Go Back   Team-BHP > Under the Hood > In-Car Entertainment


Reply
 
Thread Tools Search this Thread
Old 23rd April 2009, 18:13   #1
Senior - BHPian
 
frankmehta's Avatar
 
Join Date: Mar 2006
Location: Mumbai
Posts: 3,866
Thanked: 2,231 Times
Default Difference between a Monobloc and 2 Channel Amplifier for the Subwoofer?

I have a 2 channel class ab amplifier that does 325w rms with both channels bridged. I use it to power my single voice coil subwoofer.
My question to all is, how much difference will a class d(or class ab, whatever) Monobloc making the same amount of power make, powering the same sub in the same unchanged setup? The question is with respect to the quality of the bass, the amount of bass, imaging and the control of the amp over the bass. Does it make ANY difference? I don.t think so, but i'd like it from the Gurus :-)
frankmehta is offline   Reply With Quote
Old 23rd April 2009, 18:15   #2
Senior - BHPian
 
greenhorn's Avatar
 
Join Date: Apr 2007
Location: TN-14
Posts: 6,839
Thanked: 1,318 Times
Default

here ya go, along with the obligatory message to search before starting new threads
https://www.team-bhp.com/forum/ask-g...tml#post862395

Last edited by greenhorn : 23rd April 2009 at 18:17.
greenhorn is offline   Reply With Quote
Old 23rd April 2009, 18:17   #3
Senior - BHPian
 
quickdraw's Avatar
 
Join Date: Mar 2008
Location: New Delhi
Posts: 1,008
Thanked: 1,285 Times
Default

This is the kind of question n00bs like us would ask guys like you.

I cannot comment on very elobrate aspects but will say in all honesty have always opted for the monobloc because its "taylor made" for the job. And that in my books will be better then anything else in every aspect.
quickdraw is offline   Reply With Quote
Old 23rd April 2009, 18:18   #4
Senior - BHPian
 
abhinav.gupta88's Avatar
 
Join Date: Sep 2007
Location: Delhi , India
Posts: 4,087
Thanked: 308 Times
Default

Aha.
I knew something was fishy.
Frank upgrading to mono?
abhinav.gupta88 is offline   Reply With Quote
Old 23rd April 2009, 18:26   #5
Senior - BHPian
 
frankmehta's Avatar
 
Join Date: Mar 2006
Location: Mumbai
Posts: 3,866
Thanked: 2,231 Times
Default

Thanks for the link greenhorn. It was virtually impossible to fine this post in the link using the search function. But i've got an overall idea. My query is still not answered completely. Will a mono make a difference in my setup? And Abhinav, there's no mono in this time's upgrade. I'm just trying to gauge the nuances of this 2ch vs mono funda
frankmehta is offline   Reply With Quote
Old 23rd April 2009, 18:45   #6
Distinguished - BHPian
 
Technocrat's Avatar
 
Join Date: Feb 2004
Location: Mid West
Posts: 14,900
Thanked: 2,492 Times
Default

Posting it here for future reference

Quote:
Originally Posted by navin View Post
Quote:
Originally Posted by greenhorn View Post
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.

Quote:
Originally Posted by nishantgandhi View Post
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.
Technocrat is offline   Reply With Quote
Old 23rd April 2009, 19:01   #7
Senior - BHPian
 
frankmehta's Avatar
 
Join Date: Mar 2006
Location: Mumbai
Posts: 3,866
Thanked: 2,231 Times
Default

I was alread impressed by Navinji's knowledge. This post just raised that awe a couple of notches higher.


Ps: i read again, i have a very light woofer. How does all this apply to me? Can someone explain this to me in my context pls?
frankmehta is offline   Reply With Quote
Old 23rd April 2009, 19:10   #8
Senior - BHPian
 
headers's Avatar
 
Join Date: May 2006
Location: Greater Chennai
Posts: 4,589
Thanked: 454 Times
Default

looks like you would have to go for a lighter amp frank. I'm a newbie as much as you are and thats my understanding from reading the above.

Navin has gone up a few notches IMO. Great explanation!
headers is offline   Reply With Quote
Old 23rd April 2009, 20:03   #9
Distinguished - BHPian
 
jkdas's Avatar
 
Join Date: Sep 2005
Location: Thiruvananthapu
Posts: 9,661
Thanked: 1,389 Times
Default

Forget about the power part, makes a big difference in quality.

