# How much power does a tweeter really need?



## BEAVER (May 26, 2007)

Is it possible to get quality sound running your tweeters directly off the head unit?


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## SteveLPfreak (Sep 26, 2005)

Absolutely. I run BG Neo3 tweets. They are efficient and usually require just a few watts to scream. I've also used some much less efficient tweets and they still only required 10 - 20 watts, give or take, depending on listening habits. You shouldn't have any trouble using the HU to power your tweets.


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## BEAVER (May 26, 2007)

Thanks. I'm still debating which amp to purchase and this helps. I'm looking for a single amp solution power everything and have been torn between the Memphis MCA-5004 and the Baby Belle. I want the extra power of the 5004, but want to still be able to attempt an active set-up. If I can power the tweets with the head unit, I should be in good shape...


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## slow2.2sonoma (Jul 9, 2006)

at least 500RMS each! 


j/k I plan on running 50+ RMS to my Hiquphons someday. Already got the amp and just need the tweets...


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## michaelsil1 (May 24, 2007)

slow2.2sonoma said:


> at least 500RMS each! ...




I wouldn't want to ride with you.


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## 89grand (Nov 23, 2006)

I'm sure they'll run off the HU, but I feel better knowing I have an amp on mine.


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## BEAVER (May 26, 2007)

This topic seems pretty debateable, so I ordered the Baby Belle, just to be sure I have enough for the tweets... Now I can only hope that it has enough power for the mids! Decisions, decisions...


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## Hillbilly SQ (Jan 26, 2007)

if all else fails you can get the mca150 for the tweets later and bridge the belle to the mids. that said i'm sending around 60rms to each of my lotus tweets and it's almost not enough.


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## fej (Feb 8, 2006)

I like headroom .. but tweets really do not need a lot of power to get loud. I have 2 extremes between my 2 cars right now ... 30w to the tweets in the vette and 165w to the tweets in the truck   At some point if the truck ends up a 3 way I will find another small 30-50w amp to run them on and put the 165w on the mids and midbass.

I am not a fan of the HU power thing simply because so few of those watts are "clean" watts ..especially when you get up in the db's. 14w on a tweet works for many people and that is roughly the useable watt total you get from a HU amp in my experience. I think you have to consider the crossover point a little as well as if you are trying to play 2k-20k out of a tweet the 14w might not get it done very well.


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## CASPER97TA (Jun 5, 2007)

I run a set off my headunit. and I have a set amped. You can usually get tweets pretty loud from headunit power.


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## MarkZ (Dec 5, 2005)

There's a lot of confusion with this issue, because most people have difficulty distinguishing between average power and power requirements for transients. When you decide on the size of an amplifier, you're not concerned with the average power that the speaker will dissipate. You're concerned with the peaks. Yes, it's true that a sensitive tweeter mounted in close proximity will probably use single-digit watts (average power) even at loud volumes, but the transients will require several dB more.

Most people take this into consideration when deciding what amplifiers to use on the midbass drivers. How come no one ever thinks of it when they're looking to power their tweeters? Is there a (mistaken) assumption out there that high frequencies in music don't have a transient nature? 

With so much emphasis placed on harmonic distortion, it's surprising to me that people love to use small amps. It's very easy to clip a speaker, and when you do, you're introducing much more distortion than the inherent harmonic distortion attributes of the speaker.

Anyway, the answer to the question requires knowing the sensitivity of the tweeter, where it's going to be mounted in relation to the listener, the xover parameters, and the listening habits of the listener. For most applications, I would recommend more than the ~20w coming from most head units.


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## CMR22 (Feb 10, 2007)

Its interesting to see the different opinions on this subject, and many others. Everything from running the tweeters off a head unit to someone who planned on running them off a 400 watt x 2 at 4 ohm amp.  

http://www.diymobileaudio.com/forum/showthread.php?t=15663


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## quality_sound (Dec 25, 2005)

I ran a bridged 4150XXK to mine, but it was passive so that soaked some of it up.


