[hrsraghav]

GTA4 MKII gives RMS power of 4 x 60 Watts
whereas the JBL 75.4 gives 4 X 104 Watts at 4 ohms
Does that means if we bridge two channels, then we will get 120 W RMS from GTA4 and 208W from JBL 75.4?
Couldn't find the details of Kenwood 8401
the GTA4 costs 6K with BW. and as metioned in above post the 75.4 costs 8.5K in grey.
Can we first point out which Amp in the range of 8K is best for a Sub?
Also I am not zeroing out on only these brands, plz do suggest if other good options are available in same range.
Also apart from power is the JBL also best in other features also(I am not aware of what all is required to look for in a Amp).
And then out of Subs which one is best for around 5-6K?

[adityamunshi]

JBL 75.4 is probably the only amp of its class @ 8K (grey). Its replacement the GTO1004 has an MRP of 14K

Other options are around 9-10K
GZ 4.120 - 75 x 4 WRMS
Panasonic CY-PA 4003- 64 x 4 WRMS
Blaupunkt GTA 480 75 x 4 WRMS

Originally Posted by hrsraghav

GTA4 MKII gives RMS power of 4 x 60 Watts
whereas the JBL 75.4 gives 4 X 104 Watts at 4 ohms
Does that means if we bridge two channels, then we will get 120 W RMS from GTA4 and 208W from JBL 75.4?
Couldn't find the details of Kenwood 8401
the GTA4 costs 6K with BW. and as metioned in above post the 75.4 costs 8.5K in grey.
Can we first point out which Amp in the range of 8K is best for a Sub?
Also I am not zeroing out on only these brands, plz do suggest if other good options are available in same range.
Also apart from power is the JBL also best in other features also(I am not aware of what all is required to look for in a Amp).
And then out of Subs which one is best for around 5-6K?

[amit_mechengg]

Originally Posted by hrsraghav

GTA4 MKII gives RMS power of 4 x 60 Watts
whereas the JBL 75.4 gives 4 X 104 Watts at 4 ohms
Does that means if we bridge two channels, then we will get 120 W RMS from GTA4 and 208W from JBL 75.4?
Couldn't find the details of Kenwood 8401
the GTA4 costs 6K with BW. and as metioned in above post the 75.4 costs 8.5K in grey.
Can we first point out which Amp in the range of 8K is best for a Sub?
Also I am not zeroing out on only these brands, plz do suggest if other good options are available in same range.
Also apart from power is the JBL also best in other features also(I am not aware of what all is required to look for in a Amp).
And then out of Subs which one is best for around 5-6K?

JBL 75.4 is an unbeatable amp with 284 watts RMS over a bridged mode.
i have tried many other amps which give around 120-180 watts rms over bridged mode. to be frank the sub cries for more watts.

and my warning is stay away from sony amps. i dont call them amps at all.

[shuvc]

Originally Posted by hrsraghav

GTA4 MKII gives RMS power of 4 x 60 Watts
whereas the JBL 75.4 gives 4 X 104 Watts at 4 ohms
Does that means if we bridge two channels, then we will get 120 W RMS from GTA4 and 208W from JBL 75.4?

75.4 is 284rms bridged @4ohms

I think to get an approx idea of the bridged power at 4ohms, you could multiply the rms power in the 'un-bridged' 4ohm mode by around 2.75 to 3

So GTA4 MKII = 60*2.75 ~ 160wrms to 60*3 ~ 180wrms @ 4ohms

[Magma]

@nishantji,vb

The GT5 can run with a bridged input of 60*2rms. However it sounds better when fed with more power.(Though not much diff if you Maybe jack up the gains of the 60*2rms to 3/4th and a bit more)
The CS1204 ( i.e the GT4 12" sub from JBL is slightly less power hungry than the GT5)
It may be interesting to see how that functions

Now the GZ sub definetely needs more power than the JBL's.
I wouldnt advice the 60*2rms bridge on this one.

