davedotco said:
One could buy a pair of these Morels with 3" voice coil and hot rod his Q Acoustics. Try killing those with a soft clipping NAD D 3020.
http://www.parts-express.com/morel-caw-538-5-cast-frame-woofer--297-082
Neptune_Twilight said:
Infact lab test after the mess on the official NAD lab in my area provided there WERE no distortion and NO clipping becouse there is such a prevention method in all the modern NAD amp and especially on this brand new class D.
steve_1979
Well-known member
steve_1979
Well-known member
lindsayt said:
I'm not sure why you need someone to be having a bet with you in order to try out this little experiment. If you want to give it a try just go for it. If you need me to say that I'll have a sporting bet with you then yeah sure why not? I do think that they will survive short, non clipped peaks of 70 watts. Just don't expect me to give you any money if you win.
I do hope you give it a try though as it would be very interesting to hear the results.
Out of interest what equipment will you be using to measure the amplifiers power output? I'm no expert but I think a voltmeter would do the job.
BigH
Well-known member
Of course £150 speakers will use cheap components, even some more expensive speakers use fairly cheap components. The 2020i woofers are prob. less than £5, as said they have to make them for less than £50.
I'll tell you why. Because I'd have to fork out £150 for a pair of speakers that I'd have no intention of keeping, even if they passed my power handling tests. That's a bit too much money for me to spend, just to prove a point on an Internet forum. If it was something like £15 I'd go ahead and do it.steve_1979 said:I'm not sure why you need someone to be having a bet with you in order to try out this little experiment. If you want to give it a try just go for it. If you want me to say that I'll have a sportmans bet with you then yeah sure why not. I do think that they will survive short, non clipped peaks of 75 watts*. Just don't expect me to give you any money if you win.
I do hope you give it a try though as it would be very interesting to hear the results.
Out of interest what equipment will you be using to measure the amplifiers power output? I'm no expert but I think a voltmeter would do the job.
* Using normal music with a normal amount of DR. If you want to use a sine wave for the test or some other unusual wave form then the sportmans bet is off.
I'd be happy to use whatever calibrated measuring equipment someone could provide for checking the power levels. My initial thoughts are that I'd use a voltmeter backed up by a calibrated sound pressure meter and a tape measure (for measuring 1 metre distance from the speakers for the SPL).
Yes, of course I'd be happy to use a selection of music CD's for this test. We don't know what sort of dynamic range was on the recordings that MaxD played through his 2020i's. I don't think that anyone in this thread has suggested that MaxD's speakers failed because his CD's were too compressed? That would be a crass statement to make, as every hi-fi speaker ever made has to cope with compressed recordings, and it's only reasonable to expect the 2020i's to be able to do so too.
steve_1979 said:lindsayt said:
I'm not sure why you need someone to be having a bet with you in order to try out this little experiment. If you want to give it a try just go for it. If you want me to say that I'll have a sportmans bet with you then yeah sure why not. I do think that they will survive short, non clipped peaks of 75 watts*. Just don't expect me to give you any money if you win.
I do hope you give it a try though as it would be very interesting to hear the results.
Out of interest what equipment will you be using to measure the amplifiers power output? I'm no expert but I think a voltmeter would do the job.
* Using normal music with a normal amount of DR. If you want to use a sine wave for the test or some other unusual wave form then the sportmans bet is off.
Let's think about this for a moment.
Let us assume that we have an accurate way of measuring peak power on a music signal, not as easy as you might think, a regular digital voltmeter would propably be two slow and have the wrong characteristics. But assume we have a way to do this and the 2020is are connected to our big power amp.
Lets play some music, some fairly heavy rock or moderm 'pop' material of some kind as mentioned earlier in the thread. We know that such recordings have a very modest dynamic range so the continuous power related to 75 watt peaks could easily be 15-25watts.
Now apply this power to the speakers long term, over half an hour, an hour or more, and given that music of this nature rarely has much in the way of quiet passages, is often bass heavy, the heating effect on the coil and former could cause deformation, leading to contact of the distorted coil/former on the magnet and subsequent catastrophic failure. So in this respect lindsayt might well win his bet.
However try the experimeny again, this time with material with wider dynamic range, and a much less persistantly loud presentation, anything classical, piano and voice, well recorded jazz etc. In this case the continuous power, even on peaks will be much lower due to the increased dynamic range and there is often quieter passages so that the coil has time to cool. Under these circumstances I would doubt that you would get remotely close to damaging the speaker.
Most peoples listening habits will probably fall between these extremes which I think makes the manufacturers rating of 25-75 watts perfectly reasonable. The lack of any reliability issues with the 2020i on the web pretty much backs this view.
From the Q Acoustics 2020i User Manual:
1) Play Cream by Prince at 60dB at 1m.
2) Turn system off for 60 minutes for voice coils to cool off.
3) Repeat.
1) Play Cream by Prince at 60dB at 1m.
2) Turn system off for 60 minutes for voice coils to cool off.
3) Repeat.
Vladimir said:
In reality a lot of Prince's stuff has a quite reasonable dynamic range. Some soft passages too.
I think in this case it mught be the listener that needs cooling off.......
Well, I wouldn't have anything to do with a new pair of Q Acoustics 2020i, so I wouldn't take the whole bet. But I would join a shared bet just for the fun of it. So I'd take a part of the cost if lindsayt takes another part, and maybe a couple others join. What's again the price of a new pair of Q Acoustics 2020i in the UK?
