DataBase of Brent Butterworth's sub measurements

[KEW]

I just found this!
It is not so comprehensive as most, but provides CEA measurements for several subs I have not seen measured elsewhere (such as Rythmik F12)


https://docs.google.com/spreadsheets/d/1KjlXBWMPAHgU_V9DAHSdIZ_ke0MxwH6ekt3vTIlYOJU/edit#gid=0

 

[KEW]

I just wanted to ping this.
Brent has been busy!
This table is populated with a lot more subs than it was last time I looked (now at 77 subs* and seems like it was about 20-25 when I made the above post 8.5 months ago)!

CTA-2010 results

docs.google.com

*technically less than 77 because he tests some of the adjustable subs in both sealed and ported mode!

Here is an interesting compilation of this data for a select few of these subs:

 

[rrj]

@KEW ,

Do you know if these measurements are peak, or RMS?

Thanks in advance!

 

[lovinthehd]

@KEW ,

Do you know if these measurements are peak, or RMS?

Thanks in advance!

Not Kurt, but maybe this will help out https://www.x3mhc.no/dokumenter/starobin_CEA2010.pdf or maybe this https://www.audioholics.com/loudspeaker-design/2010-subwoofer-shootout/2010-subwoofer-shootout

 

[KEW]

@KEW ,

Do you know if these measurements are peak, or RMS?

Thanks in advance!

As Loving says, they are CEA2010 measurements, either limited by distortion limits or peak level if distortion is not excessive.

 

[shadyJ]

@KEW ,

Do you know if these measurements are peak, or RMS?

Thanks in advance!

The measurements in Brent's spreadsheet are scaled to 1 meter peak. If you want to compare those measurements to data-bass's or Audioholics', you have to subtract 9 dB from Brent's measurements.

 

[lovinthehd]

The measurements in Brent's spreadsheet are scaled to 1 meter peak. If you want to compare those measurements to data-bass's or Audioholics', you have to subtract 9 dB from Brent's measurements.

Can you expand on that please?

 

[KEW]

Can you expand on that please?

Butterworth specifies on his chart that the measurements are:

CEA-2010 results scaled to 1M equivalent (updated 4/20)

I know 1m is also the way Hsu specifies their data. I'm not sure why which is used where, but I suspect most subwoofer vendors will use the 1m value which allows them to publish bigger numbers!
It is a shame that a consistent value used by all is not the rule!

 

[lovinthehd]

Butterworth specifies on his chart that the measurements are:

I know 1m is also the way Hsu specifies their data. I'm not sure why which is used where, but I suspect most subwoofer vendors will use the 1m value which allows them to publish bigger numbers!
It is a shame that a consistent value used by all is not the rule!

I was more wondering why it's 9dB instead of 6dB for doubling the distance to 2m. I may be a bit thick today, allergies have had me using up all my paper supplies!

 

[KEW]

I was more wondering why it's 9dB instead of 6dB for doubling the distance to 2m. I may be a bit thick today, allergies have had me using up all my paper supplies!

Ahh!
I was kind of wondering if I was actually telling you something that you didn't already know!

 

[lovinthehd]

LOL I could say it was just for @rrj but even though I've seen an explanation I'm pretty sure, I can't think of it.

 

[shadyJ]

I was more wondering why it's 9dB instead of 6dB for doubling the distance to 2m. I may be a bit thick today, allergies have had me using up all my paper supplies!

The CEA-2010 protocol states that numbers should be scaled to 1 meter peak values, even though testing is done at 2 meters. Butterworth and Hsu are adhering to the protocol.

If you double the distance, measured output is reduced by 6 dB. If you go from peak values to RMS values, the values are reduced by another 3 dB. Some people feel that 2 meter RMS values are more reflective of what would be felt in actual listening situations.

 

[lovinthehd]

The CEA-2010 protocol states that numbers should be scaled to 1 meter peak values, even though testing is done at 2 meters. Butterworth and Hsu are adhering to the protocol.

If you double the distance, measured output is reduced by 6 dB. If you go from peak values to RMS values, the values are reduced by another 3 dB. Some people feel that 2 meter RMS values are more reflective of what would be felt in actual listening situations.

Thanks. So the 3 dB difference is simply a calculation between continuous and peak? Or part of the measurement routine?

 

[shadyJ]

Thanks. So the 3 dB difference is simply a calculation between continuous and peak? Or part of the measurement routine?

Just a calculation.

 

[rrj]

The measurements in Brent's spreadsheet are scaled to 1 meter peak. If you want to compare those measurements to data-bass's or Audioholics', you have to subtract 9 dB from Brent's measurements.

@shadyJ ,

That was why I was asking, to compare data from other sources. Thanks for responding.