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-   -   2 Subs - Dual Mono or Stereo - "Kb ka dB" (https://www.team-bhp.com/forum/car-entertainment/13888-2-subs-dual-mono-stereo-kb-ka-db-2.html)

:OTI just got some old billboard number from the year 1970-1989(there are nearly 2000 songs. Man some songs in them are really good. Remeber me of old times.On DD there used to come a program called HOT TRACKS we use to record them. Now as I am listening to the songs I am really enjoying it.

Yeah man, early on I was raised on ABBA, Boney M, Country music, ghazals and film music. then I was fed a steady diet of British pop and American Rock. Then came Rap, Hip Hop, R&B. Then came in Tehno, Jungle, Trip hop, Asian underground, blah blah blah... the list is very long. And it keeps growing...

Music is the reason I got into audio. Not the other way around.

Hear hear....

Hear hear (I had to do that twice because the message was too short)

rl: I did something similar to that once and a bloke told me "that isn't going to help you increase your post count"

Where's Navin Saahab, doesn't he want to dig his heels into this topic?

Did someome call me.....I was under the impression that only gurus, maharajas and other such supernatual folk were entitled to comment on this thread.

1. in a car in most applications (even some that are "almost" purist) mono bass will suffice. However this is provided the amp is suitable. I think amp sutiability plays a more important role here than the ability to TA the bass to the front speakers or for some genres of music where the instrument(s) used span the bass and the midbass and then there can be integration issues.

In my Octavia I use stereo bass but in my wife's Sail I use mono. However I might move to mono bass in my Octy adn do not think I would notice the difference under most circumstances.

In short first determine amp suitability and then determine the types of music you listen to and only then decide if you need stereo bass. if not go mono.

2. Home Theater is a different cuppa-tea. The .1 channel carries specific bass information in mono. You can drive multiple woofers of this channel but they will be all reproducing the same signal. I prefer to use multiple woofers at home driven of the .1 ch even though it is mono as it reduces th effects of room nodes.

Ok report hai ji. But navin ji we are talking of the stereo not 5.1, In stereo there is one left and one right. I can say earlier I had woodstock speakers at home they had one tweeter one midrange and a 12 inch woofer. Man though they are a economical but they sound very good . I have placed them far apart like in the corner of the room for the best stereo imaging. In this type of setup the bass is in stereo format.and the listener can clearly make out from which channel the sound is coming. But again in car the bass imaging cannot be judge so no use of it there......

Yes, the amp, subs, front stage etc are assumed to be top notch. Else this discussion is moot. Its like driving an M800 but having a discussion on G-force effects on 200+ kmph driving.

KB100, since this was your query, and I know what equipment is going into your car, how its going to be installed, what music you listen to... I can tell you that though you WILL be able to hear a difference between stereo and mono sub output, you may just prefer mono because it will be louder.

Why is it being reiterated that mono will be louder? I am not able to understand this. Like LBM says, Please shed some light on this topic!

Well its simple, and I'm surprised YOU asked.

Bass levels are never equal in both channels. A summed output will contain the same combined output and thus both subs will get equal output at all times, compared to a Stereo setup where each sub will have its own information and usually, one channel will have more bass information than the other.

Thus, the summed mono setup will always be louder.

BTW, all of this is my opinion. Its not necessary for all to agree. Lets just leave it at that...

GUNMAN...

I know what you think... Afterall this was your suggestion and we have already actioned it too!!... But I thought this was an interesting topic that had never been discussed before on the forum.. and info that emerges may be beneficial to all.. I for one have already have been benefited!!

That's Ok, atleast I meant to ask YOU :)

So let's say the level of bass in the left channel pre-out is X units, and the level of bass in the right channel pre-out is Y units. Let's assume we're using a 4-ch amplifier to drive the subs.

Why 4-ch amp? Why not monoblock or 2-ch amp? Using 1 monoblock to drive 2 subs in stereo is not possible. And likewise, if you want to drive 2 subs with a 2-ch amplifier, practically you want to drive them in bridged mode, otherwise the unbridged output is itself going to result in lower loudness, irrespective of the input signal varying between left and right or not.

So you either switch the 4-ch amp to 2-ch input mode, or you use Y-adapters to give inputs to all 4 input channels of the amp.

So, in stereo mode, the amp's input stage will see 2X + 2Y. Since the amp's gain will be constant for a given amp, assume that to be unity, so the output will be 2X + 2Y too.

In bridged mode, each of the input channels will carry a signal of strength (X+Y)/2. They won't be simply X+Y, this would mean that the signal strength in each individual channel doubles when you switch from stereo to mono. So a 4V pre-out HU would put 8V to the pre-out in mono, i find this absurd.

So total output (again, gain is unity) is 4 x (X+Y)/2 = 2X + 2Y

Identical to that in stereo? Wrong? Please shed some light on this issue. :)

B&T, you misunderstood what Im trying to say. I wasnt talking out preamp output levels at all...

In a stereo setup, bass levels will differ in L & R channels. So when L channel may be putting out more bass information than R channel, one sub will be working more than the other.

In a summed mono situation, BOTH subs will be working equally. Instead of one sub working more than the other, you will have both working equally. That means more cone surface area and more air moved. Hence louder. Simple!

In both these instances, I am talking about a 2ch amplifier driving each sub separately off each channel. No bridging, no 4 channels.

Bro, 2-ch/ 4-ch same thing. 4-ch was just to assume a bridged amp driving the subs, otherwise some dorks would ask why you are not running subs on a bridged output etc?

Anyway, even in stereo mode on a 2-ch without bridging , if the output of the left channel and the right channel differ, it does not translate into meaning that since in stereo one was louder than the other, now both will be as loud or marginally louder or whatever of that sort. The channel which was louder will play softer and exactly equal to the arithmetic mean of the 2 channels, while the channel that was softer will play louder than in stereo mode, again exactly equal to the arithmetic mean of the two levels, and consequently, the same level as the other sub. The overall output (in terms of amplitude and amplitude only)will not change.

Surface area is same sir! Same 'Do Baara Inchi'. Same amount of air moved, only two guys equally sharing the work between them!

Well I would say you're probably right there... But.... we tested this through the Clarion HX-D2 HU as it has a stereo sub / summed mono option. For a while we had 2 x 12"ers in there... and the mono option got marginally / noticeably louder... maybe its just that stereo subs suffer from a bit of phase cancellation, and going mono changes that... B&T can you think of anything else that would explain this.

BTW, since this is relevant to this discussion, I remember having read somewhere that most current mainstream HUs have a summed mono sub output by default. That is, the sub information derived from the signal is processed in a mono manner. So both the outputs have the same mono output anyway. That would also explain why a lot of people cant hear a difference between stereo / mono subs.

I have read some place in a forum about the sound myth`s

"If we add a similar driver like for eg If there is one 12 inch sub and we add another same drive with same amplification the sound would get double."

The above statment is 100% wrong it was said that there will be 6db increase if the sub are fully in phase. and approx 3db if they are little out of sync.

Now in a mono setup the sub will perfectly in phase but in a stereo setup they will be swinging acording to the track in which there might be some phase change. So in a stereo setup the sound will be less and in a mono it will be more becasue both the subs will be playing.....................

One more thing For example if in a track the whole music is in on right channel and the vocals are on the left channel. So the amount of bass would be less than in a stereo setup be cause only 'ek Baara Inchi' will be playing not 'Do Baara Inchi.'