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## 89grand (Nov 23, 2006)

MarkZ said:


> With so much emphasis placed on harmonic distortion, it's surprising to me that people love to use small amps. It's very easy to clip a speaker, and when you do, you're introducing much more distortion than the inherent harmonic distortion attributes of the speaker.



I hate small amps. I have a 600 watt mono sub amp and 100x4 amp on my mids and tweeters for a total of 1000 watts, and there are times I wish I had twice that much power.


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## ATB (Aug 30, 2005)

Some of us have small cars and/or electrical systems. Also, isn't it true that higher frequencies require less power?


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## 89grand (Nov 23, 2006)

ATB said:


> Some of us have small cars and/or electrical systems. Also, isn't it true that higher frequencies require less power?


Sure, I still wouldn't run a tweeter on a 15 watt amp though.


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## BEAVER (May 26, 2007)

This has been pretty interesting, to say the least... I'm half tempted to start another thread... _How much power does a mid really need?_


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## CMR22 (Feb 10, 2007)

ZR2003 said:


> This has been pretty interesting, to say the least... I'm half tempted to start another thread... _How much power does a mid really need?_


Do one for midbass also


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## 89grand (Nov 23, 2006)

ZR2003 said:


> This has been pretty interesting, to say the least... I'm half tempted to start another thread... _How much power does a mid really need?_


Well that's not easy to answer. How loud do you want to get? If it's just for background music in a quiet environment, a couple of watts of power is pretty loud. You you want to get loud in a car and have headroom, you'll need a lot more than a couple of watt.

A lot of things some into play though, how efficient is the speaker, what frequency range will it be playing, how loud do you want it. 

I guess to determine how much power a speaker needs, you'd need to to test it to determine how much power pushes the speaker to it's maximum output. If a speaker reached it's limit with 100 watts, a larger amplifier would not help as it would only lead to over excursion and heat. Once you've reached the speakers limit with power, the only way to get louder is to add more drivers.

Usually though, in most sytems, you'll hear the amplifier running out of steam before you hear the speakers limit, assuming you're using the speaker within its intended frequency range.

Most of us here probably do not have enough amplifier power to push our drivers to their maximum potential.


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## MarkZ (Dec 5, 2005)

ZR2003 said:


> This has been pretty interesting, to say the least... I'm half tempted to start another thread... _How much power does a mid really need?_


Depends. As 89grand said, it's going to depend mostly on the efficiency of the speaker/enclosure; proximity and aiming; "tuning" parameters like xover points, phase/delay, etc; and also the spectral content of the music (including after you've boosted the bass, cut the midrange, or whatever other preferences people like to go for).

And yes, proximity and aiming applies really to all the speakers in the system. Off-axis tweeter mounting can yield appreciable attenuation above a couple kHz. Reflections, delay, and phase can result in huge differences in output using the same speakers in different locations. Even subwoofer positioning will often yield tremendous differences in output.

So you want an easy answer to the question? Too bad.  

What I don't understand though is the current trend of delivering several hundred (or even thousands) watts to a relatively efficient subwoofer setup and then doing things like running tweeters off the 15w head unit, or running 4" mids on 25 watts a piece to cover 4 octaves.


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## 89grand (Nov 23, 2006)

Yeah, I'm a weirdo, in my Jeep, I run my MB Quarts and Focal tweeters through a passive crossover with my PPI A600.2, then I use my PPI A200 to power my 2 JL Audio 10" subs.

What I had found was that running the system using conventional wisdom, the A600.2 on the subs and A200 on the mids and tweeters was that I wasn't using anywhere near the A600's potential because it's a fairly balanced SQ oriented setup.

Now, when I switched amps and used the much more powerful A600.2 on the mids and tweeters was the system had so much more dynamics and got considerably louder, yet the subs with the smaller A200 seemed to be as loud as they where before, obviously that's because the A600.2 was just loafing along.

Lesson here:
Never underestimate the importance of high power to your mids and tweeters, and that subs can get quite loud with relatively low power.


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## andoneward (Aug 19, 2009)

Resurrecting this thread from the dead because of the "search".....

