how can calculate SPL and power at subwoofers ? - AVS Forum
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Old 02-08-2014, 12:37 PM - Thread Starter
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spl and acustic output is not same ?  and which subwoofer is more spl more pressure in the room ? whish is more strong ?
is the jamo says 1 watt 1 meter 109 db spl ? 400 watt 125 db from 3 meter spl ?
i found the web site for calculate but dont understand
http://www.sengpielaudio.com/calculator-efficiency.htm


 

 

 

 

Frequency Response: 18Hz-150Hz ± 3dB
MAX ACOUSTIC OUTPUT: 121dB @ 30Hz 1/8 space, 1m
AMPLIFIER TYPE: BASH® Digital Hybrid
AMPLIFIER POWER: 400 watts continuous @ <2% THD / Dynamic Power*: 800 watts
DRIVE COMPONENTS:

15" (38.1cm) Active non-resonant Woven Fiberglass driver


 

 

 

 

this is klipsch sw 115

 

Frequency Response (Hz, +/-3dB)    20 200
Power Handling (Watts Long/Short Term)    800Wrms@4O/1600Wpk@4O
Rated output (W)    600Wrms@4O@THD+N <1%
Sensitivity (dB, 2.8V/1m)    109 dB

and this is jamo d600 thx sub

 

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Old 02-08-2014, 12:47 PM
 
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"1 watt 1 meter 109 db spl"

Is the efficiency or sensitivity of the subwoofer. This allows one to compare dissimilar subwoofers.

"125 db from 3 meter spl"

That's an "anechoic" measurement so an individual can compare dissimilar products when in use.

What is it you're trying to figure out?

(SW-115 Subwoofer)
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Old 02-08-2014, 03:16 PM - Thread Starter
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i think klipsch 121 db is not sensitivity  its maximum output and calculators  not find same values in that web site when calculating  electro acoustic output  and spl calculating ..  i think an electronic enginier can help ..   what is   acuostic db and spl db different ?  and how can i calculate klipsch sw 115 1m 1 watt 2.8V  sensitivity .. 121 db is not sensitivity i think ..   i want to compare   spl or acoustic values but  i see klipsch's acoustic value and jamo's spl value ..

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Old 02-08-2014, 03:48 PM
 
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The 121dB is the max output according to "Anechoic Chamber" measurements. The 109dB is the sensitivity output rating. I don't know what the sensitivity rating for the SW-115 is.
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Old 02-09-2014, 09:15 AM
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sensitivity is measured at one watt input. Or at least at the voltage that yields one watt with an 8 ohm load (meaning that for a 4 ohm speaker it's really 2 watts). So 109 dB with one watt. But the speaker can take more than one watt of input, and more input means more output. The 121 dB is probably simply calculated from max power handling (add 3 dB for every doubling of power - - so 112 dB at 2 watts, 115 dB at 4 watts, etc.)

Sadly, real world speakers start to compress (not get as much louder as the increased input calls for) typically somewhere around half their rated power handling capability, but this is highly frequency dependent. In the end, however, it means you're not likely to really get 121 dB at 40 Hz, for example, with full rated input power . .
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Old 02-09-2014, 10:38 AM
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Quote:
Originally Posted by denizcell View Post

spl and acustic output is not same ?  and which subwoofer is more spl more pressure in the room ? whish is more strong ?

is the jamo says 1 watt 1 meter 109 db spl ? 400 watt 125 db from 3 meter spl ?

i found the web site for calculate but dont understand
http://www.sengpielaudio.com/calculator-efficiency.htm
Frequency Response: 18Hz-150Hz ± 3dB
MAX ACOUSTIC OUTPUT: 121dB @ 30Hz 1/8 space, 1m
AMPLIFIER TYPE: BASH® Digital Hybrid
AMPLIFIER POWER: 400 watts continuous @ <2% THD / Dynamic Power*: 800 watts
DRIVE COMPONENTS: 15" (38.1cm) Active non-resonant Woven Fiberglass driver


 


this is klipsch sw 115
Frequency Response (Hz, +/-3dB)    20 200
Power Handling (Watts Long/Short Term)    800Wrms@4O/1600Wpk@4O
Rated output (W)    600Wrms@4O@THD+N <1%
Sensitivity (dB, 2.8V/1m)    109 dB
and this is jamo d600 thx sub


 

If you are stuck between these two subs; simply know that SW115 does not justify $800 price tag. Jamo D600 is a far superior sub between the two. Forget about sensitivity. Klipsch specs are corner loaded in-room stats @ 1 meter, which look impressive to the naive eye.

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Old 02-09-2014, 10:48 AM
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Originally Posted by braveheart123 View Post

If you are stuck between these two subs; simply know that SW115 does not justify $800 price tag. Jamo D600 is a far superior sub between the two. Forget about sensitivity. Klipsch specs are corner loaded in-room stats @ 1 meter, which look impressive to the naive eye.

Agreed.

