B&C 21SW152 and 21DS115 long term power handling |
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gen0me
Young Croc Joined: 20 February 2016 Location: UK Status: Offline Points: 999 |
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Strange that you dont heat them long term. You could measure impedance before and during/just after the test and outside temperature.
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Ricci
Registered User Joined: 13 March 2017 Location: Louisville, KY Status: Offline Points: 69 |
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It is very demanding. The reason it is done like this is an effort to produce an accelerated heat buildup. I don't have time or the area for a whole other setup for much longer thermal compression testing over many hours with pink noise. This type of thing is already done with AES testing anyway. Also it will change drastically depending on the enclosure used and signal applied. This type is more abusive over the short term but not as abusive as applying a sine wave at a worst case frequency. At tuning for a vented cab for instance. Most drivers seem to bounce back from being driven to 3-4dB of thermal compression once or twice. I'm not sure that would be the case if heated that much many times. Of course I've burnt up some drivers and also broken some mechanically with this type of test. Using that type of signal also pushes the speaker extremely hard at all of its weak points in the sub bandwidth so it reveals a lot of warts, distortion and other bad distortions or sonic issues. Often driver excursion becomes a limiting factor right at about the time the driver is running into serious thermal issues. Whichever one throws up a flag becomes the limit for that test type. |
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logsquared1
Registered User Joined: 09 February 2017 Location: USA Status: Offline Points: 115 |
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Don't be scared Pedal to the metal Seriously though, If your not putting at least 4Kw peak RMS to a 21SW152 you might as well get a cheaper woofer. |
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Crashpc
Registered User Joined: 26 February 2008 Location: Czech Republic Status: Offline Points: 463 |
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Well, if I rather listen to "square wave music", 2500 seems to be okay. :-D
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Nikon and Canon people should not be married to each other. Why did you let this happen?
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Sirius Sounds
Registered User Joined: 19 March 2017 Status: Offline Points: 54 |
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What's 4kW peak rms? Is it peak or rms?! I was planning on putting about 2k7 rms and i think thats about 4k peak for my amp.
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logsquared1
Registered User Joined: 09 February 2017 Location: USA Status: Offline Points: 115 |
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The available wattage calculated from the maximum RMS voltage capability of the amplifier. Roughly .707 X the Rail voltage. Or the "continuous program" rating used by most woofer manufacturers.
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ReubGold
Registered User Joined: 09 April 2012 Location: Essex/JA Status: Offline Points: 271 |
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If you have sufficient mains supply, would think 2x 4 ohm drivers per channel of 9001, each cab with it's own pair of 4mm2 conductors, should do the job, for reasonably sensitive drivers. |
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If he turns me into a zombie, first person I'm coming after is you.
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Crashpc
Registered User Joined: 26 February 2008 Location: Czech Republic Status: Offline Points: 463 |
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Hey. Digging old corpses I guess... In B&C, they say they put more wire into the magnetic gap with 21DS115, for motor strength. I still cannot wrap my head around how they did it. The math doesn´t work here (Resistance, wire diameter and length) for me. Looks like it is not possible with Aluminium. Yet they did it somehow. That is not the topic though. The more I think about it, the more it seems to me that the Al coil must be beefy one. Significantly greater wire diameter and volume than with Copper. And thicker coil body too, obviously. That might mean good things for cooling capabilities, couldn´t it? Greater coil area and volume/heat capacity. And the weight is also there. Mms of 21DS115 is greater than with 21SW115. The 21SW152 doesn´t have much more coil area than 21DS115, and that is not counting for split coil of 21SW152. It might be, that the coil area of 21DS115 is the same as 21SW152, despite significant difference in the coil diameter. That would certainly make Ricci´s tests slightly less "unbelievable". |
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Nikon and Canon people should not be married to each other. Why did you let this happen?
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