# subwoofer near monitor???



## arcticflare (Feb 24, 2005)

Is it true that the subwoofer must not be placed near the monitor. if so what is the safe range that can be maintained between the two?


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## busyanuj (Feb 24, 2005)

yes, the powerful magnet inside the subwoofter interferes with the monitor.

keep the subwoofer atleast 3 feet away from the monitor.


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## Tech&ME (Feb 24, 2005)

The subwoofer is not magnetically shielded and should not be placed near the video displays.  The subwoofer doesnot necessarily have to be placed in any particular relationship to the satellites since subwoofer contains no stereo information and sound is non-directional usually.  Placing the subwoofer on the floor close to the wall provides maximum bass efficiency.


And btw. why did u post the same topic two times ????


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## pradeep_chauhan (Feb 24, 2005)

The best idea is to use the sub woofer as a side table to keep your heavy stuff say the UPS this way its away from the PC and at the same time held down by the weight of the stuff on top of.


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## Tech&ME (Feb 25, 2005)

pradeep_chauhan said:
			
		

> The best idea is to use the sub woofer as a side table to keep your heavy stuff say the UPS this way its away from the PC and at the same time held down by the weight of the stuff on top of.



Wht r u suggesting Mr chauhan ?? are you suggesting to either keep the UPS on top of the subwoofer or vice-versa ???? In either of the cases this is not a good idea i guess. Instead what would be better if the subwoofer is placed on the right hand side of the table on the floor and provided that the CPU is palced on the table top on the left side and the UPS on the same left side but on the floor. This will keep all the things clear off from each other and will not interfere.


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## pradeep_chauhan (Feb 25, 2005)

I mean to say use the sub woofer as a side table. keep it on the floor and keep the UPS on top of it. It depend on how big the sub woofer is. I ahve a 12 " deive sub wooker that is 2.5 feet cube and i do the same things. 
Why is it not a good idea?


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## Nemesis (Feb 25, 2005)

d00d....y would u put anything on top of it???? so what if it's big??? its not as if the sub will fly away or something that u need something on top of it....what abt the UPS heating up???? just put the sub in some corner of the room against the wall....best performance....


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## cooljeba (Feb 25, 2005)

if the monitor display messes up just degauss it 

..:: peace ::..
Jeba


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## klinux (Feb 25, 2005)

@/atartic  : which model speakers u got ??? how big is ur room ? If u got a dig cam , just take a few snaps of ur speakers/woofer and 360 degree of ur room / might be able to help u out more on positioning of the speakers . This is not vaasthu or anything . Think of the as "Scope for Improvement" or "While you were Offline"


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## theraven (Feb 25, 2005)

man it doesnt matter
what kinda freak wants the sub at face level/monitor level ?
a sub is MEANT to be placed on the floor .... a corner ....even a few cm's OFF ground ..
placement varies from subjective sound experiences to models and different speakers..
however NO SPEAKER system every makes anyone place the sub at ur face level ...
there is absolutely no point
SUAVE man tell him something !


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## Tech&ME (Feb 25, 2005)

pradeep_chauhan said:
			
		

> I mean to say use the sub woofer as a side table. keep it on the floor and keep the UPS on top of it. It depend on how big the sub woofer is. I ahve a 12 " deive sub wooker that is 2.5 feet cube and i do the same things.
> Why is it not a good idea?



What kinda man r u ???? Don't u have some common sense ??? Man doesn't your UPS heat up, and who the hell told u to put that thing on top of the sub woofer man, don't u read the manuals, your SPEAKER SYSTEM (what ever make and size they are) must have come with some sort of "Installation Guide / Manuals, etc" they contain information about the "Proper Placement with some diagrams in some manuals for best performance " consult one man.


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## klinux (Feb 25, 2005)

FLASH NEWS : Speaker placement , defines the man u r !!! 

Come on , anyone can make mistakes or in this case , trying out something kreative . even i just realised i have my woofer placed just below the monitor with a steel plate alone blocking the 2 . anyways  , pradeep can check out good computer tables . Chennai guys can check out DAMRO's computer tables . Factory seconds , around 3500 Rs. Original around 5k . Not much difference , but the wood is beautiful .


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## pimpom (Feb 25, 2005)

Not all sub-woofers are created equal. Some have magnetic shields and some don't. Some can be placed right next to the monitor without any ill effect, while some have to be placed some distance away.

Some sub-woofers produce more interference to the monitor from the power supply transformer than from the speaker's permanent magnet. If the interference is caused by the transformer, it will generally produce moving wavy distortions to the display.

Whatever the source, interference from the sub-woofer will seldom, if ever, cause permanent damage to the monitor. So it's safe to experiment and find out the minimum distance you have to keep between the two.