If you have subs you are considering, you can simply ask which is better here, rather than trying to figure it out based on manufacturer specs, which are often unreliable. smile.gif

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Old 02-09-2014, 11:00 AM - Thread Starter
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i know of course d600 better .. i only want to learn how can i understand which subwoofer is more earthquake ... which is more pressure 20 30 40 hertz maximum sound ..  now i have jamo sub 360 its not mine only using it until my d600 subwoofer come to turkey .. but jamo d360 power is very very small for me ... i want to buy subwoofer for 20 30 hertz maximum db and maximum cleanly  i dont think to buy Klipsch sw 115 only sample ..  two sub 400 watt continuous amplifer and  38 cm   i want to learn calculating subwoofer maximum 20 and 30 hertz power %1 thd

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Old 02-09-2014, 11:08 AM - Thread Starter
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 20 30 40 hertz performance compare or all hertz 10 200 hertz  compare how can calculate.
1. rule 20 hertz or 30 or 40
2. rule %1 thd maximum
question which is  maximum power pressure and db ? ( not for sw 115 ... for all how can calculate )
I want to fell the pressure and sub bas bang in my chest.

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Old 02-09-2014, 11:12 AM
 
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Start at Data-Bass and look at their spreadsheet.

Then check out the first couple of posts in the ULF thread and you'll get an excellent idea how well different subwoofers perform in different venues.

Around these here parts, there's the budget minded subwoofer threads with lots of excellent user/test performance data.

The main subwoofer manufactures that get the most forum love are:

Hsu

SVS

PSA

Rythmik

That's not a knock on any of the other manufactures and there's always the wonderful world of (DIY) do-it-yourself. Lots of good information to be found in the DIY forum.

Hope the above helps give you the information you're seeking.
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Old 02-09-2014, 11:13 AM
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Well, then in answer to your title "how can calculate SPL and power at subwoofers," it really can't be done from manufacturer specs because of some combination (or all) of

(a) they don't provide enough information
(b) they all measure things differently
(c) their specs are purposely misleading or inaccurate.

You really need independent measurements in most cases to know with any certainty.

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Old 02-09-2014, 11:13 AM
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i want to learn calculating subwoofer maximum 20 and 30 hertz power %1 thd

Lower your expectations; they are very far fetched. As regards SPL, it's all relative to the listening area and how far you are from the sub. Anyway, reduce 6dB for every meter added to the 1w/1m rating and you will get the required spl at your main listening position for that 1 watt.

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Old 02-09-2014, 11:16 AM
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I've had SW115 in the past and sold it just after a couple of weeks. The amp on that sub is very weak and specs are plain rubbish. Though it does get down to 18Hz. But who knows at what level of THD?

History is written by those who have hanged heroes ...

The best EQ is no EQ ...

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Old 02-09-2014, 11:17 AM
 
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Quote:
Originally Posted by braveheart123 View Post

Lower your expectations; they are very far fetched. As regards SPL, it's all relative to the listening area and how far you are from the sub. Anyway, reduce 6dB for every meter added to the 1w/1m rating and you will get the required spl at your main listening position for that 1 watt.

Not arguing, I thought is was; reduce 6dB for every doubling of distance: 1m > 2m > 4m. Or a 12dB loss if going from 1m > 4m.
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Old 02-09-2014, 11:18 AM
 
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Quote:
Originally Posted by braveheart123 View Post

I've had SW115 in the past and sold it just after a couple of weeks. The amp on that sub is very weak and specs are plain rubbish. Though it does get down to 18Hz. But who knows at what level of THD?

...^ +1

Klipsch, if you like horns, great speakers but if you like subwoofers, sucky subwoofers.
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Old 02-09-2014, 11:20 AM
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Not arguing, I thought is was; reduce 6dB for every doubling of distance: 1m > 2m > 4m. Or a 12dB loss if going from 1m > 4m.

Yes I guess you are right. Um getting rusty here biggrin.gif

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Old 02-09-2014, 11:28 AM
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Not arguing, I thought is was; reduce 6dB for every doubling of distance: 1m > 2m > 4m. Or a 12dB loss if going from 1m > 4m.

While that’s true, when comparing numbers everything else has to be consistent. One can’t take for granted that’s the case in many instances. 1m versus 2b wont necessarily give you the whole picture. Another little lesson I learned the hard way rolleyes.gif

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Old 02-09-2014, 11:29 AM - Thread Starter
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Old 02-09-2014, 11:30 AM
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Originally Posted by braveheart123 View Post

Yes I guess you are right. Um getting rusty here biggrin.gif
The inverse square rule only applies outdoors. Indoors room modes contribute so much to the final result that it's incalculable, though a rule of thumb of a 3dB loss per doubling of distance is as good as any in determining your speaker needs.

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Old 02-09-2014, 11:33 AM
 
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Originally Posted by steve nn View Post

While that’s true, when comparing numbers everything else has to be consistent. One can’t take for granted that’s the case in many instances. 1m versus 2b wont necessarily give you the whole picture. Another little lesson I learned the hard way rolleyes.gif

Fortunately, since we all live in a perfect world, we don't have to deal with these inconveniences. tongue.gif
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Old 02-09-2014, 11:35 AM
 
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Thank you realy but i cant buy

My understanding, SVS can be found close by as they have some European distributorships. I apologize that I can't give you better information.
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