Running 2 75W@ 8Ohms Subs

 

Bronze Member
Username: Aooo

Post Number: 29
Registered: Sep-05
Ok so the load would be a 4Ohm load in parallel.
How about the nominal power handling?
Would it be 150W@4Ohms?
Or will the ratings change since the 75W rating is rated @ 8Ohms?
Please Help
Cheers
 

Silver Member
Username: Rovin

Trinidad & T...

Post Number: 922
Registered: Jul-05
"Would it be 150W@4Ohms?" - thats right
 

Bronze Member
Username: Aooo

Post Number: 30
Registered: Sep-05
Thanks Rovin
Do you have any input as to which would be the better Sub for SQ:
JL Audio or MB Quart?
Both from last years entry level models.
 

Bronze Member
Username: Aooo

Post Number: 31
Registered: Sep-05
"Do you have any input as to which would be the better Sub for SQ:
JL Audio or MB Quart?
Both from last years entry level models."
... A bit more info
The JL is 8Ohms model so I would be going for 2 8" drivers in parallel.
The MBQuart would be a single 10" driver
Thanks :-)
 

Silver Member
Username: Rovin

Trinidad & T...

Post Number: 930
Registered: Jul-05
Just have to ask but is that your real name of Indian origin or its a word play thing like "girl/gal - shove it" ....lol no offence .

MB is more famous for its components products & JL for its reportedly out of this world subs . Alot of ppl diss them ONLY cause its expensive but the day i'm ready to buy something a little pricey i'd gladly buy a pair of 12w7 ...
 

Silver Member
Username: Rovin

Trinidad & T...

Post Number: 931
Registered: Jul-05
had some other tabs open so i'm now seeing u posting above - will get back to u in a while .
 

Bronze Member
Username: Aooo

Post Number: 33
Registered: Sep-05
:-) Yes its my real name. It's an Israeli name. Actually I lived abroad for quite a few years as a kid and it was always a bit of a problem for me. lol
So the better SQ?... MB or JL (Both from last years entry level models) I'll be getting a Sub and a Component set.
 

Silver Member
Username: Rovin

Trinidad & T...

Post Number: 933
Registered: Jul-05
will take some time to search out those products - can u post a link to each ....

& what amp u already have or r planning to use ?
 

Bronze Member
Username: Aooo

Post Number: 34
Registered: Sep-05
Thnk you very much Rovin
I have lins but some are PDF (sorry)
My Amp(pdf):
http://manuals.harman.com/JBL/CAR/Owner%27s%20Manual/CS%20Amp%20OM%20(rev%203-25-04).pdf
The MBQuart(No info on their web site):
http://www.epinions.com/pr-Mb_Quart_DWC_254/display_~full_specs
JL Audio (pdf):
http://mobile.jlaudio.com/pdfs/8-12IB4_BDS.pdf
 

Bronze Member
Username: Aooo

Post Number: 35
Registered: Sep-05
And thanks again :-) for all the help
 

Silver Member
Username: Rovin

Trinidad & T...

Post Number: 935
Registered: Jul-05
well that amp link isn't opening - just post the model no & i'll google it
here's a review of your MB sub http://www.carreview.com/Subwoofers/MB+Quart/PRD_52730_1808crx.aspx

JL -@ the bottom it says suited for infinite baffle systems & midbass systems
which 1 of these r u planning out & what r yor goals ? http://www.the12volt.com/caraudio/boxes1.asp
u already have bought an amp ?
 

Bronze Member
Username: Aooo

Post Number: 36
Registered: Sep-05
Thanks Rovin
Yes I already bought the amp.
Regarding the JL I will be getting 2 8", sorry for being dumb but what is "infinite baffle systems"?
I actually read this review but it doesn't give much info.+ I understand it's a dual voice coil.
My amp in a JBL CS50 but its new and I can actually trade it for a new Soundstream EGA4160.
The link for my amp works just the last part of it wasn't marked as part of the link.
http://manuals.harman.com/JBL/CAR/Owner%27s%20Manual/CS%20Amp%20OM%20(rev%203-25-04).pdf
Sorry you'll have to copy&paste the whole link
Many questions I know :-)
My only goal is to get the best SQ I can within the limited choice I have here, just for your knowledge over here these subs are around 220$.
The amp cost me the same.
I'm not Into SPL and very loud listening (a little loud :-)) but deeply into enjoying good SQ.
 

Bronze Member
Username: Aooo

Post Number: 37
Registered: Sep-05
--just an adition to the above--
....The JL's are around 300$ for the pair
 

Silver Member
Username: Rovin

Trinidad & T...

Post Number: 939
Registered: Jul-05
U see u r still not fully explaining your system plans so i'm trying to intelligently guess what u r doing .

If u read that link u will figure out IBS means that the sub is mounted in 'free-air' meaning not in a regular box enclosure . Its complicated to discuss .
? is - will 2 8" subs be put in an enclosure or will they be mounted in your car's rear dash panel ??????
Why did u buy a 4chan amp ? - will it also be used to power the subs ALONE or for 2 door speakers & 2 subs ??????
According to these 2 links the SS amp is rated with a higher rms ,however JBL is said to b the better brand ...
http://www.cardomain.com/item/JBLCS504
http://shop.store.yahoo.com/csexpo/egsost4chcar1.html

"not Into SPL" - then a sealed box is what u need for SQ bass .....
 

