Comparing Subwoofer Power Rating

[AcuDefTechGuy]

My DefTech BP7000SC has a built-in sub with a power rating of 1800-watts RMS and my CLR-3000 has a built-in sub with a power rating of 150-watts RMS.
So I called a DefTech customer rep and asked about it.
He said the BP7000SC's sub is rated at 1800-watts RMS into 25 ohms, and the CLR-3000's sub is 150-watts RMS into 60 ohms.

Do all subwoofers have impedance load of 25-60 ohms?
I guess you can't really compare this to regular amps & speakers since they are usually 2-8 ohms.

 

[ParadigmDawg]

Mine is rated at 4500 watts Dynamic Peak / 1500 watts RMS Sustained but I cant find where they provide more specs on ohms or distortion.

 

[AcuDefTechGuy]

Mine is rated at 4500 watts Dynamic Peak / 1500 watts RMS Sustained but I cant find where they provide more specs on ohms or distortion.

Yeah, are they trying to hide something? I mean every speaker has at least an impedance rating, and all amps have impedance & distortion ratings. But subs are almost hush-hush. They only give you one rating--watts. If you are lucky, you might get both a Dynamic Peak & RMS rating. I'm going to ask what is my subs Dynamic just for kicks

But I have never seen THD% on speakers. Why?

 

[Joe Schmoe]

But I have never seen THD% on speakers. Why?

Probably because it depends on the amp as well as the speakers. Subs contain both, which is why they can measure it.
Does the sub deliver the SPL and extension you want with a level of distortion you can live with? If so, I am not sure why other specs matter anyway.

 

[ParadigmDawg]

Oh we always want more; we are addicts!

Probably because it depends on the amp as well as the speakers. Subs contain both, which is why they can measure it.
Does the sub deliver the SPL and extension you want with a level of distortion you can live with? If so, I am not sure why other specs matter anyway.

 

[Seth=L]

Probably because it depends on the amp as well as the speakers. Subs contain both, which is why they can measure it.
Does the sub deliver the SPL and extension you want with a level of distortion you can live with? If so, I am not sure why other specs matter anyway.

The THD% spec is for the amplifier only.

 

[AcuDefTechGuy]

Probably because it depends on the amp as well as the speakers. Subs contain both, which is why they can measure it.
Does the sub deliver the SPL and extension you want with a level of distortion you can live with? If so, I am not sure why other specs matter anyway.

Oh, my subs (two 14" 1800-watts RMS & one 10" 150-watts RMS) deliver enough bass, but I'm always curious.
If you get a sub with a separate amp (like NHT subs), you get the power rating like 200-watts RMS into 8 ohms w/ 0.01 % THD < 1 kHz. But when you get a sub with in internal amp, they don't tell you anythingm, except "200-watts". So I'm just curious about the actual impedence load and THD% of the amp section.

 

[AcuDefTechGuy]

Oh we always want more; we are addicts!

That's right. If they made a 20,000-watts RMS subwoofer into 8 ohms w/0.0000001% THD from 1 Hz - 100 kHz, who would not want that? I mean C'mon. Who in his right mind wouldn't want that?

 

[ParadigmDawg]

220...221...whatever it takes...

 

[mtrycrafts]

That's right. If they made a 20,000-watts RMS subwoofer into 8 ohms w/0.0000001% THD from 1 Hz - 100 kHz, who would not want that? I mean C'mon. Who in his right mind wouldn't want that?

I don't know who would or why they would want it at home.

Firstly, most cannot tell 10% distortion in subs, hence they rate subs output at 10% THD.
Second, you might need a bigger service panel for such an amp.

 

[Kabir424]

Also, does anyone know how BASH amps compare in their specs from other sub amps?

 

[Vaughan Odendaa]

Comparing subwoofer power ratings is a rather futile exercise because the amount of power required from the driver is dependant on enclosure size.

My SVS PB10 ISD only has a 300 watt amplifier but it smokes some designs that churn out more than 800 watts because the physical box size is massive in comparison. The Sunfire designs are good examples to use because their enclosures are physically small and their drivers are required to move further with a given input level to overcome the great internal air pressure that you would no doubt get in such a compact box.

