Hi All,
I am fairly new here but have lurked over the years. I co-chair the CTA standard committee working group that has oversight on this power amplifier standard. We are currently working on some revisions to it that will ultimately become CTA-2006C.
I am curious how many people look for this power rating on amplifiers and find it helpful. Any feedback is appreciated.
I am fairly new here but have lurked over the years. I co-chair the CTA standard committee working group that has oversight on this power amplifier standard. We are currently working on some revisions to it that will ultimately become CTA-2006C.
I am curious how many people look for this power rating on amplifiers and find it helpful. Any feedback is appreciated.
my tenure with car audio is less than ten years but in that relatively short time i've come to the conclusion that a standard is less important than large numbers....seems the only thing that matters is watts! long term thermal stability and distortion percentages are apparently irrelevant.
too many manufacturers fudge their specs with instantaneous peak power ratings in order to entice consumers with incredible power output ratings.
just my
too many manufacturers fudge their specs with instantaneous peak power ratings in order to entice consumers with incredible power output ratings.
just my
I don't. And I don't understand the first paragraph at all. Power rating? do you mean Watts RMS? They are what they are........
Yes, that is what I am referring to. As Turk 182 points out, the numbers published on the box are often W.L.S. ratings (When Lightning Strikes).
Well, stick with rms, it is a standard, I don't see the point of anything else other than to cloud the issue for obvious reasons
even RMS ratings can be fudged depending on what the input signal consists of, as in short duration pulse, sine, pink noise, the AES itself is unclear as to current accepted "standards" because of "members" that are also involved in manufacturing have called into question the standards for their own vested interests.
so unless full disclosure of details of tests are made it's still a crap shoot hence the need for the study, shame that their is no legal requirement for manufacturers to comply.
so unless full disclosure of details of tests are made it's still a crap shoot hence the need for the study, shame that their is no legal requirement for manufacturers to comply.
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the last time i saw a car amp that gave an RMS rating into a specified load impedance along with a bandwidth was the mid 70's....
1, 2 and 4 ohm purely resistive loads (no reactance). Lower ohm loads for amps rated to drive lower ohm loads
50 and 100Hz sine wave for subwoofer amps. Add 1kHz for full range amps.
lowest maximum power (less than 1% THD+N) during a 30 second run (to determine constant power output, not power from energy stored in rail caps)
Fixed voltage (13.8 preferred because it's more attainable than 14.4 in a vehicle)
50 and 100Hz sine wave for subwoofer amps. Add 1kHz for full range amps.
lowest maximum power (less than 1% THD+N) during a 30 second run (to determine constant power output, not power from energy stored in rail caps)
Fixed voltage (13.8 preferred because it's more attainable than 14.4 in a vehicle)
Haha, why did I know you were going to say that?
What's used to take the measurement, sine wave, pink noise, white noise.....
What's used to take the measurement, sine wave, pink noise, white noise.....
sawdust123 i'm glad Mr Babin has weighed in, his knowledge and experience in car audio far outstrips any contribution i could make.
sorry i don't know what your trying to say as your being non specific and vague.
without the details, any test results can be fudged.
still don't understand the relevance of referring to another thread?
If you look up "16 CFR 432" you will find how the US Govt defines RMS power. This is in the Code of Federal Regulations and it ONLY applies to 2-channel home stereos. It does not apply to car amps, multi-channel amps, pro-audio, powered speakers, etc.
I like this definition for several reasons:
1) It has a preconditioning requirement
2) It has a relatively long duration
3) The DUT must be below the rated distortion from 1/4 watt to the rated power
Manufacturers hate the spec for the same reasons I like it. It is hard to fudge the numbers.
Anyhow, I have been selling audio analyzers for more than a decade. They all measure rms voltage and can do so with a very short duration signal. A short duration rms measurement is not the same as 16 CFR 432 even though the actual voltage reading is done the same way. In other words, not all rms values are equal.
I gave a talk at Rocky Mountain Audio Fest in 2015 on this topic. You can find a video of it by searching for "RMAF15: What the Specs Don't Tell You and Why." If you look carefully, you will find some regulars from these forums in attendance.
I like this definition for several reasons:
1) It has a preconditioning requirement
2) It has a relatively long duration
3) The DUT must be below the rated distortion from 1/4 watt to the rated power
Manufacturers hate the spec for the same reasons I like it. It is hard to fudge the numbers.
Anyhow, I have been selling audio analyzers for more than a decade. They all measure rms voltage and can do so with a very short duration signal. A short duration rms measurement is not the same as 16 CFR 432 even though the actual voltage reading is done the same way. In other words, not all rms values are equal.
I gave a talk at Rocky Mountain Audio Fest in 2015 on this topic. You can find a video of it by searching for "RMAF15: What the Specs Don't Tell You and Why." If you look carefully, you will find some regulars from these forums in attendance.
I was told by an amp manufacturer that anybody can achieve this certification with paying a fee and no testing is actually done.
Seankane, what certification are you talking about? Normally, certification is only applied for licensed logo programs like DTS, Dolby, HDMI, THX, et cetera. The CTA is not such a licensing agency.
The CTA standard can be used by anyone that purchases a copy of the standard. The manufacturer is responsible for doing their own testing and there is no formal policing. I honestly can't say what the penalty for abuse of the logo is but I can imagine it impacts CTA membership or one's booth at CES. The CTA is not a governmental agency. However, I suppose they could sue for trademark infringement.
The CTA is not a testing agency. The only way they would know if the logo was being misused is if someone complained and had data to back up those claims.
Based on some of the non-CTA power ratings I see on amplifier boxes, I can be pretty sure no test equipment was touched during the authorship of those numbers.
The CTA standard can be used by anyone that purchases a copy of the standard. The manufacturer is responsible for doing their own testing and there is no formal policing. I honestly can't say what the penalty for abuse of the logo is but I can imagine it impacts CTA membership or one's booth at CES. The CTA is not a governmental agency. However, I suppose they could sue for trademark infringement.
The CTA is not a testing agency. The only way they would know if the logo was being misused is if someone complained and had data to back up those claims.
Based on some of the non-CTA power ratings I see on amplifier boxes, I can be pretty sure no test equipment was touched during the authorship of those numbers.
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