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+4db, -10db...what does all this mean exactly?
Old 16th July 2017
  #121
Gear Head
 

Quote:
Originally Posted by Matt Syson View Post
Hi
I would be disappointed because getting from +4dB to -10dB simply requires 2 (or 3 if the circuit is balanced) resistors which cost a couple of cents each.
If you NEED an isolated signal then a transformer is the way to do it.
Unbalanced then you can use 3K Ohms and 1K Ohms to get the right amount of attenuation. If balanced then 2 pieces at 1K5 and one at 1K will do the job.
Matt S
Thanks. I added this clarification...

That is if you desire line isolation with the converter which makes this option worthwhile. I assume you're using AC power and may want to kill two birds with one stone and get rid of hum or reduce chances of hum. Most people I know of desire line isolation which is why I recommend this unit and why they make their converters with line isolation via transformer and don't make a stand-alone +4 to -10 converter without line isolation.

And, respectfully, my time is money. Many people, such as I, don't like making anything. Show me the right gear to buy and 9 times out of ten I can buy it cheaper than I can make it when you consider my hourly rate. Hence, you're not just buying parts...you have to count your time searching for and buying parts and learning how to make it, then time making it

Last edited by tayglo; 16th July 2017 at 09:55 PM.. Reason: added comment
Old 16th July 2017
  #122
Lives for gear
 

Hi
Correction to a previous post by Graywolf.
12dB is a ratio of approximately 4:1 not 2:1. Thus a 12 dB 'loss' is a quarter.

Tayglo, looks more like an advert than a clarification...
Matt S
Old 18th July 2017
  #123
Gear Head
 

Very happy to give them a thumbs up because they are the only game in town when it comes to a **passive** +4/-10 converter with or without line isolation unless you can show me another one. Trying to save others the hassle of finding a "passive" +4/-10 converter is not an advert it's a favor unless it's one of several, which, again, it's not to my knowledge. And, the fact that it's "passive" shows superior engineering so not hard to conclude the quality vs powered converters. My time is valuable and I wish someone would have pointed me towards this unit before spending my valuable time on Google searches. I thought GS was for helping others? And, even if it was a plug, which it was not, great equipment deserves recognition and that would have been OK too. Why? Because we need great gear!
Old 18th July 2017
  #124
Gear Nut
 
SF_Green's Avatar
Metric unit correction

Quote:
Originally Posted by Matt Syson View Post
Hi

M is Mega (million) an m is milli (thousand).

Matt S
Actually the milli is wrong. Milli is one-thousandth (so you're off by 1,000,000!)

Kilo = 1,000 X

Milli = 1/1,000 X
Old 18th July 2017
  #125
Lives for gear
 

I believe milli should start with a lower case m.
The RATIO is a thousand and being lower case means it is a thousandth.
Roughly the difference between a transformer in a box and a couple of resistors.
There are MANY transformer attenuators out there.
Matt S
Old 18th July 2017
  #126
Gear Nut
 
SF_Green's Avatar
Quote:
Originally Posted by Matt Syson View Post
I believe milli should start with a lower case m.
The RATIO is a thousand and being lower case means it is a thousandth.
Roughly the difference between a transformer in a box and a couple of resistors.
There are MANY transformer attenuators out there.
Matt S
Doesn't really matter when you spell it out: if it's the first word in a sentence you capitalize it, but you're correct as far as the abbreviation goes, for sure. Big difference between:

1 mV = 0.001 volts

1 MV = 1,000,000 volts

Actually, the prefix (milli, centi, Mega, micro, Kilo, femto, pico, Giga, Tera, atto) is a multiplier for the unit that follows. Sorry to Geek out on you, but I'm an analytical chemist and I use this stuff every day, so you've tickled my scientific funny bone.

Wiki:

A metric prefix is a unit prefix that precedes a basic unit of measure to indicate a multiple or fraction of the unit. Each prefix has a unique symbol that is prepended to the unit symbol. The prefix kilo-, for example, may be added to gram to indicate multiplication by one thousand: one kilogram is equal to one thousand grams. The prefix milli-, likewise, may be added to metre to indicate division by one thousand; one millimetre is equal to one thousandth of a metre.

Old 18th July 2017
  #127
Gear Maniac
 

Quote:
Originally Posted by Matt Syson View Post
Hi
Correction to a previous post by Graywolf.
12dB is a ratio of approximately 4:1 not 2:1. Thus a 12 dB 'loss' is a quarter.

Tayglo, looks more like an advert than a clarification...
Matt S
Grin!

We are dealing with voltage here not power. 20db volatage is 10:1, 10db power is 10:1. Actually, dB is a logarithmic power of 10 ratio. But it depends a lot on the units actually being measured and the point they are measured from

That is why 0dBFS, 0dBVU, 0dBu, 0dBV, 0dBw, etc. are all different values.