Bronze Member
Username: Aooo

Post Number: 38
Registered: Sep-05
Yes I am planning to run 2 component speakers in the front and a sub (maybe 2 in this case) in the trunk, ported or sealed box..
I will hook the whole system to my amp (think I'm sticking with the jbl)
Will the 2 JL subs be the better choice for SQ or the MBQuart?
I understand that generally a sealed box is the way to go?
Can you please check this out:
http://www.jbl.com/car/products/product_detail.aspx?prod=CS1000B/230&CheckProduc t=Y
It's a JBL 10" (cheaper) and it comes with an original sealed box.. but response is only starts at 38Hz, would this be suitable enough for SQ?
 

Silver Member
Username: Rovin

Trinidad & T...

Post Number: 951
Registered: Jul-05
That box looks pretty good & seeing that its fac made is reassuring . Note your amp does 67wrms & that is rated 100wrms so don't expect to be banging out real hard .
Is it possible that a higher rms JBL amp is available in your area like a 4ohms 100wrms x 4 channel ?
U can get some Infinity 6.5" comp for your doors .

38hz is no real worries cause IMO i like between 40 - 50hz . Sealed gives a more 'truer/tighter' bass & not too bangy like ported & bandpass . + u don't need to bother about tuning ports etc .
 

Bronze Member
Username: Aooo

Post Number: 40
Registered: Sep-05
Robin you are great
My amp is 67x4 but 2 channels would be bridged to get 162wrms @ 4Ohms for the sub so I guess that will be ok for the jbl? isn't it even too much power?
So you actually recommend that jbl sub for my listening preferences, can I expect decent sq from that sub?? won't either the 2JLs or the MBquart be better?(I have a guy that can tune a box for me with a computer program).... the other 2 channels will be powering a set of comps as you suggested.. any input on JBLGTO 6.5" components? again.. I like a smooth delicate tweeter (not to loud and "shouting") & good warm mids.
Sorry I keep coming with alternatives but one last choice I have for the sub is the Infinity 10" reference series, how would you compare its sq to the jbl & the other 2? Can I expect the jbl to have the same sq as the infinity?
 

Bronze Member
Username: Aooo

Post Number: 41
Registered: Sep-05
---adition to the above---
Won't I be missing out on stuff below the 38Hz? Is there actual sound at those freq or is it mainly to achieve SPL or just extensions to the overall bass? What would I be missing at those freq?
Again many questions I know :-)
But you are doing the work of an angel here, don't know how to thank you
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1779
Registered: Aug-05
there is sound at 20hz. but we can't hear that low, thus we just feel it.
if you want a SQ setup, then you need a sub that goes LOOOOOOOOOW.:-) so as not to cutout any frequencies that are recorded in the song.
your sub will be fine. it will play any frequency, but i believe any frequency above or below the stated, are reduced in output dramatically while being reproduced by that sub.

again, GW said that you can greatly manipulate a sub just by its enclosure.
 

Silver Member
Username: Rovin

Trinidad & T...

Post Number: 959
Registered: Jul-05
Well thanx - i don't do it for a living , i just have a knack to see things in a different light & offer my 2 cents based on some self experience & reading a ton of install info ,product manuals & reviews on the net .

U said that JBL sub/box is available to u so i'm thinking if thats 1 option u r now considering - well sure cause it'll save u trouble of building . I did not say 2 4get the MB ,that Jl i'm not sold on cause on the infite baffle stuff .

now i'm looking @ info showed here http://www.cardomain.com/item/JBLCS504 says
# RMS Power @ 4 Ohms: 67W x 4
# THD at 4-Ohm RMS Power: <1 %
# Bridged RMS Power @ 4 Ohms: 143W x 2

now logic says if u intend to bridge that amp then 4 chans will now = 2 chans - so how do u intend to run comps now ? ... u understand that right ?

Like i asked above
"Is it possible that a higher rms JBL amp is available in your area like a 4ohms 100wrms x 4 channel ?" - now this'll solve your problem of too little or too much power .

JBL r more famous for their amps & subs so i'd pick Infinity 6.5" (3 models i think) over jbl like what i'm getting 4 my own system .
 

Silver Member
Username: Rovin

Trinidad & T...

Post Number: 960
Registered: Jul-05
Oh BTW - whilst i was thinking/typing thats my forum buddy "MUDDY" - lol

He's very good too & u can talk about this stuff with him too ....Upload

MUDDY -
TAKE SOME TIME & READ THIS ENTIRE THREAD ,CHECK OUT THE STUFF MENTIONED & LET ME KNOW IF WE ARE GOING DOWN A GOOD PATH ....
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1782
Registered: Aug-05
u can run a 2channel amp on 4 speakers.(4channel bridged to 2 channels)
you simply use one bridged channel to amplify the FL and RL speakers, and the other bridged channel to run the FR and RR speakers.:-)
you just wont have stereo sound coming out of the front set, and stereo sound coming out of the back speakers. your left stereo channel will be the front and rear left speakers, and vice versa for the right channel.

does that make sense to ya?
 

