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Old 4th June 2006, 15:22   #61
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Quote:
Originally Posted by santosh.s

Actually, our ears do have ability to percive stereo image at very low frequency as well. But how you transfer two independent sound waves to left and right years is the key. Even at 100Hz, the wavelength of sound is over 3 meter! you know what is the distance between your ears, of course its very small compared to this. At 20Hz the wavelength will become 5 times longer. So it is not possible to send independed bass signals to two ears without sending almost the same signal to the other ear, through distant speakers, no matter what setup you use. It can only be done by using headphones. Otherwise why should 5.1 and other advanced sound schemes sacrifice 2nd subwoofer, where the primary requirement is high fidelity 3D sound? Therefore be it home or car, as long as you are using speakers you need only one subwoofer, even for audiophiles
nice one Santhosh.

So what say kb?

Last edited by jkdas : 4th June 2006 at 15:23.
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Old 4th June 2006, 15:44   #62
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Ermmm... Do we have another guru in our midst???...

There was this time that the someone sat with me a mathematically proved that most car audio amps/speakers cannot do more than 10watt RMS Tops! ... (something to do with electrical energy being converted to sound energy and electrical and thermal efficiencies etc..a a bunch of other things) ... Must say the logic was sound!

Hence maybe there is another expalanation too... Lets hear a few more views!
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Old 4th June 2006, 16:28   #63
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Quote:
Originally Posted by kb100
Ermmm... Do we have another guru in our midst???...
wow, I am privileged to recieve this honor... but you know, I know very little about ICE! I have don't even have clear enough idea as to what all is available out there in the market, whats worth and whats not. I am yet to fit my very first car audio system in 5 months old baleno Thats partially because my wife cares a damn for music, for her its all waste of money and also because I am scared to go through "audo advice from gurus" thread... its so huge

Quote:
There was this time that the someone sat with me a mathematically proved that most car audio amps/speakers cannot do more than 10watt RMS Tops! ... (something to do with electrical energy being converted to sound energy and electrical and thermal efficiencies etc..a a bunch of other things) ... Must say the logic was sound!
very interesting, please PM me the link... you have stimulated my curiosity!

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Hence maybe there is another expalanation too... Lets hear a few more views!
Hummm... so you are thinking of me as somebody like the guy who claimed to produce petrol from some plant leaves or god knows what? just kidding... actually I would welcome any counter arguments which will definitely teach us all something new
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Old 4th June 2006, 18:54   #64
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I repeat what was said in Post #55

Hope the wait is not endless!!...

Last edited by kb100 : 4th June 2006 at 18:56.
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Old 4th June 2006, 19:51   #65
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KB100

Go for single box with a partition...period.

Subwoofers will operate in dedicated volume isolated from each other. Size and weight of the box is not a problem, iDQ´s are light and box just measures 28"L X 14"H X 10"H, which is quite manageable.

Santosh your explainations are valid. But listen to both configuration and you will percieve the difference.

In the end i will say "Hear" "Believe"

Last edited by Autophile : 4th June 2006 at 19:59.
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Old 4th June 2006, 20:19   #66
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Quote:
Originally Posted by Autophile
In-between two subwoofers playing stereo and mono, mono will be louder as the signal is summed, amplified and the two subwoofers are powered by identical signal, they are perfectly in phase in their entire bandwidth of bass reproduction.
If the subs are not in phase in stereo, and this owing to the nature of the recording rather than due to the relative placement of the subs, then it is to be expressly understood that the recording was intended that way in the first place. It is not our responsibility to correct that. But, why some recording engineer would like to have it that way is completely beyond me, and I'm sure that is not a very desirable effect. Causes could range from poor miking to bad recording studio/ location acoustics. The solution is to buy better produced music. A stereo subwoofer setup would gayly (ok it's spelt gaily Crap, i just have one more smiley left) bring this acoustic anomaly to your car.

