rms vs aes
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Category: General
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URL: https://forum.speakerplans.com/forum_posts.asp?TID=42144
Printed Date: 16 April 2024 at 7:47pm
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Topic: rms vs aes
Posted By: myser
Subject: rms vs aes
Date Posted: 14 August 2010 at 6:07am
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is the rms rating higher than the aes rating .. how does this work . so if a driver is rated at 800 aes what would i expect the rms to be .. ? confused ..
------------- myser |
Replies:
Posted By: subbass
Date Posted: 14 August 2010 at 12:04pm
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http://lmgtfy.com/?q=aes+power+rating - http://lmgtfy.com/?q=aes+power+rating
AES is same as RMS, but 3rd party verified AES = RMS, but AES can be relied on 100% unlike RMS
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Posted By: _djk_
Date Posted: 14 August 2010 at 12:31pm
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You really need a time to be specified on RMS. Once the whole magnet and frame reach their maximum temperature the power rating goes way down. AES is a very short duration test (under 2 hours IIRC). A 100 hour RMS rating (like the old JBL ones) will be much lower. ------------- djk |
Posted By: myser
Date Posted: 15 August 2010 at 7:16am
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mmm .. conflicting answers
------------- myser |
Posted By: cnc123
Date Posted: 15 August 2010 at 6:32pm
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In short As a general estimate or a gest-ermate the “rms” is a third less of the “aes” quote myser “so if a driver is rated at 800 aes what would i expect the rms to be” = 600w rms approx before the 80s speak power ratings where for use with valve amps generally of small power so you had British and American watts rms with no standard test procedure British ratings where “Continuous rms” (sinewave at min impedance typically 400Hz) or “Nominal rms” (normal watts, What normal?. dictionary explanation. existing in name only) Like old Goodman speak for example Amercan ratings at 1kHz rms and later on a aes test for 8 hours all gave higher numbers Djk the man to ask especially on the history of American ratings and all the other rating example IEA DIN IEEE IEC FTC ANSI and more. dont ask question with answers. thats negative but with why why why untill you get and understand the answers you want P.s workt especially well when I was under 10 |
Posted By: Sibulus
Date Posted: 15 August 2010 at 9:32pm
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http://www.doctorproaudio.com/doctor/temas/powerhandling.htm a good read. OP, are you a Buddist by any chance? ------------- http://soundcloud.com/judas-beast |
Posted By: _djk_
Date Posted: 16 August 2010 at 3:20am
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That last reference at http://www.doctorproaudio.com/doctor/temas/powerhandling.htm - http://www.doctorproaudio.com/doctor/temas/powerhandling.htm Is quite good until the end of part 4 (causes of speaker failure),
and part 5 (selecting amplifier power). In general, the amplifier power needs to be larger than the speaker's rated power. This is because an amplifier only delivers its rated output power with sinewave signal, and delivers much less with a real signal with dynamics. Totally backwards. Every amplifier puts out WAY more than its rated RMS power on program material. The only possible exception to this would be an amplifier with foldback current limiting trying to drive a very reactive loudspeaker into its rated minimum load. Four 8 ohm woofers in parallel are an example of this, unless the amplifier is expressly designed to do so (an example of this would be the QSC RMX 1850HD. An 1850HD is a 2450 with a reduced voltage, increased amperage transformer. In spite of its reduced power output at 2R, 900W vs 1200W, it still only carries an EIA rating at 2R, and not an FTC rating like it does at 8R and 4R). The Crown VZ series are another example of the above, when driving four 8 ohm woofers in parallel the ODEP lights will occasionally flash (even if not clipping). When this occurs the amplifier cuts its power supply voltage in half (in theory reducing power by a factor of four). Yes, a VZ will drive even a 1R load, but it will lock itself down into low voltage mode (to protect itself). It will also lock down to low voltage mode if it gets too hot for a long period of time. An Altec 9440 was an old favorite of mine, it too would lock down to a lower supply voltage if you got it too hot driving a low impedance. It also had a thermal shut-off if things got out of hand (fan failure or similar). will continue later As ageneral guideline, it is recommended to use an amplifier delivering 50% more power than the speaker's average ("RMS") power. For example, for a speaker with 450W average power, an amplifier with an output of 700W may be used. If a small amplifier is used, sufficient level will not be reached, nor the perception that it is attained, so the signal will tend to be clipped to compensate, thus endangering the integrity of the speaker. The cabinet design also affects thermal power ratings too. It's all about getting rid of the heat, a tightly sealed rear chamber can't get rid of the heat (without some external heat exchanger). ------------- djk |
Posted By: cnc123
Date Posted: 16 August 2010 at 3:34am
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arr grasshopper not gras-shoppper you guess http://www.youtube.com/watch?v=WCyJRXvPNRo&feature=related - http://www.youtube.com/watch?v=WCyJRXvPNRo&feature=related |
Posted By: cnc123
Date Posted: 16 August 2010 at 5:44am
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arrr djk enlighten us some more to be continued later you said I shall have patience till then the fat Buddha p.s nice one about the amps |
Posted By: bass traffic
Date Posted: 16 August 2010 at 6:03am
| Good reading this thread, hopefully I'll remember to keep checking it! |
Posted By: myser
Date Posted: 17 August 2010 at 6:31am
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cheers for info guys... yep am Buddhist ... Chinese proverb say - " he who goes to bed with itchy bum awaken with smelly finger " ------------- myser |
Posted By: myser
Date Posted: 17 August 2010 at 5:59pm
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what about "nominal power handling " as a power rating ... ?