Bronze Member
Username: Aooo

Post Number: 43
Registered: Sep-05
You can use it for a 3 way setup 2 channels bridged and the other 2 unbridged. (143Wx1 & 67Wx2)
The thing is that I wanted the newer jbl GTO 4x100 but it is completely out of stock locally (it was selling like crazy) and they won't get any new ones soon.
But since my amp can be set up 3 ways I guess its ok?
Something is bothering me regarding the 38Hz... This is not the first time someone told me that for good sq I need a sub that goes all the way down???
I also found just now online a store selling Cadence Q & Flash series subs, any opinions regarding the sq of these?(I have a new post for this)
 

Silver Member
Username: Rovin

Trinidad & T...

Post Number: 962
Registered: Jul-05
Gal - in case u need an idea of brands then http://pub14.ezboard.com/fcaraudiotalkfrm27.showMessage?topicID=27.topic

there's an updated list on that forum but u have 2 reg there 2 see it .
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1783
Registered: Aug-05
sorry, i didn't read the whole thread(until now)
if it was me, i would get the 2 JBL's, and then get some infinity comps.
your setup will be just like mine.
i have a 4 channel amp, 2 channel run the mids and highs, and 2 are bridged to the sub.:-)
if the JBL's are rated at 75w a piece, then i would get those, b/c your amp will power them nicely.
 

Silver Member
Username: Rovin

Trinidad & T...

Post Number: 963
Registered: Jul-05
U can also get a 2 chan like Muddy said , but Muddy , Gal says he want a SQ system - so that must be taken into account too .

"You can use it for a 3 way setup 2 channels bridged and the other 2 unbridged. (143Wx1 & 67Wx2) " - sounds logical too but will there still be stereo sound off the 2 front comps ?

i've never had the cause to do that - have u Muddy ?
 

Silver Member
Username: Rovin

Trinidad & T...

Post Number: 964
Registered: Jul-05
oh - i'm a slow typer , u responded whilst i was typing - lol
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1785
Registered: Aug-05
no, but if i were to upgrade my components for example. i only have 75w going to each speaker.

if i got rid of my rear speakers, and bridged my 4 channels to 2, then ran one channel to the FL, and one channel to the FR(for say some DLS Iridium 6.2's. 100wRMS) then each side would get 180w from my amp, b/c of the bridged channels.
 

Bronze Member
Username: Aooo

Post Number: 44
Registered: Sep-05
Thanks... But the 2 subs are 8" JL audio not the jbl
The jbl would be a single 10" sub... you mentioned that the freq response is not so good for achieving good sq?
And the JLs are oft the topic because as far as I understood from Rovin they are more used for midbass setups & infinite baffle.
If it wont bother you too much and you have the time I will be glad if u can check out the links as well.
Thanks to both you guys.
 

Silver Member
Username: Rovin

Trinidad & T...

Post Number: 965
Registered: Jul-05
Well both of us i'm sure are thinking that u get the 2 JBL sub/box & thats what we working with so i think thats pretty much settled .

Thing is Gal - if u lived in either US or Canada in less than 5 posts i'd show u a complete setup with the best prices to buy but since your equip choices r so limited its taking longer ...
 

Bronze Member
Username: Aooo

Post Number: 45
Registered: Sep-05
I know man :-)
You are a bit confused I can only get 1 JBL sub/box in my budget.
The 2 subs only applied to the JLAudio subs which you said wont be to good.
(Just a reminder I drive a VW Golf)
One thing bothers me... Muddy wrote" if you want a SQ setup, then you need a sub that goes LOOOOOOOOOW", is that the exact case?
 

Bronze Member
Username: Aooo

Post Number: 46
Registered: Sep-05
--another addition to the above questions--
Please just bare with me a bit longer :-)
Btw... The list says jbl are only good for amps
 

Silver Member
Username: Rovin

Trinidad & T...

Post Number: 967
Registered: Jul-05
OK - well even with that 1 JBL sub/box - it'll work just fine .
Well i won't let that personally bother me but u know i admire JBL 4 being honest that their sub does 38hz - alot of companies like 2 exaggerate & say their sub does 20hz-500hz .

38hz is pretty reasonable for a 10" sub . Like i said b4 i like it a bit higher cause recently i did a box for my bro that was tuned @ 45hz & we both didn't like how it sounded so we retuned it to 50hz & 2 us the overall sound was more reasonating & pleasing 2 our ears .
So don't lose sleep over a few Hzs - organise your stuff & post some pics/feedback when u get it all done ......
 

Gold Member
Username: Basshead86

Ocala, FL USA

Post Number: 1789
Registered: Aug-05
that sub/box combo will do exactly what you want it to.


it seems strange to me that that has a frequency response of 38-500.

most everyone i know or have read about cut their subs off at 80hz or below, so 500hz is pointless.
every speaker has rolloff, which means that as the sound fades out of the speaker, it will produce lower frequencies as the cone stops its movement.(i think, it's getting late. lol)
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