6.5"-7" sub comparison
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From: Champaign/Chicagoland
Originally Posted by dragonrage
Don't go by published sensitivity ratings, use Thiele-small simulations or measurements (best, of course, but I'm not buying and measuring all of these in my car... sorry). And it actually takes 10dB to double the volume (3dB is double the power, but our hearing is logarithmic), but 3dB is still somewhat significant, and 5dB is still a big difference.
Put it this way: Extremis for SPL, ED or Mpyre for quality.
Put it this way: Extremis for SPL, ED or Mpyre for quality.
EDIT: Nevermind, I've convinced myself that (a) is the same thing that you said.
Last edited by fredmr39; Feb 6, 2007 at 01:22 AM.
Launching!
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Originally Posted by fredmr39
Sorry - (a) a speaker 3 dB more efficient than another demands HALF as much power from your amp to REACH the same volume. That is how I MEANT to say it....but I still don't think we are agreeing. Anyways yes....I think we agree that 3 dB is double, and that we just don't perceive it as that...
EDIT: Nevermind, I've convinced myself that (a) is the same thing that you said.
EDIT: Nevermind, I've convinced myself that (a) is the same thing that you said.
a speaker 3 dB more efficient than another demands HALF as much power
>>>
"demands"
intresting....hmmm
I guess that would depend on the amp and the load it seeks...to make said counterpart worthy? TECH Fanatic
Joined: Oct 2006
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From: Champaign/Chicagoland
Originally Posted by B T
>>>
a speaker 3 dB more efficient than another demands HALF as much power
>>>
"demands"
intresting....hmmm I guess that would depend on the amp and the load it seeks...to make said counterpart worthy?
a speaker 3 dB more efficient than another demands HALF as much power
>>>
"demands"
intresting....hmmm
I guess that would depend on the amp and the load it seeks...to make said counterpart worthy? Launching!
Joined: Jul 2004
Posts: 291
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Originally Posted by fredmr39
Yes...demands. That is why running the factory amp into 1 ohm impedances isn't a good idea. Non-technical response: The amp will try to produce the "power" demanded, regardless of stability/limitations. It reminds me of a goldfish...keep giving it food and it'll keep eating until it dies - doesn't know it's limitations......................eh.....kinda
Kinda funny, you would have to mention fish.
I'll try not to feed them too much mojo.
I think so far as I can tell it will be very fine.
Futher testing/daily usage will finally tell the tale, ( i can't wait to flog it hard ) and see what coughs up first.
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From: Jacksonville, FL (originally from Toronto Canada)
Originally Posted by fredmr39
Sorry - (a) a speaker 3 dB more efficient than another demands HALF as much power from your amp to REACH the same volume. That is how I MEANT to say it....but I still don't think we are agreeing. Anyways yes....I think we agree that 3 dB is double, and that we just don't perceive it as that...
EDIT: Nevermind, I've convinced myself that (a) is the same thing that you said.
EDIT: Nevermind, I've convinced myself that (a) is the same thing that you said.
Or maybe it's years of marriage - as time goes on I get better at tuning out "she who must be obeyed" so she has to use more volume. 
In any case, I think you may have misconstrued a prior comment I made about how inefficient the factory speakers are and how a difference of only 3dB more sensitivity will normally make up for the volume loss from increased impedance. This was stated from experience, not mathematics. There are other things besides sensitivity and impedance that influence the apparent volume of any given set of speakers and I've found that aftermarket replacements generally don't suffer much (if any) volume loss for being 4-ohm instead of 2-ohm. Unfortunately I don't have any sensitivity specs for the factory speakers so it's all guesswork.
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Originally Posted by melchoir
Does anyone have any real numbers on what our stock amp pushes to the sail panels RMS anyway?
I found this in the FAQ posted by whitebird00:
The amp is a small eight-channel unit mounted on a bracket on the right quarter inner fenderwell (hatch area of a coupe, trunk of a convertible). It powers a mix of 2-ohm and 4-ohm speakers. The 97 and some early 98 models came with a 200 watt amp that was physically smaller than later models. The rest of 98 through 99 came with an amp that was rated at 200-watts RMS. For 2000 and later models, GM changed their advertising to rate the very same amp at 500-watts. Some say this is a peak rating while others just consider it an ILS (If Lightning Strikes) rating. GM also claimed an RMS rating of 240-watts for this amp but the original 200-watt rating given to the amp is probably more accurate. In any case, there is no point is trying to upgrade a 98 or 99 to the "more powerful" 500-watt amp of later years - it's exactly the same amp.
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From: Champaign/Chicagoland
(a) A speaker 3 dB more efficient than another demands HALF the power from your amp for the same volume.
(b) If a sound gets louder by 3 dB it is only a little louder, but takes double the power from your amp to produce a noticeable increase in volume. (and as mentioned 6-10 dB to sound double the volume.....with 10 dB requiring TEN times the power).
---
I have always had those two ideas in my head...I know (b) is true, and is not saying the same thing as (a)...but for some reason...I had always thought that (a) was true too...
EDIT: I Googled (a), and found the following - figures it does come from the BestBuy link though:
"...a speaker that's a mere 3 dB more efficient than another demands only half as much power from your amp to reach the same volume. A speaker that's 6 dB more sensitive needs only a quarter as much power!"
(b) If a sound gets louder by 3 dB it is only a little louder, but takes double the power from your amp to produce a noticeable increase in volume. (and as mentioned 6-10 dB to sound double the volume.....with 10 dB requiring TEN times the power).
---
I have always had those two ideas in my head...I know (b) is true, and is not saying the same thing as (a)...but for some reason...I had always thought that (a) was true too...
EDIT: I Googled (a), and found the following - figures it does come from the BestBuy link though:
"...a speaker that's a mere 3 dB more efficient than another demands only half as much power from your amp to reach the same volume. A speaker that's 6 dB more sensitive needs only a quarter as much power!"
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From: Champaign/Chicagoland
Originally Posted by melchoir
That shows an "overall" power rating, but I was looking for how much power actually gets sent to the sailpanel speakers.
Joined: Nov 2003
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From: Jacksonville, FL (originally from Toronto Canada)
One decibel is the smallest amount of change in volume that the average human ear can differentiate (again, it probably takes more than that for an old fart like me). It takes twice as much power to produce a three decibel increase in volume which is preceived by the human ear as being about a 25% louder (actually 23 point something percent, but who's counting). Then it takes ten times as much power to produce a 10dB increase which is perceived as double the volume. Isn't mathematics fun?
Using JL 6-1/2" w0's in the rear seat speaker locations sounds great! I've got them playing free air with the rear quarter panels heavily sound deadened. They're being powered with approx 75wrms with a directed amp though. You get about the output of a decent 10" in the hatch with the set up I'm running, however, the kickbass in rock in simply amazing!