------------- myser |
Posted By: cnc123
Date Posted: 18 August 2010 at 3:49am
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nominal is just another word for normal what ever normal is? is just a matter of opinion a dictionary definition for example is "existing in name only" the problem is you (not you personally) and generally other Joe's want to buy the biggest power ratings possible in terms of electrical consumption (like a car less mpg and no more mph) what you should be asking for is the largest acoustical output measured in acoustical watts or dBLw (the sound power) typically a 18" 1000w speak outputs 10 acoustical watts which dosnt sound very big to the sales department or the Joe's |
Posted By: markjameslong
Date Posted: 18 August 2010 at 10:52pm
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ok so if i have 2 bass bins at 1600 aes 4R, what rms power amp should i be looking at? also what is a good way to run them, both linked down to 2R on one amp bridged or an amp that can power 1600 4R a side, or two amps that will bridge down to 4R? thanks, mark |
Posted By: Mark James
Date Posted: 18 August 2010 at 11:47pm
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never bridge into 2 ohm!!! you make each channel effictively see 1 ohm, realy not good what cabs have you got?
one amp that can push one cab per side at 4 ohm sterio is what I would personaly prefer less stress etc. ------------- me so horny me love you long throw horn loaded for her pleasure |
Posted By: cravings
Date Posted: 19 August 2010 at 12:12am
| yeah if you've got bins at 1600w / 4r... you'll need a good hefty amp for them. one of the 2k+ per side ones... |
Posted By: cnc123
Date Posted: 19 August 2010 at 4:15am
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you need to be more specific example what speak model number, type of box, are you going though a limiter, x-over setting, etc. and hope that djk comes back on here, |
Posted By: FatStuart
Date Posted: 24 August 2010 at 3:57am
| Your speakers should come with a recommended amplifier rating from the manufacturer. As djk said, a lot depends on the cabinet too (which is often forgotten or ignored, foolishly). If you don't know the recommended amplifier rating someone on here will :) |
Posted By: FatStuart
Date Posted: 24 August 2010 at 4:14am
| And I have a question for djk: you say that clipping in itself isn't harmful, but doesn't clipping an amp produce high frequency harmonics which can fry a tweeter in a system using passive crossovers? |
Posted By: _djk_
Date Posted: 24 August 2010 at 11:12am
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No, the extra power content from harmonics when clipping is trivial. With program material with high dynamics, the increase in average power during non-clipped passages is what burns out the tweeters. In general, woofers die from mechanical problems before they die from too much long term average power. It is essential to evaluate the box design and cone excursion on a given design before deciding how much power to hit the cabinet with. ------------- djk |
Posted By: _djk_
Date Posted: 24 August 2010 at 11:37am
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. ------------- djk |
Posted By: tv00
Date Posted: 01 December 2013 at 4:36pm
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I've always been told that clipping will result in a square like
waveform because the wavetops are cutoff, like turbosound & more
show in their guides. Taking a look at cone movement from squarewave looks horrible! The amp will try to force the cone to move from one limit to the other in no time, ripping it hard, then it will keep it in this posistion during the clip wave leaving heat like dc in the coil before pulling it back hard & over again. Is this wrong? The reason I dig into this thread is actually that the digam7000 has 1910w@4ohm / ch measured EIAJ, what is an eaij test? Something about tests here: http://www.doctorproaudio.com/doctor/temas/powerhandling.htm You might be wondering what I'm up to, having 24 pcs fane 18-1500 bph takes some power to drive! I have 4 pcs digam7000, but it's not really enough, So I'm buying two lab gruppen fp13000, This can drive 8 pcs 18-1500 @ 13000w, some people suggested that I use one amp for all 12 subs per side, but this is 6 per channel! I wouldn't do that, normally I never do 2 ohms, only did that with digam & lab. It's a matter of power, I was planning to run each side with one digam with 4 subs & one lab with 8 subs, this is 1910w for the four & 6500 for the eight, not exactly equal, I was thinking to give the 4 bph on top of the stacks less power, as they are likely to have more excursion not coupling ground or boxes on top. Does this make sense? 4 pcs lab 13000 would be better, but they're damn costly! |
Posted By: nativelayer
Date Posted: 05 December 2013 at 1:33pm
