fiQ15 question

[dman4486 5,000+ posts]

Thermally, do you guys think a Q15 can take 2kw?

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[hornedfrog1985 5,000+ posts]

no

 

[Kyle_Keating 10+ year member]

once in awhile i do this because i hate stupid questions.

power is not *that* important for subs (it is, but not to the exact people ask about it), i mean even if you buy a 2k amp and you're pulling 2k from it at one point, that’s only going to be one frequency on your system and on average, even at max output, your amp is going to do fall less than 2k unless you're running pure sinwave to it during a test. Most of these switching amps cant even do their RMS for very long so, if you put a linear amplifier at 2k and hooked it up to a sub and pulled 2k from it, i'm sure you will kill any driver under the sun with enough time.

most of the time you DONT run it at max and most of the time you DONT run a sinewave at an impedance minimum, on average subwoofers see FAR less power than you would ever expect.

found that pic on goolge.... looks like a 4th order vented box for an 4 ohm vc....(not for car audio) its only at 4ohms at 25Hz it would normally be filtered below that so it wont reach much below 25. Take a look at 50Hz. You're typical 2000 watts into 4 ohm amp is going to be seeing 25 ohms and pumping out only ~300 watts! That's not gonna be too hard on the amp or woofer... see what i mean about "average power"

more so, its not about how much power it takes thermally.... every subwoofer vc is made from either copper or aluminum and so they all pretty much take it the same way! That is as any piece of copper or aluminum will take it. The glues on the vc are actually what fry, not the coil itself, not all glues are the same, but lets not get too detailed here. The cooling differences between subs are more or less minor (cooling is very overrated/overmarketed btw, much in the same way power handling is).Most of the difference from power handling is going to be in terms of VC size. The other interesting thing is most people mistake larger motors as being able to take "more power," but what is really happening is they are simply more efficient and they make more SPL given the same power – people equate more SPL to more power but in truth its often the case it was simply more motor…. Major difference. We (all of us) are really after SPL/Power not power handling.

its like saying i can type 100 words/minute....vs i can type 100 words / minute with no spelling mistakes. We are really after getting work done, not just typing incoherent words on a screen. Ok enough euphemisms...

Things to consider when you match the amp to the woofer:

1. make sure you have plenty of power (if the drivers is rated for 100 watts and you put 1000 watts on it this is OK, but probably a waste of $ more than risk to the driver)

2. Make sure you're amp can handle (about) the impedance minim load you wire to it.

The worst two things that can occur are amplifier clipping (this is bad because it sounds really really bad) or you burn up your amp (to much current pulled for a given voltage.. .in other words to low of a resistance)

Burring up your woofer is RARE and there is no way to tell where that happens... most warning signs are

1. you smell it buring,

2. you hear it distorting - but that’s not always given)

3. The most obvious tell tail sign is you notice is getting more quite..... this is woofer innate way of protecting itself, its called power compression and this occurs when the aluminum or copper wire heats up so much that you start to get a higher resistive load and your amp puts out less power (at the same voltage) If that is happening and you turn up the gain on your amp to compensate or you left it keep playing you're driver's vc might burn. All voice coils will experience the same SPL loss amount at the same relative temperature increase so it’s a nice way to telling when too much is too much for a big woofer and even a small one.

 

[dman4486 5,000+ posts]

once in awhile i do this because i hate stupid questions.
power is not *that* important for subs (it is, but not to the exact people ask about it), i mean even if you buy a 2k amp and you're pulling 2k from it at one point, that’s only going to be one frequency on your system and on average, even at max output, your amp is going to do fall less than 2k unless you're running pure sinwave to it during a test. Most of these switching amps cant even do their RMS for very long so, if you put a linear amplifier at 2k and hooked it up to a sub and pulled 2k from it, i'm sure you will kill any driver under the sun with enough time.

most of the time you DONT run it at max and most of the time you DONT run a sinewave at an impedance minimum, on average subwoofers see FAR less power than you would ever expect.

found that pic on goolge.... looks like a 4th order vented box for an 4 ohm vc....(not for car audio) its only at 4ohms at 25Hz it would normally be filtered below that so it wont reach much below 25. Take a look at 50Hz. You're typical 2000 watts into 4 ohm amp is going to be seeing 25 ohms and pumping out only ~300 watts! That's not gonna be too hard on the amp or woofer... see what i mean about "average power"

more so, its not about how much power it takes thermally.... every subwoofer vc is made from either copper or aluminum and so they all pretty much take it the same way! That is as any piece of copper or aluminum will take it. The glues on the vc are actually what fry, not the coil itself, not all glues are the same, but lets not get too detailed here. The cooling differences between subs are more or less minor (cooling is very overrated/overmarketed btw, much in the same way power handling is).Most of the difference from power handling is going to be in terms of VC size. The other interesting thing is most people mistake larger motors as being able to take "more power," but what is really happening is they are simply more efficient and they make more SPL given the same power – people equate more SPL to more power but in truth its often the case it was simply more motor…. Major difference. We (all of us) are really after SPL/Power not power handling.

its like saying i can type 100 words/minute....vs i can type 100 words / minute with no spelling mistakes. We are really after getting work done, not just typing incoherent words on a screen. Ok enough euphemisms...

Things to consider when you match the amp to the woofer:

1. make sure you have plenty of power (if the drivers is rated for 100 watts and you put 1000 watts on it this is OK, but probably a waste of $ more than risk to the driver)

2. Make sure you're amp can handle (about) the impedance minim load you wire to it.

The worst two things that can occur are amplifier clipping (this is bad because it sounds really really bad) or you burn up your amp (to much current pulled for a given voltage.. .in other words to low of a resistance)

Burring up your woofer is RARE and there is no way to tell where that happens... most warning signs are

1. you smell it buring,

2. you hear it distorting - but that’s not always given)

3. The most obvious tell tail sign is you notice is getting more quite..... this is woofer innate way of protecting itself, its called power compression and this occurs when the aluminum or copper wire heats up so much that you start to get a higher resistive load and your amp puts out less power (at the same voltage) If that is happening and you turn up the gain on your amp to compensate or you left it keep playing you're driver's vc might burn. All voice coils will experience the same SPL loss amount at the same relative temperature increase so it’s a nice way to telling when too much is too much for a big woofer and even a small one.

nice write up, however I know most of what you posted....my question was intended to be more of a, "will the motor handle 2kw when I want to push it that far". I have 2400wrms@2ohm(birthsheet) from a pair of amps strapped, but what I did not know was what the imp rise would be of the q15 through the freq. range. I have however measured individual coils of the d2(for when I run a pair) driver at rest to be 1.5ohm on the dot and the d1 to be .72, so I will already be pushing the limits of min. impedance.(which I am willing to allow due to imp rise)

 

[Buck 5,000+ posts]

I wouldn't do it //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[vellocet 10+ year member]

Hook it up and find out. Really the only way to tell.

 

[NDMstang65 10+ year member]

So long as you don't get happy with the knobs you'll be fine...

If you get happy with the knobs..you'll break it. But I don't condone running that much power...

Simple as that //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif