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Are Two Sub Woofers must for Perfect Stereo?

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sunder

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Hello friends, In a stereo system , a single sub woofer is adequate? or Is it the perfect set up with a sub for each channel ? Any distinctive difference can be heard? When a preamp has only one sub out, how to feed for two subs? Please share your ideas and experiences. Thank you.
 
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I think a stereo system is normally void of subwoofer. Only two channel. However it depends upon listening taste of the individual. I listen to some music with only two channel and some music with my two speakers and my sub. Depends really on what kind of music one listens to as well.

Two subs has it pros and cons. If not integrated properly with your system and room, could leave you with a poor sounding system. I’m just reading up on this too, so my knowledge is limited.
 

sunder

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Since the two channel speakers are full range drivers, we get the LF not as of from the two way enclosure. Further, for the old Indian film songs, it's needed some Bass enhancement. Thanks .
 

efernand1

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A sub would provide that bass enhancement....you need to look for a sub which can perform below the frequencies that is being outputted by the front / full range speakers...

Professionally if you go for Band shows or concerts.....Bass driven from BIN speakers is mono......the signal is sent in a relay fashion to each other.....

I am a huge music fan and do listen a lot using my AVR on Stereo mode......front speakers kept as large.....and sub adds a bass envelope presence which is very good and nice.....
 

yogibear

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I heard a huge difference when added two identical subs, one to each channel. But you must get the phases right. Hence crossovers with adequate options is must.

If done right and if you have a good space, it makes a huge difference.
 

sud98

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I am a huge music fan and do listen a lot using my AVR on Stereo mode......front speakers kept as large.....and sub adds a bass envelope presence which is very good and nice.....

Is that a typo, how would you hear anything in the sub if you are playing two channel music and front speakers kept at large. Shouldnt they be kept at small to make bass management kick in.
 

sunder

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A sub would provide that bass enhancement....you need to look for a sub which can perform below the frequencies that is being outputted by the front / full range speakers...

Professionally if you go for Band shows or concerts.....Bass driven from BIN speakers is mono......the signal is sent in a relay fashion to each other.....

I am a huge music fan and do listen a lot using my AVR on Stereo mode......front speakers kept as large.....and sub adds a bass envelope presence which is very good and nice.....


If two LF signals of the music come at the same time from left & right channel , then, will the relay suppress one channel's LF signal ? and will only allow one channel's LF to the Sub? Thanks.
 

efernand1

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Usually for professional outdoor setups....everything is analog....in all cases a signal is taken from Left channel of Mixer (considered mono) and fed to amp which inturn is hooked to a Bass Bin....

If you have exclusive 2 signals (L & R) coming out ...you can have dedicated amps and woofers that can be used as left and right......as mentioned by FM, it can be tricky for a room setup and a lot of trial and error can go in ensuring a proper setup....
 

efernand1

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Is that a typo, how would you hear anything in the sub if you are playing two channel music and front speakers kept at large. Shouldnt they be kept at small to make bass management kick in.

No typo my friend.....check AVR settings.........Bass Management .....LFE + Main.......then everything works..... ;)
 

abhi33

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LFE Singnal is mono, Sub is fed with low frequency signals of all channels, it can be either stereo or 5.1. So for stereo you may not need two subs instead choose the better quality Subwoofer which blends seamless with both left and right channels.
 

sunder

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LFE Singnal is mono, Sub is fed with low frequency signals of all channels, it can be either stereo or 5.1. So for stereo you may not need two subs instead choose the better quality Subwoofer which blends seamless with both left and right channels.

Hi abhi33, in the two channel music content, if the LF was recorded from the both channels by the proper stereo mike, then a single Sub woofer can manage the two separate drum sounds of two channels? Will any clashing or congestion really occur? In this place, will a sub for each channel be helpful? Thank you.
 

abhi33

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Sunder, here is some information for the question -One or Two Subwoofers for Stereo Music System?

Most of stereo systems have two main speakers, yet we have only one subwoofer. Why not two subwoofers as well? In some situations there can be advantages to having two (or more) subwoofers, but in general one is usually sufficient. The reason for this is connected to the fact that, for frequencies below about 700Hz, our sense of hearing measures the phase difference between a sound arriving at each ear, whereas above this frequency it uses mainly level differences. Out of doors, our ability to determine a sound's direction remains quite accurate down to remarkably low frequencies, but this ability collapses when listening indoors. Sources generating low-frequency sounds (below about 100Hz) tend to do so more or less omnidirectionally (the sound wave travels from the source in all directions) because the wavelength of sound is usually larger than the object itself. When a low-frequency sound is generated within an enclosed space, the spherical sound waves created will reflect off the boundary surfaces of the room to arrive back at the ears with a multiplicity of phase variances, due to path-length differences. This confusion of signals makes it impossible for the ear and brain to extract a reliable phase difference, so normal directional acuity fails.

So in theory, since you can't tell where the low frequencies are coming from in a room, one subwoofer will be entirely sufficient. The harmonics of the bass notes will be reproduced by the satellite speakers — which typically start to take over above about 90Hz — and these will provide plenty of directional information through phase and level differences, in the usual way. So, although the bass itself is folded down to mono, the impression of stereo imaging is actually preserved perfectly satisfactorily.

This theory is all well and good, but I often hear people comment that they can hear where a subwoofer is placed in the room. This isn't because of some special acoustic ability on their part, though —rather, it is because of the poor performance of some subwoofers! Designs constructed at a low cost, employing inferior drivers, and those designed to favour efficiency above all else, tend to generate a lot of 'out of band' noise — lots of harmonic distortion and audible port noises, or other artifacts. These occupy the mid-frequency range, which not only makes their position easily detectable, but also obscures and masks the critical mid-range frequencies from the satellite speakers. So adding a cheap subwoofer to quality satellites will actually tend to make the system less rather than more accurate.

A good subwoofer needs to have a very linear driver (which is expensive), an accurate and powerful amplifier (which is expensive), and a well designed and built cabinet (which is... expensive).
 

elangoas

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I will put it from my understanding..

In a stereo system , a single sub woofer is adequate?

Regardless of whether a stereo content (2.0) has low of 20 (or) 40 Hz, a subwoofer would produce more lows efficiently than FS/BS ..

If one sub is good, then two subs are said to tame the peaks at your listening position.. By placing two (or) more identical subs in ideal locations in your room, it would help acoustically to "flatten" the response at your listening position.. Which otherwise would be very difficult to do any treatment for bass < 100Hz..

or Is it the perfect set up with a sub for each channel ?

Don't think it is the right solution.. But with bass management, a summed mono response from both Left & right channels is then diverted to sub(s)..

Any distinctive difference can be heard?

In my room, i have used stereo in (2.0 - FS) and now in 2.2 (Dual identical subs).. 2.2 is more satisfying.. Feel it yourself in any FM place if one has it..

When a preamp has only one sub out, how to feed for two subs? Please share your ideas and experiences.

You can use a 1 RCA to 2 RCA Adaptor on the Pre amp sub-out.. You can then connect to two subs conveniently..
 

arj

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Hello friends, In a stereo system , a single sub woofer is adequate? or Is it the perfect set up with a sub for each channel ? Any distinctive difference can be heard? When a preamp has only one sub out, how to feed for two subs? Please share your ideas and experiences. Thank you.

HI Sundar my summary experience having played around winth single, dual and no subs
1. A good subwoofer ie one that can be articulate well at sub 60hz only enhances the music but if the sub is not able to do that it makes it worse
2. a subwoofer must be dialled in properly in the room , and it is not easy, else it will not sound good and you are better off without one
3. Dual subs are better than a single sub as they cancel out some of the standing waves and 4 subs are even better but a single high quality sub is better than any no of lower quality dual sub. ( quality defined by the quality of bass and not quantity and ability to reproduce the lower harmonics of human voices)
 

sunder

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I will put it from my understanding..



Regardless of whether a stereo content (2.0) has low of 20 (or) 40 Hz, a subwoofer would produce more lows efficiently than FS/BS ..

If one sub is good, then two subs are said to tame the peaks at your listening position.. By placing two (or) more identical subs in ideal locations in your room, it would help acoustically to "flatten" the response at your listening position.. Which otherwise would be very difficult to do any treatment for bass < 100Hz..



Don't think it is the right solution.. But with bass management, a summed mono response from both Left & right channels is then diverted to sub(s)..



In my room, i have used stereo in (2.0 - FS) and now in 2.2 (Dual identical subs).. 2.2 is more satisfying.. Feel it yourself in any FM place if one has it..