I am sure we can all trust davedotco to be the referee here and set the terms for what the conditions of a fair test would be.
I'm just not sure what we should do with the speakers if we don't get to break them… And if we do, we can always do as MaxD, complain to the seller, and get a new pair.
I am sure we can all trust davedotco to be the referee here and set the terms for what the conditions of a fair test would be.
I'm just not sure what we should do with the speakers if we don't get to break them… And if we do, we can always do as MaxD, complain to the seller, and get a new pair.
steve_1979
Well-known member
lindsayt said:
I too have no need for a pair of 2020i's nor £200 to give away if I lost the bet.
It would be an interesting experiment to try though. It would be interesting to start off with easy music and gradually build up to the lower dynamic ragnged music before trying it out with sinewaves to see at what point they died.
steve_1979
Well-known member
davedotco said:
What could be used to measure the power output during the very short instantaneous dynamic peaks that are found in music?
Are there no voltmeters that would be fast enough?
Vladimir said:
:rofl:
That actually makes sense, so that we know that the sample speakers are level with the previous ones and thus, the test is valid. Very important.
After how many pairs of broken speakers will the dealer tell us to EDITED off?
steve_1979 said:
I would think that the only way to really capture the very fast transient peaks would be an osiloscope, even then the response of the 'scope would have to be very carefully set up with regard to response time and the like.
Moving coil meters of all types are far too slow, led arrays are fast enough but the electronics used to drive them are set up to produce results averaged over a few fractions of a second, probably missing very fast transients.
Anyway, it doesnt really matter, the drive units in budget hi-fi speakers are built to the standards required to do the job, no more, no less. You probably could arrange situations that would see the speakers fail when perhaps they should not, but since they are virtually never going to be used in such a way, this really is not going to happen.
Feel free to search the web, there are plenty of expert reviews and dozens of user comments, I could not find one complaining about the fragility of the 2020i.
If the speakers fail within their recommnended parameters then they should be covered by warranty but given that q acoustics offer a 5 year warranty on all their speakers they're not likely to fail under normal use anytime soon and I'm guessing there would be more complaints if that wasn't the case.
davedotco said:
Why do you want to generalize? Speakers are all different. Example: MA BX2 are a lotal different from cheap Q Acoustics 2020i. The point is not to arrange situations where they fail or they doesn't, the point is any speaker in this world shouldn't NEVER FAIL when they are used within specification.
And this is NOT the case of Q Acoustcs 2020i, becouse they failed in my experience within specifications, and other hardware (amp, other speakers, various component) didn't.
And they were totally used within specification, remember this. So a good brand should be very, very carefull IN ANY situation it will NOT fail within specification.
And also, you generalize about hardware, then thick cartoon 2020i woofers are a lot different from solid MA BX2 woofers even if price specs is not that different.
So, even your siperficial and opinionated posts, have little common sense and this is also the reason becouse seller exhange me failing, cheap 2020i under warrantly, and Q Acoustics sent him replacements under warrantly: becouse they had to accept the fact those speakers were completely used under specification, and they probably knows how they woofer are made.
Now, please, don't tell every speaker is the same, becouse in my experience and in my environment the only component to fail were Q Acoustics 2020i.
For me the case is closed: I'm happy with my new speakers, I didn't had to remit money, and now I have decent bookshelf speakers for my need and I learned to always trust my ears - like I always did - and not genorous 5 stars by magazines.
I learned something really interesting in this forum and for those posts I say thank you to the people active in this thread, surely those posts wasn't yours.
MaxD said:
I 'generalised' in my description of the way these things work for two reasons.
The first being that I thought an overall view on the way these things work would be interesting to some of the people reading this thread.
Secondly I thought by not being specific or confrontational we could discuss this matter sensibly. It appears that I was wrong.
It also explains why the dealer gave you free replacements, in his position I would probably have done the same.
@ davedotco
What would you do if someone bought a set of speakers from you and now the speakers don't work anymore because the owner didn't treat the speaker like they should be treated (read ; drove them far too loud).
Of course you don't know what the owner did (because most people won't be telling you what they did..........they just want replacement speakers).
How do you handle these kind of situations ?
Did this ever happen when you were a dealer ?
What would you do if someone bought a set of speakers from you and now the speakers don't work anymore because the owner didn't treat the speaker like they should be treated (read ; drove them far too loud).
Of course you don't know what the owner did (because most people won't be telling you what they did..........they just want replacement speakers).
How do you handle these kind of situations ?
Did this ever happen when you were a dealer ?
You are right about Q acoustics always getting good ratings in WhatHiFi.
Personally I would listen to them first before listening, as the company does not have the same pedigree and international sales as other companies.
That's not to say they don't produce some good stuff, however the ones you have are budget speakers.
If you want loud, then you obvious route is larger diameter cones. These are small.
Probably great in a small living room where the volume is kept at moderate levels.
And you are right about the amplifier being OK and not clipping as the tweeters would have blown first.
Bottom line is you need better and louder speakers.
Personally I would listen to them first before listening, as the company does not have the same pedigree and international sales as other companies.
That's not to say they don't produce some good stuff, however the ones you have are budget speakers.
If you want loud, then you obvious route is larger diameter cones. These are small.
Probably great in a small living room where the volume is kept at moderate levels.
And you are right about the amplifier being OK and not clipping as the tweeters would have blown first.
Bottom line is you need better and louder speakers.
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