Rule of thumb for subwoofer size ?

[BackBurner]

Is there some published information or rule of thumb for the size , number of or placement of subwoofer / subwoofers per your room size ?

My question is more regaurding home theater use. I just want to find out how you know when enough sub is enough sub .

[InnovaZero]

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On 3/14/2004 3:46:14 PM BackBurner wrote:

I just want to find out how you know when enough sub is enough sub .

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For TheEar, a resident of these forums....there is never enough sub-sonic action.

[ccsakura]

Lol.......... depends on how much you love the bass volume would be. Some like earthshaking even listening to music or watching dramas, some don't. Some just want to have certain bass to match the rest of the system. It is all depend your preferences .

[TheEAR]

When the subwoofer(s) satisfies your craving for deep bass at the highest volume you will ever listen to.

Me,when at 1/4 of the max output my ears give up

And to answer "Is there some published information or rule of thumb for the size"

NO there is none as some compact subs outperform larger ones BIG time,sometimes.And listening preferences varry too much.

[BackBurner]

I find this lack of information hard to believe.

What you guys are saying is it's up to you to decide ??

OK i've got a room thats 100ft x 100ft so if i think one tiny 12 inch sub is enough then i'm right ???

Ok i've got a room thats 24ft x 20 ft and i fill it with 25, 18 inch 6000watt subs , i'm right again ???

There has to be some sort of THX rating or method of calculating room size to sub woofer output. It can't be as simple as how much bass do you like , a single subwoofer has to have an effective area it's able to produce bass at a certain level.

I'll try the guys over at AVS , i'm sure they will know.

[hooting_monkey]

Dude, you dont understand. You could be in an infanately large room and a ProMedia sub can be more than enough. It depends on how close you are to the sub, how much bass you like, and the geometry of the room. There are millions apon millions of variables to consider. Do you have a rule of thumb on how to predict weather for the next 100 years? It's the same kind of question...

[BackBurner]

Ok lets take this from another angle.

Your building a 400 seat theater thats 350 ft long and 150 ft wide how do you figure out a subwoofer combination thats going to give you proper SPL over the entire space.

Don't even bother telling me it's trial and error !

[T_Shomaker]

For that you would need a whole bunch of 18" cinema subs and some pretty powerful amps.

[ccsakura]

Whoa cool down guys...... some people like to be guided all the time and believe in common folks' comments other than their on ears...... vice versa.... let it be

This is also matters of personal preferences and taste, we can't intrude others' taste(as they can't either unless you want them to). Like no one ever complains TheEar has too many subs in his house and you need some handrail to walk into his house, he can't complain you have not enough bass subs to shake in your house either .

At least I like to have bass but not keeps staring my ceiling to fall down anytime or my landlord goes upstairs and kick me out from the window directly . If I have my own house I may do that

[BackBurner]

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On 3/15/2004 11:00:05 PM T_Shomaker wrote:

For that you would need a whole bunch of 18" cinema subs and some pretty powerful amps.

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Now your finally starting to see what i asked from the start .

Ok then , how many 18 inch subs ? how big of amp ?

Thats all i'm after , some kind of guideline or formula for figuring out total space and or area to be cover'ed. It can't be a total guessing game , there has to be a formula or guideline used by the pro's.

like : 1 18 inch sub at 800 watts will cover x amount of cubic space to y amount of spl . So if your total cubic space is ____ then you will need ____ subwoofers at z amount of watts to reach _______ spl in that space.

[hooting_monkey]

But, then for that to work you can only talk about a specific line of speakers, as quality of parts is as importaint as the size. An 18" car sub would cry mercy to a 10" HT sub.

[hooting_monkey]

Also, when you wanna know if a sub is too big. If it's becomming uncomfortable to listen to and isn't faithful to what the real song sounds like, it's either too big or small. I suppose for a room 12'x12' a 10 incher is more than enough. (12 incher if you're a rap addict.) 12 inchers til 15' x 15'. 15 inches on anything bigger.

[T_Shomaker]

Well my stepdad uses one of those 18" subs in his HT and it seems to be perfect for the system! It is powered by a bridged Yamaha M-40 amp. It sounds really good and isn't boomy. I am guessing you would need at least 3 of these subs for a theatre (I have no clue). I don't really know any kind of formula to find the perfect size sub for a room. I don't think one of those would be possible to make because everybody has their own opinion on how big of a sub you would need. For example TheEar has about five times as many subs as any other person would use. Why don't you tell us what kind of room you need a sub for and what you are using it for. If you did that we would be able to make a guess on what you would need.