The Kenwood 8401/4 and JBL GT5 are very good subs. The only reason i said to use them as a last resort (read TIGHT budget) is because they supply only approx 150 rms in bridged mode ( i dont belive that 180rms bit-if that were true what use of the GT53001 that gives only 175rms)

the 75.4 as you guys say can be had at 8500rs and I say that 2 kenwood 2channel amps(one 60*2 and the other 75*2rms,if you can find it) can be had in that same value(maybe 1K more MAX) not 2-3 K more

Nishantji,Adityaji
I am doing a bit of auditioning with subs at boom this week.Maybe you should join in if you've got the time

Also consider driving a 10inch sub with the 60*2 rms bridge.
I believe the 10incher will be happy. Another advantage is a smaller box so less boot space.

Also note: if you plan to use the sub in free air then 60*2rms bridge should be sufficient(though i think both you guys are "Sealed!"

[adityamunshi]

I wish i could've been there but no plans of coming to mumbai anytime soon. But do post your experiences in detail. Looking forward to that.

Originally Posted by Magma;861782
Nishantji,Adityaji
[B

I am doing a bit of auditioning with subs at boom this week.Maybe you should join in if you've got the time[/b]

[Magma]

i forgot to add
the blaupunkt 4 channel in question is also a very good amp but since it supplies 60*4 rms the same as the Kenwood i dont see why you should pay approx 1800rs extra unless ofcourse you like the signature sound

Also 2 nos 2 channel amps would only require a 16 mm sq cable instead of 10mm sq for a single 4 channel (according to the specs we are discussing) This would add to rs 400extra. plus the cost of a distribution box, Sp maybe yes 2 ams would need more cost in wiring but just power wire and that too i think 700-800rs

[nishantgandhi]

Originally Posted by hrsraghav

Can we first point out which Amp in the range of 8K is best for a Sub?
And then out of Subs which one is best for around 5-6K?

This would be helpful information from some wise men. I had listed down some names which I have gathered through TBHP. However, I was not aware of the intricacies regarding power supply nuances for those subs.

Last I remember, either B&T or Navin had said that Blaupunkt GT4, Kenwood 840x and JBL GT5 are more or less the same. So the decision would be based on their price in that case, or signature sound (if possible to distinguish!)

Originally Posted by shuvc

75.4 is 284rms bridged @4ohms

I think to get an approx idea of the bridged power at 4ohms, you could multiply the rms power in the 'un-bridged' 4ohm mode by around 2.75 to 3

So GTA4 MKII = 60*2.75 ~ 160wrms to 60*3 ~ 180wrms @ 4ohms

So to put in it another way, which sealed subwoofer would run happily off that kind of power? EDIT: Also, does a sealed sub require more power than ported/BR/IB/free air?

Originally Posted by Magma

Nishantji,Adityaji
I am doing a bit of auditioning with subs at boom this week.Maybe you should join in if you've got the time

Date? Time? Would try to join you

Originally Posted by Magma

Also consider driving a 10inch sub with the 60*2 rms bridge.
I believe the 10incher will be happy. Another advantage is a smaller box so less boot space.

I was considering that as well. I am anyways looking at the sub to complement my front sound stage, and not to over power them. Hence, I thought a 10 inch sub would be less 'dominating' than a 12 inch one.

Originally Posted by Magma

Also note: if you plan to use the sub in free air then 60*2rms bridge should be sufficient(though i think both you guys are "Sealed!"

I have not actually heard free air installs, hence cannot comment on the bass. What I heard were ported, sealed and BR subs and I liked sealed the most.

EDIT: AFAIK, free air sub can be installed on an MDF tray, or in spare wheel well only? Both would sacrifice boot space right? Any other feasible locations?

Originally Posted by Magma

i forgot to add
the blaupunkt 4 channel in question is also a very good amp but since it supplies 60*4 rms the same as the Kenwood i dont see why you should pay approx 1800rs extra unless ofcourse you like the signature sound

But if Blaupunkt also supplies 60wx2 RMS (same as JBL or Kenwood), then why is it rated better by many on the forum? Wouldn't it also be less than adequate power for the subwoofer?

As is the tradition with ICE on TBHP, I was almost final on the setup. But then out of curiosity, I post a query to confirm, and the confusion starts again. If this continues, I dont know when I will ever get to install ICE in my car. It has already been 4 months of research!

