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Old 20th November 2011, 02:14 PM   #11
sreten is offline sreten  United Kingdom
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Quote:
Originally Posted by Saturnus View Post
lol. You can't be serious.

Ok. Let me spell it out so even you can understand it.

For the Monacor SP-60/4

90 dB @ 1W
93 dB @ 2W
96 dB @ 4W
99 dB @ 8W
102 dB @ 16W

For the VIFA coax

87 @ 1W
90 @ 2W
93 @ 4W
96 @ 8W
Hi,

Of course I'm serious, the above attitude is childish IMO.

What is the difference between sensitivity and efficiency ?

The Monacors senstivity is incorrectly given, as usual as 90dB/W.
What it really means is 90dB for 2.83V *, for a 4ohm driver this
means its actually 87dB/W efficiency, as nominally 2.83V is 2W.

Happens all the time with people misunderstanding 4ohm sensitivity.

Sensitivity and efficiency are "equivalent" for an 8 ohm driver,
its OK to use /W instead of 2.83V. For a 4 ohm driver they are
not but the misleading practice persists, its a better number.

For sensitivity you have to understand a 4ohm W is actually 2W.

For a 16 ohm driver sensitivity is 3dB less than efficiency,
for a 4 ohm driver its 3dB more, for a 2 ohm driver +6dB.

rgds, sreten.

* Senstivity is always measured with a voltage that = 1W for 8R at 1m.
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Last edited by sreten; 20th November 2011 at 02:41 PM.
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Old 20th November 2011, 07:32 PM   #12
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Quote:
Originally Posted by sreten View Post
The Monacors senstivity is incorrectly given, as usual as 90dB/W.
What it really means is 90dB for 2.83V *, for a 4ohm driver this
means its actually 87dB/W efficiency, as nominally 2.83V is 2W.
No, it's not incorrectly given

Both the 4 ohm and 8 ohm version has a 90 dB/w/m specification. As with all serious manufacturers of speakers, sensitivity is measured at 1W into the actual impedance of the driver.

So the 4 ohms version would actually be 93 dB/2.83V/m.

It is your assumption that the specification is incorrect that is wrong.
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Old 21st November 2011, 02:34 PM   #13
sreten is offline sreten  United Kingdom
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Quote:
Originally Posted by Saturnus View Post

Sensitivity is measured at 1W into the actual impedance of the driver.
Hi,

No its not, ever. Its for 2.83Vrms at 1m into 2pi (halfspace loading).

Sensitivity always relates to the level for a given voltage input,
and so do all the response graphs, no other way of doing it.

Your making up stuff to defend an untenable position,
and ignoring the way it actually is, for no real purpose.

Here is an honest spec :
Dayton Audio DCS205-4 8" Classic Subwoofer 4 Ohm 295-200

Quote:
• SPL: 87 dB 2.83V/1m •
As its a 4 ohm driver that is 87dB per 2W not 1W.

rgds, sreten.
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Last edited by sreten; 21st November 2011 at 02:37 PM.
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Old 21st November 2011, 02:36 PM   #14
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Old 21st November 2011, 03:44 PM   #15
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Quote:
Originally Posted by sreten View Post
Hi,

No its not, ever. Its for 2.83Vrms at 1m into 2pi (halfspace loading).
Are you an idiot? Or just trying hard to be. Have you ever worked in the industry at all? Doubtful to say the least.

Here's a trustworthy specification sheet. Not the Dayton crap you posted.

http://www.eminence.com/pdf/Beta_10A.pdf

See note ***. Every respectable manufacturer lists sensitivity like that, ie. 1W into the nominal impendance, or specifies 2.83V for voltage sensitivity but that gives a distorted picture when you manufacture the same driver with different impendances.

Fact is, The Monacor SP-60/8 - the 8 ohms version specifies 90dB/W/m, and so does the 4 ohms version. That's because both drivers are identical except for the impedance, even an idiot will realize this. The magnet strength is the same, the cone weight is the same, and therefore they both output the same at 1W power input.

Now stop you mindless ranting and realize that you made a mistake (you don't even have to admit, I really don't care either way) and be done with it.

Last edited by Saturnus; 21st November 2011 at 03:50 PM.
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Old 21st November 2011, 09:46 PM   #16
sreten is offline sreten  United Kingdom
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Quote:
Originally Posted by Saturnus View Post

Are you an idiot? Or just trying hard to be.
Hi,

No. You seem to be and doing it very easily.

If you don't know what I'm talking about, you don't know much.

Referencing professional driver specs is irrelevant for hifi driver specs,
its different and I do know about it, but here it is not relevant.

I know my stuff, I know what I'm talking about, and what I've said is very reasonable.

You can't see the monacor specs are totally inconsistent, and therefore
not to be trusted in the first place, no way will a 4 and 8 ohm version
of the same driver have the same specs, they simply don't.

You can't base any argument on stupid incorrect published numbers.

I'm fed up with being insulted by the clueless, your saying the wrong things.

rgds, sreten.
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Last edited by sreten; 21st November 2011 at 10:08 PM.
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Old 22nd November 2011, 05:26 AM   #17
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Quote:
Originally Posted by sreten View Post
I know my stuff, I know what I'm talking about, and what I've said is very reasonable.
Sadly you don't. You see. I have had about 20 of these Monacors past my test bench, and they measure as I describe above. Naturally not as linear as Monacor's own specs but pretty near. Slightly higher average sensitivity than Monacors measurements. They average 90dB at 2V (not 2.83V). And that is that. End of story. Goodbye.
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Old 22nd November 2011, 12:08 PM   #18
sreten is offline sreten  United Kingdom
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Hmmm......

A lot of posturing for a simple technical point that is generally true and quite
reasonable to suggest, even if its not apparently specifically true in this case.

rgds, sreten.
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Old 25th November 2011, 04:10 AM   #19
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Not sure I want to wade into this one, but 2.83V into 4 ohms is most definitely 2 watts.
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Old 25th November 2011, 05:40 AM   #20
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If it is listed as 1 watt into then it is 1 watt no matter what the impedance is as it is 1 watt into that load.

If it is 2.83 volts then that equates to 1 watt into 8 ohms, 2 watts into 4 ohms, 0.5 watts into 16 ohms, 4 watts into 2 ohms, etc...

It depends on how the spec is written, then that determines how it was tested and at what distance to measure dB level for sensitivity.
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