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Ideally one should have stereo bass in the car (only SQ users) it complements the front stage and imaging very well. Lot of users has single subwoofers running mono and the box is ideally in one corner. Now listen to the familiar track with good musical bass sitting in the driver seat and then in the passenger seat the bass will not sound the same there will definitely be a difference, even if you call it as omnidirectional, difficult to localise. But it will not sound right.
In almost all cases, the phenomenon you describe is attributed to standing waves. Irrespective of whether stereo mono, or singular subwoofer, standing waves will occur unless the listening environment in concern is an anechoic chamber, the best of which will greatly minimize the effects on standing waves but yet not completely eliminate standing waves in sub-bass frequency.

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If you have stereo subwoofers this will not happen. It will be the same.
Nahin yaar, stereo, mono, or just one sub in the car, this will always happen. This will only not happen between two geometrically identical seating positions in the car such as if the sub is equidistant from the two listening positions in consideration and the triangle (triangle in case of one sub, it could be a rectangle or axially symmetrical trapezoid in case of 2 or more subs) comprising the two listening positions and the sub are symmetrically located along the axis of the car. Even then, it only means that the bass information perceived at these two locations are just identical, not perfect or devoid of standing waves.

Moreover, stereo separation by physically separating the 2 subwoofer drivers is not so easy in the car due to space limitations. Hence, the relative difference in distance between the subs is not so great when measured from the front listening positions to remarkably and accurate pin-point one of the two subwoofers. Additionaly, your recommendation of enclosure is of 28" length. Even if the subs are at the edge of the box, the center to center distance of the subs will be 16" for a subwoofer of 12" diameter. How separate is that compared to the listeners about 8 feet away? This is not my major argument though.

Quote:
This is the reason why the subwoofers are not used in the stereo setups in home audio. The integration between the speakers and subwoofer in home audio is very difficult. I have tried a lot of times from budget components to ultra high end, bottom line is it just does not work.
Large floorstanding speakers use large diamater bass drivers that play subwoofer frequencies in stereo, some with sparkling gusto. This is analogical to trying to mate two stereo subs with a pair of speakers in every conceivable way. For well-designed speakers, this always works. But of course, with the kind permission of the room. Therein comes placement. Results are bad when speakers are not placed properly and worse when subwoofers are detached from the mid-high sections. The worst scenario is having a sub near or behind your couch. The car environment takes the proverbial cake. Hence a case against stereo subs.
Quote:

On the other hand we can achieve that in car audio by using electronics for adjusting delay, crossover, level, eq in each driver (talking about active system). Even in passive system you can take care of delay, phase and eq to a certain extent but not as extensive as active system.
But why do you want to correct things that were intended to play wrong in the first place? This is the basis of your case for stereo subs in the first place.

Quote:
Try using 20Hz subsonic filter on the sub it will sound different with the filter on and off. The difference is noticable because you can hear the effect of filter at 20Hz
You would hear a difference if information on the track playing did exist at or below 20Hz. Even if it does, the primary reason for hearing the bass differently is because using the subsonic filter rids the amplifier of the burden of unnecessarily amplifying signals of such low frequencies, and quite a burden at that. I am not denying that humans cannot distinguish 20Hz frequencies, but the cause of the changed sound. Inarguably though, 20Hz is as omnidirectional as it gets for ears that are half a foot apart.

Quote:
Today companies are spending money in R&D of high frequency drivers capable of reproducing frequencies above 20Khz. Even there are dedicated super tweeters which are used to reproduce HF from 10-15Khz to 54Khz. Now if we go theoretically humans cannot listen above 20Khz but brain does recognises frequencies above that, one might not notice but it definitely adds to listening pleasure. If our listening band width is 20-20Khz why the hell do we need expensive supertweeters, preamps / amps with frequency response of 5Hz - 100Khz.
This debate could spark a whole new thread.

Time for my second smiley..

Last edited by Bass&Trouble : 4th June 2006 at 20:26.
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Old 4th June 2006, 20:23   #67
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Quote:
Originally Posted by kb100
Hope the wait is not endless!!...
THAT is the height of optimism! You poor sod - havent you learnt by now?

