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Powersoft X4 real power

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U.Viktor View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote U.Viktor Quote  Post ReplyReply Direct Link To This Post Posted: 12 September 2019 at 9:07am


They have measured bit better values than I.
However "12dB Crest factor" is a very, very low duty.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote snowflake Quote  Post ReplyReply Direct Link To This Post Posted: 12 September 2019 at 11:16am
Originally posted by U.Viktor U.Viktor wrote:



They have measured bit better values than I.
However "12dB Crest factor" is a very, very low duty.


but surely it is harder to output 100W RMS with 12dB crest factor than 100W RMS with 3dB crest factor?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Timebomb Quote  Post ReplyReply Direct Link To This Post Posted: 12 September 2019 at 12:27pm
No, 100W rms with 12dB crest factor is 12.5W real power.

Continual sine wave is 3dB crest factor, 6dB CF is 1/2 the real power (50% Duty cycle),  9dB CF is 1/4 the real power (25% duty cycle) 

Very heavy bass in some music can be as low as 6dB crest factor, most music is higher, 9-12dB typical.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Timebomb Quote  Post ReplyReply Direct Link To This Post Posted: 12 September 2019 at 12:30pm
Its harder to put out 630W continual sine wave than it is to put out 3240W with 12dB crest factor (405W real power),  there is more real power content in the 630W sine wave,  but musical signals always have some crest factor.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote toastyghost Quote  Post ReplyReply Direct Link To This Post Posted: 12 September 2019 at 12:38pm
Originally posted by Timebomb Timebomb wrote:

Its harder to put out 630W continual sine wave than it is to put out 3240W with 12dB crest factor (405W real power),  there is more real power content in the 630W sine wave,  but musical signals always have some crest factor.  


The lowest crest factor I have ever seen on any event or track is 4.8, and it was for a very, very brief period and maybe two out of hundreds of tracks I’ve checked.

Even 6 is rare for any length of time, even on dubstep or drum and bass, if the tune is well mastered.

Of course this all goes to shit if the ‘engineer’ decides to compress the DJ feed or is slamming hard into brick wall limiting or clip all night.

Likewise, there are very, very few drivers that can handle real power of more than 500w for any length of time before thermal compression starts to rob you of output and the downward slide begins. Even a well known, very well regarded, well cooled 21” has a real power limit of 900w maximum for 500 seconds before it starts to hit thermal compression. It’s 500w ‘long term” which is reached after half an hour of drive above that theshold. That time doesn’t necessarily have to be consecutive and of course bursts above those values contribute to the overall decline too, so now think about spanking your rig for an 8 hour Clubnight, or a 12 hour festival stage, or a 24hr 9 day psytrance party...

Also, those values are with all channels driven with the same load and the same output signal, which is broadband. If you load the amp as sub/low/mid/high as intended for a
four channel DSP touring amplifier then the values will vary and more power will be delivered to the appropriate channels.

Care to show me a studio monitor that will do continuous low crest factor output for several seconds without limiting?

Edited by toastyghost - 12 September 2019 at 12:49pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Timebomb Quote  Post ReplyReply Direct Link To This Post Posted: 12 September 2019 at 12:52pm
How are you measuring crest factor live out of interest?  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote toastyghost Quote  Post ReplyReply Direct Link To This Post Posted: 12 September 2019 at 1:00pm
Originally posted by Timebomb Timebomb wrote:

How are you measuring crest factor live out of interest?  


Suitable voltmeter setup on a duplicated output of the console seemed to work well enough to get an idea. It’s an awkward mess but now I just do it analysed non-clipped wav recordings of the same set after the show.

I have quite the library of event recordings of various styles of music, all straight out of the console, all post-processing.

