[Suvrajit]

Hi Gurus,
I recently bought a swift VXI and with the limited knowledged that i have(have never really driven before, straight from the driving school to the wheel!). And with this vast knowledge went on with my ICE setup(BTW I picked up the Term ICE here ) I bought JBL 607C for front and GTO 937 rear with Pio 6950IB, have been a fan of JBL after seeing (not listening) them a lot onstage for concerts. I am pretty satisfied(read my ears) given the fact the kind of expectations that I have- i am sure that expectations gotta do a lot with your knowledge of what to expect. But after reading almost all the threads(yes I mean it!!) i am completely , I bought the stuff with bill and store warranty from a store called Supercarz(any one knows them) actually a lot many stores in JC road has all these fancy neon signs with JBl,pio Sony on them( i thought that if you are declaring in public then you should be legal reatailers, or so I thought) i chose supercarz cuz they were giving me a great deal( again my idea of great!!) @ 607c at 5k, 937 at 3.5 and HU @7.3k and paid 12.5 vat on the total amount and spent around 18500 in all. After enlighting myself in the forum i realised that my bill has no SL nos mentioned in them, though I have been given box pack speakers i actually have the boxes at home, not for the HU though, now i am worried that the stuff can be spurious, Is there any wasy that i can identify the genuinity of the products, JBL- Sam, pls, puhleez help!!! And also the set up is some thing that I am worried about. the front comps are fitted in the stock location in the doors and the tweeters mounted high on the A pillars facing some what to wards the driver and passenger and the 937's mounted on MDF plank. The cross overs were safely tucked away some where under the golve box and I was pretty satisfied with the set up initially(excitement did it all I guess) however post the 1st service which was done last friday I found one cross over dangling by the connecting wires only to realise that they were taped in to whatever(nice install!!!) is there any where that i can get these installed pproperly and also planning to put a JBL 75.4 amp and a sub( thank heavens I did not do all at a time), Pls suggest where can i buy them from with b&w and have them installed. I read about Anwar a lot in the forum- can anyone give me his contact details or suggest some one better and a source of procuring these comps- Pls also suggest what other options should i be looking at, I am not looking at a show off machine but just clean and pure music, I listen to everything from classic rock to alternative to RD Burman. Will really appreaciate any help in this front. Mods pls allow this thread and better pls advice. i am an absoleute novice with an open mind, Apologies for the long thread

Thanks

[Sam Kapasi]

Goodness, that was a while to read.

Hello Suvrajit
Welcome to Team-BHP. Welcome to the rather eccentric ICE section. Please do read the rules in the announcement section.

Here's a friendly bit of advice. TO make you posts more readable, use more punctuations and breaks. End your point by ending the sentence/para and beginning a new one on the next line.

Like this. Makes it easier on the reader.

Now I know SUpercarz and I know that you have genuine JBL products there. So relax. Your prices are pretty good too. I suspect the Pioneer 6950 is purchased in grey, so maybe you got no box. This is not so bad either.

As far as the mounting of your speakers, they seem to all be in the right places, perhaps you can take it back to the installer and ask him to tie up, or screw mount the crossovers somewhere. With your supervision, they might just do it well.

The 75.4 is a well respected amplifier. It will drive most powerful subwoofers easily, with 2 channels. The other 2 channels can be used on HPF to drive those 607C's in the front.

Enjoy your music amigo

[Suvrajit]

Thanks so Much Sam And I will keep your advise in mind while posting.

I have some more queries now, if you will be kind enough to throw some light on that? decided on 75.4 for amp however a little confused with the sub-

1) whats the difference between GTO1204BR and CS1204B? and the prices please
2) Whats the difference between a sealed box and a bass reflex box?

I dont want boom but want a tight bass.

Can you pls suggest a sub accordingly and also the pricing ?

Thanks

[Sam Kapasi]

Originally Posted by Suvrajit

1) whats the difference between GTO1204BR and CS1204B? and the prices please
2) Whats the difference between a sealed box and a bass reflex box?

As you've probably figured out, the CS1204B is a sealed box, while the GTO1204BR is a bass relex box.
The woofer used in the BR is superior and more powerful.

It is a debatable answer. The common easy answer is that sealed boxes are tighter and more precise. But they are less sensitive.
A well designed bass reflex box can be accurate too, and loud than a sealed box.
They both have different sounds. However they are not the same products in different boxes. The BR is a superior and more expensive product.

I suspect LBM will be here shortly. He has recently switched from sealed boxes to BR boxes.

[Suvrajit]

Thanks Sam

Is a bass reflex box the same as in a ported box?