As I watch, things are getting murkier & murkier...
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Old 4th June 2006, 20:27   #68
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Quote:
Originally Posted by Bass&Trouble
If the subs are not in phase in stereo, and this owing to the nature of the recording rather than due to the relative placement of the subs, then it is to be expressly understood that the recording was intended that way in the first place. It is not our responsibility to correct that. But, why some recording engineer would like to have it that way is completely beyond me, and I'm sure that is not a very desirable effect. Causes could range from poor miking to bad recording studio/ location acoustics. The solution is to buy better produced music. A stereo subwoofer setup would gayly (ok it's spelt gaily Crap, i just have one more smiley left) bring this acoustic anomaly to your car.

Anything in the sub section, recorded wrongly, due to poor miking would result in (to put in plainly) stereo sub-bass. Otherwise its dead bloody center, thats the first thing you are taught.

So if this is an anomaly/poor miking or just a badly done mix, the only solution is to play the sub-bass in Mono. To make sure it's completely unlocatable, unpointable and every other wrong english word that leads to right bass.

I'm truly enjoying this debate. Truly. I know this thread is 5 stars already, I'd like to give it a sixth.

Are we really allowed 2 smileys now?

Last edited by Sam Kapasi : 4th June 2006 at 20:31.
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Old 4th June 2006, 20:35   #69
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Quote:
Originally Posted by Autophile
In the end i will say "Hear" "Believe"
Now now, that isn't gonna go down very well with LBM. At 150dB (evidently, all of it being bass), you can just feel the sound, not hear it. What say LBM?

Unfortunately, I can hear my mama calling everytime someone invites me to listen to cars that produce such disturbing spl numbers. Maybe the hear part is true after all!
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Old 4th June 2006, 21:21   #70
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Quote:
Originally Posted by Autophile
Santosh your explainations are valid. But listen to both configuration and you will percieve the difference.

In the end i will say "Hear" "Believe"
I agree, two setups can (or rather will) sound different because each of them can be a unique combination in terms of their response, interference, standing waves, resonance blah blah... But my point was that it should not be mistaken for stereo image recreation (from original recording) by bass frequencies, which should be limited to mid and high frequencies.
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Old 4th June 2006, 21:34   #71
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Quote:
Originally Posted by santosh.s
very interesting, please PM me the link... you have stimulated my curiosity!
You will have to MEET the guy... He is very much in Bangy ... and isconsidered a poineer in Car audio by everyone... and a legend by some!

PM me if you are intersted and I will be glad to give you his name and contact details!!
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Old 4th June 2006, 22:01   #72
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hello.. umm jst my 2 bits..1st smiley comming up ... i do a lot of work in the mastering department.. and having worked with people like lezz lewis .. shanker mahadevan , ar rehman .. etc.. all have come to our studio( purple haze @ bandra ) to work...
.. now.. we do use stereo bass .. but only in movies.. when we are doing 5.1 and above...not when we do music... when we master music.. agreed that we do make the bass in stereo... as in both channels.. left and right.. both .. but the Balance is always centered...(end output = MONO). ... but its just a rule that we all follow unless we do movies in 5.1... .. or unless the production department wants different......or unless the artist who made the track wanted different... but thats a very RARE case... 99 % of the stuff mastered is mastered with bass ( freq below 80 hz) as stereo but with the final outcome as mono as i explained (everything above 80 Hhz usually has panning effects on it.. hence you notice the pan effect out of the mid range and high's more).. so.. its all really about the MUSIC !!!!! hehehe.. Different generes have different ideas.. like trance.. its all ok.. do what you want !!! but you wouldnt finD shanker mahadevan DEAD ...doing half the stuff we trance guys do... .. so yeah.. its all about the music baby !!!!!!!
but as a personal choice.. id keep mono.. cause in a car.. bass which is Omni-Directional in any case !!!.. is just exactly that ... OMNI-directional.. cause the distances required to effectively percive left and right are tooo smalll.. and to add to that.. the fact that they are in a BOOT...
hmm all this is really enough to really spark off a new thread...
but yeah before anyone gets critical of this... all i am saying is.. its all done .. bass in stereo and bass in stereo which equals MONO.. and all kinds of variations are out there.. its part of the artists Creativity ....as to how path breaking he wants to be... but basically.. most of the music out there is like i explained...) bass as stereo=mono) .. this is just my view from the eyes of a engineer... i mean .. i make this nonsense... !!!!
heheheh hope this helped.. or confused even more.. let me know...
time for 2nd smiley...
BOOOOM