You can use a 1 RCA to 2 RCA Adaptor on the Pre amp sub-out.. You can then connect to two subs conveniently..



elagoas, thank you for shared your experience. I think , you mentioned about the 'Y' adaptor (1 RCA to 2 RCA) . Regards.
 

sunder

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HI Sundar my summary experience having played around winth single, dual and no subs
1. A good subwoofer ie one that can be articulate well at sub 60hz only enhances the music but if the sub is not able to do that it makes it worse
2. a subwoofer must be dialled in properly in the room , and it is not easy, else it will not sound good and you are better off without one
3. Dual subs are better than a single sub as they cancel out some of the standing waves and 4 subs are even better but a single high quality sub is better than any no of lower quality dual sub. ( quality defined by the quality of bass and not quantity and ability to reproduce the lower harmonics of human voices)

Dear arj, thank you for the inputs. Yes, I should be careful on the spec. & the quality when I select the sub. Thanks . Regards.
 

elangoas

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single high quality sub is better than any no of lower quality dual sub. ( quality defined by the quality of bass and not quantity and ability to reproduce the lower harmonics of human voices)

I have seen more of this similar suggestion for sub-woofer recommendation..

Quality of bass & Quantity of bass
- Someone having lil to NO experience with sub-woofers would find it hard to distinguish.. Almost impossible to judge..
 

sunder

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Sunder, here is some information for the question -One or Two Subwoofers for Stereo Music System?

Most of stereo systems have two main speakers, yet we have only one subwoofer. Why not two subwoofers as well? In some situations there can be advantages to having two (or more) subwoofers, but in general one is usually sufficient. The reason for this is connected to the fact that, for frequencies below about 700Hz, our sense of hearing measures the phase difference between a sound arriving at each ear, whereas above this frequency it uses mainly level differences. Out of doors, our ability to determine a sound's direction remains quite accurate down to remarkably low frequencies, but this ability collapses when listening indoors. Sources generating low-frequency sounds (below about 100Hz) tend to do so more or less omnidirectionally (the sound wave travels from the source in all directions) because the wavelength of sound is usually larger than the object itself. When a low-frequency sound is generated within an enclosed space, the spherical sound waves created will reflect off the boundary surfaces of the room to arrive back at the ears with a multiplicity of phase variances, due to path-length differences. This confusion of signals makes it impossible for the ear and brain to extract a reliable phase difference, so normal directional acuity fails.

So in theory, since you can't tell where the low frequencies are coming from in a room, one subwoofer will be entirely sufficient. The harmonics of the bass notes will be reproduced by the satellite speakers — which typically start to take over above about 90Hz — and these will provide plenty of directional information through phase and level differences, in the usual way. So, although the bass itself is folded down to mono, the impression of stereo imaging is actually preserved perfectly satisfactorily.

This theory is all well and good, but I often hear people comment that they can hear where a subwoofer is placed in the room. This isn't because of some special acoustic ability on their part, though —rather, it is because of the poor performance of some subwoofers! Designs constructed at a low cost, employing inferior drivers, and those designed to favour efficiency above all else, tend to generate a lot of 'out of band' noise — lots of harmonic distortion and audible port noises, or other artifacts. These occupy the mid-frequency range, which not only makes their position easily detectable, but also obscures and masks the critical mid-range frequencies from the satellite speakers. So adding a cheap subwoofer to quality satellites will actually tend to make the system less rather than more accurate.

A good subwoofer needs to have a very linear driver (which is expensive), an accurate and powerful amplifier (which is expensive), and a well designed and built cabinet (which is... expensive).


Dear abhi33, thank you for the convincing explanation. I can understand about the phase difference & the off the boundary reflections. So that may be the reason, most of the subs are with down firing baffle. Thanks . Regards.
 

Kannan

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it all depends in the source output. Some sources, rare though will have separate subwoofer outputs for left and right channels. But the most common is the monoaural single subwoofer output. Even this can be split and fed separately to left and right channels.

Yes, two dedicated subs will technically be superior to a single one, but that much more difficult to place and integrate. A single subwoofer is the most practical, in terms of integration, cost and most importantly space.

In my setup I have used a single sub kept at the center. I don't have a dedicated sub out on the source, so xo is set on the active subwoofer and I have done the integration with my ears with respect to matching sound level, crossover and phase with my bookshelf speakers.

Similarly in my car audio, due to constrain of space and power, I have used two 7 inch midbass in an isobaric configuration as a subwoofer. It is in the boot and powered by a 50 watt RMS TPA3116D2 board. The integration is done on my active Eclipse head unit
 

arj

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I have seen more of this similar suggestion for sub-woofer recommendation..

- Someone having lil to NO experience with sub-woofers would find it hard to distinguish.. Almost impossible to judge..

Its not difficult to learn if one is so inclined.. eg listening to vocals on a sub with max cuttoff can give a very good indication of the quality of the driver and amp
 
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