I am toying with the idea of using the MS-8 internal amplifier to power the two tweeters when I start my build. This would allow me to free up two channels of an amplifier and I could get away with a single 5 channel amp for a 3-way active + sub. Maybe a JL HD900/5 or something...

Any thoughts or experience with 20 watts to some nice tweeters?


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## alachua (Jun 30, 2008)

Andy from JBL has recommended against this. Since the MS8 will attempt to level match the front speakers to the same relative output, you may end up sacrificing overall output as it brings the midrange/midbass down to match the output of the tweeters. This can be further compounded if, in doing this attenuation and the equalization, the MS8 runs out of cut in a specific frequency range. 

Have you considered using a passive xover between the midrange and tweeter as an alternate solution?


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## andoneward (Aug 19, 2009)

I missed that note considering i've read many pages of that thread. I have thought about doing the passive crossover for the mids/tweets which was recommended on that thread in order to have the rearfill accounted for in two of the 8 channels.
i'll have to reattack my build plans. Thanks!


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## alachua (Jun 30, 2008)

Any time. For reference, I am using a JL 450/4 for my front 2 way, and running the rear off the MS8 amp. After a bit of testing, I found it to work well thus far. I am probably going to add another JL 300/4 eventually do handle center channel duty. The crossover on the amp will allow me to do this without using 2 outputs on the MS8.


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## MarkZ (Dec 5, 2005)

Would work if the crossover point is high enough.


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## chad (Jun 30, 2005)

FWIW I run my tweets of the 25W/Ch section of a Jay eL 500/5 and they NEVER EVER show signs of under powering, not even when being stupid.

I suspect the MS8 channels will be more than enough.

If I had a MS8 I'd do exactly the same and add a big 4 channel for the mid/bass and bridged to the sub on 2 other channels.

Golden.


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## MarkZ (Dec 5, 2005)

All depends on the crossover point. If I had to guess, even a small tweak from 4kHz down to 2.5kHz is probably on the order of doubling the power for a lot of music.


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## chad (Jun 30, 2005)

even then, 25W on a sensitive tweet, even moderately sensitive will JUST rip.

Example, my PA, big fuggin horns with JBL2445's bolted to them granted. A 225W/Ch amp at 8 ohms, driving 16 ohm horns. AT EAR BLEEDING LEVELS crossed at 1.2K... It occasionally illuminates the signal present indicator on the amp fully


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## andoneward (Aug 19, 2009)

chad said:


> If I had a MS8 I'd do exactly the same and add a big 4 channel for the mid/bass and bridged to the sub on 2 other channels.
> 
> Golden.


I think I might go ahead and try this. If it does not work out, then I'll have to buy a small 2 channel. Otherwise, it might be a win to tap into that power without buying additional equipment.


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## MarkZ (Dec 5, 2005)

chad said:


> even then, 25W on a sensitive tweet, even moderately sensitive will JUST rip.


And you probably don't hear the clipping when you're doing it. The one percenters won't approve.


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## NRA4ever (Jul 19, 2010)

I'm running my 4inch mids & tweeters with 75 watts. I've run these tweeters with 75 watts by themselves I just turn the amp down.


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## chad (Jun 30, 2005)

MarkZ said:


> And you probably don't hear the clipping when you're doing it. The one percenters won't approve.


to hell with them. :laugh:


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## splicer (Oct 4, 2008)

chad said:


> FWIW I run my tweets of the 25W/Ch section of a Jay eL 500/5 and they NEVER EVER show signs of under powering, not even when being stupid.
> 
> I suspect the MS8 channels will be more than enough.


I also run my tweets off the 500/5 25W channels. Not only do tweeters not need more than 25 watts, they also can't take a lot more than 25W. People who think they are 'sending' 100W or whatever to their tweeters don't realize that the crossover is cutting out the vast majority of the power. The crossover does not just block or absorb the power, it prevents the amplifier from putting it out in the first place.

