Is there a W rule of thumb?

[eriksquires]

When we think about watts in a multi way speaker, are there any convenient, fact based rules for how power is distributed in music an therefore drivers?

 

[Galu]

According to Eminence:

"As a general rule of thumb, we estimate that the high frequency driver will see about 20% of the system power with a 1.5 kHz-2.5 kHz crossover, 15% with a 3.5 kHz-5 kHz crossover, and 10% with a 5 kHz and up crossover (all based on a minimum 12dB/octave slope)."

https://eminence.com/blogs/blog/high-frequency-driver-power-handling

 

[454Casull]

With a 2-way crossover, the 50-50 power split is generally something in between 300-500 Hz in most types of music.

 

[AllenB]

Thread 'Spectrum of Musical Genres'

2017-08-08 8:49 pm

I thought you might find this interesting. It's the spectral content of music visualized. You can see the tonal balance of different types of music.

The graphs below are FFT analysis of different music genres. The files analyzed for the this test are the average of approximately 112 different recordings in each genre. I averaged those recordings and plotted the spectrum.
Note that the graphs do NOT show how loud the tracks were mastered, because all tracks were normalized before averaging them. That allows for the overlay on one of the plots. The plots just show tonal balance. You...

• Pano
• Replies: 89
• Forum: Everything Else

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[Galu]

From the Eminence Loudspeaker Book:

Crossover frequency (Hz)	Percentage power above crossover point
150	80
200	72
300	55
500	40
1000	25
3000	20
5000	10

 

[Moondog55]

Obviously ignoring people who use DSP to boost bass by 12dB but that old RoT of a split at 300Hz has usually worked for me; especially when using cheap Bi-Amping crossovers like the Behringer

 

[AllenB]

that old RoT

Rule of Thumb. On second read I found the meaning changed quite for the better 😀

 

[eriksquires]

@Galu

Thanks for that. I'm honestly a little surprised the typical subwoofer crossover area (~80Hz) doesn't reduce power nearly as much as I though. I thought that would be the 40-50% point. That doesn't happen until ~ 300 Hz according to that.

I'm thinking a lot about 2-way vs. 3-way speakers and 2-way vs. 2-way plus subs as I approach my next project. I'm converting a 2-way with 6.5" mid-woofer to a 3-way and based on this chart it seems the reduction in energy in the (currently) midwoofer is substantial.

 

[phase_accurate]

I guess they were assumimg equal efficiency over all the ways. When a sub is capable of really deeeeeeeep bass then it usually has amn efficiency that is much lower than all the other drivers in the speaker. In this case the "150Hz/80% above" rukle will not be valid anymore.

Regards

Charles