Last edited by Tool : 4th June 2006 at 22:08.
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Old 4th June 2006, 22:33   #73
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Excellent Tool, just the input we required, from someone in a studio.

When you say stereo bass for surround sound formats, I'm sure you mean that when the 0.1 isn't operational i.e. when you are using full-range speakers capable of rendering sub-bass frequencies. Right?
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Old 4th June 2006, 22:59   #74
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Quote:
Originally Posted by low_bass_makker
In a stereo setup if in a track there are drum beats in the left channel the sound will come in the left sub only. And the output will be reduced because only one sub is working. But if it was a mono output the drum beats would have came out of both subs. and the sound level would have been more.

Also if there is a stereo setup the imaging of the bass cannot be judge by the Listener because of the sound waves are in feet so he cannot aim them from where they are comming. ( In a car boot if there are two identical woofers are there , and one is playing one cannot tell which one is playing)

One more thing in a home theater there is normally one sub, so both the left and the right channel are present there.

So from my personal point of view the mono setup is much better than the sub stereo setup in CAR. But in home it can be different....

In a car install the sub of size like 10 or 12 inch cannot be installed in the front or the door. so they go in the back. But the 8 inchs can be installed in the front or the doors but then they dont go low enough to produce bass which 12 inches can produce.

If the sub is in the boot then do we need a stereo setup ?
Will one be able to identify which sub is playing in the boot left or right?
Even If it a hardcore setup...........
I think what I have said earlier is being repeated by everyone here in different formats. so again I would say the same as above. Rest I think KB100 will do what his GURU will tell him to do.......So let us stay out of this and let the Guru and Shishy do the talking.....





Quote:
Originally Posted by Bass&Trouble
Now now, that isn't gonna go down very well with LBM. At 150dB (evidently, all of it being bass), you can just feel the sound, not hear it. What say LBM?
Man If I play the subs in my car at full blast I cannot able to understand the vocals a bit so I have to reduce the same. About my achive 150db I think I will have to add to more more sub achive that. Rest whether it is stereo or mono I think It will nearly play 90% the same as commented by sam and tool.









Quote:
Originally Posted by Autophile
KB100

Go for single box with a partition...period.

Subwoofers will operate in dedicated volume isolated from each other. Size and weight of the box is not a problem, iDQs are light and box just measures 28"L X 14"H X 10"H, which is quite manageable.

Santosh your explainations are valid. But listen to both configuration and you will percieve the difference.

In the end i will say "Hear" "Believe"
from the above box size each sub will get 0.78 cuft which is the mean derived form the manufacture spec. that is from .55 to 1 cuft. But from my personal experience the later that is 1 cuft would be great as the small box will sound more toward the high freq that is near 50-70 hz and the bigger box will sound toward 30-50 hz . This i am sure of because I have measured the above with the help of a db meter playing sine waves in the car which include the cabin effect also.
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Old 4th June 2006, 23:09   #75
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Santosh and kb100, I have heard the “max RMS power” argument as follows: The car battery voltage is 12 V. Suppose your sub presents an impedance of 2 Ohms to the amp output. That means a maximum of 6 Amps thru’ the sub. So the maximum power any sub can draw is current*current*resistance = 72 Watts.
But I think high end amps use DC-DC converters to boost the supply voltage, so that higher output powers can be achieved as advertised. Hence the above argument may not hold in practice. Gurus pl correct me if I’m wrong.
Cheers
Reji
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