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## klinux (Feb 25, 2005)

do those heavy huge wooden casing protect other objects near woofers . are there any other material can be used to reduce harmful effects ?


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## pimpom (Feb 25, 2005)

Wood has no effect on the magnetic field radiated by either the speaker magnet or the transformer.

Shielding can be provided by a magnetic material such as a sheet of iron. But a thin sheet of iron such as tinplate will not be very effective, and steel can become permanently magnetized so that it may itself cause interference. A thick sheet of soft iron or special magnetic alloy such as mumetal will be ideal.


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## klinux (Feb 25, 2005)

what abt aluminium foil ??? its thin and flexi , plus might give a good look to ur speaker box , if cut out correctly .


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## pradeep_chauhan (Feb 26, 2005)

Tech & ME 
I  fabricate my own 5.1 system and there is no heat /  over heating problem with my ups i use a apc & tvse ups. There is nothing wrong there. dear, dont just shoot of. Think logicaly and cool A sub woofer used as a side table is an efficent way of saving space. More over If you dont like my idea please feel free to keep the sub woofer in your lap for all i care.
The 5.1 system that i fabricate use the LM 3886 in bridge mode driving a bolton 12 " drive The enclosure is a close baffel 2.5feet square. The power output of the sub woofer is 100W rms. 

Klinx 
For shielding we have to use a ferrous material Aluminium will just not work


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## pimpom (Feb 26, 2005)

klinux said:
			
		

> what abt aluminium foil ??? its thin and flexi , plus might give a good look to ur speaker box , if cut out correctly .


Al foil is no good as a magnetic shield. It will do fine as a shield to block out the electrical component of an electromagnetic field such as for protection against unwanted RF radiation, but not for the magnetic component.

The rule is : to block an electrical field you need a good electrical conductor. To block a magnetic field you need a magnetic material.

To be more accurate, the shield blocks the field by providing an easy path to flow in, that is, an electrical or magnetic short-circuit.


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## Tech&ME (Feb 26, 2005)

pradeep_chauhan said:
			
		

> Tech & ME
> I  fabricate my own 5.1 system and there is no heat /  over heating problem with my ups i use a apc & tvse ups. There is nothing wrong there. dear, dont just shoot of.



Well Pradeep I didn't mean to offend you dear, I was just thinking about the damage it could do to your speaker system in a long run. Btw. If u have fabricated and have used concrete measures to ensure that your speaker system (sub woofer) does not damages itself then there is no problem in keeping the UPS on top of it. 

But, I still amazed man, I have never seen anyone do this in my friends circle and other people whome I know. Neither I heard about such an setup anyplace...... Hope that sounds good ya. Nothing offending Man, cool down!!!


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## klinux (Feb 26, 2005)

since we are in the topic of speakers , Whats the easiest way to make an amplifier . 

I have a soundblaster vibra 16 isa card with my p1 , i attached creatives and a pair of old panasonic 350watts speaker (big ones) . i get good sound and can control the volume right from there . But when i attach those speakers to my Soundmax integrated on asus board , can hardly hear any sound . I use Frontech 4.1 for the integrated . I suppose the newer sound card/devices need amplifiers to run , while old ones don't . Why is this so ? Are there few parts i can get from the electronics store to amplify those old speakers with soundmax m/b . ??


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## pradeep_chauhan (Feb 26, 2005)

If you have tinkered with electronics before I would suggest the LM 3886 audio amp. Ypu can download the data sheet from national semiconductors and make a 68W rms amplifire with JUST 4 additional components (excluding the speaker and the power supply) Its very easy and there are very few things that can go wrong as the IC has protection against all possible mistakes one can do.
Yes the older sound cards had small amps like LM386 (1-2W) built on but this trend has been discontinued possibly due to the scarce board space both on the mobo and the cards also the amps need some type of cooling and addl power supply these things are at a primeum on board. Also If a amp is provided then it ties down the user to use it thus limiting the sound card's employment and sound performance.


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## neerajvohra (Feb 26, 2005)

An incorrectly set up or unsuitable design of subwoofer can seriously compromise the accuracy of your monitoring environment. We outline the performance characteristics of the different types and show you how to incorporate a sub for optimum effect within your system.

Many people who have never actually worked with subwoofers say that it doesn't really matter where you put the sub, because low frequencies are omnidirectional. However, this statement is very misleading, because the physical placement of the subwoofer has a huge effect on its frequency response. Also, the interaction between the sub, satellites and listening room will cause peaks and troughs in the frequency and time domains, the effects
The closed-box speaker construction, with its typical frequency response.
of which are clearly audible. Can you tell if a speaker is wired out of phase within a few seconds of listening without having your head facing the speakers? Anyone who is 'tuned in' to phase anomalies will 'feel' the same effect from a badly placed sub in a good room.