Surprised that you have a 2 channel for sub! Missed that part somehow!
jkdas is offline   Reply With Quote
Old 23rd April 2009, 20:26   #10
Senior - BHPian
 
Join Date: Mar 2006
Location: Faridabad
Posts: 6,814
Thanked: 294 Times
Default

Baseline...we cannot compare the two....Both are very differnt things. Franks if you have any models to choose from then we can help.

A normal d-class when compared to a good 2-channel can fail. But again it all depends on which model you are choosing from.
low_bass_makker is offline   Reply With Quote
Old 23rd April 2009, 20:34   #11
Senior - BHPian
 
Join Date: Mar 2005
Location: N.A
Posts: 6,834
Thanked: 1,503 Times
Default

Gods of all things Cold

Is there such a thing as a 3 channel amp? I was suggested one of these things for a simple setup in the Defender. I've personally never heard of such a thing, but hey I never knew of Monoblocks before they started making ICE here.
Steeroid is offline   Reply With Quote
Old 23rd April 2009, 20:35   #12
Senior - BHPian
 
frankmehta's Avatar
 
Join Date: Mar 2006
Location: Mumbai
Posts: 3,866
Thanked: 2,231 Times
Default

I am not keen on making the jump. Still not convinced how much difference it can make. My amp in question is an rf old school amp and produces a good 250w of true power. I see no point in having a mono block do the duty for a single, svc sub. Its a luccent we're talking about. Its highly musical and performs well even when supplied with much lesser power. A mono would be overkill in this case, wouldn't it?
And for the last time guys, i'm not looking to buy one. I'm weighing my options and trying to point the weak links in my setup. I don.t have money to buy a new amp right now. My question remains the same, what quality of the bass will change on having a mono instead of a 2 channel. And why not the dedicated 2 channel for the sub?
frankmehta is offline   Reply With Quote
Old 23rd April 2009, 22:32   #13
Senior - BHPian
 
govigov's Avatar
 
Join Date: Oct 2007
Location: Cochin!!!!!
Posts: 1,314
Thanked: 431 Times
Default

what do you mean by the damping factor?
govigov is offline   Reply With Quote
Old 23rd April 2009, 22:40   #14
Senior - BHPian
 
Join Date: Mar 2006
Location: Faridabad
Posts: 6,814
Thanked: 294 Times
Default

Quote:
Originally Posted by govigov View Post
what do you mean by the damping factor?
Ability of a amp to control the sub...

A little more on the same...damping_factor.pdf

Frank stay with your 2 channel it would be more than enough for now...No need to spend more...First get the things which you have planned then think about it later.
low_bass_makker is offline   Reply With Quote
Old 23rd April 2009, 22:42   #15
Senior - BHPian
 
PatienceWins's Avatar
 
Join Date: May 2007
Location: Bangalore
Posts: 2,159
Thanked: 261 Times
Default

There is difference in quaity with a Monobloc.

I was skeptical to invest more money on a monobloc instead of bridging two channels of my 4 channel or using a seperate 2 channel amp. I am using a Class D Monobloc and it takes id sub to perfection.
I am happy to see my friends change their opinion after listening to my setup. Initially when they hear the cost, they say I am crazy.
PatienceWins is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search


Similar Threads
Thread Thread Starter Forum Replies Last Post
Needed Advice on Monobloc abhinav.gupta88 In-Car Entertainment 152 20th March 2009 11:31
alpine 2 channel amplifier and wire guage/properties query? makanaka In-Car Entertainment 18 10th March 2009 13:19
2 channel or 4 channel amp harry2223 In-Car Entertainment 14 19th February 2008 22:08
Sony 4 channel amp' and Pio subwoofer for sale rjstyles69 Shifting gears 10 14th August 2007 19:18
Blaupunkt Subwoofer and Kenwood Amplifier for sale general_neo Shifting gears 7 25th December 2005 13:32


All times are GMT +5.5. The time now is 07:30.

Copyright 2000 - 2017, Team-BHP.com
Proudly powered by E2E Networks