[greenhorn]

I'll join in the party as well
Even I've got a few sub doubts floating around in my head. I'd like a sub with SQ, but a brawny monobloc isnt my idea. I just want *some* LF when listening to music at background levels. the boom from my rear 6x9's doesnt cut it. Its just the sheer wattage of these amps that overwhelms me. I listen to my ICE a lot, even with the engine off, so a power hungry sub will surely kill my battery ( maybe a seperate on/off switch) for the amp will help, But my question is, Beside the sheer amount of power , What tangible benefits does a monobloc amp give as opposed to a bridged 2 channel amp of approximately the same power output, or alternately, a lower power 2 ch amp when both are run at the same levels?
I listened to redfire's 2 ch blau amp driving a sealer blau sub, and it was more than adequate, how would a monoblock improve on that ?

[Magma]

Originally Posted by nishantgandhi

This would be helpful information from some wise men. I had listed down some names which I have gathered through TBHP. However, I was not aware of the intricacies regarding power supply nuances for those subs.

simple JBL75.4 for 8500rs
GZ MK2 sub for 5500 rs ( of course you have to pay for he box seperately)

if that goes over budget then consider JBL GT5 sub (grey approx 3-3.5K)

Last I remember, either B&T or Navin had said that Blaupunkt GT4, Kenwood 840x and JBL GT5 are more or less the same. So the decision would be based on their price in that case, or signature sound (if possible to distinguish!)

correct

So to put in it another way, which sealed subwoofer would run happily off that kind of power? EDIT: Also, does a sealed sub require more power than ported/BR/IB/free air?

yes a sealed sub requires more power than free air, i would assume 60*2rms bridge would be fine for free air but a selaed one would be happier with 200rms total

Date? Time? Would try to join you
PLease PM me your number


I was considering that as well. I am anyways looking at the sub to complement my front sound stage, and not to over power them. Hence, I thought a 10 inch sub would be less 'dominating' than a 12 inch one.

EDIT: AFAIK, free air sub can be installed on an MDF tray, or in spare wheel well only? Both would sacrifice boot space right? Any other feasible locations?

How would a spare wheel sub take up boot space. Instead it would take NO boot space! the sub fits entirely in the inverted spare wheel.
This is what im goin to audition in BOOM

But if Blaupunkt also supplies 60wx2 RMS (same as JBL or Kenwood), then why is it rated better by many on the forum? Wouldn't it also be less than adequate power for the subwoofer?

Depends on how much power you want to feed your sub,or how loud you want to play your sub

As is the tradition with ICE on TBHP, I was almost final on the setup. But then out of curiosity, I post a query to confirm, and the confusion starts again. If this continues, I dont know when I will ever get to install ICE in my car. It has already been 4 months of research!

Dude stop getting so hasseled.Dont know if you are a real audiophile or just a regular listener.
If youre looking for budget subs jst get a Kenwood,JBL or Blau. it doesnt matter. at least i couldnt make out the difference(im a noob in audio)

As for subwoofers The JBL GT5,And Blaupunkt 12 incher(only 3750rs with bill at Avantibai gokhle road) are nice budget subs.The GZ is a little more expensive but some reviews here(mine pending at boom) seem to suggest it has a very dfferent signature sound.
Stay away from pioneer shallow subs though if you're running 6*9's ( i auditioned them, they give the same bass as the 6*9's so there you go)

See so simple!

[DerAlte]

The issue is not so simple that we can make a spreadsheet / table of subs & amps, run a finger down the sub model column and trace along a row to know which amp is best suited.

How much power you need to pump (and hence have on call) depends on
1. Sensitivity of the sub
2. Car gain (car model dependent)
3. Type of enclosure (BR/IB produce louder sound than SB, so SB needs more power to reach the same dB level; but BR/IB are not as faithful to the signal unless well designed)
4. Sensitivity of your ears and your listening preference (especially, whether the bass is for you, or you desire publicity in your immediate vicinity by way of THUMP/BOOM). Navin prefers the level to be "just sufficient that you can detect its absence". Another person may want the neighborhood to notice his presence by the loudness of his bass - like "Hoshiyar, Maharaj ki sawaari aa rahi hai"!!! They would need 2 subs and 2 monos
5. Distance of sub from major listening point, as well as obstacles (is the sub in the boot well insulated from the cabin, or are you sitting above the under-seat sub). Closer = lesser power needed. Sitting on the sub = obviously the least power. In the boot of a sedan = definitely a monoblock amp needed. In the boot of a hatch, no obstructions = somewhere in between.

I have tried to give more inputs, not a ready-made thumbrule - maybe it helps you understand and dissect your problem.