[low_bass_makker]

Originally Posted by Suvrajit

Thanks Sam

Is a bass reflex box the same as in a ported box?

yes exactly. and I love the ported box..the extra output it gives is awesome.

[vijay_k]

Can i connect GTO1202D or a GTO1204D sub to a GTO75.4 amp?
I am asking this question because i have lost the manual of the Amp and i am totally confused.

My doubt is a GTO1202D has a 2 ohm voice coil and a GTO1204D has a 4 ohm voice coil so the total resistance for GTO1202D would be 1 or 4ohms depending on type of connection (i.e. Series or parallel) and for GTO1204D the total resistance would be 2 or 8ohm again depending on the type of connection.

So is it possible to connect GTO1204D sub to GTO75.4 Amp? Because this amp only supports a 4ohm coil i guess and the sub can be wired only in a combination where the resistance would be 2 or 8ohm. I am a bit confused about this please help me.

And i am confused about which sub i should go for, my installer tells me that a sub with 2 ohms voice coil is better compared to the 4 ohms ones, is this true?

What would be the output (rms value) of GTO75.4 in bridged mode?

And can somebody please tell me the cost of GTO1202D and GTO1204D subs.

Thanks in advance,
Vijay

[Suvrajit]

Whats the difference between a DVC sub and a SVC sub... apart from the wiring difference that I could figure out from the net, is there any SQ difference that can be spoken about?

[low_bass_makker]

Originally Posted by Suvrajit

Whats the difference between a DVC sub and a SVC sub... apart from the wiring difference that I could figure out from the net, is there any SQ difference that can be spoken about?

in a SVC there is a single voice coil and in a DVC there is two coils not physical two but one wounded over the other or wounded simultaneously.


there is no differnce in SQ but in wiring them you can get some flexibility.like you can wire two 4 ohms dvc sub to get final 4 ohms.

[low_bass_makker]

Originally Posted by vijay_k

Can i connect GTO1202D or a GTO1204D sub to a GTO75.4 amp?
I am asking this question because i have lost the manual of the Amp and i am totally confused.

My doubt is a GTO1202D has a 2 ohm voice coil and a GTO1204D has a 4 ohm voice coil so the total resistance for GTO1202D would be 1 or 4ohms depending on type of connection (i.e. Series or parallel) and for GTO1204D the total resistance would be 2 or 8ohm again depending on the type of connection.

So is it possible to connect GTO1204D sub to GTO75.4 Amp? Because this amp only supports a 4ohm coil i guess and the sub can be wired only in a combination where the resistance would be 2 or 8ohm. I am a bit confused about this please help me.

And i am confused about which sub i should go for, my installer tells me that a sub with 2 ohms voice coil is better compared to the 4 ohms ones, is this true?

What would be the output (rms value) of GTO75.4 in bridged mode?

And can somebody please tell me the cost of GTO1202D and GTO1204D subs.

Thanks in advance,
Vijay

JBL Car & Marine Audio

I think 75.4 is not 2 ohms stable...that Sam Bhai will tell in a movement.

[DerAlte]

Originally Posted by Suvrajit

Whats the difference between a DVC sub and a SVC sub... apart from the wiring difference that I could figure out from the net, is there any SQ difference that can be spoken about?

The difference is in the flexibility it gives for matching impedance with the amplifier. SVC, with a single coil, has a fixed impedance; so if you have bought 4ohm SVC, you need an amp that pushes sufficient power through 4ohms.

With a DVC of let's say 2 coils of 2 ohms each, you can wire it for 1ohm (parallel) if your amp can push that, or 4ohms if that is suitable for the amp.

With a DVC you can also use a 2 channel amp, with each channel driving 1 voice coil. This is an advantage in case you have an amp that cannot be bridged. If the amp can be bridged, both the coils can be combined and driven like 1 over the bridge.

SQ will not be affected, SPL would - depending on what amp one is using.

LBM-bhai, theek bola na maine?

[Sam Kapasi]

Originally Posted by vijay_k

Can i connect GTO1202D or a GTO1204D sub to a GTO75.4 amp?
I am asking this question because i have lost the manual of the Amp and i am totally confused.

My doubt is a GTO1202D has a 2 ohm voice coil and a GTO1204D has a 4 ohm voice coil so the total resistance for GTO1202D would be 1 or 4ohms depending on type of connection (i.e. Series or parallel) and for GTO1204D the total resistance would be 2 or 8ohm again depending on the type of connection.