Check out this chart:
http://sound.westhost.com/lrp-f71.gif
90% of the power is under 5.6K
85% is under 2.8K
80% is under 1.7K


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## MarkZ (Dec 5, 2005)

Re-read my post about average power vs. peaks. When determining amplifier sizes, we care about peaks, not average. Tweeters most certainly will see peaks in the neighborhood of (or in excess of) 25w.


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## Allan74 (Jun 17, 2010)

Is there a rough 'Rule of thumb' for the distribution of power over the spectrum ?

Kinda like this *poor hypothetical example* that I whipped up just now.....?










Does anything like this or any reference material such as this exist for real, something easy to understand for dummies, rather than formulas and such ?.....lol


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## MarkZ (Dec 5, 2005)

Yeah, the link in splicer's post shows a very general example. It varies considerably though. And transients can be huge across most of the spectrum.


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## Allan74 (Jun 17, 2010)

MarkZ said:


> Yeah, the link in splicer's post shows a very general example. It varies considerably though. And transients can be huge across most of the spectrum.


I saw that as well, but I was wondering if there was something that could be easilly applied to the entire spectrum....say 25 to 25k, rather than just the somewhat-bandpass-specific example of his ? Basic flat pink noise RTA kind of example to keep things simple and no real high and low transients to account for.......


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## splicer (Oct 4, 2008)

MarkZ said:


> Re-read my post about average power vs. peaks. When determining amplifier sizes, we care about peaks, not average. Tweeters most certainly will see peaks in the neighborhood of (or in excess of) 25w.


I don't know of any reason to believe high frequency peaks tend to be proportionally any higher (relative to average power) than low frequency ones. In fact I suspect the opposite is true because people do not find loud high frequency sounds to be very pleasant. In addition, tweeters tend to be at least as efficient as midbasses and often much more efficient.


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## MarkZ (Dec 5, 2005)

splicer said:


> I don't know of any reason to believe high frequency peaks tend to be proportionally any higher (relative to average power) than low frequency ones. In fact I suspect the opposite is true because people do not find loud high frequency sounds to be very pleasant. In addition, tweeters tend to be at least as efficient as midbasses and often much more efficient.


Measure it in Adobe Audition or Cool Edit Pro or whatever you have. You'll find that transients are remarkably similar at high frequencies than at low frequencies. So yes, it will be proportionally smaller because of efficiency/etc, but in terms of energy content it's still high, especially if you're doing ~3 octaves with your tweeters. For people throwing 1000w at their subwoofer (playing less than two octaves, max), 150w per channel at their midbass drivers, and then filtering their tweeters at 3kHz and using only a 25w amp, it just doesn't add up. Unless they're using crazy inefficient low frequency drivers and then have the tweeters mounted next to their faces.

The saving grace is that humans do a really sucky job at hearing high frequency distortion, and the transients are (probably...) shorter with high frequencies than with low frequencies, which also adds to their inaudibility. I probably clip my tweeters during short transients, but who knows? I can't tell.

BTW, I did some measurements in some songs on here about a year ago, but can't find it. Maybe you guys will do a better job searching than me (I hate the DIYMA search function with a passion...).


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## NRA4ever (Jul 19, 2010)

I have my tweeters running through the crossovers they came with & the other speakers crossed over at my amp. I doubt they are clipping. I have my amp set very low since its only running a pair of 4s & tweeters. I've run this tweeter on this amp for 10 yrs


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## corcraft (Nov 16, 2010)

Ok, I have read this thread like 100 times, searched this topic, called a few engineers and tuners and even started my own thread titled with a ? "tweeter power vs mid pwr?" Because I wanted to know the answer to the riddle myself.

What I have come to find is that there are basically 2 different opinions on how much power the tweeters need even from well known tuners and engineers and the opinions were pretty much 50/50. Half says they need allot of power and half says they need little power but I had trouble getting an explanation that I was comfortable with, well, because there were 2 sides and 1 explanation seemed like it was contradicting the other. Guess what? They were both right! well kind of. I will attempt to explain- markz or any1 else please correct me if I say anything wrong.