I think it's like 1.6 kilowatts of power or something in those designs. The bigger the enclosure, the less power required to overcome the resistive compliance factor, which is the springy nature of the air inside the box. So comparing power ratings is simply not going to give one an even playing field.

The JL audio subwoofers are good examples of requiring extreme amounts of power to reach full excursion within a moderate size enclosure. But that driver is one heck of a beauty.

Heh.

--Regards,

 

[mtrycrafts]

I think it's like 1.6 kilowatts of power or something in those designs.
--Regards,

Yes, that is the claim and in older models, I think it was claimed 2500watts!!!

But, when Dr. Hsu was posting on the net, was rudely chased away, he showed how it was a useless claim as the amp would do that power under specific conditions that the speaker would never meet

 

[AcuDefTechGuy]

Comparing subwoofer power ratings is a rather futile exercise because the amount of power required from the driver is dependant on enclosure size.

My SVS PB10 ISD only has a 300 watt amplifier but it smokes some designs that churn out more than 800 watts because the physical box size is massive in comparison. The Sunfire designs are good examples to use because their enclosures are physically small and their drivers are required to move further with a given input level to overcome the great internal air pressure that you would no doubt get in such a compact box.

I think it's like 1.6 kilowatts of power or something in those designs. The bigger the enclosure, the less power required to overcome the resistive compliance factor, which is the springy nature of the air inside the box. So comparing power ratings is simply not going to give one an even playing field.

The JL audio subwoofers are good examples of requiring extreme amounts of power to reach full excursion within a moderate size enclosure. But that driver is one heck of a beauty.

Heh.

--Regards,

So you don't think a 800 watts RMS powered subwoofer will necessarily output more bass than a 300 watts RMS powered subwoofer?

In other words, you think it's possible for a 300 watts RMS powered sub to produce more bass impact than a 800 watts RMS powered sub in the same exactly room?

 

[Joe Schmoe]

In other words, you think it's possible for a 300 watts RMS powered sub to produce more bass impact than a 800 watts RMS powered sub in the same exactly room?

Of course it is possible, it is just a function of design. For example, an 18" sub with a 300 watt amp will put out far more bass than an 8" sub with an 800 watt amp, all else being equal.

 

[Vaughan Odendaa]

So you don't think a 800 watts RMS powered subwoofer will necessarily output more bass than a 300 watts RMS powered subwoofer?

Yes.

In other words, you think it's possible for a 300 watts RMS powered sub to produce more bass impact than a 800 watts RMS powered sub in the same exactly room?

Yes. As Joe Schmoe said, it's a matter of design. Sealed designs require more power to reproduce deep bass than ported designs (all things being equal). Enclosure size dictates to a large degree how much power you'll need to reach linear excursion limits.

Hoffmans iron law tells us that there are three interrelated metrics that determine how a subwoofer will perform. Low frequency response, efficiency and enclosure size all affect subwoofer performance. Pick two and the third will be dictated to you.

--Regards,

 

[AcuDefTechGuy]

Yes.



Hoffmans iron law tells us that there are three interrelated metrics that determine how a subwoofer will perform. Low frequency response, efficiency and enclosure size all affect subwoofer performance. Pick two and the third will be dictated to you.

--Regards,

Did I snoozed and missed that part in Physics class?

 

[Vaughan Odendaa]

Hoffmans iron law is a nice way of telling us that we can't break the laws of physics. It's ironclad. Enclosure size, deep bass extension and efficiency are all intertwined. We can, however, bend the laws of physics but that is about all we can do.

For now at least. Now if we could make a Sunfire size enclosure without using extreme amounts of power (making it extremely efficient) and still get deep bass extension to below 20 hz at high output levels, then, maybe, could it be said that we have broken the iron law.

--Regards,

 

[jonnythan]

In other words, you think it's possible for a 300 watts RMS powered sub to produce more bass impact than a 800 watts RMS powered sub in the same exactly room?

Absolutely.

If you want to see how it plays out, go download WinISD and play with various drivers and enclosures.

A 1000 watt amp going to an 8 inch driver in a sealed box can have much lower output and not go nearly as deep as, say, a 300 watt amp driving a 12 inch driver in a large ported box.