[nishantgandhi]

Originally Posted by DerAlte

The issue is not so simple that we can make a spreadsheet / table of subs & amps, run a finger down the sub model column and trace along a row to know which amp is best suited.

Yes DerAlte, I understand that its not a matrix of combinations and one-size-fits-all approach probably doesn't work here.

3. Type of enclosure (BR/IB produce louder sound than SB, so SB needs more power to reach the same dB level; but BR/IB are not as faithful to the signal unless well designed)

Theoretically, if I don't want a highly over imposing bass, then 60x2 WRMS should be sufficient for a budget sub, right? It may not be pushing the sub to its limits and pounding out huge bass. But thats now the point anyways.

4. Sensitivity of your ears and your listening preference (especially, whether the bass is for you, or you desire publicity in your immediate vicinity by way of THUMP/BOOM). Navin prefers the level to be "just sufficient that you can detect its absence". Another person may want the neighborhood to notice his presence by the loudness of his bass - like "Hoshiyar, Maharaj ki sawaari aa rahi hai"!!! They would need 2 subs and 2 monos

The car is a hatch back (Getz) and my preference is same as Navin ("just sufficient that you can detect its absence"). As I have mentioned before in this thread, I am looking for the sub to complement my front components with the lows, and NOT play independent to overwhelm the front sound stage. I dont have rear 6x9s in the setup and dont plan to have them either.

5. Distance of sub from major listening point, as well as obstacles (is the sub in the boot well insulated from the cabin, or are you sitting above the under-seat sub). Closer = lesser power needed. Sitting on the sub = obviously the least power. In the boot of a sedan = definitely a monoblock amp needed. In the boot of a hatch, no obstructions = somewhere in between.

I intend to put the sub enclosure in the boot, as is the case with hatchbacks normally. I have not heard of spare wheel well installs and anyways, cannot do away with the spare wheel, so I guess that option is ruled out.

I have tried to give more inputs, not a ready-made thumbrule - maybe it helps you understand and dissect your problem.

Thanks for your inputs! Appreciate it!

[nishantgandhi]

Originally Posted by Magma

Dude stop getting so hasseled.Dont know if you are a real audiophile or just a regular listener.
If youre looking for budget subs jst get a Kenwood,JBL or Blau. it doesnt matter. at least i couldnt make out the difference(im a noob in audio)

As for subwoofers The JBL GT5,And Blaupunkt 12 incher(only 3750rs with bill at Avantibai gokhle road) are nice budget subs.The GZ is a little more expensive but some reviews here(mine pending at boom) seem to suggest it has a very dfferent signature sound.
Stay away from pioneer shallow subs though if you're running 6*9's ( i auditioned them, they give the same bass as the 6*9's so there you go)

See so simple!

Thanks for the suggestions. I dont know whether I can be called an audiophile, but I do have an taste and certainly can appreciate different genres of music and sounds.

Its not about getting hassled. I am just curious! So wanted to get ideas and suggestions, and get to learn in the process.

[low_bass_makker]

Originally Posted by Magma

Stay away from pioneer shallow subs though if you're running 6*9's ( i auditioned them, they give the same bass as the 6*9's so there you go)

Totally agree the pioneer shallow sub are of no use. I had one with me but it has nothing more than two ovals when compared to bass output.

[navin]

Originally Posted by greenhorn

I'll join in the party as well
Even I've got a few sub doubts floating around in my head. I'd like a sub with SQ, but a brawny monobloc isnt my idea... Its just the sheer wattage of these amps that overwhelms me. ..What tangible benefits does a monobloc amp give as opposed to a bridged 2 channel amp of approximately the same power output..I listened to redfire's 2 ch blau amp driving a sealer blau sub, and it was more than adequate, how would a monoblock improve on that ?

Fantastic question. To think I was just this morning lanmenting to a friend on why we dont get quality questions like this posted often enough on TBHP. My friend told me "Relax navin, TBHP is a car forum; go get your fix on diyudio/audioasylum/etc...". To that friend I say "Boooo we are not engine-vengine types only! Ha!"

To produce bass one needs to move air, lots of it. To move air one needs a large cone with suffcient mass. To move that large cone one needs electrical power in the form of watts. Class D amps give you this power in smaller packages. In most cases they are very adequate.