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Diving into the nominal power discussion: B + C driver is advertised on one site 200W Nominal Power and another 400W Continous Power. My amp plan had been to power two of these with 400W (x2 Nominal power rating) each side - should I be thinking more along the lines of 800W (x 2 Continous power rating? How much juice would be reasonably safe (theoretically leaving aside box dynamics)? I have looked around regarding this and got confused with all the conflicting answers....Newbie after all :) ------------- There is no authority but yourself. |
Posted By: TENSiON
Date Posted: 05 December 2013 at 2:01pm
2x "nominal" (or 1x program power) is a good value to aim for when it comes to matching drivers to amps. And there is no such thing as "reasonably safe". Never rely on "amp max power" for driver protection - NEVER! That's what your LMS/limiters are for.. |
nativelayer wrote:Posted By: _djk_
Date Posted: 06 December 2013 at 2:20am
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"Is this wrong?"
Completely. ------------- djk |
Posted By: tv00
Date Posted: 06 December 2013 at 6:25am
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Ok? Why? "completely" Is not a very convincing argument:-) actually it's very bad!-( If you say that I'm completely wrong, and not just partly wrong, then I'm sure you're WRONG! The internet is filled with arguments that I present the very logic result of clipping: Wikipedia: "This extra power can cause damage to loudspeaker components" Others: " this is clipping. During this time, the current from the amplifier is heating up the speakers voice coil. Since no additional cone movement is occurring, you essentially have a small stove element. Yep, the one where you make your macaroni and cheese. This voice coil continues to heat up until the glues and varnishes that hold the wires in place fail, or the connection to the cone or spider overheat and fail. And there you have it, a blown speaker." From Peter Papp: "The clipping seriously increase the THD, typically by several tens of %... sounds pretty bad. The clipping strongly increases the AVERAGE Power level and heat dissipation across the voice coil The clipping could create extra harmonics which located may outside (lower / higher or booth) of the actual speaker and this way may hurt the mechanical structures. At the moment of clipping the amplifier completely looses control of speaker movements!" |
Posted By: johannes
Date Posted: 13 March 2014 at 11:05pm
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Couldn't you just put a LowPass filter after the Clipper/peak limiter to smooth out the corners and a Highpass to make the clipped peak not a DC signal? Also, if you're putting an RMS limiter, I would've thought a infinity/1 limiter with a time constant (attack and decay) of maybe 1 second a little below the AES constant power of the speaker would be enough protection. do you guys think it would have to be faster or maybe just at like half the AES wattage and slower? |
Posted By: bitSmasher
Date Posted: 13 March 2014 at 11:18pm
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Posted By: Conanski
Date Posted: 14 March 2014 at 12:10am
All of this applies but the bold part is what damages or destroys speakers most times. Yes that's right.. overpowering is what blows speakers. There are lots of ways to achieve it but that's the crux of it.. too much power for too long. |
Posted By: _djk_
Date Posted: 14 March 2014 at 12:28am
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"clipping strongly increases the AVERAGE Power level and heat dissipation across the voice coil"
This needs to be ammended to clipping strongly increases the AVERAGE Power level and heat dissipation across the voice coil during the non-clipped portion of the music.
This can be as much as 10dB vs the power increase from a sine to a full square wave is only 3dB.
100 hour sine wave data is required, and data on the cooling inside the cabinet as well, if you want to really figure out how much design can actually handle.
Half of the AES rating may be a good place to start. ------------- djk |
Posted By: johannes
Date Posted: 14 March 2014 at 10:10am
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"clipping strongly increases the AVERAGE Power level and heat dissipation across the voice coil during the non-clipped portion of the music." So in a speaker protection circuit, it would be wise to put the peak limiter before the rms limiter? at least if you have a true rms-voltage sensor. "100 hour sine wave data is required, and data on the cooling inside the cabinet as well, if you want to really figure out how much design can actually handle. Half of the AES rating may be a good place to start." 100h sine test data would of course be good data to have from the manufacturer, but what format does the cooling data you speak of have? is it W/°C ? and how would you go about calculating with that number? thank you for your comment, and please don't hesitate to post links with further reading for me if you have them.
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