Which Speaker Gets What?

[ooteedee]

How do you determine how much peak wattage each speaker actually gets through the crossover in a 3-way cabinet?

Lets say you have a 200 watt capable crossover.

What does the woofer get?

What does the midrange get?

What does the tweeter get?

(I would imagine the tweeter and the mid get the least. )

What's the ratio and how do you match midrange and tweeters for a specific woofer?

Probably an easy question for most of you.....but I can't find one of my speaker books in the house.

[Deang]

What's the ratio...

70/20/10 -- if you're talking horns

...and how do you match midrange and tweeters for a specific woofer?

You better go find that "speaker book".

[Al Klappenberger]

ooteedee,

The power distribution to the drivers is proportional to the distribution of the music it's playing. The majority goes to the woofer and the levels go down as you go up in frequency.

AL K.

[ooteedee]

My question ....how do you match midrange and tweeters for a specific woofer?

I know that you have to match the speakers based on the freq response and the crossover you have but.......

I guess I meant that:

If you have a 100 watt rms 200 peak woofer

What wattage Mid and High do you look for?

By the DeanG's aproximation: 70/20/10

YOu'd only need a 20-40 watt Mid and a 10-20 watt tweeter?

Seems low.

[Al Klappenberger]

ooteedee,

That's an interesting question! I never thought about it! I think I like Dean's numbers. The Khorn distribution is about 100,40,5. I don't remember exactly.

Al K.

[John Warren]

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On 1/29/2005 5:06:12 PM ooteedee wrote:

By the DeanG's aproximation: 70/20/10

YOu'd only need a 20-40 watt Mid and a 10-20 watt tweeter?

Seems low.

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But it "is" reasonable.

SPL is frequency independent. If a tweeter is to produce a 120dB tone say at 10kHz, it moves the SAME volume of air as a woofer producing 50Hz at 120dB. Assume that the woofer and tweeter have the same on-axis sensitivity of 98dB/W/m. That means that each driver must dissipate about 120W RMS to simultaneously maintain the 50Hz and 10kHz frequencies at 120dB. There are plenty of woofers that can dissipate 120W but I don't know of any conventional tweeters that can dissapate 120W yet, 120W woofers are routinely paired with 20W tweeters.

So why does it work?...because the amount of actual information recorded in the HF spectrum is surprizingly low realtive to the LF content. In other words, much of the power in recorded music is well, well below 10kHz. Putting it in "sonic" terms, people don't listen to HF sine waves at volumes that approach the threshold of pain.

Continuing-

Drivers are sometimes given two ratings, one for RMS power and one for "music" power. RMS is the actual steady state power that is required to destroy the voice coil, the RMS values define the thermal limit of the coil under steady state conditions. "Music" (sometimes referred to "program") is a term that losely defines the transient (pulse) power dissipation capability. So the 20W RMS tweeter is able to produce transients that, in power terms, can exceed the steady state power value.

Most conventional tweeters have about the same size voice coils (1" diameter) so the

RMS limits are similar. In other words, unless you get out of the 1" diameter dome-like tweeters, your pretty much stuck with the same sorts of RMS power ratings.