So is it possible to connect GTO1204D sub to GTO75.4 Amp? Because this amp only supports a 4ohm coil i guess and the sub can be wired only in a combination where the resistance would be 2 or 8ohm. I am a bit confused about this please help me.

And i am confused about which sub i should go for, my installer tells me that a sub with 2 ohms voice coil is better compared to the 4 ohms ones, is this true?

What would be the output (rms value) of GTO75.4 in bridged mode?

And can somebody please tell me the cost of GTO1202D and GTO1204D subs.

Thanks in advance,
Vijay

The GTO1202D and 1204D are identical in all respects, except for the impedance of their voice coils. This makes the 1202D louder, given the same conditions, simply because it is lower in imepdance.
The 75.4 amplifier is perfectly stable at 2 ohms, unbridged. In bridged mode, the effective impedance "seen" by each channel would be 1 ohm. Not such a good idea.

Now for the tricky question. You have a 1202D and a 1204D and you want to connect it to the 75.4.

I can suggest this

• Make the 1202D 4 ohms. Connect it on one channel in bridged mode. Make the 1204D 8 ohms, connect it to the other channel bridged.
  
  The channel on which you've connected the 1204D should have an increased gain, as the impedance load presented to it is twice as much. Increase it till it sounds as loud as the other woofer.

I also contemplated the option of creating two 6 ohms loads (by placng in series, one coil of the 1204D with one coil of the 1202D. While this will present an equal load to the amplifier on both bridged channels, one woofer will be louder than the other. And you wont be able to control it.
So the above option is the best way.

[low_bass_makker]

Originally Posted by DerAlte

The difference is in the flexibility it gives for matching impedance with the amplifier. SVC, with a single coil, has a fixed impedance; so if you have boug....................bridged. If the amp can be bridged, both the coils can be combined and driven like 1 over the bridge.

SQ will not be affected, SPL would - depending on what amp one is using.

LBM-bhai, theek bola na maine?

ek dum correct hai gaa.

Normal the mono amps in the market are 2 ohms stable. yes there are 1 ohms stable also but the major are 2 ohms one. and for the 4 or 2 channel amp in the bridged mode the amp is 4 ohms stable.

so if one has a mono amp and want to run a single sub get the 4 ohms dvc wire it parallel

so if one has a mono amp and want to run two subs get the 2 ohms dvc wire them series and both the subs parallel to get final 2 ohms


so if one has a 4 or 2 channel amp and want to run a single sub get the 2 ohms dvc and wire it series and if one has to run two subs the bridged the other channel and wire the second sub there.

[low_bass_makker]

Originally Posted by Sam Kapasi

The GTO1202D and 1204D are identical in all respects, except for the impedance of their voice coils. This makes the 1202D louder, given the same conditions, simply because it is lower in imepdance.
The 75.4 amplifier is perfectly stable at 2 ohms, unbridged. In bridged mode, the effective impedance "seen" by each channel would be 1 ohm. Not such a good idea.

Now for the tricky question. You have a 1202D and a 1204D and you want to connect it to the 75.4.

I can suggest this

• Make the 1202D 4 ohms. Connect it on one channel in bridged mode. Make the 1204D 8 ohms, connect it to the other channel bridged.
  
  The channel on which you've connected the 1204D should have an increased gain, as the impedance load presented to it is twice as much. Increase it till it sounds as loud as the other woofer.

I also contemplated the option of creating two 6 ohms loads (by placng in series, one coil of the 1204D with one coil of the 1202D. While this will present an equal load to the amplifier on both bridged channels, one woofer will be louder than the other. And you wont be able to control it.
So the above option is the best way.

Sam Bhai why confuse the chap.

get the two 1202d 2ohms dvc wire them in series and put each of them on bridged channel of the 75.4 and bolo tara rara.

[DerAlte]

Originally Posted by low_bass_makker

Sam Bhai why confuse the chap.

get the two 1202d 2ohms dvc wire them in series and put each of them on bridged channel of the 75.4 and bolo tara rara.

Hallo Gurujis, from what @vijay_k has written, I think his doubt centers around whether he should purchase 1202D OR 1204D, not 1202D AND 1204D. He only wanted "the cost of GTO1202D and GTO1204D subs"!

@vijay_k: Though the JBL GTO75.4 II manual does not say "bridged mode" explicitly, "284 watts RMS x 2 channel at 4 ohms, 14.4V supply and ≤1% THD + N" as mentioned will mean 284W RMS in the bridged mode. This would assume that each channel in the bridged mode (each half of the bridge, to put it in a different way) should see 2ohms.

The amp manual is available on-line http://manuals.harman.com/JBL/CAR/Ow...v_12_14_04.pdf