?'s about xmax and power - Page 2 - Home Theater Forum and Systems - HomeTheaterShack.com

Old 01-22-12, 06:18 PM
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Re: ?'s about xmax and power

Quote:
GranteedEV wrote: View Post
two drivers in parallel will draw more power although not quite double. voltage "stays the same" but current will nearly double. Impedance is what would drop by half.

Of course ideally you would power each driver with its own amp channel. This lets each sub be set up individually based on its placement. For reference, two drivers, each fed 100W, will output the equivalent of one identical driver fed 400W, except with more ease as it isnt being run near its limits.

Right.

Wait, my knowledge of this is in the infancy stage. From what I've read, I don't quite agree with the last part of your post. Wouldn't two drivers fed 100W only gain 3db and the latter gain 6?

I was thinking it was the same as what you stated until a couple nights ago... then I got really confused with it all! lol
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Old 01-22-12, 06:38 PM
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Re: ?'s about xmax and power

Quote:
black_z wrote: View Post
Wait, my knowledge of this is in the infancy stage. From what I've read, I don't quite agree with the last part of your post. Wouldn't two drivers fed 100W only gain 3db and the latter 6db
two drivers simultaneously producing the same output, colocated (IE 90db @ 100W each) will result in a net 6db gain (IE 96db)

Now if two drivers in series and colocated, amp power will be divided between them. each driver in series off a single 100w amp will only get 50w as less current will run through them. So those 90db @ 100w drivers will only output 87db each @ 50w for a total of 93db (6db gain). Net gain is.therefore 3db. However some amps can deliver more voltage into IE 8 ohms than they deliver into 4 ohms so results will be better than the theory suggests.

In parallel off one amp, max output will depend on the amp's behaviour into low impedance loads. Most amps deliver less voltage driving a 2 ohm load than a 4 ohm load, so you won't get the full 6db gain and the excess current will increase amp heat.

Not colocated all bets are off but response will be overall smoother and you will still get some summation.

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Old 01-24-12, 09:20 PM
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Bubba

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Re: ?'s about xmax and power

Ok... I think the websites I found showing a 3db gain when doubling equal sources were referring to Sound POWER Lever, instead of Sound Pressure Level. There was some pretty involved math explaining it, but I'm just hoping it was talking about the power level versus pressure level.
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Old 01-24-12, 09:46 PM
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Re: ?'s about xmax and power

Here is one of them... http://www.sengpielaudio.com/calculator-spl.htm

It's sorta confusing. The calculators do seem to be talking about pressure, but give 3db as an answer. Although if you look closely at the chart around halfway down the page, you can see where it says 6db for pressure and 3db for intensity.
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Old 01-25-12, 02:42 AM
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Re: ?'s about xmax and power

Quote:
black_z wrote: View Post
Here is one of them... http://www.sengpielaudio.com/calculator-spl.htm

It's sorta confusing. The calculators do seem to be talking about pressure, but give 3db as an answer. Although if you look closely at the chart around halfway down the page, you can see where it says 6db for pressure and 3db for intensity.
Here is the key quote:

Quote:
Provided, that each sound source has its own random phasing
Colocated Subwoofers covering the bass band, in phase, are going to sum up in phase. This is different from, say, colocated tweeters above 10khz.

Don't underestimate us! Whether it be time, space, or alternate realities, they mean nothing to us! We will pierce the path and methods you've chosen! That is who we are!
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Old 01-25-12, 10:59 AM
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Bubba

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Re: ?'s about xmax and power

I see so many conflicting articles on the internet it ain't funny!

I'm gonna have to experiment and see what I find out for myself!
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