lacking midbass? If you had good enough 6.5" comps upfront that had PLENTY of juice thrown through them and your 12 was not set on full blast then it should sound sweet. Whats your current crossover setting for all your kit and have you tried playing around with the phasing of things as this is probably THE most common cause of weak Midbass... 
[Edited on 31-03-2004 by TOMAS]
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AdiSRI
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Registered: 1st May 02
Location: Berkshire
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I currently have alpine (cheapish LOL) comps in the front which have the LPF set at 125Hz.
I have JBL 6x9's with the LPF set at 80Hz
The 12" sub is set with subsonic at 25Hz and 80Hz cutoff.
When i listen to tunes like mj etc.. certain bass notes are very loud (due to the sub) and certain bass notes are very quiet, which makes for a basically crap sound IMO.
HELP!
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TOMAS
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Registered: 7th Aug 02
Location: Nottinghamshire
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I think you mean you run the fronts at 125 HP??
Well thats FAR too high, you want 80Hz or if youve got some REAL 6.5" comps then run them down to 60Hz highpass. That will bring the midbass upfront, which from the sounds of it you are VERY lacking!!
If I were you i'd invest in some quality 6.5" comps upfront with a lil sound dead matt around them, amp them with around 100wrms PER SIDE. Set them up to the right crossover point so that they can cope nicely with everything, then bring the sub in at 80Hz LP, unplug the 6x9's for now.
Set the fader/gain on the 6x9's VERY low so that they can JUST be heard now play around with the crossover on the 6x9's, try and run it at the same HP as the front comps p.s if your still lacking try running the sub out of phase i.e 180 degrees to the midrange drivers.
[Edited on 31-03-2004 by TOMAS]
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AdiSRI
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Registered: 1st May 02
Location: Berkshire
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im planning to remove the 6x9's in favor of the small jl subs, would this be better?
Shud i just get good comps and not have rear channel speakers at all?
The amps i have are Alpine MRD-M300 and MRV-F540...
So i should bring the HP back up on the comps to 80Hz?
The comps i have are Alpine SXS-1757's
http://www.letsbuycaraudio.com/main/?cat=speakers&make=16&product=394
I had the front comps set flat until a couple of days ago, but they dont seem to do much at all as far as bass is concerned, can you reccomend any good ones, focla polyglass??
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TOMAS
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Registered: 7th Aug 02
Location: Nottinghamshire
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Take them DOWN to 80Hz yeah, but they may not cope. Not sure how many watts they are recieving, prolly about as much as they can take but something like Focal, Boston, JL, Rainbow or Diamond Components would give you something good and AMP them, they WILL kick and play down to 80Hz easily and lower with good solid installation. Components dont do bass, they do midbass. I'd forget your plans and upgrade front comps, no point forking on JL baby subs in rear with such a weak front end.
Maybe you need to switch to a 10" sub if you want kicking bass? If you want midbass you need to focus on SETUP, midbass is where the subs and comps blend together, you must be getting cancellation if you are not hearing much midbass which means either your crossover is wrong or your phasing somewhere.
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AdiSRI
Member
Registered: 1st May 02
Location: Berkshire
User status: Offline
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Phasing??
And how do i go about trying to fix this cancellation?? The sub doesnt do any frequencies that the comps/6x9's do.
The sub amp lets me adjust phase and adjust time correction, but will any of this make any difference.
Also the sub is mounted flat rather than horizontal if this makes any difference?
The comps are rated at 50w RMS and the amp gives out 80w x 4 RMS so they are getting a bit over wat they need.
I will lower the gain on the 6x9's and put the comps filter back to 80Hz and see how it is.
Only advantage to the JL subs is low cost and the fact that they are perfectly rated to the amp i have.
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TOMAS
Member
Registered: 7th Aug 02
Location: Nottinghamshire
User status: Offline
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Phasing is where sound waves are formed and cancel one another out - basically its where the sub will move outwards and the comps will move inwards at exactly the same time thus no or little of that frequency will be played.
You'll find that your comps, 6x 9's and subs WILL be playing a lot of the same frequencies EVEN THOUGH your crossovers are set so that they shouldnt. Basically crossovers filter out sound at the point you set them at but they will allow some frequencies to still bleed through. You have to imagine it like a graph, You have a flat horizontal line which is the signal through the frequencies and your vertical would be volume (amplitude), you then set a cut off point, be it high pass or low pass, the line then begins to dip down at that point. The steepness that it cuts depends on how good your crossovers are - 6dB isnt steep at all and a LOT would bleed through, 24dB is pretty steep cutoff so hardly any frequencies past your cutoff point would bleed through.
Just mess around with the phase i.e switch pos and neg on the speaker terminals OR flick the switch on the amp if it has the ability and see how it sounds.
Theres a bit of a science to it and I know a bit but not LOADS i.e I havent studied the subject, just picked it all up over the years. Hope I have been some help mate and not sent your head spinning. Try the INFO section in ICE and Electrics
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Trotty
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Registered: 22nd Feb 01
Location: Bristol
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Some very good info in here, nice one TOMAS
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AdiSRI
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Registered: 1st May 02
Location: Berkshire
User status: Offline
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i have adjusted all the stuff as you said but it still sounds like its 2 bits, low bass and music seperate if you know what i mean...
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