All things remaing equal lets consider 2 amps. Amp A is a 2 ch. amp that puts out 50W rms/4ohms, 100W/2ohms or 4 ohms when bridged, 200W at 1ohms or 2ohms when bidged. Amp B is a monoblokc that puts out 100W at 4ohms, 200W at 2ohms, and 400W at 1ohms. Now both these amps are great amps. Both will drive a sub well. The Monoblock might be a bit more stable at lower impedance and that means if the sub's impedance curve is complex (most siubwoofers have inductive impedance curves that can peak at resonance and fall fast mkaing them to be quite complex) the monoblock will have an edge.

Also when you bridge 2 channels on a stereo amp you also half it's damping factor and the higher the damping factor the better the control the amp has on the speaker.

Usually when an amp is not able to control the speaker properly the speaker will sound a bit woolly.

Also remember the example of the stereo amp I have given is of a very good stereo amp. Most plain jane stereo amps are not stable at 2 ohms when bridged. Now a speaker's impedance is not constant (if t were we'd call it resistance) but varies with frequency. So a speaker that is rated at 4homs nomial impedace can see it's impedance drop to 2ohms for a small frequency band. If there happens to be music in that small band the amplifer will loose control (albeit temporarily) and once cna hear this loss of control.

many years ago a company called Wilson Audio designed and produced a 2 way speaker using a 6.5" SEAS woofer and 1" focal tweeter (the same speaker is in it's 8th generation today) the speaker sounded great (I only got to hear versions III, 5, and 6 the last in 1997) but had an impedance curnve that included a dip to under 2ohms. A friend who heard these speakers tried to listen to them using his 200W Adcom GFA555 amp and the amp balked. A lesser rated amp (Krell KSA50) however had little problems. It was as clear an example i needed to understand the need for speaker-amp matching.

I found a good primer on amplifier basics here. Hope it helps.
Lenard Audio - Education - Amplifiers.

Originally Posted by nishantgandhi

Last I remember, either B&T or Navin had said that Blaupunkt GT4, Kenwood 840x and JBL GT5 are more or less the same.

So to put in it another way, which sealed subwoofer would run happily off that kind of power? EDIT: Also, does a sealed sub require more power than ported/BR/IB/free air?.. Hence, I thought a 10 inch sub would be less 'dominating' than a 12 inch one.

I dont know when I will ever get to install ICE in my car. It has already been 4 months of research!

The "60x2, 120W bridged" amps listed (Kenwood, Pioneer, JBL, Blau etc...) are more similar than different. When looking at paper specs of amplifers try to keep the following in mind.
1. THD/IM distortions at rated wattage
2. How stable is the amp at low impedances?
3. What is the function of the power output with respect to (nominal) impedance?
4. Over what frequency range has the amp been measured?

Amps ratings should really read something like this: 50W rms/4ohms (stereo) / 100W/4ohms (bridged) 20-20khz, THD < 0.01% at rated output. Another indicator (more ture for Class AB amps than Class D amps) is the weight of the amp and the size of it's power supply (usually rated in VA and not Watts).

If you have a small amp it will in all probablity be able to drive a lighter 10" woofer better than a heavy 12" woofer. The reason why I mention light and heavy is that today you find 10" woofers with a Mms of 100gms and 15" woofers with a Mms of 60gms so it is cone weight (and the strength of the magnetic circuit the voice coil is in) that matters along with woofer diameter.

Yes with a small amp and a lighter woofer one wont get the last 1/2 octave or so of bass (especially if the box is small) but what bass is there will be better defined and the subconcious mind will fill in the rest.

Ever hear a good small 6" woofer (like the Dynaaudio 17W75 or ScanSpeak 18W8xxx series) in a small monitor speaker style box? Notice that even with such a small speaker Stanley Clarke's bass is very discerable and one can actually hear the impact of when his fingers hit or slide on the strings? This is what you need to look for. Indian acoustic music is very demanding. Listen to the instruments live and you will hear what you need to listen for when you listen to them over a stereo.

I have heard good quality bass from ported, sealed, transmission lines, horns and even speakers that dont have boxes (Jamo R909 for example) dont fret about the design. Listen, feel, and listen again - to every instruemnt, loudspeaker, amplfier , CD player you can find. Every listen even if it to a pair of Pioneers powered by an Xplod amp can be a learning expereince.