The biggest factor in this equation is sensitivity and distance so for this explanation let's assume that both the tweeter and woofer are the same sensitivity and the same distance away from the listener. A change in either of these will make a huge difference- every 3db difference in sensitivity is double a difference in power (example: 87db w/ 100w = 90db w/ 50w). And as for distance- if 1 is half the distance as the other that is roughly 6db difference. Now, back to both being the same distance an sensitivity. Half say that both the tweeter and woofer need the same power because of the same distance and sensitivity. The other half argues that tweeters don't need more than 20w and I said that they're both right and here is why.

Let's use a 100wpc amp to each and a 3khz for the xover point for example. First off no tweeter rated at 100w can take 100w but will take 100w system pwr or in other words a 100wpc amp. Huh? Doesn't that mean they're getting 100w? No, the freq 3k htz and above use roughly 15% of the system power so that would be 15w. So this means that you can run deck pwr right? No, wrong again. Notice that I said that the tweeters use 15% of the system pwr..... 15% of 25 watts (which is way over what any deck actually puts out) is less than 4 watts. So no, I would never use deck power. 

You see? Both sides are right to a degree. Tweeters rarely need over 25w but with the same sensitivity and distance the same system pwr to tweeter and woofer would be imho, a perfect match. The tweeter will never get equal power but its needed to get the desired pwr cleanly. Can you get by with less? Yes, and this is why allot of tuners recommend a less powerful amp on the tweeters to not to waste power and money- the tweeters only need a little power remember? Here is how- You can up the gains on the tweeter amp to get more than 15% of amps power. Done correctly this will only cause minimal harmonic distortion at high volumes. Minimal harmonic distortion is hard to hear at high freq even to trained ears and won't hurt anything if you don't abuse it for long periods of time. So...... you can get by with less power on the tweeters, its just not the "perfect scenario" imho. 

Conclusion: who is right? The 1 that says you need the same pwr or the 1 that says tweeters need less? Both. They don't need the same actual pwr but in a perfect scenario they need the same system power. Can you get by with less pwr on the tweeters? Yes and no one will be able to tell if you don't go overboard.


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## matthewo (Jan 31, 2008)

none of you guys run a pair of us amps 2000x. one bridged to each tweeter???


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## KrackerG (Jan 18, 2011)

not a fan of running anything off the head unit 40w x4 internal amp...i suggest you run it off your mids, just use a passive crosssover before the tweeters


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## SSSnake (Mar 8, 2007)

The amount of power required for a tweeter comes down to a system design issues. Decide what the highest average output level you want for you tweet (in coordiation with the rest of the system) and then decide on how much dynamic capability you want it to have.

e.g. Lets say you have a 90db efficient tweeter (throughout the intended passband), mounted 1 m away and you want 100db average output capability. Then you need to decide how much dyanmic range you want/need (in reality this is likely tied to the type of music you prefer but I am choosing 10db because it makes the math easy). Let's say you want 10db dynamic range at max volume. Well you need 10W to get to your average output goal and 100W to support the dynamic range requirement. Do you need 10db dynamic range? Does an amps dynamic output capability help supply this power? It depends. How long is the transient you want to support? How long was the transient during peak power output testing on the amp? Up for debate...

Now how many people want to claim they can do 120db broadband? Do the math, yep 1000W to tweets! Now look at horns with let's say a modest 100db efficiency. Only 100W. Makes you think twice about all of that cheap power...


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## rufast (Aug 7, 2010)

what 50 watt/100watt 2 channel amp would you use to power up a good set of tweets?


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## SSSnake (Mar 8, 2007)

Not to be a smartass but a 50W/100W 2 channel amp. Any amp... I'm not a big believer in amplifier sonics so just pick what you want that delivers the power and will last and be as reliable as you want. If I were picking, I would choose one of the new High Efficiency amps out there.