There is no doubt that it is confusing as hell, however.
Old 18th July 2017
  #128
Lives for gear
 
nosebleedaudio's Avatar
 

Quote:
Originally Posted by graywolf View Post
Grin!

We are dealing with voltage here not power. 20db volatage is 10:1, 10db power is 10:1. Actually, dB is a logarithmic power of 10 ratio. But it depends a lot on the units actually being measured and the point they are measured from

That is why 0dBFS, 0dBVU, 0dBu, 0dBV, 0dBw, etc. are all different values.

There is no doubt that it is confusing as hell, however.
Not really;
0dBVU can be what ever you want; -10dBV, +4dbm, 0dBV...
BUT what ever you choose a 3dB increase will result in twice the wattage (Power amp).
0dBV= 1Volt
0dBm= .775V
Like mentioned before...
Old 12th August 2017
  #129
Lives for gear
Well I'm glad this wasn't over-complicated.
Old 1st September 2017
  #130
Gear Head
 

Well, why don't we relax ourself here !
Old 20th January 2018
  #131
Old 27th January 2018
  #132
+4 dbu is 1.23 volts. -10 dbv is 310 mv. It is a 12.2 db difference.
Old 27th January 2018
  #133
Gear Guru
 

Yeah.... page one, post 2, 7 years ago.....

(damn I'm grouchy today....)

Last edited by mattiasnyc; 27th January 2018 at 10:06 PM.. Reason: Apparently it was answered 2 days sooner even.....
Old 27th January 2018
  #134
Gear Nut
 
SF_Green's Avatar
Quote:
Originally Posted by mattiasnyc View Post
Yeah.... page one, post 11, 7 years ago.....

(damn I'm grouchy today....)
Just switched to decaf?
Old 27th January 2018
  #135
Lives for gear
 
nosebleedaudio's Avatar
 

Quote:
Originally Posted by mattiasnyc View Post
Yeah.... page one, post 11, 7 years ago.....

(damn I'm grouchy today....)
36 thumbs up and so much is wrong...
Old 27th January 2018
  #136
Gear Guru
 

Quote:
Originally Posted by nosebleedaudio View Post
36 thumbs up and so much is wrong...
Ok, how about post #2 then? Was that correct?
Old 27th January 2018
  #137
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nosebleedaudio's Avatar
 

Quote:
Originally Posted by mattiasnyc View Post
Ok, how about post #2 then? Was that correct?
I answered it already in post #16 .
There is NO little v & big V.
0dBV =1V RMS
0dBu OR dBm Both are .775V RMS...
Old 27th January 2018
  #138
Gear Guru
 

Quote:
Originally Posted by nosebleedaudio View Post
I answered it already in post #16 .
There is NO little v & big V.
0dBV =1V RMS
0dBu OR dBm Both are .775V RMS...
Thant's not what I asked you. I asked you if post #2 was correct. Was it?

And is the difference between +4dBu and -10dBV 12.2dB?

But perhaps it makes sense to argue whether or not accurate information was given on the 3rd, 4th or 5th of January 2011?

I mean, is my point unclear here?
Old 27th January 2018
  #139
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nosebleedaudio's Avatar
 

Quote:
Originally Posted by mattiasnyc View Post
Thant's not what I asked you. I asked you if post #2 was correct. Was it?

And is the difference between +4dBu and -10dBV 12.2dB?

But perhaps it makes sense to argue whether or not accurate information was given on the 3rd, 4th or 5th of January 2011?

I mean, is my point unclear here?
More like 11.8dB difference.
Do the math; 1.23V/.310V the "dB" difference is 11.82dB...
Old 27th January 2018
  #140
Gear Guru
 

Quote:
Originally Posted by nosebleedaudio View Post
More like 11.8dB difference.
Do the math; 1.23V/.310V the "dB" difference is 11.82dB...
Ok, so the guy I was actually talking to had it wrong.

And both of the posts I pointed to, #11 and #2 were right.

What exactly is the problem here? (Other than this having been addressed over 7 years ago which has been my point all along)
Old 27th January 2018
  #141
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nosebleedaudio's Avatar
 

Quote:
Originally Posted by mattiasnyc View Post
Ok, so the guy I was actually talking to had it wrong.

And both of the posts I pointed to, #11 and #2 were right.

