Seas W22 - power rating with 300hz HP filter?

[Defo]

How loud can this driver go, if I use a 24db HP filter at 300hz?

[badman]

Look at the power handling and do the appropriate math with the sensitivity and you'll have your answer.


The short version is- probably somewhere in the 110-120dB range, (LOUD).

[Defo]

Originally posted by badman
Look at the power handling and do the appropriate math with the sensitivity and you'll have your answer.


The short version is- probably somewhere in the 110-120dB range, (LOUD).

Won't the power handling be much higher when I only use it down to 300hz?

[RocketScientist]

In many kinds of music there is still a lot of energy from 300hz - 1000hz so a 300hz HP only helps some. You don't have to worry about excursion limits (Xmax) but the 39mm voice coil can still get too hot with too much power. So it really depends more on what kind of music you play, how compressed the music is, etc.

If you play music with lots of sustained energy in the 300hz - 1000hz region, or push the amp hard into clipping, you could burn up the voice coil with 100 watts. Or if you play really clean music with most of the energy below 300hz, with a wide dynamic range, and keep the amp below clipping, you could safely use 500 watts or even more. So it's more about being smart with the volume control than how big the amp is

But, at some point, the driver will start to compress the output as you try to pump more power into it. That, Xmax, and the thermal power handling are what ultimately limits the maximum short term (peak) SPL (db) you will get. I don't think Seas provides a maximum output spec on their datasheets. But some of the speaker design software programs will estimate it for you.

If you're mainly after LOUD, then you probably want a driver with higher efficiency. The W-22 is only 88db/watt.

[StigErik]

Power handling will be the same, but the power delivered to the midrange will be less than the total applied power to the speaker, because the frequency band is limited. That is with music signal of course.

Also consider that peak music power is approx 8 times greater than the average (RMS) power. That means that the W22 is capable of 1000W long-term peak music power, since the long-term power handling is 120W. When the frequency band is limited to 300-2000 Hz, I would guess you could at least triple that number. Lets say 3000W peak music programme, or at least 120 dB peak.

[RocketScientist]

Originally posted by StigErik
Power handling will be the same, but the power delivered to the midrange will be less than the total applied power to the speaker, because the frequency band is limited. That is with music signal of course.

Also consider that peak music power is approx 8 times greater than the average (RMS) power. That means that the W22 is capable of 1000W long-term peak music power, since the long-term power handling is 120W. When the frequency band is limited to 300-2000 Hz, I would guess you could at least triple that number. Lets say 3000W peak music programme, or at least 120 dB peak.

The above would be valid if the W22 could *really* handle 120w of continuous average RMS power. But it can't. It will smoke. When speaker manufactures say "long term power" they're already talking about music power not average RMS power.

For those who don't believe this, just try running even a 50 watt RMS sinewave into an 8 inch/22cm woofer with a 1.5"/39mm voice coil for more than a few minutes and see what happens! A really large subwoofer driver can handle a lot more continuous power, but not a driver like the W22--especially when it won't get much air cooling from cone movement with a 300hz HP.

EDIT: And you can't assume that >66% of the music energy is below 300hz either. If you look at a spectrum analysis of real music you'll see it really depends on the music. Lots of music, at times, has most of its energy above 300hz. If you are after maximum db it's usually much better to get it with higher efficiency speakers. A driver with 94db/watt efficiency will play as loud with 100 watts as the W22 will with 400 watts.

[StigErik]

You're right!

Seas say this about power handling measurements:

Power data is given with reference to IEC 168-5. The signal is white noise, shaped to a defined spectrum, and amplitude limited so that the peak voltage is two times the RMS voltage.
The maximum noise power which the drive units can take without permanent damage for sixty cycles consisting of one second ON and one minute OFF is the specified short term maximum power.
The specified long term maximum power is defined as above but with ten cycles consisting of one minute ON and two minutes OFF.
The mounting conditions in the above tests and during the sound pressure frequency response measurement are identical.

[RocketScientist]

Originally posted by StigErik

Power data is given with reference to IEC 168-5. The signal is white noise, shaped to a defined spectrum, and amplitude limited so that the peak voltage is two times the RMS voltage.
The maximum noise power which the drive units can take without permanent damage for sixty cycles consisting of one second ON and one minute OFF is the specified short term maximum power.
The specified long term maximum power is defined as above but with ten cycles consisting of one minute ON and two minutes OFF.

Yes. So Seas idea of "short term" power is 1/60 continuous power and "long term" is 1/3 continuous power. So that says the W22 is likely risking mechanical damage (i.e. Xmax limit) with anything over 300 watts from a full range signal.

And the spec also implies the voice coil has a thermal limit of around 1/3 of 120 or 40 watts. And even that seems a bit optimistic and is probably helped by the "shaped" white noise signal used further reducing the total average energy.

How much energy the music has above 300hz and the peak to average ratio of the music is what will limit the power handling above 300hz. And that depends entirely on the music. Highly compressed heavy metal rock pushed to clipping, for example, could likely damage a W22 with even a 120 watt amp used with a 300hz HP.

[Defo]

Originally posted by RocketScientist


Yes. So Seas idea of "short term" power is 1/60 continuous power and "long term" is 1/3 continuous power. So that says the W22 is likely risking mechanical damage (i.e. Xmax limit) with anything over 300 watts from a full range signal.

And the spec also implies the voice coil has a thermal limit of around 1/3 of 120 or 40 watts. And even that seems a bit optimistic and is probably helped by the "shaped" white noise signal used further reducing the total average energy.

How much energy the music has above 300hz and the peak to average ratio of the music is what will limit the power handling above 300hz. And that depends entirely on the music. Highly compressed heavy metal rock pushed to clipping, for example, could likely damage a W22 with even a 120 watt amp used with a 300hz HP.

Hmm, disappointingly low headroom in that case...

[RocketScientist]

Originally posted by Defo


Hmm, disappointingly low headroom in that case...

"Headroom" is usually different than maximum power handling. Usually headroom is the peak short term limit. As I said above, 3 things limit how loud a speaker can get:

1 - Mechanical limits of the suspension or voice coil travel (Xmax). This can limit peak headroom, but it's not a problem for the W22 with a 300hz HP filter.

2 - Thermal limits over time. This is how much average power the driver can handle before the voice coil is damaged from heat.

3 - Maximum output. All drivers become less linear at high power levels. For a variety of reasons they start to compress the audio signal as they approach their maximum peak output. It's usually a combination of their efficiency, size (i.e. how much air they can move), moving mass, voice coil heating, and limits of the motor system (i.e. magnetic force, etc.).

Of the above, the 3rd one is what's going to limit the W22's peak headroom. Because Seas doesn't spec the max output, your best bet is to let a good software program estimate it from the Thiel Small parameters.

High-end drivers like the W22 are usually designed mainly for sound quality, not maximum db. You're likely better off with a more efficient driver if you want levels over 110db.