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## mitchyz250f (May 14, 2005)

I am working from memory here, but my understanding is the power required above 500 Hz and below 500 Hz is equally divided. And the power to run above 3k Hz is only about 10% of the total power needed for the full system. Assuming all speakers have equal efficiency. This is from 'The Car Stereo Cookbook. So if you are using 400 watts total per side, the author is suggesting you need 40 watts for the tweeters. If your tweeters were 3 db more sensitive, then you would need 20 watts. 

Now I have a question, amps are usually rated 20-20k. With an electronic crossover the amp is making power over the specified range only. So is a 20 watt amp producing power over 10% of its range (3K and up) really making 200 watts over the specified range. 

Don't blast me, just asking a question.


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## corcraft (Nov 16, 2010)

mitchyz250f said:


> I am working from memory here, but my understanding is the power required above 500 Hz and below 500 Hz is equally divided. And the power to run above 3k Hz is only about 10% of the total power needed for the full system. Assuming all speakers have equal efficiency. This is from 'The Car Stereo Cookbook. So if you are using 400 watts total per side, the author is suggesting you need 40 watts for the tweeters. If your tweeters were 3 db more sensitive, then you would need 20 watts.
> 
> Now I have a question, amps are usually rated 20-20k. With an electronic crossover the amp is making power over the specified range only. So is a 20 watt amp producing power over 10% of its range (3K and up) really making 200 watts over the specified range.
> 
> Don't blast me, just asking a question.




a 200 watt amp with gains set to 0db will be pushing roughly 30 watts. It depends on the type of music but 15% of the power is roughly what the freq above 3k use. I touched on this earlier, this doesn't mean that you can use a 30 watt amp because then those freq would be using 15% of that which is 4.5 watts. You can get by with less power by adjusting the gains to like +5db but you would still need more than 20 watts unless your tweeters are cloer to you or they have a higher sensitivity.


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## rugrat (Feb 17, 2009)

mitchyz250f said:


> I am working from memory here, but my understanding is the power required above 500 Hz and below 500 Hz is equally divided. And the power to run above 3k Hz is only about 10% of the total power needed for the full system. Assuming all speakers have equal efficiency. This is from 'The Car Stereo Cookbook. So if you are using 400 watts total per side, the author is suggesting you need 40 watts for the tweeters. If your tweeters were 3 db more sensitive, then you would need 20 watts.


"The Car Stereo Cookbook" suggestion, is similiar to the chart that was posted earlier by splicer


splicer said:


> Check out this chart:
> http://sound.westhost.com/lrp-f71.gif
> 90% of the power is under 5.6K
> 85% is under 2.8K
> 80% is under 1.7K


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## Aaron'z 2.5RS/WRX (Oct 24, 2007)

Can't remember the car, but back in the 90's there was an oldschool car with oldschool PPI Art amps

Had a PPI 2250 (2150?) on the TWEETERS..??? 

I don't recall exactly i'm not much of a PPI guy.. largest amp in the system was on the tweeters.. 

So what's up with that... ?? Zero gain, all dynamics??


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## razholio (Apr 15, 2008)

89grand said:


> Yeah, I'm a weirdo, in my Jeep, I run my MB Quarts and Focal tweeters through a passive crossover with my PPI A600.2, then I use my PPI A200 to power my 2 JL Audio 10" subs.
> 
> What I had found was that running the system using conventional wisdom, the A600.2 on the subs and A200 on the mids and tweeters was that I wasn't using anywhere near the A600's potential because it's a fairly balanced SQ oriented setup.
> 
> ...


AMEN BRUTHA! as Patrick Bateman has pointed out, the cabin-gain in the sub freqs make those easy, especially from a large, properly-enclosed sub driver. It's the midbasses which are frequently only around 6.5" that have to take over from the 10-12" sub right around 100hz where cabin-gain starts to drop off... This is exacerbated by typically poor midbass enclosures due to space constraints up front in a car.

I have a 'mere' 300W to my 12" sub, 600W to a quad of 6.5" midbasses, and 150W to a pair of tweeters, and I don't listen to my music very loud. My SBAcoustic tweets can handle a fair amount of power (something like 45watts or so), but my biggest reason for the tweeter power overkill? I don't want *any* chance they'll receive a clipped signal as that is the most likely way they will get damaged...