You can also export the data from a Powersoft X series and calculate RMS vs peak voltage at the output stage in Excel.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Speaker Sol Quote  Post ReplyReply Direct Link To This Post Posted: 12 September 2019 at 1:55pm
Originally posted by toastyghost toastyghost wrote:

Originally posted by Timebomb Timebomb wrote:

How are you measuring crest factor live out of interest?  


Suitable voltmeter setup on a duplicated output of the console seemed to work well enough to get an idea. It’s an awkward mess but now I just do it analysed non-clipped wav recordings of the same set after the show.

I have quite the library of event recordings of various styles of music, all straight out of the console, all post-processing.

You can also export the data from a Powersoft X series and calculate RMS vs peak voltage at the output stage in Excel.

Clap

Im finding it hard to find time for this sort of study since I've gotten so busy. However its inspiring to hear its possible! 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 12 September 2019 at 2:30pm
"Likewise, there are very, very few drivers that can handle real power of more than 500w for any length of time before thermal compression starts to rob you of output and the downward slide begins. Even a well known, very well regarded, well cooled 21” has a real power limit of 900w maximum for 500 seconds before it starts to hit thermal compression. It’s 500w ‘long term” which is reached after half an hour of drive above that theshold. That time doesn’t necessarily have to be consecutive and of course bursts above those values contribute to the overall decline too, so now think about spanking your rig for an 8 hour Clubnight, or a 12 hour festival stage, or a 24hr 9 day psytrance party..."

Yes, which is why it´s always far better to add more (efficient) cabs/drivers than 'swop out' an existing driver for something 'with more power' - a request I get constantly from those who don´t have a clue - and have bought (cheapo)  cabs with stupidly inflated power ratings. The first question those ask is always "what power" rather than "what spl".    Unhappy


Earplugs Are For Wimps!
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Post Options Post Options   Thanks (0) Thanks(0)   Quote toastyghost Quote  Post ReplyReply Direct Link To This Post Posted: 12 September 2019 at 4:35pm
Don’t go thinking the modern drivers are mythically rated. They aren’t. There is no escaping that you need high current handling and a modern driver structure to be able to achieve the SPL that is required into the lower notes with modern music. The same tests on older drivers show even lower real power values, and yes, RMS Watts was always a bullshit spec.

No matter the box design or size, there are inefficiencies at the lower, true sub bass region and those only get more pronounced with high signal levels.

The problem is, so many people only measure - if at all - with small signals and take that as gospel.

But this is a double edged sword and to do both requires a more complex and scientific approach to defining the DSP, amplification platform and limiting to ensure the box performs properly without getting cooked or shredded. A really, really common problem I see is high pass filters that do not allow sufficient excursion to cool the magnet assembly, as well as not taking advantage of box tuning efficiencies to ensure a desired reasonably linear - or not - response when driven at gig levels.

Sorry for all the edits, I’m on travels with crap signal and phone posting so it times out whilst writing sometimes!

Edited by toastyghost - 12 September 2019 at 4:37pm
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Elliot Thompson Quote  Post ReplyReply Direct Link To This Post Posted: 12 September 2019 at 5:36pm
Originally posted by Earplug Earplug wrote:



Yes, which is why it´s always far better to add more (efficient) cabs/drivers than 'swop out' an existing driver for something 'with more power' - a request I get constantly from those who don´t have a clue - and have bought (cheapo)  cabs with stupidly inflated power ratings. The first question those ask is always "what power" rather than "what spl".    Unhappy




What you are saying is falling upon deaf ears. The majority wants to extract every bit of SPL from the least amount of loudspeakers and, are not content until the amplifier clips during the process.

 

Best Regards,

Elliot Thompson
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Post Options Post Options   Thanks (0) Thanks(0)   Quote csg Quote  Post ReplyReply Direct Link To This Post Posted: 12 September 2019 at 7:48pm
all of this is largely academic. Those who appreciate uncompressed, dynamic and high quality reproduction will be very happy with the performance of products such as the X series. Those who need to rinse every last ounce of SPL from not enough speakers will not.
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