[TheEAR]

BackBurner,

How large is your room(including height),number of seats.I will answer based on the 31.5Hz point and 110dB sustained level at listening position.

So throw the numbers now(room size)

[CAS]

The Ears will probably give you a ballpark, but you have to understand that it really (REALLY) is not that simple.

It has to do with enclosure size, design, amp size, quality, material, frequency response, equalization, room dimensions, dynamics, placement, listening position, port length, port size, interior wall materials, and a hundred other factors I can't even thing of. A given amp/speaker size/brand could give you anywhere from a mild dose of low frequencies to earth shaking. The same goes for huge subs. Would a radio shack 10 in sub with a 1500 watt amp (and a very large enclosure) give the same bass as a sunfire 10 with the same amp (and the smallest enclosure you can find)? In this case it's completely counter-intuitive.

It's a very unique question who's only detailed answer can be reached by research and trial.

After all: Why do you think there are hundreds of powered subwoofer discussion boards on the net?

[ygmn]

You could any decent sub..and add some bass shakers to the seats.....this gives the effect of a large sub...cause your butt shakes from them depth charge scenes in U-571....hehehe

If there was a formula....there would also be a formulas on what speakers to have as mains and center etc etc etc...and only a few speaker manufacture all making the same thing but in different colors....

I do understand your question though....How do I know which SUB to buy for my room? Bigger is mostly always better.....

compare the specs on subs...what ya want is to hit 85 dB with a test disk for HT so that in the loudest points you hit the desired 115 dB as the movie director desires....

Good luck....

[BackBurner]

EAR : THANKS

The room is 24 x 20 with a 10 ft ceiling , this is a basement project. This room has 4 concrete walls , no windows and a 4ft x 7ft entrance .

10 Screen on the front wall ( the 20 ft wall ) 8" crt front projector.

Mains are 89 khorns , center is a 94 belle , rear are 86 lascala's

Right now i've got a klipsch ksw-300 and a ksw-15 . Not 100% sure if the model # are correct but 1 is a 300 watt the other is a 800 watt , both are klipsch.

The walls are being constructed useing the ISO wall system (over 2x6 insulated walls )which is 2 layers of drywall with vibration padding between layers, same thing on the ceiling . They have a web site if you guys want more info than that.

This room is being built just like a studio , if specs are maintained then bass response should be increbile .

I was looking at going with some sort of SVS tube style dual subwoofers as i don't believe the subs i have now were made during klipsch finest hour.

[Colin]

Objectively, the amount of sub-woofer support you need is enough to balance out the entire frequency response range of your home movie and music reproduction system, down to 20Hz, and within 3dB. For that you need a Test CD and a Radio Shack SPL meter (they are little and cute now). The reality however, is that most people, myself included, listen to way too much bass, especially for movies.

The other rule of thumb is to spend as much on the powered sub-woofer as you spent on the main loudspeakers or the front-end equipment.

[TheEAR]

"The room is 24 x 20 with a 10 ft ceiling , this is a basement project. This room has 4 concrete walls , no windows and a 4ft x 7ft entrance .

10 Screen on the front wall ( the 20 ft wall ) 8" crt front projector.

Mains are 89 khorns , center is a 94 belle , rear are 86 lascala's"

Well first you have a huge room considering how high it is.Four concrete walls are great news,the bass pressure will work in the room,not flex paper walls for nothing.

Your mains are very capable and can generate way over reference level loudness at sitting position.All large and capable speakers,even as sourrounds.

This calls for the following options(unless you like unbalanced systems)...

a) one SVS B4-Plus/Crown K2 this is a ONE subs does it all solution

dual SVS Ultra be it passive or powered set in one corner or along side the front wall,should be just ok

c) dual Klipsch RSW15 if you would like have Klipsch all around(stacked in a corner)

d) one Revel B15 sub in a corner

e) one SVS PB2-Ultra sub,in a corner(could do the trick)

If I had a room as large as yours I would go right away with at least a B4-Plus/K2 combo,no fooling around here.A puny joke like KSW makes it all feel like a cheap tweeter is buzzing,at least dual RSW15's(and the RSW15 brutalises any previous Klipsch home sub on deep bass)

[BackBurner]

Thank again ear

I'll lean towards the B-4 plus and let you know how it works in this room.