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## mitchyz250f (May 14, 2005)

Dynamics in the midrange and mid-bass are just as challenging as the treble region if not more so. If the tweeter is making 15% of the total accoustical output, there is no explanation for providing half the power to it. Chad does this for a living and thinks that 20 - 25 watts is enough (post 27).


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## corcraft (Nov 16, 2010)

mitchyz250f said:


> Dynamics in the midrange and mid-bass are just as challenging as the treble region if not more so. If the tweeter is making 15% of the total accoustical output, there is no explanation for providing half the power to it. Chad does this for a living and thinks that 20 - 25 watts is enough (post 27).



There are other factors too like I mentioned in my 1st post- Sensitivity and distance.

Example: if you have your tweeters half the distance away from you as your mid (that's 6db). You're mids have a sensitivity of 88db and you're tweeters have the sensitivity of 91db which is not uncommon (that's another 3db). That put's you at a 9db difference which would be equal to 100w on the mids and 12.5 watts on the tweeters. Now, you can also crank the gains about another 5db safely and never hear the hd which puts the tweeters need for power in this scenario down to even single digit #'s. 

If you're speakers and tweeters are an equal distance away and the same sensitivity then equal power would be a perfect scenario. Can you get by with less? Yes, by tweaking the gains but I wouldn't crank the gains a past 5db.


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## tnbubba (Mar 1, 2008)

as much as it can handle!


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## mitchyz250f (May 14, 2005)

tnbubba said:


> as much as it can handle!


What does that mean?


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## tnbubba (Mar 1, 2008)

as much as it rated for.. good tweet manufactures will post max and long term rms power rating as what freq and crossover slopes they tested those rating at.


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## corcraft (Nov 16, 2010)

tnbubba said:


> as much as it rated for.. good tweet manufactures will post max and long term rms power rating as what freq and crossover slopes they tested those rating at.



But remember this is system power and not actual power! so 100w is more like 15-20w @ 0db gain. Also you have to match it to you're other drivers so 100w to a 88db sensitive mid and 100w to a 91db sensitive tweeter @ the same distance would be overkill for the tweeter. There would be no problem running a 100w amp to them but not necessary because you would be turning the gains way down to match the mid.


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## tnbubba (Mar 1, 2008)

power is power you are confusing acoustical power with electrical power. yes tweets are more efficient and usually by 3db so cut your amp power down to 50 watts( ref 100W) or turn the gain down..that way you have 3db of dynamic headroom left on the tweets(if you turn the gain down)

if you run your tweets as low as 1.5K you are using up 40% of the music(acoustic) power spectrum... that head room doesn't hurt.. would you only put 50 watts to your $300 SS tweets if they took 250W?


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## corcraft (Nov 16, 2010)

tnbubba said:


> power is power you are confusing acoustical power with electrical power. yes tweets are more efficient and usually by 3db so cut your amp power down to 50 watts( ref 100W) or turn the gain down..that way you have 3db of dynamic headroom left on the tweets(if you turn the gain down)
> 
> if you run your tweets as low as 1.5K you are using up 40% of the music(acoustic) power spectrum... that head room doesn't hurt.. would you only put 50 watts to your $300 SS tweets if they took 250W?




If power was power then try this. Put a 200wx2 amp on your tweeters and crank it and then put the same amp on your subs and crank it........ the sub will prob dim the lights on any stock electrical system because it will require more volts and current to produce the watts, the tweeter won't because they will never use the power, actually only about 20%-25% so 40-50 watts of it at a 1.5k xover point. Also if power was power then you would be getting 100w to you're system all of the time. I don't know of any tweeter that can actually take 100w even if its rated at 250w.

As for would I put 50w amp on a 250w tweeter? Well it depends on the locations, sensitivities, xover points and power to the rest of the system. There are numerous instances were that would be more than enough.