In a multi-channel system there must obviously be a compromise. I would suggest that placement with the front speakers is favoured, as they carry the most important audio information and, once again, a centre position is ideal. However, experimentation shows that any frontal position is workable

Placement with respect to walls and other large structural features should be considered next. The majority of smaller subs will be designed so that they can be used out of the way against a wall. If such a unit is used freestanding, the frequency response and output level will suffer. On the other hand, a number of companies produce subs which are designed to be used freestanding and give best results when moved away from walls or other hard surfaces. The rule here is to check with the manufacturer and experiment with placement and/or listening position when performing the system setup.
When choosing a frontal position, care has to be taken if the sub is placed in a corner, as two problems arise. Firstly, corner placement will increase the low bass output of the sub and will often make it boomy. Secondly, using only one subwoofer will encourage the formation of standing waves in the room. This effect is exaggerated with a sub placed in only one corner. The effect of this can be heard as uneven bass throughout the listening room with some areas being boomy and some being bass light. It is possible to minimise this problem by using two subs, along with a shelving filter that curtails the rise in low end -- an approach I use in my own listening room.

Cant Give You Information better than that!!

Enjoy!!!!


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## klinux (Feb 26, 2005)

*www.crutchfieldadvisor.com/ISEO-rgbtcspd/learningcenter/home/speakers_placement.html

lots more online guides to speaker positioning . but in the end depends on persons interests in music and a bit of trial and error i guess .


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## Nemesis (Feb 27, 2005)

@neerajvohra: pls post the source and dont just baltantly plagiarize....


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## pimpom (Feb 27, 2005)

@klinux : The LM3886 mentioned by pradeep_chauhan is a nice IC. I have the data manual in CD and book form (sent to me by the manufacturers National Semiconductors) and I've used it a few times for purposes other than a computer sub-woofer. A practical design will yield something like 50W output instead of the theoretical 68W. Their LM12 is even more awesome. But there are practical factors you have to consider first.

For one thing, it needs a hefty power supply transformer able to supply more than 100W, at voltages that may not be available as standard (I make my own transformers). The IC also needs a huge heatsink.

And these are for a single-channel, single-IC amplifier. For a 5.1 system, you'll need four other amps. Even if you don't use an LM3886 for each amp, you'll need something that can keep the satellite speakers blaring at levels that can match the sub-woofer, let's say at least 30 *real* Watts each, not the inflated power ratings shamelessly quoted by manufacturers these days.

While I want to encourage everyone to get their hands dirty by practicing electronics, I suggest that those with limited experience try something less ambitious at first, such as the TDA 2000 series ICs.


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## klinux (Feb 27, 2005)

@pradeep / pimpom and all the other electronics guys : Why not make ur own sites with basics of electronics (indian version) or group together to bring out the best u guys have ??? . i checked up SISI has a few electronics courses , but not sure how useful . BSC electronics (corres) after an MCA sounds odd , but i think its worth it . I have a couple of friends who do electronic engineering projects here in chennai . i ask , they build lol . these guys started their own centre just after getting outta college . they focus mainly on java programming , cell phones , bluetooth and robotic projects . this is done just in weekends mind u . Hope u guys can form some sorta coalition in ur spare time . Thanx for all the info


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## pimpom (Feb 27, 2005)

klinux, this is not the first time you've asked me about my own website. I've never found time before, but you've really got me thinking now.

The thing is, IMO explaining the basics of electronics is more difficult than writing more advanced stuff for those who already know the basics well   I mean really explaining things so that anyone who's interested enough can get a firm grasp. Standard textbook approach is not suitable for that. Textbook presentations may be technically correct, but not at all suited for those who want or have to learn by themselves (as I did).

Mentioning technically correct but useless explanations reminds me of the helicopter joke about Micro$oft. If you haven't heard it, here's one source - *www.ajokes.com/jokes/1725.html

This joke is one of my favourites because it agrees exactly with what I used to think about MS help-files long before I heard the joke.


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## ctrl_alt_del (Feb 28, 2005)

Can anyone direct me to any website where I can find some help on making my own 5.1 speaker system? I have looked around and failed. If the site is an Indian one, its even better.


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## klinux (Feb 28, 2005)

@pimpom : true , i think last time it was regarding amiga . we used to have these books in school like 101 electronics experiments and stuff . a cool indi site with animation explaining stuff would be gr8 . I will try to get some basic info or easy info on electronics online . maybe a wiki might help too , with everyone puting in their info whenever possible . Will think abt it next weekend .
Addition : well if above is too hard , all might be able to put in their computer / computer accessory mods on here itself . funkymonkey had his rig up here , and i added one abt front panel audio . maybe that might be easier


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