What exactly is the problem here? (Other than this having been addressed over 7 years ago which has been my point all along)
One of my issues is the v & V being different voltage, there is NO little v..
I think we have discussed this enough.
Old 27th January 2018
  #142
Gear Guru
 

Quote:
Originally Posted by nosebleedaudio View Post
One of my issues is the v & V being different voltage, there is NO little v..
I think we have discussed this enough.
Then why did you bring it up?
Old 27th January 2018
  #143
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nosebleedaudio's Avatar
 

Quote:
Originally Posted by mattiasnyc View Post
Then why did you bring it up?
Because it's wrong...
Old 27th January 2018
  #144
Gear Guru
 

Quote:
Originally Posted by nosebleedaudio View Post
Because it's wrong...
Is there anything else in the thread that wasn't discussed in the post I addressed that you also want to bring up because it was wrong?
Old 27th January 2018
  #145
Gear Guru
 

Incidentally, since you're such a stickler about this, mister sunshine actually said that the usage of "dBv" has been deprecated. Wikipedia says the same thing as do a bunch of other sources. So it seems you agree.
Old 27th January 2018
  #146
Lives for gear
 
nosebleedaudio's Avatar
 

Quote:
Originally Posted by mattiasnyc View Post
Incidentally, since you're such a stickler about this, mister sunshine actually said that the usage of "dBv" has been deprecated. Wikipedia says the same thing as do a bunch of other sources. So it seems you agree.
The books/manuals I read it from existed WAY before Wiki...
Won't bother next time..
Old 27th January 2018
  #147
Gear Guru
 

Quote:
Originally Posted by nosebleedaudio View Post
The books/manuals I read it from existed WAY before Wiki...
Won't bother next time..
So let me see if I get this straight;

I quote a guy and point out that what he's talking about was addressed 7 years ago.
You quote me and tell me the post I pointed to was wrong.
I ask if post #2 is correct.
You say the first post I pointed to was refuted by you.
I ask about post #2 again.
You start talking about "dBv" vs "dBV", which I didn't talk about, and neither the guy I first was talking to.
I ask why you're bringing that up, and you say it's because you're right.
I point out that you two are both agreeing that there's now only one usage of "dBV".
You claim that you're right anyway, despite you both ultimately saying the same thing.

And neither still addresses the guy I quoted here, or the fact that he was wrong... this year... instead of 7 years ago...

Did I get that right?

I don't think your I understand your priorities.
Old 27th January 2018
  #148
Lives for gear
 
nosebleedaudio's Avatar
 

Quote:
Originally Posted by mattiasnyc View Post
So let me see if I get this straight;

I quote a guy and point out that what he's talking about was addressed 7 years ago.
You quote me and tell me the post I pointed to was wrong.
I ask if post #2 is correct.
You say the first post I pointed to was refuted by you.
I ask about post #2 again.
You start talking about "dBv" vs "dBV", which I didn't talk about, and neither the guy I first was talking to.
I ask why you're bringing that up, and you say it's because you're right.
I point out that you two are both agreeing that there's now only one usage of "dBV".
You claim that you're right anyway, despite you both ultimately saying the same thing.

And neither still addresses the guy I quoted here, or the fact that he was wrong... this year... instead of 7 years ago...

Did I get that right?


I don't think your I understand your priorities.
I understand 100% of all this...
And YOU are misquoting me...
Enough about this, and YES IM a stickler..
If you are OK with Wrong incomplete info that's fine for you, Not for me..sorry...

Last edited by nosebleedaudio; 28th January 2018 at 11:25 AM..
Old 27th January 2018
  #149
Gear Guru
 

Quote:
Originally Posted by nosebleedaudio View Post
I understand 100% of all this...
And YOU are misquoting me...
Nope. I haven't misquoted you a single time.

Quote:
Originally Posted by nosebleedaudio View Post
Enough about this, and YES IM a stickler, Most great designers ARE...
And modest, it appears.

Quote:
Originally Posted by nosebleedaudio View Post
If you are OK with Wrong incomplete info that's fine for you, Not for me..sorry...
Is that why you corrected the person I was addressing? Oh, wait, you didn't. You corrected something posted 7 years ago.

Old 13th July 2018
  #150
Here for the gear
 

Hello everyone,

I've just read this thread and my head hurts trying to understand all this technical stuff.
I just need to know the right setting for my case, so I don't blow up my speakers, and I got really confused trying to figure the correct ones.

I've just bought a pair of jbl lsr305 monitors.
The default setting is -10db.
I've connected it using this cable:
Musician's Friend
(Only in my cable the red ones says "Ring" and the black ones says "Tip")
It's connected to the output of Creative soundblaster Z.

At -10db in the speakers The sound is really loud, to the point it even sounds compressed. even old low volume songs sound very punchy.
I've switched to +4db, and now it's not as loud. It's less punchy but sounds quite right.

Is it the correct setting? Does it endanger my speakers?

Thanks to every knowledgeable guy who can answer this for me.
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