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## tnbubba (Mar 1, 2008)

Power Handling
Zn 4 ohm 100h RMS noice test (IEC) - W
Zmin - ohm Long-term Max Power (IEC18.3) 550,0 W
Zo 11 ohm Max linear SPL (rms) @ power dB/W

550 W straight off scan speak spec sheet!!!!
higher impedence of tweets = less current!!!
you missed my point about headroom too..


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## corcraft (Nov 16, 2010)

tnbubba said:


> Power Handling
> Zn 4 ohm 100h RMS noice test (IEC) - W
> Zmin - ohm Long-term Max Power (IEC18.3) 550,0 W
> Zo 11 ohm Max linear SPL (rms) @ power dB/W
> ...



Most tweeters that I have used (other than quarts) are the same impedence as most mids (4ohm). Even less per say because a woofer changes impedence as it moves creating resistance where a tweeter stays pretty close to the resistance (4ohms)........ also, if the tweeter is a higher resistance than it is getting even less power than what I listed above on a given amp because a 200wx2 amp is now only a 150wx2 amp if the impendence is 6ohms.

IMHO, the reason that quart used a 6ohm tweeter is because their woofers had a really low sensitivity. For instance, my qsd216 mids had a sensitivity of 85db the qtd25 tweeter had a sensitivity of 90db so by making the imedence higher on the tweeter it would match better with the 4ohm mid with the same power.


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## corcraft (Nov 16, 2010)

Here is a good link about powering tweeters. 


Why Do Tweeters Blow When Amplifiers Distort?


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## tnbubba (Mar 1, 2008)

ok how many of you have blow tweets??
main reason.. too little power and the amp CLIPS!
How many have you blown from thermal overload?
can you take a tweeter apart and tell the difference?? I can. Usually..there are always some exceptions.

I can take a 40 watt cheap a** vifa tweet.. and put over 100W burst tone thru it with no ill effects.. 50 watts pinks noise and a few hours, the voice coil is toast.
MUSIC IS DYNAMIC!(well except for today compressed *zz crap) 3 db of head room is double the power. If your tweeter takes 50 watts you are not going to blow it with a 100 watt amp IF your gains are set properly(assuming tweet is 3 db more efficient than the driver below it and you have it crossed over properly). But you will have 3db of head room for dynamic peaks available. (shoot the same applies to all drivers). AGAIN GOOD manufactures will rate the drivers at power rating WITH crossover Freq and slopes that they test at. Ok now go buy some JBL 2" horns drivers that take a 1oooW and add a crown K2 on them @ 1800W and screw u spl crowd.LOL How do u think outdoor concerts get to 120db!


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## corcraft (Nov 16, 2010)

ok, now we are almost on the same page. That is pretty much to the T of what I have been saying. You will not blow a tweeter with a 100w amp and I recommended that you put a 100w amp on your tweeters if you have 100w on your mids if they are the same distance an sensitivity but that doesn't mean that they will be using 100w or even half of it with music. Now, to the pink noise; That is when power is power like you said above. 100w of pink noise with will fry every tweeter that I know of quick, fast and in a hurry which is why most tweeters are not rated at actual power but sytem power because no 1 rides around listening to pink noise- that I know of anyway, lol. 100w of music power is typically 15-25% of the system power in the tweeter freq's depending on the xover point. A 100w tweeter can not take 100w this is why pink noise frys them but it can tak a 100w amp which is 15-25w at its freq's with music.


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## tnbubba (Mar 1, 2008)

be careful
with todays compressed crap recording you approach pink noise powel levels some recordings have less than 6db of hedroom.. and if you lower crossover freq to 1.5k like a good 2 way system that tweet power goes up to like 40 % 3K is one octave higher.. and there is a ton of acoustic output between 1-3 K..i may be a few percentage off I can't find my chart right now.


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## corcraft (Nov 16, 2010)

AGREED!!!!!! thats why I have a turntable and only play vinyls in my car!!!!!!!!! JK, but I wished!!!! I def never play downloaded material though and rarely ever listen to new recording because of the new junk.


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## tnbubba (Mar 1, 2008)

yea i got my 15 and 30 IPS tape reels in mine!


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